A self-sealing structure butterfly valve

Abstract

The present invention relates to the field of valves, and specifically discloses a self-sealing structure butterfly valve, which includes a valve body, a first valve seat, a valve stem and a valve plate. The valve body is installed on a pipeline, the first valve seat is arranged inside the valve body, a second valve seat is provided between the valve body and the first valve seat, the valve plate is arranged on the second valve seat, the valve stem is arranged inside the valve plate, a pre-valve cavity is formed among the valve body, the valve plate and the second valve seat, a balance cavity is formed by the valve body, the first valve seat and the second valve seat, and the pipeline has a post-valve cavity; a three-way reversing valve is further arranged on the butterfly valve, and the three-way reversing valve is respectively connected to the pre-valve cavity, the balance cavity and the post-valve cavity. The structure of the present invention is compact, the layout is reasonable and reliable. When the valve is closed, the self-pressure of the medium is used to increase the sealing force. When the valve is opened, the medium pressure pushes the first valve seat away from the sealing surface of the valve plate through a conversion device, reducing the friction force, so that the torque force required by the actuator is small, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of valves, and specifically relates to a butterfly valve with a self-sealing structure. Background Art

[0002] At present, especially in the application fields of medium and large calibers and medium and low pressures, butterfly valves will become the dominant valve type. Existing large-caliber high-pressure butterfly valves have complex structures and require the assistance of tooling during processing. The sealing force and friction force required between the butterfly plate and the valve seat are large. In order to ensure reliable sealing, the actuator must provide a large torque, resulting in high production costs. Summary of the Invention

[0003] The purpose of the present invention is to provide a butterfly valve with a self-sealing structure, which uses the pressure of the medium itself and reduces the torque required by the actuator through the commutation of the three-way commutation valve, thereby reducing the manufacturing cost.

[0004] To solve the above technical problems, the present invention provides a butterfly valve with a self-sealing structure, including a valve body, a first valve seat, a valve stem, and a valve plate. The valve body is installed on a pipeline. The first valve seat is arranged in the valve body. A second valve seat is provided between the valve body and the first valve seat. The valve plate is arranged on the second valve seat. The valve stem is arranged in the valve plate. A pre-valve cavity is formed among the valve body, the valve plate, and the second valve seat. A balance cavity is formed by the valve body, the first valve seat, and the second valve seat. The pipeline has a post-valve cavity. The butterfly valve is also provided with a three-way commutation valve, which is respectively connected to the pre-valve cavity, the balance cavity, and the post-valve cavity, and the three-way commutation valve communicates the pre-valve cavity and the balance cavity or communicates the balance cavity and the post-valve cavity.

[0005] Further, an elastic member is provided between the first valve seat and the second valve seat.

[0006] Further, the second valve seat includes a valve seat body and a valve seat opening protruding from the valve seat body. The valve body is provided with three stepped inner holes that gradually increase in the direction of the pipeline. The valve seat body is closely attached to the second stepped inner hole of the valve body. One end of the first valve seat is closely attached to the inner wall of the valve seat opening, and the other end is fixed on the valve body 1. An elastic member is provided between the end of the first valve seat and the valve seat body.

[0007] Specifically, a first sealing ring is provided between the outer wall of the valve seat body and the valve body.

[0008] Further, the outer wall of the first valve seat is stepped. The first step is inserted into the valve seat opening of the second valve seat. A second sealing ring is provided between the side surface of the first step and the inner wall of the valve seat opening. A third sealing ring is provided between the side surface of the second step and the hole wall of the second stepped inner hole of the inner wall of the valve body. The third step is closely attached to the third stepped inner hole of the inner wall of the valve body.

[0009] Further, a tapered hole is provided on the valve seat body, and the valve plate is arranged in the tapered hole.

[0010] Further, the valve body and the pipeline are fixed by bolts and nuts, and a sealing gasket is provided between the first valve seat and the pipeline.

[0011] Further, the first valve seat and the valve body are fixed by screws.

[0012] Further, the balance cavity is composed of the valve seat bodies of the first valve seat and the second valve seat and the outer wall of the valve seat opening.

[0013] Further, a communication hole is provided on the valve body to communicate the front valve cavity, the balance cavity and the rear valve cavity, and the communication hole is connected to the three-way reversing valve through a connecting pipe.

[0014] The beneficial effects of the present invention are as follows: The structure of the present invention is compact, the layout is reasonable and reliable, and it is applicable to occasions such as large diameter and large pressure difference. The self-sealing principle of the valve is realized by using a three-way reversing valve. By switching the connection and blocking of the valve cavity by the three-way reversing valve, the sealing force is increased by using the medium's own pressure when the valve is closed. When the valve is opened, the medium pressure pushes the first valve seat away from the valve plate sealing surface through the conversion device, reducing the friction force, so that the torque force required by the actuator is small, and the manufacturing cost is reduced. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions of the present invention, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic structural diagram of the butterfly valve of the present invention;

[0017] Figure 2 It is a partially enlarged schematic structural diagram of the butterfly valve of the present invention.

[0018] In the figure: 1-valve body, 2-first valve seat, 3-valve stem, 4-valve plate, 5-second valve seat, 6-elastic member, 7-first sealing ring, 8-second sealing ring, 9-third sealing ring, 10-sealing gasket, 11-pipeline, 12-three-way reversing valve, A-front valve cavity, B-balance cavity, C-rear valve cavity. Detailed Embodiments

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] In a specific embodiment of the present invention, as Figure 1 shown, a self-sealing structure butterfly valve is specifically disclosed, which includes a valve body 1, a first valve seat 2, a valve stem 3 and a valve plate 4. The valve body 1 is installed on a pipeline 11, and the valve body 1 and the pipeline 11 are fixed by bolts and nuts. The first valve seat 2 is arranged at one end of the valve body 1 connected to the pipeline 11, and a sealing gasket 10 is provided between the first valve seat 2 and the pipeline 11.

[0021] The first valve seat 2 is arranged inside the valve body 1, and the first valve seat 2 and the valve body 1 are fixed by screws. A second valve seat 5 is provided between the valve body 1 and the first valve seat 2. The valve plate 4 is arranged on the second valve seat 5, and the valve stem 3 is arranged inside the valve plate 4.

[0022] The second valve seat 5 includes a valve seat body and a valve seat opening protruding from the valve seat body. There are three stepped inner holes in the valve body 1 that gradually increase in the direction of the pipeline. The valve seat body is in close contact with the second stepped inner hole of the valve body 1. A first sealing ring 7 is provided between the outer wall of the valve seat body and the valve body 1. The valve seat body has a tapered hole, and the valve plate 4 is arranged in the tapered hole. One end of the first valve seat 2 is in close contact with the inner wall of the valve seat opening, and the other end is fixed on the valve body 1. The outer wall of the first valve seat 2 is stepped. The first step is inserted into the valve seat opening of the second valve seat 5, and a second sealing ring 8 is provided between the side surface of the first step and the inner wall of the valve seat opening; a third sealing ring 9 is provided between the side surface of the second step and the hole wall of the second stepped inner hole of the inner wall of the valve body (1); the third step is in close contact with the third stepped inner hole of the inner wall of the valve body 1.

[0023] A pre-valve cavity A is formed between the valve body 1, the valve plate 4 and the second valve seat 5; a balance cavity B is formed by the valve body 1, the first valve seat 2 and the second valve seat 5, and the balance cavity B is composed of the valve seat bodies of the first valve seat 2 and the second valve seat 5 and the outer walls of the valve seat ports; the pipeline 11 has a post-valve cavity C; a three-way reversing valve 12 is further provided on the butterfly valve, and the three-way reversing valve 12 is respectively connected to the pre-valve cavity A, the balance cavity B and the post-valve cavity C through pipe fittings, and the three-way reversing valve 12 connects the pre-valve cavity A and the balance cavity B or connects the balance cavity B and the post-valve cavity C. A communication hole communicating the pre-valve cavity A, the balance cavity B and the post-valve cavity C is opened on the valve body, and the communication hole is connected to the three-way reversing valve through a connecting pipe.

[0024] An elastic member 6 is provided between the end of the first valve seat 2 and the second valve seat 5. The elastic member 6 is preferably a spring, and the function of the spring enables the second valve seat 5 to perform axial displacement in the valve body 1.

[0025] When the present invention works, the actuator drives the valve stem 3 to rotate, the valve plate 4 rotates with the valve stem 3, the valve stem 3 disengages from the second valve seat 5 after rotation, and the medium passes through. When the valve is closed, the three-way reversing valve 12 cuts off the communication between the pre-valve cavity A and the post-valve cavity C, and at the same time connects the pre-valve cavity A and the balance cavity B, and uses the self-pressure of the medium to increase the sealing force; when the valve is opened, the three-way reversing valve 12 cuts off the communication between the pre-valve cavity A and the balance cavity B, and at the same time connects the balance cavity B and the post-valve cavity C, so that the balance sealing cavity B is depressurized, and the second valve seat 5 disengages from the valve plate 4 by using the self-pressure of the medium, reducing the friction force with the valve plate; the requirement of valve opening and closing can be satisfied with a smaller torque.

[0026] The specific sealing process and principle are as follows: As Figure 2 shown, P1 is the pre-valve medium pressure, P2 is the post-valve medium pressure, P3 is the spring sealing force, P4 is the balance cavity medium pressure; and it is designed that P1 > P3, and the medium flows from the pre-valve cavity A to the post-valve cavity C.

[0027] When the valve is closed, the three-way reversing valve 12 changes direction to cut off the communication between the N1 and N3 ends, and makes N1 and N2 communicate; the pressures of the pre-valve cavity A and the balance cavity B are balanced, the first valve seat 2 contacts the valve plate 4 under the action of the spring, and the sealing force between the second valve seat 5 and the valve plate 4 is P2 + P3 + P4.

[0028] 1. When the pressure difference is large, P1 >> P2, P2 can be ignored. Because P4 = P1, so P3 + P4 > P1, and reliable sealing can be achieved by using the self-pressure of the medium;

[0029] 2. When the pressure difference is small, P1 ≈ P2, P4 = P1 = P2. At this time, the sealing force acting on the valve plate 4 is the spring sealing force P3, and P2 + P3 + P4 > P1, and reliable sealing can still be achieved;

[0030] When the valve is opened, the three-way reversing valve 1 reverses to cut off the connection between the N1 and N2 ends, and connects the N2 and N3; the cavity C behind the valve is connected to the balance cavity B, and the balance seal cavity B is depressurized, P2 = P4, and the sealing force acting on the first valve seat 3 and the valve plate 4 is P2 + P3 + P4.

[0031] 1. When the pressure difference is large, P1 >> P2, and P2 and P4 can be ignored. Since P1 > P3, under the action of the medium's own pressure, the second valve seat 5 moves axially along the inner wall of the valve body 1 and disengages from the valve plate 4 by itself. The valve plate 4 can open the valve by overcoming the packing friction force;

[0032] 2. When the pressure difference is small, P1 ≈ P2, and P4 = P2 = P1. At this time, the sealing force acting on the valve plate 4 is the spring sealing force P3, and the valve can be opened by overcoming the spring sealing force;

[0033] From the above, it can be obtained that when the valve is closed, using the medium pressure P1, reliable sealing can be achieved only by overcoming the spring thrust; when the valve is opened, under the action of the medium pressure P1, the second valve seat 5 disengages from the valve plate 4 by itself under the action of the medium pressure, and the valve plate overcomes the packing friction force to open; this greatly reduces the actuator thrust, reduces the manufacturing cost, and plays a positive role in improving the market competitiveness of the product.

[0034] The above-disclosed is only a preferred embodiment of the present invention, and of course, it cannot be used to limit the scope of the rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A self-sealing structure butterfly valve, comprising a valve body (1), a first valve seat (2), a valve stem (3) and a valve plate (4), wherein the valve body (1) is installed on a pipeline (11), and the first valve seat (2) is arranged inside the valve body (1), characterized in that, A second valve seat (5) is provided between the valve body (1) and the first valve seat (2). The valve plate (4) is arranged on the second valve seat (5), and the valve stem (3) is arranged inside the valve plate (4). The second valve seat (5) includes a valve seat body and a valve seat opening protruding from the valve seat body. The valve body (1) is provided with three stepped inner holes that gradually increase in the direction of the pipeline, and the valve seat body is in close contact with the second stepped inner hole of the valve body (1). One end of the first valve seat (2) is in close contact with the inner wall of the valve seat opening, and the other end is fixed on the valve body (1). An elastic member (6) is provided between the end of the first valve seat (2) and the valve seat body. A pre-valve cavity (A) is formed among the valve body (1), the valve plate (4) and the second valve seat (5), and a balance cavity (B) is formed by the valve body (1), the first valve seat (2) and the second valve seat (5). The pipeline (11) has a post-valve cavity (C). The elastic member (6) is a spring, the pre-valve medium pressure is greater than the spring sealing force, and the medium flow direction is from the pre-valve cavity (A) to the post-valve cavity (C). A three-way reversing valve (12) is further provided on the butterfly valve. The three-way reversing valve (12) is respectively connected to the pre-valve cavity (A), the balance cavity (B) and the post-valve cavity (C). The three-way reversing valve (12) connects the pre-valve cavity (A) and the balance cavity (B) or connects the balance cavity (B) and the post-valve cavity (C). When the valve is closed, the three-way reversing valve (12) cuts off the connection between the pre-valve cavity (A) and the post-valve cavity (C), and at the same time connects the pre-valve cavity (A) and the balance cavity (B) to increase the sealing force by using the medium's own pressure. When the valve is opened, the three-way reversing valve (12) cuts off the connection between the pre-valve cavity (A) and the balance cavity (B), and at the same time connects the balance cavity (B) and the post-valve cavity (C) to relieve the pressure in the balance sealing cavity (B).

2. The self-sealing structure butterfly valve according to claim 1, characterized in that, A first sealing ring (7) is provided between the outer wall of the valve seat body and the valve body (1).

3. The self-sealing structure butterfly valve according to claim 1, characterized in that, The outer wall of the first valve seat (2) is stepped. The first step is inserted into the valve seat opening of the second valve seat (5), and a second sealing ring (8) is provided between the side surface of the first step and the inner wall of the valve seat opening. A third sealing ring (9) is provided between the side surface of the second step and the hole wall of the second stepped inner hole of the inner wall of the valve body (1). The third step is in close contact with the third stepped inner hole of the inner wall of the valve body (1).

4. The self-sealing structure butterfly valve according to claim 1, characterized in that, The valve seat body has a tapered hole, and the valve plate (4) is arranged in the tapered hole.

5. The self-sealing structure butterfly valve according to claim 1, characterized in that, The valve body (1) and the pipeline (11) are fixed by bolts and nuts, and a sealing gasket (10) is provided between the first valve seat (2) and the pipeline (11).

6. The self-sealing structure butterfly valve according to claim 1, characterized in that, The first valve seat (2) and the valve body (1) are fixed by screws.

7. The self-sealing structure butterfly valve according to claim 3, characterized in that, The balance cavity (B) is composed of the valve seat body of the first valve seat (2) and the second valve seat (5) and the outer wall of the valve seat opening.

8. The self-sealing structure butterfly valve according to claim 1, characterized in that, A communication hole communicating the pre-valve cavity (A), the balance cavity (B) and the post-valve cavity (C) is opened on the valve body, and the communication hole is connected to the three-way reversing valve through a connecting pipe.

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