JPH0611057A - Non-return valve - Google Patents

Abstract

PURPOSE:To enlarge the opening of a valve body at beginning of vapour transport by providing a movable member in response to temperature to energize the valve body in the direction of opening a valve at low temperature. CONSTITUTION:An annular groove is formed on the inner end of an inlet side member outside a valve seat 5, and a coil-like shape memory alloy 12, a movable member in response to temperature, is arranged between the groove and the front face of a valve body 7. When the temperature of liquid is reached to the decided value, the alloy 12 is inverse-transformed from martensite phase to mother phase so as to be into a short memorized form, retreated from the extreme end face of the valve sheet 5 so as to be independent of the motion of the valve body 7, When the fluid pressure at an inlet 3 is higher than that at an outlet 4, the valve body 7 compresses an outlet spring 9 so as to move on the outlet side and open the valve. When the fluid pressure at the outlet 4 is higher than that at the inlet 3, the valve body 7 receives the fluid pressure and the action of the coil spring 9 so as to move on the inlet side and airtightly contact with the valve seat 5. Thus, water or air of low temperature can be quickly discharged so as to shorten a build up time, because the movable member 12 in response to temperature largely opens the valve at low temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve attached to a pipe to allow a fluid to flow in one direction but to stop the flow in the opposite direction, and more particularly to a check valve attached to a steam piping system. A check valve forms an inlet and an outlet by valve casing, a valve seat is provided between the inlet and the outlet, a valve element is arranged on the outlet side of the valve seat, and the flow from the inlet to the outlet is allowed and the reverse direction. There are various types such as swing type and lift type. In both types, the desired seal effect can be obtained by the self-weight of the valve body itself without the fluid pressure acting. In particular, in order to obtain a more reliable seal effect, the valve body is biased by a spring toward the valve seat.

[0002]

2. Description of the Related Art An example of a spring-biased check valve is a fully open sho-1.
No. 0964. The valve casing forms an inlet and an outlet, an annular valve seat is provided between the inlet and the outlet, and a disc-shaped valve element is arranged on the outlet side of the annular valve seat. A coil spring is arranged between them to urge the valve element toward the valve seat. Due to the self-weight of the valve body and the biasing force of the coil spring, the valve can be reliably closed without the fluid pressure, that is, the reverse flow from the outlet to the inlet can be reliably stopped.

[0003]

When the above-mentioned check valve is attached to a steam piping system and used, there is a problem that a desired flow rate cannot be obtained at the beginning of steam transportation. This is because at the beginning of steam transportation, the fluid pressure on the inlet side is low, so that the weight of the valve body itself and the force of the spring cannot be overcome, and the opening degree of the valve body is small.

Therefore, a technical problem of the present invention is to increase the opening degree of the valve body at the beginning of steam transportation in the check valve attached to the steam piping system.

[0005]

The technical means of the present invention taken to solve the above technical problems is to form an inlet and an outlet by valve casing and to form a valve seat between the inlet and the outlet. Provided,
A valve element is arranged on the outlet side of the valve seat, and a check valve that allows flow from the inlet to the outlet and stops flow in the opposite direction is equipped with a temperature responsive member that urges the valve element in the valve opening direction at low temperatures. It is a thing.

[0006]

The operation of the above technical means is as follows.
At the beginning of steam transportation, the piping system is at a low temperature, and the temperature responsive member urges the valve body in the valve opening direction to open the valve body largely. Therefore, the valve body does not become a flow resistance, and a desired flow rate can be obtained. Then, when hot condensate or steam flows in, the temperature responsive member is deformed and does not participate in the valve body, and functions as a normal check valve.

[0007]

EXAMPLE An example showing a concrete example of the above technical means will be described (see FIG. 1). The valve casing is made by screwing the inlet side member 1 and the outlet side member 2 with a gasket interposed.
Threads are formed at the inlet 3 and the outlet 4 for connecting to the pipe. An annular groove is formed so as to surround the valve opening formed in the inlet side member 1, and the valve seat 5 is fitted into the groove.

The inner surface of the outlet member 2 is finished into a three-step cylindrical surface whose diameter gradually decreases toward the outlet 4. The cylindrical surface 6 closest to the inlet member 1 serves as a guide surface for the disc-shaped valve body 7, and an annular step portion 8 between the cylindrical surface 6 and the next cylindrical surface 8 is formed.
Has a function of preventing the excessive compression of the coil spring 9 by limiting the moving range of the valve body by hitting the outer peripheral edge of the valve body 7. A spring bearing 10 abuts on the annular step between the intermediate cylindrical surface and the cylindrical surface closest to the outlet 4.

The valve body 7 is disk-shaped and has a plurality of protrusions 11 on its outer circumference. The outer ends of the projections 11 are all located on concentric circles, and the diameter of the concentric circles is made slightly smaller than the guide surface 6 of the valve casing so that it can be slidably contacted with the guide surfaces. The spring receiver 10 is formed by pressing a thin plate, and a hole is formed in the center and a plurality of holes are formed around the hole. The edge of the central hole is bent toward the entrance. Coil spring 9 by fitting both ends into the bent corner and the annular groove formed on the back surface of valve body 7.
To place.

An annular groove is formed at the inner end of the inlet side member 1 on the outer periphery of the valve seat 5, and a coil-shaped shape memory alloy 12 as a temperature responsive member is arranged between this groove and the front surface of the valve body 7. . The shape memory alloy 12 deforms according to the temperature of the fluid. The deformation force of the shape memory alloy 12 at a low temperature is formed to be slightly stronger than the own weight of the disc-shaped valve body 7 and the elastic force of the coil spring 9. Figure 1
Indicates that the fluid temperature is below a predetermined temperature, the shape memory alloy 12 undergoes a martensitic transformation from the matrix phase to the martensite phase,
It has a long shape that has been stretched and memorized, and urges the valve body 7 in the valve opening direction against the urging force of the coil spring 9.

When the fluid temperature rises above a certain level, the shape memory alloy 12 undergoes a reverse transformation from the martensite phase to the matrix phase and becomes a short shape that has been contracted and memorized. It is no longer involved in the movement of body 7. If the fluid pressure at the inlet 3 is higher than that at the outlet 4, the valve body 7 compresses the coil spring 9 to displace it toward the outlet side, and opens the valve. When the fluid pressure at the outlet 4 becomes higher than that at the inlet 3, the valve body 7 is displaced toward the inlet side by the action of the fluid pressure and the coil spring 9 and comes into airtight contact with the valve seat 5.

[0012]

The present invention produces the following unique effects. As described above, according to the present invention, since the temperature responsive member opens the valve body greatly at low temperatures, low temperature water and air can be quickly discharged in a short time, and the startup time can be shortened.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a check valve of the present invention.

[Explanation of symbols]

 3 inlet 4 outlet 5 valve seat 7 disk-shaped valve body 9 coil spring 12 shape memory alloy

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[Procedure amendment]

[Submission date] May 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012]

The present invention produces the following unique effects. As described above, according to the present invention, since the temperature responsive member opens the valve body greatly at low temperatures, low temperature water and air can be quickly discharged in a short time, and the startup time can be shortened.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a check valve of the present invention.

[Explanation of symbols] 3 inlet 4 outlet 5 valve seat 7 disc-shaped valve body 9 coil spring 12 shape memory alloy

Claims (1)

[Claims] 1. An inlet and an outlet are formed by a valve casing, a valve seat is provided between the inlet and the outlet, a valve element is arranged on the outlet side of the valve seat, and a flow from the inlet to the outlet is allowed and vice versa. A non-return valve that stops a directional flow, provided with a temperature responsive member that urges the valve body in the opening direction at low temperatures.