Auxiliary adjuster for pneumatic regulating value - has at least one pressure chamber for setting working piston so that compressed air needed is taken from main supply

摘要

The compressed air is esp. supplied across a setting sensing unit and a regulator. The compressed air needed for setting the working piston (7) of the drive (5) is led over a first input of an OR element (16), pref. in the form of a double working non-return valve, the output of which is connected to the pressure chamber (7.1;7.2) of the drive (5), and the second input to a further compressed air supply via a supply line (13). A first magnetic valve (14) is connected in the supply line (13), the coil (14.1) of which lies in a holding current circuit with at least one off switch (17.1;22.1). Upon switching off of one switch, the coil (14.1) of the magnetic valve (14) is deenergised and changes over. A second magnetic valve (15) has its input connected to the control line (4.2;4.3) of the setting transmitter and regulator (4). Its outputs are connected to one of the drive lines of the pneumatic drive as well to a pressure release. The coil (15.1) of the second magnetic valve lies in a holding current circuit with at least one off switch and is changed over in the same way as the valve (14). The venting of the magnetic valves (14,15) is carried out via silencers (19.1;19.2). ADVANTAGE - Setting of pneumatic or hydraulic servo valves with required backup achieved with one valve and drive.