Rotary valve with adjustable sealing pressure and apparatus comprising such valve

Abstract

The rotary valve includes a housing and an end flange. The end flange includes a pressure port and a through bore having first and second open ends and a threaded section between the ends. A rotor is rotatably mounted in the housing and includes a contact surface. A stator is slidably mounted between the rotor and the end flange. The stator includes a first side facing a contact surface of the rotor, and an opposite second side including a spring seat. A spring is received in the spring seat and in the through hole on the flange. A spring tension adjuster threadingly couples the threaded section in the through hole and presses the spring toward the stator. The spring tension adjuster is configured to adjust the tension of the spring compressed between the stator and the end flange.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit and priority of U.S. Provisional Patent Application No. 63 / 415,870, filed on October 13, 2022, the entire content of which is incorporated herein by reference in its entirety. Technical field

[0003] The present disclosure generally relates to rotary valves with adjustable sealing pressure, and particularly to rotary valves with spring - loaded pressure and sealing mechanisms for pressure swing adsorption applications, as well as systems and devices incorporating such valves. Background art

[0004] Pressure - balanced rotary valves are useful in pressure swing adsorption (PSA) applications and systems. PSA has been used in various gas separation and purification applications, such as the separation or purification of biogas, gas - field gas, syngas, waste hydrogen streams, etc.

[0005] Typical rotary valves have a stator and a rotor that can rotate relative to the stator about a rotational axis and press against the stator. Each of the stator and the rotor has ports thereon that can be aligned or offset depending on the relative rotational position between the rotor and the stator. When the rotor rotates, the stator and the rotor remain in sliding and sealing contact under an axially applied pressure that biases the rotor and the stator towards each other. A biasing mechanism, such as a spring acting on both the stator and the rotor in some conventional rotary valves, is used to adjust or balance such axial pressure.

[0006] For example, U.S. Patent No. 6,063,161 to Keefer et al. discloses an example PSA system with a multi - port rotary valve, where the rotary valve is used to control the volumetric rate of gas flowing to and from an adsorbent bed during various steps of a PSA process.

[0007] U.S. Patent No. 8,272,401 to McLean also discloses a compact pressure - balanced rotary valve for a pressure - varying device that includes a variable - loading piston and a fixed - loading spring.

[0008] Additional rotary valves and their use in PSA systems are disclosed in, for example, U.S. Patent Nos. 38493, 4272265, 4406675, 4452612, 4469494, 4758253, 5112367, 5133784, 5248325, 5256174, 5268021, and 5366541.

[0009] However, conventional rotary valves such as those disclosed in US8,272,401 will still leak after being used for a period of time and will require maintenance or replacement from time to time. The maintenance and replacement of conventional rotary valves in a PSA system in turn require system downtime and costs associated with parts, labor, and other operating expenses.

[0010] Accordingly, there is a need to improve existing rotary valves and provide rotary valves that are easier to maintain and do not require frequent replacement. It is also desirable to improve existing rotary valves and provide rotary valves that are more convenient to use, install, operate, or maintain. SUMMARY OF THE INVENTION

[0011] According to one aspect of the present disclosure, there is provided a rotary valve comprising: a valve housing including a cylindrical passage and an end flange, the end flange including a pressure port and a through-hole having a first open end and a second open end and a threaded section between the first end and the second end; a rotor rotatably mounted in the cylindrical passage of the valve housing and capable of rotating about a rotation axis, the rotor including a contact surface generally perpendicular to the rotation axis; a stator slidably mounted inside the valve housing between the rotor and the end flange, the stator including a first side facing the contact surface of the rotor and a second side opposite the first side, the second side of the stator including a spring seat; a spring including a first end and a second end, the first end of the spring being received in the spring seat of the stator, the second end of the spring being received through the first open end of the through-hole in the end flange; a spring tension adjuster threadedly coupled to the threaded section in the through-hole of the end flange and pressing the spring toward the stator, the stator in turn being pressed toward the rotor by the spring, the spring tension adjuster being configured to be rotatable through the second open end of the flange to change the axial position of the spring tension adjuster so as to adjust the tension of the spring compressed between the stator and the end flange.

[0012] As described herein, it is convenient to install, operate, and maintain the rotary valve because the sealing pressure can be conveniently adjusted through the opening in the end flange without the need to stop using the valve and disassemble the valve itself.

[0013] In various embodiments, one or more of the following features may also be provided in the rotary valves described herein. For example, the stator may include pressure ports. Each of the flange and the stator may include a plurality of pressure ports, and the rotary valve may include a plurality of pressure ports for biasing the stator toward the rotor. Each of the rotor and the stator may include a plurality of fluid ports. The rotary valve may include a plurality of springs and a plurality of corresponding spring tension adjusters. Each of the springs may be positioned adjacent to one of the plurality of fluid ports and may be independently compressed by a corresponding spring tension adjuster. The spring tension adjuster may include a threaded stud. The spring tension adjuster may include an externally threaded tube or sleeve. The rotary valve may include a seal compressed between the rotor and the stator. The spring tension adjuster may include stainless steel. The rotary valve may include a removable cap covering the second open end of the through hole.

[0014] In another aspect, a rotary valve is provided that includes: a valve housing that includes a cylindrical channel and an end flange, the inner side of the end flange including a spring pocket having an adjustable cavity length that can be adjusted through an opening at the outer side of the end flange; a rotor rotatably mounted in the cylindrical channel of the valve housing and capable of rotating about a rotation axis, the rotor including a contact surface generally perpendicular to the rotation axis; a stator slidably mounted inside the valve housing between the rotor and the end flange, the stator including a first side adjacent to the contact surface of the rotor and a second side opposite the first side; and a spring received in the spring pocket and compressed between the end flange and the second side of the stator to bias the stator toward the rotor, wherein the tension in the spring can be adjusted by: adjusting the cavity length through the opening at the outer side of the end flange.

[0015] In yet another aspect, an apparatus is provided that includes: a housing that includes an input port and an output port; a plurality of adsorbent beds in the housing; a first rotary valve that connects the plurality of adsorbent beds to the input port for selectively transferring input gas from the input port to a selected one of the plurality of adsorbent beds; and a second rotary valve that connects the plurality of adsorbent beds to the output port for transferring output gas from a selected one of the plurality of adsorbent beds to the output port. The first rotary valve and the second rotary valve include the rotary valves disclosed herein.

[0016] Other aspects, features, and embodiments of the present disclosure will become apparent to those of ordinary skill in the art upon reading the following description of specific embodiments in conjunction with the accompanying drawings. Description of the Drawings

[0017] In the drawings, which illustrate embodiments of the present disclosure by way of example only:

[0018] Figure 1is a schematic block diagram of a rotary valve showing an embodiment of the present disclosure;

[0019] Figure 2A is of an embodiment according to the present disclosure Figure 1 schematic cross-sectional view of an embodiment of an end flange in a rotary valve;

[0020] Figure 2B is a top plan view of an exemplary end flange according to an embodiment of the present disclosure;

[0021] Figure 2C is Figure 2B bottom plan view of the end flange;

[0022] Figure 3A is of an embodiment according to the present disclosure Figure 1 perspective view of an embodiment of a spring tension adjuster in a rotary valve;

[0023] Figure 3B is Figure 3A bottom view of the spring tension adjuster;

[0024] Figure 3C is Figure 3A side view of the spring tension adjuster;

[0025] Figure 4A is of an embodiment according to the present disclosure Figure 1 schematic cross-sectional view of an embodiment of a stator with a seal in a rotary valve;

[0026] Figure 4B is a top plan view of an exemplary integrated stator and seal according to an embodiment of the present disclosure;

[0027] Figure 4C is Figure 4B bottom view of the stator and seal;

[0028] Figure 5 is a partial cross-sectional view of an embodiment of a rotary valve including Figure 2B and Figure 2C an exemplary end flange, a compression spring, Figures 3A to 3C an exemplary spring tension adjuster, and Figures 4A to 4C an exemplary stator and seal assembly; Figure 1 is a partial cross-sectional view of an embodiment of a rotary valve;

[0029] Figure 6 is a cross-sectional view of a part of another embodiment of a rotary valve having multiple compression springs Figure 1 ;

[0030] Figure 7A and Figure 7B is Figure 6Partial view of a portion showing a spring tension adjuster in different positions to adjust the length of a compression spring (and thus the tension therein);

[0031] Figure 8A and Figure 8B is Figure 6 Partial view of a portion showing a spring tension adjuster in different positions to adjust the relative position of a compression spring;

[0032] Figure 9A is Figure 6 Exploded perspective view of a part of a rotary valve;

[0033] Figure 9B is Figure 6 Exploded cross - sectional view of a part of a rotary valve;

[0034] Figure 10 Schematic diagram of a pressure swing adsorption (PSA) system having a rotary valve connected to a plurality of adsorbent beds according to an embodiment of the present disclosure;

[0035] Figures 11A to 11B Top view and side view of an example spring tension adjuster according to an embodiment of the present disclosure;

[0036] Figures 12A to 12B Top view and side view of another example spring tension adjuster according to an embodiment of the present disclosure; and

[0037] Figure 13A and Figure 13B Top view and side view of another example spring tension adjuster according to an embodiment of the present disclosure. Detailed Description

[0038] The example embodiments disclosed herein relate to a rotary valve having a spring - loaded pressurizing and sealing mechanism.

[0039] One embodiment is a rotary valve 100 schematically illustrated as Figure 1 The rotary valve 100 includes a valve housing 102 having a cylindrical channel 104 for mounting other valve components therein, the cylindrical channel 104 having an open end 106 and an end flange 110 attached to the housing 102 at the open end 106. The housing also has an output port 108 and an input port 107. The input port can include one or more ports and can be arranged on the flange 110 as described below.

[0040] Figure 5 An example embodiment of the rotary valve 100 is partially shown in. In this example embodiment, as Figures 2A to 2CAs can be better seen in, the end flange 110 has a pressure port 111, a fluid port 112, and a through hole 114 that extends from the outer side 113 of the flange 110 to the inner side 115 of the flange.

[0041] The pressure port 111 is configured and adapted to apply a variable sealing pressure as in a conventional face seal rotary valve and will be further described below. The port 111 can serve as both an inlet and an outlet for exhaust gas.

[0042] The fluid port 112 can include one or more ports that serve as input ports.

[0043] The through hole 114 has a first open end 116 located at the inner side 115, a second open end 118 located at the outer side 113, and a threaded section 119 located between the open ends 116, 118. The end flange 110 serves as a packing flange, which will become clear below. The open end 116 can have a cylindrical hole with a diameter larger than the diameter of the threaded section 119.

[0044] In some embodiments, as Figures 2A to 2C shown, each through hole 114 of the end flange 110 can include two sections with different diameters, as Figure 2A better illustrated. In particular, the through hole 114 can include a thicker or enlarged section 114A for receiving the spring 150 (which allows the spring to have a larger diameter dimension) and a thinner threaded section 114B for coupling the threaded spring tension adjuster 160.

[0045] In this embodiment, as will be further described below, the threaded tension adjuster 160 can also include a threaded stud with an enlarged end 164 for abutting the end of the spring 150. When the diameter of the threaded stud is smaller than the diameter of the spring 150, even when smaller than the inner diameter of the coil spring, the enlarged end 164 allows for better contact and support. The enlarged end 164 can be planar or chamfered. The threaded tension adjuster 160 can be formed of stainless steel.

[0046] According to conventional flange mounting or attachment techniques, the end flange 110 can be removably attached to the valve housing 102 in any suitable manner such as by bolts and nuts.

[0047] The end flange 110 can be formed of any suitable material for sealing a face seal rotary valve such as stainless steel.

[0048] The rotor 120 is rotatably mounted in the passage 104 of the housing 102 and is rotatable about the axis of rotation A. The rotor 120 includes an inner contact surface 122 substantially perpendicular to the axis of rotation A and an opposite outer surface 124. One or more fluid ports 126 extend through the rotor 110 between the surface 122 and the surface 124. The rotor can be connected to the rotor shaft 190 and actuated by the rotor shaft 190 to rotate. The rotor shaft 190 can be driven by a motor (not shown).

[0049] As can be appreciated, the valve 100 can also include different drive mechanisms for rotating the rotor 120. The drive mechanism can be provided according to any known technique and is not described in detail herein.

[0050] The stator 130 is slidably mounted within the passage 104 of the valve housing 102 between the end flange 110 and the rotor 120. As Figure 1 and Figures 4A to 4C depicted, the stator 130 has an inner side 132 facing the contact surface 122 of the rotor 120 and an outer side 134 opposite the inner side 132 and facing the end flange 110. The outer side 134 of the stator 130 includes a spring seat 136, a pressure port 137, and a fluid port 138, which are positioned and sized to correspond to the through hole 114, the pressure port 111, and the fluid port 112 of the flange 110, respectively. The fluid port 138 can extend through the stator 130 for selectively delivering fluid to the corresponding fluid port in the rotor 120. As described further below, the pressure port 137 and the fluid port 138 can each include an enlarged section as depicted in the drawings for forming a half piston chamber to receive the corresponding pressure piston.

[0051] The stator 130 can be attached or mounted in the valve housing 102 in any suitable manner such as contacting and fixed relative to the flange 110. For example, the stator 130 can be fixed to a stator housing (not shown) by welding or adhesive bonding. The stator 130 or its housing should be slidably and sealingly mounted in the valve housing 102 such that there is no fluid path through any gap between the stator 130 and the housing wall of the housing 202, and the only fluid path leading to the rotor side of the rotary valve 100 is through the fluid port 138 of the stator 130 and then through the fluid port 126 of the rotor 120. This sealing arrangement prevents undesired and uncontrolled gas leakage through the valve 100.

[0052] A seal 140 is provided and sandwiched between the inner contact surface 122 of the rotor 120 and the inner side 132 of the stator 130. In an embodiment, as Figures 4A to 4CAs shown, the seal 140 can be integrated with the stator 130 and disposed on the inner surface 132 of the stator 130. The seal 140 is compressed by the rotor 120 and the stator 130 and provides a fluid seal to prevent leakage of gas or liquid through the interface between the rotor 120 and the stator 130 during operation, including when the rotor 120 rotates relative to the stator 130 to open or close the valve 100. As will be further described below, the pressure applied to the seal 140 can be adjusted by applying pressure or a biasing force to the stator 130. Optionally, in some embodiments, the seal 140 can be provided as a separate layer. In other embodiments, the seal 140 can be a coating applied to the inner surface 122 of the rotor 120 or the inner side 132 of the stator 130, or a layer integrated with the inner surface 122 of the rotor 120 or the inner side 132 of the stator 130.

[0053] The seal 140 can be formed of a low-friction material. For example, the seal 140 can include graphite, carbon, or polytetrafluoroethylene (PTFE).

[0054] It can be understood that the corresponding materials for the seal or the mating surfaces of the rotor and stator for sliding contact can include a ceramic or a hardened metal alloy for one of the two contact surfaces, and carbon or a self-lubricating polymer for the other contact surface to minimize friction and wear.

[0055] As Figure 4B shown, the seal 140 can have corresponding openings that match the pressure port 137 and the fluid port 138 on the stator 130.

[0056] The compression spring 150 can be a helical spring received in the through-hole 114 of the end flange 110 and the spring seat 136 of the stator 130. As depicted, the first end 152 of the spring 150 is seated on the spring seat 136 of the stator 130, and the second end 154 of the spring 150 is in the through-hole 114. The spring 150 extends through the first open end 116 of the end flange 110. Suitable example compression springs include heavy-duty compression springs available from Associated Spring Raymond TM such as model 106 - 510 (extra-heavy-duty die springs).

[0057] A spring tension adjuster 160, such as a threaded packing stud or threaded bolt, is threadedly coupled to a threaded section 114B in a through-hole 114 of an end flange 110. The spring tension adjuster 160 is positioned to bias toward the stator 130 and press against the spring 150. The spring 150 is thus compressed between the end flange 110 and the stator 130. At least one cylindrical portion or gland portion of the spring tension adjuster 160 has an external thread to couple with the threaded section 114B such that the spring tension adjuster 160 can be rotated to adjust its relative axial position within the through-hole 114. By moving axially and repositioning the end 154 of the spring 150, changing the axial position of the spring tension adjuster 160 within the through-hole 114 will increase or decrease the tension of the spring 150 compressed between the stator 130 and the end flange 110. Compressing the spring 150 also increases the force applied at the sealing surface.

[0058] As can be understood, the through-hole 114 in the end flange 110 and the spring tension adjuster 160 provide a spring cavity with an adjustable cavity length. By rotating the adjuster 160 with a manual tool such as a screwdriver, the cavity length can be adjusted through an opening at the second open end 118 on the outer side of the end flange 114.

[0059] As Figures 3A to 3C shown, the spring tension adjuster 160 can be a threaded stud having a generally cylindrical body 162. The spring tension adjuster 160 can optionally have an enlarged end 164 for abutting the spring 150.

[0060] To facilitate rotating the spring tension adjuster 160 from the outer side of the flange 110, the outer end of the spring tension adjuster 160 can have a groove 166 configured to allow a tool such as a flat-head screwdriver (not shown) to rotate the spring tension adjuster 160 about its central axis, as Figure 3B and Figure 3C shown.

[0061] In different embodiments, the recess 166 can be replaced by different recesses such as cross-recesses or hexagon holes, so that the spring tension adjuster 160 can be rotated with a Phillips screwdriver or hexagon screwdriver or similar tool. In further embodiments, other types of screw heads or bolt heads can be provided at the outer end to allow a corresponding tool to apply torque on the head to rotate the spring tension adjuster 160.

[0062] In some embodiments, the spring tension adjuster 160 can comprise a straight cylinder with a threaded outer surface.

[0063] As Figure 5 、 Figure 7A and Figures 9A to 9BAs shown, a removable cap 180 can be provided to cover the open end 118 of the through hole 114.

[0064] Internal pressure is applied in the pressure ports 111 and fluid ports 112 to apply a sealing pressure on the stator 130 and, in turn, on the seal 140. The internal pressure also provides a biasing force to bias the stator 130 towards the rotor 120.

[0065] The fluid port 112 in the flange 110 and the fluid port 138 in the stator 130 are aligned and correspondingly configured to allow fluid to be conveyed through the flanges 110 and 130.

[0066] When the rotor 120 rotates to a position where the fluid port 138 of the stator 130 is aligned with the corresponding fluid port 126 in the rotor 120, the rotary valve 100 opens and fluid can flow therethrough. When the rotor 120 rotates to a position where the fluid port 138 of the stator 130 is completely offset from the corresponding fluid port 126 in the rotor 120, the rotary valve 100 closes and fluid cannot flow through the rotary valve 100.

[0067] Figure 5 A partial view of the components described above as assembled is shown.

[0068] As depicted, the rotary valve 100 can include multiple pairs of pressure ports 112 in the flange 110 and the stator 130.

[0069] When multiple fluid ports are provided in a single rotary valve, the rotary valve can provide fluid paths for multiple fluid lines, which can be connected to, for example, multiple different reaction beds or vessels.

[0070] In the rotary valve 100, at least one fluid path extending through the rotor 120 and the stator 130 is provided. In some embodiments of the rotary valve, multiple fluid paths can be provided.

[0071] For balancing purposes, internal pressure can be applied to apply a variable loading pressure or biasing force on the stator 130. The loading pressure or biasing force applied in a particular port can depend on the fluid pressure in the corresponding pressure port 112. The higher the fluid pressure, the greater the loading pressure or biasing force applied to the stator 130 and, in turn, to the seal 140. Thus, a tighter seal at the sealing interface between the rotor 120 and the stator 130 is created by a higher fluid pressure in the pressure ports 112. The fluid pressures in different pressure ports 112 can be different or can be the same.

[0072] Figure 6 Different embodiments of the rotary valve 100 having two or more compression springs 150 are shown.

[0073] As depicted, multiple springs and corresponding spring seats can be provided in the rotary valve. For example, one of the springs 150 can be positioned adjacent each fluid port and can be independently compressed by a corresponding spring tension adjuster (see also Figure 2C and Figure 4C ).

[0074] It can now be understood that valve 100 is a face-sealed rotary valve and has a pressure-balanced rotary face seal between rotor 120 and stator 130.

[0075] The size and pitch of the threads on the threaded tension adjuster 160 and the threaded section can be selected based on a number of factors and the specific application in which valve 100 is used. The threads can be standard fine threads according to the Unified National Fine (UNF) standard. For fine threads, the stress on the low-friction seal 140 can be fine-tuned and customized for each application. During operation, such fine-tuning and convenient adjustment of such stress can reduce wear and degradation of the sealing material in the seal 140 and can provide optimal performance for different conditions and applications.

[0076] As shown in the figure, multiple springs 150 can be provided. The springs 150 can be provided at different distances from the central axis A of the stator 120.

[0077] In a pressure-balanced rotary face seal, springs are a common method of applying activation force. This force is required to clamp the closed components so that the surfaces can seal. For dynamic applications, determining this activation force can be difficult. For example, although different springs of different strengths or lengths can be used to determine the appropriate activation force through trial and error, such determination will require repeated stopping and restarting of sealing and pressurization, as well as repeated disassembly and reassembly of the pressure system and the rotary valve, which is not only inconvenient and time-consuming, but also reduces production efficiency and increases the risk of introducing various system operation problems during this period.

[0078] In the embodiments disclosed herein, multiple activation springs can be used, each activation spring being provided with a mechanical adjustment mechanism to adjust the spring tension by changing the cavity depth or length of the spring cavity in which the activation spring is mounted. By controlling the change in spring tension, the activation force and pressure applied by the spring to the seal interface are changed or adjusted. The mechanical adjustment mechanism is configured such that the depth or length of the spring seat can be adjusted in situ by rotating the end flange of the valve without removing the valve from the operating system and disassembling the valve. The adjustment can be made using a simple tool such as a screwdriver-like driver.

[0079] Conveniently, such adjustability allows a user or operator to dynamically change the compression length of an individual spring and the compression force or tension on an individual spring by easily turning or rotating the threaded tension adjustment member using a tool or driver.

[0080] With such adjustability, when the required biasing pressure at the seal interface changes, there is no need to replace the spring to increase or decrease the applied pressure by using a stiffer or softer spring. Thus, to change the biasing pressure applied by the spring to the stator, there is no need to pause or stop the production operation and disassemble the assembly or remove the valve at the seal interface. Adjustments can also be made relatively quickly and more conveniently.

[0081] Dynamically adjusting the spring compression length and the corresponding biasing pressure allows the pressure applied to the seal interface to be balanced and that balance to be maintained over an extended period. For example, when a higher sealing force or biasing force is required, such as due to physical wear, aging, or deterioration of the material at the seal interface, the sealing force or biasing force can be conveniently and quickly adjusted to apply an increased sealing force or pressure.

[0082] In some embodiments and applications, the position of the seal spring can also be changed, with or without changing the compression length of the spring, such that the spring is relatively positioned closer to or farther from the seal interface. This adjustment may be convenient, for example, when the distance between the end flange and the seal interface changes due to the aforementioned wear of the material at the seal interface over time.

[0083] As Figure 2B 、 Figure 2C 、 Figure 4B and Figure 4C shown, fluid ports 112, 138, and 126 can be arranged in a circle (port pitch circle) centered on axis A and spaced equidistantly around the pitch circle. In the depicted embodiment, the fluid ports provide 12 different fluid paths.

[0084] As can be appreciated, pressure ports 112 that are designed to be smaller in size and evenly distributed and are coupled to multiple distributed compression springs 150 can provide improved pressure balance compared to ports that are designed to be larger in size at locations of less pressure.

[0085] Also as indicated by Figure 2B and Figure 2C the through - holes 114 shown in Figure 4C and

[0086] Figure 4C the spring seats 136 shown in

[0086] The internal compression spring 150 can be arranged on an inner pitch circle centered on the central axis A and having a pitch circle diameter smaller than the port pitch circle, and the external compression spring 150 can be arranged on an outer pitch circle centered on the central axis A and having a pitch circle diameter larger than the port pitch circle.

[0087] In some embodiments, the springs 150 on the inner and outer pitch circles can be the same. In other embodiments, the spring 150 on the inner pitch circle can be different from the spring on the outer pitch circle. For example, for better balance, the internal spring 150 can be tensioned to apply a smaller biasing force or closing force to the stator 130 than the outer spring 150. Different spring tensions can be achieved by using springs with different sizes (diameter or length), different spring constants, or formed of different materials, or combinations thereof. Conveniently, as described herein, the spring tension can additionally or alternatively be adjusted by the spring tension adjuster 160.

[0088] Figure 7A and Figure 7B Illustrated is the adjustment of the spring 150 by positioning the spring tension adjuster 160 at different axial positions. Figure 7B Shown is the spring 150 at minimum tension when the spring tension adjuster 160 is positioned at the bottom of the spring cavity and the spring 150 extends to its maximum length allowed by the distance between the flange 110 and the stator 130. Figure 7A Shown is that the spring 150 can be further compressed by positioning the spring tension adjuster 160 closer to the stator 130 such that the length of the spring is less than Figure 7B the length shown in Figure 7A and Figure 7B In both cases, the length of the spring 150 is less than its free length (or free height), so there is always some tension in the spring 150 during operation.

[0089] Figure 8A and Figure 8B Illustrated is the adjustment of the position of the spring 150 by positioning the spring tension adjuster 160 at different axial positions with or without changing the tension of the spring 150. Figure 8A Shown is the spring 150 in a first position. Figure 8B Shown is the spring 150 in a second position after the stator 130 has moved slightly upward towards the rotor 120 due to wear of the seal 140. However, in Figure 8A and Figure 8B In both cases, by correspondingly adjusting the position of the spring tension adjuster 160 upward by the same distance, the working length (or working height) of the spring 150 is the same. Thus, even if the spring 150 is displaced due to the movement of the stator 130, Figure 8A and Figure 8BThe spring tension in both is also the same.

[0090] Figure 9A and Figure 9B is an exploded partial view of flange 110, stator 130, spring 150, spring tension adjuster 160, and removable cap 180.

[0091] The exemplary rotary valve 100 depicted can be used in a PSA apparatus including twelve (12) adsorbent beds.

[0092] For example, as Figure 10 shown, the PSA apparatus 200 can include a plurality of adsorbent beds 201, such as twelve adsorbent beds (not shown individually), and two rotary valves 100. One of the rotary valves 100 is connected to the feed end 202 of the adsorbent bed 201 and the other rotary valve 100 is connected to the output or product end 204 of the apparatus 201. The feed end 202 can include twelve individual conduits (not shown individually), each conduit being in fluid communication with one of the twelve fluid ports 138 of the stator 130 in the rotary valve 100. The product end 204 can also include twelve individual conduits (not shown individually), each conduit being in fluid communication with one of the twelve fluid ports 138 of the stator 130 in the rotary valve 100 at the product end. The twelve conduits at each of the feed end 202 and the product end 204 can be individually connected to the twelve adsorbent beds in the PSA apparatus 200, respectively, thereby forming fluid paths connecting the corresponding fluid ports 138 of the two rotary valves 100 through the corresponding adsorbent beds (not shown) in the PSA apparatus 200. The PSA apparatus 200 can optionally include other fluid ports, such as an output port 206.

[0093] Those skilled in the art will understand that the different embodiments of the rotary valve described herein can be configured or modified to be applied to PSA apparatuses having different numbers of adsorbent beds, or to other chemical processing systems having any number of reaction vessels.

[0094] In different embodiments, the fluid ports and pressure ports in the rotary valve can have different shapes and can be located on different port pitch circles.

[0095] Figures 11A to 13B Different embodiments of the spring tension adjuster 160 are illustrated. For example, as Figure 11A and Figure 11B shown, the spring tension adjuster 1100 can include a threaded stud 1102 with an anchoring head 1104. As Figure 12A and Figure 12B shown, the spring tension adjuster 1200 can also include a threaded bolt 1202 with a bolt head 1204. Figure 13A andFigure 13B Another spring tension adjuster 1300 with bolts 1302 and bolt heads 1304 is illustrated. The spring tension adjuster 160 may alternatively include a pipe or sleeve with external threads and a solid outer end or head for rotation by a suitable tool.

[0096] It will now be appreciated that the embodiments disclosed herein utilize a mechanical spring tension adjuster to increase or decrease the tension or position of a compression spring that applies additional sealing pressure or force to a seal interface between a rotor and a stator of a face-sealed rotary valve. This varying spring chamber gives the seal interface pressure infinite adjustability, allowing for optimal seal performance and long service life, while minimizing downtime and eliminating the need for disassembly and reassembly.

[0097] In a typical pressure swing adsorption process, different gases in an air stream can be separated by passing the air stream containing a mixture of different gases through an adsorbent typically placed in an adsorbent bed, where at a selected pressure, the adsorbent preferentially adsorbs one or some of the component gases in the mixture and substantially does not adsorb at least one other component gas in the component gases of the mixture. Then, the unadsorbed component(s) can be recovered as a product air stream. The pressure on the adsorbent can then be reduced to release (i.e., desorb) the adsorbed component(s), and the adsorbed component(s) can then be collected and recovered as another product air stream. The adsorbent can be regenerated and cleaned after a production cycle and reused in another adsorption-desorption cycle.

[0098] The rotary valve assembly in a PSA system can include one or more rotor / stator pairs, each rotor / stator pair having a plurality of circumferentially arranged holes called fluid ports, the plurality of circumferentially arranged holes being configured and positioned to allow synchronous fluid communication between the regions of the adsorbent bed separated by the rotor / stator pair. The fluid ports can be selected such that they have an effective size and an effective shape to allow for balancing fluid flow and controlling fluid flow rate by adjusting the relative rotational speed of the rotor / stator pair.

[0099] A pressure swing adsorption (PSA) apparatus can include, for example, a rotor connected to or provided with a plurality of adsorbent beds, a stator having a plurality of conduits serving as fluid ports, and a seal positioned between the rotor and the stator.

[0100] In various embodiments, the rotary valves disclosed herein can be used in any pressure swing adsorption system or process. For example, the pressure swing adsorption process can be any of the following types of pressure swing adsorption: pressure swing adsorption (PSA), partial pressure pressure swing adsorption (PPSA), rapid cycle pressure swing adsorption (RCPSA), rapid cycle partial pressure pressure swing adsorption (RCPPSA), vacuum pressure swing adsorption (VPSA), etc. The pressure swing adsorption process can also be temperature swing adsorption (TSA), rapid cycle temperature swing adsorption (RCTSA), or pressure swing adsorption / temperature swing adsorption.

[0101] The pressure swing adsorption process can occur in a cylindrical container housing multiple adsorbent beds. Each adsorbent bed can be in a different stage of a production or adsorption cycle that can include a pressurization / adsorption stage, one or more depressurization / desorption stages, one or more blowdown stages, and one or more repressurization stages. The flow of fluid to and from each adsorbent bed can be controlled by using a suitable valve that includes a rotary valve. The rotary valve can be configured as disclosed herein.

[0102] The rotary valves disclosed herein can also be used in an efficient manner to set up multiple process valves required for combining or integrating repeated chemical treatment cycles in a single container in various applications. The rotary valves disclosed herein can also be used in various chemical treatment operations involving pressure swing processes or apparatuses. For example, multiple reaction sites such as adsorbent beds or catalyst beds in a single container can be associated by a single rotor / stator pair having multiple ports, and the rotor and stator can be operated at different rotational speeds to provide a desired fluid flow.

[0103] The cyclic adsorption process can also be performed in one or more adsorption containers filled with adsorbent. Two or more containers can optionally be arranged in parallel and time synchronized such that at least one container is in the adsorption stage while at least another container is in the adsorbent regeneration stage. In each cycle of the process, a series of consecutive stages such as adsorption, equilibration, and regeneration are performed in each container. To enable various material streams to flow to and from the containers, feed lines, product lines, and bleed lines can be provided with rotary valves as described herein for controlling and regulating the gas flowing through these lines at appropriate times during the adsorption cycle. The rotary valves as described herein can also be used to allow fluid communication between multiple inlets and outlets of the same or different containers, such as during a pressure equilibration stage.

[0104] The rotary valves described herein can be used with any suitable adsorbent bed for separating a target gas from a gas mixture.

[0105] The PSA system can be configured and constructed according to any suitable known technology. For example, the adsorbent bed in a suitable PSA system can comprise a bed of bead or pellet adsorbent particles or adsorbent material on a structured contactor such as a parallel channel contactor. The contactor can accommodate substantially parallel flow channels. The adsorbent can be incorporated into the walls of the flow channels.

[0106] In some embodiments, the rotor of the rotary valve can be configured to rotate with the associated adsorbent bed. In some embodiments, the rotor of the rotary valve can rotate, but when the rotor of the rotary valve rotates, the associated adsorbent bed(s) can remain stationary.

[0107] In different embodiments, the rotor 120 can have multiple fluid ports 126 for different functions. For example, as can be understood by those skilled in the art, the fluid ports 126 of the rotor 120 can include one or more feed ports, countercurrent discharge ports, and purge discharge ports. The fluid ports 126 of the rotor 120 can alternatively include one or more product ports, fluid extraction ports, or fluid return ports.

[0108] It should be understood that although the rotor and the inner surface or the inner side of the stator depicted in the drawings are depicted as flat and planar surfaces or sides, in different embodiments, the contact surface or side between the rotor and the stator and the sealing interface or layer between the rotor and the stator can have different geometries. For example, the contact surface and the sealing layer can be inclined, such as conical, or can be cylindrical or in the shape of other rotational surfaces.

[0109] The rotary valves and PSA devices disclosed herein can be used in different applications, such as hydrogen separation, air separation, oxygen production, and other gas or vapor separations. For example, they can be used in applications for recovering hydrogen from refinery off-gases or syngas, or for hydrogen purification applications.

[0110] It should also be understood that modifications and variations to the specific embodiments described above are possible.

[0111] Conclusion

[0112] It should be understood that the drawings are not necessarily drawn to scale, and some features may be enlarged or minimized to show details of particular parts. Therefore, the specific structural and functional details disclosed herein should not be construed as restrictive, but merely as a representative basis for teaching those skilled in the art to adopt the subject matter disclosed herein.

[0113] Additionally, any specific numerical values listed herein include a margin of error of + / - 10%.

[0114] In this disclosure, terms such as "horizontal" and "flat" do not necessarily require the associated structure to be perfectly horizontal or flat. Rather, these terms are intended to encompass, for example, structures that are generally and sufficiently horizontal or flat to function substantially the same as a perfectly horizontal or flat structure.

[0115] It will be understood that any numerical range herein is intended to specifically include any intermediate value or sub-range within the given range, and all such intermediate values and sub-ranges are individually and specifically disclosed.

[0116] It will also be understood that the word "a" or "an" is intended to mean "one or more" or "at least one" and any singular form herein is intended to include the plural.

[0117] It will further be understood that, unless specifically indicated to the contrary otherwise, the term "comprising", including any of its variants, is intended to be open-ended and means "including, but not limited to".

[0118] When a list of items is given herein with "or" preceding the last item, any one of the listed items or any suitable combination of two or more of the listed items may be selected and used.

[0119] Of course, the above-described embodiments of the present disclosure are only illustrative and in no way limiting. The described embodiments are susceptible to many modifications in form, arrangement of parts, details, and order of operation. Rather, the present invention is intended to cover all such modifications within its scope as defined by the claims.

Claims

1. A rotary valve, which comprises: a valve housing including a cylindrical passage and an end flange, the end flange including a pressure port and a through hole having a first open end and a second open end and a threaded section between the first end and the second end; a rotor rotatably mounted in the cylindrical passage of the valve housing and capable of rotating about a rotation axis, the rotor including a contact surface substantially perpendicular to the rotation axis; a stator slidably mounted inside the valve housing between the rotor and the end flange, the stator including a first side facing the contact surface of the rotor and a second side opposite the first side, the second side of the stator including a spring seat; a spring including a first end and a second end, the first end of the spring received in the spring seat of the stator, the second end of the spring passing through the first open end of the through hole and received in the through hole of the end flange; a spring tension adjuster threadedly coupled to the threaded section in the through hole of the end flange and pressing the spring towards the stator, the stator in turn being pressed towards the rotor by the spring, the spring tension adjuster being configured to be rotatable through the second open end of the flange to change the axial position of the spring tension adjuster so as to adjust the tension of the spring compressed between the stator and the end flange.

2. The rotary valve according to claim 1, wherein, the stator includes a pressure port.

3. The rotary valve according to claim 1 or 2, wherein, each of the flange and the stator includes a plurality of pressure ports, and the rotary valve includes a plurality of pressure ports for biasing the stator towards the rotor.

4. The rotary valve according to any one of claims 1 to 3, wherein, each of the rotor and the stator includes a plurality of fluid ports.

5. The rotary valve according to claim 4, which includes a plurality of springs and a plurality of corresponding spring tension adjusters.

6. The rotary valve according to claim 5, wherein, each of the springs is positioned adjacent to one of the plurality of fluid ports and is independently compressed by the corresponding spring tension adjuster.

7. The rotary valve according to claim 1, wherein, the spring tension adjuster includes a threaded stud.

8. The rotary valve according to claim 1, wherein, the spring tension adjuster includes an externally threaded tube or sleeve.

9. The rotary valve according to any one of claims 1 to 8, which includes a seal compressed between the rotor and the stator.

10. The rotary valve according to any one of claims 1 to 9, wherein, the spring tension adjuster includes stainless steel.

11. The rotary valve according to any one of claims 1 to 10, which includes a removable cap covering the second open end of the through hole.

12. A rotary valve, which comprises: a valve housing including a cylindrical passage and an end flange, the inner side of the end flange including a spring cavity having an adjustable cavity length that can be adjusted through an opening at the outer side of the end flange; A rotor rotatably mounted in a cylindrical passage of the valve housing and capable of rotating about a rotation axis, the rotor including a contact surface generally perpendicular to the rotation axis; A stator slidably mounted inside the valve housing between the rotor and the end flange, the stator including a first side adjacent to the contact surface of the rotor and a second side opposite the first side; And A spring received in the spring chamber and compressed between the end flange and the second side of the stator to bias the stator toward the rotor, wherein the tension in the spring can be adjusted by adjusting the chamber length through the opening at the outer side of the end flange.

13. An apparatus, which Comprises: A housing including an input port and an output port; A plurality of adsorbent beds in the housing; A first rotary valve connecting the plurality of adsorbent beds to the input port for selectively transferring input gas from the input port to a selected one of the plurality of adsorbent beds; A second rotary valve connecting the plurality of adsorbent beds to the output port for transferring output gas from the selected one of the plurality of adsorbent beds to the output port; Wherein the first rotary valve and the second rotary valve include a rotary valve according to any one of claims 1 to 12.

Images