JPH0325485Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention includes a temperature-sensitive element that is heated and cooled by a controlled fluid and operates a valve means according to the temperature of the fluid.
The present invention relates to a temperature-responsive valve that controls fluid passage through the valve depending on the temperature of a controlled fluid. This temperature-responsive valve is used as a steam trap that automatically removes condensate generated in a steam system, and as an antifreeze valve that opens just before water pipes freeze to prevent water leakage.

Recently, the use of shape memory alloys as temperature-sensitive elements has been actively developed. Shape memory alloys include alloys of titanium and nickel, or alloys of copper, aluminum, and nickel.
When heated or cooled and subjected to temperature changes, it undergoes a reversible martensitic transformation between the parent phase and the martensitic phase, changing its shape. Even if this alloy is given a certain shape in the martensitic phase, when the temperature rises and the alloy returns to the parent phase, it returns to the shape previously memorized in the parent phase. Therefore, this shape memory alloy can be used as a driving element of a valve in place of a conventional temperature-sensitive element such as a bimetal.

BACKGROUND ART Japanese Patent Application Laid-Open No. 150680/1983 discloses a temperature-responsive valve using a shape memory alloy. A shape memory alloy formed into a coil shape and a return spring are combined with a valve body. When the temperature of the controlled fluid rises, the shape memory alloy compresses the return spring and expands to move the valve body closer to the valve port and close it. When the temperature does not drop, the shape memory alloy is compressed by the return spring and contracts, causing the valve body to move away from the valve port and open the valve.

In this case, when the valve body comes into contact with the valve seat forming the valve port, the shape memory alloy has not completed its transformation and reached the parent phase, but is in the middle of transformation. This is because no further growth can be expected after the completion of transformation, making valve closing uncertain. For this reason, if the valve is not completely closed due to the influence of dust or scale, and the fluid leaks and becomes overheated, the shape memory alloy will be subjected to extremely strong external forces during the transformation process, causing the memory shape to change. Change. Once the memorized shape changes, that is, changes to a shape that makes it impossible to close the valve completely, a vicious cycle occurs and it becomes increasingly difficult to close the valve completely. Therefore, in order not to shorten the life of a valve using a shape memory alloy, it is necessary to prevent overheating and incomplete valve closing from occurring.

Means for Solving the Problems The technical means of the present invention taken to solve the above problems are as follows: (a) The main valve seat and the auxiliary valve are placed on the outside of the main valve seat surrounding the valve port on the downstream side of the valve port. (b) A main valve body having a valve surface to be in contact with the main valve seat is slidably installed in an airtight manner into an auxiliary valve body having an annular valve surface to be in contact with the auxiliary valve seat; C. A spring is installed between the main valve body and the auxiliary valve body to bias it toward the valve seat, and d. The main valve body is biased by the spring so that its valve surface is closer to the valve seat than the auxiliary valve body by a predetermined amount. A stopper is provided on the auxiliary valve body so that it can protrude, and a shape memory alloy is attached so that the auxiliary valve body moves toward the valve seat when the temperature increases.

Effect The operation of the above technical means is as follows.

Since the main valve body and the auxiliary valve body are located on the downstream side with respect to the valve port, they receive fluid pressure in a direction in which they are pulled away from their respective valve seats. When the temperature of the controlled fluid is low, the main valve body and the auxiliary valve body are separated from their respective valve seats by the action of this fluid pressure, and the valve ports are opened.
The upstream fluid passes through the valve port and flows around the shape memory alloy.

When the temperature of the controlled fluid increases, the shape memory alloy undergoes transformation, displacing the auxiliary valve body toward the valve seat. Since the main valve element is biased toward the valve seat by a spring relative to the auxiliary valve element, it can be brought close to the main valve seat together with the auxiliary valve element. Then, when a predetermined temperature at which the valve should be closed is reached, the valve surface of the main valve body comes into contact with the main valve seat. At this time, the valve surface of the auxiliary valve body does not yet come into contact with the auxiliary valve seat. Moreover, the shape memory alloy is in the process of transformation.

At this time, when the valve surface of the main valve body contacts the main valve seat,
If complete valve closure is achieved and no leakage occurs, the shape memory alloy located downstream of the valve port will not be heated above this temperature.

If a leak occurs due to dirt or scale getting caught between the main valve seat and the valve surface of the main valve body, the leaked fluid will heat the shape memory alloy to an even higher temperature. Then,
The auxiliary valve body is further displaced and finally comes into contact with the auxiliary valve seat, stopping fluid leaking from between the main valve body and the main valve seat. At this time, the shape memory alloy is still in the process of transformation, but it is no longer heated and exposed to abnormally high temperatures.

Effect of invention The present invention produces the following specific effects.

In this invention, an auxiliary valve seat is provided downstream of the main valve seat, so that the auxiliary valve element contacts the auxiliary valve seat after the main valve element contacts the main valve seat, so that dust and scale can be removed from the auxiliary valve seat. The probability of being caught between the seat and the auxiliary valve body is extremely small, and fluid leakage can be almost completely prevented.

Although it has been conventional practice to provide a spring to absorb excessive transformation of the shape memory alloy in the event of fluid leakage, this technique does not prevent the shape memory alloy from being heated to abnormally high temperatures. In the present invention, fluid leakage is prevented and the shape memory alloy is not heated, so the shape memory effect lasts for a long time.

Embodiment An embodiment illustrating a specific example of the above technical means will be described (see FIGS. 1 to 3).

The casing members 1 and 2 are screwed together to form an inlet 3, a valve chamber 4, and an outlet 5. A valve seat member 6 is screwed into a hole in the casing member 1 that communicates with the valve chamber 4 . A valve port 7 is opened in the center of the valve seat member 6, and a main valve seat 8 is formed surrounding the valve port 7 at the end on the side of the valve chamber 4, and an auxiliary valve seat 9 is formed on the outer end surface thereof. The casing member 2 has a hole 10 formed on its central axis, and a passage 11 that penetrates the valve chamber 4 and communicates with the outlet 5 on the outside thereof.

An auxiliary valve body 12 having a cylindrical shape and having a plurality of protrusions formed on the outside is disposed within the hole 10 of the casing member 2. A main valve body 13 is securely and slidably attached to the auxiliary valve body 12 with an O-ring 14 attached to its outer periphery. A conical valve head that contacts the main valve seat 8 to open and close the valve port 7 is formed at the tip of the main valve body 13. The other end of the main valve body 13 is formed to have a small diameter, and a spring 15 is arranged around it between it and a snap ring 16 attached to the auxiliary valve body 12. Therefore,
The main valve body 13 is urged in the direction of the valve port 7 by a spring 15, and a stopper portion 17 provided on the auxiliary valve body 12
It is locked in.

A hole is made perpendicularly to the hole 10 of the casing member 1 and an adjusting screw 18 is screwed therein. The tip of the adjusting screw abuts a ball 19 disposed within the hole 10. A shape memory alloy 20 is placed between the protrusion of the auxiliary valve body 12 and the ball 19. Therefore, by rotating the adjustment screw 18 and moving the position of the ball 19 from side to side, the distance between the auxiliary valve body 12, which is moved by the shape memory alloy 20, and the valve seat member 6 can be adjusted, and the opening/closing valve temperature can be adjusted. Can be adjusted. When the shape memory alloy 20 is cooled to a predetermined temperature or lower, it undergoes a thermoelastic transformation from the parent phase to a martensitic phase, and when it is heated to a predetermined temperature or higher, it undergoes the reverse transformation. It is made to elongate in the matrix phase and contract in the martensitic phase. The hole 10 of the casing member 2 and the passage 11 are connected through a communication hole 21.

Shape memory alloy 2 when the temperature of the controlled fluid is low
0 is contracted. The main valve body 13 and the auxiliary valve body 12 are moved away from the valve seat member 6 to open the valve port 7 under the action of fluid pressure from the inlet port 3 . The fluid flows from the valve port 7 through the passage 11, the hole 10, the communication hole 21, the passage 11, and out the outlet 5 (see FIG. 1).

When the temperature of the controlled fluid increases, the shape memory alloy 2
0 expands, displacing the auxiliary valve body 12 in the direction of the valve seat member 6. Since the main valve body 13 is biased toward the valve seat member 6 by the spring 15 with respect to the auxiliary valve body 12, the main valve body 13 is displaced together with the auxiliary valve body 12, and when a predetermined temperature is reached, the main valve body 13 is moved toward the valve seat member 6. The valve port 7 is closed by contacting the main valve seat 8 of the member 6. At this time, the auxiliary valve body 12
is not in contact with the auxiliary valve seat 9 (see Figure 2).

In this state, when leakage occurs from the valve port 7 and the shape memory alloy 20 is further heated, the auxiliary valve body 12 is further displaced and comes into contact with the auxiliary valve seat 9 to prevent leakage (see FIG. 3).

The shape memory alloy 20 contracts when the ambient temperature decreases and returns to the state shown in FIG.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a temperature-responsive valve according to an embodiment of the present invention, when the fluid temperature is low. FIG. 2 is an enlarged view of the valve section when the fluid temperature rises.
FIG. 3 is an enlarged view of the valve portion when the fluid temperature further increases. 3: Inflow port, 4: Valve chamber, 5: Outflow port, 6: Valve seat member, 7: Valve port, 8: Main valve seat, 9: Auxiliary valve seat, 1
2: Auxiliary valve body, 13: Main valve body, 15: Spring, 1
7: Stopper part, 20: Shape memory alloy.

Claims (1)

[Scope of utility model registration request] A main valve seat surrounding the valve port and an auxiliary valve seat should be provided on the outside of the main valve seat on the downstream side of the valve port, and the main valve body, which has a valve surface that should be in contact with the main valve seat, should be in contact with the auxiliary valve seat. The auxiliary valve element has an annular valve surface and is slidably installed in an airtight manner, and a spring is installed between the auxiliary valve element and the auxiliary valve element to bias the main valve element toward the valve seat. A stopper is provided on the auxiliary valve body so that the valve surface can protrude toward the valve seat by a predetermined amount beyond the auxiliary valve body when energized, and a shape memory alloy is installed so that the auxiliary valve body is displaced toward the valve seat when the temperature increases. Temperature-responsive valve with attached.