Dual valve

Abstract

The dual valve comprises a valve body, an upper valve bonnet, a lower valve bonnet, a valve element assembly and a valve seat assembly, the valve element assembly comprises a lower valve rod arranged in the lower valve bonnet, a sliding block is arranged at one end of the lower valve rod, and a valve element is arranged at the end, close to the sliding block, of the lower valve rod; a sliding groove is formed in the valve element, and the sliding block can slide in the sliding groove to enable the valve element to move in the direction of the center line of the lower valve rod, when the valve is opened, the valve element is separated from the first sealing piece firstly and then moves in the direction away from the valve body, and when the valve is closed, the valve element is separated from the first sealing piece and then moves in the direction away from the valve body. The valve element firstly makes contact with the valve body and then moves towards the first sealing piece to extrude the first sealing piece, friction between the valve element and the first sealing piece is reduced, and therefore abrasion between the valve element and the first sealing piece when the valve body is opened and closed is reduced, the service life of the valve is further prolonged, and the risk of leakage caused by abrasion of the sealing piece is reduced. And meanwhile, a worker can be prompted when the valve leaks.

Description

Technical Field

[0001] The present invention relates to the technical field of double valves, and more specifically, to a double valve. Background Art

[0002] In the application scenarios of instrument valves or process valves, the double valve plays a vital role of double insurance. The double valve is usually composed of two identical or similar valves, which can work together through special design and connection methods. When one of the valves fails or leaks, the other valve can immediately take over to ensure the normal operation of the system and effectively avoid safety accidents such as system shutdown and leakage caused by single valve failure. This double insurance design greatly improves the reliability and stability of the system, and is especially suitable for industries such as chemical, petroleum, and natural gas that have extremely high requirements for safety and continuity.

[0003] However, in the prior art, when the valve body is opened and closed, the valve stem drives the valve core to rotate synchronously, which will cause certain wear on the valve seal. When the valve core is about to leave and clamp the seal, the seal and the valve core are in close contact and relatively displaced, which greatly increases the degree of wear on the seal, affects the service life, and increases the resistance to the rotation of the handle when the valve is opened.

[0004] Furthermore, although the double valve effectively prevents safety accidents caused by leakage of a single valve through double insurance, when one of the valve cores of the double valve leaks, the entire double valve may leak if it is not repaired in time. The existing double valve cannot provide reminders to the staff, and there is no emergency remedial measure when a single valve core of the double valve leaks. Therefore, the present invention proposes a double valve to solve the above problem. Summary of the invention

[0005] In order to overcome the above defects of the prior art, an embodiment of the present invention provides a double valve to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a double valve, comprising: a valve body, an upper valve bonnet, a lower valve bonnet, a valve core assembly and a valve seat assembly, the valve core assembly comprising a lower valve stem arranged inside the lower valve bonnet, a slider being arranged at one end of the lower valve stem, a valve core being arranged at one end of the lower valve stem close to the slider, a slide groove being provided inside the valve core, the slider being able to slide inside the slide groove to move the valve core toward the center line direction of the valve stem; the valve seat assembly comprising a first sealing member arranged inside the valve body, the first sealing member being able to cooperate with the valve core to seal the valve body, the valve seat assembly also comprising a detection member arranged inside the valve body, when the valve body leaks, the detection member being able to float due to the medium pressure, thereby increasing the internal pressure of the first sealing member to squeeze the valve core.

[0007] Preferably, a wedge block is fixedly connected to one end of the lower valve stem close to the valve body, the wedge block is fixedly connected to the slider, and there are at least two valve cores which are symmetrically distributed along the central axis of the lower valve stem.

[0008] Preferably, the end of the lower valve stem close to the wedge block is fixedly connected to a first piston plate, and the first piston plate is slidably connected to the inner wall of the lower valve bonnet. When the valve is opened, the first piston plate can squeeze the internal gas of the lower valve bonnet, and a third exhaust hole is opened on the inner wall of the lower valve bonnet.

[0009] Preferably, an energy storage tank is provided inside the valve body, a first air inlet is provided inside the energy storage tank, a one-way valve and a relief valve are provided at the first air inlet, and a first exhaust hole is provided inside the energy storage tank.

[0010] Preferably, the valve core assembly also includes an upper valve stem arranged inside the upper valve bonnet, one end of the upper valve stem is fixedly connected to a connecting column, a connecting groove is provided inside the connecting column, one end of the lower valve stem away from the wedge block is fixedly connected to a connecting disk, the connecting disk and the connecting groove are slidably connected, the connecting column and the inner wall of the upper valve bonnet are slidably connected, and the end of the upper valve stem away from the lower valve stem passes through the upper valve bonnet and is threadedly connected to the upper valve bonnet.

[0011] Preferably, the end of the connecting column away from the lower valve stem is fixedly connected to a second piston plate, the second piston plate is slidably connected to the upper valve cap, the inner wall of the upper valve cap is provided with a second air inlet hole and a second exhaust hole, and the second exhaust hole is connected to the first air inlet hole of the energy storage tank.

[0012] Preferably, a detection groove is opened inside the valve body, a detection hole is opened at the bottom of the detection groove, the detection piece can seal the detection hole, a third piston plate is slidably connected inside the detection groove, an end of the third piston plate away from the detection piece is fixedly connected to a warning column, a first elastic piece is arranged in the detection groove, one end of the first elastic piece is fixedly connected to the inner wall of the detection groove, and the other end of the first elastic piece is fixedly connected to an end of the third piston plate close to the warning column.

[0013] Preferably, a limiting groove is provided inside the valve body, a limiting column is slidably connected inside the limiting groove, the limiting groove is connected to the third exhaust hole, the limiting groove is connected to the detection groove, and the limiting column can limit the third piston plate by sliding.

[0014] Preferably, a sealing groove is opened inside the valve body, and a second sealing member is slidably connected inside the sealing groove. The sealing groove is connected to the detection groove through a pipeline, and a through hole is opened at one end of the second sealing member. The second sealing member can slide to connect the first exhaust hole with the first sealing member through the through hole.

[0015] Preferably, there are two lower valve caps which are fixedly connected to two ends of the same side of the valve body, and there are two upper valve caps, one end of each upper valve cap is fixedly connected to one end of the corresponding lower valve cap away from the valve body.

[0016] Technical effects and advantages of the present invention: 1. The present invention reduces the wear between the valve core and the first sealing member due to relative rotation by having the lower valve stem only follow the upper valve stem in linear motion, thereby increasing the service life of the double valve and reducing the resistance when opening and closing the valve, making the valve open and close more smoothly.

[0017] 2. In the present invention, when the valve is opened, the valve core is first separated from the first sealing member and then moves away from the valve body. When the valve is closed, the valve core first contacts the valve body and then moves toward the first sealing member to squeeze the first sealing member, thereby reducing the friction between the valve core and the first sealing member, thereby reducing the wear between the valve core and the first sealing member when the valve body is opened and closed, further increasing the service life of the valve and reducing the risk of leakage due to wear of the sealing member.

[0018] 3. The present invention provides a warning to the staff by extending the warning column out of the valve body, and at the same time increases the internal pressure of the first sealing member to enhance the sealing between the first sealing member and the valve core, thereby preventing the staff from being unable to receive timely warnings when one of the valve cores of the valve leaks due to wear, and avoiding more serious safety accidents or greater losses due to the lack of emergency measures for the valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0020] Figure 2 It is a cross-sectional view of the overall structure of the present invention in a closed state.

[0021] Figure 3 For the present invention Figure 2 A-section structure enlarged view.

[0022] Figure 4 For the present invention Figure 2 Enlarged view of the structure of part B.

[0023] Figure 5 It is a cross-sectional view of the energy storage tank and sealing tank structure of the present invention.

[0024] Figure 6 This is a cross-sectional view of the first sealing structure of the present invention.

[0025] Figure 7 It is a sectional view of the overall structure of the upper valve stem of the present invention.

[0026] Figure 8It is a schematic diagram of the overall structure of the lower valve stem of the present invention.

[0027] Fig. 9 It is a schematic diagram of the overall structure of the valve core of the present invention.

[0028] Fig.10 This is a cross-sectional view of the overall structure of the present invention in an opened state.

[0029] The accompanying drawings are marked as follows: 1. valve body; 11. energy storage tank; 111. first air inlet; 112. first exhaust hole; 12. limiting groove; 121. limiting column; 2. upper valve bonnet; 21. second air inlet; 22. second exhaust hole; 3. lower valve bonnet; 31. third exhaust hole; 4. valve core assembly; 41. lower valve stem; 411. wedge block; 412. first piston plate; 413. connecting plate; 42. slider; 43. valve core; 431. slide groove; 44. upper valve stem; 441. connecting column; 442. connecting groove; 443. second piston plate; 5. valve seat assembly; 51. first sealing member; 52. detection member; 53. detection groove; 531. detection hole; 532. first elastic member; 54. third piston plate; 541. warning column; 55. sealing groove; 551. second sealing member. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Embodiment 1 In the actual production process, when the valve body 1 is switched, the valve stem drives the valve core to rotate synchronously, which will cause certain wear on the valve seal, affecting the service life and increasing the resistance to the rotation of the handle. This embodiment is specially invented to solve the above problems.

[0032] See also Figures 1 to 10 As shown, a double valve according to an embodiment of the present invention comprises a valve body 1, an upper valve cap 2, a lower valve cap 3, a valve core assembly 4 and a valve seat assembly 5. The valve core assembly 4 comprises a lower valve stem 41 arranged inside the lower valve cap 3, a slider 42 being arranged at one end of the lower valve stem 41, and a valve core 43 being arranged at one end of the lower valve stem 41 close to the slider 42. Fig. 9As shown, a slide groove 431 is opened inside the valve core 43, and the slider 42 can slide inside the slide groove 431 to move the valve core 43 toward the center line direction of the lower valve stem 41; the valve seat assembly 5 includes a first sealing member 51 arranged inside the valve body 1, and the first sealing member 51 can cooperate with the valve core 43 to seal the valve body 1. The valve seat assembly 5 also includes a detection member 52 arranged inside the valve body 1. When the valve body 1 leaks, the detection member 52 can float due to the medium pressure, thereby increasing the internal pressure of the first sealing member 51 to squeeze the valve core 43, wherein the outer wall of the first sealing member 51 is an elastic material.

[0033] See also Figure 2 and Figure 3 As shown, one end of the lower valve stem 41 close to the valve body 1 is fixedly connected with a wedge block 411, the wedge block 411 is fixedly connected to the slider 42, there are at least two valve cores 43 and they are symmetrically distributed along the central axis of the lower valve stem 41, one end of the lower valve stem 41 close to the wedge block 411 is fixedly connected with a first piston plate 412, the first piston plate 412 is slidably connected to the inner wall of the lower valve cap 3, when the valve is opened, the first piston plate 412 can squeeze the internal gas of the lower valve cap 3, and the inner wall of the lower valve cap 3 is provided with a third exhaust hole 31.

[0034] See also Figure 5 As shown, an energy storage tank 11 is provided inside the valve body 1 , a first air inlet 111 is provided inside the energy storage tank 11 , a one-way valve and a relief valve are provided at the first air inlet 111 , and a first exhaust hole 112 is provided inside the energy storage tank 11 .

[0035] See also Figure 2 and Figure 7 As shown, the valve core assembly 4 also includes an upper valve stem 44 disposed inside the upper valve cap 2, one end of the upper valve stem 44 is fixedly connected to a connecting column 441, and a connecting groove 442 is provided inside the connecting column 441. Figure 8 As shown, the end of the lower valve stem 41 away from the wedge block 411 is fixedly connected with a connecting plate 413, the connecting plate 413 and the connecting groove 442 are slidably connected, the connecting column 441 and the inner wall of the upper valve bonnet 2 are slidably connected, the end of the upper valve stem 44 away from the lower valve stem 41 passes through the upper valve bonnet 2 and is threadedly connected to the upper valve bonnet 2, the end of the connecting column 441 away from the lower valve stem 41 is fixedly connected with a second piston plate 443, the second piston plate 443 is slidably connected to the upper valve bonnet 2, the inner wall of the upper valve bonnet 2 is provided with a second air inlet hole 21 and a second exhaust hole 22, the second exhaust hole 22 is communicated with the first air inlet hole 111 of the energy storage tank 11, and the end of the upper valve stem 44 away from the connecting column 441 is fixedly connected with a handle.

[0036] See also Figure 2 and Figure 4As shown, a detection groove 53 is opened inside the valve body 1, and a detection hole 531 is opened at the bottom of the detection groove 53. The detection member 52 can seal the detection hole 531. A third piston plate 54 is slidably connected inside the detection groove 53, and an end of the third piston plate 54 away from the detection member 52 is fixedly connected to a warning column 541. A first elastic member 532 is arranged in the detection groove 53, and one end of the first elastic member 532 is fixedly connected to the inner wall of the detection groove 53, and the other end of the first elastic member 532 is fixedly connected to an end of the third piston plate 54 close to the warning column 541.

[0037] See also Figure 4 As shown, a limiting groove 12 is opened inside the valve body 1, and a limiting column 121 is slidably connected inside the limiting groove 12. The limiting groove 12 is connected to the third exhaust hole 31, and the limiting groove 12 is connected to the detection groove 53. The limiting column 121 can limit the third piston plate 54 by sliding.

[0038] See also Figure 5 As shown, a sealing groove 55 is opened inside the valve body 1, and a second sealing member 551 is slidably connected inside the sealing groove 55. The sealing groove 55 is connected with the detection groove 53 through a pipeline. A through hole is opened at one end of the second sealing member 551. The second sealing member 551 can slide to connect the first exhaust hole 112 with the first sealing member 51 through the through hole.

[0039] See also Fig.10 As shown, there are two lower valve bonnets 3 and they are fixedly connected to the two ends of the same side of the valve body 1 respectively, there are two upper valve bonnets 2, one end of each upper valve bonnet 2 is fixedly connected to the corresponding end of the lower valve bonnet 3 away from the valve body 1, a sealing gasket is arranged between the upper valve bonnet 2 and the lower valve bonnet 3, and a locking nut is arranged at the end of the lower valve bonnet 3 away from the valve body 1, and the locking nut is threadedly connected to the upper valve bonnet 2 for locking the upper valve bonnet 2.

[0040] When in use, when the valve is opened from a closed state, the handle is turned to drive the upper valve stem 44 to rotate inside the upper valve cap 2, so that the upper valve stem 44 moves in a direction away from the valve body 1, so that the lower valve stem 41 drives the valve core 43 to move in a direction away from the valve body 1, and the valve core 43 no longer squeezes the first sealing member 51, and the valve is opened. Conversely, when the valve is closed from an open state, the handle is turned in the opposite direction so that the upper valve stem 44 drives the lower valve stem 41 to move in a direction close to the valve body 1, so that the valve core 43 moves downward and squeezes the first sealing member 51, and the valve is closed. Since the upper valve stem 44 and the lower valve stem 41 are rotationally connected via the connecting groove 442 and the connecting plate 413, the lower valve stem 41 only follows the upper valve stem 44 to make a linear motion, thereby reducing the wear between the valve core 43 and the first sealing member 51 due to relative rotation.

[0041] Embodiment 2 It is found in actual use that when the valve body 1 is switched, when the valve core 43 leaves and squeezes the first sealing member 51, the valve core 43 still causes significant wear to the first sealing member 51 due to the close contact between the valve core 43 and the first sealing member 51. Therefore, further improvements are made on the basis of the above embodiments.

[0042] On the basis of the above embodiment, in use, when the valve is opened from a closed state, the handle is rotated so that the upper valve stem 44 drives the lower valve stem 41 to move away from the valve body 1, thereby causing the lower valve stem 41 to drive the wedge block 411 to move away from the valve body 1, and the movement of the wedge block 411 drives the slider 42 to slide inside the slide groove 431 of the valve core 43, thereby causing the valve core 43 to move toward the center line direction of the lower valve stem 41, thereby causing the valve core 43 to no longer contact the first sealing member 51, and when the slider 42 moves to the limit position, the handle is continued to be rotated so that the slider 42 drives the valve core 43 to move away from the valve body 1, thereby causing the valve to be opened, and conversely, when the valve is closed from an open state, the handle is rotated so that the upper valve stem 44 drives the lower valve stem 41 ... The valve core 43 moves in the direction close to the valve body 1, thereby causing the valve core 43 to move in the direction close to the valve body 1. When the valve core 43 moves to contact with the valve body 1, the handle is continued to be turned so that the wedge block 411 drives the slider 42 to slide in the slide groove 431 inside the valve core 43, thereby causing the valve core 43 to move in the direction away from the center axis of the valve stem to squeeze the first sealing member 51, thereby closing the valve. When opening the valve, the valve core 43 is first separated from the first sealing member 51 and then moves in the direction away from the valve body 1. When closing the valve, the valve core 43 first contacts with the valve body 1 and then moves toward the first sealing member 51 to squeeze the first sealing member 51, thereby reducing the friction between the valve core 43 and the first sealing member 51, thereby reducing the wear between the valve core 43 and the first sealing member 51 when the valve body 1 is switched.

[0043] Embodiment 3 In actual use, it is found that when one of the valve cores 43 leaks due to wear of the first sealing member 51, it is impossible to alert the staff and emergency treatment cannot be performed on the seal, which can easily cause further leakage. Further improvements are made on the basis of the above embodiment.

[0044] When in use, when the valve is opened from a closed state, the handle is turned to move the upper valve stem 44 away from the valve body 1, so that the second piston plate 443 squeezes the gas inside the upper valve bonnet 2, so that the gas inside the upper valve bonnet 2 enters the energy storage tank 11 through the second exhaust hole 22 and the first air inlet hole 111. The upper valve stem 44 moves away from the valve body 1 and drives the lower valve stem 41 to move upward, so that the first piston plate 412 squeezes the gas inside the lower valve bonnet 3, so that the gas inside the lower valve bonnet 3 enters the limiting groove 12, so that the limiting column 121 When the valve is opened, the pressure inside the valve body 1 increases, so that the detection member 52 drives the third piston plate 54 to slide upward. When the valve is closed from the open state, the upper valve stem 44 drives the lower valve stem 41 to move toward the valve body 1, so that the first piston plate 412 moves in the opposite direction inside the lower valve cap 3, so that the gas inside the limiting groove 12 enters the lower valve cap 3, so that the limiting column 121 moves in the direction away from the detection groove 53. When a valve core 43 leaks, the medium enters the valve body 1, causing the internal pressure of the valve body 1 to increase continuously. Since the valve is in a closed state, the limiting column 121 does not limit the third piston plate 54. At this time, the medium in the pipeline inside the valve body 1 gradually increases, causing the detection member 52 to float upward. The upward floating of the detection member 52 drives the third piston plate 54 to move inside the detection groove 53, so that the gas inside the detection groove 53 enters the sealing groove 55, so that the second sealing member 551 moves inside the sealing groove 55, so that the second sealing member 551 no longer seals the first The exhaust hole 112 allows the internal gas of the energy storage tank 11 to enter the first sealing member 51, thereby increasing the internal pressure of the first sealing member 51, so that the first sealing member 51 further squeezes the valve core 43, thereby increasing the sealing performance of the valve body 1, and driving the warning column 541 to move upward while the third piston plate 54 moves upward, so that the warning column 541 extends out of the valve body 1. When one of the valve cores 43 of the valve leaks, the warning column 541 extends out of the valve body 1 to prompt the staff, and at the same time increases the sealing performance between the first sealing member 51 and the valve core 43 to prevent further leakage of the valve.

[0045] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A double valve, comprising a valve body (1), an upper valve cap (2) and a lower valve cap (3), characterized in that: Also includes: A valve core assembly (4), the valve core assembly (4) comprising a lower valve stem (41) arranged inside the lower valve cap (3), a slider (42) being arranged at one end of the lower valve stem (41), a valve core (43) being arranged at one end of the lower valve stem (41) close to the slider (42), a slide groove (431) being provided inside the valve core (43), and the slider (42) being able to slide inside the slide groove (431) to move the valve core (43) in the direction of the center line of the lower valve stem (41); A valve seat assembly (5), the valve seat assembly (5) comprising a first sealing member (51) arranged inside the valve body (1), the first sealing member (51) being capable of cooperating with the valve core (43) to seal the valve body (1), the valve seat assembly (5) further comprising a detection member (52) arranged inside the valve body (1), when the valve body (1) leaks, the detection member (52) is capable of floating due to the medium pressure, thereby increasing the internal pressure of the first sealing member (51) to squeeze the valve core (43).

2. The double valve according to claim 1, characterized in that: A wedge block (411) is fixedly connected to one end of the lower valve stem (41) close to the valve body (1), and the wedge block (411) is fixedly connected to the slider (42). There are at least two valve cores (43) which are symmetrically distributed along the central axis of the lower valve stem (41).

3. The double valve according to claim 2, characterized in that: One end of the lower valve stem (41) close to the wedge block (411) is fixedly connected to a first piston plate (412), and the first piston plate (412) is slidably connected to the inner wall of the lower valve bonnet (3). When the valve is opened, the first piston plate (412) can squeeze the internal gas of the lower valve bonnet (3), and the inner wall of the lower valve bonnet (3) is provided with a third exhaust hole (31).

4. The double valve according to claim 3, characterized in that: An energy storage tank (11) is provided inside the valve body (1), a first air inlet (111) is provided inside the energy storage tank (11), a one-way valve and a relief valve are provided at the first air inlet (111), and a first air exhaust hole (112) is provided inside the energy storage tank (11).

5. The double valve according to claim 4, characterized in that: The valve core assembly (4) further comprises an upper valve stem (44) arranged inside the upper valve bonnet (2); one end of the upper valve stem (44) is fixedly connected to a connecting column (441); a connecting groove (442) is provided inside the connecting column (441); one end of the lower valve stem (41) away from the wedge block (411) is fixedly connected to a connecting disk (413); the connecting disk (413) and the connecting groove (442) are slidably connected; the connecting column (441) and the inner wall of the upper valve bonnet (2) are slidably connected; and the end of the upper valve stem (44) away from the lower valve stem (41) passes through the upper valve bonnet (2) and is threadedly connected to the upper valve bonnet (2).

6. The double valve according to claim 5, characterized in that: A second piston plate (443) is fixedly connected to one end of the connecting column (441) away from the lower valve stem (41); the second piston plate (443) is slidably connected to the upper valve cap (2); a second air inlet hole (21) and a second air exhaust hole (22) are formed on the inner wall of the upper valve cap (2); the second air exhaust hole (22) is connected to the first air inlet hole (111) of the energy storage tank (11).

7. The double valve according to claim 6, characterized in that: The valve body (1) is provided with a detection groove (53) inside, a detection hole (531) is provided at the bottom of the detection groove (53), the detection member (52) is capable of sealing the detection hole (531), a third piston plate (54) is slidably connected inside the detection groove (53), an end of the third piston plate (54) away from the detection member (52) is fixedly connected to a warning column (541), a first elastic member (532) is provided in the detection groove (53), one end of the first elastic member (532) is fixedly connected to the inner wall of the detection groove (53), and the other end of the first elastic member (532) is fixedly connected to an end of the third piston plate (54) close to the warning column (541).

8. The double valve according to claim 7, characterized in that: A limiting groove (12) is provided inside the valve body (1), a limiting column (121) is slidably connected inside the limiting groove (12), the limiting groove (12) is connected to the third exhaust hole (31), the limiting groove (12) is connected to the detection groove (53), and the limiting column (121) can limit the third piston plate (54) by sliding.

9. The double valve according to claim 8, characterized in that: The valve body (1) is provided with a sealing groove (55) inside, a second sealing member (551) is slidably connected inside the sealing groove (55), the sealing groove (55) is connected to the detection groove (53) through a pipeline, a through hole is provided at one end of the second sealing member (551), and the second sealing member (551) can slide to connect the first exhaust hole (112) with the first sealing member (51) through the through hole.

10. The double valve according to claim 9, characterized in that: There are two lower valve caps (3) and they are fixedly connected to the two ends of the same side of the valve body (1). There are two upper valve caps (2), and one end of each upper valve cap (2) is fixedly connected to the end of the corresponding lower valve cap (3) away from the valve body (1).

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