PURPOSE: To improve faults of the rubbing structure of a seal ring due to sliding resistance and wear of a valve body and also to smoothly open and close a main valve by small force without influence of fluctuations of pressure by eliminating the sliding portion of the valve body.
CONSTITUTION: In the closed valve condition of a main valve 21 and a sub valve 22, pressure in a sub valve chamber 27 becomes same pressure as first side pressure since the first side pressure is continuously introduced thereto via a bleed orifice 28. Driving means 14 is operated to start and drive a main valve 21, during the closed valve condition of the main valve yet, the sub chamber 22 is moved, and opened, by a predetermined stroke formed at an interval that a projection 25 provided at the driving shaft 23 of the driving means 14 is abutted to the main valve 21. The main valve 21 is started and moved with the sub valve 23 and is opened. Even if a diaphragm is damaged, pressure in the sub valve chamber 27 is made as the first side pressure due to the bleed orifice 28 so that the sub valve 22 is automatically closed by a return valve 30 to make no gas etc leak to a secondary side.
TSUMURA TAKASHI
INAGAKI HIROYUKI
| JPS5228813U | 1977-02-28 | |||
| JP46004947U | ||||
| JP63129781B | ||||
| JP61204084B | ||||
| JPH037911U | 1991-01-25 |