Isolating device for calibrated safety valve

摘要

Isolating device for positioning in a circuit upstream of the safety valve, wherein it comprises a valve member which can sealingly bear on a valve seat formed in the said circuit, neutralization means which normally maintain the valve member remote from its seat, said means being actuatable to bring the valve member in sealing engagement with its seat when it is necessary to isolate the safety valve and calibration means acting on the valve member when it is sealingly engaged with its seat to enable it to move away from the latter when the pressure upstream of the isolating device exceeds a determined value.