| 摘要 |
PURPOSE:To provide a gas proportional control valve with a closing function capable of increasing a closing function of the valve without giving influences to the gas by combining a diaphragm valve and an electromagnetic mechanism. CONSTITUTION:An electromagnetic mechanism 20 is composed of a cover member 21 coupled to a main body 10 so that it is provided on the back pressure side of a diaphragm 2, that is, on the side of an upper chamber 4; a bobbin case 22 in the member 21; and an electromagnetic coil 23 wound around the bobbin case 22; a yoke member 25 inserted and fixed into a vertical hole 24 at the central part of the bobbin case; and a plunger 26 vertically slidable so that it opposes the lower end surface of the yoke member 25. When a current value is varied in a state where the plunger 26 is adsorbed to the yoke member 25, the magnetic force varies to strong and weak and the repulsive force against a magnet body 5 also varies.Hence, the opening degree of the valve varies in accordance with this. Accordingly, when the current is decreased to a value at which the plunger can be separated from the yoke member, the flow quantity of the gas can be controlled to a small value. When the current is increased, the master valve opens largely and the flow quantity of the gas can be controlled largely. |
