Low-disturbance high-precision special program-controlled valve for oxygen separation of lithium-based molecular sieve

Abstract

This invention discloses a low-disturbance, high-precision dedicated programmable valve adapted for oxygen separation using lithium-based molecular sieves, belonging to the field of valve technology for vacuum pressure swing adsorption (PSA) oxygen generation. Addressing the problems of large opening and closing impacts, lack of micro-powder protection, unreliable vacuum sealing, and easy valve position drift in existing general-purpose programmable valves, this invention proposes the following technical solution: A four-segment independently adjustable damping flexible buffer opening and closing module is provided on the pneumatic actuator, enabling the valve opening and closing speed curve to exhibit a segmented pattern of slow pressure build-up, uniform and stable operation, gradual pressure reduction, and soft landing closure; an annular mounting groove for a sealing element is provided on the inner wall of the valve body's inlet air passage, with a sealing element embedded within the groove. The surface of the sealing element facing the streamlined rectifier valve plate serves as the inner wall contact surface of the sealing element, and a U-shaped cross-section elastic metal ring is embedded inside the sealing element to press the inner wall contact surface of the sealing element against the outer peripheral wall of the streamlined rectifier valve plate; a guide bearing and a stuffing box sealing assembly are provided between the upper neck mounting cylinder and the valve stem. This invention fundamentally eliminates opening and closing impacts and pressure oscillations, effectively solves the sealing failure problem caused by micro-powder scouring and deposition, and locks negative pressure in the high vacuum range for a long time to ensure thorough desorption of molecular sieves, while ensuring that the valve stem maintains a precise fit for a long time to avoid valve position drift.

Description

Technical Field

[0001] This invention relates to the field of valve technology for vacuum pressure swing adsorption oxygen generation, specifically to a low-disturbance, high-precision dedicated programmable valve adapted for lithium-based molecular sieve oxygen separation. Background Technology

[0002] Vacuum pressure swing adsorption (VPSA) oxygen generation technology is one of the mainstream processes for oxygen production in industrial settings. Its core principle is to utilize the selective adsorption differences of adsorbents on nitrogen and oxygen in the air, achieving oxygen-nitrogen separation through periodic pressure alternation. Programmable valves, as the actuators responsible for key stages in VPSA oxygen generation equipment such as adsorption tower sequence switching, pressure equalization, and vacuum desorption, directly affect the operational stability and energy consumption of the entire oxygen generation system. In recent years, lithium-based molecular sieves, with their advantages of high adsorption capacity and strong nitrogen selectivity at low pressure, are gradually replacing traditional sodium-based molecular sieves as the core adsorption medium for the new generation of high-efficiency VPSA oxygen generation equipment. They can achieve efficient nitrogen-oxygen separation under normal pressure with slight positive pressure adsorption and low vacuum conditions, significantly improving overall energy consumption and oxygen recovery rate compared to traditional systems.

[0003] Currently, the programmable valves used in conjunction with lithium-based molecular sieve oxygen generation equipment are still general-purpose valve products designed for traditional sodium-based molecular sieve operation. Taking common two-stage buffer programmable butterfly valves and ordinary quick-switching valves as examples, these valves have not been structurally optimized for the process characteristics of lithium-based molecular sieve oxygen generation systems, and mainly have the following defects: The large impact of opening and closing disrupts the adsorption balance. Traditional valves generally use a cylinder to directly drive the valve plate for rapid opening and closing. During the opening and closing process, the valve plate speed is uncontrollable and the movement is highly discrete. This generates violent pressure fluctuations and water hammer effects at the moment of opening and closing, causing pressure oscillations within the adsorption tower. Since lithium-based molecular sieves rely on precise micro-pressure differences to achieve efficient nitrogen adsorption, they are highly sensitive to pipeline airflow disturbances and pressure fluctuations. This rigid impact directly disrupts the pressure balance of the low-pressure adsorption section, reduces the nitrogen adsorption capacity, and negates the energy-saving and high-efficiency advantages of lithium-based molecular sieves.

[0004] The sealing structure lacks consideration for microparticle protection, leading to severe wear and leakage. Lithium-based molecular sieves have fine particles and a high microparticle yield, and the low-pressure, high-speed airflow easily carries microparticles, forming a powder-laden airflow that causes scouring and deposition at the flow channel and sealing surface. The sealing pairs and valve cavity structures of traditional valves are not designed for powder-laden airflow conditions, lacking measures to guide and protect against microparticles. After long-term operation, the sealing surface is prone to wear, and powder easily accumulates in the dead corners of the valve cavity, resulting in valve sealing failure, inter-tower cross-ventilation, and a continuous decline in oxygen production stability and purity.

[0005] The sealing reliability under vacuum desorption conditions is insufficient. Lithium-based molecular sieves require complete desorption and regeneration within a high vacuum range of -0.08 MPa to -0.09 MPa, placing extremely high demands on the sealing durability of valves under negative pressure. Traditional valve sealing structures are primarily designed for positive pressure conditions. Under alternating high vacuum conditions, the seals are prone to deformation and loosening, resulting in limited negative pressure maintenance capabilities. This leads to unstable vacuum levels during the desorption phase, incomplete molecular sieve regeneration, accumulation of adsorbed residues, and a gradual reduction in oxygen production efficiency and molecular sieve lifespan.

[0006] Valve position drift under large-scale alternating high and low pressure conditions. The lithium-based oxygen generation cycle is a wide-range alternating condition of "micro-positive pressure adsorption - high vacuum desorption". The transmission and guiding structure of traditional valves is not optimized for this condition. After long-term exposure to alternating loads, gap expansion and valve position drift are prone to occur, resulting in asynchronous timing of multiple valves and failing to meet the millisecond-level precise programmable control requirements of lithium-based oxygen generation.

[0007] In summary, existing general-purpose programmable valves cannot accurately adapt to the special operating conditions of lithium-based molecular sieve oxygen generation systems in terms of opening and closing characteristics, sealing protection, vacuum pressure holding, and transmission durability, thus restricting the full realization of the low-energy consumption and high-recovery rate advantages of lithium-based molecular sieve technology. To address these issues, this invention proposes a low-disturbance, high-precision dedicated programmable valve adapted for oxygen separation using lithium-based molecular sieves. Summary of the Invention

[0008] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a low-disturbance, high-precision dedicated programmable valve adapted for oxygen separation using lithium-based molecular sieves, thus solving the problems existing in existing dedicated programmable valves adapted for oxygen separation using lithium-based molecular sieves.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solution: a low-disturbance, high-precision dedicated programmable valve adapted for oxygen separation using lithium-based molecular sieves.

[0010] Technical solutions to the problem of valve opening and closing impact disrupting adsorption balance To address the technical problem of pressure oscillations in the low-pressure adsorption section of lithium-based molecular sieves caused by sudden speed changes and rigid impacts during the opening and closing of traditional valves, this invention incorporates a flexible buffer opening and closing module on the cylinder of the pneumatic actuator. This module features four independently adjustable damping parameters. When the valve receives an opening command, the flexible buffer module controls the valve stem to initiate a slow-start pressure-building phase, causing the valve plate to slowly detach from the sealing surface at an ultra-low speed, allowing the pressure in the valve body's inlet air passage to build up steadily. Subsequently, it enters a uniform speed stabilization phase, where the valve plate continues to open at a uniform speed, ensuring efficient oxygen production. When the valve receives a closing command, the flexible buffer module controls the valve stem to sequentially pass through a slow-descent pressure relief phase, gradually reducing the valve plate speed, and then through a soft-landing closing phase, allowing the valve plate to adhere to the inner wall of the sealing element without impact. The four damping parameters are independently adjustable, allowing the speed and time of each phase to be set according to the specific adsorption and desorption sequence requirements of the lithium-based molecular sieve.

[0011] Preferably, the flexible buffer opening and closing module is integrated inside the pneumatic actuator cylinder, and four-stage speed control is achieved through the buffer chamber and throttling channel inside the pneumatic actuator cylinder; alternatively, the flexible buffer opening and closing module can also be set as an independent damping valve group module externally placed on the air supply pipeline of the pneumatic actuator cylinder.

[0012] Technical solutions to the problem of seal failure caused by micro powder erosion and deposition To address the technical problems of lithium-based molecular sieve micropowder eroding and wearing of the sealing surface under high-speed airflow, and depositing scale in the dead corners of the valve cavity, leading to sealing failure and jamming, this invention has made comprehensive improvements to the structure of the streamlined rectifier valve plate and the sealing component.

[0013] The streamlined rectifier valve plate features a rounded transition at the junction of its outer peripheral wall and two end faces, and its surface is mirror-polished. The side of the streamlined rectifier valve plate facing the valve body's inlet air passage has an airflow-facing arc surface, which is a full, convex arc shape. The side facing the valve body's outlet air passage has a smooth, flow-guiding back surface, which has a smooth transition shape, resulting in an asymmetrical streamlined configuration for the overall cross-section of the streamlined rectifier valve plate. When airflow passes through the streamlined rectifier valve plate, the rounded transition and mirror-polished surface work together to guide the airflow, preventing turbulence and powder entrainment caused by sharp corner disturbances.

[0014] An annular mounting groove for a sealing element is formed on the inner wall of the valve body's inlet air passage, and a sealing element is embedded within the groove. The surface of the sealing element facing the streamlined rectifier valve plate is the inner wall contact surface of the sealing element, which forms a full-circumferential contact seal with the outer peripheral wall of the streamlined rectifier valve plate when the valve is closed. A U-shaped elastic metal ring is embedded inside the sealing element, which presses the inner wall contact surface of the sealing element against the outer peripheral wall of the streamlined rectifier valve plate. When the inner wall contact surface of the sealing element wears due to long-term opening and closing friction, the U-shaped elastic metal ring continuously applies elastic force, ensuring that the inner wall contact surface of the sealing element remains in close contact with the outer peripheral wall of the streamlined rectifier valve plate, automatically compensating for wear.

[0015] The annular mounting groove of the seal is located at the junction of the inner wall of the valve body's inlet air passage and the central cavity. When the valve is open, the inner wall of the seal and the outer peripheral wall of the streamlined rectifier valve plate maintain a small purging gap. During the valve opening and closing process, the airflow pressure difference on both sides of the valve plate carries away the fine powder trapped at the sealing interface through this gap.

[0016] Technical solutions to the problem of unreliable vacuum desorption sealing To address the technical problems of traditional valves where the seals are prone to deformation and loosening in high vacuum ranges, and the inability to stably lock under negative pressure leads to incomplete desorption of molecular sieves, this invention further optimizes the sealing and maintaining capability under vacuum conditions in the mating structure of the seals and the streamlined rectifier valve plate.

[0017] The opening of the U-shaped cross-section elastic metal ring faces the outlet air passage of the valve body. When the valve is in vacuum desorption mode, the outlet air passage of the valve body is under negative pressure. This negative pressure acts on the inner wall of the opening of the U-shaped cross-section elastic metal ring, causing the U-shaped cross-section elastic metal ring to open further, enhancing its elastic compensation force on the inner wall contact surface of the seal. The seal adopts an integral molding structure of elastic matrix and wear-resistant low-friction composite layer. The surface of the seal facing the streamlined rectifier valve plate is the wear-resistant low-friction composite layer, and the rest of the seal is the elastic matrix. In the high vacuum range, the contact pressure between the inner wall contact surface of the seal and the outer peripheral wall of the streamlined rectifier valve plate increases with the increase of vacuum, forming a negative pressure self-locking sealing effect, which can stably lock the negative pressure in the tower for a long time.

[0018] Technical solutions for valve position drift under alternating high and low pressure conditions To address the technical problems of transmission clearance expansion, valve position drift, and multi-valve timing disorder in traditional valves under the alternating conditions of micro-positive pressure adsorption and high vacuum desorption, this invention incorporates a guide bearing and a stuffing box sealing assembly between the upper neck mounting cylinder and the valve stem.

[0019] The valve body has an upper neck mounting sleeve on its upper wall, and the valve stem passes through the upper neck mounting sleeve. A guide bearing is installed between the upper neck mounting sleeve and the valve stem. The guide bearing supports the radial positioning of the valve stem, ensuring that the valve stem remains coaxial with the upper neck mounting sleeve during rotation or lifting. A stuffing box seal assembly is also installed between the upper neck mounting sleeve and the valve stem to seal the gap between the valve stem and the upper neck mounting sleeve, preventing internal gas leakage along the valve stem. The guide bearing and valve stem have a zero-clearance precision fit, and the stuffing box seal assembly forms a dynamic seal at the valve stem protrusion point. This combination ensures that the valve stem maintains valve position accuracy over long-term under alternating high and low pressure impacts, avoiding timing drift caused by clearance expansion.

[0020] (III) Beneficial Effects This invention provides a low-disturbance, high-precision, dedicated programmable valve adapted for oxygen separation using lithium-based molecular sieves. It offers the following advantages: 1. Compared with the prior art, the low-disturbance, high-precision dedicated programmable valve for oxygen separation of lithium-based molecular sieves provided by the present invention, by setting a four-segment independently adjustable damping flexible buffer opening and closing module on the pneumatic actuator, makes the speed curve of the valve opening and closing process present a segmented mode of slow pressure build-up, uniform speed and steady movement, slow pressure relief, and soft landing closure. This fundamentally eliminates the speed change and rigid impact at the moment of opening and closing of traditional valves, effectively avoids pressure oscillation and airflow disturbance in the low-pressure adsorption stage, and ensures that lithium-based molecular sieves maintain a stable adsorption balance in a precise micro-pressure difference environment.

[0021] 2. Compared with the prior art, the low-disturbance, high-precision dedicated programmable valve for oxygen separation adapted to lithium-based molecular sieves provided by the present invention has a sealing ring mounting groove opened on the inner wall of the valve body inlet air passage and a sealing element embedded in the groove. This allows the inner wall of the sealing element to form a full-circumferential contact seal with the outer peripheral wall of the streamlined rectifier valve plate. A U-shaped cross-section elastic metal ring is embedded inside the sealing element to continuously press the contact surface against the outer peripheral wall of the valve plate. At the same time, a mirror polished surface and an arc transition structure are set on the surface of the valve plate to uniformly guide the powder-containing airflow and automatically compensate for the wear of the sealing surface. This effectively solves the sealing failure and jamming problems caused by the scouring and deposition of micro powder.

[0022] 3. Compared with the prior art, the low-disturbance, high-precision dedicated programmable valve for oxygen separation of lithium-based molecular sieves provided by the present invention, by having the opening of the U-shaped cross-section elastic metal ring face the outlet gas channel side, allows the negative pressure to act on the inner wall of the U-shaped ring under vacuum desorption conditions to assist it in further opening to enhance the elastic compensation force. Combined with the full-circumferential contact sealing structure between the inner wall of the sealing element and the outer peripheral wall of the valve plate, the negative pressure in the tower can be locked for a long time in the high vacuum range, preventing vacuum leakage and negative pressure attenuation, and ensuring that the vacuum desorption of lithium-based molecular sieves is sufficient and thorough.

[0023] 4. Compared with the prior art, the low-disturbance, high-precision dedicated programmable valve for oxygen separation adapted to lithium-based molecular sieves provided by the present invention achieves precise radial positioning of the valve stem and reliable sealing of the protruding part by setting a guide bearing and a stuffing box sealing assembly between the valve body neck mounting cylinder and the valve stem. It maintains a precise fit for a long time under alternating high and low pressure impacts, avoids valve position drift and timing disorder caused by gap expansion, and ensures that the opening and closing sequence of multiple valves is consistent within the millisecond precision range for a long time. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 A partial sectional view of the connection structure between the valve body, valve stem, and streamlined rectifier valve plate; Figure 3 for Figure 2 A magnified view of a section at point A in the middle; Figure 4 This is a schematic diagram of a streamlined rectifier valve plate structure. Figure 5 This is a schematic diagram of a U-shaped cross-section elastic metal ring structure.

[0025] The components include: 1. Valve body; 101. Left connecting flange; 102. Right connecting flange; 103. Valve body inlet air passage; 104. Valve body outlet air passage; 105. Valve body upper neck mounting sleeve; 106. Seal annular mounting groove; 2. Streamlined rectifier valve plate; 201. Valve plate airflow-facing arc surface; 202. Valve plate smooth guide back surface; 203. Valve plate mounting lug; 3. Valve stem; 4. Seal; 401. Seal inner wall contact surface; 5. U-shaped cross-section elastic metal ring; 6. Stuffing gland sealing assembly; 7. Guide bearing; 8. Valve position feedback unit; 9. Pneumatic actuator cylinder; 901. Actuator cylinder upper cover; 902. Actuator cylinder lower flange; 903. Cylinder inlet port; 904. Cylinder exhaust port; 10. Flexible buffer opening and closing module; 11. Miniature air pressure adaptive stabilizing module. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0027] like Figures 1 to 5As shown in the figure, this embodiment of the invention provides a low-disturbance, high-precision dedicated programmable valve adapted for oxygen separation using lithium-based molecular sieves. The specific structure, materials, operation method, and working principle of this embodiment will be described in detail below with reference to the accompanying drawings.

[0028] In this embodiment, the valve body 1 is entirely made of cast stainless steel. The valve body inlet air passage 103 and the valve body outlet air passage 104 are horizontal, straight, and equal-diameter channels, which converge and connect at the central cavity inside the valve body 1. A left connecting flange 101 and a right connecting flange 102 are integrally formed at the left and right ends of the valve body 1, respectively, for connection to external pipelines. A valve body upper neck mounting sleeve 105 is integrally formed on the upper wall of the valve body 1, and a sealing annular mounting groove 106 is provided at the junction of the inner wall of the valve body inlet air passage 103 and the central cavity.

[0029] The streamlined rectifier valve plate 2 is an asymmetrical streamlined rotating component made of stainless steel. Its outer peripheral wall and end faces have a circular arc transition of R1.5mm to R3mm at the junction, and the entire circumference is continuous without sharp corners or edges. The surface roughness Ra of the streamlined rectifier valve plate 2 is less than or equal to 0.4 micrometers after mechanical polishing, resulting in a mirror-like finish. The side of the streamlined rectifier valve plate 2 facing the valve body inlet air passage 103 is the valve plate airflow-facing arc surface 201, which has a full and convex arc shape; the side of the streamlined rectifier valve plate 2 facing the valve body outlet air passage 104 is the valve plate flow-guiding smooth back surface 202, which has a smooth transition shape, resulting in an overall asymmetrical streamlined configuration. A valve plate mounting lug 203 is fixedly provided on the valve plate flow-guiding smooth back surface 202 of the streamlined rectifier valve plate 2, and the valve plate mounting lug 203 is coaxially arranged with the valve body upper neck mounting cylinder 105.

[0030] The valve stem 3 is a long stainless steel shaft. Its lower end passes through the upper neck mounting sleeve 105 of the valve body and enters the interior of the valve body 1, where it is fixedly connected to the valve plate mounting lug 203. The upper end of the valve stem 3 extends out of the top of the upper neck mounting sleeve 105 of the valve body and enters the interior of the pneumatic actuator cylinder 9, where it is connected to the piston assembly for transmission.

[0031] A guide bearing 7 and a stuffing box sealing assembly 6 are sequentially arranged axially from bottom to top between the valve body upper neck mounting sleeve 105 and the valve stem 3. The guide bearing 7 is embedded in the inner wall of the valve body upper neck mounting sleeve 105, and has a gapless precision fit with the valve stem 3. The guide bearing 7 is made of self-lubricating wear-resistant material; in this embodiment, an oil-impregnated copper alloy material is selected, requiring no external lubrication. The stuffing box sealing assembly 6 is located above the guide bearing 7 and consists of flexible graphite sealing packing and a gland. It is used to seal the annular gap between the valve stem 3 and the valve body upper neck mounting sleeve 105, preventing gas inside the valve body 1 from leaking to the outside along the valve stem 3.

[0032] The seal 4 is embedded in the annular mounting groove 106. The overall outline of the seal 4 is annular, and its outer wall is fitted and fixed to the inner wall of the annular mounting groove 106. The surface of the seal 4 facing the outer peripheral wall of the streamlined rectifier valve plate 2 is the inner wall contact surface 401 of the seal. The inner wall contact surface 401 of the seal is a wear-resistant and low-friction composite layer. In this embodiment, a polytetrafluoroethylene composite layer is selected. The substrate of the seal 4 is an elastic material. In this embodiment, a polyurethane elastomer is selected. The substrate of the seal 4 and the inner wall contact surface 401 of the seal are bonded together by co-vulcanization. When the valve is closed, the inner wall contact surface 401 of the seal forms a full circumferential contact seal with the outer peripheral wall of the streamlined rectifier valve plate 2. When the valve is open, a small purge gap is maintained between the inner wall contact surface 401 and the outer peripheral wall of the streamlined rectifier valve plate 2. The sealing element 4 is embedded with a U-shaped cross-section elastic metal ring 5. The U-shaped cross-section elastic metal ring 5 is made of spring steel, and its opening is set towards the side of the valve body outlet air passage 104. The U-shaped cross-section elastic metal ring 5 is used to continuously press the inner wall contact surface 401 of the sealing element against the outer peripheral wall of the streamlined rectifier valve plate 2.

[0033] The pneumatic actuator cylinder 9 is fixedly mounted on the upper end of the valve body upper neck mounting cylinder 105 via the lower flange 902. The upper end of the pneumatic actuator cylinder 9 is equipped with an actuator cylinder cover 901. The side wall of the pneumatic actuator cylinder 9 is provided with a cylinder inlet port 903 and a cylinder exhaust port 904, used for the input and discharge of compressed air, respectively. A miniature air pressure adaptive stabilizing module 11 is installed upstream of the air supply pipeline of the pneumatic actuator cylinder 9. This module is a miniature precision pressure reducing valve used to compensate for pressure fluctuations in the industrial air source in real time, ensuring that the driving air pressure entering the pneumatic actuator cylinder 9 remains constant. A flexible buffer opening and closing module 10 is installed on the pneumatic actuator cylinder 9. Integrated inside the cylinder 9, this module features four independently adjustable damping parameters, causing the valve stem 3's speed curve under the actuator cylinder 9 to sequentially represent a slow pressure build-up phase, a uniform speed stabilization phase, a slow pressure relief phase, and a soft landing closing phase. The damping parameters for each phase are adjusted via independent throttle valves within the flexible buffer opening and closing module 10, allowing for the setting of speed and time for each phase according to the adsorption and desorption sequence requirements of the lithium-based molecular sieve. A valve position feedback unit 8 is fixedly installed on the outer rear wall of the pneumatic actuator cylinder 9. This unit is connected to the external main control system for real-time detection of the valve stem 3's position and feedback of the valve opening degree and opening / closing status signals to the main control system.

[0034] The operation process is as follows: When the external main control system issues an opening command, compressed air, after being stabilized by the micro pressure adaptive stabilizing module 11, enters the pneumatic actuator cylinder 9 through the cylinder inlet port 903, driving the valve stem 3 to move upward. In the initial stage of the valve stem 3's ascent, the flexible buffer opening and closing module 10 limits the air intake flow with the maximum damping parameter, causing the valve stem 3 to drive the streamlined rectifier valve plate 2 to rise slowly at an ultra-low speed. The tiny purge gap between the inner wall contact surface 401 of the seal and the outer peripheral wall of the streamlined rectifier valve plate 2 gradually widens, and the pressure in the valve body's air intake passage 103 is established smoothly without sudden pressure fluctuations. When the valve stem 3 enters the middle stroke, the flexible buffer opening and closing module 10 switches to a smaller damping parameter, causing the valve stem 3 to continue rising at a uniform speed, and the streamlined rectifier valve plate 2 quickly reaches the fully open position. In the fully open state, the streamlined rectifier valve plate 2 is suspended in the central cavity of the valve body 1. The airflow enters through the valve body inlet airflow channel 103 and is uniformly guided when it flows through the airflow-facing arc surface 201 of the streamlined rectifier valve plate 2. After being smoothly converged through the smooth back surface 202 of the valve plate, it is discharged from the valve body outlet airflow channel 104. There is no turbulence and micro-powder entrainment caused by sharp corner disturbances throughout the process.

[0035] When the external main control system issues a shutdown command, compressed air is discharged through the cylinder exhaust port 904, and the valve stem 3 moves downward under the action of the return spring inside the pneumatic actuator cylinder 9. The flexible buffer opening and closing module 10 limits the exhaust flow with gradually increasing damping parameters at the end of the valve stem 3's descent, causing the valve stem 3 speed to gradually decrease. At the final stage when the valve stem 3 reaches the end of its stroke, the flexible buffer opening and closing module 10 uses maximum damping parameters to allow the valve stem 3 to close at an extremely low speed. The outer peripheral wall of the streamlined rectifier valve plate 2 adheres to the inner wall contact surface 401 of the sealing element without impact, forming a full-circumferential contact seal. In the closed state, the U-shaped cross-section elastic metal ring 5 continuously presses the inner wall contact surface 401 of the sealing element against the outer peripheral wall of the streamlined rectifier valve plate 2, ensuring a tight seal at the sealing interface.

[0036] Under vacuum desorption conditions, a vacuum pump is connected to one side of the valve body outlet channel 104, which is under negative pressure. This negative pressure acts on the inner wall of the opening of the U-shaped cross-section elastic metal ring 5, causing the U-shaped cross-section elastic metal ring 5 to open further, enhancing its elastic compensation force on the inner wall contact surface 401 of the sealing element. The contact pressure between the inner wall contact surface 401 of the sealing element and the outer peripheral wall of the streamlined rectifier valve plate 2 increases with the increase of vacuum degree, forming a negative pressure self-locking sealing effect. In the high vacuum range, the inner wall contact surface 401 of the sealing element and the outer peripheral wall of the streamlined rectifier valve plate 2 are tightly fitted, maintaining a stable negative pressure in the tower and ensuring that the vacuum desorption of lithium-based molecular sieves is sufficient and thorough.

[0037] During long-term valve operation, when the inner wall contact surface 401 of the sealing element wears due to high-frequency opening and closing friction, the U-shaped cross-section elastic metal ring 5 continuously applies elastic force to ensure that the inner wall contact surface 401 of the sealing element is always in close contact with the outer peripheral wall of the streamlined rectifier valve plate 2, automatically compensating for the wear. Simultaneously, during each opening and closing of the valve, the minute purging gap between the inner wall contact surface 401 of the sealing element and the outer peripheral wall of the streamlined rectifier valve plate 2 changes. The airflow pressure difference on both sides of the valve plate blows away the lithium-based micropowder trapped at the sealing interface through this gap, preventing the micropowder from accumulating and compacting at the sealing interface.

[0038] During the reciprocating motion of the valve stem 3, the guide bearing 7 provides radial support to the valve stem 3, maintaining the coaxiality of the valve stem 3 and the upper neck mounting sleeve 105 of the valve body. The stuffing box seal assembly 6 forms a dynamic seal at the protrusion position of the valve stem 3, preventing gas leakage along the valve stem 3. The zero-clearance precision fit between the guide bearing 7 and the valve stem 3 ensures that the valve stem 3 maintains valve position accuracy over a long period of time when subjected to alternating high and low pressure impacts.

[0039] The valve position feedback unit 8 detects the position of the valve stem 3 in real time during the operation of the valve stem 3, and feeds back the valve opening degree and opening / closing status signal to the external main control system. The external main control system adjusts the timing according to the real-time valve position status to achieve closed-loop precise coupling of the timing of each process.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-disturbance, high-precision dedicated programmable valve for oxygen separation using lithium-based molecular sieves, comprising a valve body (1), a streamlined rectifier valve plate (2) disposed inside the valve body (1), a valve stem (3) connected to the streamlined rectifier valve plate (2), and a pneumatic actuator cylinder (9) disposed above the valve body (1) and drivenly connected to the valve stem (3), characterized in that: The pneumatic actuator cylinder (9) is provided with a flexible buffer opening and closing module (10) with four independent adjustable damping for making the valve opening and closing speed curve present as a slow start-up pressure building section, a uniform speed steady running section, a slow descent pressure relief section and a soft landing closing section.

2. The low-disturbance, high-precision dedicated programmable valve for oxygen separation adapted to lithium-based molecular sieves as described in claim 1, characterized in that: The outer peripheral wall of the streamlined rectifier valve plate (2) is provided with an arc transition at the junction of the two end faces. The surface of the streamlined rectifier valve plate (2) is a mirror polished surface. The side of the streamlined rectifier valve plate (2) facing the valve body inlet air passage (103) is the valve plate airflow-facing arc surface (201), and the side of the streamlined rectifier valve plate (2) facing the valve body outlet air passage (104) is the valve plate flow-guiding smooth back surface (202).

3. The low-disturbance, high-precision dedicated programmable valve for oxygen separation adapted to lithium-based molecular sieves as described in claim 1, characterized in that: The valve body (1) has an annular mounting groove (106) for sealing elements on the inner wall of the valve body inlet air passage (103). The annular mounting groove (106) is fitted with a sealing element (4) for forming a full circumferential contact seal with the outer peripheral wall of the streamlined rectifier valve plate (2). The surface of the sealing element (4) facing the streamlined rectifier valve plate (2) is the inner wall contact surface (401) of the sealing element. The sealing element (4) is fitted with a U-shaped cross-section elastic metal ring (5) for pressing the inner wall contact surface (401) of the sealing element against the outer peripheral wall of the streamlined rectifier valve plate (2). The opening of the U-shaped cross-section elastic metal ring (5) faces the valve body outlet air passage (104).

4. The low-disturbance, high-precision dedicated programmable valve for oxygen separation adapted to lithium-based molecular sieves according to claim 1, characterized in that: The valve body (1) has an upper neck mounting sleeve (105) on its upper wall. The valve stem (3) passes through the upper neck mounting sleeve (105). A guide bearing (7) for supporting the radial positioning of the valve stem (3) and a stuffing box sealing assembly (6) for sealing the gap between the valve stem (3) and the upper neck mounting sleeve (105) are provided between the upper neck mounting sleeve (105) and the valve stem (3).

5. The low-disturbance, high-precision dedicated programmable valve for oxygen separation adapted to lithium-based molecular sieves according to claim 1, characterized in that: The pneumatic actuator cylinder (9) is equipped with a valve position feedback unit (8) for real-time detection of the valve stem (3) position and feeding back the valve opening degree and opening / closing status signal to the main control system.

6. The low-disturbance, high-precision dedicated programmable valve for oxygen separation adapted to lithium-based molecular sieves according to claim 1, characterized in that: The pneumatic actuator cylinder (9) is equipped with a micro pressure adaptive stabilizing module (11) upstream of the air supply pipeline for real-time compensation of industrial air source pressure fluctuations to maintain constant valve drive air pressure.

7. The low-disturbance, high-precision dedicated programmable valve for oxygen separation adapted to lithium-based molecular sieves according to claim 3, characterized in that: The substrate of the seal (4) is an elastic material, and the inner wall contact surface (401) of the seal is a wear-resistant and low-friction composite layer. The substrate of the seal (4) and the inner wall contact surface (401) of the seal are integrated into one.

8. The low-disturbance, high-precision dedicated programmable valve for oxygen separation adapted to lithium-based molecular sieves according to claim 1, characterized in that: The streamlined rectifier valve plate (2) has a valve plate mounting lug (203) on its smooth back surface (202), and the lower end of the valve stem (3) is fixedly connected to the valve plate mounting lug (203).

9. The low-disturbance, high-precision dedicated programmable valve for oxygen separation adapted to lithium-based molecular sieves according to claim 1, characterized in that: The valve body (1) is provided with a left connecting flange (101) and a right connecting flange (102) at its left and right ends respectively. The upper end of the pneumatic actuator cylinder (9) is provided with an actuator cylinder cover (901). The lower end of the pneumatic actuator cylinder (9) is fixedly connected to the upper end of the valve body upper neck mounting cylinder (105) through the actuator cylinder lower flange (902). The side wall of the pneumatic actuator cylinder (9) is provided with a cylinder inlet port (903) and a cylinder exhaust port (904).

10. The low-disturbance, high-precision dedicated programmable valve for oxygen separation adapted to lithium-based molecular sieves according to claim 3, characterized in that: The sealing element annular mounting groove (106) is opened at the junction of the inner wall of the valve body inlet air passage (103) and the central cavity of the valve body (1). The sealing element (4) is embedded in the sealing element annular mounting groove (106). The inner wall contact surface (401) of the sealing element and the outer peripheral wall of the streamlined rectifier valve plate (2) form a full circumferential contact seal when the valve is closed, and a small purging gap is retained when the valve is open.

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