RAPID CLOSING SAFETY RELIEF VALVE

摘要

A safety valve intended to limit the pressure of a fluid contained in a vessel to which the valve is connected by a nozzle closed off by a flap-valve pressed against its seat by a spring acting on a first side of the flap-valve. The valve has two operating states; either the flap-valve is closed when the fluid pressure in the vessel acting through the nozzle on the opposite or second side of the flap-valve is below a pre-determined value or the flap-valve is open allowing fluid from the vessel to escape via an escape chamber in the valve when the pressure in the vessel is above the pre-determined value. A casing surrounding the spring is connected with the escape chamber by calibrated holes whereby the pressures in the casing and chamber are equalized. In addition to the spring, fluid pressure in the chamber acts on the first face of the flap-valve. When the flap-valve is closed, the fluid pressure in the escape chamber and casing is low. Thus the flap-valve opens quickly when the fluid pressure in the vessel attains the pre-determined value. When the flap-valve is open the pressure in the escape chamber and thus in the casing is high assisting rapid closure of the flap-valve when the vessel pressure falls below the pre-determined value.