Systems and methods for concentrating gases - Patents.com

Abstract

Systems and methods are provided that obtain 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, for example, contains a sieve material and includes a diffuser that has a low solid area in cross section and a maximum open area for flow while providing adequate mechanical properties to support the filter media. In another embodiment, a system and method is provided that has an indicator when a component has been inspected or repaired.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 052,694, filed July 16, 2020 (Attorney Docket No. 12873-07004), and No. 63 / 212,920, filed June 21, 2021 (Attorney Docket No. 12873-07156), entitled “System and Method for Concentrating Gas.”

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

[0003] Various applications exist for 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 flight personnel. 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 concentration of oxygen.

[0004] For example, several existing product gas or oxygen concentration systems and methods are disclosed in 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, which are commonly assigned to Invacare Corporation (Elyria, Ohio) and are hereby incorporated by reference in their entireties.

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

[0006] Gas enrichment systems typically generate dynamic flows and pressures within their working components as part of the separation and enrichment process. These flows and pressures are necessary, but also affect the mechanical wear and life of the system components. Generally, the higher the required flows and pressures in the system, the greater their impact on the mechanical wear and life of the system components. Also, the higher the required flows and pressures in 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 enrichment systems.

[0007] In another aspect, gas enrichment systems require inspection during their life. Various gas separation components need to be either replaced, repaired, or inspected. Manufacturers have a need to know when such components have been inspected outside the manufacturer's premises. What is desired is a system that also addresses this aspect of a gas separation or enrichment system. Summary of the Invention [Means for solving the problem]

[0008] A gas concentration system and method are provided. In one embodiment, a system and method are provided that obtains the same or better level of performance by using lower operating flow rates and pressures in the system. This extends the life of the system components and reduces energy consumption. In one embodiment, a gas separation (or sieve) bed is provided that is used to separate gaseous components, which has lower flow and pressure requirements compared to conventional beds. The sieve bed includes, for example, a diffuser that contains sieve material and has low solid area in cross section and maximum open area for flow while providing the right mechanical properties to support the filter media. 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 is provided that has an indicator when a component has been serviced or repaired. This provides an indication of whether the component has been tampered with in any way. This allows a manufacturer to determine if the component has been serviced, repaired, or tampered with outside the manufacturer's premises. Unauthorized service or repair can result in premature component wear and failure.

[0010] In yet another embodiment, systems and methods are disclosed that have a more uniform or optimized flow distribution and / or lower velocity of gas entering the sieve bed material. The sieve bed cap and / or gas input interface are provided with flow modifying structures, partitions, or protrusions in the flow chamber to distribute the flow more uniformly and reduce the velocity of the gas flow entering the sieve bed material. These structures, partitions, and / or protrusions direct the incoming gas flow into adjacent spaces in 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 the sieve bed efficiency by introducing the gas more uniformly into the sieve bed material, thereby limiting or eliminating pockets of sieve material that may not otherwise be reached by the gas when it is unevenly distributed as it enters the sieve bed material. The reduced gas flow velocity also reduces mechanical wear and tear on the sieve bed material, which causes dusting and fluidization of the material.

[0011] It is an object to provide more efficient gas separation systems and methods.

[0012] It is another object to provide a gas separation system and method having lower flow rates and pressures.

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

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

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

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

[0017] It is another object to provide a gas separation system and method having at least one tamper-resistant component.

[0018] It is another object to provide a gas separation system and method having at least one tamper-resistant sieve bed.

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

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

[0021] It is another object to provide a gas separation system and method that reduces the flow rate of gas into the sieve bed material, thereby reducing wear and tear (e.g., dusting, fluidization, etc.) on the sieve material.

[0022] These and other objects, features, and advantages will become apparent after review of the following description, drawings, and claims. The present specification also provides, for example, the following items: (Item 1) 1. A diffuser for a gas separation system, the diffuser comprising: A body having a height and an area, the area comprising a solid area and an open area. Equipped with A diffuser comprising a solid area to open area ratio of about 50% or less. (Item 2) Item 2. The diffuser of item 1, wherein the ratio of solid area to open area is about 0.10%. (Item 3) Item 2. The diffuser of item 1, wherein the ratio of solid area to open area is about 0.10% to 50%. (Item 4) Item 2. The diffuser of item 1, wherein the solid area to open area ratio is about 2.46%. (Item 5) Item 2. The diffuser of item 1, wherein the solid area to open area ratio is about 0.41%. (Item 6) Item 2. The diffuser of item 1, wherein the solid area to open area ratio is about 0.17%. (Item 7) Item 2. The diffuser of item 1, wherein the open area has at least one polygonal shape. (Item 8) Item 2. The diffuser of item 1, wherein the open area has at least one hexagonal shaped area. (Item 9) Item 2. The diffuser of item 1, wherein the open area has at least one circular shaped area. (Item 10) Item 2. The diffuser of item 1, wherein the body has a concave profile. (Item 11) Item 2. The diffuser of item 1, wherein the body has first and second concave profiles. (Item 12) Item 2. The diffuser of item 1, wherein the body has a convex profile. (Item 13) Item 2. The diffuser of item 1, wherein the body has first and second convex profiles. (Item 14) 1. A system for providing concentrated gas, comprising: At least one sieve bed, a separation medium for adsorbing one or more components of a gas mixture; at least one diffuser having a body, the body having a height and an area, the area comprising a solid area and an open area; At least one sieve bed having Equipped with The system comprises a ratio of solid area to open area of ​​about 50% or less. (Item 15) Item 15. The system of item 14, wherein the ratio of solid area to open area is about 0.10% to 50%. (Item 16) Item 15. The system of item 14, wherein the open area has at least one polygonal shape. (Item 17) Item 15. The diffuser of item 14, wherein the open area has at least one hexagonal shaped area. (Item 18) Item 15. The diffuser of item 14, wherein the open area has at least one circular shaped area. (Item 19) 1. A method for providing enriched gas, comprising: directing the gaseous mixture into a diffuser having a solid area and an open area, the ratio of solid area to open area being between about 0.10% and 50%; directing the gaseous mixture through the open area to a separation medium that adsorbs at least components of the gaseous mixture; A method comprising: (Item 20) 20. The method of claim 19, wherein directing the gaseous mixture through an open area comprises directing the gaseous mixture through an open area having a polygonal shape. [Brief description of the drawings]

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

[0024] [Figure 1] FIG. 1 illustrates one embodiment of a gas concentration system.

[0025] [Diagram 2] FIG. 2 is one embodiment of a pneumatic block diagram of a gas concentration system.

[0026] [Diagram 3] FIG. 3 is a block diagram of one embodiment of a gas separation or sieve bed.

[0027] [Figure 4] 4A-4B illustrate a prior art filter disk used in conjunction with a gas separation bed.

[0028] [Figure 5A] 5A-5B illustrate a perspective exploded view of one embodiment of a gas separation bed. [Figure 5B] 5A-5B illustrate a perspective exploded view of one embodiment of a gas separation bed.

[0029] [Figure 6A] 6A-6B are various cross-sectional views of the gas separation bed embodiment of FIGS. 5A-5B. [Figure 6B] 6A-6B are various cross-sectional views of the gas separation bed embodiment of FIGS. 5A-5B.

[0030] [Figure 7-1] 7A-7F illustrate various views of several embodiments of a diffuser having a honeycomb structure. [Figure 7-2] 7A-7F illustrate various views of several embodiments of a diffuser having a honeycomb structure.

[0031] [Figure 8] FIG. 8 illustrates a top view of a second embodiment of a diffuser having a cylindrical or straw-like structure.

[0032] [Figure 9] 9-12 illustrate side elevation views of various embodiments of diffusers having different cross-sectional geometries and profiles. [Figure 10] 9-12 illustrate side elevation views of various embodiments of diffusers having different cross-sectional geometries and profiles. [Figure 11] 9-12 illustrate side elevation views of various embodiments of diffusers having different cross-sectional geometries and profiles. [Figure 12] 9-12 illustrate side elevation views of various embodiments of diffusers having different cross-sectional geometries and profiles.

[0033] [Figure 13] FIG. 13 illustrates a partial cross-sectional view of one embodiment showing the anti-tamper features.

[0034] [Figure 14] 14A-B illustrate perspective and elevation views of one embodiment of a sieve floor cap that includes an anti-tamper feature.

[0035] [Figure 15] 15A-B illustrate a further embodiment of a sieve floor cap having an anti-tamper feature.

[0036] [Figure 16-1] 16A-16D illustrate yet another embodiment of a sieve floor cap having an anti-tamper feature. [Figure 16-2] 16A-16D illustrate yet another embodiment of a sieve floor cap having an anti-tamper feature.

[0037] [Figure 17-1] 17A-17I illustrate one embodiment of a sieve bed cap for generating a desired flow profile. [Figure 17-2] 17A-17I illustrate one embodiment of a sieve bed cap for generating a desired flow profile.

[0038] [Figure 18-1] 18A-18C illustrate various flow trajectories and distributions for the sieve bed cap embodiment of FIGS. 17A-17I.

[0039] [Figure 18-2] 18D-18E illustrate various flow trajectories and distributions for the sieve bed cap embodiment of FIGS. 17A-17I, although without any flow modifying structures present.

[0040] [Figure 19] 19A-19B illustrate another embodiment of a sieve bed cap for generating a desired flow profile.

[0041] [Figure 20] 20A-20C illustrate various flow trajectories and distributions for the sieve bed cap embodiment of FIGS. 19A-19C.

[0042] [Figure 21] 21A-21D illustrate various views of another embodiment of a sieve bed cap for generating a desired flow profile.

[0043] [Figure 22] 22A-22D illustrate various views of another embodiment of a sieve bed cap for generating a desired flow profile.

[0044] [Figure 23] 23A-23D illustrate various views of another embodiment of a sieve bed cap for generating a desired flow profile.

[0045] [Figure 24] 24A-24D illustrate various views of another embodiment of a sieve bed cap for generating a desired flow profile.

[0046] [Diagram 25] 25A-25D illustrate various views of another embodiment of a sieve bed cap for generating a desired flow profile.

[0047] [Figure 26-1] 26A-26D illustrate various views of another embodiment of a sieve bed cap for generating a desired flow profile.

[0048] [Figure 26-2] 26E-26F illustrate various flow trajectories and distributions for the sieve bed cap embodiment of FIGS. 26A-26D.

[0049] [Figure 27] 27A-27B illustrate various views of another embodiment of a sieve bed cap for generating a desired flow profile.

[0050] Unless otherwise indicated, each mechanical drawing is presented to scale, i.e., 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] explanation As described herein, when one or more components are described or shown as being connected, joined, affixed, coupled, attached, or otherwise interconnected, such interconnection may be direct, as between the components, or may be indirect, such as through the use of one or more intermediate components. Also, as described herein, reference to a member, component, or portion is not intended to be limited to a single structural member, component, element, or portion, but can include a collection of components, members, elements, or portions.

[0052] The present invention provides a gas separation system and method having, for example, efficient flow of working gas into and out of the sieve bed, reduced pressure loss and energy consumption, lower dynamic and static pressures on the sieve bed material, and improved life of the sieve material by reducing the rate at which the sieve material mechanically and / or structurally fails. Efficient flow of working gas also reduces noise generated by the gas flow in the system. In one 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 turbulence and energy loss. The gas flow is substantially straightened by the diffuser, and more energy is transferred in the intended direction of the gas flow. The diffuser also has a low solid area (e.g., low solidity) in cross section and a high and / or maximum open area for flow, while also containing the sieve material and providing the right mechanical properties to support the filter media in the sieve bed.

[0053] Illustrated in FIG. 1 is one embodiment of a gas separation system 100, which may be an oxygen concentrator system. The system may be stationary, such as for use in a hospital or in the patient's home. The system may also be ambulatory or mobile, such as for use by the patient when the patient is away from home. The system may be configured in a manner that allows the patient to carry the system, such as through an over-the-shoulder strap or an arrangement whereby the system includes a handle and wheels. Other mobile configurations are also included.

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

[0055] 2 illustrates one embodiment of an exemplary pneumatic block diagram for a gas concentration system using pressure swing adsorption (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 conserva valve / device 218. In this embodiment, the product tanks 208a, 208b are shown connected, so they act as one product tank, but 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 sieve beds 206a and 206b are packed 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 pores of uniform size and essentially identical 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 alumina silicate composition with pores of 4-5 ANG. (Angstroms). More specifically, the molecular sieve is a sodium or calcium form of alumina silicate, such as 5A type zeolite. Alternatively, the alumina silicate may have a higher silicon to aluminum ratio, larger pores, and an affinity for polar molecules, e.g., 13x type 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 room air. Also, more than two sieve beds can be used. In other embodiments, the sieve beds 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 incorporated by reference in its entirety for this and other features.

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

[0058] While separation bed 206a is undergoing a fill cycle, separation bed 206b may undergo a purge cycle to vent any nitrogen gas from the previous fill cycle. During the purge cycle, previously pressurized separation bed 206b vents nitrogen gas through valve 204a and through muffler 202 to the atmosphere. Separation bed 206a is pressurized from its fill cycle. During the purge cycle, an amount of oxygen from separation bed 206a or product tanks 208a, 208b can be pumped into separation bed 206b to preload or precharge 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 separated bed 206a is purged, control system 220 switches valves 204a, 204b, 204c, and 204d so that separation bed 206b enters a fill cycle while separation bed 206a enters a purge cycle. In this state, pump 203 directs room air into separation bed 206b, which produces oxygen at its output through valve 210b into product tanks 208a, 208b. During the purge cycle, a certain amount of oxygen from separation bed 206b or product tanks 208a, 208b can be pumped into separation bed 206a to preload or precharge separation bed 206a with oxygen now flowing in the opposite direction compared to the previous cycle. The illustrated system also includes an exemplary pressure equalization valve 216, which equalizes the pressure in the two separation beds prior to the purge / fill cycle change. Notably, 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 pressure between the output of a separation bed (e.g., 206a) near the end of its fill cycle and the output of a separation bed (e.g., 206b) near the end of its purge cycle. For example, the pressure equalization valve 216 may be activated to equalize pressure between the output of separation bed 206a and separation bed 206b near the end of each purge / fill cycle. U.S. Patent Nos. 4,449,990 and 5,906,672 (incorporated by reference herein in their entireties) further describe the operation of the pressure equalization valve. In this manner, each separation bed 206a, 206b is periodically subjected to alternating fill and purge cycles as controlled by the control system 220 to generate oxygen.

[0061] 2, an optional conserver valve / device 218 may be used to control the delivery of product gas to the user 222. The conserver valve 218 may switch between providing concentrated product gas from the product tanks 208a, 208b and venting to room air. For example, the conserver valve 218 may be used to selectively provide various continuous or pulsed flows of oxygen-enriched product gas in amounts and for times determined by the control system 220. The times are typically based on sensing an inhale by the user, which is typically determined by sensing a drop in pressure or (increased flow) adjacent 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 concentrated product gas, for example, by controlling the activation, levels, and relative timing of the pressure source 203 and valves 204a, 204b, 204c, 204d, 216, and 212. This is accomplished through 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 timed cycles can be employed, with cycle times set at the factory or determined or optimized using a diagnostic process at system start-up. In other embodiments, cycle times can be determined from flow settings and / or sensed patient flow demand.

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

[0064] Referring now to FIG. 3, one embodiment of a sieve bed arrangement 300 is shown. The sieve bed 300 includes a first gas input / output 302, for example, to receive air and exhaust adsorbed nitrogen gas. An optional head space 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 urges the perforated disk or diffuser 308 against the sieve material 312 (e.g., granular separation or zeolite material as described above) to keep the sieve material 312 packed together and resist mechanical movement of the sieve material 312 during dynamic pressures used to fill and purge the sieve bed 300 during the gas separation process. The other end of the sieve material 312 is urged against one or more filter media 314 and a second perforated disk or diffuser 316. The 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 headspaces 304 and 318 may be substantially reduced or eliminated. Additionally, more than one diffuser 308 may be used. For example, two or more diffusers 308 may be used back-to-back or two or more diffusers 308 may be used with one or more filter media 310 therebetween.

[0065] 5A-5B illustrate another embodiment of a sieve bed 500. The sieve bed 500 includes many of the same functional components described in connection with, for example, the sieve bed 300 of FIG. 3. The sieve bed 500 includes a retaining ring or clip 502 that is used to retain an input / output gas cap 504. A spring 506, a retainer 508, a diffuser 510, and filter media 512 and 514 are further provided. The spring 506 biases the retainer 508, the diffuser 510, and the filter media 512 and 514 against the granular sieve material 516, keeping it packed together within the sieve bed vessel wall and preventing or minimizing mechanical movement of the sieve bed material during the dynamic pressures used in the fill and purge cycles of the separation process. A retaining ring 518 and a second diffuser 524 are located at the other end of the sieve material 516 along with one or more filter media 520 and 522. As described in connection with Figure 3, more than one diffuser 510 can be used in any of the embodiments described herein. Figures 6A-6B illustrate various cross-sectional perspective views of sieve bed 500, the components of which are assembled within sieve bed vessel 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 in a sieve bed that has the property of retaining nitrogen, thus leaving a surplus of oxygen at the output of the system. The sieve material used to adsorb the nitrogen is typically granular in form and must be retained within the sieve bed to allow air to flow in, oxygen to flow out, and periodic scrubbing of the sieve bed to vent the adsorbed nitrogen. As gas flows in and out of the sieve bed, the granular sieve material must be retained and held in order to minimize its relative motion. 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, the escape of which from the system must be minimized. Excessive loss of sieve material is a failure mode in itself; as more material is lost, the remaining material is free to move within the sieve bed, thereby accelerating the relative motion and decomposition into dust.

[0067] Semi-permeable membranes or filter type media (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 may be flexible structures in which case they require mechanical support to keep the pressurized granular media from moving in a confined volume. To adequately support the filter media, a portion of the filter area must be blocked from flow by a supporting mechanical structure such as the prior art disks shown in Figures 4A and 4B. Often the structure has holes that allow gas flow while also providing mechanical support through the solid portions of the structure. However, the solid portions do not allow gas flow.

[0068] With respect to the diffuser structure, there are limitations on the open area of ​​each individual hole and the total open area of ​​the sum of the areas of all holes. The individual hole area is limited by the mechanical properties of the filter media, which can cause the filter media to sag if the span (diameter in round holes) of the hole geometry 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 individual hole geometry and hole pattern also contribute significantly to the energy loss and noise of the system by contributing to pressure loss of the flowing gas. As will be further discussed herein, a suitable diffuser geometry can reduce energy loss if appropriate characteristics of hole size, hole length in the direction of flow, hole and solid area pattern, hole orientation, and other hole features that affect flow are provided. This can include the use of multiple diffusers as described above in connection with FIG. 3. In the case of multiple diffusers, each diffuser can have the same or different geometry to obtain the desired flow and structural properties. Also, unless the flow into or out of the sieve bed during the evacuation cycle is uniform, other losses exist that can be corrected or ameliorated by the effect of flow modifying features or geometries at the face of the sieve bed by one or more diffusers and / or sieve caps / interfaces having flow modifying structures.

[0069] 7A-7F illustrate various views of multiple embodiments of a diffuser 510 for a sieve bed. The diffuser 510 has low solidity, thereby providing a substantially large open area for flow. The diffuser 510 also has structural strength to support the filter media and transmit a spring force or bias to keep the sieve material packed and resistant to mechanical movement within the sieve bed container wall. The diffuser 510 includes a body 700, which in one embodiment has a honeycomb wall structure. The body 700 can have any suitable size and shape, including, for example, the disk shape shown in the figures. In one example, the disk has a diameter of 2.44 inches and a height D2 of 0.5 inches. Other dimensions and shapes for the open area are also possible, including, for example, triangular, square, rectangular, other polygonal, circular (see, for example, body 800 in FIG. 8 having a circular shaped wall 802 defining a circular open area 704), elliptical, etc.

[0070] As shown in the enlarged view of FIG. 7B, the walls 706 have a honeycomb (or hexagonal) arrangement that encloses the open space 704. The solidity (ratio of solid to open area) of the diffuser 510 can be 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 and 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 obtained. In another embodiment shown in FIG. 7E, with a honeycomb cell size D1 equal to 0.5 inches and 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 obtained. In yet another embodiment shown in Figure 7F, with honeycomb cell size D1 equal to 1.0 inch and wall 706 thickness equal to 0.001 inch, and diffuser body diameter equal to 2.44 inch, a solidity of 0.17% is obtained. Ideally, maximizing the open area of ​​the diffuser is highly desirable, however, arrangements that improve / increase the open area over the prior art are also desirable and provide efficiency. That is, maximizing the open area is not necessary for efficiency to be realized.

[0071] By varying the size of the subdivided channels and / or independently varying 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 losses, more uniform flow entering the sieve bed, lower peak velocities at or near the face of the sieve material, lower bulk flow velocities in any portion of the sieve bed, lower flow acceleration into the sieve bed, lower flow acceleration out of the sieve bed during the evacuation cycle, lower forces on the sieve material, less impact on the sieve material from dynamic pressure or from lower peak-to-peak acceleration of bidirectional flow. Uniform flow or uniform pressure of flow entering the sieve bed reduces or eliminates flows within the sieve bed that are not parallel to the overall direction of flow through the sieve bed, which increases the distance the air must travel to make its way through the sieve material, reducing the time and efficiency of the sieve in producing oxygen. Similarly, at the outlet, uneven restriction to the outlet pressure will cause the flow to converge or diverge, non-parallel to the overall direction of flow out of the sieve bed, thus extending the duration of the vent / purge cycle and reducing the efficiency of the vent / purge cycle and the overall bidirectional (fill / purge) cycle.

[0072] 9-12 illustrate various embodiments of cross-sectional body profiles 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 longer height of the diffuser walls and portions thereof. This resists bending and other undesirable mechanical deformations. Other cross-sectional body profiles are also possible, including, for example, wavy or undulating profiles, triangular, sawtooth, etc. The diffuser body can be made of 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, allowing 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 flow inefficiencies by straightening the inflow and / or outflow to the sieve bed. They also reduce turbulence in the flow through the geometry of the diffuser walls (e.g., honeycomb, circular, etc.) and through the number of walls or channels. They also direct the inward and outward flow in the general direction of the sieve bed to reduce tangential or off-axis flows that would travel longer distances and direct air molecules to traverse into and / or out of the sieve bed. The height D2 or cross-sectional profile height can be any height determined to improve flow efficiency, including the various heights shown and described in connection with 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 a structural or retention component, as explained above. That is, the spring 506 applies a bias or force to the sieve material to keep it attached and not move through the diffuser (see, e.g., FIGS. 6A-6B). Ideally, the diffuser body is made from a material with the right shear, tensile, and cyclic fatigue properties to provide the required mechanical support (e.g., to prevent sagging under load). Thus, an optimized diffuser body is possible that enlarges or maximizes the cross-sectional area open to flow while still providing the right mechanical strength for retention of the sieve filter media and sieve material, while taking into account the properties of the diffuser body material and minimizing the void volume of the diffuser body material.

[0075] Enlarging or maximizing the diffuser body open area can be associated in one embodiment 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 media and sieve material in a filled state. In addition to potentially stronger body materials with higher shear, tensile, and cyclic fatigue properties, diffusers with a very high percentage of open area for flow compared to the total available area, and therefore a low solidity ratio, can be created by filling a large number of holes by using optimal hole sizes based on the mechanical needs of the filter media (e.g., to avoid sagging under mechanical load) and minimizing the void volume of the material by increasing the moment of inertia of the mechanical design in the direction of flow.

[0076] The use of the diffuser 510 shown in Figures 7A-7D shows 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 face of the sieve material) while still obtaining conventional gas separation results. The conventional peak velocity of up to 168.6 in / sec is reduced to 70.1 in / sec, which is about a 60% reduction. 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 compressor life. Furthermore, the reduced peak velocity reduces the pressure or mechanical forces within the sieve material, thus reducing dusting and mechanical failure of the sieve material by reducing the relative movement of the sieve bed material. This also reduces dynamic forces against the sieve bed faces, against the sieve filters, and / or against the sieve material, thereby reducing mechanical degradation of the sieve bed material. Furthermore, the reduced peak velocities also reduce noise caused by airflow within the system.

[0077] Efficiency is also obtained by the diffuser space / channel having a height / length (e.g., D2 in FIG. 7C) that straightens the flow in and out of the sieve material. Straightening the flow also reduces inefficiencies by reducing turbulence caused by the diffuser within the diffuser and / or at the face of the sieve material. Straightening the flow also orients the inward and outward flow in the general direction of the bed to reduce tangential or off-axis flows that would travel longer distances and direct air molecules to cross to enter or exit the sieve bed. The disclosed diffuser array also provides mechanical support for any retention mechanism for the sieve material that must be in the flow path. The overall result is a gas separation system with lower energy consumption, greater oxygen output or specific power (oxygen produced per unit of energy input), higher reliability as defined by the life of the sieve bed against dusting, and lower noise. All of the benefits and advantages can be obtained, but any one or more will be sufficient to provide an improved gas separation process.

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

[0079] Illustrated in FIG. 13 is one embodiment of a system having an anti-tamper feature or arrangement. FIG. 13 shows an enlarged partial cross-sectional view of the top portion of the sieve bed from FIG. 6A-6B. The sieve bed includes an anti-tamper feature or arrangement that provides a visual indication of whether the sieve bed has been opened, for example, to replace the sieve material. The sieve material 516 is a component that needs to be replaced over time. This is because the sieve material 516 deteriorates over time, for example, due to dusting or mechanical deterioration, moisture, saturation wear, etc. Typically, the sieve material 516 needs to be replaced about every 18 months. Unauthorized replacement of the sieve material 516 with a material not authorized by the manufacturer can cause dusting and premature failure of other gas separation components. The arrangement shown in FIG. 13 provides a visual indication of whether the sieve bed has been opened.

[0080] 13 illustrates an example where one tamper-evident cap 504 is associated with a single sieve bed vessel 600, while in other embodiments a common tamper-evident cap 504 (acting similarly to a manifold) may be used with a sieve bed vessel assembly having more than one sieve bed vessel. In yet other embodiments, a sieve bed vessel 600 may use more than one tamper-evident cap 504.

[0081] Still referring to FIG. 13, the sieve bed tamper proof cap 504 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, along with a peripheral edge 1308, are arranged to receive and secure a retaining ring or clip 502 designed to retain the cap 504 to the sieve bed vessel wall 600. The sieve bed vessel wall 600 also includes an annular recess 1310 for receiving and securing a portion of the retaining ring 502. The ribs 1302A-D also include outer surfaces or walls having portions 1316A-D arranged to contact or nearly contact the vessel wall 600. In this manner, the retaining ring 502 cannot be removed unless one or more of the rib sections 1316A-D are tampered with (e.g., cut, damaged, destroyed, or otherwise modified) to allow the retaining clip 502 to be removed. Tampering with the rib sections 1316A-D provides a visual indication that the sieve bed has likely been opened through visible damage thereto. Furthermore, tampering with the rib sections 1316A-D would also likely result in visual damage to the sieve vessel wall 600 at those locations. Still further, damage to the rib sections 1316A-D and / or the sieve vessel wall 600 and at those locations would likely result in irreparable damage to the cap 504 and / or the sieve bed vessel wall 600. The end result is to discourage tampering or unauthorized inspection of the sieve bed, as this would likely be irreparably damaged.

[0082] 14A-B illustrate perspective and side elevation views of an embodiment of the cap 504 shown in FIG. 13. As explained above, the cap body 1300 includes four ribs 1302A-D, each 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 nearly contact a portion of the sieve bed vessel wall 600 at those locations. Contact with the sieve bed vessel wall 600 at those locations is not necessary as long as any gaps created are small enough to limit removal of the retention ring 502. Body 1300 further includes spaced apart perimeter edges 516 and 1314 (along with perimeter edge 1308) for retaining a gasket or O-ring and creating an interference fit that retains cap body 1300 to sieve bed vessel wall 600. Perimeter edges 1308, 1312, 1314 are not a required part of the tamper-evident feature, but can be modified to be included as well.

[0083] It should be noted that in other embodiments, the cap body 1300 may include fewer than four ribs 1302A-D, and each rib need not have walls and recesses for securing the retention ring 502. It is sufficient that at least one rib contains these features. Furthermore, the geometry of the ribs, walls, and recesses can be modified from that shown in the embodiments herein, so long as portions are provided in the cap body 1300 for securing the retention ring 502 such that they are not easily removed (e.g., by physical damage or modification to the cap body 1300 and / or the sieve bed vessel wall 600, e.g., removal without creating a visual indicator). For example, the cap body 1300 can include a protruding member or tab 1306 adjacent the recess 1304B. The protruding tab 1306 can be a component of the rib 1302B or a separate component thereon of its own. Although one protruding tab 1306 is shown, more than one can be provided as a component of ribs 1302A-D. In still other embodiments, ribs 1302A-D can be eliminated and instead multiple protruding tabs such as tab 1306 can be used in the same location as ribs 1302A-D or in more locations to accomplish the same result. In still other embodiments, multiple tabs such as tab 1306 can be used in conjunction with one or more ribs. The number, geometry, and shape are not important so long as the protruding members (e.g., ribs, tabs, and combinations thereof) at least partially encapsulate the retention ring in the manner described herein, discourage tampering, and / or provide a tamper indicator.

[0084] 15A-B illustrate other embodiments of sieve caps with anti-tamper features. This includes a ribless sieve cap design. In one embodiment, the sieve cap body can include a pivoted dome of various configurations. FIG. 15A illustrates one embodiment of a ribless sieve cap body 1300. The body includes a cylindrical surface 1500 that is pivoted horizontally (e.g., as opposed to having individual vertically disposed ribs) and that protrudes or extends from the body 1300 and is arranged with edge portions 1504 in a manner similar to the wall portions 1316A-D of FIGS. 13-14B that contact or nearly contact the sieve vessel wall 600 to secure the retaining ring or clip 502. FIG. 15B illustrates another embodiment of a ribless sieve cap body 1300 with fewer or smaller cylindrical surfaces 1502 compared to those of FIG. 15A. The cylindrical surface 1502 is also arranged with an edge region 1504 to contact or nearly contact the sieve vessel wall 600 in a manner similar to the wall portions 1316A-D of Figures 13-14B for securing the retention ring or clip 502. The remaining features of the sieve cap body are similar to those already described in Figures 13-14B. Thus, the ribbed walls / surfaces 1500 and 1502 secure the retention ring / clip 502 in the same manner as the wall portions 1316A-D, but along a greater circumference than would be possible by using individual ribs 1302A-D. Attempted removal of the retention ring or clip 502 from the embodiment of Figures 15A and 15B would result in damage to the edge or perimeter portion 1504 to which the retention ring or clip 502 is secured, thereby providing a tamper indication. Thus, the sieve cap bodies disclosed herein are not limited to ribbed anti-tamper features, but include both ribbed and / or non-ribbed arrangements.

[0085] 16A-D illustrate another embodiment of a sheave floor cap 504 having an anti-tamper feature. In this embodiment, the cap 504 includes one or more structural portions that rupture or break in response to 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 embodiment shown, the body 1300 includes a dome portion 1600 that is arranged to rupture partially or completely in response to an attempted removal of the retaining ring or clip 502. A partial or complete rupture or bursting would, among other things, defeat the ability of the interior space 1604 to function properly at the required operational sieve bed pressure, effectively disabling the gas separation system. With reference to Figures 16C and 16D, the body 1300 includes recesses or spaces 1304A-D for at least partially securing the retaining ring or clip 502. The recesses or spaces 1304A-D are bounded on one side by a perimeter wall 1602 of the body 1300. As shown in Figure 16C, the wall 1602 has a first wall thickness, where it bounds the recesses or spaces 1304A-D. As shown in FIG. 16D, where the perimeter 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 thickness difference can be any difference that makes the wall 1602 more susceptible to rupture or break in response to attempted removal of the retaining ring or clip 502. In one embodiment, the thickness difference can be about 25% to 90%. The exact thickness difference is not critical as long as a portion of the sheave floor cap ruptures or breaks in response to attempted removal of the retaining ring or clip 502.

[0087] In another embodiment, the lower dome perimeter wall 1606 adjacent to the wall 1602 can have portions of different thickness in the same manner as described with respect to 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. In this manner, the lesser thickness of the portion of the wall 1606 shown in FIG. 16D is arranged to rupture or break in response to attempted removal of the retaining ring or clip 502. Other arrangements of the cap 504 having portions arranged to rupture, rupture, or break can also be used to prevent unauthorized access to the sieve bed and / or reuse of tampered sieve beds and caps.

[0088] The cap 504, in one embodiment, can be made from polycarbonate or other plastics and / or thermoplastics. The material composition can be any composition that allows for a structural portion to burst or break upon attempted removal of the retention ring or clip 502, thereby rendering the cap 504 no longer reusable. This can further include metals, alloys, ceramics, and other moldable, printable, and / or machinable materials.

[0089] Another factor that can cause sieve bed wear and tear, including dusting and fluidization of the sieve bed material, is non-uniform flow distribution and velocity of gas (e.g., air) entering the sieve bed material. Air is typically entered 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 concentrated areas of high flow velocity for 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 Figures 17A-27B.

[0090] 14A, 14B, and 17A-17B, one embodiment of a sieve bed 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 rows from a gas port 1716 that delivers gas into the chamber. The first flow modifying structures 1702 and 1704 are juxtaposed proximate the gas port 1716 by a first distance D1, which may be about 0.45 inches (FIG. 17A is shown to scale). The second flow modifying structures 1706 and 1708 are spaced apart from the first flow modifying structures 1702 and 1704 by a distance D2, which may be about 0.42 inches. The third flow modifying structure 1710 is spaced apart from the second flow modifying structures 1706 and 1708 by a distance D3, which may be about 0.33 inches. In other embodiments, these distances can be varied without substantially altering the flow modification results.

[0091] The flow modifying structures 1702-1710, in one embodiment, are baffles or ribs that deflect the gas entering from the port 1716. As shown in FIG. 17A, the first flow modifying structures 1702 and 1704 and the third flow modifying structure 1710 have generally flat bodies with rounded or curved ends. The second flow modifying structures 1706 and 1708 have curved bodies with curved ends. The curved bodies of the structures 1706 and 1708 are shown in this embodiment as curved in a general direction toward the gas port 1716. 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, the cross-sectional view of FIG. 17A is shown to relative scale. The bodies of the flow modifying structures 1702-1710 each extend a distance downward into the chamber from the wall 1700. The interior chamber has a height H3 as shown, which may be about 1.2 inches. The first flow modifying structures 1702 and 1704 extend downward to a height H1 as shown, which may be about 0.91 inches. The second and third flow modifying structures 1706, 1708, and 1710 extend downward to a height H2 as shown, which may 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 modifying structures 1702-1710 and the gaps 1712 and 1714. Figure 17D is a cross-sectional perspective view of the sieve bed cap and Figure 17E is an associated cross-sectional view of Figure 17D showing first flow modification structures 1702 and 1704 and gap 1712. Figure 17F is another cross-sectional perspective view and Figure 17G is an associated cross-sectional view of Figure 17F showing second flow modification structures 1706 and 1708 and gap 1714. And Figure 17H ​​is another cross-sectional perspective view and Figure 171 is an associated cross-sectional view of Figure 17H ​​showing third flow modification structure 1710.

[0093] 17A , gas is fed into the chamber from port 1716 and encounters first flow modifying structures 1702 and 1704 and gap 1712. This provides a first flow modification to the gas, with some passing through gap 1712 into space 1718 and other portions being deflected into spaces 1720 and 1722 where they encounter dome-shaped surface 1700. The gas flow then encounters second flow modifying structures 1706 and 1708 and gap 1714, where a smaller portion of the gas passes through gap 1714 and other portions are directed into spaces 1720 and 1722 where they encounter dome-shaped surface 1700. In the embodiment shown, gap 1714 is smaller than gap 1712, thereby allowing less gas to pass therethrough compared to gap 1712. In other embodiments, gap 1714 may be about 0.1 to 1.0 times the size of gap 1712. In other embodiments, gap 1712 may be correspondingly smaller than gap 1714. Second flow modifying structures 1706 and 1708, by their geometry, deflect a portion of the gas inwardly into gap 1714 and a portion of the gas outwardly toward spaces 1720 and 1722. This provides a further, or second, flow modification to the gas flow. The gas flow then encounters third flow modifying structure 1710, which deflects the gas into spaces 1726 and 1728 where it encounters dome-shaped 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 obtain a desired flow distribution and / or velocity of the gas entering the sieve bed material. This provides flow optimization to obtain a more uniform distribution and flow velocity as the gas enters the sieve material, thereby reducing wear and tear (e.g., dusting, fluidization, etc.) on the sieve material.

[0095] 18A-18C illustrate the flow distributions and velocities generated by the cap / interface structures, partitions, and / or protrusions 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 resulting calculated flow streams 1800 induced within the cap / interface and their velocities shown along the x and y axis directions. FIG. 18B shows a bottom view similar to FIG. 17A, with the resulting calculated flow streams 1800 and their velocities shown along the x and z axis directions. In FIGS. 18A and 18B, velocities are shown going from higher to lower for the flow streams 1800 as they go from light to dark shading.

[0096] FIG. 18C illustrates the resulting calculated flow and / or velocity distribution at the planar location shown in FIG. 18A proximate the surface of the sieve bed material and / or diffuser (e.g., 510). Thus, FIG. 18C represents the calculated flow distribution and velocities at or near the surface of the sieve bed material. As shown, the flow distribution includes a relatively large, generally uniform distribution of flow regions 1802 extending outward from the center. A second, smaller region 1804 having an arc shape is also present with a generally uniform flow distribution. As in FIGS. 18A and 18B, the velocities are shown going from higher to lower as the shading progresses from light to dark. The two exceptions are small regions 1806 and 1808, which represent higher than average flow velocities. An optimized, generally uniform flow distribution of gas is obtained, representing approximately 70-80% (or more) of the area adjacent the face of the sieve bed material, except for very small areas 1806 and 1808. 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 that the gas might not otherwise reach when the gas is unevenly distributed as it enters the sieve bed material.

[0097] For reference, Figures 18D and 18E illustrate the flow distribution and velocities of the cap / interface of Figures 17A-17I, but without any flow modifying structures, partitions, and / or protrusions. As seen in Figure 18D, the flow stream 1800 is not uniformly distributed within the cap's interior chamber. Also, as seen in Figure 18E, the resulting flow distribution is concentrated along a narrow arc 1810 along the interior chamber boundary wall opposite the gas port 1716. This uneven flow distribution creates undesirably higher flow velocities and / or required pressures, which can cause sieve bed wear and tear, including dusting and fluidization of the sieve material, wear of the filter media, compressor wear (over time), etc.

[0098] 19A and 19B illustrate another embodiment of a sieve bed cap / interface 504 having flow modification structures. The embodiment of FIG. 19A and 19B is similar to that of FIG. 17A-17I, except that the second flow modification structures 1900 and 1902 are not curved (versus the second flow modification structures 1706 and 1708 of FIG. 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 FIG. 17A-17I and FIG. 19A-19B are similar (including the flow patterns (see FIG. 20B)) and the corresponding descriptions are incorporated herein by reference.

[0099] 20A-20C illustrate the flow distributions and velocities generated by the cap / interface structures, partitions, and / or protrusions of FIGS. 19A-19B as modeled by computational fluid dynamics software by Ansys, Inc. Thus, the same analysis 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 resulting calculated flow streams 2000 guided 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, velocities are shown going from higher to lower for the flow streams 2000 as they go from light to dark shading.

[0100] FIG. 20C illustrates the resulting calculated flow and / or velocity distribution at the planar location shown in FIG. 20A proximate the surface of the sieve bed material and / or diffuser (e.g., 510). FIG. 20C thus represents the calculated flow distribution and velocities proximate the surface of the sieve bed material. As shown, the flow distribution includes a relatively large, generally uniform distribution of flow regions 2002 extending outward from the center. A second, smaller region 2004 with a slightly disturbed arc shape is also present with a generally uniform flow distribution. As in FIGS. 20A and 20B, the velocities are shown going from higher to lower as the shading progresses from light to dark. The two exceptions are small regions 2006 and 2008, which represent higher than average flow velocities. Except for very small areas 2006 and 2008, an optimized, generally uniform flow distribution of gas is obtained, representing approximately 70-80% (or more) of the area adjacent to the face of the sieve bed material. 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 that the gas might not otherwise reach when the gas is unevenly distributed as it enters the sieve bed material.

[0101] In addition to a more uniform distribution, which aids in sieve bed efficiency, the fluidization rates according to these embodiments are generally lower than would otherwise be provided. The lower fluidization rates reduce dusting, fluidization, and other wear and tear on the sieve bed and the sieve bed material. This extends the life of the sieve bed, and thereby the life of the gas concentration system.

[0102] 21A-21D illustrate another embodiment of a sieve bed cap / interface 504 with flow modification structures. This embodiment includes two rows of flow modification structures. The first row is identical to that of the embodiment of FIGS. 17A-17I and includes first flow modification structures 1702 and 1704 and gap 1712. The second flow modification structures are different. They include flow modification structures 2100 and 2102 and gap 2104, which form a V-shape with curved legs (e.g., 2100 and 2102) and a small gap at the apex of the V-shape (e.g., 2104). As explained above, the flow modification structures 1702 and 1704 and gap 1712 provide a first gas flow modification. Gas passing through gap 1712 enters space 2106 and encounters second flow modifying structures 2100 and 2102 and gap 2104. A portion of the gas passes through gap 2104 and another portion is deflected by structures 2100 and 2102 into spaces 2108 and 2110 where they encounter dome-shaped surface 1700. Gas passing through gap 2104 enters space 2112 where it encounters dome-shaped surface 1700. In the embodiment shown, gap 2104 is smaller than gap 1712, thereby allowing less gas to pass therethrough as compared to gap 1712. In other embodiments, gap 2104 may be about 0.1 to 1.0 times the size of gap 1712. In other embodiments, gap 1712 may be correspondingly smaller than gap 2104. Thus, the second flow modifying structures 2100 and 2102 and the gap 2104 provide a second flow modification.

[0103] 22A-22D illustrate another embodiment of the sieve bed cap / interface 504 with a flow modifying structure. This embodiment includes a flow modifying structure 2200 having a V-shaped portion with stepped or undulating legs 2204 and 2206. Gas entering the inner chamber encounters the V-shaped portion, is split, and is deflected into spaces 2208 and 2210. However, because 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 emerging flow. The end result is that some of the gas flow is not deflected into spaces 2208 and 2210, helping to distribute the flow more evenly since not all of the flow is deflected into the side spaces 2208 and 2210. The portion of the flow that is deflected into spaces 2208 and 2210 also flows into space 2212 via the domed surface 1700 and the cylindrical portion 2202 of the flow modifying structure 2200 .

[0104] 23A-23D illustrate another embodiment of a sieve bed 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 gas around the structure 2300 into the space adjacent to the dome-shaped surface 1700. The second portion 2304 provides a second flow modification by deflecting the gas flow downward into the sieve bed material by its tapered or conical geometry. In other embodiments, the second portion 2304 may be more or less tapered or conical than shown.

[0105] 24A-24D illustrate another embodiment of a sieve bed cap / interface 504 having a flow modification structure. This embodiment includes a flow modification structure 2400 including a first portion 2402 that is essentially cylindrical and generally cylindrical, and a second portion 2404 that is beveled and may be curved (including concave and / or convex as shown). The first portion 2402 provides a first gas flow modification by deflecting 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 deflecting gas flow downward into the sieve bed material in the area adjacent to the gas entry port 1716 due to its bevel. In other embodiments, the second portion 2404 may be beveled more or less than that shown.

[0106] 25A-25D illustrate another embodiment of the sieve bed cap / interface 504 having a flow modifying structure. This embodiment includes a flow modifying structure 2500 located in close proximity to the gas entry port 1716. The reason for such close proximity to the gas entry port 1716 is to deflect the incoming gas stream into at least two smaller gas streams, thereby allowing the domed surface 1700 to distribute the flow more evenly compared to if only a single gas stream encountered the domed surface 1700. The flow modifying structure 2500 includes a generally flat surface 2504 with curved end faces 2502 and 2506 on its sides, respectively. The curved end faces 2502 and 2506 provide a less turbulent and less noisy deflection of the gas stream into the domed surface 1700. In other embodiments, the end faces 2502 and 2506 do not have to be curved, but can be generally flat and angled relative to the surface 2504. 25D, the flow modifying structure 2500 can extend significantly down into the interior chamber of the sieve bed cap / interface. In other embodiments, it can extend less than shown, including, for example, only to the periphery of the gas entry port 1716 or slightly beyond.

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

[0108] Figures 26E-26F illustrate the flow distribution and velocities generated by the cap / interface of Figures 26A-26D as modeled by computational fluid dynamics software by Ansys, Inc. Thus, the same analysis shown and described in Figures 18A-18C was performed on the embodiment of Figures 26A-26D. Figure 26D shows a cross-sectional view similar to Figure 19B, where the resulting calculated flow streams 2614 induced within the cap / interface and their velocities are shown along the x and y axis directions. In Figure 26D, velocities are shown going from higher to lower as the shading progresses from light to dark for the flow stream 2000.

[0109] FIG. 26F illustrates the resulting calculated flow and / or velocity distribution at the planar location shown in FIG. 26E proximate the surface of the sieve bed material and / or diffuser (e.g., 510). FIG. 26E thus represents the calculated flow distribution and velocities at the surface of the sieve bed material. As shown, the flow distribution includes a substantially uniform distribution of flow regions 2616. A second region 2618 of uniform flow distribution is also present. As in FIG. 26E, the velocities are shown going from higher to lower as the shading progresses from light to dark. The two exceptions are small regions 2622 and 2624, which represent higher than average flow velocities. With the exception of the very small regions 2622 and 2624, an optimized substantially uniform flow distribution of gas is obtained, representing approximately 70-80% (or more) of the area proximate the surface of the sieve bed material. 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 that the gas might not otherwise reach when the gas is unevenly distributed as it enters the sieve bed material.

[0110] 27A and 27B illustrate another embodiment of the sieve bed cap / interface 504 having a continuous flow modifying 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. Curved side portions 2712 and 2714 and central portion 2706 extend from dome surface 1700 into the interior chamber of the cap via curved surfaces 2702, 2704, and 2708, and surface 2710. Surface 2710 may 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 flow streams. The curved side portions 2712 and 2714 act similarly to the curved flow modifying structures 1706 and 1708 (e.g., FIG. 17A ) by directing a portion of the gas flow back toward the spaces 2718 and 2720 where the gas flow encounters the dome surface 1700 and provides a second flow modification that is directed downward toward the sieve material. This redirection provides a greater distribution of flow from this region (e.g., spaces 2718 and 2720) into the sieve bed than would otherwise be provided, thereby generating a more uniform overall flow distribution of the gas entering the sieve material. While this embodiment shows a single central portion 2706 that extends into the internal chamber of the cap, 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, whereby these structures can extend from the dome surface 1700 by curved surfaces and are interconnected by curved surfaces while still maintaining the same general configuration as shown in these embodiments.

[0111] The end result of the foregoing embodiments is a more uniform flow distribution and lower flow velocities compared to a sieve bed cap 504 that does not have any flow modification structures associated therewith. Additionally, the flow modification structures of the various embodiments shown and described herein can be further combined to create additive combinations of flow modification structures. Furthermore, the sieve bed cap / interface embodiments shown and described can be used with or without a flow diffuser, such as the diffuser 510 disclosed herein. Still further, while the flow modification structures have been shown as part of the sieve bed cap / interface as an example, these same structures can also be implemented as separate components, inserters, and / or adapters to be installed within an existing sieve bed cap / interface or separately mounted within a sieve bed assembly to function in conjunction with the sieve bed cap or interface. Still further, the sieve bed cap / interface can include both anti-tamper features and flow modification structures as disclosed herein.

[0112] The present invention has been illustrated by the description of its embodiments, and although the embodiments have been described in considerable detail, it is not the intention of the description to restrict or in any way limit the scope of the present disclosure to such details. 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. Thus, the present invention in its broader aspects is not limited to the specific details, representative devices, and illustrative examples shown and described. Thus, departures from such details can be made without departing from the spirit or scope of the general inventive concept.

Claims

1. 1. A diffuser for a gas separation system, the diffuser comprising: A body comprising a wall structure having a wall, the wall having a wall height and a wall thickness, the body having an area perpendicular to the wall, the area comprising a solid area occupied by the wall and an open area bounded by the wall. Equipped with The ratio of solid area to open area is 50% or less; the body further comprises a mechanical strength configured to resist deformation of the body due to a biasing force against the solid area and further configured to transmit the biasing force through the solid area to a sheave material; the body further comprising a peak gas flow velocity reduction of 60%, the peak gas flow velocity comprising a velocity of gas flowing into the sieve material; a solid area to open area ratio of 50% or less further comprising a solid area void volume configured to support the filter media without the filter media sagging into the open area under mechanical load.

2. 2. The diffuser of claim 1, wherein the solid area to open area ratio is 0.10%.

3. The diffuser of claim 1 , wherein the ratio of solid area to open area is between 0.10% and 50%.

4. 10. The diffuser of claim 1, wherein the solid area to open area ratio is 2.46%.

5. 10. The diffuser of claim 1, wherein the solid area to open area ratio is 0.41%.

6. 10. The diffuser of claim 1, wherein the solid area to open area ratio is 0.17%.

7. The diffuser of claim 1 , wherein the open area has at least one polygonal shape.

8. The diffuser of claim 1 , wherein the open area comprises at least one hexagonal shaped area.

9. The diffuser of claim 1 , wherein the open area comprises at least one circular shaped area.

10. The diffuser of claim 1 , wherein the body has a concave profile.

11. The diffuser of claim 1 , wherein the body has first and second concave profiles.

12. The diffuser of claim 1 , wherein the body has a convex profile.

13. The diffuser of claim 1 , wherein the body has first and second convex profiles.

14. 1. A system for providing concentrated gas, comprising: At least one sieve bed, a separation medium for adsorbing one or more components of a mixture of gases; At least one diffuser according to claim 1; At least one sieve bed having A system comprising:

15. 15. The system of claim 14, wherein the ratio of solid area to open area is between 0.10% and 50%.

16. The system of claim 14 , wherein the open area has at least one polygonal shape.

17. The diffuser of claim 14 , wherein the open area comprises at least one hexagonal shaped area.

18. The diffuser of claim 14 , wherein the open area comprises at least one circular shaped area.

19. 1. A method for providing enriched gas, comprising: Directing a gaseous mixture into the diffuser of claim 1; directing the gaseous mixture through the open area to a separation medium that adsorbs at least components of the gaseous mixture; A method comprising:

20. 20. The method of claim 19, wherein directing the gaseous mixture through an open area comprises directing the gaseous mixture through an open area having a polygonal shape.

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