JPS595066B2 - How to connect pipes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for connecting two pipes having different diameters by dipping them into a molten brazing filler metal.

For example, when connecting the capillary tube of a refrigerator to the pipe on the refrigerant supply side of a cooler, insert the capillary tube, which is a small diameter pipe, to a specified depth into the cooler pipe, which is a large diameter pipe, and melt them in this state. The molten brazing material enters the cooler pipe by immersing it in the material, and then the molten brazing material is cooled and solidified to connect both pipes.

In this connection method, in order to obtain the desired mechanical strength and sealing performance against the progression of corrosion depth at the joint 5 of both pipes, a predetermined amount of penetration height of the brazing filler metal into the cooler pipe is required. The intrusion of the molten brazing material into the cooler pipe is a natural intrusion, and the air release inside the cooler pipe due to the intrusion of the molten brazing material is inhibited by the conduit resistance of the cooling pipe and capillary tube. Due to the viscosity of the molten filler metal, the penetration of the molten filler metal does not occur smoothly.
It was difficult to obtain a predetermined penetration height in a short period of time. 1
5 The present invention has been made in view of the above circumstances, and its purpose is to reduce the pressure inside the large-diameter pipe or pressurize the molten brazing material so that the brazing material enters the large-diameter pipe at a level higher than the molten liquid level. By heating the portion 20 of the large-diameter pipe near the molten liquid surface of the filler metal, the filler metal can quickly penetrate into the large-diameter pipe to a sufficient height. Provides a linking method.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a refrigerator cooler 25, which has a refrigerant supply side end of a refrigerant passage made of an aluminum pipe, that is, an inlet pipe 2, which is a large diameter pipe, directed downward, and a refrigerant outlet side of the refrigerant passage. The end portion, ie, the outlet pipe 3, is supported by a support device (not shown) in an upwardly oriented state. Reference numeral 4 denotes an intake cylinder 30, which is equipped with a piston and an electromagnetic solenoid inside, and is configured to suck a predetermined amount of air when the electromagnetic solenoid is energized, and its intake port is fitted into the outlet pipe 3 of the cooler 1. are combined.

5 is a 35-piece copper capillary pipe with a small diameter.
This is bent into a substantially U-shape and its tip end is connected to the inlet pipe 2.
The support device is supported and fixed to the support device while being inserted a predetermined amount into the lower end of the support device.

Reference numeral 6 denotes a solder bath which is heated by a heating means that does not move (not shown). Molten solder 7, which is a molten brazing material, is stored inside this bath. Although not shown, ultrasonic vibrations are applied to this molten solder 7. A vibration generator is provided to improve the penetration property.

Reference numeral 8 denotes a heating device, such as a heating coil for high-frequency induction heating (shown only in FIG. 2), which is arranged so as to surround a portion of the inlet pipe 2 near the molten liquid surface 7a of the molten brazing filler metal 7. .

To connect both pipes 2 and 5, first insert the capillary tube 5 into the inlet pipe 2 so that its upper end is higher than the heating coil 8, and then is slightly immersed in molten solder 7.

After that, while the heating coil 8 is energized to heat the inlet pipe 2, the electromagnetic solenoid of the intake cylinder 4 is energized,
When the air in the refrigerant passage of the cooler 1 is sucked, the pressure in the refrigerant passage of the cooler 1 and in turn the inlet pipe 2 is reduced. Therefore, the molten solder 7 is sucked up to a higher level than the liquid level, and the heating coil 8 causes the molten solder 7 to reach the molten liquid level 7a in the inlet pipe 2.
Since the vicinity is heated, the sucked up molten solder 7 does not cool and solidify as soon as it rises from the liquid level 7a, and instantly rises to a predetermined height determined by the amount of pressure reduction by the intake cylinder 4. Thereafter, the inlet pipe 2 and capillary tube 5 are pulled up from the molten solder 7 and solidified, and finally, for example, an anti-rust paint is applied to the solder-attached portion to form an anti-rust layer 9 (see FIG. 3). According to the embodiment described above, the pressure inside the inlet pipe 2 is reduced and the molten solder 7
is forcibly entered into the pipe 2,
With the conventional method of simply dipping and allowing the molten solder to penetrate naturally, it took a relatively long time for the molten solder to penetrate, but it is now possible to penetrate the molten solder extremely quickly, reducing work time. Productivity can be improved. In addition, in the conventional method of allowing natural penetration, the penetration height of molten solder is only about 40 to 60% of the immersion depth due to the resistance caused by air discharge from the cooler and the viscosity of the molten solder. Therefore, in order to obtain a predetermined penetration height, the inlet pipe had to be immersed sufficiently deep into the molten solder, but according to this embodiment, the molten solder 7 is sucked up and penetrated into the inlet pipe 2. In addition, since the part of the inlet pipe 2 near the liquid surface 7a of the molten solder 7 is heated by the heating coil 8, the inlet pipe 2
The molten solder 7 that has entered the interior can be sucked up to a sufficient penetration height without being cooled and solidified midway. Therefore, the immersion depth of the inlet pipe 2 into the molten solder 7 can be reduced, so the solder tank 6 can be made shallow and the amount of molten solder 7 stored can be reduced to a small amount. It is possible to reduce the required amount of heating and achieve significant power savings. In addition, since the immersion depth of the inlet pipe 2 can be made shallow in this way, the amount of solder adhering to the outer surfaces of the inlet pipe 2 and the capillary tube 5 can be reduced, thereby forming a rust preventive layer 9 on the solder adhesion parts. Even in the case of coating, it is possible to reduce the amount of anticorrosion paint used and reduce manufacturing costs. Incidentally, in the above embodiment, the case where the present invention is applied to the connection between the pipe of the cooler of the refrigerator and the capillary tube has been described, but the present invention is not limited to this and can be applied to all cases where two pipes are connected, for example. Even in the case of pipes of the same diameter, the connecting end of one pipe is expanded by flaring to create a larger diameter pipe, and the connecting end of the other pipe, which is a smaller diameter pipe, is inserted into the expanded part and joined. It can also be applied in some cases.

Further, in the above embodiment, the pressure is reduced on the inlet pipe side of the cooler, which is a large diameter pipe, but the invention is not limited to this, and the inlet pipe side may be communicated with the atmosphere and the molten brazing material liquid surface side may be pressurized. . As described above, the present invention reduces the pressure inside the large-diameter pipe or pressurizes the molten brazing filler metal to infiltrate the brazing filler metal into the large-diameter pipe to a level higher than the molten liquid level, and The feature is that the part of the brazing filler metal near the molten liquid surface is heated, and as a result, even if the depth of immersion of the large diameter pipe into the molten brazing filler metal is shallow, the melting does not flow into the large diameter pipe. The brazing filler metal can be penetrated to a sufficient height and quickly, and the power consumption of the solder bath can be reduced, as well as the amount of solder adhering to the outer surface of each pipe can be reduced. play.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a longitudinal sectional view of the whole, Fig. 2 is an enlarged sectional view showing the state of immersion of the connecting portion of both pipes in molten brazing filler metal, and Fig. 3 is a rust prevention layer. This is an enlarged cross-sectional view showing the joint state of both pipes covered with ), 8 is a heating coil.

Claims (1)

[Scope of Claims] 1. With the connecting end of the small diameter pipe inserted into the connecting end of the large diameter pipe, the connecting end of the small diameter pipe is immersed in molten brazing filler metal to cause the brazing filler metal to enter the large diameter pipe, thereby forming both ends. In a device that connects pipes, the pressure inside the large-diameter pipe is reduced or the molten brazing material is pressurized to allow the brazing material to enter the large-diameter pipe to a level higher than the molten liquid level, and the brazing material in the large-diameter pipe is A method for connecting pipes, characterized in that a portion near the molten liquid surface of the pipe is heated. 2. The method for connecting pipes according to claim 1, wherein after connecting both pipes, the portion to which the brazing material is attached is coated with a rust-preventing layer.