System and method for concentrating gas

Abstract

To provide a system and a method for concentrating gas.SOLUTION: Systems and methods are provided that obtain the same or better level of performance by using lower operating flow rates, pressures and / or optimized flow distributions within the system. This extends the life of system components and lower energy consumption. In one embodiment, gas separation (or sieve) beds that are used to separate gaseous components are provided that have lower flow and pressure requirements compared to conventional beds. The sieve beds include, for example, a diffuser having a low solid area in cross-section and a maximum open area for flow while providing adequate mechanical properties to contain a sieve material and support filter media. In another embodiment, systems and methods are provided having an indicator when a component has been serviced or repaired.SELECTED DRAWING: Figure 17-1

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the priority of U.S. Provisional Patent Application No. 63 / 052,694 (Attorney Docket No. 12873 - 07004) filed on July 16, 2020, entitled "System and Method for Concentrating Gas", and U.S. Provisional Patent Application No. 63 / 212,920 (Attorney Docket No. 12873 - 07156) filed on June 21, 2021.

[0002] This application incorporates by reference the following patent applications, all filed on July 16, 2020: U.S. Provisional Patent Application No. 63 / 052,694 (Attorney Docket No. 12873 - 07004) entitled "System and Method for Concentrating Gas", U.S. Provisional Patent Application No. 63 / 052,700 (Attorney Docket No. 12873 - 07033) entitled "System and Method for Concentrating Gas", U.S. Provisional Patent Application No. 63 / 052,869 (Attorney Docket No. 12873 - 07041) entitled "System and Method for Concentrating Gas", U.S. Provisional Patent Application No. 63 / 052,533 (Attorney Docket No. 12873 - 07043) entitled "System and Method for Concentrating Gas", and U.S. Provisional Patent Application No. 63 / 052,647 (Attorney Docket No. 12873 - 07044) entitled "System and Method for Managing Medical Devices", and U.S. Provisional Patent Application No. 63 / 212,920 (Attorney Docket No. 12873 - 07156) entitled "System and Method for Concentrating Gas" filed on June 21, 2021.

Background Art

[0003] There are various applications related to the separation of gaseous mixtures. For example, the separation of nitrogen from atmospheric air can provide a source of high-concentration oxygen. These various applications include the provision of high-concentration oxygen for medical patients and aviators. Therefore, it is desirable to provide a system for separating a gaseous mixture to provide a concentrated product gas such as a breathing gas with a certain concentration of oxygen.

[0004] For example, some existing product gas or oxygen concentration systems and methods are co-assigned to Invacare Corporation (Elyria, Ohio) and are hereby incorporated herein by reference in their entirety: U.S. Pat. Nos. 4,449,990, 5,906,672, 5,917,135, 5,988,165, 7,294,170, 7,455,717, 7,722,700, 7,875,105, 8,062,003, 8,070,853, 8,668,767, 9,132,377, 9,266,053, and 10,010,696.

[0005] Such systems are known to be either stationary, transportable, or portable. A stationary system is intended to remain in one location, such as a user's bedroom or living room, for example. A transportable system is intended to be moved from place to place and often includes wheels or other mechanisms to facilitate the movement. A portable system is intended to be carried with the user, for example, via a shoulder strap or similar accessory.

[0006] Gas concentration systems typically generate dynamic flows and pressures within their operating components as part of the separation and concentration processes. These flows and pressures are necessary, but they also affect the mechanical wear and lifespan of the system components. Generally, the higher the required flows and pressures within the system, the greater their impact on the mechanical wear and lifespan of the system components. Also, the higher the required flows and pressures within the system, the greater the amount of energy that needs to be consumed to generate the required flows and pressures. What is desired is a system that addresses these and other aspects of gas separation and concentration systems.

[0007] In another aspect, gas concentration systems require inspections during their lifespan. Various gas separation components need to be either replaced, repaired, or inspected. Manufacturers have a need to know when such components are inspected outside the manufacturer's territory. What is desired is a system that also addresses this aspect of gas separation or concentration systems. Summary of the Invention Means for Solving the Problems

[0008] A gas concentration system and method are provided. In one embodiment, a system and method are provided that achieve the same or better levels of performance by using lower operating flow rates and pressures within the system. This extends the life of system components and reduces energy consumption. In one embodiment, a gas separation (or sieve) bed used to separate gaseous components is provided that has lower flow and pressure requirements compared to conventional beds. The sieve bed includes, for example, a diffuser that contains sieve material and provides appropriate mechanical properties for supporting the filter media while having a low to medium solid area and a maximum open area for flow in cross-section. This allows for efficient flow of gas into and out of the sieve bed, which reduces pressure loss and energy consumption, reduces dynamic and static pressures on the sieve bed material, improves the life of the sieve bed material, and reduces the rate at which the sieve bed material mechanically fails. Other embodiments are also disclosed.

[0009] In another embodiment, a system and method are provided that have indicators when components are inspected or repaired. This provides an indication of whether a component has been tampered with in any way. This allows the manufacturer to determine whether a component has been inspected, repaired, or tampered with outside the manufacturer's domain. Unauthorized inspection or repair can lead to premature component wear and failure.

[0010] In yet another embodiment, systems and methods are disclosed that have a more uniform or optimized flow distribution of gas entering the sieve bed material and / or a low velocity. The sieve bed cap and / or gas input interface includes a flow modification structure, partition, or protrusion within the flow chamber to more uniformly distribute the flow and reduce the velocity of the gas flow entering the sieve bed material. These structures, partitions, and / or protrusions direct the gas flow entering the adjacent spaces within the inner chamber of the cap / interface, providing a more uniform flow distribution of the gas entering the sieve material. The more uniform flow distribution increases sieve bed efficiency by introducing gas more uniformly into the sieve bed material, thereby limiting or eliminating pockets of sieve material that the gas might not reach if the gas were unevenly distributed when entering the sieve bed material. Also, the reduced gas flow velocity reduces mechanical wear and tear on the sieve bed material that causes dust generation and fluidization of the material.

[0011] One objective is to provide a more efficient gas separation system and method.

[0012] Another objective is to provide a gas separation system and method having a lower flow rate and pressure.

[0013] Another objective is to provide a gas separation system and method having a diffuser component with a low to medium solid area in cross-section, thereby providing a large open area for flow.

[0014] Another objective is to provide a gas separation system and method having a diffuser component with a low to medium solid area in cross-section, thereby providing a large open area for flow while also containing sieve material and providing adequate mechanical properties for supporting the filter media.

[0015] Another object is to provide a gas separation system and method having components for providing at least one tampering indication.

[0016] Another object is to provide a gas separation system and method having at least one sieve bed with a tampering indicator.

[0017] Another object is to provide a gas separation system and method having at least one anti-tampering component.

[0018] Another object is to provide a gas separation system and method having at least one anti-tampering sieve bed.

[0019] Another object is to provide a gas separation system and method that distributes flow into a desired profile for more uniform distribution of gas entering a sieve bed.

[0020] Another object is to provide a gas separation system and method having an input device (e.g., a cap or inserter) for deflecting and / or conditioning flow into a desired profile as gas enters a sieve bed.

[0021] Another object is to provide a gas separation system and method that reduces the flow rate of gas entering a sieve bed material and reduces abrasion and tearing of the sieve material (e.g., dust generation, fluidization, etc.).

[0022] These and other objects, features, and advantages will become apparent after the following description, drawings, and examination of the claims. For example, the present application provides the following items. (Item 1) An input interface for a sieve bed, a body, at least one gas feed port, a chamber for receiving gas from the port, At least one flow modification structure extending from the chamber wall into the chamber, the flow modification structure being positioned juxtaposed to the gas supply port, at least one flow modification structure and having a body and comprising an interface. (Item 2) The interface according to item 1, wherein the at least one flow modification structure comprises a baffle. (Item 3) The interface according to item 1, wherein the at least one flow modification structure comprises ribs. (Item 4) The interface according to item 1, wherein the at least one flow modification structure comprises a gap. (Item 5) The interface according to item 1, wherein the at least one flow modification structure comprises first and second baffles and a gap therebetween. (Item 6) The interface according to item 1, wherein the at least one flow modification structure comprises first and second rows of baffles. (Item 7) The interface according to item 1, wherein the at least one flow modification structure comprises first, second, and third rows of baffles. (Item 8) The interface according to item 1, wherein the at least one flow modification structure comprises first and second rows of baffles and gaps between the baffles of each row. (Item 9) The interface according to item 1, wherein the at least one flow modification structure comprises a first baffle and a second baffle, the second baffle having a curved body. (Item 10) The interface according to item 1, wherein the at least one flow modification structure comprises a first baffle and a second baffle, the first and second baffles having substantially planar bodies. (Item 11) A sieve floor, A container for storing a separation medium, the container having a container wall, A cap having a body, the body comprising: At least one gas feed port, A chamber for receiving gas from the port, At least one flow modification structure extending from the chamber wall into the chamber, the flow modification structure being positioned juxtaposed to the gas feed port, at least one flow modification structure And a cap including Comprising a sieve bed. (Item 12) The at least one flow modification structure comprises a baffle, the interface according to item 11. (Item 13) The at least one flow modification structure comprises ribs, the interface according to item 11. (Item 14) The at least one flow modification structure comprises a gap, the interface according to item 11. (Item 15) The at least one flow modification structure comprises first and second baffles and a gap therebetween, the interface according to item 11. (Item 16) The at least one flow modification structure comprises first and second rows of baffles, the interface according to item 11. (Item 17) The at least one flow modification structure comprises first, second, and third rows of baffles, the interface according to item 11. (Item 18) The at least one flow modification structure comprises first and second rows of baffles and a gap between the baffles of each row, the interface according to item 11. (Item 19) The at least one flow modification structure comprises a first baffle and a second baffle, the second baffle having a curved body, the interface according to item 11. (Item 20) An oxygen concentrator comprising: a pressure source; at least one sieve bed, a container for storing a separation medium, the container having a container wall; a cap having a body, the body including: at least one gas feed port; a chamber for receiving gas from the port; at least one flow modifying structure extending from the chamber wall into the chamber, wherein the flow modifying structure is positioned juxtaposed to the gas feed port, the at least one flow modifying structure; a cap including; at least one sieve bed having; a plurality of valves; a patient output; and an oxygen concentrator. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In the accompanying drawings, which are incorporated in and constitute a part of this specification, embodiments of the invention are illustrated, and together with the general description of the invention given above and the detailed description given below, serve to exemplify the principles of the invention.

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[0050] Unless otherwise indicated, each mechanical drawing is presented to scale. That is, the size, position, and location of the components illustrated in each drawing are shown to scale relative to each other, which may also include being shown enlarged to scale.

Best Mode for Carrying Out the Invention

[0051] Description As described herein, when one or more components are described or shown as being connected, integrated, attached, joined, mounted, or otherwise interconnected, such interconnection may be direct between the components or may be indirect, such as through the use of one or more intermediate components. Also, as described herein, references to members, components, or parts are not limited to a single structural member, component, element, or part and may include assemblies of components, members, elements, or parts.

[0052] Embodiments of the present invention provide gas separation systems and methods having, for example, efficient flow of working gas into and out of a sieve floor, reduced pressure loss and energy consumption, lower dynamic and static pressures on the sieve floor material, and an improved life of the sieve material by reducing the rate at which the sieve material mechanically and / or structurally fails. The efficient flow of the working gas also reduces the noise generated by the gas flow within the system. One In an embodiment, the gas separation system includes at least one sieve bed having a diffuser arranged to subdivide the flow in its cross-section into smaller flow channels, thereby reducing turbulent flow and energy losses. The gas flow is substantially straightened by the diffuser, and more energy is transmitted in the intended direction of the gas flow. The diffuser also has a low to medium solid area (e.g., low to medium solidity) in the cross-section and a high and / or maximum open area for flow, while also containing sieve material and providing appropriate mechanical properties for supporting the filter medium within the sieve bed.

[0053] Illustrated in FIG. 1 is one embodiment of a gas separation system 100 that can be an oxygen enrichment system. The system can be stationary, for example, for use in a hospital or a patient's home. The system can also be portable or mobile, for example, for use by a patient when away from home. The system can be configured in a manner that allows a patient to carry the system, for example, through a shoulder strap or through an arrangement where the system includes a handle and wheels. Other mobility configurations are also included.

[0054] Oxygen system 100 includes a housing 102, which may be in one or more compartments. The housing 102 includes, for example, a plurality of openings for the intake and discharge of various gases such as the intake of indoor air and the discharge of nitrogen and other gases. The oxygen system 100 generally intakes indoor air consisting mostly of oxygen and nitrogen and separates nitrogen from oxygen. Oxygen is stored in one or more internal or external storage or product tanks, and nitrogen is discharged back into the indoor air. For example, oxygen gas may be discharged to a patient through port 104, through tubing and a nasal cannula. Alternatively, oxygen gas may be discharged through an auxiliary port to an oxygen cylinder filling device such as HOMEFILL® manufactured by Invacare Corp. (Elyria, Ohio, USA), one embodiment of which is described in U.S. Patent No. 5,988,165 (incorporated by reference).

[0055] FIG. 2 illustrates one embodiment of an exemplary pneumatic block diagram of a gas concentration system using the pressure swing adsorption method (PSA). The system can include a plurality of gas separation sieve beds 206a and 206b, a plurality of valves 204a, 204b, 204c, and 204d, one or more product tanks 208a, 208b, and a conserving valve / device 218. In this embodiment, product tanks 208a, 208b are shown connected and thus they act as one product tank, but they may also be arranged to act as two product tanks. The system also includes a compressor / pump 203, one or more filters 201, and a muffler 202.

[0056] The sheave beds 206a and 206b are filled with a physical separation medium or material. The separation material selectively adsorbs one or more adsorbable components and allows one or more non-adsorbable components of the gaseous mixture to pass through. Generally, the physical separation material is a molecular sieve with uniform size and pores of essentially the same molecular dimensions. These pores selectively adsorb molecules according to molecular shape, polarity, saturation, and the like. In one embodiment, the physical separation medium is an aluminosilicate composition with pores of 4 - 5 ANG (angstrom). More specifically, the molecular sieve is in the sodium or calcium form of an aluminosilicate such as 5A zeolite. Alternatively, the aluminosilicate may have a higher silicon-to-aluminum ratio, larger pores, and an affinity for polar molecules, for example, 13x zeolite. Zeolites adsorb nitrogen, carbon monoxide, carbon dioxide, water vapor, and other significant components of air. Other types of separation media may also be used to adsorb nitrogen from ambient or indoor air. Also, more than two sheave beds can be used. In other embodiments, the sheave bed 206a and 206b can be structurally integrated with one or more product tanks 208a and 208b as described in U.S. Patent No. 8,668,767 (which is hereby fully incorporated by reference in its entirety for this and other features).

[0057] During operation, as shown by the solid lines in FIG. 2, during an exemplary filling cycle of the separation bed 206a, the pump / compressor 203 draws indoor air through the filter 201, through the valve 204d, and into the separation bed 206a, which, at its output, produces oxygen into the product tanks 208a, 208b through the valve 210a. The pump / compressor 203 supplies up to approximately 32 pounds per square inch of air to the sheave bed during the filling stage. Other operating pressure ranges include from about 15 to 32 pounds per square inch. The valves 210a and 210b may be check valves or any other similarly functioning valve that allows one-way flow.

[0058] While separation bed 206a is undergoing a filling cycle, separation bed 206b may undergo a purge cycle to discharge any nitrogen gas from a previous filling cycle. During the purge cycle, the previously pressurized separation bed 206b discharges nitrogen gas into the atmosphere through valve 204a and through muffler 202. Separation bed 206a is pressurized from its filling cycle. During the purge cycle, an amount of oxygen from separation bed 206a or product tanks 208a, 208b can be fed into separation bed 206b to preload or prefill separation bed 206b with oxygen, as controlled by optional bleed valve 212 and fixed orifice 214 shown in dashed lines in FIG. 2.

[0059] As shown by the dashed lines in FIG. 2, once separation bed 206a is filled and / or separation bed 206a is purged, control system 220 switches valves 204a, 204b, 204c, and 204d so that while separation bed 206b enters a filling cycle, separation bed 206a enters a purge cycle. In this state, pump 203 directs indoor air into separation bed 206b, which, at its output, produces oxygen into product tanks 208a, 208b through valve 210b. During the purge cycle, an amount of oxygen from separation bed 206b or product tanks 208a, 208b can be fed into separation bed 206a to preload or prefill separation bed 206a with oxygen flowing in the opposite direction compared to the previous cycle here. The illustrated system also includes exemplary pressure equalization valve 216, which equalizes the pressure in the two separation beds prior to a purge / fill cycle change. In particular, not all embodiments of a PSA system require a pressure equalization valve.

[0060] The pressure equalization valve 216 can enable more efficient generation of oxygen by equalizing the pressure between the outputs of the separation beds (e.g., 206a) near the end of its filling cycle and the separation beds (e.g., 206b) near the end of its purge cycle. For example, the pressure equalization valve 216 may be activated to equalize the pressure between the outputs of separation bed 206a and separation bed 206b near the end of each purge / filling cycle. U.S. Pat. Nos. 4,449,990 and 5,906,672 (which are hereby incorporated by reference in their entirety) further describe the operation of the pressure equalization valve. Thus, each separation bed 206a, 206b periodically undergoes alternating filling and purge cycles to generate oxygen, as controlled by the control system 220.

[0061] As shown in FIG. 2, an optional conserving valve / device 218 may be used to control the delivery of the product gas to the user 222. The conserving valve 218 may alternate between providing the enriched product gas from the product tanks 208a, 208b and venting to the room air. For example, the conserving valve 218 may be used to selectively provide various continuous or pulsed flows of the oxygen-enriched product gas at amounts and times determined by the control system 220. This time is typically based on sensing the inhalation by the user which is typically determined by sensing a decrease in pressure (or an increase in flow) proximate to the user's nose or mouth.

[0062] In this embodiment, the control system 220 may utilize various control schemes to optimize the generation and delivery of the enriched product gas, for example, by controlling the activation, level, and relative timing of the pressure source 203 and valves 204a, 204b, 204c, 204d, 216, and 212. This is accomplished by the use of one or more pressure sensors 224 and / or oxygen concentration sensors 226. In one embodiment, the pressure and oxygen sensors 224 and 226 monitor the pressure and oxygen concentration entering the product tanks 208A and 208(b). In other embodiments, the use of a timed cycle can be employed, where the cycle time is set at the factory or determined or optimized using a diagnostic process at system startup. In other embodiments, the cycle time can be determined from the flow settings and / or the sensed patient flow requirements.

[0063] FIG. 2 illustrates a pressure swing adsorption (PSA) cycle, although other gas concentration cycles, including vacuum swing adsorption (VSA), vacuum-pressure swing adsorption (VPSA), or other similar modes, may also be used. The particular gas concentration mode is not critical to the embodiments of the invention described herein, so long as they are capable of producing an enriched gas such as oxygen to the user. Examples of the above operating modes are disclosed, for example, in U.S. Pat. Nos. 9,266,053 and 9,120,050 (which are hereby incorporated by reference in their entirety).

[0064] Referring now to FIG. 3, an embodiment of a sieve bed arrangement 300 is shown. The sieve bed 300 includes, for example, a first gas input / output 302 for receiving air and exhausting adsorbed nitrogen gas. An optional headspace 304 can be provided. The sieve bed 300 further includes a spring 306, a perforated disk or diffuser 308, and one or more filter media 310. The spring 306 holds the sieve material 312 in a packed state together and resists mechanical movement of the sieve material 312 during the dynamic pressure used to fill and purge the sieve bed 300 during the gas separation process, biasing the perforated disk or diffuser 308 against the sieve material 312 (e.g., a granular separation or zeolite material as described above). The other end of the sieve material 312 is biased against one or more filter media 314 and a second perforated disk or diffuser 316. A second headspace 318 allows non-adsorbed gas (e.g., oxygen) to enter and leave the sieve bed via the input / output port 320. Although this embodiment has been described in detail, one or more components may be omitted or some components may be integrated. For example, one or more of the headspaces 304 and 318 can be substantially reduced or eliminated. Further, more than one diffuser 308 can be used. For example, two or more diffusers 308 can be used back-to-back or two or more diffusers 308 can be used in combination with one or more filter media 310 therebetween.

[0065] Figures 5A-5B illustrate another embodiment of the sieve bed 500. The sieve bed 500 includes many of the same functional components described in connection with the sieve bed 300 of FIG. 3, for example. The sieve bed 500 includes a retaining ring or clip 502 used to retain the input / output gas cap 504. Springs 506, retainers 508, diffusers 510, and filter media 512 and 514 are further provided. The springs 506 bias the retainers 508, diffusers 510, and filter media 512 and 514 against the granular sieve material 516 and keep them together packed within the sieve bed container wall, preventing or minimizing mechanical movement of the sieve bed material during the filling and purge cycles of the dynamic pressure used. A retaining ring 518 and a second diffuser 524 are located at the other end of the sieve material 516, together with one or more filter media 520 and 522. As described in connection with FIG. 3, more than one diffuser 510 can be used in any of the embodiments described herein. FIGS. 6A-6B illustrate various cross-sectional perspective views of the sieve bed 500, with its components assembled within the sieve bed container wall 600.

[0066] As described above in connection with FIG. 2, the system draws in ambient air through a compressor and moves it through a volume of material within a sieve bed that has the property of retaining nitrogen, and thus leaves an oxygen surplus at the output of the system. The sieve material used to adsorb nitrogen is typically granular in form and must be retained within the sieve bed in order for air to flow in, oxygen to flow out, and for the periodic purging of the sieve bed to exhaust the adsorbed nitrogen. As the gas flows in and out of the sieve bed, the granular sieve material must be retained and held in place to minimize its relative movement. For example, the introduction of air under pressure into the sieve bed creates a hammering effect on the sieve material, which can damage the granules and reduce them to dust, and its escape from the system must be minimized. Excessive loss of the sieve material is a failure mode in itself, and as more material is lost, the remaining material moves freely within the sieve bed, thereby accelerating relative movement and breakdown into dust.

[0067] A semi-permeable membrane or filter type medium (e.g., 512, 514, 520, and 522) may be used to hold the sieve material in place while allowing gas flow therethrough. These membranes or filters can be flexible structures, in which case they require mechanical support to retain the pressurized granular medium within an enclosed volume. To adequately support the filter medium, a portion of the filter area must be blocked from flow by a supporting mechanical structure such as a prior art disk as shown in FIGS. 4A and 4B. In many cases, the structure has holes that allow gas flow while providing mechanical support through the solid portion of the structure. However, the solid portion does not allow gas flow.

[0068] Regarding diffuser construction, there are limits to the open area of individual holes and the total open area relative to the sum of the areas of all holes. The individual hole area is limited by the mechanical properties of the filter medium, which can cause the filter medium to sag if the diameter between the geometric shapes of the holes (diameter in the case of round holes) is too large. The total open area is further limited by the stress and mechanical properties of the sieve material and the ability of the sieve bed vessel wall to withstand static and cyclic loads. The geometry of the individual holes and the pattern of the holes can also cause significant energy losses and noise in the system by causing pressure losses in the flowing gas. As will be further discussed herein, an appropriate diffuser geometry can reduce energy losses when appropriate features of the hole size, hole length in the direction of flow, pattern of holes and solid areas, hole orientation, and other hole characteristics that affect flow are provided. This can include the use of multiple diffusers as described above in relation to FIG. 3. In the case of multiple diffusers, each diffuser can have the same or different geometries to achieve the desired flow and structural properties. Also, other losses exist unless the flow into or out of the sieve bed during the exhaust cycle is uniform, which can be corrected or improved by the influence of flow modification features or geometries on the surface of the sieve bed by one or more diffusers and / or sieve caps / interfaces having flow modification structures.

[0069] Figures 7A - 7F illustrate various views of multiple embodiments of a diffuser 510 for a sieve bed The diffuser 510 has a low solidity, thereby providing a substantially large open area for flow. The diffuser 510 also supports the filter medium and has structural strength to transmit spring force or biasing to maintain the state where the sieve material is filled and withstands mechanical movement within the sieve bed container wall. The diffuser 510 includes a body 700 having a honeycomb wall structure in one embodiment. The body 700 can have any suitable size and shape, including, for example, the disk shape shown in the figure. In one example, the disk has a diameter of 2.44 inches and a height D2 of 0.5 inches. Other dimensions and shapes regarding the open area are also possible, including, for example, triangles, squares, rectangles, other polygons, circular shapes (see the body 800 in FIG. 8 having a circular wall 802 defining a circular open area 704), ellipses, etc.

[0070] As shown in the enlarged view of FIG. 7B, the wall 706 has a honeycomb (or hexagonal) arrangement enclosing the open space 704. The solidity (the ratio of solid to the open area) of the diffuser 510 can be from about 0.10% to 50%. For example, in one embodiment shown in FIGS. 7A-D, with a honeycomb cell size D1 equal to 0.125 inches, a wall 706 thickness equal to 0.001 inches, and a diffuser body diameter equal to 2.44 inches, a solidity of 2.46% is achieved. In another embodiment shown in FIG. 7E, with a honeycomb cell size D1 equal to 0.5 inches, a wall 706 thickness equal to 0.001 inches, and a diffuser body diameter equal to 2.44 inches, a solidity of 0.41% is achieved. In yet another embodiment shown in FIG. 7F, with a honeycomb cell size D1 equal to 1.0 inches, a wall 706 thickness equal to 0.001 inches, and a diffuser body diameter equal to 2.44 inches, a solidity of 0.17% is achieved. Ideally, it is highly desirable to maximize the open area of the diffuser, but an arrangement that improves / increases the open area compared to the prior art is also desirable and provides efficiency. That is, maximizing the open area is not necessary for efficiency to be achieved.

[0071] By varying the size of the subdivided channels and / or independently changing the length of the channels in the direction of flow, the flow characteristics of the diffuser flow can be modified with the benefits of lower energy loss, more uniform flow entering the sieve bed, lower peak velocities at or near the surface of the sieve material, lower bulk flow velocities at any part of the sieve bed, lower flow acceleration into the sieve bed, lower flow acceleration out of the sieve bed during the exhaust cycle, lower forces on the sieve material, and less impact on the sieve material from the dynamic pressure or from the lower peak-to-peak acceleration of the bidirectional flow. A uniform flow or uniform pressure of the flow entering the sieve bed reduces or eliminates flow within the sieve bed that is not parallel to the overall direction of flow through the sieve bed, which increases the distance the air must travel to pass through the sieve material and decreases the efficiency in time and oxygen generation of the sieve. Similarly, at the outlet, a non-uniform restriction to the outlet pressure converges or diverges the flow and makes it non-parallel to the overall direction of flow out of the sieve bed, thus lengthening the duration of the exhaust / purge cycle and decreasing the efficiency of the exhaust / purge cycle and the overall bidirectional (fill / purge) cycle.

[0072] Figures 9-12 illustrate various embodiments of the cross-sectional body profile of the diffuser 510. For example, FIG. 9 illustrates a body 900 having a first concave surface profile 902. FIG. 10 illustrates a body 1000 having first and second concave surface profiles 1002 and 1004. FIG. 11 illustrates a body 1100 having a first convex surface profile 1102. FIG. 12 illustrates a body 1200 having first and second convex surface profiles 1202 and 1204. The embodiments of FIGS. 11 and 12 provide certain advantages of additional structural strength in their central sections due to the greater height of the diffuser walls and their portions. This resists bending and other undesired mechanical deformations. Other cross-sectional body profiles include, for example, wavy or undulating profiles, triangles, sawteeth, etc. The vane can also be considered as a possibility. The diffuser body can be made from any suitable material. This includes, for example, metals and plastics. Suitable metals include aluminum and stainless steel. The diffuser body can also be formed via 3D printing techniques that allow for simple and complex space and wall arrangements, including those disclosed herein.

[0073] The height of the diffuser body (e.g., D2 in FIG. 7C) or the various heights of the body cross-sectional profiles shown in FIGS. 9 - 12 reduce the inefficiencies of the flow by straightening the inflow into and / or outflow from the sieve bed. They also reduce the turbulence in the flow through the geometry of the diffuser walls (e.g., honeycomb, circular, etc.) and via the number of walls or channels. They also orient the inward and outward flows in the overall direction of the sieve bed to reduce the tangential or axial outflow that would otherwise cause air molecules to travel a longer distance, cross into, and / or exit from the sieve bed. The height D2 or the height of the cross-sectional profile can be any height determined to improve the flow efficiency, including the various heights shown and described in relation to FIGS. 9 - 12.

[0074] The height of the diffuser body (e.g., D2 in FIG. 7C) or the various heights of the body cross-sectional profiles shown in FIGS. 9 - 12 also provide structural or retention components as described above. That is, the spring 506 biases or applies a force to the sieve material to keep it in a fixed state and prevent it from moving through the diffuser (see, e.g., FIGS. 6A - 6B). Ideally, the diffuser body is made from a material with appropriate shear, tensile, and repeated fatigue properties to provide the required mechanical support (e.g., to prevent sagging under load). Thus, an optimized diffuser body that maximizes or enlarges the cross-sectional area open to the flow while still providing adequate mechanical strength for the retention of the sieve filter media and sieve material is possible considering the properties of the diffuser body material and minimizing the interstitial volume of the diffuser body material.

[0075] Increasing or maximizing the open area of the diffuser body can, in one embodiment, be associated with the mechanical properties required for the retention function of the diffuser body. The diffuser body retention function is related to the ability of the diffuser body to properly support the filter medium and the sieve material in the packed state. In addition to potentially stronger body materials with higher shear, tensile, and repeated fatigue properties, diffusers with a very high percentage of open area for flow compared to the total available area, and thus a low solids ratio, use an optimal pore size, minimize the interstitial volume of the material by increasing the moment of inertia of the mechanical design in the direction of flow, and clog a large number of pores by minimizing the gap volume between the materials, for example, to avoid sagging under mechanical loads, based on the mechanical requirements of the filter medium.

[0076] The use of the diffuser 510 shown in FIGS. 7A - 7D indicates that the separation process can be performed more efficiently by reducing the peak velocity of the gas entering the sieve bed (i.e., near or at the surface of the sieve material) while still achieving conventional gas separation results. The conventional peak velocity of up to 168.6 inches per second is reduced to 70.1 inches per second, which is a reduction of approximately 60%. The reduction in the peak velocity of the gas entering the sieve bed leads to many practical advantages. For example, less energy is required to operate the gas separation process due to the lower peak flow rate. The lower peak flow rate also means that the compressor does not need to be overworked, thereby reducing component wear and extending the compressor life. Additionally, the reduced peak velocity reduces the pressure or mechanical forces within the sieve material and thus reduces dust generation and mechanical failures of the sieve bed material by reducing the relative movement of the sieve bed material. It also reduces the dynamic forces on the sieve bed surface, on the sieve filter, and / or on the sieve material, thereby reducing the mechanical degradation of the sieve bed material. Additionally, the reduced peak velocity reduces the noise caused by the airflow within the system.

[0077] Efficiency is also achieved by a diffuser space / channel having a height / length (e.g., D2 in FIG. 7C) that straightens the flow of the sieve material in and out. Straightening the flow also reduces inefficiencies by reducing the turbulent flow within the diffuser and / or caused by the diffuser at the surface of the sieve material. Straightening the flow also reduces tangential or crossflow that would otherwise travel a longer distance, cross into or out of the sieve bed, by orienting the inward and outward flow in the overall direction of the bed to direct the air molecules. The disclosed diffuser arrangement also provides mechanical support for any retention mechanism for the sieve material that must be within the flow path. As an overall result, the gas separation system has lower energy consumption, greater oxygen output or specific output (oxygen produced per unit of energy input), higher reliability defined by the life of the sieve bed against dust generation, and lower noise. All of the benefits and advantages can be achieved, but any one or more of them are sufficient to provide an improved gas separation process.

[0078] In another embodiment, a system and method are provided that have an indicator when a component is inspected or repaired. In one embodiment, the indicator provides a visual indication of whether the component has been tampered with in any manner. This allows the manufacturer to determine whether the component has been inspected, repaired, or tampered with outside of the manufacturer's domain. Unauthorized inspection or repair can lead to premature component wear and failure.

[0079] Illustrated in FIG. 13 is an embodiment of a system having anti-tampering features or arrangements. FIG. 13 shows an enlarged partial cross-sectional view of an upper portion of the sheave floor from FIGS. 6A-6B. The sheave floor includes anti-tampering features or arrangements that provide a visual indication as to whether, for example, the sheave floor has been opened to replace the sheave material. The sheave material 516 is a component that needs to be replaced over time. This is because the sheave material 516 deteriorates over time due to, for example, dust generation or mechanical degradation, moisture, saturation wear, etc. Typically, the sheave material 516 needs to be replaced approximately every 18 months. Unauthorized replacement of the sheave material 516 with materials not permitted by the manufacturer can cause early failure of the dust generation and other gas separation components. The arrangement shown in FIG. 13 provides a visual indication as to whether the sheave floor has been opened.

[0080] Still referring to FIG. 13, an anti-tampering cap 504 for the sheave floor is shown associated with a single sheave floor container 600, and in other embodiments, a common anti-tampering cap 504 (acting as a manifold) can be used with a sheave floor container assembly having more than one sheave floor container. In still other embodiments, the sheave floor container 600 may use more than one anti-tampering cap 504.

[0081] Still referring to FIG. 13, the anti-tampering cap 504 for the sheave floor includes a body 1300. The body 1300 includes one or more ribs 1302A-D (see also FIG. 14A). The ribs include recesses or spaces 1304A-D. The recesses are arranged to receive and secure a retaining ring or clip 502 that is designed to hold the cap 504 to the sheave floor container wall 600 along with the periphery 1308. The sheave floor container wall 600 also includes an annular recess 1310 for receiving and securing a portion of the retaining ring 502. The ribs 1302A-D are also arranged to contact or substantially contact the container wall 600 It includes an outer surface or wall having portions 1316A - D that can be engaged. Thus, the retention ring 502 cannot be removed unless one or more rib portions 1316A - D are tampered with (e.g., cut, damaged, broken, or otherwise modified) in such a way that allows the removal of the retention clip 502. Tampering with the rib portions 1316A - D provides a visual indication that the sheath floor is likely to have been opened through visible damage to them. Further, tampering with the rib portions 1316A - D will also likely result in visual damage to the sheath container wall 600 at those locations. Still further, damage to the rib portions 1316A - D and / or the sheath container wall 600 and their locations will likely result in irreparable damage to the cap 504 and / or the sheath floor container wall 600. The end result is to deter tampering or unauthorized inspection of the sheath floor as it is likely to be irreparably damaged.

[0082] Figures 14A - B illustrate perspective and side elevation views of an embodiment of the cap 504 shown in FIG. 13. As described above, the cap body 1300 includes four ribs 1302A - D, each rib including a recess or space (e.g., 1304A - D) for receiving and securing a portion of the retention ring 502. Each rib 1302A - D also includes one or more wall portions or surfaces (e.g., 1316A - D) that are arranged to contact or substantially contact a portion of the sheath floor container wall 600 at those locations. Contact with the sheath floor container wall 600 at those locations is not necessary as long as any gaps created are small enough to limit the removal of the retention ring 502. The body 1300 further includes spaced perimeters 516 and 1314 (along with perimeter 1308) for retaining a gasket or O - ring and creating an interference fit that secures the cap body 1300 to the sheath floor container wall 600. The perimeters 1308, 1312, 1314 are not necessary parts of the anti - tampering features but can be modified to be included as well.

[0083] In other embodiments, it should be noted that the cap body 1300 may include fewer than four ribs 1302A-D, and each rib need not have a wall and recess for securing the retaining ring 502. It is sufficient for at least one rib to contain these features. Further, the geometry of the ribs, walls, and recesses can be modified from what is shown in the embodiments herein as long as a portion for securing the retaining ring 502 is provided in the cap body 1300 such that it is not readily removable (e.g., removal without physical damage or modification to the cap body 1300 and / or the sheave floor container wall 600, such as without creating a visual indicator). For example, the cap body 1300 can include a protruding member or tab 1306 adjacent to the recess 1304B. The protruding tab 1306 can be a component of the rib 1302B or a separate component thereon by itself. One protruding tab 1306 is shown, but more than one can be provided as components of the ribs 1302A-D. In other embodiments, the ribs 1302A-D are excluded and, instead, a plurality of protruding tabs, such as tab 1306, can be used in the same location as the ribs 1302A-D or in more locations to achieve the same result. In other embodiments, a plurality of tabs, such as tab 1306, can be used in combination with one or more ribs. The number, geometry, and shape are not important as long as the protruding members (e.g., ribs, tabs, and combinations thereof) at least partially enclose the retaining ring in the manner described herein, deter tampering, and / or provide a tampering indicator.

[0084] Figures 15A-B illustrate other embodiments of a sheave cap having anti-tampering features. This includes a ribless sheave cap design. In one embodiment, the sheave cap body can include a swivel dome of various configurations. Figure 15A illustrates one embodiment of a ribless sheave cap body 1300. The body is swiveled horizontally (as opposed to having individual vertically disposed ribs, for example) and projects or extends from the body 1300 to the retaining ring ma or includes a cylindrical surface 1500 having an edge portion 1504 arranged in a manner similar to the wall portions 1316A-D of FIGS. 13-14B that contacts or substantially contacts the sheath container wall 600 for securing the retaining ring or clip 502. FIG. 15B shows another embodiment of the ribless sheath cap body 1300 having a smaller or less cylindrical surface 1502 as compared to that of FIG. 15A. The cylindrical surface 1502 is also arranged with an edge region 1504 for contacting or substantially contacting the sheath container wall 600 in a manner similar to the wall portions 1316A-D of FIGS. 13-14B for securing the retaining ring or clip 502. The remaining features of the sheath cap body are similar to those already described in FIGS. 13-14B. Thus, the ribless walls / surfaces 1500 and 1502 are in the same manner as the wall portions 1316A-D but secure the retaining ring / clip 502 along the outer periphery beyond that achievable by using the individual ribs 1302A-D. The attempted removal of the retaining ring or clip 502 from the embodiments of FIGS. 15A and 15B results in damage to the edge or outer peripheral portion 1504 that secures the retaining ring or clip 502, thereby providing an indication of tampering. Thus, the sheath cap bodies disclosed herein are not limited to anti-tampering features with ribs and include both ribbed and / or ribless arrangements.

[0085] FIGS. 16A-D illustrate another embodiment of a sheath floor cap 504 having anti-tampering features. In this embodiment, the cap 504 includes one or more structural portions that rupture or break in response to an attempted removal of the retaining ring or clip 502, thereby rendering the cap 504 no longer reusable. This is accomplished by creating one or more weakened portions in the body 1300.

[0086] In the illustrated embodiment, the body 1300 includes a dome portion 1600 that is arranged to partially or completely break in response to an attempted removal of the retention ring or clip 502. The partial or complete breakage or rupture, among other things, breaks the ability of the internal space 1604 to function properly at the required operating sieve bed pressure and effectively renders the gas separation system inoperative. Referring to FIGS. 16C and 16D, the body 1300 includes recesses or spaces 1304A-D for at least partially securing the retention ring or clip 502. The recesses or spaces 1304A-D are bounded on one side by the outer peripheral wall 1602 of the body 1300. As shown in FIG. 16C, the wall 1602 has a first wall thickness, where it bounds the recesses or spaces 1304A-D. As shown in FIG. 16D, when the outer peripheral wall 1602 does not bound the recesses or spaces 1304A-D, the wall 1602 has a second thickness that is less than the first thickness shown in FIG. 16C. The difference in thickness can be any difference that makes the wall 1602 more prone to rupture or breakage in response to an attempted removal of the retention ring or clip 502. In one embodiment, the difference in thickness can be from about 25% to 90%. The precise difference in thickness is not critical as long as the portion of the sieve bed cap ruptures or breaks in response to an attempted removal of the retention ring or clip 502.

[0087] In another embodiment, the lower dome outer peripheral wall 1606 adjacent to the wall 1602 can have portions of different thicknesses in the same manner as described for the wall 1602 to achieve the same rupture or breakage result. That is, the portion of the wall 1606 shown in FIG. 16C can have a first thickness that is greater than the portion of the wall 1606 shown in FIG. 16D. Thus, the smaller thickness of the portion of the wall 1606 shown in FIG. 16D is arranged to rupture or break in response to an attempted removal of the retention ring or clip 502. Other arrangements of the cap 504 having portions arranged to fracture, rupture, or break can also be used to prevent unauthorized access to the sieve bed and / or reuse of a tampered sieve bed and cap.

[0088] The cap 504 can be made of polycarbonate or other plastics and / or thermoplastic in one embodiment. The material composition can be of any composition that ruptures or breaks in response to a tried removal of the retaining ring or clip 502, thereby enabling a structural part that makes the cap 504 no longer reusable. This can further include metals, alloys, ceramics, and other moldable, printable, and / or machine - processable materials.

[0089] Another factor that can cause sieve - bed wear and tear, including dust generation and fluidization of the sieve - bed material, is the non - uniform flow distribution and velocity of the gas (e.g., air) entering the sieve - bed material. The air is typically input into the sieve - bed through a cap or other input interface. The internal - chamber geometry of the cap / interface can result in non - uniform flow distribution and / or regions of high flow - velocity concentration with respect to the gas entering the sieve - bed material. These undesirable effects can be addressed by using flow - modifying structures, partitions, and / or protrusions to obtain a more uniform and / or optimized flow distribution and flow velocity of the gas entering the sieve - bed material. Various embodiments of sieve - bed caps / interfaces for modifying the flow distribution and / or flow velocity of the gas entering the sieve - bed material are shown in FIGS. 17A - 27B.

[0090] Referring now to FIGS. 14A, 14B, and 17A-17B, an embodiment of a sheave floor cap / interface 504 having flow modification structures, partitions, and / or protrusions is shown. Referring now to the bottom view of FIG. 17A, the body 1300 includes an inner chamber geometry having a hemispherical or dome-shaped wall or surface 1700, first flow modification structures 1702 and 1704, second flow modification structures 1706 and 1708, and a third flow modification structure 1710. A first gap 1712 is located between the first flow modification structures 1702 and 1704. A second gap 1714 is located between the second flow modification structures 1706 and 1708. In this embodiment, the flow modification structures are generally arranged in three spaced-apart columns from a gas port 1716 that feeds gas into the chamber. The first flow modification structures 1702 and 1704 are juxtaposed proximate to the gas port 1716 by a first distance D1, which can be about 0.45 (FIG. 17A is shown enlarged to scale). The second flow modification structures 1706 and 1708 are spaced from the first flow modification structures 1702 and 1704 by a distance D2, which can be about 0.42 inches. The third flow modification structure 1710 is spaced from the second flow modification structures 1706 and 1708 by a distance D3, which can be about 0.33 inches. In other embodiments, these distances can be changed without substantially altering the flow modification results.

[0091] The flow modification structures 1702-1710 are, in one embodiment, baffles or ribs that deflect the gas flowing in from the port 1716. As shown in FIG. 17A, the first flow modification structures 1702 and 1704 and the third flow modification structure 1710 have a generally flat body with a rounded or curved end face. The second flow modification structures 1706 and 1708 have a curved body with a curved end face. The curved bodies of the structures 1706 and 1708 are shown to curve in a general direction toward the gas port 1716 in this embodiment. In other embodiments, the amount of flatness and curvature of any of these structures can vary from that shown without substantially affecting the flow modification results.

[0092] Referring now to FIG. 17B, a cross-sectional view of FIG. 17A is shown at a relative scale. The bodies of the flow modification structures 1702-1710 each extend downwardly from the wall 1700 a distance into the chamber. The internal chamber has a height H3 as shown, which can be about 1.2 inches. The first flow modification structures 1702 and 1704 extend downwardly to a height H1 as shown, which can be about 0.91 inches. The second and third flow modification structures 1706, 1708, and 1710 extend downwardly to a height H2 as shown, which can be about 0.71 inches. In other embodiments, these dimensions can be varied without substantially affecting the flow modification results FIG. 17C is a bottom perspective view further illustrating the size, location, and shape of the flow modification structures 1702-1710 and the gaps 1712 and 1714. FIG. 17D is a cross-sectional perspective view of the sheave floor cap, and FIG. 17E is an associated cross-sectional view of FIG. 17D showing the first flow modification structures 1702 and 1704 and the gap 1712. FIG. 17F is another cross-sectional perspective view, and FIG. 17G is an associated cross-sectional view of FIG. 17F showing the second flow modification structures 1706 and 1708 and the gap 1714. Also, FIG. 17H is another cross-sectional perspective view, and FIG. 17I is an associated cross-sectional view of FIG. 17H showing the third flow modification structure 1710.

[0093] Referring again to FIG. 17A here, gas is fed into the chamber from port 1716 and encounters the first flow modification structures 1702 and 1704 and the gap 1712. This provides a first flow modification to the gas, with some passing through the gap 1712 into the space 1718 and other portions being deflected into the spaces 1720 and 1722 where they encounter the domed surface 1700. The gas flow then encounters the second flow modification structures 1706 and 1708 and the gap 1714, where a smaller portion of the gas passes through the gap 1714 and other portions are directed into the spaces 1720 and 1722 and encounter the domed surface 1700. In the illustrated embodiment, the gap 1714 is smaller than the gap 1712, thereby allowing less gas to pass through it compared to the gap 1712. In other embodiments, the gap 1714 can be about 0.1 to 1.0 times the size of the gap 1712. In other embodiments, the gap 1712 can correspondingly be smaller than the gap 1714. The second flow modification structures 1706 and 1708, by their shape, deflect a portion of the gas inwardly into the gap 1714 and a portion of the gas outwardly towards the spaces 1720 and 1722. This provides a further or second flow modification to the gas flow. The gas flow then encounters the third flow modification structure 1710. This deflects the gas into the spaces 1726 and 1728 where it encounters the domed surface 1700. FIG. 18B, discussed below, illustrates these flow patterns through computational fluid dynamics simulations.

[0094] Thus, the gas flow can be incrementally modified through each row of structures or baffles to achieve the desired flow distribution and / or velocity of the gas entering the sieve bed material. This provides optimization of the flow to achieve a more uniform distribution and flow velocity as the gas enters the sieve material, thereby reducing wear and tear (e.g., dust generation, fluidization, etc.) of the sieve material.

[0095] Figures 18A - 18C illustrate the flow distribution and velocity generated by the structure, partition, and / or protrusion of the cap / interface of FIGS. 17A - 17I as modeled by computational fluid dynamics software by Ansys, Inc. FIG. 18A shows a cross - sectional view similar to FIG. 17B, with the calculated flow 1800 of the generated flow and their velocities resulting from the flow being guided within the cap / interface shown along the x and y - axis directions. FIG. 18B shows a bottom view similar to FIG. 17A, with the calculated flow 1800 of the generated flow and their velocities shown along the x and z - axis directions. In FIGS. 18A and 18B, the velocities are shown such that, with respect to the flow 1800, they go from higher to lower as the shading goes from light to dark.

[0096] FIG. 18C illustrates the calculated flow and / or velocity distribution resulting from the plane location shown in FIG. 18A, which is close to the surface of the sieve bed material and / or the diffuser (e.g., 510). Thus, FIG. 18C represents the calculated flow distribution and velocity on or near the surface of the sieve bed material. As shown, the flow distribution includes a relatively large substantially uniform distribution of the flow region 1802 that extends outward from the center. A second smaller region 1804 having an arc shape also exists with a substantially uniform flow distribution. FIGS. 18A and 18 B. Similarly, the velocities are shown such that they go from higher to lower as the shading goes from light to dark. Two exceptions are the small regions 1806 and 1808, where these dark regions represent velocities higher than the average flow velocity. Except for the very small regions 1806 and 1808, an optimized substantially uniform flow distribution of the gas is obtained, which represents about 70 - 80% (or more) of the area close to the surface of the sieve bed material. This uniformity makes the sieve bed more efficient by introducing the gas more uniformly into the sieve bed material, thereby limiting or eliminating pockets of the sieve material where the gas might not reach if it were unevenly distributed as it enters the sieve bed material.

[0097] For reference, FIGS. 18D and 18E illustrate the flow distribution and velocity of the cap / interface of FIGS. 17A-17I without any flow modification structures, partitions, and / or protrusions. As seen in FIG. 18D, the flow stream 1800 is not evenly distributed within the internal chamber of the cap. Also, as seen in FIG. 18E, the resulting flow distribution concentrates along a narrow arc 1810 along the internal chamber boundary wall opposite the gas port 1716. This non-uniform flow distribution generates undesirable higher flow velocities and / or required pressures, which cause sieve bed wear and tear, including dust generation and fluidization of the sieve material, wear of the filter medium, compressor wear (over time), etc.

[0098] FIGS. 19A and 19B illustrate another embodiment of the sieve bed cap / interface 504 having flow modification structures. The embodiments of FIGS. 19A and 19B are similar to those of FIGS. 17A-17I, except that the second flow modification structures 1900 and 1902 are not curved (as opposed to the second flow modification structures 1706 and 1708 of FIGS. 17A-17I, which are shown curved). As shown, the second flow modification structures 1900 and 1902 have a generally flat body with rounded or curved end faces. Other than this difference, the embodiments of FIGS. 17A-17I and FIGS. 19A-19B are similar (including the flow pattern (see FIG. 20B)), and corresponding descriptions are incorporated herein by reference.

[0099] Figures 20A-20C illustrate the flow distribution and velocity generated by the structure, partition, and / or protrusion of the cap / interface of FIGS. 19A-19B as modeled by computational fluid dynamics software by Ansys, Inc. Thus, the same analysis as shown and described in FIGS. 18A-18C was performed on the embodiment of FIGS. 19A-19B. FIG. 20A shows a cross-sectional view similar to FIG. 19B, with the calculated flow streams 2000 resulting from the flow diverted within the cap / interface and their velocities shown along the x and y axis directions. FIG. 20B shows a bottom view similar to FIG. 19A, with the resulting calculated flow streams 1800 and their velocities shown along the x and z axis directions. In FIGS. 20A and 20B, the velocities are shown such that they go from higher to lower as the shading goes from light to dark with respect to the flow stream 2000.

[0100] FIG. 20C illustrates the calculated flow and / or velocity distribution resulting at the planar location shown in FIG. 20A, in proximity to the surface of the sheave floor material and / or diffuser (e.g., 510). Thus, FIG. 20C represents the calculated flow distribution and velocity in the vicinity of the surface of the sheave floor material. As shown, the flow distribution includes a relatively large substantially uniform distribution of the flow region 2002 extending outward from the center. A second smaller region 2004 with a slightly disrupted arc shape also exists with a substantially uniform flow distribution. Similar to FIGS. 20A and 20B, the velocities are shown such that they go from higher to lower as the shading goes from light to dark. Two exceptions are the small regions 2006 and 2008, where these darker regions represent velocities higher than the average flow velocity. A very small region Except for 2006 and 2008, an optimized substantially uniform flow distribution of the gas representing about 70 - 80% (or more) of the area close to the surface of the sieve bed material is obtained. As explained above, this uniformity makes the sieve bed more efficient by introducing the gas more uniformly into the sieve bed material, thereby limiting or eliminating pockets of sieve material where the gas might not reach if it were unevenly distributed as it enters the sieve bed material.

[0101] In addition to the more uniform distribution that aids sieve bed efficiency, the flow velocities according to these embodiments are generally lower than those otherwise provided. The lower flow velocities reduce dust generation, fluidization, and other abrasion and tearing to the sieve bed and sieve bed material. This extends the life of the sieve bed, and thereby extends the life of the gas concentration system.

[0102] Figures 21A - 21D illustrate another embodiment of the sheave floor cap / interface 504 having a flow modification structure. This embodiment includes two columns of flow modification structures. The first column is the same as that of the embodiment of Figures 17A - 17I and includes the first flow modification structures 1702 and 1704 and the gap 1712. The second flow modification structure is different. These include the flow modification structures 2100 and 2102 and the gap 2104, which form a V - shape having curved legs (e.g., 2100 and 2102) and a small gap at the V - shaped apex (e.g., 2104). As described above, the flow modification structures 1702 and 1704 and the gap 1712 provide a first gas flow modification. The gas passing through the gap 1712 enters the space 2106 and encounters the second flow modification structures 2100 and 2102 and the gap 2104. A portion of the gas passes through the gap 2104, and another portion is deflected into the spaces 2108 and 2110 by the structures 2100 and 2102, where they encounter the dome - shaped surface 1700. The gas passing through the gap 2104 enters the space 2112, where it encounters the dome - shaped surface 1700. In the illustrated embodiment, the gap 2104 is smaller than the gap 1712, thereby allowing less gas to pass through it compared to the gap 1712. In other embodiments, the gap 2104 can be about 0.1 to 1.0 times the size of the gap 1712. In other embodiments, the gap 1712 can correspondingly be smaller than the gap 2104. Thus, the second flow modification structures 2100 and 2102 and the gap 2104 provide a second flow modification.

[0103] Figures 22A - 22D illustrate another embodiment of the sheave floor cap / interface 504 having a flow modification structure. This embodiment includes a flow modification structure 2200 having a V-shaped portion with stepped or undulating legs 2204 and 2206. The gas entering the internal chamber encounters the V-shaped portion, is split, and is deflected into spaces 2208 and 2210. However, since the legs 2204 and 2206 of the V-shaped portion have a stepped or undulating surface as shown, a small portion of the gas flow is deflected back against the newly emerging flow. The end result is to assist in distributing the flow more uniformly because not all of the flow is deflected into spaces 2208 and 2210, and not all of the flow is deflected into the side spaces 2208 and 2210. The portion of the flow deflected into spaces 2208 and 2210 also flows into space 2212 through the domed surface 1700 and the cylindrical portion 2202 of the flow modification structure 2200.

[0104] Figures 23A - 23D illustrate another embodiment of the sheave floor cap / interface 504 having a flow modification structure. This embodiment includes a flow modification structure 2300 that is essentially cylindrical and includes a first portion 2302 that is cylindrical and a second portion 2304 that is tapered or conical. The first portion 2302 provides a first gas flow modification by deflecting the gas around the structure 2300 into a space adjacent to the domed surface 1700. The second portion 2304 provides a second flow modification by deflecting the gas flow downwardly into the sheave floor material by virtue of its tapered or conical geometry. In other embodiments, the second portion 2304 may be more or less tapered or conical than shown.

[0105] Figures 24A - 24D illustrate another embodiment of the sheave floor cap / interface 504 having a flow modification structure. This embodiment includes a flow modification structure 2400 that includes a first portion 2402 that is essentially cylindrical, substantially cylindrical, and a second portion 2404 that is angled and may be curved (including concave and / or convex as shown). The first portion 2402 provides a first gas flow modification by deflecting the gas around the structure 2400 into the space adjacent to the dome - shaped surface 1700. The second portion 2404 provides a second flow modification by its angled nature, deflecting the gas flow downward into the sheave floor material in the region adjacent to the gas inlet port 1716. In other embodiments, the second portion 2404 may be more or less angled than that shown.

[0106] Figures 25A - 25D illustrate another embodiment of the sheave floor cap / interface 504 having a flow modification structure. This embodiment includes a flow modification structure 2500 that is located very near the gas inlet port 1716. The reason for being so close to the gas inlet port 1716 is to deflect the incoming gas flow into the flow of at least two smaller gas flows, thereby enabling the dome - shaped surface 1700 to distribute the flow more uniformly compared to when only a single gas flow encounters the dome - shaped surface 1700. The flow modification structure 2500 includes a substantially flat surface 2504 with curved end faces 2502 and 2506 on each of its sides. The curved end faces 2502 and 2506 provide a less turbulent and quieter deflection of the gas flow towards the dome - shaped surface 1700. In other embodiments, the end faces 2502 and 2506 need not be curved but can be substantially flat with respect to the surface 2504 and angled. As shown in Figure 25D, the flow modification structure 2500 can extend significantly downward into the internal chamber of the sheave floor cap / interface. In other embodiments, this can extend less than that shown, including, for example, only up to the outer periphery of the gas inlet port 1716 or slightly beyond it.

[0107] Figures 26A-26D illustrate another embodiment of the sheave floor cap / interface 504 having a cylindrical wall 2600, for example, instead of the domed surface 1700. In this embodiment, the side and upper portions of the cylindrical wall 2600 act as a flow modification structure and distribute the flow into two regions. The gas flow entering from port 1716 encounters the sidewall portion 2602, which divides the flow into upper and lower flow streams. The upper flow stream is then deflected downward by the upper surface 2604 and the side surface portion 2606 to form a second lower flow stream. The splitting of the main gas flow stream entering from the gas inlet port 1716 into two or more flow streams provides a more uniform flow distribution of the gas entering the sheave floor material. The surfaces 2608, 2610, 2612, and 2614 optionally expand the lower portion of the body 1300 in a stepped manner and provide a mounting base to the sheave floor container wall 600 (see FIG. 6).

[0108] Figures 26E-26F illustrate the flow distribution and velocities generated by the cap / interface of FIGS. 26A-26D as modeled by computational fluid dynamics software by Ansys, Inc. Accordingly, the same analysis as shown and described in FIGS. 18A-18C was performed on the embodiment of FIGS. 26A-26D. FIG. 26D shows a cross-sectional view similar to FIG. 19B, with the calculated flow streams 2614 and their velocities resulting from the flow being guided within the cap / interface shown along the x and y axis directions. In FIG. 26D, the velocities are shown as decreasing from higher to lower as the flow stream 2000 progresses from lighter to darker shades.

[0109] Figure 26F illustrates the calculated flow and / or velocity distribution resulting at the planar location shown in Figure 26E, proximate to the surface of the sheave floor material and / or diffuser (e.g., 510). Thus, Figure 26E represents the calculated flow distribution and velocity at the surface of the sheave floor material. As shown, the flow distribution includes a generally uniform distribution in the flow region 2616. A second region 2618 of uniform flow distribution also exists. Similar to Figure 26E, the velocity is shown to go from higher to lower as the shading goes from light to dark. Two exceptions are the small regions 2622 and 2624, which represent areas of higher concentration than the average flow velocity. Except for the very small regions 2622 and 2624, an optimized generally uniform flow distribution of the gas representing approximately 70 - 80% (or more) of the area proximate to the surface of the sheave floor material is obtained. As described above, this uniformity makes the sheave floor more efficient by introducing the gas more uniformly into the sheave floor material, thereby limiting or eliminating pockets of the sheave material where the gas might not reach if it were unevenly distributed as it enters the sheave floor material.

[0110] Figures 27A and 27B illustrate another embodiment of the sheave floor cap / interface 504 having a continuous flow modification structure 2700, for example, instead of discrete rows or columns of structures. Structure 2700 includes several portions including curved side portions 2712 and 2714 and a central portion 2706. The curved side portions 2712 and 2714 and the central portion 2706 extend into the internal chamber of the cap from the dome surface 1700 via curved surfaces 2702, 2704, and 2708, and surface 2710. Surface 2710 can be linear or curved (as shown via 2716) (including having multiple curves) and performs a first flow modification by splitting the gas flow entering from port 1716 into at least two flowing streams. The curved side portions 2712 and 2714 direct a portion of the gas flow back towards spaces 2718 and 2720 where the gas flow encounters the dome surface 1700 and is directed downwardly towards the sheave material, providing a second flow modification that operates similarly to the curved flow modification structures 1706 and 1708 (e.g., FIG. 17A). This redirection provides a flow distribution into the sheave floor from the region (e.g., spaces 2718 and 2720) that exceeds what would otherwise be provided, thereby generating a more uniform overall flow distribution of the gas entering the sheave material. This embodiment shows a single central portion 2706 extending into the internal chamber of the cap, but in other embodiments, the central portion 2706 may be divided into several portions that mimic, for example, the low modification structures of FIGS. 17A - 21D, such that these structures can extend from the dome surface 1700 by the curved surfaces and are interconnected by the curved surfaces while still maintaining the same general configuration as shown in these embodiments.

[0111] The final results of the foregoing embodiments are a more uniform flow distribution and a lower flow velocity compared to a sheave floor cap 504 that does not have any flow modification structure associated therewith. Additionally, the flow modification structures of the various embodiments shown and described herein can be further combined to create additional combinations of flow modification structures. Further, the sheave floor cap / interface embodiments shown and described can be used with or without a flow diffuser such as diffuser 510 disclosed herein. Still further, while the flow modification structures are shown as part of the sheave floor cap / interface as an example, these same structures can also be implemented as separate components, inserts, and / or adapters to be installed within an existing sheave floor cap / interface or separately mounted within the sheave floor assembly to function in conjunction with the sheave floor cap or interface. Even further, the sheave floor cap / interface can include both anti-tampering features and flow modification structures as disclosed herein.

[0112] The present invention is illustrated by the description of its embodiments, which have been described in considerable detail, but it is not the intention of the description to limit the scope of the disclosure to such detail or in any way. Additional advantages and modifications will readily occur to those skilled in the art. For example, the relative sizes, dimensions, and shapes of the components can be changed without significantly affecting their functionality. Accordingly, the present invention is not limited to the specific details, representative devices, and illustrative examples shown and described in its broader aspects. Thus, departures from such details can be made without departing from the spirit or scope of the general inventive concept.

Claims

1. A system for providing a concentrated gas, the system comprising: at least one sieve bed (500)(300); said at least one sieve bed (500)(300) comprising: a separation medium (516)(312) for adsorbing one or more components of a gas mixture; a biasing member (506)(306); at least one diffuser (510)(308) between said biasing member (506)(306) and said separation medium (516)(312); and a retainer (508) between said biasing member (506)(306) and said at least one diffuser (510)(308); wherein said retainer (508) transmits the force generated by said biasing member (506)(306) to said at least one diffuser (510)(308).

2. The system of claim 1, wherein said retainer (508) at least partially surrounds said at least one diffuser (510)(308).

3. The system of claim 1, wherein said at least one diffuser (510)(308) comprises an upper surface and a bottom surface, and said retainer (508) at least partially extends above said upper surface.

4. The system of claim 1, wherein said at least one diffuser (510)(308) comprises an upper surface and a bottom surface, and said retainer (508) at least partially extends around said upper surface.

5. The system of claim 3, wherein said retainer (508) at least partially extends around said upper surface.

6. The system of claim 1, wherein said at least one diffuser (510)(308) comprises an upper wall, a bottom wall, and side walls, and said retainer (508) at least partially extends below said side walls.

7. The system of claim 1, wherein said at least one diffuser (510)(308) comprises an upper wall, a bottom wall, and side walls, and said retainer (508) at least partially extends around the lower periphery of said side walls.

8. The system of claim 6, wherein said retainer (508) at least partially extends around the lower periphery of said side walls. **Claim 9**: The at least one sieve bed (500)(300) further comprises a container having an inner wall, and the retainer (508) is at least partially between the inner wall and the side wall of the at least one diffuser (510)(308). The system according to claim 1. **Claim 10**: The retainer (508) comprises a recess, and the recess receives at least a part of the biasing member (506)(306) therein. The system according to claim 1. **Claim 11**: The retainer (508) comprises a recess, and the recess receives at least a part of the at least one diffuser (510)(308) therein. The system according to claim 1. **Claim 12**: The retainer (508) comprises a first recess and a second recess. The first recess receives at least a part of the biasing member (506)(306) therein, and the second recess receives at least a part of the at least one diffuser (510)(308) therein. The system according to claim 1. **Claim 13**: The first recess and the second recess are arranged on opposite sides of each other. The system according to claim 12. **Claim 14**: The retainer (508) comprises a central opening and at least one surface extending at least partially into the central opening. The system according to claim 1. **Claim 15**: A sieve bed (500)(300), wherein the sieve bed (500)(300) comprises a separation material (516)(312) for adsorbing one or more components of a gas mixture, a biasing member (506)(306), at least one diffuser (510)(308) between the biasing member (506)(306) and the separation material (516)(312), and a retainer (508) between the biasing member (506)(306) and the at least one diffuser (510)(308), and the retainer (508) transmits the force generated by the biasing member (506)(306) to the at least one diffuser (510)(308), and the at least one diffuser (510)(308) transmits the force to the separation material (516)(312). The sieve bed (500)(300). **Claim 16**: The restraint (508) comprises a first part and a second part, the first part being between the biasing member (506)(306) and the at least one diffuser (510)(308), and the second part being between the at least one diffuser (510)(308) and the separation material (516)(312). The sheath floor (500)(300) according to claim 15. **Claim 17**: The restraint (508) at least partially surrounds a part of the at least one diffuser (510)(308). The sheath floor (500)(300) according to claim 15. **Claim 18**: The restraint (508) comprises a first recessed part and a second recessed part. The first recessed part receives at least a part of the biasing member (506)(306) therein, and the second recessed part receives at least a part of the at least one diffuser (510)(308) therein. The sheath floor (500)(300) according to claim 15. **Claim 19**: A sheath floor (500)(300), wherein the sheath floor (500)(300) means (516)(312) for separating one or more components of a gas mixture; means (510)(308) for reducing turbulence into the means (516)(312) for separation; means (506)(306) for generating a spring biasing force against the means (510)(308) for reducing turbulence; and means (508) for transmitting the spring biasing force from the means (510)(308) for reducing turbulence to the means (516)(312) for separation A sheath floor (500)(300) comprising. **Claim 20**: The sheath floor (500)(300) according to claim 19, further comprising means (508) for holding the means (506)(306) for generating the spring biasing force and the means (510)(308) for reducing turbulence.

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