Stop valve

Abstract

The stop valve comprises a valve body and a valve cover, the valve cover is fixed to the upper end of the valve body, a valve rod is slidably connected to the valve cover, a valve clack is arranged in the valve body, the lower end of the valve rod is connected with the upper end of the valve clack, the lower end of the valve rod is sleeved with a corrugated pipe, and the lower end of the corrugated pipe is fixedly welded to the lower end of the valve rod. A sealing end part is integrally arranged at the upper end of the corrugated pipe, an axial sealing piece is arranged on the side surface of the sealing end part, a limiting convex edge is integrally arranged at the upper end of the side surface of the sealing end part, and the limiting convex edge is clamped between the upper end surface of the valve body and the lower end surface of the valve cover; a purging through hole is formed in the bottom of the valve body, the axial center line of the purging through hole coincides with the axial center line of the valve clack, and a flange connector is fixedly arranged at the position, located at an outer port of the purging through hole, of the valve body. According to the technical scheme, structural design is reasonable, sealing performance is good, the sealing face of the lower end of the valve clack is convenient to clean, service life is long, and practicability is good.

Description

Technical Field

[0001] This invention relates to the field of valve technology, and more specifically to a gate valve. Background Technology

[0002] A gate valve opens and closes by raising and lowering the valve stem. When the valve stem moves upward, the valve disc leaves the valve seat, allowing fluid to pass through; when the valve stem moves downward, the valve disc presses against the valve seat to form a seal, stopping the fluid flow. However, existing gate valve structures have shortcomings: the valve body and valve cover are generally sealed only by a sealing ring. When fluid passes through the valve body, it may flow towards the sealing ring under the axial force of the fluid medium. If the gate valve transports highly toxic or corrosive fluids, these fluids may corrode the seals, making it difficult for the sealing ring to effectively seal the fluid, leading to leakage, affecting external safety, and shortening service life. Furthermore, at the moment the valve closes, the medium velocity changes, easily generating eddies. These eddies may guide impurities to the vicinity of the sealing surface, causing them to adhere to the lower end of the valve disc's sealing surface. Cleaning these adhered impurities is cumbersome. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a gate valve with reasonable structural design, good sealing performance, easy cleaning of the sealing surface at the lower end of the valve disc, long service life and good practicality.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a stop valve, comprising a valve body and a valve cover, wherein the valve cover is fixed to the upper end of the valve body, a valve stem is slidably connected to the valve cover, a valve disc is provided in the valve body, the lower end of the valve stem is connected to the upper end of the valve disc, a bellows is sleeved on the lower end of the valve stem, the lower end of the bellows is welded and fixed to the lower end of the valve stem, a sealing end is integrally provided on the upper end of the bellows, an axial sealing element is provided on the side of the sealing end, and a limiting protrusion is integrally provided on the upper side of the sealing end;

[0005] The valve body has a vertical through hole at the upper end, and a positioning notch is provided at the upper port of the vertical through hole. The limiting protrusion is provided in the positioning notch, and a fireproof seal is provided between the side of the limiting protrusion and the inner wall of the positioning notch.

[0006] The sealing end is sealed by an axial sealing element and the inner wall of the vertical through hole, and the upper end of the valve body is sealed by a fireproof sealing element and the lower end of the valve cover.

[0007] The bottom of the valve body is provided with a purge through hole, the axial center line of which coincides with the axial center line of the valve disc. A flange joint is fixedly provided on the valve body at the outer port of the purge through hole, and a sealing cover or cleaning and purging device is provided on the flange joint.

[0008] The present invention is further configured such that: the lower end of the valve disc has a conical structure, and the lower end of the valve disc is integrally provided with a hard sealing surface, and the upper end of the valve disc is provided with a valve stem connecting groove, the upper end of the inner wall surface of the valve stem connecting groove is provided with an internal thread, the lower end of the valve stem is provided with an annular groove, the annular groove is provided with a split ring, and a valve disc cap is provided above the split ring on the valve stem, and the valve disc is connected to the valve stem by the split ring and the valve disc cap.

[0009] The present invention is further configured such that: a vertical through hole is provided at the upper end of the valve body, a positioning notch is provided at the upper port of the vertical through hole, the limiting protrusion is provided in the positioning notch, and a fireproof seal is provided between the outer surface of the limiting protrusion and the inner wall surface of the positioning notch.

[0010] The present invention is further configured such that: a sealing protrusion is integrally provided on the lower end face of the valve cover, aligned with the positioning notch position; the valve cover and the valve body are locked together by bolts; when the valve cover and the valve body are locked together, the sealing protrusion simultaneously presses against the upper end face of the limiting protrusion and the fireproof seal.

[0011] The present invention is further configured such that: a support frame is integrally provided on the upper end of the valve cover, a valve stem nut is fixedly provided on the support frame, the upper end of the valve stem is exposed at the upper port of the inner hole of the valve stem nut, an operating handwheel is provided on the valve stem nut, the operating handwheel and the valve stem nut transmit torque through a hexagonal connection, a trapezoidal thread is provided between the valve stem nut and the valve stem, rotating the operating handwheel drives the valve stem nut to rotate, and the valve stem is driven to rise and fall by the trapezoidal thread on the valve stem nut.

[0012] The present invention is further configured such that: a limiting block assembly for restricting the degree of freedom of rotation of the valve stem around its axis is provided at the upper end of the valve stem; the limiting block assembly includes a first limiting block, a second limiting block, and screws; a first limiting plane and a second limiting plane are provided on the valve stem; the first limiting block is installed at the first limiting plane, and the second limiting block is installed at the second limiting plane; a vertical limiting rib is integrally provided on the support frame; the first limiting block and the second limiting block are locked together by screws; when the first limiting block and the second limiting block are locked together, a limiting groove is formed near the side of the first limiting block and the second limiting block; and the vertical limiting rib is inserted into the aligned limiting groove.

[0013] The present invention is further configured such that: the lower end of the valve disc is provided with an external threaded connection part, and the lower end of the valve disc is fitted with a non-metallic seal and a valve disc nut, and the non-metallic seal is locked by the valve disc nut.

[0014] The beneficial effects of this invention are as follows: Compared with the prior art, this invention has a reasonable structural design. The lower end of the bellows is welded and fixed to the lower end of the valve stem, and a sealing end is integrally provided on the upper end of the bellows. An axial sealing element is provided on the side of the sealing end, and a limiting protrusion is integrally provided on the upper side of the sealing end. This limiting protrusion is sandwiched between the upper end face of the valve body and the lower end face of the valve cover. The valve body and the valve cover are connected by bolts. When the valve body and the valve cover are locked, a seal is formed by the fireproof sealing element and the axial sealing element. The sealing effect of the axial sealing element is not affected by axial force, thus avoiding the influence of axial medium force and axial sealing force on the seal between the valve body and the valve cover. A purge through hole is provided at the bottom of the valve body. The axial center line of the purge through hole coincides with the axial center line of the valve disc, allowing purging to be performed during valve opening and closing. The lower end of the valve disc is conical and coaxial with the purge through hole. After the purge gas is blown toward the valve disc, it is evenly distributed to the sealing surface at the bottom of the valve disc, which can keep the sealing surface clean. The sealing surface at the lower end of the valve disc is easy to clean, has good sealing performance, long service life and good practicality.

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0017] Figure 2 This is a partial structural diagram of Embodiment 1 of the present invention. Figure 1 ;

[0018] Figure 3 This is a partial structural diagram of Embodiment 1 of the present invention. Figure 2 ;

[0019] Figure 4 This is a cross-sectional schematic diagram of Embodiment 1 of the present invention;

[0020] Figure 5 for Figure 4 Enlarged schematic diagram of section I;

[0021] Figure 6 This is a schematic diagram of the valve disc in the open state according to Embodiment 1 of the present invention;

[0022] Figure 7 This is an assembly diagram of the limiting block assembly according to Embodiment 1 of the present invention;

[0023] Figure 8 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0024] Figure 9 This is a schematic diagram of the assembly of the valve disc and valve stem in Embodiment 2 of the present invention. Detailed Implementation

[0025] In the description of this embodiment, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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 orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] Example 1

[0027] See Figures 1 to 7 The present invention discloses a shut-off valve, comprising a valve body 1 and a valve cover 2. The valve cover 2 is fixed to the upper end of the valve body 1. A valve stem 3 is slidably connected to the valve cover 2. A valve disc 4 is provided inside the valve body 1. The lower end of the valve stem 3 is connected to the upper end of the valve disc 4. A bellows 5 is sleeved on the lower end of the valve stem 3. The lower end of the bellows 5 is welded and fixed to the lower end of the valve stem 3. A sealing end 51 is integrally provided on the upper end of the bellows 5. An axial sealing element 6 is provided on the side of the sealing end 51. A limiting protrusion 511 is integrally provided on the upper side of the sealing end 51.

[0028] The valve body 1 has a vertical through hole 13 at its upper end. The valve body 1 has a positioning notch at the upper port of the vertical through hole 13. The limiting protrusion 511 is located in the positioning notch, and a fireproof seal 10 is provided between the outer surface of the limiting protrusion 511 and the inner wall of the positioning notch.

[0029] The sealing end 51 forms a seal between the axial sealing element 6 and the inner wall surface of the vertical through hole 13, and the upper end of the valve body 1 forms a seal between the fireproof sealing element 10 and the lower end of the valve cover 2.

[0030] The bottom of the valve body 1 is provided with a purge hole 11, the axial center line of the purge hole 11 coincides with the axial center line of the valve disc 4, and a flange joint 7 is fixedly provided on the valve body 1 at the outer port of the purge hole 11, and a sealing cover or cleaning and purging device is provided on the flange joint 7.

[0031] Preferably, the corrugated pipe 5 is made of austenitic stainless steel, such as 304 stainless steel or 316 stainless steel; the corrugated pipe 5 can also be made of nickel-based alloy: INCONEL X625; or copper and copper alloys; non-metallic materials such as PP and PE can also be used under special low pressure conditions.

[0032] The axial seal 6 is an O-ring or a lip ring. The material of the O-ring can be changed according to the application scenario, such as fluororubber, nitrile rubber, etc., and the lip ring can be a metal spring with tetrafluoroethylene or polyetheretherketone, etc.

[0033] The limiting protrusion 511 can prevent the sealing end 51 from moving under pressure.

[0034] The fireproof seal 10 is a high-temperature resistant seal, such as a metal spiral wound gasket, a metal toothed gasket, a metal octagonal ring, or a metal C-ring.

[0035] The upper end of the flange joint 7 is fixed to the bottom of the valve body 1 by welding, integrally set with the bottom of the valve body 1, or fixed by threaded connection.

[0036] To make the structural design of the present invention more reasonable, as a preferred embodiment, the lower end of the valve disc 4 is tapered, and the lower end of the valve disc 4 is integrally provided with a hard sealing surface 41, and the upper end of the valve disc 4 is provided with a valve stem connecting groove 42. The upper end of the inner wall surface of the valve stem connecting groove 42 is provided with an internal thread. The lower end of the valve stem 3 is provided with an annular groove, and a split ring 8 is provided in the annular groove. A valve disc cap 9 is provided above the split ring 8 on the valve stem 3. The valve disc 4 is connected to the valve stem 3 by the split ring 8 and the valve disc cap 9.

[0037] Preferably, a hard alloy layer 12 is welded to the sealing mating position between the valve body 1 and the valve disc 4; the hard sealing surface 41 at the lower end of the valve disc 4 is also made of hard alloy material.

[0038] The lower end face of the valve cover 2 is integrally provided with a sealing protrusion 21 aligned with the positioning notch. The valve cover 2 and the valve body 1 are locked together by bolts. When the valve cover 2 and the valve body 1 are locked together, the sealing protrusion 21 simultaneously presses against the limiting protrusion 511 and the upper end face of the fireproof seal 10.

[0039] A support frame 22 is integrally provided on the upper end of the valve cover 2. A valve stem nut 23 is fixedly provided on the support frame 22. The upper end of the valve stem 3 is exposed at the upper port of the inner hole of the valve stem nut 23. An operating handwheel 15 is provided on the valve stem nut 23. The operating handwheel 15 and the valve stem nut 23 transmit torque through a hexagonal connection. A trapezoidal thread is provided between the valve stem nut 23 and the valve stem 3. Rotating the operating handwheel 15 drives the valve stem nut 23 to rotate, and the valve stem 3 is driven to rise and fall by the trapezoidal thread on the valve stem nut 23.

[0040] The upper end of the valve stem 3 is provided with a limiting block assembly 14 for restricting the degree of freedom of rotation of the valve stem around the axis. The limiting block assembly 14 includes a first limiting block 141, a second limiting block 142 and a screw 143. The valve stem 3 is provided with a first limiting plane 31 and a second limiting plane 32. The first limiting block 141 is installed at the first limiting plane and the second limiting block 142 is installed at the second limiting plane. The support frame 22 is integrally provided with a vertical limiting rib 221. The first limiting block 141 and the second limiting block 142 are locked by screws. When the first limiting block 141 and the second limiting block 142 are locked, a limiting groove 144 is formed near the side of the first limiting block 141 and the second limiting block 142. The vertical limiting rib 221 is inserted into the aligned limiting groove 144. Preferably, the first limiting block 141 and the second limiting block 142 have the same shape, one of which is provided with a threaded hole and the other is provided with a through hole. The through hole is aligned with the threaded hole. When the first limiting block 141 and the second limiting block 142 are locked with screws, they clamp the limiting plane of the valve stem. The first limiting block 141 and the second limiting block 142 restrict the rotation of the valve stem, but do not affect its up and down movement.

[0041] Preferably, the valve cover 2 is provided with a valve stem through hole, and a packing groove is provided at the upper end of the valve stem through hole. A packing layer 16 is provided in the packing groove, and a packing pressure ring 17 is provided at the upper end of the packing layer. A packing pressure plate 18 is provided at the upper end of the packing pressure ring. The packing pressure plate 18 is fixed to the upper end of the valve body 1 by bolts. The contact surface between the packing pressure ring 17 and the packing pressure plate 18 is spherical. To avoid wear of the packing layer caused by misalignment when retightening the packing layer 16, the packing pressure plate 18 is provided with two screws. The screws are tightened one at a time. When tightening one screw, the other screw does not move, and the packing pressure plate 18 will be uneven. If the packing pressure plate 18 and the packing pressure ring 17 are integrated, the bottom edge of the tilted packing pressure ring 17 will scratch the surface of the packing groove. When the packing pressure plate 18 and the packing pressure ring 17 are separate, the tilt of the packing pressure plate 18 will not affect the vertical state of the packing pressure ring 17.

[0042] In practical applications, the lower end of the bellows 5 is welded and fixed to the lower end of the valve stem 3. A sealing end 51 is integrally provided on the upper end of the bellows 5. An axial seal 6 is provided on the side of the sealing end 51. A limiting protrusion 511 is integrally provided on the upper side of the sealing end 51. This limiting protrusion 511 is sandwiched between the upper end face of the valve body 1 and the lower end face of the valve cover 2. The valve body 1 and the valve cover 2 are connected by bolts. When the valve body 1 and the valve cover 4 are locked, a seal is formed by the fireproof seal 10 and the axial seal 6. The sealing effect of the axial seal 6 is not affected by axial force, avoiding the influence of axial medium force and axial sealing force on the seal between the valve body 1 and the valve cover 2. A purge hole 11 is provided at the bottom of the valve body 1. The axial center line of the purge hole 11 coincides with the axial center line of the valve disc 4, allowing for purging during valve opening and closing. The lower end of the valve disc 4 is conical and coaxial with the purge through hole 11. After the purge gas is blown toward the valve disc 4, it is evenly spread to the sealing surface at the bottom of the valve disc, which can keep the sealing surface clean.

[0043] A deep groove ball bearing is placed on both the upper and lower sides of the valve stem nut 23, and then they are placed together into the groove of the bracket. A nut is screwed on top to hold the deep groove ball bearing in place, and finally locked with a set screw. Installation is complete. During rotation operation, the valve stem does not rotate but only moves up and down. When the valve disc is open, the bellows is in the retracted state.

[0044] The operating handwheel 15 and valve stem nut 23 transmit torque through a hexagonal connection. The valve stem nut 23 and valve stem 3 are connected by a trapezoidal thread. Rotating the operating handwheel 15 causes the valve stem nut 23 to rotate. The valve stem 3 cannot rotate due to the influence of the limiting block 14, so it is driven to rise and fall by the trapezoidal thread on the valve stem nut 23.

[0045] The above technical solution has a reasonable structural design, good sealing performance, easy cleaning of the sealing surface at the lower end of the valve disc, long service life, and good practicality.

[0046] Example 2

[0047] See Figure 8 and Figure 9 This second embodiment is an improvement based on the technical solution of the first embodiment. The difference between this second embodiment and the first embodiment is that: the lower end of the valve disc 4 is provided with an external threaded connection, and the lower end of the valve disc 4 is fitted with a non-metallic sealing element 19 and a valve disc nut 20, which locks the non-metallic sealing element 19. The non-metallic sealing element 19 is made of materials such as tetrafluoroethylene, nylon, or polyetheretherketone.

[0048] After adding a non-metallic sealing element 19 to the valve disc 4, the seal between the valve body 1 and the disc 5 can adopt a soft and hard composite seal; thus, the gate valve has a soft and hard composite seal, which has a good sealing effect and reliable service life.

[0049] Furthermore, the structure is further improved based on the technical solution of this embodiment:

[0050] (1) The operating handwheel can be a bevel gear or an automatic operation such as pneumatic or electric. When the valve is pneumatically operated, the shut-off valve does not need to be equipped with a limit block.

[0051] (2) The valve disc adopts a double valve disc structure. A small valve disc is installed in the middle of the valve disc as a pilot to reduce the medium pressure difference before opening the valve disc, thereby reducing the thrust or torque required for valve operation.

[0052] The above embodiments, which describe the specific features of the present invention, are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above description of the invention shall fall within the scope of protection of the present invention.

Claims

1. A shut-off valve, comprising a valve body (1) and a valve cover (2), wherein the valve cover (2) is fixed to the upper end of the valve body (1), a valve stem (3) is slidably connected to the valve cover (2), a valve disc (4) is disposed inside the valve body (1), and the lower end of the valve stem (3) is connected to the upper end of the valve disc (4), characterized in that: The lower end of the valve stem (3) is fitted with a bellows (5), the lower end of the bellows (5) is welded and fixed to the lower end of the valve stem (1), and the upper end of the bellows (5) is integrally provided with a sealing end (51). An axial sealing element (6) is provided on the side of the sealing end (51), and a limiting protrusion (511) is integrally provided on the upper side of the sealing end (51). The valve body (1) is provided with a vertical through hole (13) at the upper end. The valve body (1) is provided with a positioning notch at the upper port of the vertical through hole (13). The limiting protrusion (511) is provided in the positioning notch, and a fireproof seal (10) is provided between the side of the limiting protrusion (511) and the inner wall of the positioning notch. The sealing end (51) is sealed between the axial sealing element (6) and the inner wall of the vertical through hole (13), and the upper end of the valve body (1) is sealed between the fireproof sealing element (10) and the lower end of the valve cover (2). The bottom of the valve body (1) is provided with a purge hole (11), the axial center line of the purge hole (11) coincides with the axial center line of the valve disc (4), and a flange joint (7) is fixedly provided at the outer port of the purge hole (11) of the valve body (1), and a sealing cover or cleaning and purging device is provided on the flange joint (7).

2. A shut-off valve according to claim 1, characterized in that: The lower end of the valve disc (4) has a conical structure, and the lower end of the valve disc (4) is integrally provided with a hard sealing surface (41). The upper end of the valve disc (4) is provided with a valve stem connecting groove (42). The upper end of the inner wall surface of the valve stem connecting groove (42) is provided with an internal thread. The lower end of the valve stem (3) is provided with an annular groove. The annular groove is provided with a split ring (8). The valve stem (3) is provided with a valve disc cap (9) above the split ring (8). The valve disc (4) is connected to the valve stem (3) by the split ring (8) and the valve disc cap (9).

3. A shut-off valve according to claim 2, characterized in that: The lower end face of the valve cover (2) is integrally provided with a sealing protrusion (21) aligned with the positioning notch. The valve cover (2) and the valve body (1) are locked together by bolts. When the valve cover (2) and the valve body (1) are locked together, the sealing protrusion (21) simultaneously presses against the upper end face of the limiting protrusion (511) and the fireproof seal (10).

4. A shut-off valve according to claim 3, characterized in that: The upper end of the valve cover (2) is integrally provided with a support frame (22), and a valve stem nut (23) is fixedly provided on the support frame (22). The upper end of the valve stem (3) is provided with the upper port of the inner hole of the valve stem nut (23). An operating handwheel (15) is provided on the valve stem nut (23). The operating handwheel (15) and the valve stem nut (23) transmit torque through a hexagonal connection. A trapezoidal thread is provided between the valve stem nut (23) and the valve stem (3). Rotating the operating handwheel (15) drives the valve stem nut (23) to rotate, and the valve stem (3) is driven to rise and fall by the trapezoidal thread on the valve stem nut (23).

5. A shut-off valve according to claim 4, characterized in that: The upper end of the valve stem (3) is provided with a limiting block assembly (14) for restricting the degree of freedom of rotation of the valve stem around the axis. The limiting block assembly (14) includes a first limiting block (141), a second limiting block (142) and a screw (143). The valve stem (3) is provided with a first limiting plane (31) and a second limiting plane (32). The first limiting block (141) is installed at the first limiting plane, and the second limiting block (142) is installed at the second limiting plane. The support frame (22) is integrally provided with a vertical limiting rib plate (221). The first limiting block (141) and the second limiting block (142) are locked by screws. When the first limiting block (141) and the second limiting block (142) are locked, a limiting groove (144) is formed near the side of the first limiting block (141) and the second limiting block (142). The vertical limiting rib plate (221) is inserted into the aligned limiting groove (144).

6. A shut-off valve according to claim 1 or 5, characterized in that: The lower end of the valve disc (4) is provided with an external threaded connection part, and the lower end of the valve disc (4) is fitted with a non-metallic seal (19) and a valve disc nut (20), and the non-metallic seal (19) is locked by the valve disc nut (20).

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