A low-opening-pressure ultrapure check valve

Abstract

This invention relates to the field of one-way valve technology, specifically to a low-opening-pressure ultrapure one-way valve, comprising a valve body, a first connecting sleeve, a second connecting sleeve, and further including a valve sleeve, a return spring, a drive assembly, a limit slider, a valve seat assembly, and a tension spring. The valve sleeve is connected to the valve body. Sealing rings are provided on the outer periphery of both the valve body and the valve sleeve. Threaded rings are integrally formed on both the end of the valve body and the end of the valve sleeve. An adjustment groove is provided on the inner periphery of the valve body, and a sliding groove extending to the inner side of the valve sleeve is provided inside the valve body. This invention solves the problem of one-way valves using ordinary thinner helical springs, where the helical spring undergoes radial twisting after repeated use, resulting in a reduction in the total length of the helical spring and preventing a tight fit between the valve disc and the valve body. This is achieved by setting different elastic coefficients for the front and rear sections of the return spring and designing the outer periphery of the return spring as a radial plane, ensuring that the return spring moves tightly against the inner wall of the valve sleeve after compression.

Description

Technical Field

[0001] This invention relates to the field of check valve technology, specifically to a low-opening-pressure ultrapure check valve. Background Technology

[0002] The working principle of a check valve is based on a key component inside the valve: the valve disc. When fluid flows in the correct direction, the valve disc is pushed open, allowing fluid to pass freely. However, when fluid attempts to flow backward, the valve disc closes, effectively preventing reverse flow. This working principle is based on fluid dynamics and pressure differentials. When the forward pressure is greater than the reverse pressure, the check valve opens, allowing fluid to pass; if the reverse pressure exceeds the forward pressure, the valve disc closes quickly to prevent unwanted flow.

[0003] In semiconductor manufacturing, the check valves used need to have good sealing performance to prevent contaminants from entering the high-purity working environment. Check valves that can open at low pressure can achieve instantaneous opening, effectively preventing contaminants from entering the valve body and fully ensuring the valve's sealing performance. Therefore, low-opening-pressure check valves are required in wet process equipment in the semiconductor industry.

[0004] In existing technologies, the return spring inside the valve is mostly a thin-diameter metal helical spring to ensure a low elastic coefficient and meet the requirement of low opening pressure. However, in actual production, it has been found that when using chemical solutions to remove particles, natural oxide layers, organic matter, metal contamination, sacrificial layers, polishing residues, etc., from the wafer manufacturing process, the large flow rate of the chemical solution requires it to flow through the check valve at a high pressure, resulting in a large valve disc travel distance. Because the traditional metal helical spring has a circular cross-section and a "line contact" with the inner wall of the valve body, the thin helical spring is easily rotated when the valve disc returns to its original position. After repeated use, the return spring will undergo radial distortion, which will compromise the sealing effect between the valve disc and the valve body after the valve disc returns to its original position. This allows contaminants to enter the check valve through the gap between the valve disc and the valve body, causing media contamination.

[0005] To address this, a low-opening-pressure ultrapure check valve is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a low-opening-pressure ultrapure check valve. By setting different elastic coefficients for the front and rear sections of the return spring and setting the outer periphery of the return spring as a radial plane, this invention ensures that the return spring moves tightly against the inner wall of the valve sleeve after compression. This solves the problem that in check valves using ordinary thinner helical springs, the helical spring undergoes radial twisting after repeated use, resulting in a reduction in the total length of the helical spring and making it impossible to ensure a tight fit between the valve disc and the valve body. This invention effectively ensures that the check valve can open at a lower pressure and effectively increases the fluid flow rate when the flow rate is large. At the same time, it significantly reduces the deformation distance of the return spring and avoids radial twisting of the return spring by moving the radial plane tightly against the inner wall of the valve sleeve, thus fully ensuring the sealing performance of the check valve.

[0007] To achieve the above objectives, the present invention provides a low-opening-pressure ultrapure one-way valve, comprising a valve body, a first connecting sleeve, a second connecting sleeve, and further comprising a valve sleeve, a return spring, a drive assembly, a limiting slider, a valve seat assembly, and a tension spring. The valve sleeve is connected to the valve body. Sealing rings are provided on the outer periphery of both the valve body and the valve sleeve. Threaded rings are integrally formed on the ends of both the valve body and the valve sleeve. An adjustment groove is formed on the inner periphery of the valve body, and a sliding groove extending to the inner side of the valve sleeve is formed inside the valve body. The return spring is disposed inside the valve sleeve. The drive assembly is installed in the sliding groove and is in contact with the outer periphery of the return spring. The limiting slider and the tension spring are both installed in the adjustment groove, and the drive assembly is in contact with the limiting slider. The tension spring is connected to the limiting slider. The valve seat assembly is slidably disposed between the valve body and the valve sleeve, and the end of the valve seat assembly is in contact with the inner wall of the valve body. When fluid pushes the valve seat assembly to compress the return spring to a set position, the drive assembly drives the limiting slider to move towards the valve body axis. The limiting slider applies pressure to the valve seat assembly, reducing the cross-section of the valve seat assembly end.

[0008] As described above, the return spring remains in contact with the inner wall of the valve body during extension and contraction, thus ensuring that the valve seat assembly moves only in a straight line along the inner wall of the valve body, preventing the valve seat assembly from flipping over and causing the one-way valve to fail. Furthermore, the valve body, valve sleeve, first connecting sleeve, second connecting sleeve, return spring, drive assembly, limit slider, and valve seat assembly are all made of ultra-pure PTFE as raw material and are manufactured through machining. PTFE has extremely low surface energy, making it difficult for other substances to adhere to its surface. When the medium used in the wet process equipment of the semiconductor industry passes through the valve body, the residue of the medium in the valve body can be minimized. Considering the material properties, during processing, the slotted parts are assembled by splicing. The appropriate shape is molded using powder, and then the parts are spliced ​​and sintered as a whole. The high viscosity of PTFE makes the corresponding components form a single unit.

[0009] Preferably, the reset spring includes a first spring body, a second spring body, and a radial plane. The first spring body and the second spring body are fixedly connected. The radial plane is constructed on the outer periphery of the first spring body and the second spring body. The first spring body is located on the side of the second spring body closer to the valve seat assembly, and the elastic coefficient of the first spring body is less than that of the second spring body. The end of the first spring body is in contact with the valve seat assembly, and the end of the second spring body is in contact with the inner wall of the valve sleeve.

[0010] Preferably, the valve seat assembly includes a limiting seat, a rod, a valve disc, a sliding plate, an anti-detachment plate, and a miniature spring. The limiting seat is slidably fitted to the inner circumference of the valve sleeve, and the side wall of the limiting seat is fitted to the end of the first spring body. The rod is inserted into the center of the limiting seat. The valve disc is installed at the end of the rod. The valve disc has multiple sliding grooves inside. The sliding plate extends into the sliding grooves. The anti-detachment plate is installed on the outer circumference of the sliding plate and is slidably fitted to the sliding groove. The miniature spring is installed in the sliding groove, and the end of the miniature spring abuts against the sliding plate.

[0011] Preferably, the limiting seat has multiple flow holes, and the multiple flow holes are distributed in a ring array about the insertion rod.

[0012] Preferably, the driving assembly includes an adhesive sheet, a vertical strip, and a horizontal strip. The adhesive sheet is attached to a radial plane at the center of the second spring body. The vertical strip is installed on the side of the adhesive sheet away from the second spring body. The horizontal strip is fixed to the end of the vertical strip and is slidably disposed in a sliding groove. The end of the horizontal strip is attached to the limiting slider.

[0013] Preferably, the limiting slider has a second inclined surface on the side near the corresponding horizontal bar, the horizontal bar has a first inclined surface at its end, and the limiting slider has a mating groove on its side wall.

[0014] Preferably, the valve disc is located inside the valve body, and the diameter of the valve disc is smaller than the diameter of the limiting seat.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. Under the action of the return spring, due to structural reasons, the one-way valve can only allow axial force, and the axial force cannot be too off-axis, otherwise other parts will be overturned or misaligned, thus causing the one-way valve to completely fail. The return spring maintains a clearance fit with the inner wall of the valve sleeve through the radial plane, and the movement trajectory of the return spring is further restricted by the drive assembly, thereby ensuring that the force on the return spring is neither off-axis nor too off-axis, thus avoiding the overturning or misalignment of other parts such as the valve disc, which would cause the one-way valve to completely fail. Repeated use can also ensure the sealing performance of the one-way valve. Furthermore, under the action of the first spring body and the second spring body with different elastic coefficients, the first spring body with a lower elastic coefficient allows the valve disc to be displaced and open the valve body when the fluid pressure is low. When the fluid pressure is high, the second spring body with a higher elastic coefficient has a smaller compression stroke, which can effectively reduce the movement stroke of the valve disc, thereby facilitating the rapid reset of the valve disc and ensuring the sealing performance of the one-way valve.

[0017] 2. Through the set drive component and limit slider, when the pressure of the chemical liquid is large and the second spring body is also compressed and deformed, the second spring body drives the drive component to move horizontally. With the help of the crossbar and the inclined surface of the docking groove, the limit slider moves towards the valve body axis. Then, after the valve disc is horizontally displaced, the sliding plate on its outer periphery moves towards the center of the valve disc due to the obstruction of the limit slider, thereby effectively increasing the flow cross-sectional area inside the valve body and improving the flow rate of the chemical liquid.

[0018] 3. Through the valve seat assembly, when the chemical liquid pressure is low, the valve disc travels a short distance and the sliding plate does not contact the limit slider. When the chemical liquid pressure is high, the valve disc travels a longer distance, and the limit slider moves towards the center of the valve disc. When the valve disc drives the sliding plate to contact the limit slider, the sliding plate slides towards the center of the valve disc due to the limiting effect of the horizontal bar. This increases the fluid flow cross-sectional area inside the valve body, allowing the chemical liquid to pass through quickly, thereby significantly improving the working efficiency of the check valve. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 This is an overall sectional view of the present invention;

[0021] Figure 3 This is a schematic diagram of the structure of the reset spring of the present invention;

[0022] Figure 4 This is a schematic diagram of the valve seat assembly of the present invention;

[0023] Figure 5 This is a cross-sectional view of the valve seat assembly of the present invention;

[0024] Figure 6 This is a cross-sectional view of the driving component of the present invention;

[0025] Figure 7 This is a cross-sectional view of the limiting slider and tension spring of the present invention;

[0026] Figure 8 This is a schematic diagram showing the connection between the drive component and the limiting slider of the present invention.

[0027] In the diagram: 1. Valve body; 2. Valve sleeve; 3. First connecting sleeve; 4. Second connecting sleeve; 5. Return spring; 51. First spring body; 52. Second spring body; 53. Radial plane; 6. Drive assembly; 61. Adhesive piece; 62. Vertical bar; 63. Horizontal bar; 631. First inclined surface; 7. Limiting slider; 71. Second inclined surface; 72. Connecting groove; 8. Valve seat assembly; 81. Limiting seat; 811. Flow hole; 82. Insert rod; 83. Valve disc; 831. Slide groove; 84. Sliding piece; 85. Anti-detachment piece; 86. Miniature spring; 9. Tension spring; 11. Sealing ring; 12. Threaded ring; 13. Adjusting groove; 14. Sliding groove. Detailed Implementation

[0028] 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.

[0029] Please see Figures 1 to 8 This invention provides a low-opening-pressure ultrapure check valve, the technical solution of which is as follows:

[0030] A low-opening-pressure ultrapure check valve includes a valve body 1, a first connecting sleeve 3, a second connecting sleeve 4, a valve sleeve 2, a return spring 5, a drive assembly 6, a limit slider 7, a valve seat assembly 8, and a tension spring 9. The valve sleeve 2 is connected to the valve body 1. The first connecting sleeve 3 and the second connecting sleeve 4 are respectively connected to the ends of the valve body 1 and the valve sleeve 2. The first connecting sleeve 3 and the second connecting sleeve 4 are used to connect to external fluid pipelines. Sealing rings 11 are provided on the outer periphery of both the valve body 1 and the valve sleeve 2. The sealing rings 11 are used to ensure a tight seal between the valve body 1 and the first connecting sleeve 3. The valve body 1 and valve sleeve 2 are sealed, and the valve body 1 and valve sleeve 2 are integrally formed with threaded rings 12. The valve body 1 and valve sleeve 2 are connected to the first connecting sleeve 3 and the second connecting sleeve 4 respectively through the threaded rings 12. The valve body 1 has an adjusting groove 13 on its inner circumference, and the valve body 1 has a sliding groove 14 extending to the inner side of the valve sleeve 2. The two ends of the sliding groove 14 are located inside the valve body 1 and inside the valve sleeve 2 respectively. The return spring 5 is set inside the valve sleeve 2. In the static state, the end of the return spring 5 is installed on the sliding groove 14. The drive assembly 6 is installed on the sliding groove 14. Within the moving groove 14, the drive assembly 6 is in contact with the outer periphery of the return spring 5. When the return spring 5 deforms to a certain length, it will drive the drive assembly 6 to translate. Simultaneously, since the drive assembly 6 can only move along the axis of the valve body 1, it restricts the movement trajectory of the return spring 5, preventing axial deflection. The limit slider 7 and tension spring 9 are both installed within the adjusting groove 13, with the drive assembly 6 in contact with the limit slider 7. The tension spring 9 is located deep within the adjusting groove 13 and connected to the limit slider 7. When the drive assembly 6 deforms with the return spring 5... When the displacement occurs, it will drive the limit slider 7 to perform the corresponding action. The valve seat assembly 8 is slidably disposed between the valve body 1 and the valve sleeve 2, and the end of the valve seat assembly 8 is in contact with the inner wall of the valve body 1. When the fluid pushes the valve seat assembly 8 to squeeze the return spring 5 to the set position, the drive assembly 6 drives the limit slider 7 to move towards the axis of the valve body 1. At this time, the valve seat assembly 8 will produce a displacement of the same magnitude as the deformation length of the return spring 5 due to the action of the fluid. Therefore, the valve seat assembly 8 will contact the limit slider 7. The limit slider 7 applies pressure to the valve seat assembly 8 to reduce the cross section of the end of the valve seat assembly 8.

[0031] Reference Figure 2 and Figure 3In one embodiment of the present invention, specifically, the reset spring 5 includes a first spring body 51, a second spring body 52, and a radial plane 53. The first spring body 51 and the second spring body 52 are fixedly connected. The radial plane 53 is constructed on the outer periphery of the first spring body 51 and the second spring body 52. ​​The first spring body 51 is located on the side of the second spring body 52 closer to the valve seat assembly 8, and the elastic coefficient of the first spring body 51 is smaller than that of the second spring body 52. ​​Both the first spring body 51 and the second spring body 52 are made of ultra-pure PTFE material, and the elastic coefficient of the first spring body 51 is smaller than that of the second spring body 52. ​​The end of the first spring body 51 is in contact with the valve seat assembly 8, and the second spring body 52 is in contact with the valve seat assembly 8. The end of spring 52 fits against the inner wall of the valve sleeve 2. When the valve seat assembly 8 undergoes slight displacement, the first spring 51 deforms while the second spring 52 does not deform, thus ensuring that the check valve can open at a lower pressure. When the fluid pressure is high, the valve seat assembly 8 will undergo a large displacement, causing the second spring 52 to also deform. Compared with the return spring 5 which uses a smaller elastic coefficient, the displacement distance of the valve seat assembly 8 can be reduced under the action of the second spring 52, which is conducive to the valve seat assembly 8 quickly resetting and closing the valve body 1. The radial plane 53 is clearance-fitted with the inner wall of the valve sleeve 2 to ensure that the force does not deviate from the axis, thereby preventing the valve disc 83 from flipping or misaligning and causing the check valve to completely fail.

[0032] Reference Figure 4 and Figure 5 In one embodiment of the present invention, the valve seat assembly 8 specifically includes a limiting seat 81, a rod 82, a valve disc 83, a sliding plate 84, an anti-detachment plate 85, and a miniature spring 86. The limiting seat 81 is slidably fitted to the inner circumference of the valve sleeve 2, and the side wall of the limiting seat 81 is fitted to the end of the first spring body 51. The rod 82 is inserted into the center of the limiting seat 81. The valve disc 83 is installed at the end of the rod 82. A plurality of sliding grooves 831 are formed inside the valve disc 83. The sliding plate 84 extends into the sliding grooves 831. The anti-detachment plate 85 is installed on the outer circumference of the sliding plate 84, and the anti-detachment plate 85 is slidably fitted to the sliding grooves 831. The miniature spring 86 is installed in the sliding groove. Inside 831, and with the end of the miniature spring 86 abutting against the sliding plate 84, when the pressure applied by the fluid to the valve disc 83 is transmitted to the first spring body 51 through the limiting seat 81, the first spring body 51 will first undergo compression deformation due to its small elastic coefficient. Then, the limiting seat 81 and the valve disc 83 will move together. The fluid enters the valve body 1 and the valve sleeve 2 through the gap between the outer periphery of the valve disc 83 and the valve body 1. The limiting seat 81 has multiple flow holes 811, and the multiple flow holes 811 are arranged in a ring array about the insert rod 82. The fluid entering the valve sleeve 2 passes through the flow holes 811 and flows out from the one-way valve.

[0033] Reference Figure 6 and Figure 8As one embodiment of the present invention, specifically, the driving component 6 includes a bonding piece 61, a vertical strip 62, and a horizontal strip 63. The bonding piece 61 is bonded to the radial plane 53 at the center of the second spring body 52. ​​When the second spring body 52 deforms, it will drive the bonding piece 61 to move together. The vertical strip 62 is installed on the side of the bonding piece 61 away from the second spring body 52. ​​The horizontal strip 63 is fixed to the end of the vertical strip 62 and is slidably disposed in the sliding groove 14. The end of the horizontal strip 63 is bonded to the limiting slider 7. When the bonding piece 61 moves with the second spring body 52, the vertical strip 62 and the horizontal strip 63 move together with the bonding piece 61 toward the end of the valve sleeve 2 away from the valve body 1. The horizontal strip 63 moves toward the limiting slider 7. Through the cooperation of the first inclined surface 631 and the second inclined surface 71, the end of the horizontal strip 63 is inserted into the docking groove 72 of the limiting slider 7.

[0034] Reference Figure 7 and Figure 8 As one embodiment of the present invention, specifically, the limiting slider 7 has a second inclined surface 71 on the side near the corresponding horizontal bar 63, a first inclined surface 631 is provided at the end of the horizontal bar 63, and a docking groove 72 is provided on the side wall of the limiting slider 7; when the second spring body 52 deforms, it means that the valve disc 83 reaches the set stroke value. At this time, the movement trajectory of the limiting slider 7 and the sliding piece 84 coincides. When the edge of the sliding piece 84 contacts the limiting slider 7, under the action of the second inclined surface 71 on the side wall of the limiting slider 7 and the first inclined surface 631 at the end of the horizontal bar 63, the end of the horizontal bar 63 is guided to insert into the docking groove 72, thereby causing the limiting slider 7 to protrude from the inner wall of the valve body 1. After the sliding piece 84 contacts the limiting slider 7, it moves towards the center of the valve disc 83, thereby squeezing the micro spring 86, and by squeezing the sliding piece 84 into the inner side of the valve disc 83, the fluid passage cross-sectional area of ​​the valve body 1 is increased.

[0035] Reference Figure 2 and Figure 5 In one embodiment of the present invention, specifically, the valve disc 83 is located inside the valve body 1, and the diameter of the valve disc 83 is smaller than the diameter of the limiting seat 81. When the valve disc 83 separates from the inner wall of the valve body 1, both the valve body 1 and the valve sleeve 2 are in an open state. When the sliding plate 84 moves towards the center of the valve disc 83 due to the action of the limiting slider 7, the sliding plate 84 separates from the inner wall of the valve body 1, thereby further increasing the fluid flow cross-sectional area of ​​the valve body 1.

[0036] Working principle: Since the elastic coefficients of the first spring body 51 and the second spring body 52 are different, and the first spring body 51 with the smaller elastic coefficient is set close to the side of the valve body 1, when the fluid pressure is small, the first spring body 51 deforms while the second spring body 52 does not deform. At this time, the valve disc 83 separates from the inner wall of the valve body 1. The fluid passes through the gap between the valve disc 83 and the valve body 1, passes through the flow hole 811 and enters the valve sleeve 2, and then flows out from the end of the valve sleeve 2.

[0037] When the fluid pressure is high and the first spring 51 reaches its maximum deformation value, the second spring 52 gradually deforms. When the second spring 52 is in a compressed state, the valve disc 83 separates from the inner wall of the valve body 1. The second spring 52 drives the bonding piece 61 to move towards the valve sleeve 2 away from the valve body 1. The vertical bar 62 and the horizontal bar 63 move towards the valve sleeve 2 away from the valve body 1 along with the bonding piece 61. With the cooperation of the first inclined surface 631 and the second inclined surface 71, the end of the horizontal bar 63 slowly inserts into the docking groove 72, so that the limiting slider 7 moves towards the center of the valve disc 83.

[0038] When the second spring 52 deforms, the valve disc 83 displacement reaches the set stroke value, which means that the movement trajectory of the limit slider 7 and the sliding piece 84 coincides. When the edge of the sliding piece 84 contacts the limit slider 7, the limit slider 7 pushes the sliding piece 84 to move towards the center of the valve disc 83. The miniature spring 86 is in a compressed state. The larger the area of ​​the sliding piece 84 entering the valve disc 83, the larger the cross-sectional area through which the fluid passes in the valve body 1.

[0039] When the fluid has finished passing through, the fluid pressure has gradually decreased. The second spring body 52 first resets, and through the bonding piece 61, it drives the vertical bar 62 and the horizontal bar 63 to reset. The tension spring 9 pulls the limit slider 7 to reset. When the first spring body 51 resets, the radial plane 53 is in clearance fit with the inner wall of the valve sleeve 2 to prevent the valve disc 83 from flipping or misaligning and causing the one-way valve to completely fail.

[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-opening-pressure ultrapure check valve, comprising a valve body (1), a first connecting sleeve (3), and a second connecting sleeve (4), characterized in that: It also includes a valve sleeve (2), a return spring (5), a drive assembly (6), a limit slider (7), a valve seat assembly (8), and a tension spring (9). The valve sleeve (2) is connected to the valve body (1). A sealing ring (11) is provided on the outer periphery of both the valve body (1) and the valve sleeve (2). A threaded ring (12) is integrally formed on the end of the valve body (1) and the end of the valve sleeve (2). An adjustment groove (13) is provided on the inner periphery of the valve body (1), and a sliding groove (14) extending to the inner side of the valve sleeve (2) is provided inside the valve body (1). The return spring (5) is located inside the valve sleeve (2). The drive assembly (6) is installed in the sliding groove (14), and the drive assembly (6) is... The limit slider (7) and tension spring (9) are both installed in the adjustment groove (13), and the drive assembly (6) is in contact with the limit slider (7). The tension spring (9) is connected to the limit slider (7). The valve seat assembly (8) is slidably disposed between the valve body (1) and the valve sleeve (2), and the end of the valve seat assembly (8) is in contact with the inner wall of the valve body (1). When the fluid pushes the valve seat assembly (8) to squeeze the return spring (5) to the set position, the drive assembly (6) drives the limit slider (7) to move towards the axis of the valve body (1). The limit slider (7) applies pressure to the valve seat assembly (8) to reduce the cross section of the end of the valve seat assembly (8).

2. The low opening pressure ultrapure check valve according to claim 1, characterized in that: The reset spring (5) includes a first spring body (51), a second spring body (52), and a radial plane (53). The first spring body (51) and the second spring body (52) are fixedly connected. The radial plane (53) is constructed on the outer periphery of the first spring body (51) and the second spring body (52). The first spring body (51) is located on the side of the second spring body (52) closer to the valve seat assembly (8). The elastic coefficient of the first spring body (51) is smaller than that of the second spring body (52). The end of the first spring body (51) is in contact with the valve seat assembly (8), and the end of the second spring body (52) is in contact with the inner wall of the valve sleeve (2).

3. The low opening pressure ultrapure check valve according to claim 2, characterized in that: The valve seat assembly (8) includes a limiting seat (81), a rod (82), a valve disc (83), a sliding plate (84), an anti-detachment plate (85), and a miniature spring (86). The limiting seat (81) is slidably fitted to the inner circumference of the valve sleeve (2), and the side wall of the limiting seat (81) is fitted to the end of the first spring body (51). The rod (82) is inserted into the center of the limiting seat (81). The valve disc (83) is installed at the end of the rod (82). The valve disc (83) has multiple sliding grooves (831) inside. The sliding plate (84) extends into the sliding groove (831). The anti-detachment plate (85) is installed on the outer circumference of the sliding plate (84), and the anti-detachment plate (85) is slidably fitted to the sliding groove (831). The miniature spring (86) is installed in the sliding groove (831), and the end of the miniature spring (86) abuts against the sliding plate (84).

4. The low opening pressure ultrapure check valve according to claim 3, characterized in that: The limiting seat (81) has multiple flow holes (811), and the multiple flow holes (811) are arranged in a ring array about the insertion rod (82).

5. The low opening pressure ultrapure check valve according to claim 4, characterized in that: The drive assembly (6) includes a bonding piece (61), a vertical strip (62), and a horizontal strip (63). The bonding piece (61) is bonded to the radial plane (53) at the center of the second spring body (52). The vertical strip (62) is installed on the side of the bonding piece (61) away from the second spring body (52). The horizontal strip (63) is fixed to the end of the vertical strip (62) and is slidably disposed in the sliding groove (14). The end of the horizontal strip (63) is bonded to the limiting slider (7).

6. The low opening pressure ultrapure check valve according to claim 4, characterized in that: The limiting slider (7) has a second inclined surface (71) on the side near the corresponding horizontal bar (63), the end of the horizontal bar (63) has a first inclined surface (631), and the side wall of the limiting slider (7) has a docking groove (72).

7. The low opening pressure ultrapure check valve according to claim 4, characterized in that: The valve disc (83) is located inside the valve body (1), and the diameter of the valve disc (83) is smaller than the diameter of the limiting seat (81).

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