CONTROL DEVICE FOR A SAFETY VALVE

摘要

A control device includes a pressure-displacement transducer for triggering a control part for activating a safety valve of a pressure vessel. A space in the pressure-displacement transducer can be connected to a blow-off tank through a drainage line. A first embodiment includes a switchover valve device which is associated with the drainage line and connects the space to a take-off line instead of to the blow-off tank when the pressure in the blow-off tank is above a limiting pressure. A second embodiment includes a hydraulic compensating system which exerts a first force on the pressure-displacement transducer, from a pressure in the blow-off tank. That force counteracts a second force produced in the space by that pressure and in particular compensates for that force.