A sealed self-compensating high-temperature butterfly valve

Abstract

The sealed self-compensating high-temperature butterfly valve is mainly composed of a valve body seat, a valve plate, a valve stem, a main actuator and an auxiliary actuator, a shaft end sealing mechanism, a guide sleeve, a guide block, a connecting plate, and a connecting head; the high-temperature butterfly valve is an eccentric structure, that is, the center line of the valve stem shaft deviates from the center line of the sealing surface; the main actuator drives the valve plate to rotate through the valve stem to achieve the adjustment function; the valve stem is installed on the high-pressure side, and the valve plate is installed on the low-pressure side. A small oil cylinder mechanism is arranged on both sides of the valve plate, and both sides are connected to the auxiliary actuator through a connecting plate and a connecting head. The auxiliary actuator pushes the valve stem through the guide block to achieve horizontal movement of the valve plate, thereby realizing the cut-off sealing function, and the shaft end sealing is achieved through the shaft end sealing mechanism. The high-temperature butterfly valve decomposes the valve adjustment and cut-off action into two actions of adjustment and cut-off sealing, thereby avoiding the butterfly valve from getting stuck under high-temperature conditions and improving the service life of the valve.

Description

Technical Field

[0001] The invention belongs to the technical field of valves, and in particular relates to a sealed self-compensating high-temperature butterfly valve. Background Art

[0002] Among various types of valves, butterfly valve is the most widely used one. The butterfly valve has a simple structure, small size and light weight. Its structural principle is suitable for making large-caliber valves. At the same time, it has good flow regulation characteristics. Therefore, it has been widely used in petrochemical, metallurgical steelmaking, water treatment, electric power and other industries. Especially in high-temperature, large-caliber pipelines with high sealing requirements, three-eccentric butterfly valves are widely used. The biggest feature of the three-eccentric butterfly valve is that it fundamentally changes the sealing structure. It is no longer a position seal, but a torsion seal, which completely relies on the contact surface pressure of the valve seat to achieve the sealing effect. Therefore, the problem of zero leakage of the metal valve seat is solved in one fell swoop, and because the contact surface pressure is proportional to the medium pressure, the high pressure and high temperature resistance are also solved. Due to the innovative structural characteristics of the three-eccentric butterfly valve, in various process pipelines, whether it is a switch valve or a regulating valve, in theory, as long as the selection is appropriate, it can be used with confidence.

[0003] However, the three-eccentric butterfly valve also has some disadvantages, such as high processing accuracy requirements, strict size matching and clearance requirements, and after a certain period of use, it will be affected by high temperature deformation and fatigue loss, resulting in reduced valve sealing performance and difficulty in achieving the theoretical zero sealing effect. At present, the three-eccentric butterfly valve is basically imported in China, and it is difficult for domestic production to meet the requirements in terms of clearance matching and processing accuracy, which has a certain impact on the safe and long-term operation of the device.

[0004] Patent CN201822060360.7 provides a three-eccentric butterfly valve, including a valve body and a valve stem rotatably connected to the valve body at both ends, a flow channel is provided inside the valve body, a disc plate fixedly connected to the valve stem is provided inside the flow channel, and the disc plate can rotate in the flow channel with the valve stem; a first seal that can form a sealing fit with the flow channel of the valve body is provided on one end face of the disc plate, and a fastener connecting the first seal and the disc plate is also provided; a pressure ring is provided on the end face of the first seal away from the disc plate, and a positioning member is provided between the first seal and the pressure ring; a sealing gasket is provided between the disc plate and the first seal.

[0005] Patent CN201420448622.6 provides a three-eccentric butterfly valve, including a valve body, a valve stem and a valve plate. The valve stem is located in the valve body and both ends of the valve stem extend out of the valve body. The valve plate is located in the valve body and is fixedly connected to the valve stem. The end of the valve plate has an annular step 1 and annular step 2 arranged in a stepped manner from the inside to the outside. The annular step 2 is embedded with an annular pressure ring and an annular groove is formed between the inner wall of the pressure ring and the annular step 1. An annular seal is arranged in the groove. The outer edge of the seal is conical and the diameter of the cone gradually increases inward. The inner side of the valve body has a boss coaxially arranged with the valve body and the inner edge of the boss matches the outer edge of the seal. The top and bottom of the seal respectively have an annular recess 1 and annular recess 2 coaxially arranged with the seal. Recess 1 and recess 2 are respectively communicated with the inner cavity of the valve body.

[0006] The above two types of three-eccentric butterfly valves rely on torsion sealing. The valve cut-off and sealing are only achieved through the rotation of the valve, and the sealing is achieved by the contact surface pressure of the valve seat. However, the valve processing accuracy is high, the seal uses elastic elements, the structure is complex, there is a risk of parts wear and fall off, and the valve is affected by high temperature deformation and fatigue loss, resulting in reduced valve sealing performance and other problems.

[0007] In the field of petrochemical industry, a large number of imported three-eccentric butterfly valves are used under large-caliber and high-temperature conditions. These butterfly valves are not only expensive to purchase, have a long purchase cycle, and are difficult to maintain and overhaul, but also have reduced sealing performance after a certain period of use, and cannot achieve complete cut-off. Therefore, it is of great practical significance to develop a new butterfly valve with low processing requirements, good sealing effect and high temperature resistance. Summary of the invention

[0008] In order to solve the technical problems in the prior art that butterfly valves have high machining accuracy requirements, complex structures, and are affected by high-temperature deformation and fatigue loss, resulting in reduced valve sealing performance, the present invention provides a sealed self-compensating high-temperature butterfly valve.

[0009] A sealed self-compensating high-temperature butterfly valve provided by the present invention is mainly composed of a valve body seat, a valve plate, a valve stem, a main actuator and an auxiliary actuator, an axial end sealing mechanism, a guide sleeve, a guide block, a connecting plate, and a connecting head; the high-temperature butterfly valve is an eccentric structure; the valve seat is arranged in the inner cavity of the valve body, and the valve stem and the valve plate are fixedly connected and placed in the valve body; the main actuator drives the valve plate to rotate through the valve stem to realize the regulating function; the valve stem is installed on the high-pressure side, and the valve plate is installed on the low-pressure side. An auxiliary actuator is connected to both sides of the valve plate through the connecting plate and the connecting head to ensure the synchronization of horizontal movement. The auxiliary actuator pushes the valve stem through the guide block to realize the horizontal movement of the valve plate, thereby realizing the cutting and sealing function; the axial end sealing mechanism is located on both sides of the valve stem. The expansion joint assembly is composed of an expansion joint, a stuffing box assembly and a purge port; the expansion joint assembly is composed of an expansion joint, an inlet end ring, an outlet end ring, a guide tube and a purge port, one side of the inlet end ring is connected to the valve body, and the other side is connected to the expansion joint and the outlet end ring in sequence and then connected to the guide block, the guide tube is welded to the inlet end ring and is arranged on the inner side of the expansion joint, and a purge port is arranged at the inlet end ring, and the purge can prevent the medium from entering and play a role in cooling the valve stem, and the expansion joint can withstand lateral displacement and axial displacement; the stuffing box assembly is composed of a purge sleeve, a high-temperature disc spring, a stuffing box and a stuffing gland, one end of the stuffing box is overlapped with the purge sleeve, a high-temperature disc spring is arranged in the middle, and the other end is welded to the outlet end ring, a stuffing is placed inside, and is connected to the stuffing gland by bolts.

[0010] As an improved solution, the sealing form between the valve body and the valve plate is a flat seal; the valve stem and the valve plate are key-connected for transmission, which is convenient for processing and assembly and disassembly; the axial hole part of the valve body is a waist-shaped hole, and a boss design is added to the valve seat. The inner surface of the valve plate is arc-shaped, and welding is adopted between the high-temperature butterfly valve and the pipeline.

[0011] As a further improved solution, a positioning pin is provided at the stuffing box flange connection to prevent the stuffing box from rotating; a limit pin is provided on the valve body seat as a mechanical limit for the valve closing position of the auxiliary actuator to facilitate processing and assembly and disassembly.

[0012] As a further improved solution, the eccentric structure of the high temperature butterfly valve is a single eccentric structure, that is, the center line of the valve stem axis deviates from the center line of the sealing surface;

[0013] The present invention has applications in fields including but not limited to petroleum, chemical industry, and water conservancy.

[0014] The working principle of a sealed self-compensating high-temperature butterfly valve provided by the present invention is:

[0015] The sealed self-compensating high-temperature butterfly valve decomposes the previous valve adjustment and cutting action into two actions: adjustment and sealing cutting. Before the valve is opened, the auxiliary actuator first drives the valve plate to move horizontally away from the valve seat sealing surface and lock it, and then the main actuator drives the valve to perform normal adjustment. When the valve closing signal is received, the valve performs a rotary valve closing action. Only after receiving the valve closing signal can the valve plate be pushed horizontally to fit the valve seat and seal, ensuring the valve sealing performance. When the valve is closed, the valve seat and the valve plate are in an overlapping form, and there are no problems such as centering and jamming caused by thermal expansion. At the same time, a boss design is added to the valve seat. When the valve body and the valve plate sealing surface are closed to zero degrees, the valve seat boss surface is flush with the valve plate, further reducing the valve leakage.

[0016] The present invention has the following beneficial effects:

[0017] 1) The unique structure of the sealed self-compensating high-temperature butterfly valve reduces the requirements for valve manufacturing accuracy and the processing technology is relatively simple;

[0018] 2) The sealed self-compensating high-temperature butterfly valve decomposes the previous valve adjustment and cutting action into two actions: adjustment and cutting sealing. It can play the dual role of adjustment and cutting, separate the valve adjustment process from the cutting sealing process, avoid the butterfly valve from getting stuck under high temperature conditions, and increase the service life of the valve;

[0019] 3) When the sealed self-compensating high-temperature butterfly valve receives a valve closing signal, the valve performs a rotary valve closing action. The valve plate can only be pushed horizontally to fit and seal with the valve seat after receiving the valve closing signal, thereby ensuring the sealing performance of the valve. At the same time, a boss design is added to the valve seat. When the valve body and the valve plate sealing surface are closed to zero degrees, the valve seat boss surface is flush with the valve plate, further reducing the valve leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a front view of a sealed self-compensating high-temperature butterfly valve of the present invention;

[0021] Figure 2 A top view (including a partial cross-sectional view) of a sealed self-compensating high-temperature butterfly valve of the present invention;

[0022] Figure 3 It is a schematic diagram of an expansion joint assembly of the present invention;

[0023] Figure 4 It is a schematic diagram of the horizontal closing valve of the present invention (excluding the actuator);

[0024] Figure 5 This is a schematic diagram of the rotary valve opening of the present invention (excluding the actuator).

[0025] In the figure: 1-valve body and seat, 2-valve plate, 3-valve stem, 4-expansion joint, 5-stuffing box, 6-limit pin, 7-guide sleeve, 8-guide block, 9-purge port, 10-connecting plate, 11-connector, 12-main actuator, 13-auxiliary actuator, 14-purge sleeve, 15-high-temperature disc spring, 16-packing, 17-packing gland, 18-inlet end ring, 19-outlet end ring, 20-guide tube, 21-locating pin. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings.

[0027] like Figures 1 to 3 As shown, a sealed self-compensating high-temperature butterfly valve provided by the present invention is mainly composed of a valve body and seat 1, a valve plate 2, a valve stem 3, an expansion joint 4, a stuffing box 5, a limit pin 6, a guide sleeve 7, a guide block 8, a purge port 9, a connecting plate 10, a connecting head 11, a main actuator 12, an auxiliary actuator 13, a purge sleeve 14, a high-temperature disc spring 15, a packing 16, a packing gland 17, an inlet end ring 18, an outlet end ring 19, a guide tube 20 and a positioning pin 21; the sealed self-compensating high-temperature butterfly valve is an eccentric structure, which decomposes the adjustment and cutting action into two actions of adjustment and cutting off the seal. The valve seat is arranged in the inner cavity of the valve body, the valve stem 3 is fixedly connected to the valve plate 2 and placed in the valve body, and the main actuator 12 drives the valve plate 2 to rotate through the valve stem 3 to realize the adjustment function; an auxiliary actuator 13 is connected to both sides of the valve plate 2 through a connecting plate 10 and a connecting head 11 to push the valve stem 3 to ensure the synchronization of horizontal movement, thereby realizing the valve cut-off seal; the auxiliary actuator 13 drives the guide block 8 to push the expansion joint assembly and the stuffing box assembly of the valve through the guide sleeve 7 to realize the axial end sealing of the valve, and the axial end sealing mechanism of the valve is realized by the joint action of the expansion joint assembly, the stuffing box assembly and the purge port 9.

[0028] The high temperature butterfly valve of the present invention is a single eccentric structure, that is, the center line of the valve stem axis deviates from the center line of the sealing surface. Figures 4-5As shown, the eccentricity a between the center line of the valve stem shaft and the center line of the sealing surface is related to the horizontal offset b of the valve plate and the inner diameter c of the valve body. The eccentricity a between the center line of the valve stem shaft and the center line of the sealing surface should be determined by comprehensively considering the valve size and the horizontal offset of the valve plate; at the same time, the design of the valve seat boss is added to the valve seat. When the valve seat and the valve plate sealing surface are closed to zero degrees, the valve seat boss surface is flush with the valve plate surface, reducing the valve leakage; the valve seat and the valve plate are sealed in a plane seal; the inner surface of the valve plate is arc-shaped, and the shaft hole of the valve body is a waist-shaped hole. A positioning pin 21 is set between the stuffing box and the shell to prevent the stuffing box from rotating; the high-temperature butterfly valve is provided with a limit pin 6 on the valve body as a mechanical limit of the valve closing position of the auxiliary actuator; the valve plate 2 is installed on the low-pressure side, and the valve stem 3 is installed on the high-pressure side. The valve stem 3 and the valve plate 2 are connected by a key transmission, which is convenient for processing and assembly and disassembly; a purge port 9 is set on the inlet end ring 18 of the expansion joint assembly to prevent the medium from entering the stuffing box assembly and cool the valve stem at the same time. The butterfly valve and the pipeline are welded. Before the high-temperature butterfly valve is opened, the auxiliary actuator 13 first drives the valve plate 2 to move horizontally away from the valve seat sealing surface and then locks the position, and then the main actuator 12 drives the valve to perform normal adjustment action; when receiving the valve closing signal, the valve performs a rotary valve closing action. Only after receiving the valve closing signal, the auxiliary actuator 13 can push the valve plate 2 horizontally into the valve seat to fit and seal with the valve seat to ensure the valve sealing performance.

[0029] The above is only a typical example of the present invention and does not impose any formal limitation on the present invention. Any technician familiar with the profession, without departing from the scope of the technical solution of the present invention, shall regard any changes or modifications made by using the above technical content as equivalent examples of equivalent changes. Any equivalent changes made to the above examples based on the technical essence of the present invention without departing from the content of the technical solution of the present invention, such as improvements in the valve plate form, the eccentricity between the center line of the valve stem shaft and the center line of the sealing surface, and the horizontal offset size of the valve plate, etc., shall also be regarded as falling within the scope of protection of the present invention.

Claims

1. A sealed self-compensating high-temperature butterfly valve, characterized in that: The high-temperature butterfly valve is mainly composed of a valve body seat, a valve plate, a valve stem, a main actuator, an auxiliary actuator, a shaft end sealing mechanism, a guide sleeve, a guide block, a connecting plate and a connector; the high-temperature butterfly valve is an eccentric structure; the main actuator drives the valve plate to rotate through the valve stem, the valve stem is installed on the high-pressure side, and the valve plate is installed on the low-pressure side. An auxiliary actuator is connected to both sides of the valve plate through a connecting plate and a connector to ensure the synchronization of horizontal movement. The auxiliary actuator pushes the valve stem through the guide block to achieve horizontal movement of the valve plate, thereby realizing the cut-off sealing function; the shaft end sealing mechanism is located on both sides of the valve stem, and is composed of an expansion joint assembly, a stuffing box assembly, and a sealing ring assembly. The expansion joint assembly is composed of an expansion joint, an inlet end ring, an outlet end ring, a guide tube and a purge port. One side of the inlet end ring is connected to the valve body, and the other side is connected to the expansion joint and the outlet end ring in sequence and then connected to the guide block. The guide tube is welded to the inlet end ring and is arranged on the inner side of the expansion joint. A purge port is arranged at the inlet end ring. The expansion joint can withstand lateral displacement and axial displacement. The stuffing box assembly is composed of a purge sleeve, a high-temperature disc spring, a stuffing box and a stuffing gland. One end of the stuffing box is overlapped with the purge sleeve, a high-temperature disc spring is arranged in the middle, and the other end is welded to the outlet end ring. A stuffing is placed inside and connected to the stuffing gland by bolts.

2. The sealed self-compensating high-temperature butterfly valve according to claim 1, characterized in that: The sealing form between the valve body, valve seat and valve plate is a plane seal.

3. The sealed self-compensating high-temperature butterfly valve according to claim 1 is characterized in that: The shaft hole of the valve body is a waist-shaped hole, and a boss is added to the valve body seat.

4. The sealed self-compensating high-temperature butterfly valve according to claim 1, characterized in that: The inner surface of the valve plate is arc-shaped.

5. The sealed self-compensating high-temperature butterfly valve according to claim 1, characterized in that: The high-temperature butterfly valve and the pipeline are welded.

6. The sealed self-compensating high-temperature butterfly valve according to claim 1, characterized in that: A positioning pin is arranged at the connection of the stuffing box flange; and a limit pin is arranged on the valve body seat as a mechanical limit of the valve closing position of the auxiliary actuator.

7. The sealed self-compensating high-temperature butterfly valve according to claim 1, characterized in that: The eccentric structure of the high-temperature butterfly valve is a single eccentric structure.

8. The sealed self-compensating high-temperature butterfly valve according to claim 1, characterized in that: The valve stem and the valve plate are connected and driven by a key.

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