Abstract: A vacuum pressure control apparatus includes a vacuum proportional opening and closing valve 18 which is disposed on a pipe connecting a vacuum chamber 11 and a vacuum pump 19 and changes its opening to control the vacuum pressure in the vacuum chamber 11, and a pressure sensor 17 which measures the current vacuum pressure in the chamber 11. The vacuum proportional opening and closing valve 18 has a valve seat 36 and a valve member 33 provided with an O-ring 35 which is made contact with or separate from the valve seat 36. The vacuum pressure control apparatus configured as above controls the pressure in the chamber 11 by changing an elastic deformation amount of the O-ring 35 which is in contact with the valve seat 36 and thereby changing the flow quantity of gas leaking between the valve seat 36 and the O-ring 35.

Abstract: In a vacuum pressure control system, the vacuum pressure in a reaction chamber 10 is measured by vacuum pressure sensors 14 and 15 (S22), the measured value is changed at a set vacuum pressure changing speed commanded from the exterior or determined and stored in advance in a controller of the system (S24). The changed value is sequentially generated as an internal command. In response to the sequentially generated internal commands, a desired value of the feedback control is changed in sequence (S26), so that the feedback control is executed as follow-up control (S27). Accordingly, the vacuum pressure in the reaction chamber 10 can be uniformly changed to a desired vacuum at a set vacuum pressure changing speed.

Abstract: In a vacuum pressure control system constituted of a vacuum vessel, a vacuum pump sucking gas in the vacuum vessel, a vacuum proportional opening and closing valve disposed on a pipe connecting the vacuum vessel and the vacuum pump, the vacuum proportional opening and closing valve changing its opening to change the vacuum pressure in the vacuum vessel, a pressure sensor to measure the vacuum pressure in the vacuum vessel and a vacuum pressure control device to control the opening of the vacuum proportional opening and closing valve based on the output of the pressure sensor, the vacuum proportional opening and closing valve is provided with a valve seat, a valve member with a tapered surface in its outer periphery and a pilot valve, the valve member being movable along a center line of the valve seat to change a clearance area between the valve seat and the tapered surface, and the vacuum pressure control device controls a servo valve to change the pressure of air to be supplied to the pilot valve based on t

Abstract: In a vacuum pressure control system constituted of a vacuum vessel, a vacuum pump sucking gas in the vacuum vessel, a vacuum proportional opening and closing valve disposed on a pipe connecting the vacuum vessel and the vacuum pump, the vacuum proportional opening and closing valve changing its opening to change the vacuum pressure in the vacuum vessel, a pressure sensor to measure the vacuum pressure in the vacuum vessel and a vacuum pressure control device to control the opening of the vacuum proportional opening and closing valve based on the output of the pressure sensor, the vacuum proportional opening and closing valve is provided with a valve seat, a valve member with a tapered surface in its outer periphery and a pilot valve, the valve member being movable along a center line of the valve seat to change a clearance area between the valve seat and the tapered surface, and the vacuum pressure control device controls a servo valve to change the pressure of air to be supplied to the pilot valve based on t