| 摘要 |
PURPOSE:To simplify a sealing-off operation without requiring the treatment after a cooling medium being injected in the device by a method wherein after an exhaust pipe for sealing-off is connected to the cooling device in which a semiconductor rectifying device is housed and the device is exhausted inside to be injected with the cooling medium, a part of the exhaust pipe is welded. CONSTITUTION:The cooling device in which the semiconductor rectifying device is housed is formed by a Freon tank 1, a condenser 2 and a stack unit 5 in which a semiconductor rectifying element and fins are arranged in parallel, and the sealing- off exhaust pipe 3 made of copper, stainless steel and soft steel is connected to a part of the side wall of the cooler 2. Then, a vacuum pump 7 is connected to an end of the exhaust pipe 3 through a valve 10 and a Freon bomb 6 is connected through a valve 9. With the thus constructed device, the device is exhausted inside at first by the pump 7 and then, injected with the Freon liquid from the bomb 6. Thereafter, a tube reduced part 3a formed at the center of the tube 3 is applied an irradiation of laser rays 11a from a carbon-dioxide gas laser oscillating device 11 and cut down at the latter part thereof after being applied a seam welding. |
