Patent ID: 7104277

Claim:
A control valve (C) of the internal gas pressure of a liquid tank, cooperating with an orifice ( 10 ) made in the upper part of the tank, permitting gas flow to the exterior of the tank, when the difference between the internal pressure and external pressure reaches a predetermined threshold, and inverse flow, when the internal pressure in the tank is less than the external pressure, comprising: a body ( 1 ), whose lower part is configured to block orifice ( 10 ) of the tank with a weight, so that, beyond said differential pressure value, which represents the predetermined threshold, body ( 1 ) is separated from the orifice ( 10 ), wherein said body ( 1 ) also contains a recess ( 4 ) arranged in the continuity of and substantially axially aligned with the orifice ( 10 ) of the tank when the body and the orifice are in contact, said recess ( 4 ) being equipped with means of blocking ( 3 ) that are activated when the differential pressure between the tank and atmosphere is positive.