A hard-sealed leak-proof needle valve

Abstract

The present invention relates to the technical field of valves, and particularly to a hard-sealed leak-proof needle valve, which includes a valve seat and a valve core. An installation cavity is provided in the valve seat, and a first sealing surface is provided on the inner wall of the installation cavity. The first sealing surface is conical. Liquid inlets and liquid outlets are provided on both sides of the valve seat, and the liquid inlets and liquid outlets communicate with the installation cavity. The valve core is slidably arranged in the installation cavity. In the present invention, a first sealing portion, a second sealing portion, an intermediate connecting portion and a valve seat are provided. Since the first cavity is between the liquid inlet and the liquid outlet, and the pressure in the first cavity is less than the fluid pressure at the liquid inlet and greater than the fluid pressure at the liquid outlet, the fluid at the liquid inlet is less likely to flow into the liquid outlet through the first cavity. In addition, the setting of the first cavity also reduces the pressure difference received by the sealing surface of the valve core, and correspondingly reduces the radial or axial stress inside the valve core. Therefore, the problem of plastic deformation of the valve core can be effectively improved, which is beneficial to improving the sealing effect of the needle valve.

Description

Technical Field

[0001] The present invention relates to the technical field of valves, and particularly to a hard-sealing leak-proof needle valve. Background Art

[0002] A needle valve is a fine-tuning valve used to precisely control the fluid flow rate. It is mainly applied to high-pressure fluid transportation. It is named needle valve because the head of its valve stem is needle-shaped. Its working principle is to drive the valve core to move up and down through a rotating operating mechanism, change the distance between the needle-shaped valve core and the valve seat, so as to change the passage area through which the fluid passes and achieve precise control of the flow rate.

[0003] The seal of the needle valve is achieved by the mutual fitting of the conical sealing surface of the valve seat and the conical sealing surface of the valve core. When the needle valve is in the sealed state, the pressure of the fluid on the inlet side of the needle valve against the sealing surface of the needle valve is much greater than the pressure of the fluid on the outlet side of the needle valve against the sealing surface of the needle valve. Due to the excessive pressure difference on both sides of the sealing surface of the needle valve, a large radial or axial stress will be generated inside the valve core, which is likely to cause plastic deformation of the valve core and greatly reduce the sealing effect of the needle valve. Summary of the Invention

[0004] Based on this, in view of the problems existing in the current needle valve, it is necessary to provide a hard-sealing leak-proof needle valve to solve the problem that the pressure difference on both sides of the valve core is too large and the valve core is prone to plastic deformation under the sealed state of the needle valve.

[0005] The above object is achieved by the following technical solutions:

[0006] A hard-sealing leak-proof needle valve includes:

[0007] A valve seat, an installation cavity is provided in the valve seat, a first sealing surface is provided on the inner wall of the installation cavity, and a liquid inlet and a liquid outlet are provided on both sides of the valve seat. The liquid inlet and the liquid outlet communicate with the installation cavity;

[0008] A valve core, the valve core is slidably arranged in the installation cavity, and the valve core can move along a first axis so that the valve core and the first sealing surface can be mutually attached or separated from each other;

[0009] The valve core includes a first sealing portion, a second sealing portion and an intermediate connecting portion. The first sealing portion and the second sealing portion are arranged at intervals along the first axis, and the intermediate connecting portion is connected between the first sealing portion and the second sealing portion;

[0010] When the valve core and the first sealing surface are mutually attached, the first sealing portion, the second sealing portion, the intermediate connecting portion and the circumferential direction of the first sealing surface enclose a closed first cavity, and the pressure in the first cavity is less than the fluid pressure at the liquid inlet and greater than the fluid pressure at the liquid outlet.

[0011] Preferably, the intermediate connecting portion is a rubber ring, and both ends of the rubber ring are fixedly connected to the first sealing portion and the second sealing portion respectively. Moreover, the rubber ring, the first sealing portion and the second sealing portion enclose a closed second cavity, and the preset pressure in the second cavity is less than the fluid pressure at the liquid inlet and greater than the fluid pressure at the liquid outlet.

[0012] Preferably, a support assembly is provided in the first sealing portion, and the support assembly has an extended state and a contracted state;

[0013] When in the extended state, the intermediate connecting portion is surrounded by the support assembly into its interior;

[0014] When in the contracted state, the intermediate connecting portion is exposed from the support assembly.

[0015] Preferably, the support assembly includes a sleeve and a power unit. The sleeve is slidably disposed in the first sealing portion, and the axis of the sleeve coincides with the first axis. The power unit is disposed inside the first sealing portion, and the power unit is used to drive the sleeve to move along the first axis;

[0016] When the support assembly is in the extended state, the intermediate connecting portion is surrounded by the sleeve into its interior;

[0017] When the support assembly is in the contracted state, the sleeve retracts into the first sealing portion, and the intermediate connecting portion is exposed from the sleeve.

[0018] Preferably, the power unit includes a first elastic member, a first liquid inlet hole, a first liquid outlet hole, a second liquid inlet hole and a second liquid outlet hole. The first elastic member is connected between the sleeve and the first sealing portion. The first liquid inlet hole is opened on one circumferential side of the sleeve, and the first liquid outlet hole is opened on the other circumferential side of the sleeve;

[0019] The second liquid inlet hole is opened on one side of the installation cavity, and the second liquid inlet hole is communicated with the liquid inlet;

[0020] The second liquid outlet hole is opened on the other side of the installation cavity, and the second liquid outlet hole is communicated with the liquid outlet;

[0021] When the first liquid inlet hole and the second liquid inlet hole are communicated, the fluid flows into the interior of the sleeve through the first liquid inlet hole and the second liquid inlet hole to drive the sleeve to move along the first axis in a direction away from the second sealing portion;

[0022] When the first liquid outlet hole and the second liquid outlet hole are communicated, the fluid flows out of the interior of the sleeve through the first liquid outlet hole and the second liquid outlet hole. Under the action of the first elastic member, the sleeve moves along the first axis in a direction close to the second sealing portion.

[0023] Preferably, a one-way valve is provided in the first liquid outlet hole, and the one-way valve restricts the fluid in the second liquid outlet hole from flowing into the first liquid outlet hole.

[0024] Preferably, a hard-sealed leak-proof needle valve further includes a driving assembly for driving the first sealing portion to move along the first axis.

[0025] Preferably, the driving assembly includes a valve stem, a second elastic member, and an intermediate cylinder. The valve stem is coaxially and fixedly connected to the upper end of the first sealing portion. The intermediate cylinder is threadedly connected to the valve seat. The axis of the intermediate cylinder coincides with the first axis. The intermediate cylinder and the valve stem are sleeved with each other, and the intermediate cylinder and the valve stem can move synchronously along the first axis and rotate relative to the first axis. The second elastic member is sleeved outside the valve stem, and both ends of the second elastic member are fixedly connected to the intermediate cylinder and the first sealing portion respectively.

[0026] Preferably, a hard-sealed leak-proof needle valve further includes a water inlet joint threadedly connected to the liquid inlet.

[0027] Preferably, a hard-sealed leak-proof needle valve further includes a water outlet joint threadedly connected to the liquid outlet.

[0028] The beneficial effects of the present invention are as follows:

[0029] The present invention is provided with a first sealing portion, a second sealing portion, an intermediate connecting portion, and a valve seat. The first sealing portion, the second sealing portion, the intermediate connecting portion, and the first sealing surface circumferentially enclose a closed first cavity. Since the first cavity is between the liquid inlet and the liquid outlet, and the pressure in the first cavity is less than the fluid pressure at the liquid inlet and greater than the fluid pressure at the liquid outlet, the fluid at the liquid inlet is less likely to flow into the liquid outlet through the first cavity, and the leak-proof effect is better. In addition, the setting of the first cavity also reduces the pressure difference received by the sealing surface of the valve core, and correspondingly reduces the radial or axial stress inside the valve core. Therefore, the problem of plastic deformation of the valve core can be effectively improved, which is beneficial to improving the sealing effect of the needle valve. Description of the Drawings

[0030] Figure 1 is the overall schematic diagram of the present invention;

[0031] Figure 2 is the front view of the present invention;

[0032] Figure 3 is the side view of the present invention;

[0033] Figure 4 is Figure 3 the A-A cross-sectional view in

[0034] Figure 5 is the schematic diagram of the valve closed state in the present invention;

[0035] Figure 6 is the schematic diagram of the state where the first sealing surface is blocked by foreign matters in the present invention;

[0036] Figure 7 Schematic diagram of the valve in the open state in the present invention;

[0037] Figure 8 Exploded view of the valve core in the present invention;

[0038] Figure 9 is Figure 4 Schematic diagram of the enlarged structure at position B in

[0039] Figure 10 is Figure 5 Schematic diagram of the enlarged structure at position C in

[0040] Figure 11 is Figure 6 Schematic diagram of the enlarged structure at position D in

[0041] Figure 12 is Figure 7 Schematic diagram of the enlarged structure at position E in

[0042] Wherein:

[0043] 100, valve seat; 110, installation cavity; 111, first sealing surface; 120, liquid inlet; 130, liquid outlet;

[0044] 200, valve core; 210, first sealing portion; 220, second sealing portion; 230, intermediate connecting portion;

[0045] 310, first cavity; 320, second cavity;

[0046] 400, support assembly; 410, sleeve; 420, power unit; 421, first elastic member; 422, first liquid inlet hole; 423, first liquid outlet hole; 424, second liquid inlet hole; 425, second liquid outlet hole; 430, check valve;

[0047] 500, valve stem; 510, second elastic member;

[0048] 600, intermediate cylinder; 610, screw; 620, handwheel; 630, third liquid inlet hole; 640, third liquid outlet hole;

[0049] 710, water inlet joint; 720, water outlet joint. Detailed implementation manners

[0050] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further details the present invention through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0051] The serial numbers assigned to components in this document itself, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meaning. The terms "connection" and "coupling" as used in this invention, unless otherwise specifically stated, both include direct and indirect connection (coupling). In the description of this invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention.

[0052] In this invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0053] Such as Figures 1 to 12As shown in the figure, a hard-sealed leak-proof needle valve includes a valve seat 100 and a valve core 200. An installation cavity 110 is formed in the valve seat 100. A first sealing surface 111 is formed on the inner wall of the installation cavity 110. The first sealing surface 111 is conical. Liquid inlets 120 and liquid outlets 130 are provided on both sides of the valve seat 100. The liquid inlets 120 and the liquid outlets 130 communicate with the installation cavity 110. The valve core 200 is slidably arranged in the installation cavity 110. The valve core 200 is needle-shaped and can move along a first axis so that the valve core 200 and the first sealing surface 111 can fit or separate from each other. Specifically, the first axis is the axis of the valve core 200. The valve core 200 includes a first sealing portion 210, a second sealing portion 220 and an intermediate connecting portion 230. The first sealing portion 210 and the second sealing portion 220 are arranged at intervals along the first axis. Both the first sealing portion 210 and the second sealing portion 220 are conical and are made of hard materials. The diameter of the small end of the first sealing portion 210 is larger than the diameter of the large end of the second sealing portion 220. The intermediate connecting portion 230 is connected between the first sealing portion 210 and the second sealing portion 220. When the valve core 200 and the first sealing surface 111 fit together, a closed first cavity 310 is circumferentially enclosed by the first sealing portion 210, the second sealing portion 220, the intermediate connecting portion 230 and the first sealing surface 111. The pressure in the first cavity 310 is less than the fluid pressure at the liquid inlet 120 and greater than the fluid pressure at the liquid outlet 130.

[0054] In the open valve state, the fluid enters the installation cavity 110 of the needle valve from the liquid inlet 120, then flows out from the inside of the installation cavity 110 to the liquid outlet 130, and finally flows out of the needle valve.

[0055] In the closed valve state, the directional flow of the fluid from the liquid inlet 120 to the liquid outlet 130 stops. At this time, the valve core 200 and the first sealing surface 111 fit together. Specifically, a closed first cavity 310 is circumferentially enclosed by the first sealing portion 210, the second sealing portion 220, the intermediate connecting portion 230 and the first sealing surface 111. Since the first cavity 310 is between the liquid inlet 120 and the liquid outlet 130, and the pressure in the first cavity 310 is less than the fluid pressure at the liquid inlet 120 and greater than the fluid pressure at the liquid outlet 130, it is more difficult for the fluid at the liquid inlet 120 to flow into the liquid outlet 130 through the first cavity 310, and the leak-proof effect is better. In addition, the setting of the first cavity 310 also reduces the pressure difference received by the sealing surface of the valve core 200, and correspondingly reduces the radial or axial stress inside the valve core 200. Therefore, the problem of plastic deformation of the valve core 200 can be effectively improved, which is beneficial to improving the sealing effect of the needle valve.

[0056] In this embodiment, as Figures 9 - 10As shown, the middle connection part 230 is a rubber ring. The two ends of the rubber ring are respectively fixedly connected to the first sealing part 210 and the second sealing part 220. The rubber ring, the first sealing part 210 and the second sealing part 220 enclose a sealed second cavity 320. The preset pressure in the second cavity 320 is less than the fluid pressure at the liquid inlet 120 and greater than the fluid pressure at the liquid outlet 130.

[0057] In the closed valve state, both the first sealing part 210 and the second sealing part 220 are in contact with the first sealing surface 111. At the same time, the first sealing part 210, the second sealing part 220, the middle connection part 230 and the installation cavity 110 circumferentially enclose a first cavity 310. At the same time, the first sealing part 210, the second sealing part 220 and the middle connection part 230 circumferentially enclose a closed second cavity 320. And the pressure value in the second cavity 320 is between the fluid pressure at the liquid inlet 120 and the fluid pressure at the installation cavity 110. At this time, if the pressure value in the first cavity 310 is less than the pressure value in the second cavity 320, the middle connection part 230 expands and arches outwards, so that the fluid pressure in the first cavity 310 increases to be greater than the fluid pressure at the liquid inlet 120 and less than the fluid pressure at the liquid outlet 130.

[0058] In this embodiment, as Figure 7 shown, a support assembly 400 is provided in the first sealing part 210. The support assembly 400 has an extended state and a contracted state. When the support assembly 400 is in the extended state, the middle connection part 230 is surrounded by the support assembly 400 into its interior. When the support assembly 400 is in the contracted state, the middle connection part 230 is exposed from the support assembly 400.

[0059] In the open valve state, the valve core 200 is not in contact with the first sealing surface 111. At this time, the support assembly 400 is in the extended state, and the middle connection part 230 is surrounded by the support assembly 400 into its interior. Therefore, the middle connection part 230 is protected by the support assembly 400 inside it and will not be damaged due to direct contact between the middle connection part 230 and the fluid.

[0060] In the closed valve state, the support assembly 400 is in the contracted state, and the middle connection part 230 is exposed from the inside of the support assembly 400. At this time, the middle connection part 230 expands outwards so that the fluid pressure value in the first cavity 310 increases to be between the fluid pressure at the liquid inlet 120 and the fluid pressure at the liquid outlet 130.

[0061] It can be understood that in the valve-closed state, if there are foreign objects or impurities remaining at the position corresponding to the first sealing surface 111 and the second sealing portion 220, the second sealing portion 220 will be unable to continue moving downward before reaching the preset position. Since the first sealing portion 210 and the second sealing portion 220 are flexibly connected by the intermediate connecting portion 230, the first sealing portion 210 will still move downward. Therefore, the distance between the first sealing portion 210 and the second sealing portion 220 will gradually decrease. At this time, the intermediate connecting portion 230 is compressed by the force, and the intermediate connecting portion 230 expands outward so that the outer peripheral surface of the intermediate connecting portion 230 fits with the first sealing surface 111, thereby forming a temporary sealing portion that can replace the second sealing portion 220. In this way, the connection of the first sealing surface 111 can still maintain two seals to prevent leakage at the sealing portion of the needle valve.

[0062] In this embodiment, as Figures 7 - 10 shown, the support assembly 400 includes a sleeve 410 and a power unit 420. The sleeve 410 is slidably disposed inside the first sealing portion 210, and the axis of the sleeve 410 coincides with the first axis. The power unit 420 is also disposed inside the first sealing portion 210, and the power unit 420 is used to drive the sleeve 410 to move along the first axis. When the support assembly 400 is in the extended state, the intermediate connecting portion 230 is surrounded by the sleeve 410 into its interior. When the support assembly 400 is in the contracted state, the sleeve 410 contracts into the first sealing portion 210, and the intermediate connecting portion 230 is exposed from the sleeve 410.

[0063] In the valve-open state, the power unit 420 drives the sleeve 410 to move along the first axis in a direction away from the second sealing portion 220. Then the sleeve 410 contracts into the first sealing portion 210. At this time, the intermediate connecting portion 230 is exposed from the sleeve 410 so that when the first sealing portion 210 and the second sealing portion 220 are in contact with the first sealing surface 111, the intermediate connecting portion 230 can expand outward to increase the pressure value in the first cavity 310 to be between the fluid pressure at the liquid inlet 120 and the fluid pressure at the liquid outlet 130.

[0064] In the valve-closed state, the power unit 420 drives the sleeve 410 to move along the first axis in a direction close to the second sealing portion 220. Then the sleeve 410 extends from the inside of the first sealing portion 210. At this time, the intermediate connecting portion 230 is surrounded by the sleeve 410 into its interior, thereby preventing the intermediate connecting portion 230 from coming into contact with the fluid and being damaged during the fluid transportation process.

[0065] In this embodiment, as Figures 9 - 12As shown, the power unit 420 includes a first elastic member 421, a first liquid inlet hole 422, a first liquid outlet hole 423, a second liquid inlet hole 424, and a second liquid outlet hole 425. The first elastic member 421 is connected between the sleeve 410 and the first sealing portion 210. Specifically, the first elastic member 421 is a compression spring. The first liquid inlet hole 422 is opened on one circumferential side of the sleeve 410, the first liquid outlet hole 423 is opened on the other circumferential side of the sleeve 410, the second liquid inlet hole 424 is opened on one side of the installation cavity 110, the second liquid inlet hole 424 is communicated with the liquid inlet 120, the second liquid outlet hole 425 is opened on the other side of the installation cavity 110, and the second liquid outlet hole 425 is communicated with the liquid outlet 130. When the first liquid inlet hole 422 and the second liquid inlet hole 424 are communicated, the fluid flows into the inside of the sleeve 410 through the first liquid inlet hole 422 and the second liquid inlet hole 424 to drive the sleeve 410 to move along the first axis in a direction away from the second sealing portion 220. When the first liquid outlet hole 423 and the second liquid outlet hole 425 are communicated, the fluid flows out of the inside of the sleeve 410 through the first liquid outlet hole 423 and the second liquid outlet hole 425. Under the action of the first elastic member 421, the sleeve 410 moves along the first axis in a direction close to the second sealing portion 220.

[0066] In the initial state (valve-open state), the first liquid inlet hole 422 and the second liquid inlet hole 424 are in a non-communicated state. At this time, the fluid will not enter the inside of the sleeve 410. Under the action of the first elastic member 421, the sleeve 410 exposes from the inside of the first sealing portion 210. At this time, the intermediate connecting portion 230 is surrounded by the sleeve 410 into its inside, and the intermediate connecting portion 230 will not directly contact the fluid. Therefore, it can prevent the intermediate connecting portion 230 from being damaged by contacting the fluid during the fluid transportation process.

[0067] When it is necessary to close the valve, the valve core 200 is moved downward along the first axis. When the valve core 200 moves to the position where the first liquid inlet hole 422 and the second liquid inlet hole 424 are communicated, the fluid enters the cavity between the sleeve 410 and the first sealing portion 210 through the first liquid inlet hole 422 and the second liquid inlet hole 424. At this time, the fluid pushes the sleeve 410 to move upward along the first axis, and the first elastic member 421 is gradually compressed. At this time, the sleeve 410 shrinks into the inside of the first sealing portion 210, and the intermediate connecting portion 230 exposes from the surrounding of the sleeve 410.

[0068] When the valve needs to be opened, the valve core 200 is moved upward along the first axis. When the valve core 200 moves to a position where the first liquid outlet hole 423 communicates with the second liquid outlet hole 425, the fluid inside the cavity between the sleeve 410 and the first sealing part 210 flows out through the first liquid outlet hole 423 and the second liquid outlet hole 425. At this time, the pressure of the fluid on the sleeve 410 gradually decreases, the compression amount of the first elastic part 421 gradually decreases, and the first elastic part 421 pushes the sleeve 410 to gradually expose from inside the first sealing part 210. At this time, the intermediate connecting part 230 is surrounded by the sleeve 410 into its interior.

[0069] It can be understood that when closing the valve, if there are foreign objects or impurities at the position of the liquid inlet 120 corresponding to the second sealing part 220, the second sealing part 220 will stop moving downward before moving to the preset position, while the first sealing part 210 is still moving downward. Therefore, the distance between the first sealing part 210 and the second sealing part 220 will gradually decrease. Then the intermediate connecting part 230 is compressed by force, and the intermediate connecting part 230 expands outward so that the outer peripheral surface of the intermediate connecting part 230 fits with the liquid inlet 120, thereby forming a temporary seal that can replace the second sealing part 220. Therefore, two seals can still be maintained at the connection of the liquid inlet 120 to prevent leakage at the valve seal.

[0070] In this embodiment, as Figures 9 - 12 shown, a check valve 430 is provided in the first liquid outlet hole 423, and the check valve 430 restricts the fluid in the second liquid outlet hole 425 from flowing into the first liquid outlet hole 423.

[0071] The check valve 430 is set to restrict the fluid in the second liquid outlet hole 425 from flowing back into the first liquid outlet hole 423 in the valve closed state, thereby restricting the fluid from flowing back into the area between the sleeve 410 and the first sealing part 210 through the first liquid outlet hole 423, so as to restrict the upward movement of the sleeve 410 in the valve open state.

[0072] In this embodiment, as Figure 9 shown, a hard-sealing leak-proof needle valve further includes a driving assembly, and the driving assembly is used to drive the first sealing part 210 to move along the first axis.

[0073] When the valve core 200 needs to move along the first axis, the driving assembly is started, and the driving assembly drives the valve core 200 to move along the first axis so that the valve can be opened or closed.

[0074] In this embodiment, as Figures 9 - 12As shown, the driving component includes a valve stem 500, a second elastic member 510, an intermediate cylinder 600, and a screw rod 610. The valve stem 500 is coaxially and fixedly connected to the upper end of the first sealing portion 210. The screw rod 610 is threadedly connected to the valve seat 100. The screw rod 610 and the intermediate cylinder 600 are sleeved with each other, and the screw rod 610 and the intermediate cylinder 600 can move synchronously along the first axis and rotate relative to each other. The axis of the intermediate cylinder 600 coincides with the first axis. The lower part of the intermediate cylinder 600 is sleeved with the valve stem 500, and the intermediate cylinder 600 and the valve stem 500 can move synchronously along the first axis and rotate relative to the first axis. The second elastic member 510 is a compression spring. The second elastic member 510 is sleeved outside the valve stem 500, and both ends of the second elastic member 510 are fixedly connected to the intermediate cylinder 600 and the first sealing portion 210 respectively.

[0075] When closing the valve, the operator rotates the screw rod 610. The screw rod 610 drives the intermediate cylinder 600 to move downward along the first axis through threaded cooperation. The intermediate cylinder 600 pushes the first sealing portion 210 to move downward through the second elastic member 510. The first sealing portion 210 drives the second sealing portion 220 to move downward through the intermediate connecting portion 230. When the first sealing portion 210 is in contact with the first sealing surface 111, as the intermediate cylinder 600 continues to move downward, the second elastic member 510 is gradually compressed. At this time, the valve core 200 is closely attached to the first sealing surface 111. In this way, it is easy to control the sealing force between the first sealing surface 111 and the valve core 200, without worrying about the sealing force between the valve core 200 and the first sealing surface 111 being too large or the valve core 200 and the first sealing surface 111 not being able to fit tightly for sealing.

[0076] It can be understood that if there are foreign matters remaining on the first sealing surface 111, when the valve core 200 is closed, the second sealing portion 220 cannot fit tightly with the first sealing surface 111. At this time, the fluid will pass through the gap between the second sealing portion 220 and the first sealing surface 111 at a very high flow rate and scour the foreign matters remaining on the first sealing surface 111. As the amount of foreign matters remaining on the first sealing surface 111 gradually decreases, under the elastic action of the second elastic member 510, the first sealing portion 210 will gradually move downward so that after the foreign matters are scoured and removed, the first sealing portion 210 can drive the second sealing portion 220 to gradually move downward through the intermediate connecting portion 230, so that the second sealing portion 220 fits with the first sealing surface 111 again.

[0077] It should also be supplemented that a third liquid inlet hole 630 is provided on one side of the lower part of the middle cylinder 600, and a third liquid outlet hole 640 is provided on the other side of the lower part of the middle cylinder 600. In the open valve state, the first liquid inlet hole 422 and the third liquid inlet hole 630 are vertically offset. Similarly, the first liquid outlet hole 423 and the third liquid outlet hole 640 are vertically offset. At the same time, the second liquid inlet hole 424 and the third liquid inlet hole 630 are mutually offset, and the third liquid outlet hole 640 and the second liquid outlet hole 425 are mutually offset. Therefore, the fluid will not enter the space area between the first sealing part 210 and the sleeve 410. When the middle cylinder 600 drives the first sealing part 210 to move downward through the second elastic member 510 until both the first sealing part 210 and the second sealing part 220 are in contact with the first sealing surface 111, the second liquid inlet hole 424, the third liquid inlet hole 630 and the first liquid inlet hole 422 are communicated. At this time, the fluid can enter the space area between the first sealing part 210 and the sleeve 410, and push the sleeve 410 upward.

[0078] When the valve switches from the closed valve state to the open valve state, the middle cylinder 600 drives the first sealing part 210 to move upward through the first elastic member 421. When the first liquid outlet hole 423, the second liquid outlet hole 425 and the third liquid outlet hole 640 are communicated, the fluid in the space between the first sealing part 210 and the sleeve 410 is discharged outward through the first liquid outlet hole 423, the second liquid outlet hole 425 and the third liquid outlet hole 640. At this time, under the elastic force of the first elastic member 421, the sleeve 410 moves downward along the first axis until the sleeve 410 exposes from the lower part of the first sealing part 210.

[0079] It should also be supplemented that in order to rotate the screw rod 610, a hand wheel 620 is fixedly connected to the upper end of the screw rod 610, so as to facilitate the staff to rotate the screw rod 610 through the hand wheel 620.

[0080] In this embodiment, as Figure 4 shown, a hard-sealed leak-proof needle valve further includes a water inlet joint 710, and the water inlet joint 710 is threadedly connected in the liquid inlet 120. The water inlet joint 710 is provided to facilitate the connection of the water inlet pipe.

[0081] In this embodiment, as Figure 4 shown, a hard-sealed leak-proof needle valve further includes a water outlet joint 720, and the water outlet joint 720 is threadedly connected in the liquid outlet 130. The water outlet joint 720 is provided to facilitate the connection of the water outlet pipe.

[0082] In this embodiment, in order to improve the corrosion resistance of the needle valve, specifically, an anti-corrosion material, such as nickel-chromium alloy, is plated on the cavity wall of the installation cavity 110 to improve the corrosion resistance of the needle valve.

[0083] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0084] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the appended claims.

Claims

1. A hard-sealed leak-proof needle valve, characterized in that: include: A valve seat, wherein a mounting cavity is formed in the valve seat, a first sealing surface is formed on the inner wall of the mounting cavity, and a liquid inlet and a liquid outlet are formed on both sides of the valve seat, wherein the liquid inlet and the liquid outlet are connected to the mounting cavity; A valve core is slidably disposed in the installation cavity, and the valve core can move along the first axis so that the valve core and the first sealing surface can fit together or move away from each other; The valve core comprises a first sealing portion, a second sealing portion and an intermediate connecting portion, the first sealing portion and the second sealing portion are both conical and spaced apart along the first axis, the small end diameter of the first sealing portion is larger than the large end diameter of the second sealing portion, and the intermediate connecting portion is connected between the first sealing portion and the second sealing portion; when the valve core and the first sealing surface are attached to each other, the first sealing portion, the second sealing portion, the intermediate connecting portion and the first sealing surface circumferentially enclose a closed first cavity, and the pressure in the first cavity is smaller than the fluid pressure at the liquid inlet and larger than the fluid pressure at the liquid outlet; The middle connecting part is a rubber ring, and the two ends of the rubber ring are fixedly connected to the first sealing part and the second sealing part respectively, and the rubber ring, the first sealing part and the second sealing part enclose a closed second cavity, and the preset pressure in the second cavity is less than the fluid pressure at the liquid inlet and greater than the fluid pressure at the liquid outlet; a support assembly is provided in the first sealing part, and the support assembly includes a sleeve and a power unit. The sleeve is slidably arranged in the first sealing part, and the axis of the sleeve coincides with the first axis. The power unit is arranged inside the first sealing part, and the power unit is used to drive the sleeve to move along the first axis; the support assembly has an extended state and a retracted state. In the valve opening state, the valve core does not contact the first sealing surface. At this time, the support assembly is in an extended state, and the middle connecting part is surrounded by the sleeve to its interior; in the valve closing state, when the support assembly is in a retracted state, the sleeve is retracted to the interior of the first sealing part, and the middle connecting part is exposed from the sleeve.

2. A hard-sealed leak-proof needle valve according to claim 1, characterized in that: The power unit comprises a first elastic member, a first liquid inlet hole, a first liquid outlet hole, a second liquid inlet hole and a second liquid outlet hole, the first elastic member is connected between the sleeve and the first sealing portion, the first liquid inlet hole is provided on one circumferential side of the sleeve, and the first liquid outlet hole is provided on the other circumferential side of the sleeve; The second liquid inlet hole is opened on one side of the installation cavity, and the second liquid inlet hole is connected with the liquid inlet port; The second liquid outlet hole is opened on the other side of the installation cavity, and the second liquid outlet hole is connected with the liquid outlet port; When the first liquid inlet hole and the second liquid inlet hole are connected, the fluid flows into the sleeve through the first liquid inlet hole and the second liquid inlet hole to drive the sleeve to move along the first axis in a direction away from the second sealing portion; When the first liquid outlet hole and the second liquid outlet hole are connected, the fluid flows out from the inside of the sleeve through the first liquid outlet hole and the second liquid outlet hole, and under the action of the first elastic member, the sleeve moves along the first axis toward the second sealing portion.

3. A hard-sealed leak-proof needle valve according to claim 2, characterized in that: A one-way valve is arranged in the first liquid outlet hole, and the one-way valve restricts the fluid in the second liquid outlet hole from flowing into the first liquid outlet hole.

4. A hard-sealed leak-proof needle valve according to claim 1, characterized in that: Also included is a driving assembly for driving the first sealing portion to move along the first axis.

5. A hard-sealed leak-proof needle valve according to claim 4, characterized in that: The driving assembly includes a valve stem, a second elastic member and an intermediate cylinder. The valve stem is coaxially fixedly connected to the upper end of the first sealing portion. The intermediate cylinder is threadedly connected to the valve seat. The axis of the intermediate cylinder coincides with the first axis. The intermediate cylinder and the valve stem are sleeved with each other, and the intermediate cylinder and the valve stem can move synchronously along the first axis and rotate relative to each other around the first axis. The second elastic member is sleeved on the outside of the valve stem and the two ends of the second elastic member are respectively fixedly connected to the intermediate cylinder and the first sealing portion.

6. A hard-sealed leak-proof needle valve according to claim 1, characterized in that: It also includes a water inlet joint, which is threadedly connected in the liquid inlet.

7. A hard-sealed leak-proof needle valve according to claim 1, characterized in that: It also includes a water outlet joint, which is threadedly connected in the liquid outlet.

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