US Patent 7343845 Fluid operated position regulator

A fluid operated position regulator comprises a servo means, arranged in a regulator housing and by which a supply connection, a venting connection and a power connection can be placed in circuit in an adjustable manner. To predetermine or set its position the servo means possesses two mutually oppositely orientated fluid actuating faces of equal size, which respectively delimit a control chamber. The two control chambers are connected by way of an intermediately placed choke means with a common control pressure connection. Downstream from the two choke means each control chamber is connected with a venting connection. A control valve means can control the two venting connections and in particular simultaneously close them.