Safety valve for tank of fluid under pressure such as LPG has spring pressure controlled by perforated screw inside valve housing

摘要

Valve consists of hollow housing (2) containing spring (7) which interacts at one end with stopper (9) equipped with base seal (13). Pressure of spring against stopper is controlled by perforated screw (8) which screws into housing. Valve pressure is balanced by second spring (12) or rod with shape memory effect which allows gases under excessive pressure to be released through ejectable cap (20). The second spring or rod has a stiffness which increases up to a predetermined threshold temperature level. the safety valve can be linked to an indicator on the vehicle dashboard to show when the valve is actuated.