HK1208794B - Intraocular gas injector - Google Patents

Description

Intraocular gas syringe

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 61/658,756, filed on June 12, 2012, entitled INTRAOCULAR GAS INJECTOR, and U.S. Provisional Application No. 61/799,840, filed on March 15, 2013, entitled INTRAOCULAR GAS INJECTOR, the entire contents of which are expressly incorporated herein by reference.

Technical Field

The invention disclosed in this application generally relates to devices and methods for injecting gas into the eye of an animal.

Background Art

Surgery may require the injection of gas or other fluids into a target area to treat specific injuries, disorders, and diseases. When treating eye conditions such as macular holes, retinal tears, and detachments, part of the surgical procedure may include the injection of gas or other fluids into the eye.

In some embodiments, retinal detachment occurs when there is a retinal tear, a retinal traction, or fluid accumulation in the subretinal space causing retina to begin to separate from the RPE tissue of support. This may cause retina to become dislocated and become detached. This may occur due to posterior vitreous detachment (PVD), proliferative diabetic retinopathy (PDR), damage, or the revascularization of the fiber or vascular tissue that causes retina to come off from RPE. Under these conditions, if left untreated, partial vision loss may result and potentially even blindness may occur.

The treatment method about uncomplicated retinal detachment may include non-surgical techniques such as gas retinopexy, laser coagulation or cryo-bonding. More complicated retinal detachment needs to utilize surgical operation. Due to the risk of infection (infection can potentially lead to blindness), this operation is performed under aseptic conditions, thereby significantly reducing the possibility of infection. Surgical method includes vitrectomy for removing vitreous humor; Excision and removal of diaphragm (if traction retinal detachment); and laser coagulation or cryo-bonding (if other retinal tears). According to this surgical procedure, intraocular gas packing can be used to keep retinal tissue in contact with RPE, thereby making retina remain attached during the healing process after the surgical procedure.

Because the pressure inside the eye must remain relatively constant during the healing process, the gas of choice is typically one that expands at a constant pressure (an isobaric process). Thus, the intraocular gas tamponade can be a bubble of air mixed with an expandable gas such as sulfur hexafluoride ( _SF6 ), hexafluoroethane ( _C2F6 ), or octafluoropropane. Depending on _the gas used and the concentration, the intraocular gas tamponade dissolves over time. For example, when sulfur hexafluoride is mixed with air to a concentration of approximately 20%, sulfur hexafluoride dissolves within 1-2 weeks, when hexafluoroethane is mixed with air to a concentration of approximately 16%, hexafluoroethane dissolves within approximately 4-5 weeks, and when octafluoropropane is mixed with air to a concentration of approximately 12%, octafluoropropane dissolves within approximately 6-8 weeks. Changing the concentrations of these gases affects the duration of healing.

Current practice involves using gas contained in separate, multi-dose pressurized containers, which are then transferred to a syringe for mixing with air and injection into the patient's eye. Therefore, during surgical procedures, multiple non-sterile and sterile steps are required to fill the syringe with the desired concentrations of gas and air. These non-sterile and sterile steps are typically performed by a non-sterile operating room circulating nurse and a technician who assists the surgeon with sterile scrubs in a sterile setting. In the first non-sterile step, the circulating nurse prepares a non-sterile, reusable gas container by setting the pressure regulator connected to the gas container to the appropriate pressure. In the second step, the scrub technician prepares a sterile syringe by connecting a stopcock, a filter, and a pipeline in series to the syringe. In the third step, the pipeline is connected to the gas container. The scrub technician carefully passes the free end of the sterile pipeline to the waiting non-sterile circulating nurse through an invisible sterile barrier. The non-sterile circulating nurse then receives the pipeline and carefully ensures that he/she does not contaminate the scrub technician or any other sterile surfaces; and connects the pipeline to the regulator on the gas container. Then, in the fourth step, the syringe is filled with gas from the container. The scrub technician and circulating nurse adjust the opening of the pressurized container valve to release gas into the syringe through the connected pipes, filters, and stopcocks. The pressure of the released gas is sufficient to push the syringe plunger along the length of the syringe barrel and thereby fill the syringe with gas. The scrub technician ensures that the gas does not push the plunger out of the open end of the syringe barrel and signals the circulating nurse to close the gas container valve when the syringe is nearly completely full. Then, in the fifth step, the syringe is purged of all air and gas to ensure that most of the air present in the syringe, stopcock, filter, and pipes is removed before filling with gas. The scrub technician turns the stopcock to provide a method for releasing air and gas in the syringe to the atmosphere; presses the syringe plunger; and empties all the contents of the syringe. The scrub technician then turns the stopcock in the opposite direction, returning the connection path to the pipes and gas container. Repeat steps four and five several times to further reduce the amount of air initially located in the syringe, stopcock, filter, and pipeline; discharge most of the air in the syringe, stopcock, filter, and pipeline and purge the air system. Then in the sixth step, refill the syringe with the gas in the container. The scrub technician separates the pipeline from the filter and sends a signal to the circulating nurse to carefully pick up the pipeline and take it away from the sterile area. In the seventh step, the scrub technician does not discharge the entire contents in the syringe, but stops the plunger so that only the measured gas volume remains in the syringe. For example, the gas can be discharged so that only 12mL of gas remains in the syringe. In the eighth step, the scrub technician replaces the used filter with a new sterile filter and inhales filtered room air into the syringe until the entire air/gas mixture in the syringe is at a suitable volume for the desired gas concentration.

For example, atmospheric air can be drawn into the syringe so that the total volume of air and gas is 60 mL, thereby achieving a 20% concentration. Because the pressurized container is non-sterile and the syringe and surgical field are sterile, the above-described steps must be performed by at least one person in the non-sterile area (usually a circulating nurse) and a second person in the sterile area (usually a scrub technician), requiring collaboration and communication between the two parties.

The procedure requires a complex set of steps that increase the likelihood of error. An error in one of these steps could result in an inappropriate concentration of the gas used, resulting in elevated pressure or a reduced duration of retinal tamponade, which could lead to ischemia or failure of the detachment repositioning procedure, both of which could result in blindness. Furthermore, current practice results in the waste of large amounts of gas, which increases costs and harms the environment. Therefore, improper handling of these gases, particularly in pressurized containers containing more than one dose, can pose a potential hazard to the operator. Consequently, some countries even prohibit the storage of these pressurized containers within operating rooms.

While some solutions have been used to improve current procedures, such as the single-dose container that can be placed in a sterile area and the system that allows for filling and purging of gas as described in U.S. Patent No. 6,866,142 to Lamborne et al., these solutions are insufficient to address all potential problems. Therefore, there remains a need in the industry for improved gas mixing devices.

Summary of the Invention

At least one aspect of the invention disclosed herein includes an embodiment in which an intraocular gas injector design allows a surgeon or nurse to prepare a gas mixture with a selected concentration level using a simple procedure. For example, in some known intraocular gas injector devices and procedures, such as in a conventional syringe, multiple people may be required to fill the syringe to achieve the desired concentration, with one person repeatedly filling and releasing the syringe and another person controlling the flow of gas contained in an external tank. In addition, each person must coordinate their operations and perform multiple complex steps. This increases the possibility of errors during the filling process, which may result in an inappropriate concentration being achieved in the syringe before injection into the patient. Moreover, the time required to fill the syringe is increased because both parties must coordinate their operations and perform multiple steps. In certain medical fields such as ophthalmology, this potential for error is particularly dangerous, where injecting an inappropriate concentration may result in blindness. Therefore, an intraocular gas injector operated by a single person may help reduce the possibility of errors.

At least another aspect of the invention disclosed herein includes embodiments in which an intraocular gas injector design may allow for a variety of selectable concentration levels, thereby allowing a single device to be used for different applications and thereby potentially further reducing manufacturing costs and reducing waste. For example, some conventional devices only allow for a preset concentration level to be achieved in the device, necessitating the manufacture and storage of multiple devices with different preset concentration levels. This increases manufacturing costs and the costs to surgeons who may need to purchase multiple devices to meet the needs of different surgeries. In such cases, some devices may become obsolete before being used, requiring the manufacturer or surgeon to discard the devices. Therefore, an intraocular gas injector that allows for multiple concentration levels can be provided as a universal device to surgeons, thereby reducing waste.

At least another aspect of the invention disclosed herein includes embodiments in which an intraocular gas injector design allows for automated operation during at least some stages of operation, thereby reducing the likelihood of errors in achieving appropriate concentration levels. For example, in some known intraocular gas injector devices and procedures, such as in conventional syringes, a nurse or other operating room personnel must physically measure the amount of gas contained within the syringe during the first stage of operation. In situations where small changes in volume can result in significant changes in concentration, small errors in physical measurement can result in an inappropriate concentration being achieved within the syringe after all stages of operation are completed. Therefore, an intraocular gas injector that automatically measures volume during the first stage and/or any other stage can reduce the likelihood of an inappropriate concentration being achieved within the syringe.

At least another aspect of the invention disclosed herein includes embodiments in which an intraocular gas injector is designed to have a canister positioned within the injector, wherein the canister can be independently filled prior to incorporation into the injector, thereby reducing manufacturing costs. Thus, for example, an intraocular gas injector device may include a separate canister positioned within the injector body.

At least another aspect of the invention disclosed herein includes embodiments in which an intraocular gas injector design may include a storage member having an internal valve mechanism, thereby reducing the manufacturing cost of the injector. For example, in some designs, the device may use multiple pressure regulating systems (such as check valves, etc.) incorporated into components of the device to regulate the pressure within the device and control the operation of the device. Incorporating pressure regulating systems into components of the device may result in increased manufacturing costs for these components. Therefore, if the manufacturing cost of the internal valve mechanism within the storage member is lower than the manufacturing cost of valves incorporated into other components of the device, then repositioning the valve relative to the storage member may help reduce the manufacturing cost of the device.

At least one aspect of the invention disclosed herein includes embodiments in which an intraocular gas injector design may include an interlock mechanism configured to control the movement of an actuator switch, thereby reducing the possibility of incorrect operation of the injector. For example, in some designs, the device may include an actuator switch that can control, for example, the operation of the device, such as controlling the opening and closing of a pressurized chamber within the device. In some instances, a user can use the actuator switch to reopen the pressurized chamber within the device if opening results in the receipt of an inappropriate concentration. An interlock mechanism configured to control the movement of the actuator switch can help reduce the possibility of incorrect operation of the injector.

At least one aspect of the invention disclosed herein may include an embodiment in which an intraocular gas injector design, when connected to an external pressurized chamber, may allow for automation of at least some stages of operation, thereby reducing potential errors in achieving the proper concentration level. For example, in some known intraocular gas injector devices and procedures, such as in a conventional syringe, a nurse or other operating room personnel may connect an external gas tank to a syringe and repeatedly fill and release gas within the syringe to ensure that the syringe contains primarily gas from the tank. During these refill and release cycles, another person may need to open and close a valve on the external gas tank. Thus, for example, an intraocular gas injector may allow for the attachment of an external pressurized chamber and automatically reach a set volume and release gas so that the syringe contains primarily gas from the external pressurized chamber.

This summary is provided to introduce a selection of concepts in a simplified form that will be further described in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 shows a first embodiment of a gas mixing device.

FIG. 2A is a second embodiment of a gas mixing device shown in an initial stage of operation.

FIG. 2B is a second embodiment of a gas mixing device shown in a first stage of operation.

FIG. 2C is a second embodiment of a gas mixing device shown in a second stage of operation.

FIG. 2D is a second embodiment of a gas mixing device shown in a third stage of operation.

3 is an exploded view of the components of a second embodiment of a gas mixing device.

FIG. 4 is a perspective view of a measurement control system and an actuation system of a second embodiment of a gas mixing device.

5A is a perspective view of a measuring dial of a second embodiment of a gas mixing device.

5B is a cross-sectional view of the metering scale of the measurement control system in FIG. 4 .

FIG. 6 is a perspective view of a plunger body of the measurement control system in FIG. 4 .

FIG. 7 is a perspective view of the actuation system in FIG. 4 .

8A is a cross-sectional view of the measurement control system and actuation system of FIG. 4 , in a first or “off” position.

8B is a cross-sectional view of the measurement control system and actuation system of FIG. 4 , in a second or “on” position.

9 is a side view of an embodiment of an actuation system, a pressurization chamber, and a first pressure regulation system of a second embodiment of a gas mixing device.

10 is a cross-sectional view of the actuation system, pressurization chamber, and first pressure regulation system of FIG. 9 , in a first position.

11 is a cross-sectional view of the actuation system, pressurization chamber, and first pressure regulation system of FIG. 9 , in a second position.

12 is a cross-sectional view of components of a second embodiment of a gas mixing device including a mixing chamber and a second pressure regulation system.

13 is an enlarged cross-sectional view of the mixing chamber and the second pressure regulating system of FIG. 12 .

14 is an enlarged cross-sectional view of the mixing chamber and second pressure regulating system of FIG. 12 with additional attachments.

15A is a perspective view of a metrology dial of an embodiment of a measurement control system.

15B is a cross-sectional view of a metrology scale of an embodiment of a measurement control system.

16 is a perspective view of a plunger body of an embodiment of the measurement control system.

17 is a perspective view of components of an embodiment of an actuation system.

18 is a cross-sectional view of the measurement control system and actuation system in a first, "initial" or "pre-actuated" position, illustrating the operation of the interlock mechanism.

19 is a cross-sectional view of the measurement control system and actuation system in a second or "on" position, illustrating the operation of the interlock mechanism.

20 is a cross-sectional view of the measurement control system and actuation system in a third or "off" position, illustrating the operation of the interlock mechanism.

21 is a cross-sectional view of the measurement control system and actuation system in a first, "initial" or "pre-actuated" position, illustrating the operation of the latch.

22 is a cross-sectional view of the measurement control system and actuation system in a second or “open” position, illustrating the operation of the latch.

23 is a cross-sectional view of the measurement control system and actuation system in a third or "off" position, illustrating the operation of the latch.

24 is an enlarged view of an embodiment of an actuation system, a pressurization chamber, and a storage member pressure regulation system.

25A is a cross-sectional view of the embodiment of the actuation system, pressurization chamber, and storage member pressure regulation system of FIG. 24 , in a first, “initial” or “pre-actuated” position.

25B is an enlarged view of an embodiment of the actuation system, pressurization chamber, and storage member pressure regulation system of FIG. 25A .

26A is a cross-sectional view of the embodiment of the actuation system, pressurization chamber, and storage member pressure regulation system of FIG. 24 , in a second or “open” position.

26B is an enlarged view of an embodiment of the actuation system, pressurization chamber, and storage member pressure regulation system of FIG. 26A .

27A is a cross-sectional view of the embodiment of the actuation system, pressurization chamber, and storage member pressure regulation system of FIG. 24 , in a third or “closed” position.

27B is an enlarged view of an embodiment of the actuation system, pressurization chamber, and storage member pressure regulation system of FIG. 27A .

28 is an enlarged view of an embodiment of the actuation system, pressurization chamber, and storage member pressure regulation system of FIG. 25A , showing an embodiment of the storage member in greater detail.

29 is an enlarged view of an embodiment of the actuation system, pressurization chamber, and storage member pressure regulation system of FIG. 26A , showing an embodiment of the storage member in greater detail.

30 is a cross-sectional view of an embodiment of a syringe body and syringe pressure regulation system.

DETAILED DESCRIPTION

The detailed description below is merely illustrative in nature and is not intended to limit the embodiments of the present application or the subject matter and the uses of these embodiments. As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any embodiment described as an example in this application is not necessarily to be construed as preferred or superior to other embodiments. Furthermore, no one is intended to be bound by any express or implied theory presented in the preceding technical field, background technology, summary of the invention, or the following detailed description.

Certain terms are used in the following description for reference purposes only and are not intended to be limiting. For example, terms such as "above," "below," "above," and "below" refer to directions in the accompanying drawings to which reference is made. Terms such as "proximal," "distal," "front," "behind," "rear," and "to the side" describe the orientation and/or position of parts of a component within the same arbitrary framework to which reference is made, as further clarified by reference to the text and associated drawings showing the component in question. These terms may include the terms specifically mentioned above and their derivatives, as well as terms of similar meaning. The terms "first," "second," and other such numerical terms referring to structures are the same as above.

As used herein, the terms "front" and "distal" refer to the part of the target device that is positioned away from the user of the device (e.g., a surgeon) during an injection procedure. As used herein, the terms "rear" and "proximal" refer to the part of the device that is positioned closer to the user of the device (e.g., a surgeon) during an injection procedure.

Device for mixing two gases

1 , an embodiment of a gas mixing device 10a may include a measurement and control system 110a, an actuation system 210a, and a mixing system 310a configured to produce a mixture of two or more gases having a desired concentration ratio. The mixing system 310a may include a pressurizing chamber 410a and a mixing chamber 510a.

The mixing system 310a may also include a pressure regulation system to enhance the operation of the mixing system 310a. In some embodiments, the mixing system 310a additionally includes a first pressure regulation system 610a and a second pressure regulation system 710a.

The measurement and control system 110a can be in the form of a metering mechanism operably coupled to any and all devices included in the mixing system 310a to control specific aspects of the devices included therein. In some embodiments, the measurement and control system 110a can be a variable and user-operable device, thereby allowing a user of the gas mixing apparatus 10a to modify certain aspects of the device. The actuation system 210a can be operably coupled to the pressurization chamber 410a to actuate the operation of the devices and initiate mixing of the gases within the mixing system 310a.

The pressurized chamber 410a may contain at least one of the two or more gases to be mixed in the mixing system 310a. In some embodiments, the pressure of the gas contained in the pressurized chamber 410a may be higher than the pressure of the surrounding ambient conditions. In addition, the pressurized chamber 410a may contain a concentration of gas that is different from the concentration in the atmosphere. The pressurized chamber 410a may be configured to be in fluid communication with the first pressure regulating system 610a. In other embodiments, the pressurized chamber 410a may be in direct fluid communication with the mixing chamber 510a. The pressurized chamber 410a may be configured to be internally contained within the syringe device. The pressurized chamber 410a may also be configured to be located external to the syringe device. The first pressure regulating system 610a may be configured to maintain a preset pressure difference between the pressurized chamber 410a and the mixing chamber 510a. The mixing chamber 510a may be configured to receive gas from the pressurized chamber 410a directly or via the first pressure regulating system 610a. In some embodiments, the mixing chamber 510a can also be configured to receive a second gas to be mixed from outside the mixing system 310a (such as an external gas container or the atmosphere). The mixing chamber 510a can be configured to be in fluid communication with the second pressure regulating system 710a at the outlet of the mixing chamber 510a. In other embodiments, the mixing chamber 510a can be in direct fluid communication with the atmosphere at the outlet of the mixing chamber. Embodiments of these subsystems are described below.

In some embodiments, the measurement and control system 110a is configured to control the concentration of the gases within the gas mixing device 10a. In some embodiments, the measurement and control system 110a is operably coupled to the mixing system 310a. Preferably, the measurement and control system 110a is operably coupled to the pressurized chamber 410a or the mixing chamber 510a, allowing the measurement and control system 110a to modify variable aspects of the pressurized chamber 410a and/or the mixing chamber 510a. In some embodiments, the measurement and control system 110a can control characteristics such as (but not limited to) the volume of gas contained within the mixing chamber 510a. Other characteristics that the measurement and control system 110a can control, such as pressure, are also contemplated. Preferably, the measurement and control system 110a is variable, allowing a user to select a desired concentration ratio of the gases that can be discharged from the gas mixing device 10a. Advantageously, this allows a user to achieve a wide range of desired concentration ratios using only a single gas mixing device 10a. Thus, the measurement control system 110a may include user-operable switches (such as dials) that change the operation of components within the mixing system 310a (such as the pressurizing chamber 410a, the mixing chamber 510a, the first pressure regulation system 610a, and the second pressure regulation system 710a).

The pressurized chamber 410a is configured to store one or more gases in the internal space of the pressurized chamber 410a for a period of time before the two or more gases are mixed in the gas mixing device 10a. The conditions in the internal space are configured to be different from atmospheric conditions, and thus the internal space should generally reduce the release of the gas to the outside of the internal space or reduce the entry of non-stored gas into the internal space before the mixing of the two or more gases is performed.

In some embodiments, the one or more gases in the interior space are at a higher pressure than the surrounding atmospheric conditions. Furthermore, the one or more gases may be present at a concentration different from that of the surrounding atmospheric conditions. In some embodiments, the interior space may be divided into separate subsections or sections for holding the one or more gases. Thus, these separate sections of the interior space may hold gases at different pressures and/or concentrations.

In some embodiments, the gas may also be positioned within distinct structural units within the interior space. Such structural units can be used to more effectively reduce the release of stored gas and/or reduce the ingress of non-stored gas. In some embodiments, the stored gas is pre-loaded into the pressurized chamber 410a from the time of manufacture. In other embodiments, it is contemplated that the contents of the pressurized chamber 410a may be loaded by the user of the gas mixing device 10a. For example, the stored gas may be contained in a removable cartridge that advantageously facilitates the displacement of the gas.

In some embodiments, the actuation system 210a is configured to actuate the operation of the gas mixing device 10a and initiate the process of mixing two or more gases in the mixing system 310a. Thus, the actuation system 210a is operatively coupled to the mixing system 310a and may be coupled to both the mixing chamber 310a and the pressurization chamber 410a. The actuation system may cause the pressurization chamber 410a to actuate and release the gas contained therein into the mixing chamber 510a. In some preferred embodiments, the actuation system 210a may cause the pressure within the pressurization chamber 410a to increase, causing the first pressure regulating system 610a to be actuated, thereby allowing fluid to flow from the pressurization chamber 410a into the mixing chamber 510a. The actuation system 210a may include a device configured to actuate a separate portion of the pressurization chamber 410a that is held at a higher pressure than the remainder of the pressurization chamber 410a, thereby increasing the pressure within the separate portion of the pressurization chamber 410a. In a preferred embodiment, the actuation system 210a can cause a seal within the mixing chamber 510a to rupture, thereby increasing the pressure throughout the pressurized chamber 410a. In this embodiment, the actuation system 210a can include a piercing device capable of rupturing the seal. The use of the actuation system 210a provides advantages by allowing the gas mixing device 10a to be pre-filled and safely stored prior to use.

The actuation system 210a can also be operably coupled to the mixing chamber 510a, allowing a user to manually change certain aspects of the device. In some embodiments, the actuation system 210a can be used to change the volume of the mixing chamber 510a. The actuation system 210a can also be used to change the pressure of the mixing chamber 510a.

In some embodiments, the first pressure regulating system 610a is configured to serve as a separation mechanism between the pressurizing chamber 410a and the mixing chamber 510a. The first pressure regulating system 610a can be actuated when a predetermined pressure differential between the pressurizing chamber 410a and the mixing chamber 510a is reached. In some preferred embodiments, the first pressure regulating system 610a may include at least one valve assembly. When the pressure within a portion of the pressurizing chamber 410a is higher than the pressure within the mixing chamber 510a, the valve assembly can open. The valve assembly can be a check valve, a flap valve, a non-return valve, or a one-way valve. These valves may also include ball check valves, diaphragm check valves, rotary check valves, shut-off check valves, lift check valves, straight-through check valves, and duckbill valves. Other pressure regulating mechanisms may also be used. Furthermore, it is contemplated that the first pressure regulating system 610a may be actuated by methods other than a pressure differential within the system 610a.

In some embodiments, the mixing chamber 510a is configured to serve as a space in which two or more gases can be mixed to obtain a desired concentration ratio of the gases. Depending on the use of the actuating mechanism, the mixing chamber 510a may be of variable and adjustable volume. The mixing chamber 510a may receive gas only from the pressurized chamber or receive gas already present in the mixing chamber 510a for mixing. The mixing chamber 510a may also receive gas from an auxiliary source. In some embodiments, the mixing chamber 510a may receive air from the atmosphere to mix with the gas received from the pressurized chamber 310a and/or the gas already present in the mixing chamber 510a.

In some embodiments, the second pressure regulating system 710a is configured to serve as a separation mechanism between the mixing chamber 510a and the surrounding atmosphere. When a preset pressure difference between the mixing chamber 510a and the surrounding atmosphere is reached, the second pressure regulating system 710a can be actuated. In some preferred embodiments, the second pressure regulating system 710a may include at least one valve assembly. When the pressure within the mixing chamber 510a is higher than the pressure of the surrounding atmosphere, the valve assembly can open. The valve assembly can be a check valve, a flap valve, a non-return valve, or a one-way valve. These valves may also include ball check valves, diaphragm check valves, rotary check valves, shut-off check valves, lift check valves, straight-through check valves, and duckbill valves. Other pressure regulating mechanisms may also be used. In addition, it is contemplated that the second pressure regulating system 710a can be actuated by other methods other than the pressure difference within the system 710a.

Operation Overview

Referring to Figures 2A-2D , the operation of an embodiment of a gas mixing device 10b is illustrated. Referring to Figure 2A , the device 10b may be in an initial stage, with the actuation system 210b in a first, or "off," position. At this point, a user of the device may use the measurement and control system 110b to select a desired concentration of gas for the injectable volume. Once selected, the user may move the actuation system 210b to a second, or "on," position, thereby activating the system and initiating the mixing process.

As shown in FIG2B , during the first operating phase, the gas contained in the pressurized chamber can be released, and in an embodiment comprising a first pressure regulating system, the first pressure regulating system can be opened in response to the pressure change in the pressurized chamber. Therefore, fluid can flow from the pressurized chamber into the mixing chamber 510b, thereby causing the volume of the mixing chamber 510b to increase. However, due to the components of the measurement and control system 110b, the mixing chamber 510b can reach a first volume but cannot expand beyond this first volume. The first volume can be set based on the desired concentration of the injectable volume. During the first operating phase, excess gas can also be discharged from the mixing chamber 510b via the second pressure regulating system 710b. Once the mixing chamber reaches this first volume, the first operating phase is completed and the second operating phase begins.

During the second operating phase, the mixing chamber 510b can be maintained at the first volume while the pressure within the mixing chamber 510b is relieved from the system via the second pressure regulating system 710b. Overfilling the mixing chamber 510b with the desired gas and then venting the gas helps ensure that a significant amount of atmospheric gas within the mixing chamber 510b (which may be contained within the mixing chamber 510b prior to actuation) is substantially purged from the mixing chamber 510b and replaced with the gas initially contained within the pressurized chamber. Once the pressure within the mixing chamber 510b has reached a set value based on the configuration of the second pressure regulating system 710b, venting of the gas within the mixing chamber 510b is stopped and the second operating phase is complete.

As shown in FIG2C , during the third stage of operation, an accessory 760 may be added to the system, which forces the second pressure regulation system 710b to remain open. This accessory may be a filter that removes bacteria to sterilize air, an infusion catheter, or a syringe needle. Opening the second pressure regulation system 710b causes the gas within the mixing chamber 510b to reach ambient pressure. Once a sufficient amount of time has passed since the gas reached ambient pressure, the user can set the actuation system 210b to the first, or "off," position, thereby unlocking the measurement and control system 110b. The user can then manually expand the volume of the mixing chamber 510b to an injectable volume. In some embodiments, once the injectable volume is reached, the measurement and control system 210b can stop expanding the volume of the mixing chamber 510b. Once the third stage is complete, the accessory can be removed, allowing the second pressure regulation system 710b to isolate the mixed gas from the surrounding atmosphere to reduce or prevent dilution of the mixed gas.

An important advantage of the operation of device 10b is that whole process can be performed by the single individual (singleindividual, single person) in the aseptic zone.And this process is automated substantially, thereby makes the user only need to be arranged into suitable setting by measurement control system 210b and device 10b will automatically perform the major part of remaining steps.And, the step automatically performed by device 10b is normally the most error-prone step (such as, measuring suitable volume to realize the concentration of expectation), thereby greatly reduces the risk of the incorrect concentration of gas in the volume that obtains injectable.Comprise second pressure regulating system 710b can reduce or prevent the unfavorable dilution of surrounding atmosphere to gas at the end of second operating stage and the 3rd operating stage.

In other embodiments, fewer or more operating phases may be performed. In some embodiments, only a single operating phase may be performed. For example, the pressurized chamber 410a may contain a gas at a preset concentration level. During a single operating phase, the user may actuate the device 10b so that the gas or fluid flows from the pressurized chamber 410b into the second chamber (e.g., the mixing chamber 510a) until the pressurized chamber reaches the configured volume. A pressure regulating system may also be used to discharge or exhaust the gas or fluid until the desired pressure is achieved in the pressurized chamber. After the gas is exhausted, the device 10b may be ready for use. It will be apparent to those skilled in the art that in this embodiment, in fact, little or no mixing is performed.

System Overview

3 , components of an embodiment of a gas mixing device 10b are shown, including a measurement and control system 110b, an actuation system 210b, a pressurization chamber 410b, a mixing chamber 510b, a first pressure regulation system 610b, and a second pressure regulation system 710b. The measurement and control system 110b may include a metering scale 120 and a plunger body 160 that can be inserted into the metering scale 120. The actuation system 210b may include an actuation rod 220 and an actuation switch 260. The actuation system 210b can be operably coupled to the measurement and control device 110b to control the operation of the gas mixing device 10b. The actuation system 210b can be inserted into the plunger body 160.

The pressurized chamber 410b may include a housing 420, a canister 436 containing gas, a release mechanism 444 for releasing the gas contained in the canister 436, a filter 448 that reduces the amount of non-gas or bacterial matter that flows out of the housing 420, and a piston seal 460. The mixing chamber 510b may include a syringe body 520. The first pressure regulating system 610b may include a valve body and associated valve components. The second pressure regulating system 710b may also include associated valve components.

Measurement control systems and actuation systems

4 , an embodiment of a combined measurement control system 110b and actuation system 210b is shown. The measurement control system 110b may include a metering dial 120 and a plunger body 160. The actuation system may include an actuation rod 220 (shown in FIG. 7 ) and an actuation switch 260.

5A and 5B , an embodiment of a metering dial 120 of a gas mixing device 10b is shown, which is configured to allow a user of the device 10b to selectively change the concentration of an injectable volume. The metering dial 120 includes at least two structural components, namely, a metering body 122 and a metering cap 124 that can be coupled to the metering body 122 to allow the metering dial 120 to be reversibly attached to another component of the device 10b. Advantageously, this facilitates assembly of the device and, in some reusable embodiments, facilitates disassembly for resterilization. In some embodiments, the metering cap 124 can be reversibly attached to the metering body 122 using fasteners such as screws, rivets, clips, and other fastening mechanisms known in the art. The attachment of the metering cap 124 to the metering body 122 can form an annular groove 126 and an annular lip 128 to enable the metering dial 120 to be attached to another component of the device 10b. For example, the annular groove 126 and the annular lip 128 may correspond to the flange 526 positioned on the syringe body 520.

The metering body 122 may include a generally cylindrical member 130 having a flange 132 located at a top end and a channel 134 located approximately at the center of the cylindrical member 130 and extending along the entire length of the metering body 122. Because the metering body 122 is configured to control the concentration of gas within the injectable volume, the metering body 122 may include a metering indicator 136 disposed along a surface that is viewable by a user of the device 10b when fully assembled. In the illustrated embodiment, the metering indicator 136 is positioned on the top surface of the flange 132, although any user-viewable location may be used. The metering indicator 136 may provide information to the device user regarding the operation of the device 10b. In the illustrated embodiment, the metering indicator 136 displays a numerical range of 18, 19, 20, 21, and 22, corresponding to the concentration of sulfur hexafluoride ( _SF6 ) that would be produced within the injectable volume if the device 10b were actuated. As will be apparent to one skilled in the art, the range used may depend on the gas used and the application for the gas. Moreover, in some embodiments, the range can be further divided to provide enhanced control over the desired concentration.

The meter body 122 can have slots 138, guides 140, and variable stops 142 corresponding to the meter indicators 136. In the illustrated embodiment, the meter body 122 has five spaced slots 138 positioned along the inner surface of the passage 134, corresponding to the five integer values described above. In other embodiments, the meter body 122 can have fewer or more slots than the number of values provided by the meter indicator 136.

Corresponding to each groove 138 is a variable stop 142 extending inwardly from the groove 138. As described above, these variable stops 142 may extend a set distance from the top surface of the flange 132 toward the bottom end of the tubular body 130. In some embodiments, the variable stops 142 need not extend from the top surface, but rather may be small protrusions at a set distance toward the bottom end of the cylindrical member 130. These variable stops 142 are configured to interact with components housed in the plunger body 160 (such as the latch 228) or the plunger body 160 itself to control the expansion volume of the mixing chamber 510b during the first and second operating stages by limiting the rearward extension of the plunger body 160 during these stages (see FIG. 2B ). Thus, the variable stops 142 extend different distances depending on the concentration to which they correspond. For example, a concentration of 21% extends a shorter distance than a concentration of 20%. Thus, when a 21% concentration is selected, the plunger body 160 may be allowed to extend rearward a greater distance, thereby allowing for greater expansion of the mixing chamber 510b during the first stage of operation. It is therefore apparent that the variable stop 142 is used to control the first expansion volume in the first stage of operation.

The guide rails 140 extending inwardly from the inner surface of the channel 134 are located on both sides of the groove 138. In some embodiments, the guide rails 140 extend inwardly from the inner surface of the channel 134 a distance greater than the variable stop 142. The guide rails 140 can be configured to prevent the device 10b from switching to different concentration values when the device 10b is actuated. This is particularly important for applications where a specific concentration of gas is required and any slight change in this value can have a significant adverse effect. In the illustrated embodiment, the guide rails 140 are configured to fully reduce the possibility of the plunger body 160 rotating to different variable stops 142 during the first two operating stages. In certain embodiments, if a frequently variable metering device is desired, these guide rails can be removed. In this embodiment, the variable stop 142 can have a ramp shape rather than having multiple steps.

In addition, metering body 122 may include a ratchet pawl 144 along the inner surface of passage 134, extending inwardly toward the center of passage 134. Ratchet pawl 144 may be hinged and configured so that ratchet pawl 144 can be movably deformed and provide resistance during deformation. Ratchet pawl 144 may correspond to features positioned on plunger body 160 so as to correctly position relative to the selected concentration. In addition, the mechanism may provide contact feedback to the user of the device to indicate that appropriate alignment has been completed. This contact feedback may advantageously reduce the possibility of actuation in an inappropriate orientation. Other types of feedback mechanisms and alignment mechanisms may also be used.

6 , an embodiment of a plunger body 160 is shown, comprising a generally tubular frame 162, a handle 164 at one end of the plunger body 160, a selector ring 166 between the tubular frame and the handle, and a channel 168 located in the center of the tubular frame 162 and extending the entire length of the plunger body 160. The tubular frame 162 is configured to translate slidably and partially slidably within the channel 134 of the metering dial 120. The tubular frame 162 has a retaining mechanism 170 in the form of a clamp that is hingedly attached to the tubular frame 162. The retaining mechanism 170 can be configured to retain components (such as the housing 420) of the pressurized chamber 410 b. The retaining mechanism 170 is advantageous in allowing the components to be attached without the use of tools, thereby simplifying the assembly process of the entire device. Additionally, the retaining mechanism 170 can also be configured so that the component can be removed from the tubular frame 162, thereby allowing for reuse of the device 10b, or in other embodiments that allow for reuse of the device 10b, facilitating the resterilization process if such a process is used on the device. Other types of retaining mechanisms can also be used in place of the clamps shown in the illustrated embodiment and can include fasteners such as screws.

Furthermore, the tubular frame 162 may include a guard 172 extending outward from the outer surface of the tubular frame 162. The guard 172 may extend a certain distance from the bottom end of the tubular frame 162 to the top end of the tubular frame 162. The guard 172 is configured to fit within the groove 138 and the guide rail 140 located along the inner surface of the passage 134 of the metering body 122. Thus, when the guard 172 is positioned between the guide rails 140, the plunger body 160 is prevented from rotating. Advantageously, this prevents the plunger body 160 from moving to different variable stops 142 after initiating the first operational phase, thereby reducing the risk of an inappropriate concentration within the injectable volume. The guard 172 is preferably sized so that when the plunger body 160 is fully inserted, the guard 172 is only slightly below the guide rail 140, allowing the plunger body 160 to freely rotate to different concentration values during the initial operational phase (see FIG. 2A ). However, because the guard 172 is only slightly below the rails 140, once extended a short distance, the guard 172 can be locked within the selected rail 140. This positioning advantageously allows the guard 172 to be locked immediately after the device 10b is actuated. Furthermore, the guard 172 preferably extends outward from the tubular frame 162 only a sufficient distance so that the guard can contact the rails 140, but not a sufficient distance so that the protective lens can contact the variable stop 142 positioned between the rails 140. Thus, this allows the guard 172 to be uninterrupted by the variable stop 142 during operation.

In addition, the tubular frame 162 can include a latch aperture 174 configured to allow a latch 228 positioned on the actuating rod 220 to protrude outward from the tubular frame 162. Preferably, the latch aperture 174 is centrally located above the topmost portion of the guard 172. As will be discussed in detail below, in a first, or "closed," position, the latch 228 cannot extend beyond the guard 172 and, therefore, cannot contact the variable stop 142 (see FIG8A). When in a second position, the latch 228 can extend outward from the tubular frame 162 beyond the guard 172 so that the latch 228 can contact the variable stop 140, thereby preventing further expansion of the plunger body 160 when the latch is in the second position (see FIG8B). In some embodiments, if the plunger body 160 is improperly oriented within the metering dial 120 during the initial stage of operation (shown in FIG. 2A ), the latch aperture 174 can be positioned such that the latch 228 can be prevented from extending outwardly into the second, or “open,” position by the guide track 140 of the metering dial 120. This can advantageously prevent the device 10b from being actuated when improperly oriented.

In addition, the tubular frame 162 may include ratchet grooves 176 in the form of cutouts located along its outer surface. The ratchet grooves 176 are configured to receive the ratchet pawls 144 of the metering body 122, thereby providing a mechanism for ensuring that the plunger body 160 is properly oriented within the metering body 122 by providing resistance to rotation when the ratchet pawl 144 is received within one of the ratchet grooves 176. Moreover, advantageously, at each point at which the ratchet pawl 144 is received within the ratchet grooves 176, the user of the device 10b may also receive tactile feedback when the plunger body 160 is improperly oriented within the metering body 120.

The selector ring 166 can be an annular protrusion extending from the outer surface of the tubular frame 162. Furthermore, the selector ring 166 can include a selector indicator 178, which can be in the form of a small protrusion positioned on the selector ring 166. The selector indicator 178 can correspond with the metering indicator 136 positioned on the metering body 122 to indicate the concentration level achieved when the plunger body 160 is oriented in that position. Advantageously, this system can provide the device user with easily visible information regarding the selected concentration level. Advantageously, the selector indicator 178 can be colored to facilitate use of the device 10b.

The handle 164 can extend radially from the longitudinal axis of the tubular frame 162 in two opposite directions. The handle 164 can be shaped so that a user of the device 10b can contact the handle 164 and use it to further extend the plunger body 160 rearward and out of the device 10b or to further depress the plunger body 160 forward into the device 10b. In addition, the handle can include a pin hole 180 for receiving a coupling mechanism for the actuation switch 260. Thus, the actuation switch 260 can be rotated about the coupling mechanism to operate the actuation rod 220 positioned within the plunger body 160.

Referring to FIG7 , an embodiment of an actuation system 210 b including an actuation lever 220 and an actuation switch 260 is shown. The actuation lever 220 has a generally elongated body having an actuator pin 222 located at a first end, an actuator rod 224 located at a second end, and a latch-moving portion 226 positioned in a middle portion. The actuator pin 222 is configured to be received within the housing 420 of the pressurized chamber 410 b and, when in a second, or “open,” position, actuates the release of gas contained in the pressurized chamber. The actuator rod 224 is configured to abut against and emulate a contoured surface 262 of the actuator switch 260. Preferably, the actuator rod 224 is also shaped so that its cross-sectional profile matches the cross-sectional profile of the top portion of the channel 169 (shown in FIG8 ) positioned adjacent to the handle 164 of the plunger body 160. Preferably, the cross-sectional profile is generally non-circular so as to substantially prevent the actuator rod 220 from rotating within the passage 168 of the plunger body 160. The latch moving portion 226 is shaped so as to cause the latch 228 to translate as the latch 228 slidably translates along the latch moving portion 226 of the actuator rod 220. Thus, the latch 228 has a hole 230 having a cross-sectional shape similar to that of the latch moving portion 226.

The actuator switch 260 is configured to translate the actuator rod 220 through the plunger body 160 and through the housing 420 of the pressurized chamber 410b to actuate the release of the gas contained therein. Thus, the actuator switch 260 may be a cam having a wavy profile 262 along a surface configured to contact the actuator rod 224. The actuator switch may also have a hole 264 configured to receive a pin 266, thereby allowing the actuator switch 260 to rotate about the pin 266. In the illustrated embodiment, the actuator switch 260 is shown in a first, or "off," position. In this first position, the distance between the pin 266 and the contoured surface 262 in contact with the actuator rod may be a reduced distance, such that the actuator rod remains in the first, or "off," position. However, when rotated about pin 266 to a second, or "on," position, the distance between pin 266 and contoured surface 262 in contact with actuator rod 224 can be increased, thereby translating actuator rod 220 to a second, or "on," position further within housing 420 of pressurized chamber 410b. As discussed in greater detail below with reference to Figures 10 and 11, movement to the second, or "on," position can be used to release gas within pressurized chamber 410b. Actuator switch 260 can preferably be any type of switch capable of being retained in either the first or second position without requiring the user to hold the switch in that position. In the illustrated embodiment, a rotating lever is used. Other switches, such as screws, latches, spring-loaded pins, or any other switches known in the art, can also be used.

8A and 8B , diagrams illustrating the operation of the actuation system 210b are shown, including certain components of the measurement control system 110b and the actuation system 210b. As shown, the latch 228 is housed within the latch aperture 174, preventing the latch from translating toward the front or rear end of the plunger body 160. Therefore, when the actuator rod 220 translates in the forward or rearward direction, the latch 228 must follow the contour of the latch-moving portion 226 of the actuator rod 220. This provides the advantage of coupled movement of the latch 228 in the second position when the actuator switch 260, and thus the actuator rod 220, is in the corresponding second position. Furthermore, because the movement of the latch 228 is coupled to the movement of the other actuator switches 260 and the actuator rod 220, if the latch 228 is prevented from moving to the second position, the actuator switch 260 and the actuator rod 220 are also prevented from moving to the second position. It should be noted that, as described above, when in the second or "open" position, the latch 228 can protrude from the plunger body 160, thereby limiting extension of the plunger body 160, as shown in FIG. 8B.

Pressurized chamber and first pressure regulating system

9, an embodiment of some components of the actuation system 210b, the pressurized chamber 410b of the mixing system 310b, and the first pressure regulating system 610b of the mixing system 310b is shown. As shown, the pressurized chamber 410b can have a housing 420 with an annular groove 422 positioned near a first end of the housing 420. The annular groove 422 can be configured to receive a retaining mechanism 170 positioned on the plunger body 160. The housing can also have a piston seal 460 positioned at a second end of the housing 420. The piston seal 460 is configured to provide an airtight seal defining the mixing chamber 510b.

Referring to FIG. 10 , which is a cross-sectional view of pressurized chamber 410b and first pressure regulating system 610b, housing 420 has a generally cylindrical body with an annular groove 422 located at a first or rearward end and a conical or frusto-conical surface 424 located at a second or forward end, corresponding to the shape of piston seal 460. Furthermore, housing 420 may be shaped to include an annular protrusion 426 and an annular groove 428 configured to receive lip 462 of piston seal 460. This configuration helps ensure that piston seal 460 remains connected to housing 420 and forms a seal to prevent leakage of any gas contained within housing 420. Preferably, lip 462 of piston seal 460 fits tightly within annular groove 428 of housing 420 to provide an enhanced seal. Housing 420 generally encloses interior space 430, which may be partitioned into a first partition 432 and a second partition 434. A third compartment in the form of a structural unit, such as a canister 436, can be housed within the second compartment 434 of the housing 420. The canister can contain gas for mixing into the mixing chamber 510b. Providing the gas in the canister is advantageous because it facilitates manufacturing of the device 10b, as it allows the canister to be manufactured independently of the other components of the pressurized chamber 410b. In some embodiments where the device 10b is reusable, the canister can be replaced.

Canister 436 has a first or rearward end that contacts actuator pin 222 and a sealed second or forward end 437. Located at one end of canister 436 is a seal 438 that substantially reduces any gas leakage from first partition 432 to second partition 434. This helps reduce the likelihood of gas leaking out of actuator aperture 440 and outside of device 10b.

The housing may also include a biasing mechanism 442 (such as a spring) that applies a force to the seal in a direction away from the second end of the housing 420. In the illustrated embodiment, the biasing mechanism 442 is positioned within the first compartment 432. This reduces the possibility that the container canister 436 could move into the first compartment 432 without user actuation and potentially release the gas contained therein. Furthermore, the biasing mechanism 442 can also provide a counterforce to actuation, thereby preventing the user from accidentally actuating the device. Preferably, the biasing mechanism 442 is configured to exert sufficient force such that, after the first and second operating stages are completed and the actuation switch 160 is returned to the first or "off" position, the biasing mechanism 442 applies sufficient force to return the actuator rod 220 to its first or "off" position, thereby causing the latch 228 to return to its first or "off" position. Once the latch 228 returns to its first or "off" position, expansion of the plunger body 160 is no longer restricted and the third operating stage can begin. If the biasing mechanism 442 does not apply sufficient force to the actuator stem 220, entering the third stage of operation may become significantly more difficult.

The housing may also have a release mechanism 444 (such as a needle or guide tip as shown in this embodiment of the device 10b). Since the passage 446 extends axially through the release mechanism 444, the release mechanism 444 can be configured to pierce the sealed second end 437 of the container canister 436 to release the gas into the first partition 432 through the release mechanism 444. Due to the high pressure in the first partition 432, the first pressure regulation system 610b can open to allow the gas to vent to the front of the piston seal 460 and into the mixing chamber 510b. In some embodiments, a filter 448 can be positioned along the flow path to reduce the possibility of foreign matter entering the mixing chamber 510b. This is particularly important when the gas may be placed in an area that is highly sensitive to the presence of foreign matter, such as a body cavity. The presence of foreign matter can cause infection or other hazards. In some embodiments, the filter 448 can be configured to filter out bacteria to sterilize the air.

The piston seal 460 is configured to partially define the injectable volume of the mixing chamber 510b by forming a seal therewith. The piston seal 460 may have a generally cylindrical body having an annular protrusion 464 and a conical or frusto-conical surface 466 located at the forward end. The annular protrusion is configured to contact the inner surface of the mixing chamber 510b. In addition, the frusto-conical surface 466 may include a hole 468 centrally located about the cylindrical body, the hole being configured to receive components of the first pressure regulating system 610b. Furthermore, the body may also have an opening 470 defined by a lip 462 at the rearward end, the opening being configured to receive the housing 420.

Continuing with FIG. 10 , an embodiment of a first pressure regulation system 610b is shown in a first, or "closed," position. The first pressure regulation system 610b may include a valve body 620 including a plurality of apertures 622 at one end; a valve stem 624 extending through the valve body 620 and having a valve seat 626 at a rearward end configured to contact a biasing mechanism 628; and a valve head 630 at a forward end configured to contact a sealing ring 632. During operation, the biasing mechanism 628 applies a rearward biasing force against the valve seat 626, biasing the valve head 630 against the sealing ring 632 and the valve body 620, thereby reducing or preventing gas flow through the valve body 620 and ultimately into the mixing chamber 510b. Due to the orientation of the biasing mechanism 628, the first pressure regulation system 610b remains closed until the pressure within the pressurization chamber 410b exceeds a threshold. This threshold can be configured by varying the amount of force required to depress the biasing mechanism 628.

Referring to FIG11 , an embodiment of the first pressure regulating system 610b is shown in an "open" position during a first operating phase and a second operating phase. During these phases, the pressure within the pressurizing chamber 410b may exceed the pressure within the mixing chamber 510b. In some preferred embodiments, the pressure differential is significant, and due to this pressure differential, sufficient force is exerted on the valve member to overcome the biasing mechanism 628, thereby allowing gas to flow out of the valve body 620 and into the mixing chamber 510b.

The configuration for the first pressure regulation system 610b is advantageous due to the multiple operating phases of the device 10b. During the first operating phase and at least a portion of the second operating phase, the pressure differential causes the valve to remain open. However, once the pressure differential is insufficient to overcome the threshold, the valve remains in the closed position, thereby preventing any additional gas from flowing into the mixing chamber and potentially disrupting the calculated pressure/concentration.

With reference to Figure 12, the embodiment of the mixing chamber 510b that comprises the various parts of syringe body 520, second pressure regulating system 710b and system described above is shown.Syringe body 520 has cylindrical body, is positioned at the hole 522 of rear end and is positioned at the threaded nozzle 524 of front end.Syringe body also has the flange 526 that is configured to engage with metering device 120.Mixing chamber 510b can be limited by the inwall and piston seal 460 of syringe body 520.And syringe body can comprise indicator 528 along its outer surface, and described indicator corresponds to selected concentration.Advantageously, these indicators 528 can provide the visual confirmation of selected concentration to the user.

Referring to FIG. 13 , an embodiment of a second pressure regulating system 710 b is shown that includes a valve body 720, which may include a ball 722, a biasing mechanism 724, a valve seat 726, and a sealing mechanism 728. The second pressure regulating system 710 b may also include a second biasing mechanism 730 and a pin actuator 732. The valve body 720 can translate within an interior space 734 near the nozzle 524 of the syringe body 520. In some embodiments, due to the presence of the second biasing mechanism 730, the valve body 720 translates such that a flange 735 of the valve body 720 presses against an inner lip 736 of the nozzle 524. Furthermore, the biasing mechanism 724 can seal flow through the valve body 720 until sufficient force is applied to the ball 722 to overcome the biasing force. This can occur when the pressure differential between the mixing chamber 510 b and the atmosphere exceeds a threshold.

During operation, the second pressure regulating system 710b opens due to the increased pressure contained in the mixing chamber 510b during the first and second operating stages. Once the pressure difference is insufficient to cause the valve body 720 to open, the second operating stage is completed and the user can move on to the third operating stage.

Referring to FIG. 14 , an embodiment of a second pressure regulating system 710 b having an attachment 760 including a filter is shown. Attachment 760 has a first open end 762, a second open end 766, and a filter element 768 positioned between the first and second open ends. The first open end has a flange 764 configured to engage with threads on the interior of the threaded nozzle 524. Thus, gas can travel from the first open end 762 to the second open end 766 and advantageously be filtered in the process, thereby reducing the risk of any hazardous substances entering the mixing chamber 510 b. In some embodiments, the inner surface of the first open end 762 tapers as it moves toward the second open end 766, such that this shape corresponds to the shape of the valve body 720. As attachment 760 is threaded into the threaded nozzle 524, it engages with the valve body 720 and overcomes the biasing force of the second biasing mechanism 730, causing the valve body 720 to translate toward the rear end of the syringe body 520. This causes the ball 722 to engage the pin actuator 732, thereby causing the valve body 720 to open and allow the gas in the mixing chamber 510b to reach ambient pressure. This configuration is advantageous because it allows the mixing chamber 510b to further expand under ambient pressure while simultaneously filtering the air drawn into the mixing chamber 510b. Thus, the third operating phase can be performed in this position. Once the third operating phase is completed, the attachment 760 can be removed. Due to the force of the second biasing mechanism 730, the valve body 720 can be translated away from the pin actuator 732, so that the valve body 720 remains closed until the user decides to inject gas.

Implementation of the measurement control system and the actuation system

15 to 30 show further embodiments of components of the measurement control system of the apparatus.

Figures 15A and 15B show an embodiment of a metering dial 820 that is configured to allow the user of the device to select the concentration of the fluid for the volume of the injectable. Similar to other embodiments, the metering dial 820 may include two components, such as a metering body 822 and a metering cap 824 that is removably attached to the metering body 822. As with other embodiments of metering dials and similar metering devices (such as metering dial 120), advantageously, removable attachments can facilitate assembly of the device. Moreover, in some embodiments, removable attachments can allow disassembly so that the device can be reduced to independent components, so that some or all components of the device can be re-sterilized. As with other embodiments, the metering cap 824 can be reversibly attached to the metering body 822 using fasteners such as screws, rivets, clamps, and other fastening mechanisms known in the art. In other embodiments, the metering body 822 and metering cap 824 can be immovably attached using devices and methods such as adhesives or welding. This embodiment can provide the advantage of reducing the possibility of damage. The attachment of the metering cap 824 to the metering body 822 can form an annular groove and an annular lip, thereby enabling the metering dial 820 to be attached to another component of the device. In some embodiments, the annular groove and the annular lip can correspond to corresponding features (such as a flange and a lip) located on the syringe on which the metering dial 820 is disposed.

Continuing with reference to Figures 15A and 15B, the metering body 822 can include a generally cylindrical member 830 having a flange 832 positioned at the top of the metering body 822. The metering body 822 can include a channel 834 located approximately at the center of the cylindrical member 830 and extending throughout the metering body 822. In some embodiments, the generally cylindrical member 830 can be sized and shaped to be received within a channel of another component of a device. For example, in some embodiments, the metering body 822 can be received within a channel of a syringe to which the metering scale 820 is attached. In some embodiments, as shown in Figure 15A, the generally cylindrical member 830 can include other surface features, such as an increased diameter portion 831 that can potentially key to the device into which the cylindrical member is inserted.

As with other embodiments of a metering dial or similar metering mechanism, this embodiment may also include a metering indicator 836 positioned along a surface of the metering body 820. In the illustrated embodiment, the metering indicator 836 is positioned on the top surface of the flange 832, although any other observable location (such as along a peripheral portion of the flange 832) may be used. In the illustrated embodiment, the metering indicator 836 displays a numerical range of 18, 19, 20, 21, and 22 corresponding to the concentration of sulfur hexafluoride ( _SF6 ) that can be produced within the injectable volume of the assembly. As will be apparent to one skilled in the art, the range used may depend on the gas used and the application of the gas. In some embodiments, the range may be further divided to provide greater accuracy and control over the desired concentration.

As with other embodiments of metering dials and other metering mechanisms, the metering body 822 may have slots 838 corresponding to the metering indicator 836, guide rails 840, and variable stops. As more clearly shown in FIG. 15B , the metering body 822 may have five separate slots 838 located along the inner surface of the channel 834, corresponding to the five metering positions 18, 19, 20, 21, and 22. In other embodiments, the metering body 822 may have fewer or more slots than the number of values provided by the metering indicator 836. A variable stop may correspond to each slot 838, extending inwardly from the slot 838. These variable stops may extend from the top surface of the flange 832 to a set distance toward the bottom end of the generally cylindrical member 830. Those skilled in the art will appreciate that the variable stops need not extend from the top surface. For example, in some embodiments, the variable stops may be protrusions located a set distance from the bottom end of the tubular body 830.

The operation of the variable stop of the illustrated embodiment of the metering scale 820 can be similar to the operation of other embodiments of metering scales and metering mechanisms. The variable stop can be configured to interact with a component housed in the plunger body 860 (such as a latch 928) or a similar protruding structure to control the expansion of the chamber for the injectable volume during at least some stages of operation. In some embodiments, the variable stop can perform this task by limiting the rearward expansion of the plunger body 860 during different stages. Thus, the variable stop extends different distances depending on the concentration to which the stop corresponds.

Continuing with reference to Figures 15A and 15B, the two sides of the groove 838 can be defined by guide rails 840 extending inwardly from the inner surface of the channel 834. In some embodiments, the guide rails 840 can extend inwardly from the inner surface of the channel 834 a greater distance than the stop. The guide rails 840 can be configured to prevent the device from switching to different concentration values when actuated. In the illustrated embodiment, the guide rails 840 are configured to greatly reduce the possibility of the plunger body 860 rotating to different variable stops during at least the first two operating stages. In certain embodiments, if a constant variable metering device is desired, the guide rails 840 can be removed. In this case, other mechanisms can be used to prevent or otherwise greatly reduce the possibility of selecting different concentration values after the device is actuated.

As more clearly shown in FIG. 15B , the metering body 822 may further include notches, indentations, dimples, recesses, or similar structures 842 along the inner surface of the channel 834, positioned along the inner surface of the channel 834 opposite the groove 838 and the guide rail 840. In other embodiments, the notches 842 may be positioned at other suitable locations on the metering dial 820. These notches 842 may correspond to features positioned on other components of the device to form a ratchet mechanism. For example, the notches 842 may correspond to the ratchet mechanism 886 (shown in FIGS. 21-23 ) positioned on the plunger body 860. Advantageously, the ratchet mechanism may be configured to provide tactile feedback to the user when the plunger body 860 is rotated to a selected concentration. Thus, when actuating the gas assembly, the device user is less likely to accidentally position the plunger body 860 in an inoperable position. Furthermore, the ratchet mechanism may also provide a threshold resistance to rotation from one concentration to a second concentration. In this embodiment, the ratchet mechanism may thus advantageously reduce the likelihood of accidental rotation from one concentration to a second concentration. Other types of feedback mechanisms and alignment mechanisms may also be used to provide tactile feedback.

16 , an embodiment of a plunger body 860 is shown that may include a generally tubular frame 862, a handle 864 located at one end of the plunger body 860, a selector member 866 located between the tubular frame and the handle, and a passage 868 located at the center of the tubular frame 862 that extends through the entire length of the plunger body 860 or through at least a portion of the length of the tubular frame 862. The tubular frame 862 may be configured to slidably translate and slidably rotate within the passage of a metering dial.

The tubular frame 862 may include retaining wings or clamps 870 positioned at the end opposite the handle 864. As shown in the illustrated embodiment, the retaining wings 870 may be partially cylindrical protrusions separated by two or more cutouts or slits 871. Thus, depending on the material used, the retaining wings 870 may flex outward when the component is received within the channel 868. In some embodiments, each retaining wing 870 may include a semi-annular lip along its inner surface that corresponds to the annular groove of the component inserted within the channel 868. For example, in some embodiments, the semi-annular lip may correspond to the annular groove 1024 positioned on the second housing member 1022 (see FIG. 24 ). Thus, the retaining wings 870 may allow for snap-fit assembly of the various components of the device, facilitating assembly and also allowing for disassembly for reuse and/or resterilization. Other fastening mechanisms and methods may also be used to attach the components to the plunger body 860, including fasteners, such as screws, adhesives, welding, and other similar mechanisms and processes known in the art.

Continuing with reference to FIG16 , the tubular frame 862 can include a guard 872 extending outwardly from the outer surface of the tubular frame 862. In some embodiments, the guard 872 can extend a certain distance from the bottom end of the tubular frame 862 toward the top end of the tubular frame 862, such as, for example, extending adjacent to the latch hole 874. In other embodiments, as shown in FIG16 , the guard 872 can be sized so as not to extend to the end surface of the tubular frame 862, but rather only to the cutout 871 of the retaining wing 870. Similar to other embodiments of the plunger body (such as the plunger body 160), the guard 872 can be configured to fit within the grooves and guides of the metering scale. In other embodiments, other types of metering devices can be used and the guard 872 can be configured to correspond to similar structural features on the device.

When the guard 872 is positioned between the guide rails 840, it can prevent or significantly reduce the possibility of rotation of the plunger body 860 after actuation. This advantageously prevents or reduces the possibility of rotation of the plunger body 860 during the operational phase, which could result in an erroneous concentration of fluid within the injectable volume. The guard 872 can be sized so that when the plunger body 860 is fully inserted into the passageway 834, the guard 872 is slightly below the guide rails 840, thereby allowing the plunger body 860 to freely rotate when in the first, "initial," or "pre-actuated" position to select different concentration values. However, because the guard 872 is only slightly below the guide rails 840, once extended a short distance, the guard 872 can be positioned between the selected guide rails 840. Advantageously, this positioning allows the guard 872 to be locked immediately after the device is actuated. Furthermore, the guard 872 may extend outwardly from the tubular frame 860 only a sufficient distance to contact the rails 840 , without extending outwardly sufficiently to cause contact with a variable stop or similar feature positioned between the rails 840 .

16 , the tubular frame 862 may include a latch aperture 874 configured to allow a latch 928, positioned on the actuation rod 920 and housed within the channel 868, to protrude outwardly from the tubular frame 862. As shown in the illustrated embodiment, the latch aperture 874 may be located only centrally above the topmost portion of the guard 872. In other embodiments, the latch aperture 874 may also be located at different locations along the tubular frame 862 and may include more than one latch aperture if multiple latches are used.

As described in greater detail below, in a first, "initial" or "pre-actuated" position, the latch 928 can be sized so as not to extend beyond the guard 872 and thereby not contact a variable stop or similar structure. When in a second, or "open" position, the latch 928 can be extended outwardly from the tubular frame 862 beyond the guard 872 so that the latch 928 can contact a variable stop or similar structure, thereby preventing or significantly reducing the likelihood of further expansion of the plunger body 860 when the latch is in the second position. As with other embodiments of the plunger body 860, in some embodiments, the latch aperture 874 can be positioned such that, if the plunger body 860 is improperly oriented within the metering dial 829 during the initial, or "pre-actuated" phase of operation, the latch 928 can be prevented from extending outwardly to the second, or "open" position by the guide rail 840 of the metering dial 820. Moreover, similar to other embodiments of the latch mechanism, the likelihood of a user being able to operate the activation switch 960 is also prevented or at least greatly reduced, thereby preventing or greatly reducing the likelihood of a user activating the device when the device is in an inoperable position.

The selector member 866 can be a protrusion extending from the outer surface of the tubular frame 862. The selector member 866 can also include a selector indicator 876 in the form of a small protrusion positioned on the selector ring 866. The selector indicator 876 can correspond to the metering indicator 836 positioned on the metering body 822 to indicate the concentration level that will be achieved when the plunger body 860 is oriented in that position upon actuation.

Continuing with FIG16 , the handle 864 can extend radially in both directions from the longitudinal axis of the tubular frame 862. The handle 864 can be configured so that a user can grasp the handle 864 and use it to further extend the plunger body 860 rearward, for example, to increase the volume contained within the device, or to further depress the plunger body 860 forward, for example, to decrease the volume contained within the device and eject the injectable volume. The handle 864 can also include a pin hole 878 for receiving a coupling mechanism, such as a coupling pin, for the actuation switch 960. Thus, the actuation switch 960 can be rotated about the coupling mechanism to operate the actuation rod 920, which can be positioned within the plunger body 960.

18-20 , the operation of the interlock mechanism will be described in greater detail. The handle 864 may further include a recess 880 configured to receive the actuator switch 960. The recess 880 may be sized such that, when the actuator switch 960 is in the third or "off" position, the actuator switch 960 is fully received within the recess 880. Furthermore, the handle 864 may further include an interlock aperture 882 and an interlock channel 884 configured to receive the interlock member 970 of the interlock mechanism.

Referring to FIG. 17 , an embodiment of an actuation system that can be used to control the operation of a device is shown. The actuation system may include an actuation rod 920 and an actuation switch 960. As shown in the illustrated embodiment, the actuation rod 920 may include an actuator body 922 having a generally cylindrical shape. The actuator body 922 may be configured to extend through a portion of the passage 868 of the plunger body 860. In other embodiments, the actuator body 922 may be elongated or shortened depending on the length of other components accommodated within the passage 868. In some embodiments, the actuator body 922 may have other cross-sectional shapes, such as circular, oval, elliptical, quadrilateral, or other polygonal shapes. Furthermore, the cross-sectional shape of the actuator body 922 may differ along different portions of the actuator body 922. For example, as shown in the illustrated embodiment, the actuator body 922 may have a circular cross-sectional shape along a first portion of the actuator body 922 and a "+" cross-sectional shape along a second portion. Similar to other embodiments of the actuator lever, the actuator body 922 can be configured to abut and emulate a contoured surface 962 of the actuator switch 960 located at a first end of the actuator body 922. In some embodiments, due to the presence of the contoured surface 962, the actuator body 922 can translate within the channel 868 of the plunger body 860 when the actuator switch 960 is rotated.

In some embodiments, as shown in FIG17 , the actuator lever 920 may include a lever biasing member or mechanism 924, such as a coiled spring or any other similar mechanism. The lever biasing member 924 may be configured to apply a linearly increasing force when the lever biasing member 924 is depressed. In other embodiments, the lever biasing member 924 may be configured to apply an exponentially increasing force when the lever biasing member 924 is depressed, such that the force becomes significantly greater as the lever biasing member 924 is depressed. As shown in the illustrated embodiment, the lever biasing member 924 may be a coiled spring received within a recess in the actuator body 922. The lever biasing member 924 may be releasably secured to the actuator body 922 so that it can be removed for disassembly. In other embodiments, the lever biasing member 924 may be permanently secured to the actuator body 922. In yet other embodiments, because the stem biasing member 924 is positioned between two components (such as the actuator body 922 and the first housing member 1020), the stem biasing member 924 may not be connected to the actuator body 922 and may be retained within the recess.

As will be described in further detail below with respect to the operation of the embodiment of the actuation system shown in Figures 25 to 27, the stem biasing member 924 can be configured to provide a biasing force against the housing member 1020. This biasing force can be formulated so that it can exceed a threshold force to actuate the release of gas from the pressurized chamber within the device. Additionally, the stem biasing member 924 can also be configured to provide a biasing force against the actuator body 922 so that as the actuation switch moves to different positions, the actuator body 922 will translate in a direction that maintains the actuator body 922 in contact with at least a portion of the actuation switch 960 (such as the contoured surface 962).

The actuator rod 920 may include a latch moving portion 926 positioned between the first and second ends of the actuator body 922. Similar to the latch moving portions of other embodiments of the actuator rod, the latch moving portion 926 may be configured to translate a latch 928 positioned thereon so that the latch 928 may be protruded from or retracted from a hole or similar structure positioned on the plunger (e.g., the latch hole 874 positioned on the plunger body 860).

Continuing with reference to FIG. 17 , actuator switch 960 can be configured to translate actuator rod 920 through plunger body 860 toward first housing member 1020 to activate a mechanism for releasing gas contained therein. Thus, like the actuator switches in other embodiments, actuator switch 960 can be a cam having a contoured profile 962 positioned along a surface configured to contact actuator body 922. Actuator switch 960 can also include an aperture 964 configured to receive a pin (not shown in FIG. 17 ), allowing actuator switch 960 to rotate about the pin. Those skilled in the art will appreciate that actuator switch 960 can preferably be any type of switch that can be maintained in a first position, a second position, or multiple positions without requiring a user to hold the switch in place. In the illustrated embodiment, a rotating lever is used. Other switches known in the art, such as screws, latches, spring-loaded pins, or any other switches, can also be used.

18 , the actuator switch 960 is shown in a first, "initial," or "pre-actuated" position. For example, this can be a position prior to the first stage of operation. In this first position, the distance between the pin 966 and the contoured surface 962 in contact with the actuator body 922 can be a first distance such that the actuator body 922 is positioned a first distance from the end of the tubular frame 862 of the plunger body 860.

As shown in FIG. 19 , in some embodiments, the actuator switch 960 can be rotated toward a plurality of vertically oriented positions, a second or “on” position, wherein the distance between the pin 966 and the contoured surface 962 in contact with the actuator body 962 can be a second distance, such that the actuator body 922 is positioned a second distance from the end of the tubular frame 862 of the plunger body 860. This can correspond to the position of the actuator switch 960 during the first and second operating stages. In some embodiments, the second distance can be greater than the first distance. As will be described in greater detail with reference to FIGS. 25-27 , this can cause the actuator body 922 to translate toward the first housing member 1020 of the pressurization chamber. This translation can actuate the release of fluid or gas contained within the pressurization chamber.

As shown in FIG. 20 , in some embodiments, the actuator switch 960 can be further rotated toward a more horizontally oriented position, a third or "off" position, wherein the distance between the pin 966 and the contoured surface 962 in contact with the actuator body 922 can be a third distance, such that the actuator body 922 is positioned a third distance from the end of the tubular frame 862 of the plunger body 860. This can correspond to a third stage of operation and/or a final stage before injecting the injectable volume into the patient. The third distance can be less than or equal to the first distance and/or the second distance. In some embodiments, rotation toward the third position can cause the actuator body 922 to translate away from the first housing member 1020 of the pressurization chamber, thereby preventing the release of any fluid or gas from the pressurization chamber.

Referring back to FIG17 , an interlocking mechanism can be included to control and limit the movement of the actuator switch 960. As shown in the illustrated embodiment, the interlocking mechanism can include an interlocking member 970, such as a claw having an interlocking wing or clamp 972 positioned at one end and an interlocking portion 974 positioned at a second end (shown in FIG18 to FIG20 ). The interlocking clamp 972 can be configured to be received within the interlocking hole 882 or notch, recess, or other similar mechanism to maintain the interlocking clamp 972 positioned within the handle 864.

Referring again to Figures 18-20, an illustration of the operation of an embodiment of the interlock mechanism is provided. Figure 18 is an illustration of the interlock mechanism and activation switch 960 in a first, "initial," or "pre-actuated" position. As shown in the illustrated embodiment, the interlock member 970 is sized and shaped to be received within the interlock channel 884 of the handle 864. When in the first position, the interlock clip 972 can be biased inwardly by contact between the interlock clip 972 and the inner surface of the channel 884.

As shown in the illustrated embodiment, the interlock portion 974 of the interlock member 970 can be received within a notch or indentation 976 located at one end of the actuator switch 960. The shapes of the interlock portion 974 and the notch or indentation 976 can be selected so that, when in the first or "home" position, the actuator switch 960 is prevented or restricted from rotating in a clockwise direction toward a horizontally oriented position (i.e., the third or "off" position) due to interference between the interlock portion 974 and the actuator switch notch 976. Additionally, the shape of the interlock portion 974 can be selected so that, in the first position, the actuator switch 960 can rotate in a counterclockwise direction toward a more vertically oriented position (i.e., the second or "on" position). In some embodiments, such as shown in the illustrated embodiment, the actuator switch 960 can include a second contoured surface 978 configured to cause the interlock member 970 to translate toward the opposite end of the handle 864 when the actuator switch 960 is rotated from the first position to the second position. In some embodiments, movement of the interlock member 970 within the interlock channel 884 toward the opposite end of the handle 864 causes the end of the interlock clip 972 to translate toward the interlock aperture 882. Once at the interlock aperture 882, the interlock clip 972, which is initially pre-biased inward within the interlock channel 884, extends outward so that the interlock clip 972 is received within the interlock aperture 882. In some embodiments, after the interlock member 970 is received within the interlock aperture 882, the interlock member can be prevented from translating back toward the activation switch 960. This can help prevent, or at least significantly reduce, the possibility that the interlock member 970 can reengage the activation switch 960 and restrict movement of the activation switch 960.

19 is an illustration of the actuator switch 960 and the interlock mechanism in a second or "on" position. As shown, the interlocking clip 972 of the interlocking member 970 is received within the interlocking aperture 882, such that the interlocking member 970 cannot be translated back toward the actuator switch 960. Thus, the device user can rotate the actuator switch 960 in a clockwise direction toward the third or "off" position.

FIG20 is an illustration of the actuator switch 960 and the interlock mechanism in a third or "off" position. In some embodiments, the actuator switch 960 can be received within a recess 880 of the handle 864 and flush with the top surface of the handle. Furthermore, the recess 880 is sized and shaped to closely conform to the shape of the actuator switch 960, making it difficult for a device user to rotate the actuator switch 960 to one of the first two positions after the actuator switch is fully positioned in the third position.

Thus, the interlock mechanism facilitates controlling the operation of the actuator switch 960 so that the device user does not accidentally turn the actuator switch 960 to an inappropriate position or in an inappropriate order. Moreover, because it is more difficult for the device user to turn the actuator switch 960 from the third position to one of the first two positions, the possibility that the user may change the concentration of the injectable volume after the final operation stage is reduced. Thus, the interlock mechanism facilitates use as a safety mechanism for device operation. In other embodiments, other forms of interlock mechanisms may be used, including the use of other fasteners, clamps, or similar devices. It will be appreciated by those skilled in the art that other types of interlock mechanisms may also be used.

21 to 23 , diagrams illustrating the operation of an embodiment of the actuation system are shown. As shown in the illustrated embodiment, and similar to other embodiments, the latch 928 can be received within the latch aperture 874 so that the latch cannot translate toward the front or rear end of the plunger body 860. In this embodiment, when the actuator rod 920 translates in the forward or rearward direction, the latch 928 is configured to follow the profile of the latch moving portion 926 of the actuator rod 920.

FIG21 illustrates an embodiment in a first, "initial" or "pre-actuated" position. As shown, the latch 928 can be positioned so that it protrudes sufficiently outward from the plunger body 860 so that if extended rearward, the latch 928 will contact a variable stop located on the metering body 922 and prevent any further extension. In other embodiments, when in the first position, the latch 928 can be configured not to protrude outward from the body 860 to prevent extension. As shown in FIG22 , when moved to the second or "open" position, the latch 928 can protrude sufficiently outward from the plunger body 860 so that the latch 928 can contact a variable stop or similar structure located on the metering scale 820, thereby preventing any further rearward extension. As shown in Figure 23, when rotated to the third or "closed" position, the latch 928 can be retracted sufficiently into the latch hole 874 so that the latch 928 no longer contacts the variable stop or similar structure positioned on the metering dial 820, thereby allowing the plunger body 860 to extend further rearward.

Continuing with reference to Figures 21 to 23, a ratchet member 886 (such as a ratchet pawl) can be attached to the plunger body 860. The ratchet member 886 can be hinged and configured so that the ratchet member 886 can be movably deformed and provide resistance during deformation. The ratchet member 886 can correspond to a structure (such as a notch 842) positioned on the plunger body metering dial 820 so as to be appropriately positioned relative to the selected concentration. In order to allow the inward deformation of the ratchet member 886, the actuator body 924 may include a recess or notch 980. The recess 980 can be configured so as to allow the ratchet member 886 to deform inwardly only in the first position and the third position, and when in the second position, limit the inward deformation of the ratchet member 886. This can provide a method for reducing the possibility of the plunger body 860 rotating during operation of the device.

Implementation of the pressurized chamber

Referring to FIG. 24 , an embodiment of a pressurization chamber and components of an actuation system is shown. As shown, the pressurization chamber may have a two-part housing having a first housing member 1020 and a second housing member 1022 that are translatable relative to each other. As shown in the illustrated embodiment, the two members 1020, 1022 may have a generally cylindrical shape, such that some or all of the two members 1020, 1022 may be received within the channel 868 of the plunger body 860. In some embodiments, the two members 1020, 1022 may be detached from each other to allow for free translation of the two members 1020, 1022. In other embodiments, the two-part housing may be attached while still allowing the members 1020, 1022 to translate relative to each other. This attachment may serve to increase the stability of the two members 1020, 1022.

As shown in the illustrated embodiment and similar to other embodiments of the pressurized chamber, an annular groove 1024 can be positioned on the second housing member 1022. In the illustrated embodiment, the annular groove 1024 can be positioned on the end opposite the first housing member 1020, however, other possible locations can be selected. The annular groove 1024 can be sized and configured to receive the retaining wings 870 of the plunger body 860, thereby allowing the second housing member 1022 to be fastened to the plunger body 860 using a snap-fit connection. To facilitate insertion of the second housing member 1022 into the channel 868 of the plunger body 860, the inserted end can be slightly tapered. In some embodiments, the second housing member 1022 can be removably attached to the plunger body 860, thereby allowing replacement of specific parts contained therein. For example, in some embodiments, the storage member 1030 or container can be contained within the two-part housing. The two-part housing may also have a plunger end 1060 having a piston seal 1061 (such as a rubber O-ring) configured to seal against the syringe body 1120 and form a seal for defining a chamber containing the injectable volume, which chamber may serve as a mixing chamber. Other types of sealing members may be used around the plunger end to form this seal.

25A and 25B are cross-sectional views of the embodiment shown in FIG. 24 when the device is in a first, "initial," or "pre-actuated" position. As more clearly shown in FIG. 25B , in the first position, a rod biasing member 924 (such as a coil spring) can contact both the actuator body 922 and the first housing member 1020; however, the actuator body 922 cannot directly contact the first housing member 1020. In the first position, the rod biasing member 924 can apply a force in a forward direction to the first housing member 1020 and a force in a rearward direction to the actuator body 922 so that the actuator body 922 remains in contact with the actuator switch 960. In this position, as the first housing member 1020 attempts to translate toward the second housing member 1022, the forward force exerted on the first housing member 1020 can cause the first housing member 1020 to apply a force to the storage member 1030 housed therein. Preferably, in the first position, due to the mechanism contained within the storage member 1030 (as discussed in further detail in Figures 28 and 29), the force applied by the first housing member 1020 to the storage member 1030 is insufficient to translate the storage member 1030 toward the second housing member 1022. Thus, when in the first position, any gas or fluid contained within the storage member 1030 remains contained within the storage member 1030.

FIG26A and FIG26B are cross-sectional views of the embodiment shown in FIG24 when the device is in the second, or "open," position. As more clearly shown in FIG26B , in the second position, both the actuator body 922 and the rod biasing member 924 can be in direct contact with the first housing member 1020. Due to this direct contact, a greater force can be applied to the first housing member 1020, causing the first housing member 1020 to translate in a forward direction, thereby causing the storage member 1030 to translate in a forward direction. This forward translation of the storage member 1030 can then actuate the release of gas from the storage member 1030. In other embodiments, the actuator body 922 need not be in direct contact with the first housing member 1020. In such embodiments, the increased force applied by the rod biasing member 924 due to depression of the rod biasing member 924 is sufficient to cause the first housing member 1020 to translate in a forward direction, thereby actuating the release of gas from the storage member 1030.

Figures 27A and 27B are cross-sectional views of the second embodiment shown in Figure 24 when the device is in a third, or "closed," position. As shown in Figure 27B, in the third position, the actuator body 922 may not be in contact with the first housing member 1020. Furthermore, in some embodiments, due to the reduced distance between the pin 966 and the contoured surface 962, the force applied by the rod biasing member 924 in a rearward direction to the actuator body 922 may cause the actuator body 922 to translate toward the contoured surface 962, such that the actuator body 922 remains in contact with the activation switch 960. The expansion of the rod biasing member 924 results in a reduction in the force applied by the rod biasing member 924 on the first housing member 1020. Due to this reduced force, and due to other mechanisms positioned within the reservoir member 1030 or within the container, the reservoir member 1030 may be restored to a closed state, thereby preventing any additional gas from being released into the chamber containing the injectable volume, which may also serve as a mixing chamber.

FIG28 is a cross-sectional view of an embodiment of a pressurized chamber. The first housing member 1020 and the second housing member 1020, 1022 contain a storage member 1030 or a container, such as a micro-cylinder (containing a fluid such as a gas). In some embodiments, the second member 1022 has a conical or frusto-conical surface at the end opposite the first member 1020 that forms a plunger end 1060. In some embodiments, the second member 1022 and the plunger end 1060 form an integral unit. In other embodiments, the second member 1022 and the plunger end 1060 are separate units that can be attached using various fastening devices and methods (such as, but not limited to, fasteners such as screws and pins, retaining clamps, adhesives, and welds). The plunger end 1060 may have an annular groove. The annular groove is configured to receive a piston seal 1061 (such as an O-ring), thereby forming a chamber for the injectable volume, which can also serve as a mixing chamber.

The first housing member 1020 may include a recess 1026, or indentation, configured to contact and receive the first end of the storage member 1030. The shape of the recess 1026 should preferably correspond to the shape of the first end of the storage member 1030. In other embodiments, the first housing member 1020 may not include the recess 1026. The second housing member 1022 may include an interior space 1028 sized and configured to receive the second end of the storage member 1030. In some embodiments, the interior space 1028 may include a housing seal 1029 that contacts the second end of the storage member 1030. In some embodiments, the housing seal 1029 forms a sufficient seal to prevent any, or minimal, gas from leaking rearward through the interior space 1028. In some embodiments, the interior space 1028 may also provide a substantially snug fit around the storage member 1030, ensuring that the storage member 1030 typically translates only in the forward and rearward directions. This helps reduce the likelihood of damage to the seal between the second end of the storage member 1030 and the housing seal 1029.

Continuing with reference to FIG. 28 , storage member 1030 (such as the illustrated container can or micro-cylinder) may include a body 1040 and a head 1042. As shown in the illustrated embodiment, body 1040 may have a generally cylindrical shape with a hemispherical first end. Body 1040 and head 1042 may together form an interior volume 1041 to accommodate a fluid, such as a gas, in gaseous or liquid form, or a mixture of gaseous and liquid forms, the fluid being at a first pressure and concentration different from atmospheric gases. For example, the gas may include, but is not limited to, dilatant gases, ophthalmic gases (such _{as SF₆} , _C₃F₈ , _C₂F₆ , _etc. ), propellant gases (such as _CO₂ ), refrigerant gases (such as _N₂O ), and various other types of gases. The dimensions of interior volume 1041 may be selected so that a unit dose or disposable dose can be contained within the volume. Other shapes may be selected for body 1040.

The head 1042 may have a generally tubular shape with an outer diameter that matches the inner diameter of the body 1040. The head 1042 may have an internal passageway and a flange 1044. As shown in the illustrated embodiment, the diameter of the opening at the first end of the head 1042 may match the diameter of the passageway, and the diameter of the opening 1046 at the second end of the head 1042 may be smaller than the diameter of the passageway. In some embodiments, the body 1040 and the head 1042 may be separate components that are attached later. Advantageously, this may allow the internal components of the head 1042 to be assembled prior to assembly. Once all components are assembled within the head 1042, the head 1042 may be received within the body 1040 and secured using devices and mechanisms (such as adhesives or welding). In some embodiments, such as shown in FIG. 28 , the flange 1044 may abut against the body 1040 and be bonded or welded along this surface. In other embodiments, the body 1040 and the head 1042 may form a single, integral unit.

The head 1042 may include a storage member pressure regulation system, which may form part of the first pressure regulation system and may have the form of an internal valve mechanism within the passageway. The internal valve mechanism may include a retaining ring 1048, a valve seat 1050, an internal biasing member or mechanism 1052 (such as a spring), a valve piston 1054, and a piston seal 1056. The retaining ring 1048 may be positioned within an annular groove 1058, which may be located on the head 1042. The retaining ring 1048 may be made of an elastic material so that the retaining ring can be deformed before being fitted into the groove 1058. The valve seat 1050 may be positioned between the retaining ring 1048 and the second end of the head 1042. In some embodiments, the valve seat 1050 may be a ring having an outer diameter approximately equal to the inner diameter of the head 1042.

The valve piston 1054 can have a generally cylindrical shape and be positioned between the valve seat 1050 and the second end of the head 1042. The outer diameter of the valve piston 1054 can be selected to be approximately equal to the inner diameter of the head 1042. As shown in the illustrated embodiment, the valve piston can include an annular groove configured to receive a plunger seal 1056, fluid paths 1055 or channels positioned along the circumference of the plunger, and a protrusion 1057. The fluid paths 1055 can be configured to allow fluid to pass between the valve piston 1054 and the head 1042. In the illustrated embodiment, a total of four fluid paths are included; however, a fewer or greater number of paths may be used. In some embodiments, the protrusion 1057 can be a cylindrical member having a smaller diameter corresponding to the diameter of the opening 1046. The protrusion 1057 can be configured to fit within the opening 1046. In some embodiments, the protrusion 1057 can be flush with the end surface of the head 1042. In other embodiments, the protrusion 1057 may be recessed within the opening or extend beyond the end surface. The biasing mechanism 1052 may be positioned between the valve seat 1050 and the plunger 1054 to apply a force to the valve piston 1054 in a forward direction, thereby forming a seal between the piston seal 1056 and the head 1042. In other embodiments, other types of valve designs may be used, such as ball valves, poppet valves, or any other valves described herein or known in the art.

In some embodiments, the internal biasing mechanism 1052 can be configured such that when the actuation switch is in the first or "pre-actuated" position, the internal valve mechanism will not open due to any force applied thereto (such as a force applied to the storage member 1030 via the first housing member 1020 due to the lever biasing mechanism 924). In some embodiments, the internal biasing mechanism 1052 can be configured such that when the actuation switch is in the second or "open" position, the internal valve mechanism will open due to a force applied thereto. In some embodiments, the internal biasing mechanism 1052 can be configured such that when the actuation switch is in the third or "closed" position, the internal valve mechanism will not open due to any force applied thereto (such as a force applied to the storage member 1030 via the first housing member 1020 due to the lever biasing mechanism 924).

In some embodiments, the storage member 1030 may include other structures, such as a filter incorporated in a portion of the storage member 1030, such as the head 1042. The storage member 1030 may include a membrane or other sealing structure positioned on the head 1042 and the opening 1046 to provide an additional seal that is conducive to extending the shelf life of the storage member 1030. The membrane or sealing structure may be pierced by a protruding member, such as a pin 1059 or any other similar release mechanism. In some embodiments, the release mechanism may be a porous material, for example, a known "frit". The storage member 1030 may also include an additional valve member serving as a release valve to reduce the possibility of rupture when the pressure contained in the storage member 1030 exceeds a specific operating limit. The storage member 1030 may also be configured to rupture in a controlled manner to reduce the possibility of catastrophic failure.

In some embodiments, storage member 1030 and internal member (such as internal valve) are made of small and light material. Such material can also be flexible. In some embodiments, the material and size of storage member 1030 can be selected so that storage member 1030 prevents gas from diffusing through the wall of storage member 1030. This can provide the advantage of extending the storage life of storage member 1030 when gas is accommodated in the storage member. In some embodiments, the range of the length of storage member 1030 from the rearmost end of body 1040 to the frontmost end of head 1042 can be about 15mm to about 65mm, about 20mm to about 45mm and about 25mm to about 35mm, such as, 29mm. In some embodiments, the outer diameter range of body 1040 can be about 4mm to about 25mm, about 6mm to about 20mm and about 8mm to about 15mm, such as, 9.5mm. In some embodiments, the outer diameter of the head 1042 excluding the flange portion can range from about 2 mm to about 20 mm, about 4 mm to about 15 mm, and about 6 mm to about 10 mm, such as 7.5 mm.

Continuing with reference to FIG28 , the second housing member 1022 can include a release mechanism 1059 positioned within the passage 1062. The release mechanism 1059 can be located approximately centrally above the protrusion 1057 of the valve piston 1054 and have a diameter that matches the diameter of the opening 1046. As shown in FIG29 , during operation, when the storage member 1030 translates in a forward direction toward the release mechanism 1059, the release mechanism 1059 remains stationary, thereby causing the release mechanism 1059 to disengage the valve piston 1056 from the head 1042, thereby allowing fluid to flow from the storage member 1030, through the path 1055 and the release mechanism 1059, and through the passage 1062, where it ultimately flows into a chamber for the injectable chamber (such as a mixing chamber). In some embodiments, the release mechanism 1059 can be made of a porous material so that the release mechanism 1059 itself acts as a preliminary filtering mechanism for fluid flowing through the passage 1062. In some embodiments, a filter may be added between the release mechanism 1059 and the end of the channel 1062 or any other location to filter the material.

With reference to Figure 30, an embodiment of a chamber (such as a mixing chamber) for injectable volumes is shown, which may include a syringe body 1120, a syringe pressure regulation system that may form part of a second pressure regulation system, and the components of the systems described above. The syringe body 1120 may have a cylindrical body and a nose 1122 located at the front end. In some embodiments, a threaded nozzle 1124 that may include multiple components of the pressure regulation system is movably attached to the nose 1122 of the syringe body 1120. Advantageously, this may facilitate assembly of the device by allowing the pressure regulation system to be assembled within the smaller nozzle 1124 before being combined with the syringe body 1120. A variety of fastening devices and means such as screws, adhesives, snap fits, welding, etc. may be used to attach the nozzle 1124 to the nose 1122. The chamber for injectable volumes may be defined by the inner wall of the syringe body 1120 and the piston seal 1061. Moreover, as with other embodiments of the syringe, the syringe body 1120 may further include an indicator along its outer surface corresponding to the selected concentration and a flange located at the rear end of the body 1120 configured to attach to a metering dial.

30 , an embodiment of a syringe pressure regulating system is shown that includes a valve body 1220, a valve tip 1222, a valve piston 1224, a piston seal 1226, a piston biasing member or mechanism 1228, a valve biasing member or mechanism 1230, and a valve tip seal 1232. Similar to other embodiments of the pressure regulating system, the valve body 1220 and the valve tip 1222 are slidably translatable within the threaded nozzle 1124.

In a first position, for example, as shown in FIG30 , the valve end 1222 can rest against the lip 1234 of the threaded nozzle 1124 due to the force exerted in a forward direction by the valve biasing member 1230 on the valve body 1220 and the valve end 1222. In the first position, the valve piston 1224 and the valve seal 1226 can form a seal and restrict or prevent fluid flow through the valve body 1220. However, when the pressure within the chamber for the injectable volume increases above a threshold to overcome the biasing force exerted by the piston biasing member 1228, the valve piston 1224 can translate in a forward direction against the force exerted by the piston biasing member 1228, and fluid can flow through the valve body 1220 and the valve end 1222 into the atmosphere. Once the pressure decreases back to the threshold, the equalization of the forces allows the valve piston 1224 and the valve seal 1226 to once again seal with the valve body 1220.

In the second position, the valve body 1220 and valve tip 1222 can translate rearward against the valve biasing member 1230. This can be achieved, for example, by applying a force to the valve tip 1222 in the rearward direction. In the second position, contact between the valve piston 1234 and the internal protruding member 1126 of the syringe body 1120 can cause the valve piston 1224 to move rearward relative to the valve body 1220 and valve tip 1222, such that the valve piston 1224 is no longer in sealing contact with the valve body 1220. In some embodiments, this can allow fluid to flow into and out of the chamber for the injectable volume. In some embodiments, the pressure regulation system can be pressurized into the second position when the inline filter is screwed onto the threaded nozzle 1124. For example, as shown in FIG. 14 , attachment 760 can be used. Other types of attachments, such as stopcocks, valves, tubing, etc., can also be attached to the threaded nozzle 1124.

External gas filling

In some embodiments, the pressurized chamber may be located outside the device. In this embodiment, the pressurized chamber may be a tank or other container containing gas in liquid or gaseous (or mixed) form. In some embodiments, the tank may be attached to a threaded nozzle via a pipe or other mechanism. The connection between the threaded nozzle and the pipe can cause a pressure regulation system located on the device to be forced to open, allowing gas from the tank to enter the chamber. In some embodiments, the introduction of gas from the tank can be performed during the first operating phase. Therefore, the gas from the tank can be used to fill the device until the device reaches the first configured volume. In some embodiments, the tank may have a regulator to allow the device to be filled with gas at a regulated pressure. The connection from the threaded nozzle can then be removed, allowing the valve to function normally. In some embodiments, because the gas may be at a higher pressure than atmospheric air and may exceed the threshold for the pressure regulation system, the gas can be vented or discharged from the system until the set pressure is achieved within the device. Once the set pressure is achieved within the device, the remaining operating phases can be completed in the same manner as in the above-described embodiments.

The foregoing describes an apparatus and method for mixing and/or injecting gases having specific characteristics, aspects, and advantages according to the present invention. Various changes and modifications may be made to the above-described gas mixing apparatus and method without departing from the spirit and scope of the present invention. Thus, for example, it will be appreciated by those skilled in the art that a method of achieving or optimizing one or various advantages taught in the present invention may embody or accomplish the present invention without necessarily achieving other objectives or advantages taught or suggested in the present invention. Furthermore, while various variations of the present invention have been shown and described in detail, other variations and methods used will be apparent to those skilled in the art based on the present disclosure within the scope of the present invention. It is conceivable that various combinations or variations may be made to the specific features and aspects of the embodiments and still fall within the scope of the present invention. Therefore, it will be understood that various characteristics and aspects of the disclosed embodiments may be combined or substituted for one another in order to form various modes of the disclosed gas mixing apparatus.

Claims (43)

1. A handheld gas injector device, comprising: A syringe body having an outlet; A plunger, which is slidably disposed within the syringe body and together with the syringe body defines a first chamber within the syringe body; A second chamber, disposed within the plunger, includes a seal and an internal volume containing at least a first gas with a concentration different from that of the atmosphere and a pressure greater than that of the surrounding atmosphere. A metering device at least partially located in the syringe body, the metering device being configured to control the volume of at least the first chamber when a first gas is introduced into the first chamber, wherein the metering device includes a plurality of protrusions disposed inwardly from an inner wall of the first chamber and a selector ring having protrusions, the protrusions of the selector ring being movable between positions aligned with the plurality of protrusions disposed inwardly from the inner wall of the first chamber, wherein each of the plurality of protrusions includes a surface configured to contact the protrusion of the selector ring to restrict movement of the plunger to one of a plurality of different positions, each different position corresponding to a different volume of the first chamber; and; A device configured to direct the first gas into the first chamber of the syringe body to move the plunger and expand the first chamber. 2. The handheld gas injector device of claim 1, wherein the metering device is configured to limit the expansion of the first chamber to a first volume during the filling of the first chamber with the first gas. 3. The handheld gas injector device of claim 2, wherein the metering device includes at least one locking mechanism configured to define a plurality of different limits on the expansion of the first chamber. 4. The handheld gas injector device of claim 3, wherein the first locking mechanism is unlockable to allow further expansion of the first chamber. 5. The handheld gas injector device according to claim 3, wherein the first locking mechanism comprises one or more stops and a latch. 6. The handheld gas injector device of claim 3, wherein the plunger is configured to rotate relative to the metering device for selecting from a plurality of different expansion levels of the first chamber. 7. The handheld gas injector device according to claim 1, wherein the first chamber is a mixing chamber configured to mix gas from the second chamber with gas outside the second chamber. 8. The handheld gas injector device according to claim 1 further includes an actuation system. 9. The handheld gas injector device according to claim 8, wherein the actuation system comprises an actuation switch and an actuation rod. 10. The handheld gas injector device according to claim 1, wherein the handheld gas injector device further includes a pressure regulating system. 11. The handheld gas injector device of claim 10, wherein the pressure regulating system comprises a first pressure regulating system configured to regulate the gas in the second chamber and a second pressure regulating system configured to regulate the gas in the first chamber. 12. The handheld gas injector device according to claim 11, wherein when the pressure inside the first chamber exceeds a threshold, the second pressure regulating system releases gas outside the first chamber. 13. The handheld gas injector device according to claim 11, wherein when the pressure in the second chamber exceeds a threshold, the first pressure regulating system releases gas outside the second chamber. 14. The handheld gas injector device of claim 11, wherein the handheld gas injector device further comprises an actuation system operatively coupled to the second chamber. 15. The handheld gas injector device of claim 14, wherein the actuation system is configured to release gas from the second chamber. 16. The handheld gas injector device of claim 14, wherein the actuation system is operatively coupled to the first pressure regulating system. 17. The handheld gas injector device according to claim 10, wherein the pressure regulating system includes at least one check valve. 18. The handheld gas injector device according to claim 1, wherein the second chamber further includes a release mechanism, the release mechanism including a puncture device. 19. The handheld gas injector device of claim 18, wherein the puncture device comprises at least one of a needle and a guide tip. 20. The handheld gas injector device of claim 1, further comprising a second chamber, the second chamber including an internal volume containing at least the first gas having a concentration different from that of the atmosphere and a pressure greater than that of the surrounding atmosphere. 21. The handheld gas injector device according to claim 20, wherein the second chamber is located outside the handheld gas injector device. 22. The handheld gas injector device of claim 20, wherein the second chamber is a storage member comprising an opening at a first end and an internal valve mechanism positioned adjacent to the first end, the internal valve mechanism being configured to seal the opening. 23. The handheld gas injector device of claim 22, wherein the internal valve mechanism includes a plunger, a seal, and a biasing member, the internal valve mechanism being configured to seal the opening at least before actuation of the system. 24. The handheld gas injector device according to claim 23, wherein when the actuation system is in the "on" position, the internal valve mechanism does not seal the opening during the operation phase. 25. The handheld gas injector device of claim 22, wherein the storage member includes a membrane located on the first end to seal the opening. 26. The handheld gas injector device of claim 22, wherein the storage member includes a release valve configured to release the first gas when the pressure within the storage member exceeds a predetermined value. 27. The handheld gas injector device according to claim 1 further includes a release mechanism, wherein the release mechanism includes a pin. 28. The handheld gas injector device of claim 27, wherein the release mechanism comprises a porous material configured to at least partially filter the first gas. 29. The handheld gas injector device of claim 1, further comprising an actuation system configured to initiate and control the operation of the handheld gas injector device. 30. The handheld gas injector device of claim 29, wherein the actuation system includes an actuation switch and an interlocking mechanism, the interlocking mechanism being configured to restrict movement of the actuation switch to prevent the actuation switch from moving in an inappropriate sequence. 31. The handheld gas injector device of claim 30, wherein when the actuation switch is in the initial position, the interlocking mechanism prevents movement toward the closed position. 32. The handheld gas injector device according to claim 30, wherein when the actuation switch moves from the initial position to the open position, the interlocking mechanism does not impede movement toward the closed position. 33. The handheld gas injector device of claim 30, wherein the actuation switch is received in a recess of the plunger handle when in the closed position. 34. The handheld gas injector device according to claim 33, wherein the actuation switch is flush with or integrally positioned in the recess of the handle. 35. The handheld gas injector device of claim 8, wherein the actuation system includes an actuation switch, an actuator body, and a biasing member configured to apply a force to at least one of the actuator body and the housing member. 36. The handheld gas injector device of claim 22, further comprising a housing configured to receive the storage member. 37. The handheld gas injector device of claim 36, wherein the housing comprises two portions, wherein the two portions are configured to translate toward each other to actuate the release of gas from the storage member. 38. A handheld gas injector assembly, comprising: A syringe body that at least partially defines a first chamber; Device for adjusting the volume of the first chamber; A means for releasing one or more gases into a first chamber to move the means for adjusting the volume of the first chamber and to expand the first chamber; An apparatus for containing one or more gases with a concentration different from that of the atmosphere and a pressure greater than that of the surrounding atmosphere; and A means for selectively limiting the expansion of the first chamber, wherein, when one or more gases are introduced into the first chamber to produce a desired concentration within an injectable volume, the means selectively limits the expansion of the first chamber, at least during the operation phase of the handheld gas injector assembly, wherein the means for selectively limiting the expansion of the first chamber includes a latch movable between multiple positions, wherein the latch is respectively aligned with a plurality of different protrusions, wherein the plurality of different protrusions are disposed inwardly from the inner wall of the first chamber, wherein each of the plurality of different protrusions includes a surface configured to define a contact point with the latch to limit the movement of the means for adjusting the volume of the first chamber to one of a plurality of different discrete positions, each discrete position corresponding to a different volume of the first chamber. 39. The handheld gas injector assembly of claim 38, wherein the first chamber is a mixing chamber configured to mix the one or more gases with another gas. 40. The handheld gas injector assembly of claim 38, wherein the handheld gas injector assembly further includes means for adjusting the pressure in the first chamber. 41. The handheld gas injector assembly of claim 40, wherein the handheld gas injector assembly further includes means for adjusting the pressure within the device containing the one or more gases. 42. The handheld gas injector assembly of claim 38, wherein the means for altering the expansion is configured to limit expansion to a first volume during at least a first operational phase. 43. The handheld gas injector assembly of claim 38, wherein the means for altering the expansion is configured to limit expansion to the injectable volume.