JPH1038095A - Gate valve for high temperature - Google Patents

Abstract

(57) [Problem] To provide a valve box by loosely fitting an inner cylinder in an outer cylinder, and to have a ring-shaped elasticity between the outer cylinder and the inner cylinder for holding the inner cylinder with respect to the outer cylinder. In a high temperature gate valve provided by connecting a body to an inner peripheral portion of an outer cylinder and an outer peripheral portion of an inner cylinder, thermal stress of a spring member can be reduced. A spring (10) is configured to expand and contract along a direction in which an inner cylinder (4) is relatively displaced with respect to an outer cylinder (2) due to a difference in thermal expansion or contraction between an outer cylinder (2) and an inner cylinder (4). According to this configuration, since the direction of expansion and contraction of the spring 10 is the same as the direction of displacement of the inner cylinder 4, the thermal stress generated in the spring 10 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate valve used for a high-temperature fluid.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a general gate valve 41 does not have a structure that absorbs a dimensional change of a valve box 42 and the like accompanying a change in fluid temperature and a heat transfer coefficient of the fluid. Therefore, in the closed state, the valve seat 43 and the valve body 44 may bite and cause malfunction.

For this reason, for example, as shown in FIG.
The valve body 44 is divided into an upstream side and a downstream side, and one of the divided valve bodies
Coil spring 45 between 44a and the other split valve element 44b
Was inserted. According to such a structure, the valve box is changed according to the change in the fluid temperature and the heat transfer coefficient of the fluid.
If the dimension of the valve box 42 and the like changes, the coil spring 45 bends and the distance between the two split valve bodies 44a and 44b expands and contracts. Various other high-temperature gate valves have also been proposed, such as a valve box caused by a difference in thermal expansion or contraction between the vicinity of the flow path inside the valve box and the outer peripheral portion, or a difference in thermal expansion between the upstream and downstream sides of the valve box. The valve was designed to absorb the distortion of the valve body. However, in the gate valve shown in FIG. 4, there is no optimum material for the coil spring 45 at high temperatures, and in other gate valves, a large force is required for the opening operation in a state where the valve body is bent, or at high temperatures. There was a problem that the valve body was plastically deformed.

On the other hand, the present inventors have disclosed in Japanese Patent Application No. 7-152093 a valve box 42 composed of an outer cylinder 49 and an inner cylinder 50 as shown in FIG. A ring-shaped spring 51 connected to the inner peripheral portion of the outer cylinder 49 and the outer peripheral portion of the inner cylinder 50 is fitted between the outer cylinder 49 and the sealing member 5 for sealing between the outer cylinder 49 and the inner cylinder 50.
A high-temperature gate valve 41 provided with 2, 53 was proposed. According to this configuration, with the change in the fluid temperature and the heat transfer coefficient of the fluid, a difference in thermal expansion or contraction occurs between the outer cylinder 49 and the inner cylinder 50 of the valve box 42, or the upstream side and the downstream side of the valve box 42 If there is a difference in thermal expansion or contraction on the side, the spring 51 bends and absorbs the difference in thermal expansion or contraction, so that it is possible to prevent the valve box 42 from being overly distorted, thereby ensuring stable operability and sealing. Can be realized.

[0005]

However, in the above-described structure in which the difference in thermal expansion or contraction between the outer cylinder 49 and the inner cylinder 50 is absorbed by the spring 51, the inner cylinder 50 is in the radial direction and the pipe direction. Since the ring-shaped spring 51 expands or contracts in two directions, the displacement direction to be absorbed by the ring-shaped spring 51 extends in two directions, the thermal stress of the spring member 51 increases, and plastic deformation may occur.

An object of the present invention is to solve the above problems and to provide a high temperature gate valve capable of reducing the thermal stress of a spring member.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, a high temperature gate valve according to the present invention comprises an outer cylinder and an inner cylinder which is loosely fitted in the outer cylinder and has a valve channel. A ring-shaped elastic body, which is constituted by a cylinder and holds the inner cylinder with respect to the outer cylinder between the outer cylinder and the inner cylinder, is connected to the inner periphery of the outer cylinder and the outer periphery of the inner cylinder. In the provided high-temperature gate valve, the elastic body is:
The inner cylinder is configured to expand and contract along a direction in which the inner cylinder is relatively displaced with respect to the outer cylinder due to a difference in thermal expansion or contraction between the outer cylinder and the inner cylinder.

More specifically, a convex elastic body mounting portion is formed on each of the inner peripheral portion of the outer cylinder and the outer peripheral portion of the inner cylinder, and each elastic body mounting portion has a seat parallel to the direction of displacement of the elastic body. A surface is formed, and an elastic body end is joined to the seat surface.

Alternatively, a convex elastic body mounting portion is formed on each of the inner peripheral portion of the outer cylinder and the outer peripheral portion of the inner cylinder, and each elastic body mounting portion is provided with a seat along a direction intersecting the direction of displacement of the elastic body. A surface is formed, and an elastic body end is joined to the seat surface.

According to the above configuration, when the inner cylinder is displaced relative to the outer cylinder due to the difference in thermal expansion or contraction, the elastic body expands and contracts to absorb the difference in thermal expansion or contraction. At this time, since the direction of expansion and contraction of the elastic body is the same as the direction of displacement of the inner cylinder, the thermal stress generated in the elastic body is reduced as compared with the conventional case.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a valve box, which is composed of an outer cylinder 2 and an inner cylinder 4 having a valve box flow path 3 loosely fitted inside the outer cylinder 2. Flanges 5 are provided at both ends of the outer cylinder 2. At the center of the outer cylinder 2, there is provided a cylindrical valve body storage part 7 having a valve body storage space 6 inside.

At both end surfaces of the outer cylinder 2, disk-shaped end walls 8 projecting toward the center from the inner peripheral surface of the outer cylinder 2 to the outer peripheral surfaces of both ends of the inner cylinder 4 are formed. A pair of disk-shaped intermediate walls 9 projecting outward from the inner peripheral surface of the outer cylinder 2 toward the outer peripheral surface of the outer cylinder 2 are formed on the outer peripheral surface of the central part of the inner cylinder 4. The distance between the two intermediate walls 9 is substantially the same as the width of the valve body storage space 6 in the flow path direction.

A pair of ring-shaped springs 10 (an example of an elastic body) that expands and contracts in the direction indicated by arrow A are fitted between the outer cylinder 2 and the inner cylinder 4. The direction indicated by the arrow A indicates that a thermal expansion difference occurs between the inner cylinder 4 and the outer cylinder 2 or a thermal expansion difference occurs between the upstream side and the downstream side of the inner cylinder 4 or the outer cylinder 2. This is a direction in which the inner cylinder 4 is relatively displaced with respect to the outer cylinder 2, and is a direction obtained by combining the movement of the fixed point on the inner cylinder 4 in the radial direction and the movement in the pipeline direction.

On the outer peripheral surface of the inner cylinder 4, a first mounting portion 11, which has a seat surface 11 a parallel to the direction of arrow A and protrudes outward, is formed over the entire periphery. A second protruding inwardly having a bearing surface 12a parallel to the direction of arrow A.
The mounting portion 12 is formed over the entire circumference, and the inner peripheral portion of each spring 10 is connected to the first mounting portion 11 by a plurality of countersunk screws 13 while being joined to the bearing surface 11a. Is seat surface 12
In a state joined to a, it is connected to the second mounting portion 12 by a plurality of flat head screws 13.

Between each spring 10 and the first mounting portion 11, each spring 10
The first packing 14 and the second packing 15 seal the entire space between the first mounting portion 12 and the second mounting portion 12, respectively. The first packing 14 and the second packing 15 are an example of a sealing material for sealing between the outer cylinder 2 and the inner cylinder 4, and the first packing 14
14 is a graphite-based (eg, graphite) packing having a low thermal conductivity, and the second packing 15 is a metal-based packing having a high thermal conductivity.

Further, between the outer cylinder 2 and the inner cylinder 4, the outer cylinder 2 is provided.
A first heat insulating material storage space 17 surrounded by an end inner peripheral surface, an end outer peripheral surface of the inner cylinder 4, and opposed end walls 8 and springs 10 is formed over the entire circumference. A second heat insulating material storage space 18 surrounded by a central inner peripheral surface of the outer cylinder 2, a central outer peripheral surface of the inner cylinder 4, and opposing intermediate wall 9 and spring 10 is formed over the entire circumference. . Each of the first heat insulating material storage space 17 and the second heat insulating material storage space 18 has a first heat insulating material 19.
(Glass wool) and the second heat insulating material 20 (glass wool) are stored.

Further, inside the valve box 1, a valve body storage space 6 is provided.
A valve body 22 is provided through a valve rod 21 inserted through the valve body 22. The valve element 22 is openable and closable between a valve seat 23 provided in the center of the inner cylinder 4 and between the two intermediate part walls 9 and the valve element storage space 6. In addition, a driving device 24 for moving the valve rod 21 in the opening and closing direction of the valve element 22 is provided at an end of the valve element storage section 7.
The valve stem 21 is linked to a driving device 24 via a driving shaft 25.

The operation of the above configuration will be described below.
When a high-temperature fluid flows through the valve case flow path 3, a difference in thermal expansion between the inner cylinder 4 and the outer cylinder 2 occurs due to a change in the fluid temperature and the heat transfer coefficient of the fluid. Alternatively, when a thermal expansion difference occurs between the upstream side and the downstream side of the outer cylinder 2, the inner cylinder 4 is relatively displaced with respect to the outer cylinder 2, but the displacement occurs substantially in the direction indicated by arrow A, and The displacement of the inner cylinder 4 is absorbed by the contraction (extension) of the spring 10. As a result, it is possible to prevent excessive strain from occurring in the valve box 1, and to maintain stable sealing properties and operability. Spring at this time
Since the contraction direction of the spring 10 is substantially a predetermined direction, the thermal stress generated in the spring 10 can be reduced more than the thermal stress generated in the conventional spring shown in FIG. 5, and plastic deformation of the spring 10 hardly occurs.

Since the first packing 14 has a low thermal conductivity, the heat of the inner cylinder 4 is hardly transmitted to the spring 10, and
Since the packing 15 has a high thermal conductivity, the heat of the spring 10 is released to the outer cylinder 2 through the second packing 15. From this,
Even if a high-temperature fluid flows, the temperature of the spring 10 relatively decreases,
Further, the first heat insulating material 19 and the second heat insulating material 20
Is provided, the spring 10 is not directly exposed to the high-temperature fluid, so that the temperature of the spring 10 can be further reduced. As a result, the design temperature of the spring 10 can be reduced, so that the selection of the material is facilitated and the design is simplified.

A first heat insulating material is provided between the outer cylinder 2 and the inner cylinder 4.
Since the 19 and the second heat insulating material 20 are enclosed, the temperature of the outer cylinder 2 can be lower than that of the inner cylinder 4. As a result, the design temperature of the outer cylinder 2 can be lowered, so that the design is simplified.

As shown in FIG. 2, the first mounting portion 11 protruding toward the outer periphery having a seat surface 11a on the outer peripheral surface of the inner cylinder 4 along a direction intersecting the direction indicated by the arrow A. Is formed over the entire circumference, and a second mounting portion 12 is formed on the inner circumference of the outer cylinder 2 and has a seating surface 12a extending in a direction intersecting with the direction indicated by the arrow A and extending over the entire circumference. Then, with the inner peripheral portion of each spring 10 joined to the seat surface 11a, the first mounting portion 11
The same effect as described above can be obtained by connecting the spring 10 to the second mounting portion 12 in a state where the outer peripheral portion of each spring 10 is joined to the bearing surface 12a. In this case, the thermal stress generated in the spring 10 is smaller than that described above, and the plastic deformation of the spring 10 is less likely to occur.

In the above-described embodiment, the gate valve that opens and closes the valve element 22 using the driving device 24 (electrically driven, hydraulically driven, or air-driven) has been described. Good.

In the above embodiment, glass wool is used as the first heat insulating material 19 and the second heat insulating material 20, but an air layer or a castable refractory material may be used. In the above embodiment, the connection portion of the valve box 1 is in the form of the flange 5, but may be of the butt welding type or the insertion welding type.

In the above embodiment, the two springs 10 are distributed on both front and rear sides with the valve body 22 as a center, but one spring 10 may be provided on only one of the front and rear sides.

[0025]

As described above, according to the present invention, as the fluid temperature and the heat transfer coefficient of the fluid change, a difference in thermal expansion or contraction occurs between the inner cylinder and the outer cylinder of the valve box, or the valve does not move. Even if there is a difference in thermal expansion between the upstream side and the downstream side of the box, the elastic body contracts and absorbs the difference in thermal expansion or contraction. Operability and operability can be maintained. At this time, since the elastic body contracts in a predetermined direction provided to contract, the thermal stress generated in the elastic body is reduced as compared with the conventional one, and plastic deformation of the elastic body is less likely to occur.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a high-temperature gate valve according to an embodiment of the present invention.

FIG. 2 is a sectional view of a high-temperature gate valve according to another embodiment of the present invention.

FIG. 3 is a partial sectional view of a conventional gate valve.

FIG. 4 is a sectional view of a conventional gate valve in which a valve element is divided.

FIG. 5 is a sectional view of a conventional gate valve of a type in which a difference in thermal expansion or contraction is absorbed by a spring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve case 2 Outer case 3 Valve case flow path 4 Inner case 10 Spring (elastic body) 11 First mounting part 11a Seat surface 12 Second mounting part 12a Seat surface

Claims (3)

[Claims] 1. A valve box comprising an outer cylinder and an inner cylinder having a valve box flow passage that is loosely fitted in the outer cylinder, and is provided between the outer cylinder and the inner cylinder with respect to the outer cylinder. In a high-temperature gate valve provided by connecting a ring-shaped elastic body holding the inner cylinder to the inner peripheral portion of the outer cylinder and the outer peripheral portion of the inner cylinder, the elastic body is configured to heat the outer cylinder and the inner cylinder. A high-temperature gate valve having a shape that expands and contracts in a direction in which an inner cylinder is relatively displaced with respect to an outer cylinder due to a difference in expansion or contraction. 2. A convex elastic body mounting portion is formed on each of an inner peripheral portion of an outer cylinder and an outer peripheral portion of an inner cylinder, and a seat surface parallel to a displacement direction of the elastic body is formed on each elastic body mounting portion. 2. The high temperature gate valve according to claim 1, wherein an elastic body end is joined to the seat surface. 3. A convex elastic body mounting portion is formed on an inner peripheral portion of the outer cylinder and an outer peripheral portion of the inner cylinder, and each elastic body mounting portion is provided with a seat along a direction intersecting the direction of displacement of the elastic body. The high-temperature gate valve according to claim 1, wherein a surface is formed, and an elastic body end is joined to the seat surface.