Two-stage opening and closing axial flow type check valve

Abstract

The utility model discloses a two-stage opening and closing axial flow type check valve, and belongs to the field of check valves. According to the check valve, the first elastic element and the second elastic element are arranged at the rear end of the valve shaft, the first elastic element and the second elastic element form a tandem relay type double-elastic-force pushing structure, and specifically, in the valve opening process, the first elastic element controls the valve clack to slowly open the stroke of the first sliding distance; the second elastic element controls the valve clack to slowly open the stroke of the second sliding distance, so that the valve clack is stably attached to the contact surface of the flow guide body; in the valve closing process, the second elastic element controls the valve clack to rapidly close the stroke of the second sliding distance, the first elastic element controls the valve clack to slowly close the stroke of the first sliding distance, and especially in the final stage of valve closing, zero-flow-velocity valve closing is achieved. And finally, the zero flow velocity of a water column is automatically tracked through segmented relay type spring strain to achieve second-stage servo type valve closing, the valve closing water hammer of the check valve is eliminated or greatly reduced, and the structural design is simple and reliable.

Description

Technical Field

[0001] The utility model relates to the technical field of check valves, and more specifically to a two-stage opening and closing axial flow check valve. Background Art

[0002] A check valve is an automatic valve that controls the one-way flow of a medium. In industrial pipelines, in order to prevent the medium from flowing back and causing damage to the power pump, a check valve is often designed and installed after the pump. As a check valve after the pump, it prevents the medium from flowing back after the pump is stopped, so that the medium can only flow in one direction and cut off the pressure wave in time. Check valves are divided into axial flow type, swing type, butterfly type, double flap type, etc.

[0003] The existing axial flow check valve is only provided with a single spring, or multiple parallel springs are provided for multiple valve discs, and the valve disc performs opening and closing movements under the action of a single spring and a medium. For example, Chinese patent CN109826983A discloses a cold axial flow check valve, in which a spring for resetting the valve disc and acting as a buffer is provided between the valve disc and the bushing, and the spring is sleeved on the valve shaft. In this scheme, the opening and closing of the valve disc is controlled by a spring, but a single spring can only produce one valve closing speed, making it difficult to achieve a servo-type zero-flow rate valve closing at the last moment, and this type of axial flow check valve is also prone to causing large water loss, valve disc vibration, and valve closing water hammer. Utility Model Content

[0004] The utility model provides a two-stage opening and closing axial flow check valve to solve the problem in the prior art that during the closing or opening process of the check valve, the closing or opening speed is single and cannot be adjusted, which easily causes large water loss, valve disc vibration, and valve closing water hammer.

[0005] In order to achieve the above-mentioned purpose, the technical solution provided by the utility model is:

[0006] A two-stage opening and closing axial flow check valve, comprising:

[0007] A valve body, in which a valve cavity is formed, and two sides of the valve body are respectively provided with a liquid inlet and a liquid outlet connected to the valve cavity;

[0008] A guide body, located in the valve cavity and connected to the valve body, wherein a contact surface is provided at one end of the guide body close to the liquid inlet;

[0009] A valve flap, located in the valve cavity and disposed close to the contact surface of the guide body, capable of reciprocating along the axial center line of the guide body, and used for opening and closing the check valve;

[0010] Also includes,

[0011] A valve shaft, one end of which is sleeved in a guide shaft fixed relatively to the guide body and can slide in the guide shaft, and the other end of which is connected to the valve flap and drives the valve flap to move;

[0012] A first elastic element, one end of which is connected to one end of the valve shaft located in the guide shaft and provides a first elastic force and a first sliding distance for the valve shaft;

[0013] A seat body is located in the guide shaft and can slide in the guide shaft; and one end of the valve shaft located in the guide shaft can abut against one side of the seat body, and the other end of the first elastic element also abuts against the side of the seat body;

[0014] A second elastic element, one end of which abuts against the other side of the seat body, and the other end of which abuts against a gland fixed relatively to the guide body; a gland through hole is provided on the gland; the second elastic element provides a second elastic force and a second sliding distance for the valve shaft;

[0015] The first elastic element and the second elastic element have different elastic coefficients, and the sum of the first sliding distance and the second sliding distance is the movement stroke of the valve flap when opening or closing the valve body.

[0016] The utility model arranges a first elastic element and a second elastic element at the rear end of the valve shaft. The first elastic element and the second elastic element form a series relay-type double elastic force pushing structure. Two different and changing elastic elements are used to servo-type to cope with the change of the fluid thrust in the valve body flow channel, so as to realize the two-stage opening and closing of the check valve. The segmented relay-type spring strain is used to automatically track the zero flow rate of the water column to realize the second-stage servo-type valve closing, thereby eliminating or greatly reducing the valve closing water hammer of the check valve itself, and the structural design is simple and reliable.

[0017] As a further improvement of the two-stage opening and closing axial flow check valve, the elastic coefficient of the first elastic element is smaller than the elastic coefficient of the second elastic element, and the first sliding distance is larger than the second sliding distance. During the valve opening process, the first elastic element controls the valve flap to slowly open the first sliding distance, and the second elastic element controls the valve flap to slowly open the second sliding distance, so that the valve flap is stably in contact with the contact surface of the guide body; during the valve closing process, the second elastic element controls the valve flap to quickly close the second sliding distance, and the first elastic element controls the valve flap to slowly close the first sliding distance, especially in the final stage of valve closing, to achieve zero flow rate valve closing.

[0018] As a further improvement of the two-stage opening and closing axial flow check valve, a seat body through hole is also provided on the seat body. The seat body includes a seat body connecting section and a seat body supporting section located at one end of the seat body connecting section, and one end of the first elastic element connected to the seat body is sleeved on the seat body connecting section, and the end abuts against the seat body supporting section. One end of the first elastic element and one end of the valve shaft both abut against the seat body supporting section, and the first elastic element and the second elastic element are relayed through the seat body to control the sliding of the valve shaft.

[0019] As an implementation mode of the two-stage opening and closing axial flow check valve, one end of the valve shaft sleeved in the guide shaft is the rear end of the valve shaft, and a valve shaft accommodating hole is opened inside the rear end of the valve shaft of the valve shaft, the first elastic element is located in the valve shaft accommodating hole, and one end of the first elastic element abuts against the bottom of the valve shaft accommodating hole, and the valve shaft accommodating hole is connected to the pressure cover through hole.

[0020] As a further improvement of the two-stage opening and closing axial flow check valve, the valve shaft is threadedly connected to the valve disc, one end of the valve shaft connected to the valve disc is also connected to a locking piece, and a sealing piece is also provided on the valve disc.

[0021] Preferably, a through hole is provided at the center of the guide body, the guide shaft is fixed in the through hole, and the pressure cover is fixedly connected to the guide shaft.

[0022] As a further improvement of the two-stage opening and closing axial flow check valve, the rear end of the flow guide body is integrally connected to a cantilever, and the other end of the cantilever is connected to an annular flow guide body connecting portion, and the flow guide body connecting portion is detachably connected to the valve body.

[0023] As another implementation of the two-stage opening and closing axial flow check valve, the middle portion of the body guide is integrally connected to a cantilever, and the other end of the cantilever is integrally connected to the valve body.

[0024] As a further improvement of the two-stage opening and closing axial flow check valve, the valve body includes a valve body front section arranged close to the liquid inlet and a valve body middle section connected to the valve body front section; the inner diameter of the valve body front section gradually decreases from front to back.

[0025] As a further improvement of the two-stage opening and closing axial flow check valve, the valve body comprises a valve body front section arranged near the liquid inlet and a valve body middle section connected to the valve body front section;

[0026] A detachable valve seat is connected to the front section of the valve body, and the valve seat includes a front section of the valve seat arranged near the valve seat inlet and a rear end of the valve seat arranged near the valve seat outlet. The inner diameter of the front section of the valve seat gradually decreases from front to back, and the inner diameter of the rear end of the valve seat gradually increases from front to back.

[0027] Other technical problems that can be solved by the two-stage opening and closing axial flow check valve of the utility model, other technical features included in the technical solution and the advantages brought by these technical features will be further described in detail in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the check valve structure of Example 1;

[0029] Figure 2 for Figure 1 A schematic diagram of the structure of the check valve at position A;

[0030] Figure 3 This is a schematic diagram of the check valve structure of Example 2;

[0031] Figure 4 This is a schematic diagram of the check valve structure in another case in Example 2;

[0032] Figure 5 This is a schematic diagram of the closed state of the check valve in Example 1;

[0033] Figure 6 This is a schematic diagram of the first stage opening state of the check valve in Example 1;

[0034] Figure 7 This is a schematic diagram of the fully open state of the check valve in Example 1;

[0035] Figure 8 This is a schematic diagram of the first stage closing state of the check valve in Example 1.

[0036] Description of labels:

[0037] 100, valve body; 101, liquid inlet; 102, liquid outlet; 103, front section of valve body; 104, middle section of valve body;

[0038] 200, valve disc; 201, elastic sealing ring; 202, valve disc slot; 203, first rigid sealing ring;

[0039] 300, valve shaft; 301, valve shaft front end; 302, valve shaft rear end; 303, valve shaft accommodating hole; 304, first elastic element; 305, seat body; 3051, seat body through hole; 3052, seat body connecting section; 3053, seat body supporting section; 306, second elastic element; 307, gland; 3071, gland through hole; 308, locking member; 309, guide member;

[0040] 400, flow guide body; 401, cantilever; 402, flow guide body connection part;

[0041] 500, guide shaft;

[0042] 600, valve seat; 601, front section of valve seat; 602, rear end of valve seat; 603, valve seat groove; 604, second rigid sealing ring. DETAILED DESCRIPTION

[0043] The present invention will be described in detail with reference to the accompanying drawings. What is described here is only a preferred embodiment of the present invention, and those skilled in the art can think of other ways to implement the present invention based on the preferred embodiment, and other ways also fall within the scope of the present invention.

[0044] In the water pump pressurized pipeline system, water hammer backflow is easy to impact the water pump after the pump is stopped. In order to avoid this phenomenon, a check valve is often set after the pump to prevent the liquid medium from flowing back after the pump is stopped and to cut off the pressure wave in time. This embodiment provides a two-stage opening and closing axial flow check valve. In the process of closing the check valve, the valve disc can achieve slow closing in the final valve closing stage, and can close the valve when the water column has zero flow rate or close to zero flow rate, so that the check valve does not generate its own valve closing water hammer or only generates a small valve closing water hammer, reducing the generation of valve closing water hammer.

[0045] Example 1

[0046] Combination Figure 1 and Figure 2 As shown, the check valve in this embodiment includes a valve body 100 , a guide body 400 and a valve flap 200 .

[0047] A valve cavity is formed in the valve body 100, and a liquid inlet 101 and a liquid outlet 102 communicating with the valve cavity are formed on both sides of the valve body 100. Figure 1 The liquid medium enters from the liquid inlet 101 and flows out from the liquid outlet 102. The side of the liquid inlet 101 where the liquid medium enters is the front side of the check valve, and the side of the liquid outlet 102 where the liquid medium flows out is the rear side of the check valve.

[0048] More specifically, the valve body 100 in this embodiment includes a valve body front section 103 disposed near the liquid inlet 101 and a valve body middle section 104 connected to the valve body front section 103. The inner diameter of the valve body front section 103 gradually decreases from front to back, and the inner diameter of the valve body middle section 104 gradually increases and then gradually decreases from front to back until it is connected to the liquid outlet 102. A Venturi effect is formed in the valve body 100 at the location where the inner diameter is the smallest, and a nozzle is formed at this location.

[0049] The flow guide 400 is located in the valve cavity and connected to the valve body 100, and a contact surface is provided at one end of the flow guide 400 close to the liquid inlet 101. The rear end of the flow guide 400 is integrally connected to a plurality of cantilevers 401, and the other ends of the plurality of cantilevers 401 are connected to an annular flow guide connection part 402, and the flow guide connection part 402 is detachably connected to the valve body 100. Specifically, an external thread is provided on the outer side of the flow guide connection part 402, and an internal thread is provided at a portion of the valve body 100 that cooperates with the flow guide connection part 402, so that the flow guide connection part 402 and the valve body 100 are connected together by threads, which facilitates the disassembly and installation of the flow guide 400.

[0050] The valve flap 200 is located in the valve cavity and is arranged close to the contact surface of the flow guide 400. It can move back and forth along the axial center line of the flow guide 400 to open and close the check valve.

[0051] The check valve in this embodiment further includes a valve shaft 300 , a seat body 305 , a first elastic element 304 and a second elastic element 306 .

[0052] One end of the valve shaft 300 is sleeved in the guide shaft 500 fixed relatively to the guide body 400 and can slide in the guide shaft 500, and the other end is connected to the valve flap 200 and drives the valve flap 200 to move back and forth. Specifically, one end of the valve shaft 300 is sleeved in the guide shaft 500, and the other end extends from the guide shaft 500 to connect with the valve flap 200. When the valve shaft 300 slides back and forth in the guide shaft 500, it drives the valve flap 200 to move back and forth synchronously, thereby correspondingly opening and closing the check valve. The end of the valve shaft 300 extending from the guide shaft 500 is the valve shaft front end 301, and the valve flap slot 202 is set at the center of one side of the valve flap 200 close to the contact surface of the guide body 400, and the valve shaft front end 301 is connected to the valve flap slot 202. Furthermore, the inner wall of the valve flap slot 202 is provided with an internal thread, the front end 301 of the valve shaft is provided with an external thread, and the valve shaft 300 is connected to the valve flap slot 202 through the thread, so that the valve flap 200 is easy to disassemble and install. The end of the valve shaft 300 connected to the valve flap 200 is also connected to a locking member 308, which can be a locking nut or other locking components, and is used to lock the connection between the valve shaft 300 and the valve flap 200 to prevent the valve flap 200 from loosening from the valve shaft 300.

[0053] A sealing ring is also provided on the valve flap 200. When the valve flap 200 moves toward the direction close to the liquid inlet 101 until the edges of the valve flap 200 abut against the valve body 100, the sealing ring and the valve body 100 are in close contact to form a seal, thereby closing the check valve. In this embodiment, the sealing ring is an elastic sealing ring 201, which forms a soft seal with the valve body 100, so that the sealing effect is better when the check valve is closed.

[0054] Regarding the setting of the guide shaft 500, a preferred way in this embodiment is that a through hole is set in the center of the guide body 400 and along the axial center line direction of the guide body 400, and the guide shaft 500 is fixed in the through hole. The cross section of the guide shaft 500 is annular, and there is a space for the valve shaft 300 to slide back and forth. However, in other cases, the guide shaft 500 can also be set as a part of the guide body 400 and is set together with the guide body 400.

[0055] One end of the first elastic element 304 is connected to one end of the valve shaft 300 located in the guide shaft 500 and provides a first elastic force and a first sliding distance when the valve shaft 300 slides. The other end of the first elastic element 304 is connected to the seat body 305 .

[0056] The seat body 305 is located in the guide shaft 500 and can slide in the guide shaft 500, and one end of the valve shaft 300 located in the guide shaft 500 can abut against one side of the seat body 305, the valve shaft 300 and the first elastic element 304 are located on the same side of the seat body 305, and the second elastic element 306 is located on the other side of the seat body 305.

[0057] One end of the second elastic element 306 is connected to the seat body 305, and the other end is against the gland 307 fixedly arranged relative to the guide body 400. The gland through hole 3071 is provided on the gland 307, and the gland through hole 3071 is connected to the space inside the guide shaft 500 and the valve cavity. The second elastic element 306 provides a second elastic force and a second sliding distance for the valve shaft 300 to slide.

[0058] Regarding the setting of the gland 307, a preferred method in this embodiment is that the gland 307 is fixedly connected to the guide shaft 500. Specifically, a connection hole is provided near the edge of the gland 307, and a bolt passes through the connection hole to fix the gland 307 to one end of the guide shaft 500. However, in other cases, the gland 307 can also be fixedly connected to the guide body 400. In another case, the gland 307 can also be integrally arranged with the guide body 400, and the gland 307 serves as a part of the guide body 400; or the gland 307 can also be integrally arranged with the guide shaft 500, and the gland 307 serves as a part of the guide shaft 500.

[0059] The first elastic element 304 and the second elastic element 306 are respectively connected to the two sides of the seat body 305, and the seat body through hole 3051 is also provided on the seat body 305, and the seat body through hole 3051 is connected to the space in the guide shaft 500. In this embodiment, the first elastic element 304 and the second elastic element 306 are both springs, but other elastic elements are not excluded in other cases.

[0060] More specifically, the seat body 305 in this embodiment includes a seat body connecting section 3052 and a seat body supporting section 3053 located at one end of the seat body connecting section 3052, and the outer side of the seat body supporting section 3053 is slidably connected to the inner side of the guide shaft 500. One end of the first elastic element 304 connected to the seat body 305 is sleeved on the seat body connecting section 3052, and the end abuts against the seat body supporting section 3053, and the first elastic element 304 and the second elastic element 306 are respectively located on both sides of the seat body supporting section 3053.

[0061] Regarding the setting position of the first elastic element 304, as a preferred mode, in this embodiment, the first elastic element 304 is set in the valve shaft 300. Specifically, the end of the valve shaft 300 sleeved in the guide shaft 500 is the valve shaft rear end 302, and the valve shaft receiving hole 303 is provided inside the valve shaft rear end 302 of the valve shaft 300. The first elastic element 304 is located in the valve shaft receiving hole 303, and one end of the first elastic element 304 abuts against the bottom of the valve shaft receiving hole 303, and the other end of the first elastic element 304 abuts against the seat body support section 3053, and at the same time, the end of the valve shaft receiving hole 303 close to the seat body 305 also abuts against the seat body support section 3053. In addition, the valve shaft receiving hole 303 is connected with the gland through hole 3071.

[0062] In another case, the diameter of the valve shaft rear end 302 is smaller than the diameter of other positions of the valve shaft 300, so that a connecting step is formed between the valve shaft rear end 302 and other positions of the valve shaft 300, and the first elastic element 304 is sleeved on the outer side of the valve shaft rear end 302, with one end of the first elastic element 304 abutting on the connecting step and the other end abutting on the seat body support section 3053. The valve shaft rear end 302 and one end of the first elastic element 304 close to the seat body 305 both abut on the seat body support section 3053.

[0063] In this embodiment, the elastic coefficients of the first elastic element 304 and the second elastic element 306 are different, and the sum of the first sliding distance and the second sliding distance is the total movement stroke of the valve flap 200 when opening or closing the valve body 100. Moreover, the elastic coefficient of the first elastic element 304 is smaller than the elastic coefficient of the second elastic element 306, and the first sliding distance is greater than the second sliding distance.

[0064] In order to further understand the structure of the check valve of this embodiment, the relationship and function between the various components, and the way in which the check valve can achieve two-stage opening and closing, the operation process of the check valve of this embodiment will be further explained.

[0065] like Figure 5As shown, when the check valve is in the closed state, the valve shaft 300 extends to the maximum stroke, driving the elastic sealing ring 201 on the valve flap 200 to closely contact the valve body 100 to form a seal, so that the valve is closed and no medium flows in the valve body. At this time, the first elastic element 304 is in the initial compression state, the second elastic element 306 is in the free state, and the elastic force on the valve shaft 300 is at the minimum value.

[0066] like Figure 6 As shown, this is the state of the check valve after the first stage of opening. After the water pump is turned on, the front side of the valve flap 200 is pushed by the fluid, overcoming the first elastic force of the first elastic element 304, until the first elastic element 304 is compressed to make the valve shaft 300 slide a first sliding distance. At this time, the valve flap 200 is gradually opened to about 80% of the total stroke, the rear end 302 of the valve shaft abuts against the seat support section 3053, and the second elastic element 306 is still in a free state.

[0067] like Figure 7 As shown in the figure, the valve is fully open after the second stage of the check valve is opened. Figure 6 After the check valve is opened in the first stage, the elastic coefficient of the second elastic element 306 is greater than the elastic coefficient of the first elastic element 304. In the subsequent opening stroke of the valve flap 200 of about 20%, the front side of the valve flap 200 needs to be subjected to a greater thrust to overcome the second elastic force of the second elastic element 306. The valve body 100 in this embodiment forms a Venturi nozzle effect at the smallest diameter. At the nozzle, the flow channel cross-sectional area is the smallest, the flow velocity is the largest, and the pressure is the lowest. During the flow process, the fluid can be sucked out of the fluid inside the guide body 400 from the gap between the contact surface of the valve flap 200 and the guide body 400, further reducing the pressure on the rear side of the valve flap 200, thereby relatively increasing the valve opening force of the valve flap 200. The valve flap 200 thus completes the subsequent opening stroke of about 20%, so that the contact surface of the valve flap 200 and the guide body 400 are completely fitted, and the check valve completes the valve full opening process after the second stage. In addition, after the check valve is opened in the first stage, the rear end 302 of the valve shaft abuts against the seat support section 3053. After the thrust on the valve flap 200 overcomes the second elastic force of the second elastic element 306, the valve shaft 300 slides the second sliding distance and pushes the seat 305. The seat 305 pushes the second elastic element 306, so that the second elastic element 306 is compressed in turn, so that the check valve completes the second stage opening process. On the other hand, the elastic coefficient of the second elastic element 306 is relatively large, and the second stage opening process of the check valve is slow. The valve flap 200 can slowly fit the contact surface of the guide body 400, thereby reducing the vibration of the valve flap 200 and reducing noise.

[0068] It should be noted that a connecting guide 309 is also sleeved on the valve shaft 300, which is used to guide the valve shaft 300 during the sliding process in the guide shaft 500. The guide 309 is made of a material with low friction and wear resistance. The valve shaft 300 contacts the guide 309 and slides under the guidance of the guide 309. Compared with the contact between the valve shaft 300 and the guide shaft 500, the sliding contact area of ​​the valve shaft 300 can be reduced, the friction is reduced, and the sliding process of the valve shaft 300 is smoother. During the first and second stage opening processes, when the valve shaft 300 slides from front to back, the fluid medium in the valve shaft accommodating hole 303 and the guide shaft 500 flows out through the seat body through hole 3051 and the gland through hole 3071.

[0069] Recombination Figure 7 During the normal operation of the water pump, the check valve is in a fully open state, and the first elastic element 304 and the second elastic element 306 are both in a compressed state. The outer diameter of the guide body 400 gradually decreases from front to back. After the fluid passes through the nozzle at the smallest inner diameter of the valve body, the cross-sectional area of ​​the flow channel formed between the guide body 400 and the valve body 100 gradually increases, generating a fluid pressure recovery effect, reducing the water loss through the valve and saving energy.

[0070] like Figure 8 As shown, this is the first stage of the check valve closing state. After the pump is stopped, when the fluid flow or flow rate in the pipeline decreases, the fluid thrust acting on the valve flap 200 also gradually decreases. At this time, the second elastic force of the second elastic element 306 with a larger elastic force will exceed the water flow thrust, and the second elastic element 306 pushes the seat body 305, and the seat body 305 pushes the valve shaft 300 to slide the second sliding distance. The valve flap 200 will complete the first stage of the valve closing stroke at a faster speed to achieve the initial fast closing. However, because the compression length of the second elastic element 306 is set to be short, the second elastic element 306 will return to a free state after the first stage of valve closing, and the valve flap 200 valve closing stroke only reaches about 20% of the total stroke.

[0071] Subsequently, the fluid thrust on the valve disc 200 is further reduced, and the first elastic element 304 continues to push the valve shaft 300 to slide the first sliding distance, thereby pushing the valve disc 200 to complete the second stage of the valve closing stroke, and realizing the servo-type valve closing of the subsequent stroke. When the flow rate in the valve is close to the zero flow rate, the elastic force of the first elastic element 304 is about to be exhausted, and finally the check valve is completed with a servo-type full closure with only a slightly larger elastic force than the fluid thrust, realizing the second stage of zero flow rate valve closing or very close to zero flow rate valve closing. According to the test, the total valve closing time of the check valve in this embodiment is in the range of 0.1 to 1s, and the valve can be closed as soon as possible after the pump is stopped to avoid water hammer backflow.

[0072] The check valve in this embodiment is provided with a first elastic element 304 and a second elastic element 306 at the rear end of the valve shaft 300, and has a built-in series relay-type double elastic force driving structure. Two different and changing spring force servo types are used to cope with the changes in the fluid thrust in the valve body flow channel, thereby realizing the two-stage opening and closing of the check valve. The segmented relay spring strain is used to automatically track the second-stage valve closing at zero flow rate of the water column, successfully eliminating or greatly reducing the valve closing water hammer of the check valve itself, thereby simplifying the transient working condition of water hammer when the pump is stopped, and the structural design is simple and reliable.

[0073] The first elastic element 304 and the second elastic element 306 are pushed or compressed in relay, so that the existing axial flow check valve that can only open and close quickly is transformed into a two-stage opening and closing check valve. During the valve closing process, the second elastic element 306 generates a short-range second elastic force that is stronger than the first elastic element 304, providing a strong thrust for the initial fast closing of the check valve, so that the valve closing process is fast at first and then slow. The valve closing process in the latter stage is relayed by the first elastic element 304 with weaker elastic force but a larger first sliding distance. In the process of decelerating the water column after stopping the pump, under the condition of no back pressure thrust, it can automatically capture the zero flow velocity moment of the water column by relying on its own elastic force to serve the water flow thrust, and close the valve at the critical moment of zero flow velocity or close to zero flow velocity of the water column, so as to not generate its own valve closing water hammer or only generate a small valve closing water hammer; thus, the pump back check valve becomes a water hammer-free check valve or a check valve that generates less water hammer.

[0074] During the two-stage valve opening process, the valve body structure in this embodiment forms a Venturi nozzle effect, generating a large thrust on the front side of the valve flap 200 to overcome the elastic force of the second elastic element 306, so that the valve flap 200 is securely attached to the contact surface of the guide body 400, thereby eliminating the vibration of the valve flap 200, reducing noise and saving space.

[0075] Example 2

[0076] like Figure 3 As shown, the valve body 100 in the check valve provided in this embodiment includes a valve body front section 103 arranged near the liquid inlet 101 and a valve body middle section 104 connected to the valve body front section 103, wherein the inner diameter of the valve body front section 103 is substantially the same from front to back, and a detachable valve seat 600 is connected inside the valve body front section 103. In this embodiment, an external thread is arranged on the outer side of the valve seat 600, and an internal thread is arranged on the inner side of the valve body front section 103, so that the valve seat 600 is connected to the valve body 100 through a thread, and a sealing ring is also arranged between the valve seat 600 and the valve body 100 for sealing. In order to facilitate the installation of the valve seat 600, a plurality of valve seat clamping grooves 603 are arranged on the inner side of the valve seat 600, and the tooling clamp for installation cooperates in the valve seat clamping groove 603, so that the thread of the valve seat 600 is screwed with the thread of the valve body 100.

[0077] The valve seat 600 includes a valve seat front section 601 arranged near the valve seat inlet and a valve seat rear end 602 arranged near the valve seat outlet. The inner diameter of the valve seat front section 601 gradually decreases from front to back, and the inner diameter of the valve seat rear end 602 gradually increases from front to back, so that the valve seat 600 forms a Venturi nozzle effect at the smallest inner diameter.

[0078] In this embodiment, the middle of the body guide 400 is integrally connected to the cantilever 401, and the other end of the cantilever 401 is integrally connected to the valve body 100, so that the body guide 400 and the valve body 100 are integrally formed through the cantilever 401. The cantilever 401 is arranged close to the middle of the body guide 400, which provides better support for the body guide 400. The valve seat 600 and the valve body 100 are detachably connected, so that the valve flap 200 can be installed from the front end of the valve body 100, without disassembling the body guide 400 and then installing the valve flap 200.

[0079] In this embodiment, an elastic sealing ring 201 is provided on the valve flap 200, and when the elastic sealing ring 201 is connected to the valve seat rear end 602, the check valve is closed. The elastic sealing ring 201 forms a soft seal between the valve flap 200 and the valve seat 600, and the sealing effect is better.

[0080] like Figure 4 As shown, in some cases, a first rigid sealing ring 203 is provided on the valve disc 200, and a second rigid sealing ring 604 is correspondingly provided at the rear end 602 of the valve seat, and when the first rigid sealing ring 203 is connected with the second rigid sealing ring 604, the check valve is closed. The first rigid sealing ring 203 and the second rigid sealing ring 604 cooperate to form a hard seal between the valve disc 200 and the valve seat 600, so that the check valve can adapt to more application occasions.

[0081] The other structures, functions and two-stage opening and closing process in this embodiment are consistent with those in Embodiment 1.

[0082] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "left", "right", "up", "down", "top", "bottom", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0083] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0084] The protection scope of the present invention is limited only by the claims. Thanks to the teachings of the present invention, those skilled in the art will easily recognize that alternative structures to the structures disclosed in the present invention can be used as feasible alternative embodiments, and the embodiments disclosed in the present invention can be combined to generate new embodiments, which also fall within the scope of the appended claims.

Claims

1. A two-stage opening and closing axial flow check valve, comprising: A valve body (100) having a valve cavity formed therein, and a liquid inlet (101) and a liquid outlet (102) respectively formed on two sides of the valve body (100) and connected to the valve cavity; a body guide (400) located in the valve cavity and connected to the valve body (100); a contact surface is provided at one end of the body guide (400) close to the liquid inlet (101); A valve flap (200) is located in the valve cavity and is arranged close to a contact surface of the guide body (400), and is capable of reciprocating along an axial center line of the guide body (400) and is used to open and close the check valve; Features: Also includes, A valve shaft (300), one end of which is sleeved in a guide shaft (500) fixed relatively to the guide body (400) and can slide in the guide shaft (500), and the other end of which is connected to the valve flap (200) and drives the valve flap (200) to move; A first elastic element (304), one end of which is connected to one end of the valve shaft (300) located inside the guide shaft (500), and provides a first elastic force and a first sliding distance for the valve shaft (300); A seat body (305) is located in the guide shaft (500) and can slide in the guide shaft (500); and one end of the valve shaft (300) located in the guide shaft (500) can abut against one side of the seat body (305), and the other end of the first elastic element (304) also abuts against the side of the seat body (305); A second elastic element (306), one end of which abuts against the other side of the seat body (305), and the other end of which abuts against a gland (307) fixed relatively to the flow guide body (400); a gland through hole (3071) is provided on the gland (307); the second elastic element (306) provides a second elastic force and a second sliding distance for the valve shaft (300); The elastic coefficients of the first elastic element (304) and the second elastic element (306) are different, and the sum of the first sliding distance and the second sliding distance is the total movement stroke of the valve flap (200) when opening or closing the valve body (100).

2. The two-stage opening and closing axial flow check valve according to claim 1 is characterized in that: The elastic coefficient of the first elastic element (304) is smaller than the elastic coefficient of the second elastic element (306), and the first sliding distance is greater than the second sliding distance.

3. The two-stage opening and closing axial flow check valve according to claim 1 is characterized in that: The seat body (305) comprises a seat body connecting section (3052) and a seat body supporting section (3053) located at one end of the seat body connecting section (3052); one end of the first elastic element (304) connected to the seat body (305) rests on the seat body supporting section (3053); and a seat body through hole (3051) is also provided on the seat body (305).

4. The two-stage opening and closing axial flow check valve according to any one of claims 1 to 3, characterized in that: One end of the valve shaft (300) sleeved in the guide shaft (500) is the valve shaft rear end (302), and a valve shaft accommodating hole (303) is provided inside the valve shaft rear end (302) of the valve shaft (300), the first elastic element (304) is located in the valve shaft accommodating hole (303), and one end of the first elastic element (304) abuts against the bottom of the valve shaft accommodating hole (303), and the valve shaft accommodating hole (303) is connected to the pressure cover through hole (3071).

5. The two-stage opening and closing axial flow check valve according to claim 1 is characterized in that: The valve shaft (300) is threadedly connected to the valve flap (200); one end of the valve shaft (300) connected to the valve flap (200) is also connected to a locking member (308); and a sealing member is also provided on the valve flap (200).

6. The two-stage opening and closing axial flow check valve according to claim 5 is characterized in that: A through hole is provided at the center of the flow guide (400), the guide shaft (500) is fixed in the through hole, and the pressure cover (307) is fixedly connected to the guide shaft (500).

7. The two-stage opening and closing axial flow check valve according to claim 6 is characterized in that: The rear end of the flow guide (400) is integrally connected to a cantilever (401), and the other end of the cantilever (401) is connected to an annular flow guide connecting portion (402), and the flow guide connecting portion (402) is detachably connected to the valve body (100).

8. The two-stage opening and closing axial flow check valve according to claim 6 is characterized in that: The middle portion of the flow guide (400) is integrally connected to the cantilever (401), and the other end of the cantilever (401) is integrally connected to the valve body (100).

9. The two-stage opening and closing axial flow check valve according to claim 7 or 8, characterized in that: The valve body (100) comprises a valve body front section (103) arranged close to the liquid inlet (101) and a valve body middle section (104) connected to the valve body front section (103); the inner diameter of the valve body front section (103) gradually decreases from front to back.

10. The two-stage opening and closing axial flow check valve according to claim 7 or 8, characterized in that: The valve body (100) comprises a valve body front section (103) arranged close to the liquid inlet (101) and a valve body middle section (104) connected to the valve body front section (103); A detachable valve seat (600) is connected to the front section (103) of the valve body. The valve seat (600) includes a front section (601) of the valve seat arranged near the valve seat inlet and a rear end (602) of the valve seat arranged near the valve seat outlet. The inner diameter of the front section (601) of the valve seat gradually decreases from front to back, and the inner diameter of the rear end (602) of the valve seat gradually increases from front to back.

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