Two-stage opening and three-stage closing axial flow type check valve

Abstract

The utility model discloses an axial flow type check valve opened in two stages and closed in three stages, and belongs to the technical 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, the two different and variable elastic elements are used for coping with changes of fluid thrust in a valve body flow channel in a servo mode, and two-stage valve opening of the check valve is achieved. When the valve is closed, on the basis that two-stage valve closing is achieved through the first elastic element and the second elastic element, the damping assembly is arranged, and three-stage valve closing is achieved. In the three-stage valve closing process, the stroke is short, only a tiny valve closing water hammer opposite to the pump stopping water hammer is generated, the peak value of the positive water hammer after the pump stopping water hammer is overlapped with the valve closing water hammer is reduced, and the valley value of the first-phase negative water hammer after pump stopping is increased or not reduced at least. Therefore, the positive water hammer peak value of the pump stopping first-phase negative water hammer reflected wave is indirectly reduced or at least not increased.

Description

Technical Field

[0001] The utility model relates to the technical field of check valves, and more specifically to an axial flow check valve with two-stage opening and three-stage closing. 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] In order to reduce the valve closing water hammer generated after the valve is closed, the existing check valve adopts a slow closing method, using the large damping of the hydraulic cylinder to slow close the valve. In this method, the slow closing degree of the valve closing usually reaches 20% to 30% or even 40% of the total stroke. For example, the valve disc first closes 75% of the stroke quickly, and then slowly closes 25% of the stroke. The slow closing time is as long as 5 to 120 seconds, and the ratio of slow closing to fast closing stroke reaches a 28-open level. The purpose of the slow closing of the check valve is to release water and reduce pressure, aiming to reduce or eliminate the reflected wave of the pump stop water hammer - the positive water hammer peak, but the large slow closing stroke reserved in advance may even aggravate the backflow of the water column, and the valve closing water hammer will inevitably be generated after the valve is closed, creating a second water hammer source in addition to the pump stop water hammer.

[0004] For example, Chinese patent CN108167523A discloses a slow-closing check valve, including a valve body, a valve plate placed inside the valve seat fixed to the inner cavity of one side of the valve body, a positioning rod provided in the valve body, a through cavity provided along the axis of the positioning rod, the other end of the positioning rod slidably connected to the damping piston, a valve plate spring provided on the outer wall of the positioning rod, a deep hole provided at the end of the damping piston away from the reset spring, a cross-shaped medium discharge hole provided on the side wall corresponding to the position of the deep hole, and a flow storage hole connected to the deep hole provided along the axis direction on the side where the damping piston contacts the reset spring. This scheme realizes the damping of the closing movement of the valve plate through the coordination of the structure and the mutual adjustment of a series of damping movements of the piston, but the damping slow-closing stroke in this scheme is relatively large, which is not conducive to reducing the generation of valve closing water hammer. Summary of the invention

[0005] The utility model provides an axial flow check valve with two-stage opening and three-stage closing, which further shortens the slow closing stroke of the final valve closing, realizes three-stage valve closing, can release pressure in time, and avoids or reduces the generation of valve closing water hammer.

[0006] In order to achieve the above-mentioned purpose, the technical solution provided by the utility model is:

[0007] An axial flow check valve with two-stage opening and three-stage closing, comprising:

[0008] 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;

[0009] 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;

[0010] 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;

[0011] Also includes,

[0012] 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 passes through the valve flap. When the valve shaft slides, it drives the valve flap to move to correspondingly open or close the check valve;

[0013] 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;

[0014] 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;

[0015] 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, and 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;

[0016] The damping assembly is located at the liquid inlet and has a damping liquid storage chamber therein. It also includes a slidable piston and a third elastic element located in the damping liquid storage chamber. One side of the piston can compress the damping liquid storage chamber and is connected to the third elastic element, and the other end extends out of the damping assembly. During the final process of closing the valve, the piston can contact one end of the valve shaft passing through the valve disc and provide a damping force for the valve shaft. At the same time, the piston slides, and the volume of the damping liquid storage chamber can change during the sliding of the piston.

[0017] Furthermore, during the valve closing process, the valve closing stroke after the valve shaft abuts against the piston is the slow closing stroke of the check valve; in the third stage slow closing stroke of the valve closing, the valve shaft drives the valve disc to complete the valve closing under the action of the damping assembly and the first elastic element, and the third stage slow closing stroke is 3%-10% of the total valve closing stroke.

[0018] Further, 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.

[0019] Furthermore, the damping assembly includes a cylinder body fixedly arranged relative to the valve body and a cylinder cover connected to the cylinder body, one end of the piston is located in the cylinder body and the other end passes through the cylinder cover, a throttling hole is provided on the piston, and an inlet and outlet liquid hole is provided on the cylinder cover.

[0020] Furthermore, a seat through hole is provided on the seat body;

[0021] The seat body comprises 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 abuts against the seat body supporting section.

[0022] Furthermore, one end of the valve shaft sleeved in the guide shaft is the rear end of the valve shaft, a valve shaft accommodating hole is opened inside the rear end 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.

[0023] Furthermore, 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 ring is also provided on the valve disc.

[0024] Furthermore, the rear end of the flow guide is integrally connected to a cantilever, the other end of the cantilever is connected to an annular flow guide connecting portion, and the flow guide connecting portion is detachably connected to the valve body;

[0025] Or the middle part of the flow guide is integrally connected to a cantilever, and the other end of the cantilever is integrally connected to the valve body;

[0026] 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.

[0027] Furthermore, the valve body includes a valve body front section arranged near 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; the cylinder body is located on the bracket, the bracket is located in the liquid inlet, and the bracket is detachably connected to the valve body front section.

[0028] Furthermore, the valve body comprises a valve body front section arranged close to the liquid inlet and a valve body middle section connected to the valve body front section;

[0029] 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; the cylinder body is located on the bracket, the bracket is located in the liquid inlet, and the bracket is integrally connected to the valve seat.

[0030] Compared with the prior art, the technical solution provided by the utility model has the following beneficial effects: the utility model sets a first elastic element and a second elastic element at the rear end of the valve shaft, and the first elastic element and the second elastic element form a series relay type double elastic force driving structure, and utilizes two different and changing elastic elements to servo-type to cope with the change of fluid thrust in the valve body flow channel, so as to realize the two-stage valve opening of the check valve. When closing the valve, a damping component is set on the basis of the two-stage valve closing achieved by the first elastic element and the second elastic element, so as to realize the three-stage valve closing. During the three-stage valve closing process, the stroke is short, and only a small valve closing water hammer in the opposite direction of the pump stopping water hammer is generated, which not only reduces the positive water hammer peak value after the pump stopping water hammer is superimposed on the valve closing water hammer, but also raises or at least does not reduce the trough value of the first phase negative water hammer after the pump stopping, thereby indirectly reducing or at least not increasing the positive water hammer peak value of the first phase negative water hammer reflection wave of the pump stopping. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the check valve structure of Example 1;

[0032] Figure 2 for Figure 1 A schematic diagram of the structure of the check valve at position A;

[0033] Figure 3 It is a schematic diagram of the enlarged structure of the damping component;

[0034] Figure 4 This is a schematic diagram of the check valve structure of Example 2;

[0035] Figure 5 This is a schematic diagram of the check valve structure in another case in Example 2;

[0036] Figure 6 This is a schematic diagram of the closed state of the check valve in Example 1;

[0037] Figure 7 This is a schematic diagram of the first stage opening state of the check valve in Example 1;

[0038] Figure 8 This is a schematic diagram of the fully open state of the check valve in Example 1;

[0039] Fig. 9 This is a schematic diagram of the first stage closing state of the check valve in Example 1;

[0040] Fig.10This is a schematic diagram of the check valve in the second stage of closing state of Example 1;

[0041] Fig.11 This is a schematic diagram of the third stage closing state of the check valve in Example 1.

[0042] Description of labels:

[0043] 100, valve body; 101, liquid inlet; 102, liquid outlet; 103, front section of valve body; 104, middle section of valve body;

[0044] 200, valve disc; 201, elastic sealing ring; 202, first rigid sealing ring;

[0045] 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;

[0046] 400, flow guide body; 401, cantilever; 402, flow guide body connection part;

[0047] 500, guide shaft;

[0048] 600, valve seat; 601, front section of valve seat; 602, rear end of valve seat; 603, valve seat slot; 604, bracket; 605, mounting slot; 606, second rigid sealing ring;

[0049] 700, damping assembly; 701, cylinder body; 702, third elastic element; 703, piston; 7031, throttle hole; 704, cylinder head; 7041, liquid inlet and outlet holes. DETAILED DESCRIPTION

[0050] 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.

[0051] In the water pump pressurized pipeline system, especially in the pipeline with large static height difference or in the pipeline near the water pump station, the water column deceleration acceleration is very large after the pump is stopped, and the water column deceleration time is very short, and the water column will quickly flow back due to the high back pressure. The axial flow check valve behind the pump may close the valve during the rapid backflow process, thereby generating its own valve closing water hammer, which will be superimposed on the pump stop water hammer, forming a positive water hammer peak with a water hammer phase of 0.1 to 0.6s (while the pump stop water hammer phase is several seconds to tens of seconds), and its peak value rise is several meters to tens of meters, and sometimes it will exceed the 30-50% relative rise specified in the standard. In this case, it is difficult to release water and reduce pressure in time using the existing ordinary fast-closing axial flow check valve.

[0052] The utility model provides an axial flow check valve with two-stage opening and three-stage closing. In the last stage of valve closing slow closing, a damping component is used to realize valve closing in the third stage, thereby eliminating or greatly reducing the valve closing water hammer of the check valve itself and simplifying the transient working condition of pump stopping water hammer.

[0053] Example 1

[0054] 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 .

[0055] 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.

[0056] 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 point where the inner diameter is the smallest, and a nozzle is formed at this point, which can reduce water loss through the valve.

[0057] 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.

[0058] 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.

[0059] The check valve in this embodiment further includes a valve shaft 300 , a seat body 305 , a first elastic element 304 , a second elastic element 306 and a damping assembly 700 .

[0060] 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 disc 200 and passes through the valve disc 200. When the valve shaft 300 slides, it drives the valve disc 200 to move to open or close the check valve accordingly. 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 be connected to the valve disc 200. When the valve shaft 300 slides back and forth in the guide shaft 500, it synchronously drives the valve disc 200 to move back and forth, 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 a valve disc through hole is provided at the center of the valve disc 200. The valve shaft front end 301 passes through the valve disc through hole and is connected to the valve shaft 300. Furthermore, the inner side wall of the valve flap through hole is provided with an internal thread, and the front end 301 of the valve shaft is provided with an external thread, so that the valve shaft 300 and the valve flap 200 are connected by threads, 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.

[0061] 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.

[0062] 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.

[0063] 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 .

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] Combination Figure 1 and Figure 3As shown, the damping assembly 700 is arranged at the liquid inlet 101, and has a damping liquid storage chamber therein. The damping assembly 700 also includes a slidable piston 703 and a third elastic element 702 located in the damping liquid storage chamber. One side of the piston 703 can compress the damping liquid storage chamber and is connected to the third elastic element 702, and the other end extends out of the damping assembly 700; in the final process of closing the valve, the piston 703 can contact one end of the valve shaft 300 passing through the valve disc 200 and provide a damping force for the valve shaft 300, while the piston 703 slides, and the volume of the damping liquid storage chamber can change during the sliding process of the piston 703. Specifically, the damping assembly 700 includes a cylinder body 701 fixedly arranged relative to the valve body 100, and a cylinder head 704 connected to the cylinder body 701. One end of the piston 703 is located in the cylinder body 701, and the other end passes through the cylinder head 704. The damping liquid storage chamber is located between the bottom of the cylinder body 701 and the piston 703. In addition, the piston 703 and the valve shaft 300 are located on the same axis. A throttle hole 7031 is provided on the piston 703, and a liquid inlet and outlet hole 7041 is provided on the cylinder cover 704.

[0072] In this embodiment, the cylinder body 701 is located on the bracket 604, the bracket 604 is located in the liquid inlet 101 and is fixedly arranged relative to the valve body 100, and the bracket 604 is detachably connected to the front section 103 of the valve body. Specifically, one end of the bracket 604 connected to the valve body 100 has an annular connecting portion, and the outer side of the connecting portion is provided with a thread, and the inner side of the liquid inlet 101 is also provided with a thread to cooperate with the connecting portion to achieve the detachable connection between the bracket 604 and the front section 103 of the valve body 100. The center of the bracket 604 is provided with a mounting slot 605, and the cylinder body 701 is installed in the mounting slot 605. One fixing method of the cylinder body 701 is that the bolt passes through the bottom of the mounting slot 605 and is fixedly connected to the cylinder body 701. Moreover, a gasket and other components can be arranged between the cylinder body 701 and the bottom of the mounting slot 605 to adjust the position of the damping assembly 700 relative to the valve shaft 300.

[0073] The cylinder body 701 is connected to the cylinder cover 704 by screws, and the piston 703 is arranged in the cylinder body 701. The piston 703 includes a piston rod and a piston ring circumferentially arranged on the outer side of the piston rod, and the outer side of the piston ring slides along the inner side of the cylinder body 701. The throttle hole 7031 is located on the piston ring, one end of the piston rod is sleeved with the third elastic element 702, and the other end passes through the cylinder cover 704, and the other end of the third elastic element 702 abuts against the bottom of the cylinder body 701.

[0074] In the final stage of closing the valve, the valve shaft 300 moves toward the liquid inlet 101 to contact the piston 703 and exerts a thrust on the piston 703. The piston 703 moves toward the bottom of the cylinder 701 to compress the damping liquid storage chamber. The volume of the damping liquid storage chamber gradually decreases, and the medium in the damping liquid storage chamber slowly flows out through the throttle hole 7031 to form a damping effect. At the same time, the third elastic element 702 exerts a thrust on the piston 703. The damping effect of the throttle hole 7031 and the thrust of the third elastic element 702 form the damping force of the damping assembly 700 on the valve shaft 300. During the valve opening process, the thrust on the piston 703 disappears, and the elastic force of the third elastic element 702 pushes the piston 703 to move, so that the piston 703 is reset, and the volume of the damping liquid storage chamber is restored to the initial state.

[0075] In this embodiment, the elastic coefficients of the first elastic element 304 and the second elastic element 306 are different. Specifically, 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. When closing the valve, in the final stage of closing the valve, the valve closing stroke after the valve shaft 300 abuts against the piston 703 is the third stage slow closing stroke of the check valve. In the slow closing stroke of closing the valve, the valve shaft 300 drives the valve disc 200 to complete the valve closing under the action of the damping assembly 700 and the first elastic element 304, and the third stage slow closing stroke is 3%-10% of the total valve closing stroke.

[0076] 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 three-stage closing, the operation process of the check valve of this embodiment will be further explained.

[0077] like Figure 6 As 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 disc 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 valve shaft 300 pushes the piston 703 to move toward the bottom of the cylinder body 701 to the point closest to the bottom of the cylinder body 701, and the piston 703 moves its maximum stroke. In this state, the first elastic element 304 is in the initial compression state, the second elastic element 306 is in the free state, and the third elastic element 702 is in the maximum compression state.

[0078] like Figure 7 As shown, the check valve is in 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.

[0079] like Figure 8 As shown in the figure, the valve is fully open after the second stage of the check valve is opened. Figure 7 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 in 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.

[0080] 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.

[0081] Recombination Figure 8 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.

[0082] like Fig. 9 As shown, it is the first stage of the check valve closing state. After stopping the pump, when the fluid flow or flow rate in the pipeline decreases, the fluid thrust acting on the valve disc 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 will push the seat body 305, and the seat body 305 will push the valve shaft 300 to slide the second sliding distance. The valve disc 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 the valve closing.

[0083] 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, 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 zero flow rate, the elastic force of the first elastic element 304 is about to be exhausted, and finally the check valve completes the subsequent servo-type full closure with only an elastic force slightly greater than the fluid thrust. According to tests, when the check valve is not provided with a damping component 700, the total valve closing time is ≤1s. In some cases, the valve closing speed is too fast to release water and reduce pressure in time. Fig.10 As shown, after the second stage of the valve closing stroke, the valve shaft 300 abuts against the piston 703, and the valve disc completes the subsequent slow closing stroke. During this process, the valve disc completes the last 3% to 10% of the valve closing stroke under the action of the damping component 700 and the first elastic element 304, thereby completing the third stage of the slow closing valve, until the check valve is fully closed, as shown in FIG. Fig.11 The state shown in . Through experiments, it is found that the damping assembly 700 is set, and the slow closing time is 1 to 6 seconds, which can achieve a small damping slow closing of the last stroke of the check valve disc; compared with the conventional axial flow check valve with a large slow closing stroke of 20 to 40% and a long slow closing time of 5 to 120 seconds, it is almost an order of magnitude or more different. The check valve in this embodiment can effectively release water and reduce pressure in time.

[0084] 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 a series relay type double elastic force driving structure is built in the stroke, and two different and changing spring force servo types are used to respond to the change of fluid thrust in the valve body flow channel to realize the two-stage opening of the check valve. During the valve closing process, the second elastic element 306 realizes the first stage of valve closing, and the first elastic element 304 relays to realize the second stage of valve closing. At the end of the second stage of valve closing, the valve shaft 300 abuts against the piston 703, and the damping assembly 700 provides a damping force for the valve shaft 300, and the third stage of slow closing of the valve begins. During the third stage of slow closing of the valve, the valve shaft 300 completes the final damping valve closing stage under the combined action of the damping force and the elastic force of the first elastic element 304. The slow closing stroke of the final damping valve is only 3% to 10% of the total valve closing stroke, which can release water and reduce pressure in time. In the final stage of valve closing, only a small flow can flow back, resulting in a small valve closing water hammer. The phase of the valve closing water hammer is opposite to the pump stopping water hammer, which can reduce the pump stopping water hammer.

[0085] 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.

[0086] Example 2

[0087] like Figure 4 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] like Figure 5 As shown, in some cases, a first rigid sealing ring 202 is provided on the valve disc 200, and a second rigid sealing ring 606 is correspondingly provided at the rear end 602 of the valve seat, and when the first rigid sealing ring 202 is connected with the second rigid sealing ring 606, the check valve is closed. The first rigid sealing ring 202 and the second rigid sealing ring 606 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.

[0092] In this embodiment, the bracket 604 is integrally connected to the valve seat 600 , and the arrangement of the bracket 604 is more convenient.

[0093] The other structures, functions and two-stage opening and closing process in this embodiment are consistent with those in Embodiment 1.

[0094] 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.

[0095] 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.

[0096] 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. An axial flow check valve with two-stage opening and three-stage closing, 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 passes through the valve flap (200). When the valve shaft (300) slides, it drives the valve flap (200) to move so as to correspondingly open or close the check valve; A first elastic element (304), one end of which 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 for the valve shaft (300); a seat body (305), which 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), and 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 damping assembly (700) is located at the liquid inlet (101), and has a damping liquid storage chamber therein, and also includes a slidable piston (703) and a third elastic element (702) located in the damping liquid storage chamber. One side of the piston (703) can compress the damping liquid storage chamber and is connected to the third elastic element (702), and the other end extends out of the damping assembly (700); in the final process of closing the valve, the piston (703) can contact one end of the valve shaft (300) passing through the valve disc (200) and provide a damping force for the valve shaft (300), while the piston (703) slides, and the volume of the damping liquid storage chamber can change during the sliding process of the piston (703).

2. The two-stage opening and three-stage closing axial flow check valve according to claim 1, characterized in that: During the valve closing process, the valve closing stroke after the valve shaft (300) abuts against the piston (703) is the third stage slow closing stroke of the check valve; in the slow closing stroke of the valve closing, the valve shaft (300) drives the valve flap (200) to complete the valve closing under the action of the damping assembly (700) and the first elastic element (304), and the third stage slow closing stroke is 3%-10% of the total valve closing stroke.

3. The two-stage opening and three-stage closing axial flow check valve according to claim 1 or 2, 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.

4. The two-stage opening and three-stage closing axial flow check valve according to claim 1 or 2, characterized in that: The damping assembly (700) comprises a cylinder body (701) fixedly arranged relative to the valve body (100) and a cylinder cover (704) connected to the cylinder body (701); one end of the piston (703) is located in the cylinder body (701) and the other end passes through the cylinder cover (704); a throttling hole (7031) is provided on the piston (703), and a liquid inlet and outlet hole (7041) is provided on the cylinder cover (704).

5. The two-stage opening and three-stage closing axial flow check valve according to claim 4 is characterized in that: The seat body (305) is also provided with a seat body through hole (3051); 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), and one end of the first elastic element (304) connected to the seat body (305) abuts against the seat body supporting section (3053).

6. The two-stage opening and three-stage closing axial flow check valve according to claim 5, 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).

7. The two-stage opening and three-stage closing axial flow check valve according to claim 4, 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 ring is also provided on the valve flap (200).

8. The two-stage opening and three-stage closing axial flow check valve according to claim 7, 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); Or the middle part 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); 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).

9. The two-stage opening and three-stage closing axial flow check valve according to claim 8, characterized in that: The valve body (100) comprises 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); the inner diameter of the valve body front section (103) gradually decreases from front to back; the cylinder body (701) is located on the bracket (604), the bracket (604) is located in the liquid inlet (101), and the bracket (604) and the valve body front section (103) are detachably connected.

10. The two-stage opening and three-stage closing axial flow check valve according to claim 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, and 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; the cylinder body (701) is located on the bracket (604), the bracket (604) is located in the liquid inlet (101), and the bracket (604) is integrally connected to the valve seat (600).

Images