Mikroventilanordnung, insbesondere fuer pneumatische Steuerungen

The invention relates to a valve arrangement, in particular for use in pneumatic controls. Since pneumatically activated actuators have a certain leakage rate, the control valve (pilot valve) must remain in permanently open state in order to maintain the actuator in the open position. This requires high holding forces. The valve arrangement according to the invention, however, consumes energy only for the switchover process from one state to the other and can maintain the selected state without the use of any energy. This is achieved by means of an inlet and an outlet valve, whereby at least the inlet valve is a microvalve which has an idle position in addition to the open and the closed positions. In the idle position, there is a gap between the closing element and the valve seat of the microvalve, said gap being so dimensioned that the leakage rate of the actuator is compensated by the gas flowing through the gap. No energy is consumed in the idle position assumed by the valve when n o external forces are acting on it. In a special design, the valve closes automatically when a defined pressure difference exists