JPH04134981U - Gate valve seat leakage measuring device - Google Patents

Abstract

(57) [Summary] [Purpose] When the degree of adhesion between the valve body seats 7, 8 and the valve seats 9, 10 decreases and leakage occurs in the sealing fluid in the bonnet 6, this leakage is detected and the leakage is detected. To enable early confirmation of the cause of a decrease in adhesion of a sheet portion. [Structure] A first valve V1 is interposed in the main passage 14B of the seal fluid supply system 14 that supplies seal fluid into the bonnet 6, and the main passage 14B bypasses the first valve V1.
A bypass passage 14C is formed which communicates with
are interposed in series.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention can be used, for example, in piping systems where gas flows in oil refinery plants. This invention relates to a valve seat leakage measuring device for a gate valve.

0002

[Conventional technology]

As shown in FIGS. 3 and 4, this type of gate valve includes a valve box 1, a pair of valve bodies 2, 3, the tip is connected to the valve bodies 2 and 3, and both valve bodies 2 and 3 are moved back and forth at the same time to open and close. An opening/closing mechanism 4 is disposed at the tip of the opening/closing mechanism 4, and the valve bodies 2, 3 are connected to each other as shown in FIG. The wedge 5 is provided with a wedge 5 that biases the valve in the direction of separation (left and right direction in the figure) in the closed position. The opening of the valve stem 4B is inserted through the bonnet 6 in an airtight and slidable manner. Covered airtight. In the valve box 1, one A pair of ring-shaped valve box seats 7 and 8 are arranged opposite each other with wedge-shaped side surfaces. In addition, ring-shaped valve seats 9, corresponding to the valve body seats 7, 8 are provided on the outer surfaces of the valve bodies 2, 3. The configuration includes 10.

0003 The opening/closing mechanism 4 extends downward from a drive source (for example, a hydraulic cylinder) not shown. The piston rod 4A extends from the piston rod 4A and the coupling 11, which can be disassembled vertically, It is composed of the aforementioned valve stem 4B connected to the stone rod 4A. A wedge 5 is disposed at the tip of the valve stem 4B. Wedge 5 is One wedge 5a is arranged on the valve body 2 side with a ball 5A interposed in the center, and the valve body and the other wedge 5b arranged on the 3 side, and the wedge of one wedge 5a The surface corresponds to the slope 2A of the valve body 2, and the wedge surface of the other wedge 5b corresponds to the slope of the valve body 3. Compatible with 3A. In addition, the fluid passing through the piping system connected to the valve box 1, that is, the valve body The fluid passing through the upstream passage 12 and the downstream passage 13 of the valve body contains, for example, toxic gas or flammable gas. If the object is a dangerous object such as a The pressure must be higher than the fluid pressure in the piping system to prevent mixing and explosion. from the sealing fluid supply system 14 using an inert gas (e.g. nitrogen gas) as a sealing fluid. It can be supplied inside the bonnet 6.

0004 The valve bodies 2 and 3 are moved from the fully open position of FIG. 4 to the fully open position of FIG. 3 by the operation of the opening/closing mechanism 4, as shown in FIG. Fully closed position where the lower end comes into contact with the stopper 15 located at the bottom of the valve box 1 and stops It opens and closes by moving back and forth with the stroke amount up to. That is, the valve bodies 2 and 3 are shown in FIG. When in the fully open position at the stroke start end, operate the opening/closing mechanism 4 in the closing direction (lowering direction). By doing so, the valve bodies 2 and 3 simultaneously move (down) in the closing direction. Valve in the process of movement The seats 9 and 10 have wedge-shaped side surfaces and are arranged opposite to each other. Since they locally interfere with each other while undergoing relative displacement, the valve bodies 2 and 3 rotate around the ball 5A. It rotates slightly together with one wedge 5a and the other wedge 5b. valve body Movements 2 and 3 occur at the end of the stroke where the lower end (tip) contacts the stopper 15. The entire circumference of the valve seats 9 and 10 is almost evenly distributed over the entire circumference of the valve box seats 7 and 8. come into contact with In other words, in the fully closed position, the side shape of the valve bodies 2 and 3 is similar to that of the valve body seats 7 and 8. Becomes wedge-shaped to match the wedge-shaped sides. Even after the movement of valve bodies 2 and 3 is completed, there is a slight The opening/closing mechanism 4 moves in the closing direction to close one wedge 5a and the other wedge 5b. Move slightly towards the closing direction. As a result, the wedge surfaces of both wedges 5a and 5b become valves. While pushing the slopes 2A and 3A of the bodies 2 and 3 apart in the direction of separation, the valve bodies 2 and 3 are The sealing fluid that had flowed into the space also acts as a force that pushes the valve bodies 2 and 3 apart in the direction of separation. Therefore, the pressure by the wedges 5a and 5b and the seal fluid pressure load work together. fully closed state in which the entire circumference of the valve seats 9 and 10 is pressed against the entire circumference of the valve box seats 7 and 8. become.

[0005] When the valve bodies 2 and 3 are in the fully closed position at the end of the stroke shown in Fig. 3, the opening/closing mechanism 4 is opened. By operating in the up direction (up direction), the wedges 5a and 5b are first moved in the opening direction. The valve bodies 2 and 3 will move slightly (rise), and immediately after that, the valve bodies 2 and 3 will also begin to move in the opening direction. cormorant As the edges 5a and 5b move, the wedge surfaces of the wedges 5a and 5b move the valve bodies 2 and 3. Although the force that was pushing the slopes 2A and 3A apart becomes a little weaker, the valve bodies 2 and 3 remain in the seal. The valve bodies 2 and 3 move because they are pushed apart in the direction of separation by the load of fluid pressure. The valve seats 9, 10 slide onto the valve body seats 7, 8 by this. In other words, valve bodies 2 and 3 The valve seats 9 and 1 expand in the direction of separation due to movement in the opening direction (upward direction). 0 onto the valve box seats 7 and 8 which are arranged opposite each other and have wedge-shaped side surfaces. The valve will be opened.

[0006] However, with conventional gate valves, due to deterioration over time, for example, the valve bodies 2 and 3 may become completely closed. The degree of adhesion between the valve seats 9, 10 and the valve body seats 7, 8, that is, the degree of adhesion of the valve seats, decreases. Even if there is a leak in the seal fluid inside the bonnet 6, it is possible to know the leak status. Therefore, it is difficult to early confirm the decrease in valve seat adhesion, which is the cause of leakage. The purpose of this study is to consider things such as valve maintenance, determining valve lifespan, and the impact on plant operations. I couldn't do it. Therefore, there are causes that prevent the continuation of proper plant operation. It had become.

[0007]

[Problem that the idea aims to solve]

The problem we are trying to solve is that the tightness of the valve seat is reduced and the seal flow inside the bonnet is reduced. Even if a leak occurs in your body, you may not be able to know the leak condition and may not be able to identify the cause of the leak. The problem is that it is difficult to early confirm that the valve seat has deteriorated in its adhesion.

[0008]

[Means to solve the problem]

The present invention includes a valve body that is moved forward and backward within the valve box by an opening/closing mechanism, and a valve body that is moved forward and backward within the valve box by an opening and closing mechanism. has a valve box seat that is provided in the valve box and moves toward and away from the valve body as the valve body moves forward and backward; A sealing fluid-filled bonnet formed in communication with the valve body and the valve body disposed within the bonnet. Equipped with a seal fluid supply system that supplies seal fluid when the bonnet is fully closed. When the valve body is fully closed, the passage on the upstream side of the valve body and the passage on the downstream side of the valve body are cut off by fluid pressure. In the gate valve, the seal fluid supply system includes a first valve interposed therein. a main passage connected to the main passage, and a bypass formed in communication with the main passage bypassing the first valve. It is equipped with a pass passage, and a bypass passage opening/closing valve and a flow meter are connected in series to this bypass passage. It is characterized by being equipped with

[0009]

[Effect] According to the present invention, the valve body is fully closed, and the seal fluid is supplied from the seal fluid supply system into the bonnet. After the sealing fluid is supplied, the first valve of the main passage is closed at all times or at any time; By opening the bypass passage on-off valve of the bypass passage, the seal inside the bonnet is removed. Fluid leakage can be measured and confirmed with a flow meter.

0010

【Example】

Figure 1 is a longitudinal side view of a gate valve to which the present invention is applied, and Figure 2 is a partially sectional view. It is a front view, and the same or equivalent parts as those of the conventional example shown in FIGS. 3 and 4 have the same parts. Reference numerals are given and detailed explanations are omitted. In Figures 1 and 2, the sheet The fluid supply system 14 is filled with an inert gas (for example, nitrogen gas) as a sealing fluid. The cylinder 14A is connected to the inside of the bonnet 6. In-passage 14B and bypass passage 14C formed in communication with this main passage 14B It is made up of. Upstream of bypass passage 14C in main passage 14B Between the side branching point P1 and the downstream confluence point P2, there is a first valve formed by a solenoid valve or an electric valve. A valve V1 is installed in the bypass passage 14C, and a flowmeter (for example, an electric flowmeter) is installed in the bypass passage 14C. ) 16 is installed, and a solenoid valve or electric valve is installed immediately upstream of this flow meter 16. A second valve V2 of the same structure is installed, and a third valve V3 of the same structure is installed immediately downstream. has been done. These second and third valves V2 and V3 constitute a bypass passage opening/closing valve BV. are doing. Also, the downstream confluence point of the bypass passage 14C in the main passage 14B Connected to the coupling 11 of the opening/closing mechanism 4 between P2 and the entrance P3 of the bonnet 6. The valve is opened when the valve bodies 2 and 3 as shown in FIG. 1 are fully closed, and the valve body 2 and 3 as shown in FIG. Valve V4 that is closed when fully open (e.g. springback angle valve) is provided.

[0011] With such a configuration, the first to third valves V1, V2, V3 and the valves V In the closed state of valve V4, when valve bodies 2 and 3 are fully closed, valve V4 is automatically opened. . When the first valve V1 is opened in this state, the inside of the cylinder 14 of the seal fluid supply system 14 is The sealing fluid is supplied into the bonnet 6 through the main passage 14B. valve body The pressure inside the bonnet 6 is higher than the fluid pressure passing through the upstream passage 12 and the valve body downstream passage 13. By setting the pressure of the supplied sealing fluid high, the valve seats 9, 10 and valve body seats 7 and 8, that is, the valve seat upstream of the valve body. It is possible to prevent the fluids in the side passage 12 and the valve body downstream passage 13 from mixing and causing an explosion. Wear. In this way, the seal fluid is supplied from the seal fluid supply system 14 into the bonnet 6. After the supply, the first valve V1 of the main passage 14B is closed at all times or at any time, and the bypass is closed. The second valve V2 and the third valve V3 of the bypass passage 14C, that is, the bypass passage opening/closing valve BV If the sealing fluid inside the bonnet 6 leaks by opening the valve, The leakage can be measured and confirmed by the flow meter 16. As a result, leakage It is possible to quickly confirm the cause of poor valve seat adhesion, and also to Data for considering maintenance, valve life judgment, impact on plant operations, etc. This makes it possible to collect data, which helps keep the plant running properly.

0012 Note that the first to third valves V1, V2, which are configured by electromagnetic valves or electric valves, V3 may be a manual on-off valve. Also, it is connected to the coupling 11 of the opening/closing mechanism 4. Valve V4, which is opened and closed mechanically, is replaced by a solenoid valve that is opened and closed electrically, or an electric It may also be constituted by a valve. Furthermore, the bypass passage opening/closing valve BV is set to the second and third valves. It may be configured using only either V2 or V3.

[0013]

[Effect of the idea]

As explained above, this invention reduces the closeness of the valve seat and prevents the seal inside the bonnet. Even if a leak occurs in the bypass passage, this leak can be detected by a flow meter installed in the bypass passage. By knowing this, you can quickly check for poor valve seat adhesion, which is the cause of leaks. This allows for maintenance of valves, determination of valve lifespan, and impact on plant operations. It is now possible to collect data to examine the There are benefits that can help you.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of a gate valve to which the present invention is applied.

FIG. 2 is a half-cut front view of a gate valve to which the present invention is applied.

FIG. 3 is a longitudinal sectional side view of a gate valve with a conventional structure.

FIG. 4 is a half-cut front view of a gate valve with a conventional structure.

[Explanation of symbols]

1 Bento box 2,3 Valve body 4 Opening/closing mechanism 6 Bonnet 7,8 Valve box seat 12 Valve body upstream passage 13 Valve body downstream passage 14 Seal fluid supply system 14B Main passage 14C bypass passage 16A flow meter BV bypass passage opening/closing valve V1 first valve

Claims (1)

[Scope of utility model registration request] 1. A valve body that is configured to have a valve body that is moved forward and backward within the valve body by an opening/closing mechanism, and a valve body seat that is provided within the valve body and that moves toward and away from the valve body as the valve body moves forward and backward, and that communicates with the valve body. and a seal fluid supply system that supplies seal fluid when the valve body is fully closed. In a gate valve configured to block an upstream passage and a valve body downstream passage, the seal fluid supply system includes a main passage in which a first valve is interposed;
A gate valve comprising a bypass passage formed in communication with the main passage bypassing the first valve, and a bypass passage opening/closing valve and a flow meter are interposed in series in the bypass passage. Valve seat leakage measuring device.