Valve unit for an electrostatic coating installation

Valve unit for an electrostatic installation for the series coating of workpieces one remotely controlled switching valve whose valve element (1) mobile is displaceable between two switching positions and in one of the switching positions opens the way for a medium flowing through the valve while the valve is closed when the valve member (1) is in its other switching position, in particular for an atomiser which during operation is subjected to high voltage, It is provided for the interrogation of the switching position of the valve and for generating a binary signal corresponding interrogation device optoelectronic sensor with at least one waveguide (20, 21) in a construction element (10) it is displaceable with the valve member (1) or forming a part of the valve member, characterized by an electronic control device determines whether the binary signal appears in the predetermined time after the generation of a signal interval time switch control valve and because, otherwise, an alarm signal is generated.