SELF-CONTROL VALVE AND METHOD FOR LEAKING REDUCED-PRESSURE CHAMBER

摘要

PURPOSE:To reduce the time for the pressure in a reduced-pressure chamber to reach the atmospheric pressure and to prevent the suspension of dust in the reduced-pressure chamber by using a valve provided with a valve disk for controlling the inflow of a gas into the reduced-pressure chamber and a means for self-controlling the opening of the valve disk. CONSTITUTION:The valve disk 2 for controlling the inflow of the gas and a spring 5 for self-controlling the opening of the valve disk 2 are provided in the valve 11 for introducing the gas into the reduced-pressure chamber 10. Namely, when the gas is introduced into the reduced-pressure chamber 10, a three-way valve 9 is firstly energized and operated to introduce driving air into the part under a piston 4 not contg. the spring 5 of a cylinder 3 through a needle valve 7. The pressure of the driving air is gradually increased to push up the piston 4. The valve disk 2 connected to the piston 4 is also pushed up by the action of the piston 4, and separated from the valve seat 1 to form a gap in between. As a result, the gas can be smoothly introduced into the reduced-pressure chamber 10.