HK1197906A - Pressurized screw system using air locks for waste disposal - Google Patents

Description

Pressurized screw system for waste treatment using air lock

Technical Field

The present invention relates generally to waste treatment and more particularly to a method and apparatus for potentially infectious waste treatment that can operate at different atmospheric pressures.

Background

Typically, biohazardous materials or pests must be safely disposed of. For example, biohazardous materials are present at commercial or government waste processing facilities, in hospitals and other medical facility sites. In addition, infectious or potentially infectious waste and pests that threaten agriculture and ecosystem can enter the united states from international arrivals on international flights, international ships, and private ships. These types of waste are often referred to as quarantine waste. Disposal of biohazards and/or quarantine waste and pests on site may prevent expensive transportation costs and the risks associated with these costs. In the case of hazardous materials intercepted at the us entry port, on-site processing can also be a powerful tool. The rapid and reliable handling of infectious or potentially infectious material can mitigate or avoid catastrophic outbreaks.

When dealing with infectious waste for disposal, it is important to ensure that the final waste product to be discarded is free of pathogenic microorganisms. It is also desirable, and in some cases required by the law, to subject the waste material to conditions such that individual components (e.g., disposable syringes, bandages, bodily fluid receivers, and body parts) are not identifiable.

Potential waste treatment methods include incineration, autoclaving, microwave sterilization or other non-incineration treatment methods, with autoclaving and incineration being the most common. Environmental regulations have severely limited the use of incineration to treat waste, and alternative treatment methods (primarily steam autoclaving) are often used as an alternative. Typical problems associated with gravity and vacuum autoclaving include the need for large amounts of high pressure (> 1 bar) steam. These pressure vessels require: initial and continued certification to ensure pressure vessel integrity; the cooling tower cools the autoclave at the end of the cycle; batch only (discontinuous feed) systems. The treated waste material from the high pressure autoclave is very wet and heavy, resulting in increased treatment costs. Some of the available methods are not entirely effective for destroying pathogenic organisms. Some processes (e.g., autoclaving) are "batch" processing systems that are operationally inefficient. Batch processing systems limit processing throughput and therefore require storage of unprocessed material while the batch is "cooking", creating additional demands on the user. Most batch processing methods require equipment that tends to be expensive to install and both expensive and labor intensive to operate. Still other problems with current methods include malodors, toxic gases, liquids, and solid particles that are vented to the atmosphere or released into the sanitary sewage system. For example, certain plastics, when in a semi-solid state, can release Volatile Organic Compounds (VOCs), which are harmful to health and the environment.

Some regulations require a treatment temperature of 212 ° F for a specified period of time. Current steam sterilization systems designed to operate at atmospheric pressure cannot operate at the correct temperature when they are located at different altitudes above sea level. In most thermodynamic processes, the temperature of the system is directly proportional to the pressure of the system, such that changes in system pressure result in changes in system temperature. For example, an atmospheric steam processing system at 5000 feet MSL operates at a relatively reduced pressure and, correspondingly, a reduced temperature, in some cases below 212 ° F.

Therefore, there is a need for a continuous feed (non-batch process) steam sterilization system that is capable of operating at elevated altitudes while maintaining a gauge pressure that is equal to or greater than atmospheric pressure at sea level in order to maintain the necessary system temperature of 212 ° F.

Disclosure of Invention

The waste treatment system disclosed herein provides a novel method to treat potentially infectious waste. The waste treatment system employs a combination of continuous throughput (non-batch processing), physical destruction, elevated temperature and low pressure steam to remove biohazards associated with hazardous waste materials (e.g., to steam kill bacteria). By using pressurized steam, it is possible to completely eliminate living microorganisms. The apparatus provides a product which is reduced in volume by up to 90% (compaction), held safely in a conventional bulk waste container, and transported in a conventional garbage truck or roll-on container for disposal in a landfill or similar facility. The treatment system also incorporates a subsystem that allows the introduction of odor control chemicals to reduce offensive odors while the system is operating.

The waste treatment system includes several components that are used to introduce and treat infectious waste in a continuous manner (high efficiency operation) so that the waste material is no longer infectious. The system includes a steam chamber having an elongated enclosure provided with pressure locks at both ends. A rotatable conveyor is positioned within the enclosure. A hopper and an optional shredder are positioned at one end of the enclosure. A discharge region is positioned at the other end of the enclosure.

The hopper receives waste material and feeds it into the shredder. An optional shredder physically breaks down the waste material before it enters the enclosure. An odor control chemical solution is optionally applied to the waste once the material has passed through the shredder.

A rotatable conveyor is positioned throughout the length of the enclosure. The rotatable conveyor is driven by an external drive means. A series of steam injection valves are positioned within the enclosure and are configured to deliver steam directly to the pulverized waste material being conveyed by the conveyor. A steam jacket is positioned around a portion of the enclosure. Waste material traveling through the enclosure is subjected to steam having a minimum temperature of 212 ° F or greater for a specified period of time.

The feed pressure lock is located at the inlet end of the closure and includes a top feed valve and a bottom feed valve. Positioned at the other end of the enclosure (and rotary conveyor) is a discharge pressure lock having a top discharge valve and a bottom discharge valve. The two valves at each end of the rotary conveyor constitute a pressure lock at each end. In one configuration, the valve is a slide-type valve that is engaged by a drive motor. Sliding-type valves are flat structures that can be slid into a position that sealingly isolates each side of the valve from the opposite side.

In a first configuration, the inlet pressure lock is configured to receive waste material at atmospheric pressure. Meanwhile, the outlet pressure lock is configured to receive the waste material at a gauge pressure (or internal pressure of the chamber). The pressure lock may be activated and moved from a first configuration to a second configuration. In a second configuration, the inlet pressure lock is configured to convey waste material to the conveyor and the outlet pressure lock is configured to convey waste material through the discharge opening.

The waste treatment system maintains the required pressure within the enclosure through proper operation of the pressure lock. As used in pressure locks, the valve can create a pressure lock area that is positioned between the interior of the enclosure and the exterior of the enclosure. The material may be transferred between the interior and the exterior while substantially maintaining a pressure differential between the interior and the exterior. In each operating situation, at least one of the two stackable valves at each end of the rotary steam conveyor is closed. There is no point during operation where both valves at a given end (feed end or discharge end) are open at the same time. In this way, the valve provides a continuous pressure seal between the interior of the enclosure and the outside atmosphere. The system operates in a substantially continuous manner without interruption caused by the pressure lock valve switching position.

During processing, waste material moves from the feed pressure lock, engages the conveyor, and travels through the enclosure in response to the conveyor component driving force. The waste is exposed to high temperatures and treated with low pressure (< 1 bar) steam while traveling through the enclosure. The screw type conveyor subjects the waste material to agitation and maximum exposure to steam. The process continues while the pressure lock operates to move material between the interior and exterior of the enclosure.

The combination of the feed pressure lock and the discharge pressure lock allows the steam within the enclosure to be maintained at a pressure above the external atmospheric conditions. Accordingly, the temperature of the vapor is dependent on the internal pressure of the enclosure, rather than the external atmospheric pressure. The waste treatment system may be operated at a pressure and temperature that is independent of the atmospheric pressure at the location of the waste treatment system. For example, the waste treatment system may be operated in multiple areas of the state of colorado, where the altitude may be above 5,000 feet above sea level, while always maintaining internal waste temperatures at or above 212 ° F (100 ℃).

In an alternative example, the waste treatment system may include rotary valves in the feed and discharge pressure locks. The rotary valve is rotatable about an axis through a plurality of configurations in which the pressure lock is alternately exposed to the outside atmosphere and the interior of the vapor chamber. The rotary valve provides a pressure seal between the interior of the steam chamber and the outside atmosphere while facilitating movement of the waste material into and out of the steam chamber. The rotary valve provides the same function to the waste treatment system as the slide valve and may be similarly advantageous. The rotary valve can be employed as a mechanical feeding device without directly exposing the interior of the enclosure to atmospheric pressure.

Still other aspects, objects, features, aspects, benefits, advantages, and embodiments of the present disclosure will become apparent from the drawings and detailed description provided herein.

Drawings

Figure 1 is a schematic cross-sectional view of a waste treatment system wherein a feed pressure lock has an open top feed valve and a closed bottom feed valve and a discharge pressure lock has an open top discharge valve and a closed bottom discharge valve.

Figure 2 is a schematic cross-sectional view of a waste treatment system wherein the feed pressure lock has a closed top feed valve and an open bottom feed valve and the discharge pressure lock has a closed top discharge valve and an open bottom discharge valve.

Figure 3 is a schematic cross-sectional view of an alternative example of a waste treatment system in which the feed pressure lock has a rotary valve and the discharge pressure lock has a rotary valve.

FIG. 4 is a cross-sectional schematic view of the example of FIG. 3, showing the rotary valve in an alternative configuration.

Detailed Description

For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to the examples illustrated in the drawings and specific language will be used to describe the same. It should be understood, however: and are not intended to limit the scope of the present disclosure thereby. Any alterations and further modifications in the described examples, and any further applications of the principles of the disclosure as described herein are contemplated as would normally occur to one skilled in the art to which the disclosure relates. Certain examples of the disclosure are shown in sufficient detail, but those skilled in the relevant art will appreciate that certain features that are not relevant to the disclosure may not be shown for the sake of brevity.

Waste treatment systems for treating infectious or potentially infectious waste material are disclosed herein. The system includes a chamber 100 having a feed pressure lock 102 at one end and a discharge pressure lock 104 at the other end (fig. 1). An optional shredder 106 is positioned adjacent to the feed pressure lock 102. Hopper 114 is positioned adjacent shredder 106. Positioned within the chamber 100 is a conveyor 108. Steam jacket 110 is positioned circumferentially around the outer region of chamber 100. Positioned within the chamber 100 is an injector 112.

As a general overview of waste treatment systems, the system destroys and purifies waste material by subjecting it to moist steam heat directly in a pressurized environment. Optionally, a comminution apparatus is used in combination with the present system. Waste material is placed into hopper 114, which feeds the material into shredder 106. Waste material enters the feed pressure lock 102 from the shredder 106. The feed pressure lock 102 continuously seals the inlet of the chamber 100. The feed pressure lock 102 is activated to fluidly isolate the waste material from the exterior of the enclosure and to facilitate the introduction of the waste material into the chamber 100. The conveyor 108 advances waste material through the chamber 100 while undergoing an agitation motion. The waste material is subjected to steam supplied from the ejector 112 and heat from the steam jacket 110. At the outlet of the chamber 100, the waste material enters a discharge pressure lock 104. The discharge pressure lock 104 continuously seals the outlet of the chamber 100. The discharge pressure lock 104 is activated to fluidly isolate the waste material from the chamber 100 and facilitate movement of the waste material out of the waste treatment system.

The waste treatment system includes several components, which are described in more detail herein. The chamber 100 includes an elongated enclosure 116 having an inlet opening 118 at one end for receiving waste material and an outlet opening 120 at an opposite end for conveying processed waste material. Elongated closure 116 has a cylindrical inner wall 122.

The conveyor 108 extends through the elongated enclosure 116 between a feed opening 118 and a discharge opening 120. The conveyor 108 is preferably a auger-type conveyor or an auger-type conveyor having a helical blade 124 attached to a shaft 126. The screw rod comprises a continuous helical ladder (archimedes spiral) along a substantial portion of the shaft 126. Conveyor 108 is rotatably mounted at hub 128 adjacent to feed opening 118 and discharge opening 120. The hub 128 may include bearings or bushings that are sealed and provide an atmospheric pressure seal between the outside atmosphere and the interior of the chamber 100. The carrier 108 fits into the elongated enclosure 116 with a small gap between its vanes 124 and the inner wall 122 of the enclosure 116. Conveyor 108 is driven by a conveyor drive 130, which is rotatably connected to shaft 126 by a chain and gears or other means. The transporter drive 130 imparts rotational motion to the transporter 108. The rotatability and helical shape of the conveyor 108 enables the waste material to be transported from the feed opening 118 through the closure body 116 to the discharge opening 120.

In the example of fig. 1, the feed pressure lock 102 is positioned between the shredder 106 and the feed opening 118. The feed pressure lock 102 facilitates the temporary storage and transport of waste material from the shredder 106 through the feed opening 118 and into the chamber 100. The feed pressure lock 102 includes a top feed valve 132 and a bottom feed valve 134. The top feed valve 132 is positioned adjacent the shredder outlet of the shredder 106. Bottom feed valve 134 is positioned adjacent to feed opening 118. In certain embodiments, top feed valve 132 and bottom feed valve 134 are slide valves that are slidable between an open position and a closed position. The feed pressure lock 102 includes a slide channel 136. Top feed valve 132 and bottom feed valve 134 are movable along slide channel 136 between open and closed positions. The top feed valve 132 provides a reciprocating fluid seal between the shredder 106 and the interior 138 of the feed pressure lock 102 (which serves as a space for collecting waste). Similarly, the bottom feed valve 134 provides a reciprocating fluid seal between the chamber 100 and the interior 138 of the feed pressure lock 102.

The discharge pressure lock 104 is positioned between the discharge opening 120 and the discharge outlet 140. The discharge pressure lock 104 facilitates temporary storage and transfer of the treated waste material from the discharge opening 120 to the discharge outlet 140. The discharge pressure lock 104 functions similarly to the feed pressure lock 102 and includes a top discharge valve 142 and a bottom discharge valve 144. The top discharge valve 142 is positioned adjacent the discharge opening 120. The bottom discharge valve 144 is positioned adjacent the discharge outlet 140 (or adjacent the inlet of the discharge outlet 140). In some embodiments, top discharge valve 142 and bottom discharge valve 144 are slide valves that are slidable between an open position and a closed position. The discharge pressure lock 104 includes a slide channel 146. Top discharge valve 142 and bottom discharge valve 144 are movable along slide channel 146 between an open position and a closed position. The top discharge valve 142 provides a reciprocating fluid seal between the discharge opening 120 and the interior 148 of the discharge pressure lock 104 (which serves as a space for collecting waste). Similarly, bottom discharge valve 144 provides a reciprocating fluid seal between interior 148 and discharge outlet 140.

The feed and discharge valves of the feed pressure lock 102 and the discharge pressure lock 104 may be any of a variety of types of industrial slide valves known in the art and suitable for the present application. These valves are commercially available and can provide a reciprocating fluid seal as described herein. One example of such a valve is the BC (ser.90) square-nose knife gate valve from Orbinox corporation, which may be incorporated into the system described herein.

The valves of the feed pressure lock 102 and the discharge pressure lock 104 are each engaged by a driver 150. The actuator 150 provides translational movement to each of the valves and moves the valves between open and closed positions. The drive 150 may be an electric motor, a hydraulic motor, or any of a variety of devices known in the art.

Optional shredder 106 may be of any make and configuration suitable for shredding waste material. The shredder 106 typically employs a cooperating rotating cutter 152 that shreds the waste material. The crushed waste material is reduced in size and has an increased overall surface area that enhances vapor permeation. The shredder 106 may be made in a variety of configurations, which may be selected depending on the material to be processed. For example, it may comprise a one-, two-, or four-axis morcellator, or a plurality of two-axis morcellators or any of a variety of morcellator configurations. Shredder 106 includes a hopper 114 connected to a top portion of shredder 106. Hopper 114 includes a necked shape such that the portion attached to shredder 106 is smaller than the opening of hopper 114. The shredder outlet is positioned at the base of the shredder 106 adjacent to the top feed valve 132 of the feed pressure lock 102.

One or more conduits connect from a low pressure steam source to the interior of enclosure 116 to bring the steam into direct contact with the waste material. The chamber 100 includes a plurality of injectors 112 fluidly connected to the conduit. Four injectors 112 are shown in fig. 1, however, more or fewer injectors 112 may be present. The injectors 112 are spaced apart from one another in the longitudinal direction at a plurality of locations between the feed opening 118 and the discharge opening 120. Additional injectors 112 may be added longitudinally as well as circumferentially around the enclosure 116. The ejectors 112 are positioned to carry the steam to the waste material at multiple locations within the chamber 100, such that the waste material is exposed to direct impingement of the steam source multiple times. The source of steam may be any suitable source of steam, such as a boiler or steam generator. The conduit may be configured in a variety of configurations relative to the connectivity of the injector 112 through the conduit to the steam source. For example, the injectors 112 may each be configured to provide steam and chemicals for odor control simultaneously. The arrangement may also be configured such that the eductor 112 carries only steam or a combination of steam and odor control chemicals.

Steam jacket 110 surrounds a portion of enclosure 116. The steam jacket 110 has an interior region defined by an inner wall and an outer wall and is capable of holding steam. Steam jacket 110 receives steam from the same steam source that supplies steam to ejector 112. Steam jacket 110 abuts an outer surface of closure 116, or alternatively, steam jacket 110 is integral with closure 116. Steam jacket 110 maintains the temperature of the steam from the steam source (typically 240-245 degrees fahrenheit (< 1 bar pressure) and provides the heat source to the interior of chamber 100.

A pressure relief valve 154 is incorporated into the chamber 100. The pressure relief valve 154 is in fluid communication with the interior of the chamber 100 and is capable of maintaining the internal pressure of the chamber 100. The pressure relief valve 154 may be of any type suitable for engaging and relieving pressure within the container when a defined internal pressure is exceeded.

The waste treatment system described herein provides a novel way to treat waste material. Prior systems include augers that operate at atmospheric pressure or reduced pressure within the enclosure. The new system provides a pressurized treatment system that allows for achieving higher internal temperatures than those achieved at atmospheric pressure. The system does not require an ANSI pressure rated vessel because the system does not operate at pressures greater than 15psig (1 bar). However, the system operates at a pressure sufficient to maintain a temperature equal to or greater than 212 ° F in any event. Furthermore, unlike high pressure high temperature processing systems, the present system is designed to avoid melting plastics, which in a molten or semi-solid state can release Volatile Organic Compounds (VOCs), which are harmful to health and the environment.

The above characteristics are achieved through the use of a feed pressure lock 102 and a discharge pressure lock 104 that provide a way for waste material to enter and exit the chamber 100 while maintaining a pressure differential between the interior of the chamber 100 and the outside atmosphere. Thus, the valve may be positioned in various configurations that enable and maintain a pressure differential between atmospheric pressure and the internal pressure of the chamber 100 while facilitating movement of the waste material through the pressure lock. During the entire operation, at least one of the valves in each pressure lock is closed, so that the interior of the chamber 100 is always fluidly sealed from the outside.

For example, when the top feed valve 132 is in the closed position (fig. 2), the shredder 106 is fluidly sealed from the interior 138, and the interior 138 is also sealed from the surrounding atmosphere. When the top feed valve 132 is in the closed position and the bottom feed valve 134 is in the open position (fig. 2), the feed pressure lock 102 is configured to transport waste material through the feed opening 118.

When the bottom feed valve 134 is in the closed position (fig. 1), the interior 138 is fluidly sealed to the chamber 100. When the bottom feed valve 134 is in the closed position and the top feed valve 132 is in the open position (fig. 1), the interior 138 is fluidly sealed to the chamber 100 and the feed pressure lock 102 is configured to receive waste material from the shredder 106.

When the top discharge valve 142 is in the closed position (FIG. 2), the chamber 100 is fluidly sealed from the interior 148. When the top discharge valve 142 is in the closed position and the bottom discharge valve 144 is in the open position (fig. 2), the discharge pressure lock 104 is configured to transport waste material through the discharge outlet 140.

When bottom discharge valve 144 is in the closed position (fig. 1), interior 148 is fluidly sealed to discharge outlet 140, and interior 148 is also sealed to the surrounding atmosphere. When the bottom discharge valve 144 is in the closed position and the top discharge valve 142 is in the open position (fig. 1), the interior 148 is fluidly sealed to the discharge outlet 140 and the discharge pressure lock 104 is configured to receive the treated waste material through the discharge opening 120. In this way, the pressure differential is always maintained between atmospheric pressure and the internal pressure of the chamber 100.

During operation of the waste treatment system, the uniform pressure region 160 is maintained between the discharge pressure lock 104 and the chamber 100 when in the first configuration (fig. 1). In this configuration, the crushed waste material may accumulate on the surface of the bottom feed valve 134. At the same time, the processed waste material may be deposited on the surface of the bottom discharge valve 144 via the conveyor 108. At an appropriate time, the system may transition from the first configuration to the second configuration (fig. 2). In the second configuration (fig. 2), a uniform pressure region 260 is maintained between the chamber 100 and the interior 138 of the feed pressure lock 102. In this configuration, waste material may be conveyed from within the discharge pressure lock 104 through the discharge outlet 140. Similarly, waste material may be conveyed from within the feed pressure lock 102 through the feed opening 118 to engage the conveyor 108. At the same time, waste material may collect on the surface of the top feed valve 132. The conveyor 108 transports waste material through the enclosure 116 to the discharge opening 120 where it collects on the surface of the top discharge valve 142. When a sufficient amount of waste material has accumulated at the top discharge valve 142 and/or at the top feed valve 132, the waste treatment system may transition from the second configuration (fig. 2) to the first configuration (fig. 1). The process may then be repeated.

The configuration of the valves in the feed pressure lock 102 and the discharge pressure lock 104 allows the waste treatment system to be operated continuously without interrupting the flow of waste through the system. When the waste treatment system is in the first configuration (fig. 1), waste material may enter the feed pressure lock 102 simultaneously and/or at the same rate at which it enters the discharge pressure lock 104. In the second configuration, the waste material may be discharged from the feed pressure lock 102 through the feed opening 118 simultaneously or at the same rate that the treated waste material is discharged from the discharge pressure lock 104 through the discharge outlet 140. The conveyor 108 may continue to transport waste material through the enclosure 116 even while the system transitions between the first and second configurations.

The top and bottom valves of the feed pressure lock 102 and the discharge pressure lock 104 may be operated in a cooperative and consistent manner. For example, the waste treatment system may be changed from the first configuration to the second configuration by first closing the top feed valve 132 and simultaneously closing the top discharge valve 142. Alternatively, the top valves may be operated sequentially. The bottom feed valve 134 may be opened at the same time the bottom discharge valve 144 is opened. Alternatively, the bottom valves may be operated sequentially. This cooperative operation ensures that a pressure differential is maintained between the chamber 100 and the outside atmosphere. Operating the top and bottom valves simultaneously in tandem may also allow the cumulative volume of the chamber 100 to remain constant throughout the operation of the waste treatment system.

The waste material is altered and processed at several points while traveling through the waste processing system. In an optional first step, waste material may be processed by shredder 106. Waste material is first introduced into hopper 114, which may take a variety of forms, such as baled or boxed biological material, and the like. The necked portion of hopper 114 directs waste into shredder 106. Shredder 106 performs various functions. The rotary cutters 152 in the shredder 106 operate in concert to physically shred waste material. Shredder 106 removes any packaging that wraps around the waste material and shreds the packaged waste. The shredder 106 breaks down the waste material into smaller portions having relatively uniform particle sizes, which increases the amount of exposed surface area of the waste material. The comminution process may be enhanced by providing a pneumatically operated ram or other assisting device that applies downward pressure to the waste material in hopper 114 to more forcefully engage rotary cutter 152.

The system allows for optional chemical treatment of waste materials. The odor control solution may be added to the waste material at several points. The optional direct impingement of the heated atmosphere and steam onto the waste material in the chamber 100 helps to ensure complete destruction of viable microorganisms. Moisture introduced into the waste material by direct steam impingement can be removed by dewatering.

Waste material is transferred by gravity from the feed pressure lock 102 through the feed opening 118 to the end of the conveyor. When rotated, the conveyor 108 transports waste material (a function of the spiral shape of the conveyor) from the feed opening 118, through the closure 116, to the discharge opening 120. The conveyor 108 transports and mixes the waste material to enhance the permeability of the vapor to the waste material.

The steam is applied to the waste material through the ejector 112 at multiple points along the length of the conveyor 108. In addition, heat is supplied through steam jacket 110. The steam is maintained at or above normal atmospheric pressure and the temperature is maintained at or above 212 ° F. Steam jacket 110 is maintained at a temperature such that the surface of the inner wall of enclosure 116 is maintained at a temperature at or above 212 ° F. The combination of steam jacket 110 and eductor 112 quickly raises the temperature of the waste material within enclosure 116 to a temperature equal to or greater than the boiling point of water at any altitude above sea level. The waste material is exposed to the vapor via the ejector 112 that protrudes into the interior of the enclosure 116.

The mixing action of the conveyor 108 ensures that the steam comes into contact with all or substantially all surfaces of the waste material and the heating ensures that infectious microorganisms are completely killed. The conveyor 108 agitates and tumbles the waste material to enhance contact between the steam and the waste material. Similarly, the action of conveyor 108 ensures good contact between the waste and the heated cylindrical inner wall 122 of enclosure 116. The close fit of the helical blade of the conveyor 108 with the inner wall of the enclosure 116 ensures that the waste material is maintained in contact with the heated inner wall 122 at least intermittently. A mixing tab (not shown) may be provided on the conveyor 108 to enhance the permeability of the vapor to waste. The speed of the conveyor 108 is controlled such that the residence time of the waste material in the chamber 100 is long enough to adequately treat the waste material and comply with relevant regulations (e.g., 30 minutes).

Steam jacket 110 may provide further processing of the waste material, including contact with hot surfaces, such that moisture in the waste material is converted to steam. Steam jacket 110 may additionally provide a means to dehydrate the waste material, thereby separating recyclable moisture from the waste material and reducing the volume of the waste material.

Steam is introduced at a pressure that is maintained at sea level atmospheric pressure (-15 psig) such that the corresponding temperature is maintained at or above 212 deg.f. The unique pressure lock system described herein ensures that the pressure within the steam chamber can be maintained constant while introducing and removing waste material relative to the steam chamber. This is advantageous, particularly for applications at high altitudes (e.g., some places in the state of colorado), where the atmospheric boiling temperature is low relative to the atmospheric pressure drop at sea level. The waste treatment system is uniquely suited to operation at elevated temperatures while complying with current regulations (e.g., up to 30 minutes at 212 ° F). Because the steam is maintained at approximately 15psig, the waste treatment system does not require ANSI rated high pressure vessels.

The pressure relief valve 154 assists in controlling the pressure within the chamber 100. During operation of the waste treatment system, energy is added to the system through the use of the eductor 112. The pressure within the chamber 100 is controlled and maintained by use of a pressure relief valve 154. The pressure relief valve 154 vents air or vapor if the internal pressure of the chamber 100 exceeds a predetermined threshold limit, such as 15 psig.

The treated waste material is discharged through the discharge outlet 140. The discharge may include a flapper valve connected to a counterweight that normally maintains the discharge opening 120 in a closed state. As the waste material accumulates in the discharge outlet 140, the flap opens under the weight of the waste material, allowing the waste material to be discharged to an appropriate discharge area, such as a conveyor belt or compactor. From there, the treated waste material can be safely transported to a landfill or any other suitable landfill site.

The waste treatment system may include any number of sensors that can monitor temperature, pressure, and other conditions at various points within the system. For example, the temperature of the steam in steam jacket 110 may be controlled by a thermocouple (not shown) positioned on or within steam jacket 110 and operating a valve to control the flow of steam. Further, a thermocouple may be disposed on a surface of enclosure 116. The thermocouple may operate a valve (not shown) that controls the steam flow to maintain the temperature of the waste material at the necessary 212 ° F.

An alternative example of a waste treatment system is shown in figures 3 and 4. The waste treatment system operates as previously disclosed, except for the feed and discharge pressure locks. The waste treatment system has a feed pressure lock 302 and a discharge pressure lock 304. The feed pressure lock 302 includes a feed rotary valve 306 and the discharge pressure lock 304 includes a discharge rotary valve 308. The rotary valve provides a similar function to the feed and discharge valves of the example of figures 1 and 2.

Rotary valves 306 and 308 may be any of a variety of designs. In the example of fig. 3, the feed rotary valve 306 has a portion that is rotatable about an axis 310 and is positionable in a plurality of rotational positions about the axis 310. The feed rotary valve 306 has four blades 312. The vanes 312 are configured to sealingly interact with a curved surface 314. At any point during the rotation of the feed rotary valve 306, the at least two vanes 312 sealingly interact with the curved surface 314 such that the chamber 100 is always fluidly sealed from the outside atmosphere. In the first configuration (fig. 3), at least two of the vanes 312 are oriented in a generally vertical orientation, and waste material accumulates in two of the four compartments 316 defined by the intersection of the vanes 312. As the vanes 312 rotate from the first configuration (in this case, for example, in a counterclockwise direction relative to the perspective of fig. 3) to the second configuration (fig. 4), the two compartments 316 become fluidly isolated from the chamber 100 and the outside atmosphere. Isolated compartment 316 is defined by curved surface 314 and vanes 312. One of the isolated compartments 316, which is exposed at the front to the shredder outlet, contains waste material and has a pressure equal to the pressure of the outside atmosphere. The other isolated compartment 316 is exposed at the front to the feed opening 118, does not contain waste material, and has a pressure equal to the internal pressure of the chamber 100.

As the vanes 312 are further rotated (from the configuration of fig. 4 to the configuration of fig. 3), the accumulated waste material is transported along the curved surface 314 until one of the vanes 312 does not contact the surface 314, thereby causing the compartment 316 to become pressurized in conformity with the internal pressure 360 (fig. 3) of the chamber 100 and the waste material is deposited through the feed opening 118. Simultaneously, adjacent compartments 316 receive waste material, which is then transported along curved surface 314, and the process is repeated.

The discharge rotary valve 308 operates in a similar manner to the feed rotary valve 306 and includes a vane 312 that is rotatable about an axis 318. The discharge rotary valve 308 receives waste material at an internal pressure 460 of the chamber 100 (fig. 4). As the vanes 312 of the discharge rotary valve 308 rotate, waste material accumulates in one of the four compartments 316. As the vanes 312 are further rotated, the accumulated waste material is transported along one of the curved surfaces 314 within one of the compartments 316 until one of the vanes 312 does not contact the surface 314. The compartment 316 then becomes pressurized to the outside atmospheric pressure and waste material is deposited through the discharge outlet 140.

The rotary valves 306 and 308 may be operated simultaneously in any manner that allows for continuous operation of the conveyor 108. Rotary valves 306 and 308 may be rotatably driven by an electric drive motor or any of a variety of suitable motion-driven devices (not shown). The example waste treatment system of fig. 3 and 4 operates in a similar manner to the waste treatment system disclosed previously and shown in fig. 1 and 2, except for rotary valves 306 and 308. The configuration of fig. 3 corresponds to the configuration of fig. 1, while the configuration of fig. 4 corresponds to the configuration of fig. 2.

Rotary valves 306 and 308 are not limited to the configurations described herein and may be any of a variety of industrial rotary valves, which are well known in the art and suitable for the present application. Such valves are available and are capable of providing a fluid seal as described herein. In addition to the sliding and rotary valves described herein, other valve types and configurations are also contemplated as part of the present disclosure. As one non-limiting example, the sliding valves may each be individually replaced by butterfly valves.

Various modifications may be made to the waste treatment system described herein. For example, conveyor 108 may comprise a belt conveyor or two or more sections that are separately controlled. Other design choices such as alternative materials and dimensions are included within the scope of the present disclosure.

While the disclosure has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that: only the preferred examples have been shown and described, and all changes, equivalents, and modifications that come within the spirit of the invention as defined by the following claims are desired to be protected.

Claims (19)

1. A waste treatment system for treating waste material, comprising:

a closure body having an interior and including a feed opening at one end and a discharge opening at another end;

a conveyor positioned between the feed opening and the discharge opening;

a source of steam and a conduit connected from the source of steam to an interior of the enclosure;

a feed pressure lock chamber positioned adjacent to the feed opening; and

a discharge pressure lock chamber positioned adjacent to the discharge opening.

2. The waste treatment system of claim 1, further comprising: a discharge outlet and a shredder having a shredder outlet, wherein the feed pressure lock chamber comprises a top feed valve slidably positioned adjacent the shredder outlet and a bottom feed valve slidably positioned adjacent the feed opening, and wherein the discharge pressure lock chamber comprises a top discharge valve slidably positioned adjacent the discharge opening and a bottom discharge valve slidably positioned adjacent the discharge outlet.

3. The waste treatment system of claim 2, wherein the bottom feed valve is slidable between an open position and a closed position;

wherein, when in a closed position, the interior is fluidly sealed to the feed pressure lock chamber; and is

Wherein, when in the open position, the feed pressure lock chamber is in fluid communication with the interior.

4. The waste treatment system of claim 2, wherein the top feed valve is slidable between an open position and a closed position;

wherein, when in the closed position, the feed pressure lock chamber is fluidly sealed from the external atmosphere; and is

Wherein, when in the open position, the feed pressure lock chamber is in fluid communication with the external atmosphere.

5. The waste treatment system of claim 2, wherein the top discharge valve is slidable between an open position and a closed position;

wherein, when in a closed position, the discharge pressure lock chamber is fluidly sealed to the interior; and is

Wherein, when in the open position, the discharge pressure lock chamber is in fluid communication with the interior.

6. The waste treatment system of claim 2, wherein the bottom discharge valve is slidable between an open position and a closed position;

wherein, when in the closed position, the discharge pressure lock chamber is fluidly sealed from the external atmosphere; and is

Wherein, when in the open position, the discharge pressure lock chamber is in fluid communication with the outside atmosphere.

7. The waste treatment system of claim 1, wherein the feed pressure lock chamber comprises a rotary valve.

8. The waste treatment system of claim 7 wherein the rotary valve is rotatable about an axis through a plurality of rotational positions;

wherein, in each rotational position, the rotary valve provides a fluid seal between the interior and the external atmosphere;

the rotary valve further comprising a compartment for receiving waste material; and is

Wherein, during rotation, the compartment rotationally carries waste material from the external atmosphere to the interior about the axis.

9. The waste treatment system of claim 1 wherein the discharge pressure lock chamber comprises a rotary valve.

10. The waste treatment system of claim 9, wherein the rotary valve is rotatable about an axis through a plurality of rotational positions;

wherein, in each rotational position, the rotary valve provides a fluid seal between the interior and the external atmosphere;

the rotary valve further comprising a compartment for receiving waste material; and is

Wherein, during rotation, the compartment rotationally transports waste material from the interior to the external atmosphere about the axis.

11. The waste treatment system of claim 1, wherein the conveyor is an auger-type conveyor having helical blades.

12. The waste treatment system of claim 1, further comprising: a steam jacket positioned circumferentially around a portion of an outer surface of the closure.

13. A method for processing waste material, comprising:

adding waste material to a feed pressure lock chamber that is fluidly exposed to an exterior at atmospheric pressure;

fluidly isolating the waste material from the exterior;

moving the waste material from the feed pressure lock chamber to an enclosure having an interior, wherein the interior is fluidly sealed to the exterior;

conveying the waste material from the feed opening of the enclosure to a discharge opening of the enclosure;

treating the waste material with steam;

moving the waste material to a discharge pressure lock chamber, wherein the discharge pressure lock chamber is fluidly exposed to the interior;

fluidly isolating the waste material from the interior; and

fluidly exposing the waste material to the exterior, wherein the interior is always fluidly isolated from the exterior during waste treatment.

14. The method of claim 13, further comprising the steps of: adding the waste material to a shredder having a shredder outlet.

15. The method of claim 14, further comprising: a discharge outlet;

wherein the feed pressure lock chamber comprises a top feed valve slidably positioned adjacent the shredder outlet and a bottom feed valve slidably positioned adjacent the feed opening; and is

Wherein the discharge pressure lock chamber comprises a top discharge valve slidably positioned adjacent the discharge opening and a bottom discharge valve slidably positioned adjacent the discharge outlet.

16. The method of claim 13, wherein the feed pressure lock chamber comprises a feed rotary valve, and wherein the discharge pressure lock chamber comprises a discharge rotary valve;

wherein the feed rotary valve is rotatable about a first axis through a plurality of first rotational positions;

wherein, in each first rotational position, the feed rotary valve provides a fluid seal between the interior and the exterior;

the rotary valve further comprises a first compartment for receiving waste material;

wherein, during rotation, the first compartment transports the waste material from the exterior to the interior about the axis;

wherein the discharge pressure lock chamber comprises a discharge rotary valve;

wherein the discharge rotary valve is rotatable about a second axis through a plurality of second rotational positions;

wherein, in each second rotational position, the discharge rotary valve provides a fluid seal between the inner portion and the outer portion;

the discharge rotary valve further comprises a second compartment for receiving the waste material; and is

Wherein, during rotation, the second compartment transports the waste material from the interior to the exterior about the axis.

17. A waste treatment system for treating biological material, comprising:

an elongated enclosure having an interior and including an inlet opening positioned at one end for receiving waste material and an outlet opening positioned at the other end for delivering processed waste material;

a conveyor for moving waste material from the feed opening through the enclosure to the discharge opening, wherein the conveyor is an auger-type conveyor having a helical blade;

a source of steam and a conduit connected from the source of steam to an interior of the enclosure;

a discharge outlet;

a feed pressure lock chamber positioned adjacent to the feed opening;

a discharge pressure lock chamber positioned adjacent to the discharge opening; and is

Wherein the feed pressure lock chamber comprises a top feed valve slidably positioned adjacent the shredder outlet and a bottom feed valve slidably positioned adjacent the feed opening; and is

Wherein the discharge pressure lock chamber comprises a top discharge valve slidably positioned adjacent the discharge opening and a bottom discharge valve slidably positioned adjacent the discharge outlet.

18. The waste treatment system of claim 17, further comprising: an injector connected to the conduit and positioned in fluid communication with the interior, and wherein the injector supplies steam to the material within the enclosure.

19. The waste treatment system of claim 17, further comprising: a steam jacket positioned to surround a portion of the enclosure, and wherein the steam jacket is positioned to supply thermal energy to the interior.