JPS649121A - Vacuum contact packing method and apparatus - Google Patents

Abstract

PURPOSE:To reduce the vacuum degassing time of the whole of a process, by interposing a pressure control valve to the second branch line for a lower chamber and allowing the atmosphere to flow in the lower chamber through a communication hole at the time of the inflow of the atmosphere and discharging a large amount of the air in the lower chamber from a valve hole at the time of vacuum degassing. CONSTITUTION:A pressure control valve 17 is automatically operated on the basis of the pressure difference between both upper and lower chambers 2, 3 and acts so as not to make the degassing time of the lower chamber 3 long. At the time of vacuum degassing, the air in the upper chamber 2 is sucked by a vacuum pump 11 but, since the lower chamber 3 is evacuated by the vacuum pump 11 through the communication hole 26 of the pressure control valve 17, the vacuum degassing treatment of the upper chamber 2 is performed more fast. An upper film 6 is pressed to a hot plate 4 on the basis of the pressure difference between both upper and lower chambers 2, 3 to be subjected to softening chambers 2, 3 to be subjected to softening treatment under heating. Next, a vacuum valve 16 is 3 closed and a blow valve 15 is opened to perform the 'atmosphere inflow' treatment of both upper and lower chambers 2, 3. The atmosphere flows in the lower chamber 3 through the communication hole 25 since the pressure control valve 17 is closed.