Pressure release valve

Abstract

The utility model relates to the technical field of hemodialysis equipment, in particular to a pressure release valve, which comprises an upper valve body and a lower valve body, a pressure pad and a sealing membrane at the bottom of the pressure pad are pressed in a cavity between the upper valve body and the lower valve body, the sealing membrane divides the cavity into an upper cavity and a lower cavity, an adjusting knob is arranged at the top of the upper valve body, and the adjusting knob is arranged at the bottom of the lower valve body. An adjusting thread pair connected with the adjusting knob is arranged in the upper cavity, a through hole is formed in the middle of the pressing pad, a pressing block is arranged in the through hole, and an elastic body is arranged between the pressing block and the adjusting thread pair; a water outlet valve opening is formed in the lower cavity; under the extrusion of the elastic piece, the middle part of the bottom of the pressing block abuts against the middle part of the sealing membrane to seal the water outlet valve port, and a gap is formed between the edge of the bottom of the pressing block and the sealing membrane; when liquid enters the pressure release valve, the liquid can change the volume of the cavity of the pressure release valve due to the upward movement of the sealing membrane, then the pressure at the front end of the pressure release valve is self-adjusted, and meanwhile, the problem that the pressure release valve generates squeal during working can be solved.

Description

Technical Field

[0001] This utility model relates to the field of hemodialysis equipment technology, and in particular to a pressure relief valve. Background Technology

[0002] The pressure relief valve of the water circuit system in a hemodialysis machine is a key component to ensure stable system pressure. Based on the pressure it regulates, it can be divided into high-pressure and low-pressure types. When the water circuit system pressure exceeds the calibrated range, the pressure relief valve automatically activates to release fluid, maintaining the stability of the water circuit system. By opening and closing the pressure relief valve, pressure fluctuations caused by changes in flow rate are buffered, preventing pipe rupture, pump overload, or deformation of the balance chamber diaphragm.

[0003] The pressure relief valve has a balancing chamber and a dialysate mixing system at its front end. In the existing technology, because the pressure relief valve block is tightly fitted to the sealing diaphragm, when liquid enters the pressure relief valve, the sealing diaphragm is directly pressed against the block. When the inlet pressure changes, the sealing diaphragm has no room to move, resulting in a large deviation between the pressure value at the front end of the pressure relief valve and the valve's calibrated pressure. When the pressure is low at low dialysate flow rates, the pressure balance of the front-end water circuit system cannot be guaranteed, leading to problems such as the dialysate mixing system's conductivity not being balanced or the dry powder cartridge not being filled. When the pressure is high at high dialysate flow rates, the pressure is too high, and the balancing chamber cannot correctly perform its liquid balancing function, resulting in a mismatch between the dialysate and waste liquid flow rates. Utility Model Content

[0004] To address the problem in existing technologies where the pressure at the front end of a pressure relief valve deviates significantly from the pressure calibrated at the rated flow rate under high or low flow conditions, this invention provides a pressure relief valve that can self-regulate the pressure at the front end, thus helping to ensure pressure balance in the upstream water system.

[0005] To achieve the above objectives, the following technical solutions are provided:

[0006] A pressure relief valve includes an upper valve body and a lower valve body. A pressure pad and a sealing diaphragm at the bottom of the pressure pad are press-fitted into a cavity between the upper and lower valve bodies. The sealing diaphragm divides the cavity into an upper cavity and a lower cavity. An adjustment knob is provided on the top of the upper valve body. An adjustment threaded pair connected to the adjustment knob is provided in the upper cavity. A through hole is provided in the middle of the pressure pad. A pressure block is provided in the through hole. An elastic body is connected between the pressure block and the adjustment threaded pair. A water outlet is provided in the lower cavity. Under the compression of the elastic body, the middle part of the bottom of the pressure block abuts against the middle part of the sealing diaphragm to close the water outlet. A gap is provided between the bottom edge of the pressure block and the sealing diaphragm.

[0007] Furthermore, the gap between the outer side of the pressure block and the sealing diaphragm is 0.1mm-0.3mm.

[0008] Furthermore, the compressibility of the elastomer is 10%-25%.

[0009] Furthermore, the contact area between the pressure block and the sealing diaphragm is 70%-80% of the sealing diaphragm area.

[0010] Furthermore, the upper and lower edges of the sealing diaphragm are provided with annular protrusions, and the bottom edge of the pressure pad is provided with annular grooves that match the annular protrusions.

[0011] The beneficial effects of this utility model are as follows:

[0012] 1. By setting a gap between the outer side of the pressure block and the sealing diaphragm, the sealing diaphragm is allowed to move upward. When liquid enters the pressure relief valve, the liquid can change the volume of the pressure relief valve cavity due to the upward movement of the sealing diaphragm, thereby self-regulating the pressure at the front end of the pressure relief valve. This can solve the problem of large deviation between the pressure value at the front end of the pressure relief valve and the pressure calibrated at the rated flow rate when the flow rate is high or low.

[0013] 2. On the one hand, by increasing the contact area between the pressure block and the sealing diaphragm, the vibration of the sealing diaphragm when the pressure relief valve is filled with liquid is reduced. On the other hand, by increasing the stiffness of the elastic body and changing the natural frequency of the elastic body, the resonance phenomenon of the sealing diaphragm, elastic body and adjusting thread pair when the pressure relief valve is filled with liquid within the rated pressure range is solved, thereby avoiding the whistling sound of the pressure relief valve during operation. Attached Figure Description

[0014] Appendix Figure 1 This is an overall structural diagram of the pressure relief valve of this utility model;

[0015] Appendix Figure 2 for Figure 1 A sectional view;

[0016] Appendix Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0017] Appendix Figure 4 for Figure 1 An explosion diagram;

[0018] In the diagram: 1. Upper valve body; 2. Lower valve body; 3. Pressure pad; 4. Sealing diaphragm; 5. Adjusting knob; 6. Adjusting threaded pair; 7. Pressure block; 8. Elastomer; 9. Water outlet valve port; 10. Gap; 11. Annular protrusion; 12. Annular groove. Detailed Implementation

[0019] The following detailed description of a pressure relief valve according to the present invention is based on specific embodiments.

[0020] like Figure 1 , Figure 2 , Figure 3 , Figure 4As shown, a pressure relief valve includes an upper valve body 1 and a lower valve body 2. A pressure pad 3 and a sealing diaphragm 4 at the bottom of the pressure pad 3 are press-fitted into the cavity between the upper valve body 1 and the lower valve body 2. The sealing diaphragm 4 divides the cavity into an upper cavity and a lower cavity. An adjustment knob 5 is provided on the top of the upper valve body 1. An adjustment threaded pair 6 connected to the adjustment knob 5 is provided in the upper cavity. A through hole is provided in the middle of the pressure pad 3. A pressure block 7 is provided in the through hole. An elastic body 8 is provided between the pressure block 7 and the adjustment threaded pair 6. A water outlet 9 is provided in the lower cavity. Under the compression of the elastic body 8, the middle part of the bottom of the pressure block 7 abuts against the middle part of the sealing diaphragm 4 to close the water outlet 9. A gap 10 is provided between the bottom edge of the pressure block 7 and the sealing diaphragm 4.

[0021] In this embodiment, as Figure 2 As shown in the diagram, the arrow points in the direction of liquid inlet. When the water system pressure is too high, the internal pressure of the lower inlet chamber pushes the sealing diaphragm upward, connecting the left inlet chamber of the pressure relief valve with the outlet valve. Liquid is then discharged from the outlet valve and the outlet channel, thus relieving pressure. The upper valve body 1 and the lower valve body 2 are connected by threads. When the upper valve body 1 is screwed on, the support on the inner wall edge of the upper valve body 1 presses down on the pressure pad 3 and tightens the sealing diaphragm 4, dividing the internal cavity of the pressure relief valve into a non-flowing upper and lower cavity. The adjusting threaded pair 6 consists of an adjusting nut with internal threads and an adjusting screw with external threads. After the adjusting nut and the adjusting screw are threaded together, a limit block is installed at the bottom of the adjusting screw to prevent the adjusting nut from unscrewing when adjusting the pressure. The adjusting knob 5 is fastened to the top of the upper valve body 1, and the internal part of the adjusting knob 5 is fixedly connected to the adjusting nut. Pulling up the adjusting knob 5 allows it to rotate and drive the adjusting screw to rotate. The pressure block 7 is placed on the upper part of the sealing diaphragm 4. The upper and lower edges of the sealing diaphragm 4 are provided with annular protrusions 11, and the bottom edge of the pressure pad 3 is provided with annular grooves 12 that match the annular protrusions 11. The annular grooves 12 on the lower end face of the pressure block 7 cooperate with the annular protrusions 11 on the upper end face of the sealing diaphragm 4 to prevent the pressure block 7 from moving on the sealing diaphragm 4.

[0022] Furthermore, in existing dialysis equipment, during treatment or cleaning and disinfection, the pressure relief valve experiences a sudden pressure drop during fluid inlet due to the high-speed fluid passing through the narrow valve orifice. This causes the valve assembly's natural frequency to couple with the fluid pulsation frequency, easily generating a whistling sound. The lower inner hole of the elastic body 8 mates with the pressure block 7, and the upper inner hole of the elastic body 8 mates with the adjusting thread pair 6. The length of the elastic body 8 can vary depending on the engagement position of the adjusting nut. By replacing the elastic body 8 with different force values, the pressure relief valve can achieve graded and segmented pressure adjustment. This solution increases the stiffness of the elastic body 8 and changes its natural frequency, resolving the resonance phenomenon that occurs when the sealing diaphragm 4, elastic body 8, and adjusting thread pair 6 are introduced into the pressure relief valve within the rated operating pressure range, thereby avoiding the whistling sound during operation. At the rated operating pressure of the pressure relief valve, the compression rate of the elastic body 8 is 10%-25%. The compression rate refers to the percentage reduction in length of the elastic body 8 under constant pressure. In this embodiment, the elastic body 8 is a spring.

[0023] In this embodiment, as Figure 3 As shown, the gap 10 between the outer side of the pressure block 7 and the sealing diaphragm 4 is 0.1mm-0.3mm. After the pressure relief valve is calibrated at the rated flow rate, the gap 10 between the sealing diaphragm 4 and the outlet valve 9 remains constant and will not be adjusted according to the flow rate at the inlet. That is, when the outlet valve 9 of the pressure relief valve is fixed, the pressure at the front end of the pressure relief valve will change with the change of the inlet flow rate (a large inlet flow rate results in a large pressure at the front end of the pressure relief valve, and a small inlet flow rate results in a small pressure at the front end of the pressure relief valve). In the prior art, when there is no gap 10 between the outer side of the pressure block 7 and the sealing diaphragm 4, the pressure relief valve is inlet, and the sealing diaphragm 4 is directly attached to the pressure block 7. When the inlet pressure changes, the sealing diaphragm 4 has no upward movement space.

[0024] This design reserves a specific gap 10 between the outer side of the pressure block 7 and the sealing diaphragm 4. When the pressure relief valve is filled with liquid, it can adjust the pressure at the front end of the pressure relief valve by changing the size of the pressure relief valve cavity. This can solve the problem of large deviation between the pressure value at the front end of the pressure relief valve and the pressure calibrated at the rated flow rate when the pressure relief valve is at high or low flow rates. This is beneficial to ensuring the pressure balance of the front-end water circuit system. At the same time, the reserved specific gap 10 can also limit the upward movement distance of the sealing diaphragm and avoid the resonance phenomenon of the sealing diaphragm 4 when liquid is filled. When the dialysate flow rate is low, the inlet pressure is also low. During inlet, the sealing diaphragm 4 moves upward into the upper movable space. The specific gap 10 can appropriately increase the volume of the lower chamber for inlet. With a fixed outlet, this creates a situation where the inlet volume is greater than the outlet volume, ensuring that the pressure of the front-end liquid system remains above 40 kPa. This guarantees the proper balance of the dialysate mixing system's conductivity or the sequential filling of the dry powder cartridge. When the dialysate flow rate is high, the inlet pressure is also high. During inlet, the sealing diaphragm 4 moves upward into the upper movable space. The specific gap 10 can appropriately increase the volume of the lower chamber for inlet. Continuous inlet can create local high pressure and make the outlet larger than the rated flow rate, ensuring that the pressure of the front-end liquid system remains below 60 kPa. This ensures that the balance chamber can correctly perform its liquid balance function, balancing the flow rates of dialysate and waste liquid. It can also change the amplitude and frequency of the sealing diaphragm 4, avoiding resonance phenomena in the sealing diaphragm.

[0025] In this design, the contact area between the pressure block 7 and the sealing diaphragm 4 is 70%-80% of the sealing diaphragm 4. By increasing the contact area between the pressure block 7 and the sealing diaphragm 4, the vibration of the sealing diaphragm 4 when the pressure relief valve is filled with liquid is reduced, thereby avoiding whistling during operation.

Claims

1. A pressure relief valve characterized by, The utility model provides a valve body, including upper valve body (1) and lower valve body (2), the cavity pressure is equipped with pressure pad (3) and the sealing diaphragm (4) of pressure pad (3) bottom between upper valve body (1) and lower valve body (2), and the sealing diaphragm (4) divides the cavity into upper cavity and lower cavity, the top of upper valve body (1) is equipped with adjusting knob (5), is equipped with adjusting screw pair (6) with adjusting knob (5) in upper cavity, the middle part of pressure pad (3) is equipped with through -hole, is equipped with pressure block (7) in through -hole, and the elastic body (8) is connected between pressure block (7) and adjusting screw pair (6);Lower cavity is equipped with water outlet valve mouth (9);Under the extrusion of elastic body (8), the middle part of the bottom of pressure block (7) and the middle part of sealing diaphragm (4) abut, and water outlet valve mouth (9) is closed, and the clearance (10) between the bottom edge of pressure block (7) and sealing diaphragm (4) is equipped.

2. The pressure relief valve of claim 1, wherein The clearance (10) between the outer side of pressure block (7) and sealing diaphragm (4) is 0.1mm-0.3mm.

3. The pressure relief valve according to claim 1 or 2, wherein The compression rate of elastic body (8) is 10%-25%.

4. The pressure relief valve of claim 1 or 2, wherein The contact area of pressure block (7) and sealing diaphragm (4) is 70%-80% of sealing diaphragm (4).

5. The pressure relief valve of claim 3, wherein The contact area of pressure block (7) and sealing diaphragm (4) is 70%-80% of sealing diaphragm (4).

6. The pressure relief valve of claim 1, 2, or 5, wherein, The upper and lower side edges of sealing diaphragm (4) are equipped with annular protrusions (11), and the bottom edge of pressure pad (3) is equipped with annular grooves (12) matched with the annular protrusions (11).

7. The pressure relief valve of claim 3, wherein The upper and lower side edges of sealing diaphragm (4) are equipped with annular protrusions (11), and the bottom edge of pressure pad (3) is equipped with annular grooves (12) matched with the annular protrusions (11).

8. The pressure relief valve of claim 4, wherein The upper and lower side edges of sealing diaphragm (4) are equipped with annular protrusions (11), and the bottom edge of pressure pad (3) is equipped with annular grooves (12) matched with the annular protrusions (11).

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