Automatic pressure-equilibrating valves

Claim 1

A valve adapted to afford passage of a fluid in either direction when the difference in pressure between the media located ahead of and before the valve rises beyond a predetermined value, chiefly in order to equilibrate the pressure inside a closed and fluidtight chamber with reference to the outer environment, said valve comprising a preferably cylindrical sleeve secured fluidtightly to the wall of the closed chamber through which it passes perpendicularly, while the ends of said sleeve open respectively into the outer environment and into the chamber, a cylinder coaxially fitted in the sleeve and adapted to move longitudinally therein, a yielding annular packing fitted inside one end of the sleeve so as to form an elementary valve affordIng a passageway in a single direction, a coil spring urging said cylinder against said packing, and a second elementary valve affording a passage of the fluid in the opposite direction, said second elementary valve including a dished member or socket, a further spring urging said socket and engaging the end of the cylinder facing the first-mentioned packing and urging said socket against another annular packing in floating position in the other end of the cylinder against an annular inwardly projecting rib in the opposite end of the cylinder, the two springs acting in opposed directions.