An online maintenance system for power plant gate valves

Abstract

This invention relates to an online maintenance gate valve for a power station. The gate valve includes a valve body with two movable valve seats inside. Each movable valve seat has a seat channel, and an elastic sealing structure is provided between each movable valve seat and the valve body. A gate is located inside the valve body between the two movable valve seats, and the gate has a closed position and an open position. A limiting plate is located inside the valve body between the two movable valve seats, with one end of the limiting plate pressing against the end face of one movable valve seat and the other end pressing against the end face of the other movable valve seat. The limiting plate is located on the extension line of the gate's closed path. When the gate is in the closed position, the limiting plate is in contact with or has a gap with the end of the gate. When the gate moves from the closed position to the open position, the sealing surfaces between the gate and each movable valve seat partially contact and seal. At this time, due to the presence of the limiting plate, the two movable valve seats will not be misaligned, ensuring that the sealing effect between the movable valve seats and the valve body remains intact. The limiting plate does not affect the opening and closing of the gate, making it convenient to use.

Description

Technical Field

[0001] This invention relates to the field of valves, and more specifically to an online maintenance power station gate valve. Background Technology

[0002] Gate valves are widely used in many fields, such as power plants, water plants, and oil transportation. A gate valve generally consists of a valve body containing two movable valve seats. A gate is positioned between the two movable valve seats within the valve body, and a gate drive mechanism is also installed on the valve body. A sealing surface exists between the gate and the two movable valve seats to prevent the medium from entering the valve cavity through the gap between the gate and the movable valve seats. An elastic sealing structure exists between the movable valve seats and the valve body to prevent the medium from entering the valve cavity through the gap between the movable valve seats and the valve body. However, during the opening process, the gate partially separates from the two movable valve seats, and this separation gradually increases as the gate opens. Under the action of the elastic sealing structure between the movable valve seats and the valve body, the movable valve seats on both sides may become misaligned in the parts not in contact with the gate, causing the seal between the movable valve seats and the valve body to fail. This allows the medium to enter the valve cavity, contaminating the valve cavity and causing coking inside the valve cavity, hindering gate movement, reducing valve lifespan, and decreasing market competitiveness. Summary of the Invention

[0003] The purpose of this invention is to provide an online maintenance power plant gate valve to solve the problem in the prior art where the movable valve seat deviates during the gate opening process, leading to sealing failure between the movable valve seat and the valve body.

[0004] To achieve the above objectives, the present invention provides an online maintenance power station gate valve with the following technical solution: An online maintenance power station gate valve includes a valve body, inside which are two movable valve seats, each with a valve seat channel. An elastic sealing structure is provided between each movable valve seat and the valve body. A gate is provided inside the valve body between the two movable valve seats, and a sealing surface is provided between the gate and each movable valve seat. The gate has a closed position for blocking the valve seat channel and an open position for opening the valve seat channel. A limiting plate is provided inside the valve body between the two movable valve seats, with one end of the limiting plate pressing against the end face of one movable valve seat and the other end pressing against the end face of the other movable valve seat. The limiting plate is located on the extension line of the gate's closing path. When the gate is in the closed position, the limiting plate is in contact with or has a gap with the end of the gate.

[0005] The limiting plate is movably mounted on the valve body along the valve seat axis.

[0006] The limiting plate is provided with a stepped hole. A screw for connecting to the valve body is installed in the small diameter section of the stepped hole. A support ring is fitted outside the screw in the small diameter section. One end of the support ring presses against the valve body, and the other end extends from the small diameter section into the large diameter section. There is a gap between the outer surface of the support ring and the inner wall of the small diameter hole. A washer is provided between the head end of the screw and the end of the support ring. The outer diameter of the washer is larger than the inner diameter of the small diameter section and smaller than the inner diameter of the large diameter section.

[0007] The elastic sealing structure includes a spring seat disposed between the movable valve seat and the valve body and a sealing ring disposed between the spring seat and the movable valve seat. A spring is disposed on the spring seat, with one end of the spring mounted on the spring seat and the other end pressing against the valve body.

[0008] The movable valve seat has a guide section that is installed to guide the valve body along the valve seat axis, an installation section for guiding the installation of the sealing ring, and a tapered transition section located between the guide section and the installation section. The outer surface of the sealing ring is adapted to the inner wall of the valve body. The sealing ring has a wedge-shaped surface that is adapted to the outer surface of the tapered transition section. The sealing ring also has a V-shaped groove facing the spring seat. The spring seat has a pressing protrusion that engages with the V-shaped groove and can radially press against the two groove walls of the V-shaped groove when the spring seat and the sealing ring move towards each other.

[0009] The valve body has a maintenance channel opposite to the gate. The maintenance channel has an inspection port and a self-sealing structure is provided inside the maintenance channel. The limiting plate is provided on the self-sealing structure.

[0010] The self-sealing structure includes a support located in the maintenance channel, a sealing ring located between the support and the inner wall of the maintenance channel, and a traction seat connected to the support for pressing the sealing ring. The traction seat and the valve body have a limiting structure, and the limiting plate is set on the support.

[0011] The support has a guide section that mates with the maintenance passage and a tapered section facing the traction seat. The sealing ring has an inclined surface that matches the outer side of the tapered section. A ring gasket is also provided in the maintenance passage on the side of the sealing ring facing the traction seat. The support also has a ring gasket mounting section for installing the ring gasket. A four-open ring is provided in the maintenance passage on the side of the ring gasket facing the traction seat. A limit ring is provided between the traction seat and the four-open ring.

[0012] The limiting structure includes an annular limiting protrusion at the end of the traction seat, a limiting step at the inspection port that cooperates with the annular limiting protrusion, and a limiting ring between the four-ring and the annular limiting protrusion.

[0013] The traction seat and the support are connected by bolts.

[0014] The beneficial effects of this invention are as follows: When the gate is in the closed position, the sealing surfaces between the gate and each movable valve seat are in full contact. When the gate moves from the closed position to the open position, the sealing surfaces between the gate and each movable valve seat partially contact and seal. At this time, due to the presence of the limit plate, the two movable valve seats will not be deflected, ensuring that the sealing effect between the movable valve seat and the valve body will not fail. Moreover, the limit plate does not affect the opening and closing of the gate, making it convenient to use.

[0015] Furthermore, the limiting plate is movably mounted on the valve body along the valve seat axis. Under the action of the medium, the two movable valve seats can move synchronously, preventing the medium from leaking into the valve cavity between the movable valve seat downstream of the medium flow direction and the limiting plate.

[0016] Furthermore, the maintenance access and self-sealing structure allow the gate valve to be easily installed without the entire gate valve being disassembled when the movable valve seat needs to be replaced. After the new movable valve seat is placed, a telescopic jacking member is inserted through the maintenance access to push the two movable valve seats apart, allowing the gate valve to be easily installed between the two movable valve seats. Moreover, the self-sealing structure ensures the sealing effect of the valve body. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a structural embodiment of an online maintenance power station gate valve according to the present invention;

[0018] Figure 2 yes Figure 1 A magnified view of a section at point A in the middle;

[0019] Figure 3 yes Figure 2 A magnified view of a section at point B in the middle;

[0020] Figure 4 yes Figure 2 A magnified view of a section at point C;

[0021] Figure 5 yes Figure 4 A magnified view of a section at point D. Detailed Implementation

[0022] An embodiment of the present invention for online maintenance of a power plant gate valve, as follows: Figures 1-5As shown, the valve includes a valve body 1 with a valve body flow channel 2. Two movable valve seats 3 are disposed inside the valve body, each with a seat passage 4 communicating with the valve body flow channel. An elastic sealing structure is provided between each movable valve seat and the valve body. A gate 5 is disposed between the two movable valve seats inside the valve body. A sealing surface 6 is provided between the gate and each movable valve seat. The sealing surface can be a hard alloy layer disposed on the two surfaces of the gate, or a hard alloy layer disposed on the end face of each movable valve seat, or a hard alloy layer disposed on both the gate and the end face of the movable valve seats. The gate has a closed position for blocking the seat passage and an open position for opening the seat passage. The valve body has an upper valve chamber. When the gate is open, it enters the upper valve chamber. The directions of up, down, left, and right, as defined in the attached drawings, do not necessarily represent the actual installation direction of the gate valve. They are only for clearly illustrating the structure of the gate valve and do not limit its protection range.

[0023] A limiting plate 7 is provided between two movable valve seats 3 inside the valve body. One end of the limiting plate presses against the end face of one movable valve seat, and the other end presses against the end face of the other movable valve seat. The limiting plate is located on the extension line of the gate's closing path. When the gate is in the closed position, there is a gap between the end of the limiting plate and the gate. In this embodiment, for ease of describing the structure of the gate valve, the description is based on the direction defined above. The limiting plate is located below the gate. When the gate is in the open position, the lower end of the gate moves upward. When fully open, the lower end of the gate completely avoids the valve seat passage, but the two plate surfaces at the lower end of the gate are still in sealing contact with the upper parts of the movable valve seats on both sides. The dimension of the limiting plate 7 along the axial direction of the valve seat passage is equal to the sum of the dimensions of the gate and the sealing surface along the axial direction of the valve seat passage.

[0024] The limiting plate 7 is movably mounted on the valve body along the valve seat axis. The limiting plate has a stepped hole, through which a screw 30 for connection to the valve body is inserted. A support ring 31 is fitted around the screw in the small-diameter section 29 of the stepped hole. One end of the support ring presses against the valve body, and the other end extends from the small-diameter section into the large-diameter section 28. A gap 34 exists between the outer surface of the support ring and the inner wall of the small-diameter hole. In this embodiment, the gap between the outer surface of the support ring and the inner wall of the small-diameter hole is 1 mm. A washer 32 is placed between the head of the screw and the end of the support ring. The outer diameter of the washer is larger than the inner diameter of the small-diameter section but smaller than the inner diameter of the large-diameter section. If the limit plate is fixedly installed on the valve body, when the gate is opened, the downstream moving valve seat will be subjected to the force of the medium. At this time, the downstream moving valve seat will separate from the limit plate, and the medium will enter the lower valve chamber. Since the upper and lower valve chambers are connected, if a large amount of medium enters, it will also enter the upper valve chamber, which may affect the operation of the gate over a long period of time.

[0025] The resilient sealing structure includes a spring seat 9 disposed between the movable valve seat 3 and the valve body, and a sealing ring 8 disposed between the spring seat 9 and the movable valve seat 3. A spring 16 is disposed on the spring seat, with one end of the spring mounted on the spring seat and the other end pressing against the valve body. The movable valve seat has a guide section 10 that guides the valve body to move along the valve seat axis, an installation section 11 for guiding the installation of the sealing ring, and a tapered transition section 12 located between the guide section and the installation section. The outer surface of the sealing ring is adapted to the inner wall of the valve body. The sealing ring has a wedge-shaped surface 13 that is adapted to the outer surface of the tapered transition section. The sealing ring also has a V-groove 14 facing the spring seat. The spring seat has a pressing protrusion 15 that mates with the V-groove and can radially press against the two groove walls of the V-groove when the spring seat and the sealing ring move towards each other. Regardless of whether the movable valve seat is subjected to the impact or recoil force of the medium, the sealing ring will deform radially when the movable valve seat or the spring seat presses against the sealing ring, thus ensuring the sealing performance between the movable valve seat and the valve body.

[0026] A maintenance channel is provided on the valve body opposite the gate. The maintenance channel has an inspection port and a self-sealing structure is provided inside the maintenance channel. A limiting plate is provided on the self-sealing structure. The self-sealing structure includes a support 17 located in the maintenance channel, a sealing ring 19 located between the support and the inner wall of the maintenance channel, and a traction seat 35 connected to the support for pressing the sealing ring. A limiting structure is provided between the traction seat and the valve body. The limiting plate 7 is provided on the support by the aforementioned screws and 30. The support has a guide section 18 that guides the maintenance channel and a tapered section 21 facing the traction seat. The sealing ring has an inclined surface that adapts to the outer surface of the tapered section. A ring gasket 20 is also provided in the maintenance channel on the side of the sealing ring facing the traction seat. The support also has a ring gasket mounting section 22 for installing the ring gasket. A four-open ring 23 is provided in the maintenance channel on the side of the ring gasket facing the traction seat. A limiting ring 24 is provided between the traction seat and the four-open ring. The four-ring structure is a circular ring divided into four segments, each crescent-shaped. The four rings are embedded in an annular groove on the inner wall of the maintenance channel on the valve body. The limiting structure includes an annular limiting protrusion 25 at the end of the traction seat, a limiting step 26 at the maintenance port that cooperates with the annular limiting protrusion, and a limiting ring between the four-ring and the annular limiting protrusion. The traction seat and the support are connected by bolts 27. The maintenance channel and self-sealing structure allow for easy installation of the gate without disassembling the entire gate valve when replacing the movable valve seat. After inserting the new movable valve seat, a telescopic pressure member is inserted through the maintenance channel to push the two movable valve seats apart, allowing the gate to be easily installed between them. The self-sealing structure ensures the sealing effect of the valve body.

[0027] During use, when the gate is in the closed position, the sealing surfaces between the gate and each movable valve seat are in full contact, ensuring a tight seal. As the gate moves from the closed to the open position, the sealing surfaces between the gate and each movable valve seat initially begin to seal, and the contact area gradually decreases as the opening degree increases. When the gate fully opens the valve seat passage, the two lower plates of the gate seal against the upper parts of the two movable valve seats. At this point, the two ends of the limit plate engage with the lower parts of the two movable valve seats for limiting and positioning. Due to the presence of the limit plate, during the gate opening process, the upper parts of the two movable valve seats are in close contact with the gate, and the lower parts of the two movable valve seats can move synchronously with the limit plate. Therefore, the two movable valve seats will not skew, and the limit plate does not affect the opening and closing of the gate, making it convenient to use.

[0028] In other embodiments of the present invention, the gap between the outer side of the support ring and the inner wall of the small diameter hole can also be adjusted according to actual needs; when the sealing performance between the limiting plate and the movable valve seat is not affected, the limiting plate can also be fixed; when the gate is in the closed position, the ends of the limiting plate and the gate can contact each other without a gap.

Claims

1. An online maintenance gate valve for a power station, comprising a valve body, wherein two movable valve seats are disposed inside the valve body, each movable valve seat having a valve seat passage, and an elastic sealing structure is provided between each movable valve seat and the valve body; a gate plate is disposed inside the valve body between the two movable valve seats, and a sealing surface is provided between the gate plate and each movable valve seat; the gate plate has a closed position for blocking the valve seat passage and an open position for opening the valve seat passage, characterized in that: A limiting plate is provided between two movable valve seats inside the valve body. One end of the limiting plate presses against the end face of one movable valve seat, and the other end presses against the end face of the other movable valve seat. The limiting plate is located on the extension line of the gate's closing path. When the gate is in the closed position, the limiting plate is in contact with the end of the gate or has a gap. The limiting plate is movably installed on the valve body along the valve seat axis. The limiting plate is provided with a stepped hole, and a screw for connecting to the valve body is inserted in the small-diameter section of the stepped hole. A support ring is fitted around the outside of the screw. One end of the support ring presses against the valve body, and the other end extends from the small-diameter hole section into the large-diameter hole section. There is a gap between the outer surface of the support ring and the inner wall surface of the small-diameter hole. A washer is provided between the head end of the screw and the end of the support ring. The outer diameter of the washer is larger than the inner diameter of the small-diameter hole section but smaller than the inner diameter of the large-diameter hole section. A maintenance channel is provided on the valve body opposite to the gate. The maintenance channel has a maintenance port and a self-sealing structure is provided inside the maintenance channel. A limiting plate is provided on the self-sealing structure.

2. The online maintenance power station gate valve according to claim 1, characterized in that: The elastic sealing structure includes a spring seat disposed between the movable valve seat and the valve body and a sealing ring disposed between the spring seat and the movable valve seat. A spring is disposed on the spring seat, with one end of the spring mounted on the spring seat and the other end pressing against the valve body.

3. The online maintenance power station gate valve according to claim 2, characterized in that: The movable valve seat has a guide section that is installed to guide the valve body along the valve seat axis, an installation section for guiding the installation of the sealing ring, and a tapered transition section located between the guide section and the installation section. The outer surface of the sealing ring is adapted to the inner wall of the valve body. The sealing ring has a wedge-shaped surface that is adapted to the outer surface of the tapered transition section. The sealing ring also has a V-shaped groove facing the spring seat. The spring seat has a pressing protrusion that engages with the V-shaped groove and can radially press against the two groove walls of the V-shaped groove when the spring seat and the sealing ring move towards each other.

4. The online maintenance power station gate valve according to claim 1, characterized in that: The self-sealing structure includes a support located in the maintenance channel, a sealing ring located between the support and the inner wall of the maintenance channel, and a traction seat connected to the support for pressing the sealing ring. The traction seat and the valve body have a limiting structure, and the limiting plate is set on the support.

5. The online maintenance power station gate valve according to claim 4, characterized in that: The support has a guide section that mates with the maintenance passage and a tapered section facing the traction seat. The sealing ring has an inclined surface that matches the outer side of the tapered section. A ring gasket is also provided in the maintenance passage on the side of the sealing ring facing the traction seat. The support also has a ring gasket mounting section for installing the ring gasket. A four-open ring is provided in the maintenance passage on the side of the ring gasket facing the traction seat. A limit ring is provided between the traction seat and the four-open ring.

6. The online maintenance power station gate valve according to claim 5, characterized in that: The limiting structure includes an annular limiting protrusion at the end of the traction seat, a limiting step at the inspection port that cooperates with the annular limiting protrusion, and a limiting ring between the four-ring and the annular limiting protrusion.

7. The online maintenance power station gate valve according to claim 4, characterized in that: The traction seat and the support are connected by bolts.

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