A bidirectional equal pressure zero leakage eccentric butterfly valve

Abstract

The present invention relates to the field of valve technology, and specifically to a bidirectional isobaric zero-leakage eccentric butterfly valve, which solves the problem that the sealing ring of current butterfly valve products is affected by the structure and has a short service life, comprising: a valve body, a fluid channel is provided in the valve body; a valve stem, the valve stem is inserted into the valve body; a butterfly plate, the butterfly plate is installed on the valve stem to cooperate with the valve body to realize the opening and closing of the fluid channel; the valve body is provided with an opening and closing member for driving the valve stem to drive the butterfly plate to rotate; the valve stem is arranged away from the center of the butterfly plate, and the center of the valve stem is offset to the center of the fluid channel; when the butterfly valve is opened, the butterfly plate as a whole does not contact the valve body.

Description

Technical Field

[0001] The invention relates to the technical field of valves, and in particular to a bidirectional equal-pressure zero-leakage eccentric butterfly valve. Background Art

[0002] A butterfly valve, also known as a flap valve, is a regulating valve with a simple structure. It can be used for on-off control of low-pressure pipeline media. A butterfly valve refers to a valve in which the closing member (valve disc or butterfly plate) is a disc that rotates around the valve axis to achieve opening and closing.

[0003] In the prior art, there is a linear butterfly valve, that is, a non-eccentric butterfly valve, such as Figure 1 As shown, it shows the structure in the closed state, the valve stem 1' and the butterfly plate 2' are both located at the center of the pipeline, and the action line of the butterfly plate 2' is a circular motion track 3' with the valve stem 1' as the center; Figure 2 As shown, it is a commonly used single eccentric butterfly valve structure, the center position of the valve stem 1' is offset from the sealing surface of the valve, and a convex portion 3' is provided on the valve body (or valve seat) to cooperate with the sealing of the butterfly plate 2';

[0004] But in the above structure, if Figure 3 , Figure 4 As shown in the figure, it is a state diagram of the central linear butterfly valve and the single eccentric butterfly valve when they are opened. When this structure is opened, the sealing ring on the butterfly plate 2' and the valve body (or valve seat) still have contact points a' and b' located near the two ends of the valve stem 1', which makes the positions of these two points always in a state of friction. The negative effect brought about is not only that the service life of the sealing ring on the butterfly plate 2' will be reduced, but also it will directly lead to great inconvenience in repairing or replacing the sealing ring. Summary of the invention

[0005] Therefore, the present invention provides a bidirectional isobaric zero-leakage eccentric butterfly valve, which solves the problem that the sealing ring of the current butterfly valve product is affected by the structure and has a short service life.

[0006] To achieve the above object, the present invention is achieved through the following technical solutions:

[0007] A bidirectional equal pressure zero leakage eccentric butterfly valve, comprising:

[0008] A valve body, wherein a fluid passage is formed in the valve body;

[0009] A valve stem, the valve stem being inserted into the valve body;

[0010] A butterfly plate, the butterfly plate is mounted on the valve stem to cooperate with the valve body to realize the opening and closing of the fluid channel;

[0011] The valve body is provided with an opening and closing member for driving the valve stem to drive the butterfly plate to rotate;

[0012] The valve stem is arranged offset from the center of the butterfly plate, and the center of the valve stem is offset from the center of the fluid channel;

[0013] When the butterfly valve is opened, the butterfly plate as a whole does not contact the valve body.

[0014] Preferably, the valve body is provided with a sealing surface which is sealed with the butterfly plate, and a sealing member which is used for sealing with the sealing surface is installed on the butterfly plate through a sealing pressure plate, and the cross section of the sealing member has an embedded portion embedded between the butterfly plate and the sealing pressure plate and an extended portion which extends outward and contacts with the sealing surface;

[0015] When the butterfly valve is closed, the extension portion contacts the sealing surface, and a side of the extension portion close to the sealing pressure plate forms a breathing cavity for fluid to enter.

[0016] Preferably, the sealing surface is provided with a copper alloy or a nickel-chromium alloy.

[0017] Preferably, the valve stem comprises an upper valve stem located at the upper end of the butterfly plate and a lower valve stem located at the lower end of the butterfly plate.

[0018] Preferably, the butterfly plate is plug-mounted on the upper valve stem and the lower valve stem respectively, and is fixedly connected by at least one positioning pin.

[0019] Preferably, the opening and closing member is a worm gear assembly.

[0020] Preferably, the opening and closing member is connected to a hand wheel for driving the transmission thereof.

[0021] By adopting the above technical solution, the beneficial effects of the present invention are:

[0022] This technical solution designs a different eccentric structure, which is different from the traditional non-eccentric and eccentric butterfly valve designs. When the butterfly valve is opened, the entire butterfly plate does not contact the valve body at the sealing position, which makes the seal on the butterfly plate in a free state without force when it is opened. The seal reduces the length of time it is subjected to force, thereby correspondingly extending its service life. At the same time, during maintenance, the seal in a free state is easy to inspect and replace, and there is no need to disassemble the entire butterfly plate. It is flexible to use and is conducive to maintenance and initial installation and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the closed state of the mid-line butterfly valve (valve stem axial direction);

[0024] Figure 2 This is a schematic diagram of the structure of the central linear butterfly valve when it is open (the valve stem is vertical);

[0025] Figure 3 It is a schematic diagram of the structure of the existing eccentric butterfly valve when it is closed (valve stem axial direction);

[0026] Figure 4 It is a schematic diagram of the structure of the existing eccentric butterfly valve when it is opened (the valve stem is vertical);

[0027] Figure 5 This is a schematic diagram of the structure of a butterfly valve according to an embodiment of the present invention;

[0028] Figure 6 for Figure 5 A schematic diagram of the local enlarged structure at point A in the middle;

[0029] Figure 7 This is a schematic diagram of the structure of the butterfly valve in a closed state according to an embodiment of the present invention;

[0030] Figure 8 It is a schematic diagram of the state structure of the butterfly valve when it is opened according to an embodiment of the present invention.

[0031] Figure numerals: 1. valve stem; 11. bottom cover; 12. pressure cover; 13. positioning pin; 2. butterfly plate; 21. sealing pressure plate; 22. sealing member; 221. embedded portion; 222. extension portion; 223. breathing chamber; 3. valve body; 31. sealing surface; 4. opening and closing member; 41. hand wheel. DETAILED DESCRIPTION

[0032] The following will describe the implementation methods of the present invention in detail in conjunction with specific embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0033] Example

[0034] refer to Figures 5 to 8 , a bidirectional equal pressure zero leakage eccentric butterfly valve, comprising:

[0035] A valve body 3, wherein a fluid passage is provided in the valve body 3;

[0036] The valve stem 1 is inserted into the valve body 3; wherein the valve stem 1 comprises an upper valve stem 1 located at the upper end of the butterfly plate 2 and a lower valve stem 1 located at the lower end of the butterfly plate 2; the valve stem 1 of the split structure can be easily installed, and the lower valve stem 1 is inserted through the opening at the bottom and fixed by the bottom cover 11; the upper valve stem 1 is fixed by the gland 12, and the upper end of the upper valve stem 1 continues to extend upward; specifically, the butterfly plate 2 is respectively plugged and installed on the upper valve stem 1 and the lower valve stem 1, and is fixedly connected by at least one locating pin 13; wherein the upper valve stem 1 adopts a structure of two locating pins 13 to realize a double positioning and fixing structure, thereby ensuring installation accuracy;

[0037] A butterfly plate 2, wherein the butterfly plate 2 is mounted on the valve stem 1 to cooperate with the valve body 3 to realize the opening and closing of the fluid passage; specifically, a sealing surface 31 is provided on the valve body 3 to seal with the butterfly plate 2, and a sealing member 22 for sealing with the sealing surface 31 is installed on the butterfly plate 2 through a sealing pressure plate 21, and the cross section of the sealing member 22 includes an embedding portion 221 embedded between the butterfly plate 2 and the sealing pressure plate 21 and an extending portion 222 extending outward to contact with the sealing surface 31;

[0038] The valve body 3 is provided with an opening and closing member 4 for driving the valve stem 1 to drive the butterfly plate 2 to rotate; wherein the opening and closing member 4 is a worm gear assembly; the worm gear assembly is connected to a hand wheel 41 that drives the transmission thereof, and the valve is opened and closed by rotating the hand wheel 41; this embodiment shows the most basic structure of the valve, and the above structure can also be replaced by a corresponding known structure, adopting an electric control opening and closing or other transmission structure, etc.;

[0039] Structurally, the valve stem 1 is arranged away from the center of the butterfly plate 2, and the center of the valve stem 1 is offset to the center of the fluid passage; under this design, when the butterfly valve is opened, the butterfly plate 2 as a whole does not contact the valve body 3; the non-contact here means Figure 7 , Figure 8 As shown, when the butterfly plate 2 rotates, it deviates from the motion track 3' of the traditional eccentric butterfly valve. After opening, the butterfly plate 2 moves as a whole to the side away from the sealing surface 31 to realize a structure in which the whole does not contact the valve body 3. The upper and lower ends of the butterfly plate 2 can also be used for fluid to pass through. This structure adopts an optimized double eccentric structure design. When the butterfly plate 2 is opened at a very small angle, the butterfly plate 2 has already separated from the valve body 3, and the seal 22 is no longer stressed and relaxes, thereby reducing the friction of the seal 22 and extending the service life of the valve.

[0040] The structure of the seal 22 is designed with the mounting structure of the butterfly plate 2. When the butterfly valve is closed, the extension 222 contacts the sealing surface 31, and the side of the extension 222 close to the sealing pressure plate 21 forms a breathing cavity 223 for fluid to enter. In actual use, a two-way pressure-bearing design is formed: the design of the seal 22 ensures that when the valve plate is closed, the two-way 1:1 equal pressure is beared;

[0041] In principle:

[0042] The positive seal relies on the worm gear assembly to drive the valve stem 1 to rotate, and the seal 22 on the driving butterfly plate 2 gradually fits with the sealing surface 31 of the valve body 3. Finally, under the action of the medium pressure, the butterfly plate 2 is pushed and the rubber expands until it fits completely and achieves complete sealing.

[0043] The reverse seal relies on the medium to achieve the sealing effect. When the medium pressure acts on the breathing cavity 223 formed between the outer extension part 222 of the sealing surface 31 and the valve body 3, the extension part 222 expands the outer side of the seal 22 under the action of the medium pressure, and gradually fits with the valve body 3 until it is completely sealed. The greater the reverse pressure, the better the reverse sealing effect, the more reliable the sealing, the smaller the torque, and the easier it is to open and close.

[0044] At the same time, the structural design is also carried out for the sealing surface 31: copper alloy or nickel-chromium alloy is arranged on the sealing surface 31. In production, the copper alloy or nickel-chromium alloy is configured by surfacing process, which greatly reduces the friction coefficient between the seal 22 and the sealing surface 31, reduces the friction of the sealing surface 31, increases the service life of the seal 22, and also extends the service life of the valve, reducing the torque.

[0045] The present technical solution designs a different eccentric structure, which is different from the traditional non-eccentric and eccentric butterfly valve designs. When the butterfly valve is opened, the entire butterfly plate 2 does not contact the valve body 3 at the sealing position, which makes the seal 22 on the butterfly plate 2 in a free state without force when it is opened. The seal 22 reduces the time of being subjected to force, thereby correspondingly extending the service life. At the same time, during maintenance, the seal 22 in a free state is easy to inspect and replace, and there is no need to disassemble the entire butterfly plate 2. It is flexible to use and is conducive to maintenance and initial installation and use.

[0046] This technical solution does not describe other necessary components of the valve, such as bearings and sleeves for the rotation of the valve stem 1, which are not the main improvement points of this technology. In production, in order to further improve the service life, all valve fasteners can be made of stainless steel when selecting materials, so as to avoid corrosion of the fasteners due to oxidation reaction with air, which becomes a factor affecting the life of the valve.

[0047] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A bidirectional equal pressure zero leakage eccentric butterfly valve, comprising: A valve body (3), wherein a fluid passage is provided in the valve body (3); A valve stem (1), wherein the valve stem (1) is inserted into the valve body (3); A butterfly plate (2), wherein the butterfly plate (2) is mounted on the valve stem (1) to cooperate with the valve body (3) to realize opening and closing of the fluid passage; The valve body (3) is provided with an opening and closing member (4) for driving the valve stem (1) to drive the butterfly plate (2) to rotate; Features: The valve stem (1) is arranged offset from the center of the butterfly plate (2), and the center of the valve stem (1) is offset from the center of the fluid channel; When the butterfly valve is opened, the butterfly plate (2) as a whole does not contact the valve body (3).

2. A bidirectional isobaric zero-leakage eccentric butterfly valve according to claim 1, characterized in that: The valve body (3) is provided with a sealing surface (31) which is in sealing cooperation with the butterfly plate (2); a sealing member (22) which is in sealing cooperation with the sealing surface (31) is installed on the butterfly plate (2) via a sealing pressure plate (21); the cross section of the sealing member (22) comprises an embedding portion (221) which is embedded between the butterfly plate (2) and the sealing pressure plate (21) and an extending portion (222) which extends outwards and contacts the sealing surface (31); When the butterfly valve is closed, the extension portion (222) contacts the sealing surface (31), and a breathing cavity (223) for fluid to enter is formed on one side of the extension portion (222) close to the sealing pressure plate (21).

3. A bidirectional isobaric zero-leakage eccentric butterfly valve according to claim 2, characterized in that: The sealing surface (31) is provided with a copper alloy or a nickel-chromium alloy.

4. A bidirectional isobaric zero-leakage eccentric butterfly valve according to claim 1, characterized in that: The valve stem (1) comprises an upper valve stem (1) located at the upper end of the butterfly plate (2) and a lower valve stem (1) located at the lower end of the butterfly plate (2).

5. A bidirectional isobaric zero-leakage eccentric butterfly valve according to claim 4, characterized in that: The butterfly plate (2) is respectively plugged and installed on the upper valve stem (1) and the lower valve stem (1), and is fixedly connected via at least one positioning pin (13).

6. A bidirectional isobaric zero-leakage eccentric butterfly valve according to any one of claims 1 to 5, characterized in that: The opening and closing member (4) is a worm gear assembly.

7. A bidirectional isobaric zero-leakage eccentric butterfly valve according to any one of claims 1 to 5, characterized in that: The opening and closing member (4) is connected to a hand wheel (41) for driving the transmission thereof.

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