JPH0369892A - Heating and heating tool for shape-memory alloy - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heating method and a heating tool for a heat-shrinkable shape memory alloy joint used for connecting pipes.

[Conventional technology]

The following method is generally used as a heating method for a joint in which a heat-shrinkable shape memory alloy joint is placed over a pipe to be connected, and the joint is heat-shrinked to connect the pipe to be connected.

(1) A method of heating by Joule heating by directly pressing an electrode against the joint and passing an electric current through it.

(2) Method of directly heating the joint with a burner flame.

Other methods were tried, but the heat dissipated from the connected pipes was large, and sufficient heating could not be achieved. In particular, in heat-shrinkable shape memory alloy joints, if the temperature is not raised to the required temperature as quickly as possible, the shrinkage ff1 (the amount of return to the memorized shape) may become small. Furthermore, in order to reduce heat dissipation from the connected pipes, it is necessary to raise the temperature quickly.

On the other hand, if the joint is heated too much, the epoxy adhesive applied to the inner surface of the joint to ensure airtightness will no longer function. For this reason, it was necessary to apply temperature-indicating paint to the joints and visually monitor them to ensure that excessive heating did not occur.

[Problem to be solved by the invention]

The method of applying current by directly pressing an electrode to the joint requires preparing a low-voltage, high-current power source as the heating tool, and then passing a large current between the power source (transformer) and the heating tool (7tt pole). Workability is poor because it requires a thick power cable. Furthermore, in the method of heating the joint with a banner flame, since flame is used, there is a very high risk of fire, and temperature control is difficult and requires skill.

[Means to solve the problem]

In view of this, as a result of various studies, the present invention has developed a heating method and a heating tool for shape memory alloy joints that allow the connection of pipes to be connected using heat-shrinkable shape memory alloy joints to be completed as quickly as possible, and that do not overheat the joints more than necessary. It is something.

That is, the heating method of the present invention is a heating method for a joint in which a heat-shrinkable shape memory alloy joint is placed over a to-be-connected vibrator, and the joint is heated and shrunk to connect the to-be-connected pipe. , an upper and lower split jig with a heating heater installed inside is provided opposite the grip part of the scissor-like handle, and the grip part is closed and the joint is gripped with a heat conductive compound between the split jigs. This is characterized by heating the joint by heating the joint, and heat conductive silicone grease or silicone rubber is used as the heat conductive compound.

In addition, the heating tool of the present invention is a heating tool for a joint that connects a pipe to be connected by placing a heat-shrinkable shape memory alloy joint over the pipe to be connected, and forming a concave groove for gripping the joint on the inner surface, The device is characterized in that a vertically divided jig incorporating a heating heater and a temperature sensor is provided on the opposite side of the grip of the scissor-like handle.

[For production]

As described above, the present invention forms a joint gripping groove on the inner surface,
The joint is gripped and heated using a top and bottom split jig with a built-in heating element.The size of the split jig is kept to the minimum necessary, and a heat conductive compound, such as silicone, is used between the jig and the joint. By filling the compound or silicone rubber to improve heat transfer from the jig to the joint, heating can be performed as quickly as possible even if heating starts from room temperature.

By minimizing the size of the dividing jig and the heater in this way, it becomes possible to use electric wires of normal thickness as power lines for obtaining the necessary power, and the jig becomes easy to handle. In addition, by providing the split jig on the opposite side of the grip of the scissor-like handle, it is possible to open the grip and set the joint so that it is gripped from the side of the joint.
By bringing the grip portion closer to the heating inner ring, the dividing jig can be brought closer to each other, thereby preventing the generation of gaps due to contraction of the joint.

Furthermore, by providing the divided jig with a temperature sensor for controlling the temperature of the jig body and connecting it to a control box, it is possible to prevent the jig body from overheating more than necessary. In order to improve heat transfer from the heater to the jig, it is preferable to assemble the jig so that there is no gap between the heater and the jig body, and fill the jig with a heat conductive compound as necessary. In addition, silicone compound or silicone rubber was filled between the joint and the jig as a heat conductive compound, but from the standpoint of removal after heating, it has appropriate heat conductivity and does not have an air layer that can cause heat transfer problems. It is desirable to use silicone rubber that can be removed.

〔Example) Examples of the present invention will be described below.

A heat-shrinkable shape memory alloy joint was broken into a pipe to be connected, and the pipes were connected by heating and shrinking the joint using a dividing jig shown in FIGS. 1(-r) and (b).

As shown in the figure, the splitting jig has a scissor-like grip (
3), on the opposite side of f3') and the shaft (5), there is a jig (7) that opens left and right and has a gripping groove formed on its inner surface;
A cartridge heater (1) and a temperature sensor (2) are installed parallel to the joint gripping part (6) in which a groove for gripping is formed in the jig (?). Part (31
, (3') to the left and right, the jig (7), (
7M was opened from side to side, heat conductive silicone rubber (4) was placed between it and the joint (not shown) placed over the connecting pipe, and the joint was grasped from the side.

In this way, current is applied to the cartridge heater (1) while closing the grips (3), (3'), and the jigs (71, (3') are closed.
7'), the joint was heat-shrinked and the pipe to be connected was connected. The size of the jigs (7) and (7') is the minimum necessary, and in order to improve the heat transfer from the heater (1) to the jigs (7) and (7'), 711?'
) and filled with heat conductive compound as necessary. In addition, in order to control the temperature of the jigs (71, (7')), the temperature sensor (2) is connected to the control box with a lead wire (not shown), and a 0N10FF
Power was supplied to the heater (1) through the relay using an electric wire of normal thickness that was easier to handle than the direct commercial power supply.

In this way, 3/8' to the joint and 60Q to the heater capacity.
The heater power was controlled using a temperature sensor to prevent the jig from overheating to over 300°C. As a result, not only was the jig easy to handle, but the one that used a heat conductive compound between the jig and the joint was able to be heated to 230°C with 19 or more pieces.

On the other hand, when a heat conductive compound is not used between the jig and the joint, the temperature rise above 180℃ is extremely slow, and even when considering the adhesion between the jig and the joint, the temperature rises from room temperature to 230℃.
It took more than 3 minutes to heat up to ℃. The two gripping parts were brought close to each other so as to constantly grip the joint during heating, thereby preventing the generation of a gap due to contraction of the joint.

〔Effect of the invention〕

According to the present invention, when connecting pipes using a heat-shrinkable shape memory alloy joint, not only is it easy to handle, but the joint is not heated more than necessary, and the connection work can be completed in a short time. It has remarkable industrial effects.

[Brief explanation of drawings]

FIGS. 1A and 1B show an embodiment of the heating tool of the present invention, in which FIG. 1A is a side view and FIG. 1B is a front view. Cartridge heater temperature sensor (3') grip part heat conductive compound shaft joint grip part (7') jig Fig. 1

Claims (3)

[Claims] (1) In a heating method for a joint in which a heat-shrinkable shape memory alloy joint is placed over a pipe to be connected, and the joint is heat-shrinked to connect the pipe to be connected, a groove for gripping the joint is formed on the inner surface,
A top and bottom split jig with a heating heater installed inside is provided opposite the grip of the scissor-like handle, and the grip is closed to grip the joint with a heat conductive compound interposed between the split jigs. A method for heating a shape memory alloy joint, characterized by heating the joint. (2) The method for heating a shape memory alloy joint according to claim (1), wherein thermally conductive silicone grease or silicone rubber is used as the thermally conductive compound. (3) In a heating tool for a joint that connects a pipe by placing a heat-shrinkable shape memory alloy joint over a pipe to be connected and shrinking the joint by heating, a groove for gripping the joint is formed on the inner surface and a groove for heating is formed inside. A heating tool for a shape memory alloy joint, characterized in that a vertically divided jig incorporating a heater and a temperature sensor is provided facing the opposite side of the grip of a scissor-like handle.