A negative pressure driven normally closed pinch valve

Abstract

The application discloses a negative pressure driving type normally closed pinch valve, which comprises a valve body, a valve cavity is arranged in the valve body, a tubular valve component and a plunger element are arranged in the valve cavity, a valve sleeve is arranged on the valve body, an annular air cavity is arranged in the valve sleeve, a negative pressure port and a pressure relief port are arranged at two ends of the valve body, a tension piston is threadedly connected to one end of the transmission sleeve which faces the negative pressure port, a pushing part is arranged at the other end of the transmission sleeve which faces the pressure relief port, the valve body is provided with a step, a compression spring is arranged between the transmission sleeve and the step, a sealing connecting piece is arranged between the tension piston and the end surface of the valve body, and the sealing connecting piece comprises a rigid connecting sleeve and a flexible bellows sleeve. The sealing connection between the rigid connecting sleeve and the flexible bellows sleeve, the sealing connection between the rigid connecting sleeve and the tension piston and the sealing connection between the flexible bellows sleeve and the valve body eliminate the gap between the tension piston and the valve body, and the stability and reliability of the transmission sleeve in operation are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pinch valves, in particular to a negative pressure driven normally closed pinch valve. BACKGROUND

[0002] A pinch valve is a valve that opens and closes a fluid passageway by applying an external clamping action to a flexible tubular valve member connected between two pipe fittings. In the open state, the tubular valve member remains unobstructed, allowing fluid to pass through. In the closed state, the clamping device externally compresses the flexible peripheral wall of the valve member, causing it to deform and close the internal flow passage to block the fluid.

[0003] However, in the prior art, during the closing process of the valve, the tubular valve member is subjected to strong mechanical clamping action, resulting in significant local wear. This problem is particularly prominent when the plunger or support contact profile of the clamping device directly impacts or repeatedly rubs against the outer wall of the valve body. Not only does this shorten the service life of the valve body, but it can also lead to a decrease in sealing performance, leakage, and even sudden failure.

[0004] Currently, a Chinese invention patent application (publication number CN108223831A) discloses a pinch valve, which includes a valve member that defines a flow passage for fluid as a tubular component. The tubular valve member is arranged between two connecting elements and includes a flexible peripheral wall. The pinch valve includes a clamping device arranged externally to the peripheral wall and designed to be able to switch between an open position, in which the flow passage defines a state in which fluid can flow through, and a closed position, in which the flow passage defines a state in which fluid is closed off. The clamping device includes a plunger element designed to be able to switch between the open position and the closed position by a translational movement. The clamping device only includes a single plunger element, which results in particularly large deformation and mechanical strain of the tubular valve member.

[0005] The above-mentioned pinch valve uses the method of introducing positive pressure into the valve cavity to push the flexible tubular valve member to expand outward, thereby opening the valve. In theory, this can reduce the wear caused by mechanical extrusion. However, this method has safety hazards in practical applications, especially under high pressure driving conditions. The continuous high internal pressure in the valve cavity significantly increases the circumferential stress of the tubular valve member, which can easily cause excessive material expansion, accelerated fatigue, and even sudden rupture. Once a pipe burst accident occurs, not only will it cause fluid leakage and equipment damage, but it may also cause personal injury. Therefore, there is currently a need for a negative pressure driven normally closed pinch valve that can achieve reliable sealing. SUMMARY

[0006] The rigid connecting sleeve and the flexible bellows sleeve are connected to each other, the rigid connecting sleeve and the tension piston are connected to each other, and the flexible bellows sleeve and the valve body are connected to each other, so that the gap between the tension piston and the valve body is eliminated, and the stability and reliability of the transmission sleeve operation are improved.

[0007] To solve the problems in the prior art, the present application provides a negative pressure driving type normally closed pipe clamping valve, which comprises a valve body, a valve cavity is arranged in the valve body, a tubular valve component and a plunger element cooperating with the tubular valve component to open and close the valve cavity are arranged in the valve cavity, a valve sleeve is arranged on the valve body, an annular air cavity is formed between the valve body and the valve sleeve, a transmission sleeve is arranged in the annular air cavity and slides on the valve body, a negative pressure port and a pressure relief port are arranged at two ends of the valve body and are communicated with the annular air cavity, a tension piston is threadedly connected to one end of the transmission sleeve facing the negative pressure port, a pushing part cooperating with the plunger element is arranged at one end of the transmission sleeve facing the pressure relief port, a step is arranged at the negative pressure side end of the valve body, a compression spring is arranged between the transmission sleeve and the step, a sealing connecting piece is arranged between the tension piston and the end face of the valve body, the sealing connecting piece comprises a rigid connecting sleeve and a flexible bellows sleeve, the rigid connecting sleeve is fixedly connected with the tension piston, and the two ends of the flexible bellows sleeve are fixedly connected with the end face of the valve body and the end face of the rigid connecting sleeve.

[0008] Preferably, a clamping structure for mutual connection is arranged between the rigid connecting sleeve and the flexible bellows sleeve, the clamping structure comprises a clamped part arranged at the end of the rigid connecting sleeve and a clamping part arranged at the end of the flexible bellows sleeve, the clamping part is an elastic hem, and the clamped part is provided with an annular groove matched with the elastic hem.

[0009] Preferably, the tension piston is coaxially arranged on the rigid connecting sleeve, the clamped part has a contact surface closely combined with the end face of the tension piston, and a first extrusion sleeve ring is threadedly connected to the rigid connecting sleeve and used to apply an axial pre-tightening force to the tension piston in the direction of the clamped part after being screwed.

[0010] Preferably, the first sealing glue is arranged at the connection between the outer circumferential surface of the tension piston and the end face of the transmission sleeve.

[0011] Preferably, the second sealing glue is arranged at the connection between the end face of the tension piston and the clamped part and the connection between the end face of the tension piston and the first extrusion sleeve ring, respectively.

[0012] Preferably, an insertion slot is arranged at the end face of the tension piston facing the first extrusion sleeve ring, a first gasket is arranged at the deep part of the insertion slot, and the first gasket is in a compressed and deformed state when the first extrusion sleeve ring is screwed, so that the first gasket abuts against the end face of the first extrusion sleeve ring.

[0013] Preferably, the relative sides of the clamped part and the clamping part are respectively provided with ring grooves, and a second gasket is arranged between the two ring grooves, so that when the clamped part and the clamping part are clamped, the second gasket is in a state of pressure deformation, and the two end faces of the second gasket abut against the clamped part and the clamping part respectively.

[0014] Preferably, a pressure maintaining sleeve capable of being threadedly connected with the clamped part is arranged on the clamping part, and the end of the pressure maintaining sleeve close to the clamping part is provided with an annular baffle extending inward, and the clamping part has a blocking surface capable of closely abutting against the annular baffle.

[0015] Preferably, a third gasket and a second extrusion sleeve ring threadedly connected with the valve body are arranged on the end of the flexible bellows sleeve close to the negative pressure side, so that when the second extrusion sleeve ring is tightened, the third gasket is in a state of pressure deformation, and the third gasket abuts against the end face of the second extrusion sleeve ring.

[0016] Preferably, lubricating oil is applied to the sliding interface between the rigid connecting sleeve and the valve body.

[0017] The beneficial effects of the present application compared with the prior art are:

[0018] 1. The clamped part at the end of the rigid connecting sleeve cooperates with the clamping part at the end of the flexible bellows sleeve, the elastic flange is embedded in the annular groove to form an interference fit, and the firm mechanical clamping of the two is realized. The radial and axial positioning between the elastic flange and the annular groove effectively prevents the flexible bellows sleeve from loosening or displacing due to stretching, vibration or pressure change during the operation of the transmission sleeve, and improves the stability and reliability of the connection.

[0019] At the same time, the closely fitted clamping interface forms a preliminary seal, which provides protection for the overall air tightness and ensures the long-term and effective dynamic sealing during driving.

[0020] 2. The present application coaxially arranges the tension piston on the rigid connecting sleeve, and uses the tightening of the first extrusion sleeve ring to apply axial pressure, so that the end face of the tension piston closely abuts against the contact surface of the clamped part, effectively eliminates the assembly gap, enhances the connection stiffness and prevents loosening during operation. The first gasket arranged in cooperation is elastically deformed under extrusion, further maintaining the pre-tightening force, absorbing vibration, and improving the connection stability and sealing performance.

[0021] At the same time, the interfaces of the tension piston and the transmission sleeve, the tension piston and the clamped part, and the tension piston and the first extrusion sleeve ring are coated with sealant, and after curing, airtight adhesive layer and continuous dense sealing layer are formed, effectively blocking the leakage path, enhancing the structural strength, inhibiting fretting wear, and ensuring the long-term sealing reliability and operation stability of the transmission sleeve under frequent operation and complex working conditions.

[0022] 3. The present application realizes reliable static sealing of the inside of the clamping structure by the second gasket between the ring groove of the clamped part and the clamping part, which is compressed to produce complex deformation after clamping, forming a continuous sealing pre-tightening force, effectively filling the micro gaps of the interface, and realizing reliable static sealing of the inside of the clamping structure. Further, by tightening the pressure retaining sleeve, the elastic flange is pressed between the clamped parts by the annular stopper, forming multiple compression seals, enhancing the mechanical strength and air tightness of the connection, and preventing loosening and leakage.

[0023] At the same time, the third gasket is compressed by the second extrusion sleeve ring, which establishes a stable sealing connection between the flexible bellows and the valve body, effectively blocking the leakage path of the end face. The multi-stage gasket and sleeve ring structure work together to greatly improve the sealing integrity, durability and overall operation reliability of the connection part. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a perspective structural schematic diagram of a negative pressure driven normally closed pinch valve of the present application.

[0025] Figure 2 is a plane cross-sectional view of a negative pressure driven normally closed pinch valve of the present application.

[0026] Figure 3 is a perspective structural cross-sectional view of a negative pressure driven normally closed pinch valve of the present application.

[0027] Figure 4 is an enlarged schematic view of A of the present application. Figure 2

[0028] Figure 5 is a partial plane cross-sectional view of a negative pressure driven normally closed pinch valve of the present application.

[0029] Figure 6 is a partial perspective structural cross-sectional view of a negative pressure driven normally closed pinch valve of the present application.

[0030] Figure 7 is an enlarged schematic view of B of the present application. Figure 5

[0031] Figure 8 is an enlarged schematic view of C of the present application. Figure 5

[0032] Figure 9 is an enlarged schematic view of D of the present application. Figure 5

[0033] Figure 10 is an enlarged schematic view of E of the present application. Figure 5

[0034] ​​​​​The figure marks: 1, valve body; 11, valve cavity; 12, annular air cavity; 121, negative pressure port; 122, pressure relief port; 13, step; 131, compression spring; 2, rubber tube; 3, gate plate; 4, valve sleeve; 5, transmission sleeve; 51, tension piston; 511, push part; 512, first sealing rubber; 513, second sealing rubber; 52, thrust piston; 521, sealing ring; 6, sealing connector; 61, rigid connecting sleeve; 611, clamped part; 612, first extrusion sleeve ring; 6121, first gasket; 62, flexible bellows sleeve; 621, clamped part; 6211, second gasket; 622, pressure maintaining sleeve; 6221, annular stopper; 623, second extrusion sleeve ring; 6231, third gasket. DETAILED DESCRIPTION

[0035] In order to further understand the features, technical means and specific purposes and functions of the present application, the present application will be described in detail below in combination with the drawings and specific embodiments.

[0036] Reference Figures 1-6 As shown in the figure, a negative pressure driven normally closed pinch valve, comprising a valve body 1, the valve body 1 is internally provided with a valve cavity 11, the valve cavity 11 is provided with a tubular valve member and a plunger element cooperating with the tubular valve member to open and close the valve cavity 11, further comprising a valve sleeve 4 sleeved on the valve body 1, an annular air cavity 12 is formed between the valve body 1 and the valve sleeve 4, a transmission sleeve 5 is slidably sleeved on the valve body 1 in the annular air cavity 12, the two ends of the valve body 1 are respectively provided with a negative pressure port 121 and a pressure relief port 122 which communicate with the annular air cavity 12, a tension piston 51 is threadedly connected to one end of the transmission sleeve 5 which faces the negative pressure port 121, a push part 511 which cooperates with the plunger element is arranged at the end of the transmission sleeve 5 which faces the pressure relief port 122, a step 13 is arranged at the negative pressure side end of the valve body 1, a compression spring 131 is arranged between the transmission sleeve 5 and the step 13, a sealing connector 6 is arranged between the tension piston 51 and the end face of the valve body 1, the sealing connector 6 comprises a rigid connecting sleeve 61 and a flexible bellows sleeve 62, the rigid connecting sleeve 61 is fixedly connected with the tension piston 51, the two ends of the flexible bellows sleeve 62 are fixedly connected with the end face of the valve body 1 and the end face of the rigid connecting sleeve 61 respectively, when the tension piston 51 is driven by the negative pressure to slide to the negative pressure side against the elastic force of the compression spring 131, the flexible bellows sleeve 62 is gradually compressed, so that the sliding interface between the tension piston 51 and the valve body 1 is kept sealed.

[0037] The transmission sleeve 5 and the valve sleeve 4 are gap fitted, a thrust piston 52 which abuts against the push part 511 is further arranged at the end of the transmission sleeve 5 which faces the pressure relief port 122, the thrust piston 52 is provided with a sealing ring 521 which tightly abuts against the valve body 1 and the valve sleeve 4.

[0038] The tubular valve member is specifically a rubber tube 2 fixedly connected with the valve body 1 at both ends, and the rubber tube 2 has elastic deformation characteristics.

[0039] The plunger element includes two symmetrical flappers 3 arranged on both sides of the rubber tube 2, and the valve body 1 is provided with flapper openings for the corresponding flappers 3 to move radially along the valve cavity 11.

[0040] When the negative pressure driving type normally closed pinch valve is in the initial closed state, the system does not apply negative pressure, the annular air cavity 12 is communicated with the atmosphere through the pressure relief port 122, and at this time the transmission sleeve 5 is kept in a stable position under the action of the compression spring 131. One end of the compression spring 131 abuts against the step 13 inside the valve body 1, and the other end acts on the transmission sleeve 5, so that the end of the transmission sleeve 5 towards the pressure relief port 122 is maintained at a set initial position. In this state, the pushing part 511 of the transmission sleeve 5 transmits force to the thrust piston 52 through the abutment with the thrust piston 52, and the thrust piston 52 is kept under continuous pressure of the plunger element under the pushing of the pushing part 511.

[0041] The elastic force of the compression spring 131 prompts the transmission sleeve 5 to transmit pressure to the two flappers 3, so that they are folded towards the center of the valve cavity 11, thereby externally extruding the tubular valve member, i.e. the rubber tube 2, in the valve cavity 11. Since the rubber tube 2 itself has good elastic deformation characteristics, its peripheral wall is significantly deformed under the clamping action of the two flappers 3, and the internal flow channel is completely closed, realizing the normally closed function of the valve and ensuring that the fluid is in a reliable cut-off state when there is no driving signal.

[0042] When it is necessary to open the valve, the external vacuum source sucks into the annular air cavity 12 through the negative pressure port 121 on the valve body 1, forming a negative pressure environment. The negative pressure acts on the annular air cavity 12, and is first transmitted to the driving end composed of the tension piston 51 and the rigid connection sleeve 61. With the establishment of negative pressure, the air pressure in the annular air cavity 12 is reduced, and the tension piston 51 generates an axial tension force towards the negative pressure port 121 under the pressure difference formed by the atmospheric pressure and the negative pressure. The tension force overcomes the elastic force of the compression spring 131, and drives the transmission sleeve 5 to slide along the valve body 1 towards the negative pressure side as a whole.

[0043] During the movement, the transmission sleeve 5 and the valve sleeve 4 are in clearance fit, which ensures the smoothness of sliding and avoids jamming or wear caused by too tight fit. With the movement of the transmission sleeve 5, the pushing part 511 at the end thereof towards the pressure relief port 122 retreats. The thrust piston 52 is simultaneously affected by the negative pressure effect and is converted into a thrust force acting on the transmission sleeve 5, which drives the transmission sleeve 5 to move towards the negative pressure side together with the tension piston 51.

[0044] With the retreat of the push part 511, the clamping force acting on the two gate plates 3 is released, and the elastic rubber tube 2 begins to recover under the joint action of its own material elasticity and internal fluid pressure. Its squeezed closed channel gradually opens, and the fluid can flow through the valve cavity 11, realizing the opening of the valve. At this time, the tension piston 51 is continuously driven by negative pressure to move to the negative pressure port 121 direction, driving the flexible bellows 62 to occur axial compression deformation. In the sliding process of the tension piston 51, the flexible bellows 62 is compressed, and the bellows structure is elastically deformed, always maintaining the dynamic seal between the tension piston 51 and the end face of the valve body 1, preventing external air from entering the gap between the rigid connecting sleeve 61 and the valve body 1, and ensuring the stability and response accuracy of the driving process.

[0045] When it is necessary to close the valve, stop the negative pressure supply, the compression spring 131 resets, and the pressure relief port 122 automatically releases pressure. At this time, the pressure difference acting on the tension piston 51 disappears, the drive sleeve 5 moves reversely, and resets to the initial position. The push part 511 advances forward, re-pushes the thrust piston 52, and makes the two gate plates 3 close again, squeezes the rubber tube 2, closes the flow passage, and the valve returns to the normally closed state. The whole driving process relies on negative pressure opening and compression spring 131 resetting to avoid high pressure risk, and through the dynamic seal of the flexible bellows 62 and the rigid connecting sleeve 61, the stability and sealing performance of long-term operation are ensured.

[0046] Referring to Figure 5 , Figure 6 and Figure 9 , a clamping structure for mutual connection is provided between the rigid connecting sleeve 61 and the flexible bellows 62, the clamping structure includes a clamped part 611 provided at the end of the rigid connecting sleeve 61 and a clamping part 621 provided at the end of the flexible bellows 62, the clamping part 621 is an elastic hem, and the clamped part 611 is provided with an annular groove matched with the elastic hem.

[0047] When assembling, first, the end of the flexible bellows 62 is pre-fabricated into an inwardly folded elastic hem as a clamping part 621, and a clamped part 611 with an annular groove is machined at the end of the rigid connecting sleeve 61. The geometric shape of the annular groove is matched with the elastic hem to ensure that the two can be tightly fitted.

[0048] During assembly, the elastic hem of the flexible bellows 62 is aligned with the clamped part 611 at the end of the rigid connecting sleeve 61, and an axial pressure is applied, so that the elastic hem gradually embeds into the annular groove under guidance. During embedding, the elastic hem is elastically deformed to fit the inner wall profile of the annular groove, and after being completely in place, it recovers part of the elasticity, so as to form an interference fit with the annular groove, realizing firm mechanical clamping.

[0049] And in the transmission sleeve 5 operation process, the clamping structure through the radial and axial limit between the elastic curling and the annular groove, effectively prevent the flexible bellows 62 from loosening or displacement due to stretching, vibration or pressure change in the use process, ensure the stability and reliability of the connection between the rigid connection sleeve 61 and the flexible bellows 62. At the same time, the close fit of the elastic curling and the annular groove also forms a preliminary sealing interface, which lays the foundation for the realization of the subsequent overall sealing performance.

[0050] Referring to Figure 5 、 Figure 6 and Figure 8 , the tension piston 51 is coaxially sleeved on the rigid connection sleeve 61, the clamped part 611 has a contact surface closely fitted with the end surface of the tension piston 51, and the rigid connection sleeve 61 is threadedly connected with a first extrusion sleeve ring 612 for applying axial pre-tightening force to the tension piston 51 in the direction of the clamped part 611 after being screwed.

[0051] In the assembly process, the tension piston 51 is first coaxially sleeved on the outer periphery of the rigid connection sleeve 61, with one end extending to the position of the clamped part 611 at the end of the rigid connection sleeve 61, and the end surface of the tension piston 51 is ensured to be in face-to-face contact with the contact surface provided on the clamped part 611, forming a stable axial force transmission interface.

[0052] Subsequently, the first extrusion sleeve ring 612 is screwed into the pre-set threaded section on the outer periphery of the rigid connection sleeve 61, and as the first extrusion sleeve ring 612 is gradually tightened, the inner end surface begins to contact the other end surface of the tension piston 51 and continuously applies axial pressure. The pressure pushes the tension piston 51 to move in the direction of the clamped part 611, so that the end surface of the tension piston 51 and the contact surface of the clamped part 611 remain closely fitted, eliminating assembly gaps and enhancing connection stiffness.

[0053] And in the transmission sleeve 5 operation process, the first extrusion sleeve ring 612 extrudes the tension piston 51 to ensure that it does not loosen axially due to vibration or dynamic load in subsequent operation, thereby ensuring the stability and reliability of the connection between the clamped part 611 and the tension piston 51. At the same time, the close fit of the tension piston 51 and the rigid connection sleeve 61 also forms a preliminary sealing interface, which lays the foundation for the realization of the subsequent overall sealing performance.

[0054] Referring to Figures 5-7 , the outer periphery of the tension piston 51 is provided with a first sealing rubber 512 at the connection with the end surface of the transmission sleeve 5.

[0055] The first sealant 512 fills the tiny gaps at the interface between the tension piston 51 and the transmission sleeve 5, and after curing, forms a strong and airtight adhesive sealing layer. The first sealant 512 not only effectively prevents the leakage of negative pressure or depressurized gas in the annular air chamber 12 through the connection between the tension piston 51 and the transmission sleeve 5, but also enhances the structural connection strength between the two, suppressing loosening or fretting wear caused by vibration or frequent axial movement.

[0056] The first sealant 512 is preferably an anaerobic adhesive or epoxy resin adhesive with excellent adhesion and environmental stability, which can adapt to temperature changes and mechanical stress during the operation of the pinch valve, ensuring long-term reliable sealing and further improving the response accuracy and service life of the pinch valve.

[0057] See Figure 5 , Figure 6 , Figure 8 and Figure 9 As shown, a second sealant 513 is provided at the end face connection between the tension piston 51 and the locked part 611, and at the end face connection between the tension piston 51 and the first compression collar 612.

[0058] The second sealant 513 fills the micro gaps at each contact interface and, after curing, forms a continuous and dense sealing layer, effectively blocking potential gas leakage paths.

[0059] By applying a second sealant 513 to the contact surface between the tension piston 51 and the locked part 611, airtightness defects caused by minor unevenness between the metal contact surfaces can be eliminated.

[0060] Meanwhile, the second sealant 513 applied at the connection between the end face of the first compression collar 612 and the tension piston 51 can prevent leakage caused by uneven distribution of thread preload or expansion of interface gap due to dynamic load.

[0061] The second sealant 513 used is preferably an anaerobic adhesive or epoxy resin adhesive with excellent adhesion and environmental stability. It can adapt to temperature changes and mechanical stress during the operation of the pinch valve, ensuring long-term reliable sealing and further improving the response accuracy and service life of the pinch valve.

[0062] See Figure 5 , Figure 6 and Figure 8 As shown, the tension piston 51 has a slot for insertion on the end face of the first compression ring 612. A first washer 6121 is provided deep in the slot. When the first compression ring 612 is tightened, the first washer 6121 is in a state of compression deformation, so that the first washer 6121 abuts against the end face of the first compression ring 612.

[0063] In the assembly process, when the first compression collar 612 starts to screw into the threaded section of the rigid connecting sleeve 61 and gradually tightens, its inner end face enters the insertion slot and contacts the first gasket 6121. As the tightening process continues, the first compression collar 612 continuously exerts axial pressure on the first gasket 6121, causing it to compress and elastically deform, tightly fitting the bottom of the insertion slot and maintaining sufficient abutment with the end face of the first compression collar 612.

[0064] During the operation of the transmission sleeve 5, the first gasket 6121 ensures a stable pre-tightening connection between the first compression collar 612 and the tension piston 51, effectively absorbing vibrations and preventing connection failure due to looseness, while enhancing the sealing between the insertion slot and the first compression collar 612.

[0065] Referring to Figure 5 , Figure 6 and Figure 9 , the opposite sides of the clamped part 611 and the clamped part 621 are respectively provided with ring grooves, and a second gasket 6211 is arranged between the two ring grooves. When the clamped part 611 and the clamped part 621 are clamped, the second gasket 6211 is in a compressed deformed state, so that the two end faces of the second gasket 6211 abut against the clamped part 611 and the clamped part 621 respectively.

[0066] In the assembly process, the elastic flange of the clamped part 621 is embedded in the annular groove of the clamped part 611 to complete clamping, and the second gasket 6211 is located in the ring groove region between the clamped part 611 and the clamped part 621. As the clamping action is completed, the clamped part 611 and the clamped part 621 are pressed tightly in the axial direction, causing the second gasket 6211 to be squeezed and undergo combined radial and axial deformation.

[0067] During the operation of the transmission sleeve 5, the two end faces of the second gasket 6211 in the compressed state tightly abut against the ring groove end faces of the clamped part 611 and the clamped part 621, generating a continuous sealing pre-tightening force, effectively filling the microscopic gaps between them, thereby forming a reliable static seal inside the clamping structure, preventing gas or liquid from leaking along the connection interface between the clamped part 611 and the clamped part 621, and improving the sealing integrity and durability of the connection part.

[0068] Referring to Figure 5 , Figure 6 and Figure 9 , a pressure maintaining sleeve 622 capable of being threadedly connected with the clamped part 611 is arranged on the clamped part 621. The pressure maintaining sleeve 622 has an annular retaining piece 6221 extending inwardly at one end close to the clamped part 621, and the clamped part 621 has a blocking surface capable of tightly abutting against the annular retaining piece 6221.

[0069] When the pressure retaining sleeve 622 is screwed into the clamped portion 611 and gradually tightened, the annular blocking piece 6221 synchronously presses the blocking surface of the clamped portion 621, tightly clamps the elastic crimping of the flexible bellows 62 between the annular blocking piece 6221 and the clamped portion 611, and forms a multiple compression sealing structure. Not only the mechanical strength of the clamped connection is enhanced to prevent loosening under negative pressure suction or vibration working conditions, but also the air tightness of the connection interface is improved to effectively block the leakage path along the root of the flexible bellows 62.

[0070] At the same time, the introduction of the pressure retaining sleeve 622 further improves the structural compactness and reliability of the entire tension piston 51, ensures the sealing stability and safe operation of the transmission sleeve 5 under long-term frequent operation and complex environment.

[0071] Referring to Figure 5 , Figure 6 and Figure 10 , the end of the flexible bellows 62 towards the negative pressure side is sleeved with a third gasket 6231 and a second extrusion sleeve ring 623 which is threadedly connected with the valve body 1. When the second extrusion sleeve ring 623 is tightened, the third gasket 6231 is in a compressed deformed state, so that the third gasket 6231 abuts against the end face of the second extrusion sleeve ring 623.

[0072] During assembly, the second extrusion sleeve ring 623 is screwed into the corresponding threaded section of the valve body 1. As the second extrusion sleeve ring 623 is tightened, its inner end face gradually approaches and contacts the third gasket 6231. Continue to apply torque, the second extrusion sleeve ring 623 exerts axial pressure on the third gasket 6231, causing it to elastically compress and deform, and be in a compressed state.

[0073] During the operation of the transmission sleeve 5, the end face of the third gasket 6231 abuts against the inner end face of the second extrusion sleeve ring 623, and the other end face abuts against the end face of the valve body 1, thereby forming a reliable sealing connection between the flexible bellows 62, the valve body 1 and the second extrusion sleeve ring 623, preventing gas from leaking through the connection interface, and ensuring the integrity and stability of the sealing structure.

[0074] Referring to Figure 5 , Figure 6 , Figure 8 and Figure 9 , lubricating oil is applied to the sliding interface between the rigid connecting sleeve 61 and the valve body 1.

[0075] Lubricating oil is applied to the sliding interface between the rigid connecting sleeve 61 and the valve body 1 to reduce the frictional resistance when the tension piston 51 drives the transmission sleeve 5 to move axially, ensure smooth movement and sensitive response of the tension piston 51 under negative pressure, reduce wear and tear, and prolong the service life of the rigid connecting sleeve 61 and the valve.

[0076] The applied lubricating oil has good adhesion and chemical stability, can adapt to the valve operating environment, and avoids rapid loss or deterioration due to high temperature or long-term use, thereby continuously ensuring the lubrication and sealing performance of the sliding interface.

[0077] The present application sets the clamped part 611 at the end of the rigid connecting sleeve 61, and forms an interference fit with the elastic crimped clamped part 621 of the flexible bellows sleeve 62, uses radial and axial limiting to prevent loosening, and improves the connection stability. The first extrusion collar 612 applies axial pressure to the tension piston 51, and in combination with the elastic pre-tightening of the first gasket 6121, effectively eliminates the gap, absorbs vibration, and enhances the structural rigidity.

[0078] The first sealant 512 and the second sealant 513 are coated at multiple interfaces to form an airtight adhesive layer, inhibit leakage and wear. At the same time, the second gasket 6211 is arranged in the ring groove between the clamped part 611 and the clamped part 621 and is deformed under pressure, to realize internal static sealing, and through the compression of the pressure retaining sleeve 622, multiple compression seals are formed, further improving the mechanical strength and air tightness. The flexible bellows sleeve 62 at the end is compressed by the third gasket 6231 through the second extrusion collar 623, to establish reliable sealing between the flexible bellows sleeve 62 and the valve body 1. The sealing integrity, durability and long-term operation reliability between the transmission sleeve 5 and the tension piston 51, and between the tension piston 51 and the valve body 1 are improved as a whole.

[0079] The above embodiments only express one or several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the protection scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A negative pressure driven normally closed pinch valve, comprising a valve body, a valve cavity inside the valve body, a tubular valve component and a plunger element that cooperates with the valve cavity to open and close the valve cavity; Its features are, It also includes a valve sleeve fitted on the valve body, forming an annular air cavity between the valve body and the valve sleeve, and a transmission sleeve that is slidably fitted on the valve body is provided in the annular air cavity. The valve body has a negative pressure port and a pressure relief port at both ends, which are connected to the annular air chamber. The transmission sleeve is threaded to a tension piston at the end facing the negative pressure port, and a push part that cooperates with the plunger element is provided at the end facing the pressure relief port. The valve body has a step at the negative pressure side end, and a compression spring is provided between the transmission sleeve and the step; A sealing connector is provided between the tension piston and the valve body end face. The sealing connector includes a rigid connecting sleeve and a flexible corrugated sleeve sleeved on the valve body. The rigid connecting sleeve is fixedly connected to the tension piston, and the two ends of the flexible corrugated sleeve are fixedly connected to the valve body end face and the rigid connecting sleeve end face, respectively. When the tension piston slides towards the negative pressure side against the spring force of the compression spring under negative pressure, the flexible bellows is gradually compressed, so that the sliding interface between the tension piston and the valve body remains sealed. The tubular valve component is specifically a rubber tube that is fixedly connected to the valve body at both ends, and the rubber tube has elastic deformation characteristics. The plunger element includes two gates symmetrically arranged on both sides of the hose, and the valve body is provided with a gate for the corresponding gate to move radially along the valve cavity; When the negative pressure driven normally closed pinch valve is in the initial closed state, the elastic force of the compression spring causes the transmission sleeve to transmit pressure to the two gates, causing them to close towards the center of the valve cavity; Under the clamping action of the two gates, the periphery of the hose undergoes significant deformation, and the internal flow channel is completely closed, thus realizing the normally closed function of the valve. When the valve needs to be opened, an external vacuum source draws air into the annular chamber through the negative pressure port on the valve body to create a negative pressure environment. As the pushing part retracts, the clamping force acting on the two gates is released. Under the combined action of its own material elasticity and internal fluid pressure, the elastic hose begins to return to its original shape, and its squeezed and closed channel gradually opens, allowing fluid to flow through the valve cavity and realize the opening of the valve.

2. The negative pressure driven normally closed pinch valve according to claim 1, characterized in that, A snap-fit ​​structure for mutual connection is provided between the rigid connecting sleeve and the flexible corrugated sleeve. The snap-fit ​​structure includes a snap-fit ​​part provided at the end of the rigid connecting sleeve and a snap-fit ​​part provided at the end of the flexible corrugated sleeve. The snap-fit ​​part is an elastic rolled edge, and the snap-fit ​​part is provided with an annular groove adapted to the elastic rolled edge.

3. The negative pressure driven normally closed pinch valve according to claim 2, characterized in that, The tension piston is coaxially sleeved on the rigid connecting sleeve. The clamped part has a contact surface that fits tightly with the end face of the tension piston. The rigid connecting sleeve is threaded with a first compression collar for applying an axial preload to the tension piston in the direction of the clamped part after tightening.

4. A negative pressure driven normally closed pinch valve according to claim 3, characterized in that, A first sealant is provided at the connection between the outer circumferential surface of the tension piston and the end face of the transmission sleeve.

5. A negative pressure driven normally closed pinch valve according to claim 3, characterized in that, A second sealant is provided at the connection between the tension piston and the clamped part, and at the end face connection between the tension piston and the first compression collar.

6. A negative pressure driven normally closed pinch valve according to claim 5, characterized in that, The end face of the tension piston facing the first compression ring has a slot for it to be inserted. A first washer is provided deep in the slot. When the first compression ring is tightened, the first washer is in a state of compression deformation, so that the first washer abuts against the end face of the first compression ring.

7. A negative pressure driven normally closed pinch valve according to claim 2, characterized in that, The locking part and the locking part are respectively provided with annular grooves on opposite sides, and a second washer is provided between the two annular grooves. When the locking part and the locking part are locked together, the second washer is in a state of compression deformation, so that the two end faces of the second washer abut against the locking part and the locking part respectively.

8. A negative pressure driven normally closed pinch valve according to claim 7, characterized in that, A pressure-holding sleeve that can be threadedly connected to the snapped part is fitted on the snapping part. An inwardly extending annular baffle is provided at one end of the pressure-holding sleeve near the snapping part. The snapping part has a blocking surface that can fit tightly with the annular baffle.

9. A negative pressure driven normally closed pinch valve according to claim 2, characterized in that, A third washer and a second compression ring threaded to the valve body are fitted on one end of the flexible corrugated sleeve facing the negative pressure side. When the second compression ring is tightened, the third washer is in a state of compression deformation, so that the third washer abuts against the end face of the second compression ring.

10. A negative pressure driven normally closed pinch valve according to claim 1, characterized in that, Lubricating oil is applied to the sliding interface between the rigid connecting sleeve and the valve body.

Images