VACUUM PRESSURE CONTROLLER

Japanese Patent JP3777311

B2

PROBLEM TO BE SOLVED: To provide a vacuum pressure controller which can accurately hold low vacuum pressure close to atmospheric pressure. SOLUTION: This vacuum pressure controller has a vacuum proportional opening/closing valve 18 which varies vacuum pressure in a vacuum container 11 by varying an opening degree on piping connecting the vacuum container 11 with a vacuum pump 19 and a pressure sensor 17 which measures the vacuum pressure in the vacuum container 11 and controls the opening degree of the vacuum proportional opening/closing valve 18 according to the output of the pressure sensor 17; and (a) the vacuum proportional opening/closing valve 18 has a valve element having a horizontal valve seat part 36a and an O ring 35 which abuts against and separates from the horizontal valve seat part 36a, and (b) the vacuum pressure controller controls the pressure in the vacuum container 11 by varies the elastic deformation quantity of the O ring 35 according to the output of the pressure sensor 17 and then varying the quantity of a leak from the O ring 35.