| 摘要 |
PURPOSE:To prevent sticking of solder to the inside circumferential surface of a metallic pipe and to prevent formation of a flash at the end of the pipe by dipping the end of the metallic pipe into molten solder while supplying low-pressure air to the inside of the metallic pipe and pulling upward the pipe from the molten solder then passing compressed air into the pipe and blowing off the air from the end. CONSTITUTION:A copper pipe 1 is connected via a joint 12, a valve 8, etc. to an air compressor 11 and a bypass line 17 provided with a reducing valve 14, a flow rate control valve 15, a valve 16, etc. is provided in parallel with the valve 8. The end of the pipe 1 is dipped into the molten solder in a bath vessel 4 provided with a heater 3, the oscillating diaphragm 6 of an ultrasonic oscillator 5, etc. while the compressed air from the compressor 11 with the valve 8 held closed is reduced in pressure by the line 17 and is supplied as low-pressure air to the inside of the pipe 1. The solder is thus plated on the outside circumferential surface of the pipe 1 without sticking the solder to the inside circumferential surface thereof. After the pipe 1 is pulled up, the valve 8 is opened to supply directly the compressed air to the inside of the pipe 1 and to blow off the air from the end of the pipe, thus blowing away the sagging solder and preventing the solder from flashing. |
