EVACUATION SPEED CONTROL METHOD BY MOTOR-DRIVEN VACUUM VALVE, EVACUATION SPEED CONTROL SYSTEM BY MOTOR-DRIVEN VACUUM VALVE, VALVE OPENING DEGREE SET POINT DECISION METHOD OF MOTOR-DRIVEN VACUUM VALVE USED FOR EVACUATION SPEED CONTROL, AND EVACUATION SPEED DECISION PROGRAM USED FOR EVACUATION SPEED CONTROL

摘要

PROBLEM TO BE SOLVED: To provide an evacuation speed control method by a motor-driven vacuum valve which can easily and inexpensively set a set point for switching a valve opening degree of the motor-driven vacuum valve so as to bring the pressure in a chamber close to a target pressure lowering gradient.;SOLUTION: The evacuation speed control method performs stepwise control of an opening degree of a motor-driven vacuum valve 21 according to an equal ratio multiple number, makes a vacuum pump 13 evacuate from a viscous flow domain for each opening degree, after measuring vacuum pressure in a chamber by a pressure sensor 15 and actually measuring pressure lowering curves Y1, Y2, Y3, Y4, temporally shifts the pressure lowering curves Y1, Y2, Y3, Y4 so as to approximate to a target pressure lowering gradient X, decides mutual crossing points of the pressure lowering curves Y1, Y2, Y3, Y4 at set points P11, P12, P13 switching the valve opening degree of the motor-driven vacuum valve 21, after this, switches the valve opening degree of the motor-driven vacuum valve 21 on the basis of the set points P11, P12, P13 to control the evacuation speed in the viscous flow domain.;COPYRIGHT: (C)2011,JPO&INPIT