GB392396A - Improvements in apparatus for limiting pressure of fluids - Google Patents

Abstract

392,396. Pressure-relief valves. PETIT, A., 5, Rue du Sahel, Paris. Aug. 22, 1932, No. 23429. [Class 135.] A relief valve 3, Fig. 2, is held to its seat by fluid pressure in a chamber 26 above a piston 5 on the valve spindle 4, fluid being admitted to the chamber 26 through a controlled orifice 27. When the allowable pressure in the pipe 1 is attained, a piston 29 lifts against the action of a spring 35 and a passage 37 in the spindle 31 makes communication between the chamber 26 and an exhaust pipe 2, with the result that the main valve 3 lifts. The valve 3 may be raised when desired by operating a screwed stem 40. The auxiliary piston 29 may be isolated from the main valve 3 by the introduction of a partition 42 and pipe 43. In a modification, the main valve 3, Fig. 1, is loaded by a spring 8, and pressure fluid is led to both sides of the piston 5. An auxiliary valve 13 has a stem engaging the piston 5. In operation, when the main valve 3 starts to lift, the auxiliary valve 13 opens and a pipe 22 establishes communication between the piston space 21 and the exhaust pipe 2, with the result that an added lift is given to the valve 3.