WO2014089358A1

WO2014089358A1 - Pressure and flow regulator for pressurized containers

Info

Publication number: WO2014089358A1
Application number: PCT/US2013/073417
Authority: WO
Inventors: James J. Leary
Original assignee: PADA MEDICAL PRODUCTS LLC
Current assignee: PADA MEDICAL PRODUCTS LLC
Priority date: 2012-12-05
Filing date: 2013-12-05
Publication date: 2014-06-12
Anticipated expiration: 2015-06-05

Abstract

A pressure regulator is configured for attachment to a gas-pressurized container, such as an aerosol can, which has a pressure valve internal to the container. The pressure regulator includes a pressure-responsive valve actuation mechanism external to the container and configured to actuate the pressure valve to maintain a substantially constant gas pressure in a pressure chamber downstream of the pressure valve. A pressure adjustment screw allows adjustment of a set pressure of the pressure regulator. Optionally, a flow restrictor having a known resistance to fluid flow may be connected with a gas outlet of the pressure regulator to provide a controllable gas flow rate.

Description

PRESSURE AND FLOW REGULATOR FOR PRESSURIZED CONTAINERS

FIELD OF THE INVENTION

The present invention relates generally to gas pressure regulators and flow regulators and more particularly to a gas pressure regulator and flow regulator that is especially adapted for use with gas-pressurized containers, such as aerosol cans.

BACKGROUND OF THE INVENTION

There are a great many applications that could benefit from a lightweight, portable, low cost source of pressurized gas that can deliver the gas at a controlled pressure and/or flow rate.

Potential applications include controlled delivery of medical gases, medical nebulizers and atomizers, powering portable hand tools or surgical tools, powering small pneumatic control circuits, for example those used in miniature robots or radio controlled model airplanes.

Miniature gas pressure regulators are commercially available. For example, Beswick

Engineering Co. Inc. of Greenland, New Hampshire manufactures a variety of miniature and subminiature gas pressure regulators in single-stage, double-stage and triple-stage models. These gas pressure regulators can be made very small and lightweight, but they are generally quite expensive and so are not suitable for every application. One factor that contributes to the expense of manufacturing is that each pressure regulator requires a precision-made, high-pressure valve for turning on and off the flow of gas from a high pressure source in response to a pressure- responsive valve control mechanism such as a piston or diaphragm that actuates the valve. These commercially-available miniature gas pressure regulators are also not adapted for direct application to an aerosol can containing pressurized gas.

Aerosol cans have certain advantages as containers for pressurized gases. They are low-cost, light-weight and readily available in a variety of different sizes. Of particular advantage in the present invention is the fact that aerosol cans already come with an aerosol valve configured for dispensing material from the aerosol can. An aerosol dispensing valve is typically not configured for precision operation, but when coupled with a pressure-responsive valve actuation

mechanism, the aerosol valve can be used as a pressure valve within a gas pressure regulator. This significantly reduces the weight, complexity and cost of the gas pressure regulator.

When coupled with a calibrated flow restrictor having a known fluid flow resistance, a gas pressure regulator can be operated as a gas flow regulator for delivering gas at a known flow rate. Optionally, the flow restrictor can be adjustable for changing the flow rate of the gas delivered.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a gas pressure regulator that is especially adapted for use with gas-pressurized containers, such as aerosol cans. The gas pressure regulator utilizes an aerosol dispensing valve located inside of the aerosol can as an integral part of the gas pressure regulator. The aerosol dispensing valve is coupled with a pressure -responsive valve actuation mechanism to create a fully operational gas pressure regulator. The aerosol dispensing valve is located inside the pressurized enclosure of the aerosol can, whereas the pressure- responsive valve actuation mechanism of the gas pressure regulator is located external to the pressurized enclosure of the aerosol can.

In a second aspect, the present invention provides a gas flow regulator for delivering gas at a known flow rate by coupling the gas pressure regulator with a calibrated flow restrictor having a known fluid flow resistance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section showing the gas pressure regulator of the present invention assembled to an aerosol can with an aerosol valve internal to the pressurized aerosol can.

FIG. 2 is an enlarged cross section showing the gas pressure regulator, the aerosol valve and the aerosol can disassembled.

FIG. 3 is an enlarged cross section showing the gas pressure regulator, the aerosol valve and the aerosol can assembled together.

DETAILED DESCRIPTION

FIG. 1 is a cross section showing the gas pressure regulator 10 of the present invention assembled to an aerosol can 14 with an aerosol valve 12 internal to the pressurized aerosol can 14. The aerosol can 14 may be made from aluminum, steel, tin-plated steel, stainless steel, a fiber-reinforced composite or other suitable material and may have a protective coating, such as epoxy, epoxy phenolic or vinyl, on the interior and/or an identifying label or other indicia on the exterior. In one preferred embodiment, the aerosol can 14 is a deep-drawn seamless aluminum can. Suitable aerosol cans of this type are commercially available with working pressures of approximately 18-25 bars. Higher pressures may be achieved with custom-made aerosol cans. The volume of the aerosol can 14 will typically range from 25 to 1000 ml, although larger or smaller sizes may be preferred for certain applications.

The aerosol can 14 will preferably be filled with a gas or mixture of gases that does not liquefy at the pressures and temperatures used. The actual gas or mixture of gases used will depend on the application of the regulator. Examples of suitable gases include, but are not limited to, air, oxygen, nitrogen, argon, carbon dioxide and mixtures of these gases. Since these gases do not liquefy at the pressures and temperatures typically used in aerosol cans, without a pressure regulator, the gas will initially be dispensed at high pressure and the pressure will gradually decay as the aerosol can becomes empty. However, the gas pressure regulator 10 allows the gas to be dispensed at a relatively constant pressure. When the gas pressure regulator 10 is coupled to a calibrated flow restrictor having a known fluid flow resistance, the gas pressure regulator 10 can be operated as a gas flow regulator for delivering gas at a known flow rate.

Alternatively, the aerosol can 14 may be filled with an aerosol propellant that will liquefy at the pressures and temperatures used. The gas pressure regulator 10 can be used to dispense the propellant at a constant pressure that is below the vapor pressure of the propellant in the aerosol can 14.

Optionally, the compressed gas or the aerosol propellant in the aerosol can 14 may be used to dispense other materials in gaseous, liquid or solid form. For example, gas, liquid, foam or powdered medications, cosmetics, foods, cleaners, lubricants, paints and other materials can be dispensed from the aerosol can 14 or from another container pressurized using the gas pressure regulator 10.

FIG. 2 is an enlarged cross section showing the gas pressure regulator 10, the aerosol valve 12 and the aerosol can 14 disassembled. FIG. 3 is an enlarged cross section showing the gas pressure regulator 10, the aerosol valve 12 and the aerosol can 14 assembled together.

In the embodiment shown, the aerosol valve 12 is a threaded female valve that is attached to the aerosol can 14 via a mounting cup 40. The mounting cup 40 is preferably made from steel, tin- plated steel or stainless steel. The mounting cup 40 may be made with protective and/or decorative coatings or surface treatments on the inner and/or outer surfaces. The mounting cup 40 has an external thread 48. Typically, the external thread 48 is a right-handed 7/16-28 UNEF, 1/2-20 UNF or 1/2-16 ACME thread, however different sizes and configurations of threads may be used, including left-handed threads. Threaded female valves for aerosol cans of this type are commercially available from LINDAL North America, Inc., Columbus, IN, and from Newman- Green, Inc., Addison, IL. The present invention can also be adapted to utilize other types of aerosol valves, including nonthreaded female valves, male valves, tilt valves, low-flow valves or metering valves.

The aerosol valve 12 includes a valve seat 52 that moves reciprocally within a valve housing 50. The aerosol valve 12 and the valve seat 52 will typically be injection molded of polyacetal or another suitable polymer material. The aerosol valve 12 has a closed position with the valve seat 52 sealed against an annulus-shaped inner gasket 46 (upward in the drawings) and an open position with the valve seat 52 moved away from the inner gasket 46 (downward in the drawings). The annulus-shaped inner gasket 46 also provides a seal between the end of the valve housing 50 and the mounting cup 40. A valve spring 54 within the valve housing 50 urges the valve seat 52 upward into the closed position where it is in sealing engagement with the inner gasket 46. The valve spring 54 is preferably made of steel, stainless steel, brass, nickel-titanium or other suitable spring material. The inner gasket 46 is typically made from neoprene, buna, chlorobutyl or butyl rubber. The aerosol valve 12 is held within the mounting cup 40 by a valve crimp 56. The outer edge of the mounting cup 40 has an outer lip 42 with an annulus-shaped outer gasket 44 that will form a seal with the rim 76 of the aerosol can 14, as shown in FIG. 3. A can crimp 58 secures the mounting cup 40 and the aerosol valve 12 to the rim 76 of the aerosol can 14. The outer gasket 44 will typically be made from buna or butyl rubber.

The gas pressure regulator 10 has a regulator housing 16 that may be made of metal, such as aluminum, brass, steel or stainless steel, a polymer or a composite material, such as a fiber- reinforced polymer composite. The regulator housing 16 and other parts of the gas pressure regulator 10 may be produced by a number of different manufacturing processes, including machining, investment casting or injection molding. The regulator housing 16 has an internal thread 34 that provides a secure attachment to the external thread 48 on the aerosol valve 12. An O-ring 38 or similar seal fits within an O-ring gland 36 at the end of the internal thread 34 and provides a pressure seal between the regulator housing 16 and the aerosol valve 12 within the mounting cup 40, as shown in FIG. 3. Preferably, the exterior of the regulator housing 16 is shaped so that it can be gripped by hand and/or with tools to tighten the gas pressure regulator 10 onto the aerosol valve 12 and the aerosol can 14. For example, the exterior of the regulator housing 16 may be configured with two or more flat sides for engaging with a wrench and/or with a handle or a lever that can be gripped by hand. The gas pressure regulator 10 includes a pressure -responsive valve control mechanism for operating the aerosol valve 12 inside of the aerosol can 14. In the embodiment shown, the pressure -responsive valve control mechanism includes a piston 20 that moves reciprocally within an internal cylinder 18 inside of the regulator housing 16. Preferably, a retainer mechanism 74 prevents the piston 20 from coming all the way out of the regulator housing 16. The retainer mechanism 74 can be configured as a C-clip that clips into a groove at the lower end of the internal cylinder 18 or a washer that is held captive by the O-ring 38 or, alternatively, an annular sealing member can perform the function of the O-ring 38 and the retainer mechanism 74. A valve actuator rod 26 extends downward from the piston 20. A sliding piston seal 24, for example an O-ring, X-seal or multiseal that fits within a piston seal gland 22 in the piston 20, forms a sliding seal between the piston 20 and the internal cylinder 18. A regulator spring 30 urges the piston 20 downward. The regulator spring 30 is preferably made of steel, stainless steel, brass, nickel-titanium or other suitable spring material. The regulator spring 30 may be configured as a helical spring, a conical spring, a wave spring or one or more stacked conical spring washers (a.k.a. Belleville washers). The piston 20 and the valve actuator rod 26 may be made of metal, such as aluminum, brass, steel or stainless steel, a polymer or a composite material, such as a fiber-reinforced polymer composite. The piston 20 and the valve actuator rod 26 may be formed integrally or they may be formed separately and assembled together.

Optionally, the gas pressure regulator 10 may include a pressure adjustment mechanism. In the embodiment shown, the pressure adjustment mechanism includes a pressure adjustment screw 70 that screws into a threaded hole 68 at the top of the regulator housing 16 and contacts a regulator spring flange 32 that fits over the end of the regulator spring 30. The pressure adjustment screw 70 can be used to adjust a preload force on the regulator spring 30, thereby adjusting the set pressure of the gas pressure regulator 10. Optionally, a locking nut or a friction lock may be provided to lock the pressure adjustment screw 70 after the pressure has been adjusted.

Alternatively, the gas pressure regulator 10 may be factory calibrated to operate at a single preset pressure.

In alternative embodiments, the pressure -responsive valve control mechanism in the gas pressure regulator 10 may utilize a diaphragm, a rolling diaphragm (e.g. a Bellofram) or a bellows in place of the reciprocating piston 20.

A pressure chamber 66 within the regulator housing 16 is bounded at its upper end by the lower surface of the piston 20. A gas outlet is in fluid communication with the pressure chamber 66. In the embodiment shown, the gas outlet is in the form of an outlet tube 60 with a tube lumen 62 that is in fluid communication with the pressure chamber 66. Optionally, the outlet tube 60 may be configured with a tubing barb 64 for easy attachment of a flexible plastic tube or the like. The outlet tube 60 may be formed integrally with the regulator housing 16, or the outlet tube 60 and the regulator housing 16 may be formed separately and assembled together. Other types of fittings, such as a threaded fitting, crimp connector, quick-disconnect fitting or Luer fitting, may also be used.

A vent hole 28 through the regulator housing 16 vents the upper portion of the internal cylinder 18 above the piston 20 to the atmosphere.

Optionally, the gas pressure regulator 10 may be constructed with or connected to a calibrated flow restrictor so that it can be operated as a gas flow regulator for delivering gas at a known flow rate. For example, the outlet tube 60 may be configured to provide a calibrated flow restrictor with a known fluid flow resistance based on the length and diameter of a flow restriction within the lumen 62 of the outlet tube 60.

Optionally, the gas pressure regulator 10 may be constructed with a pressure tap 82 that is in fluid communication with the pressure chamber 66 for connecting a pressure gauge or pressure sensor 80, as shown in FIG. 1. Alternatively, a pressure gauge or pressure sensor may be connected to the outlet tube 60 or elsewhere downstream of the gas pressure regulator 10.

The gas pressure regulator 10, the aerosol valve 12 and the aerosol can 14 are assembled together prior to use, as shown in FIGS. 1 and 3. When the pressure in the pressure chamber 66 is below the set pressure, the regulator spring 30 urges the piston 20 downward and the valve actuator rod 26 pushes downward on the valve seat 52 to open the aerosol valve 12, releasing gas from the aerosol can 14 into the pressure chamber 66. When the pressure in the pressure chamber 66 reaches the set pressure, the gas pressure acting on the surface area of the piston 20 urges the piston 20 and the valve actuator rod 26 upward against the force of the regulator spring 30 and the valve spring 54 urges the valve seat 52 upward to close the aerosol valve 12. This process repeats itself, opening and closing the aerosol valve 12 to maintain a relatively constant pressure in the pressure chamber 66.

The configuration of the gas pressure regulator of the present invention has particular advantages over prior art gas pressure regulators. By utilizing the aerosol valve within an aerosol can to turn on and off the flow of compressed gas from the can, the gas pressure regulator can be built more simply and therefore less expensively. Furthermore, when assembled and operated as described above, none of the parts of the gas pressure regulator are subjected to the full pressure of the compressed gas from the aerosol can. Consequently, the housing, piston and other components of the gas pressure regulator can be built smaller, thinner and lighter and can potentially be built from lower cost materials, such as injection molded polymers or injection moldable fiber- reinforced polymers. Because the aerosol dispensing valve is located inside the aerosol can and surrounded by the pressurized gas, the aerosol dispensing valve can also be built thin and lightweight. Because the pressure-responsive valve actuation mechanism of the gas pressure regulator is located external to the pressurized enclosure of the aerosol can, the regulator housing can easily be vented to the atmosphere, which overcomes some of the problems with prior art regulators.

While the present invention has been described herein with respect to the exemplary

embodiments and the best mode for practicing the invention, it will be apparent to one of ordinary skill in the art that many modifications, improvements and subcombinations of the various embodiments, adaptations and variations can be made to the invention without departing from the spirit and scope thereof.

Claims

I claim:

1. Apparatus comprising: a pressurized gas container of the type having a pressure valve internal to the container; and a pressure-responsive valve actuation mechanism external to the container and configured to actuate the pressure valve to maintain a substantially constant gas pressure in a pressure chamber downstream of the pressure valve.

2. The apparatus of claim 1, wherein the pressure-responsive valve actuation mechanism comprises: a piston movable within a cylinder, wherein the pressure chamber is defined by a space located between the piston and the pressure valve; a valve actuator rod extending from the piston toward the pressure valve; and a regulator spring urging the piston and valve actuator rod toward the pressure valve.

3. The apparatus of claim 2, further comprising a pressure adjustment screw for adjusting a preload force on the regulator spring, thereby adjusting a set pressure of the pressure-responsive valve actuation mechanism.

4. The apparatus of claim 1, wherein the pressure valve comprises: a valve seat that moves reciprocally within a valve housing; and a valve spring that urges the valve seat toward a closed position within the valve housing.

5. The apparatus of claim 1, further comprising a gas outlet in fluid connection with the pressure chamber.

6. The apparatus of claim 5, further comprising a flow restrictor having a known resistance to fluid flow in fluid connection with the gas outlet.

6. Apparatus comprising: an aerosol can of the type having an aerosol valve internal to the aerosol can; and a pressure regulator connected to the aerosol can, the pressure regulator including a pressure- responsive valve actuation mechanism configured to actuate the aerosol valve to maintain a substantially constant gas pressure in a pressure chamber downstream of the aerosol valve.

7. The apparatus of claim 6, wherein the aerosol valve comprises: a valve seat that moves reciprocally within a valve housing; and a valve spring that urges the valve seat toward a closed position within the valve housing.

8. The apparatus of claim 7, wherein the pressure -responsive valve actuation mechanism of the pressure regulator comprises: a piston movable within a cylinder, wherein the pressure chamber is defined by a space located between the piston and the pressure valve; a valve actuator rod extending from the piston toward the valve seat of the aerosol valve; and a regulator spring urging the piston and valve actuator rod toward the valve seat of the aerosol valve, thus urging the valve seat toward an open position within the valve housing.

9. The apparatus of claim 8, further comprising a pressure adjustment screw for adjusting a preload force on the regulator spring, thereby adjusting a set pressure of the pressure-responsive valve actuation mechanism of the pressure regulator.

10. The apparatus of claim 9, further comprising a gas outlet in fluid connection with the pressure chamber.

11. The apparatus of claim 10, further comprising a flow restrictor having a known resistance to fluid flow in fluid connection with the gas outlet.

12. Apparatus comprising: an aerosol can of the type having an aerosol valve internal to the aerosol can, the aerosol valve having a valve seat that moves reciprocally within a valve housing, and a valve spring that urges the valve seat toward a closed position within the valve housing, the aerosol can containing a pressurized gas; and a pressure regulator connected to the aerosol can, the pressure regulator having a regulator housing, a cylinder within the regulator housing, a piston movable within the cylinder, a pressure chamber located between the piston and the aerosol valve, a gas outlet in fluid connection with the pressure chamber, a valve actuator rod extending from the piston toward the valve seat of the aerosol valve, and a regulator spring urging the piston and valve actuator rod toward the valve seat of the aerosol valve, thus urging the valve seat toward an open position within the valve housing.

13. The apparatus of claim 12, wherein the aerosol can has an externally threaded portion and the regulator housing has an internally threaded portion for connecting the pressure regulator to the aerosol can.

14. The apparatus of claim 12, further comprising a flow restrictor having a known resistance to fluid flow in fluid connection with the gas outlet.

15. The apparatus of claim 12, further comprising a flow restrictor having an adjustable resistance to fluid flow in fluid connection with the gas outlet.

16. The apparatus of claim 12, further comprising a pressure adjustment screw for adjusting a preload force on the regulator spring, thereby adjusting a set pressure of the pressure regulator.