| 摘要 |
A control valve (C) for controlling the internal gas pressure in a liquid tank, for use in conjunction with at least one port (21) in the upper portion of the tank, and comprising a body (1) with a through-bore (4) communicating with said port (21) and provided with seal means (3) actuated when the pressure inside the tank exceeds the pressure outside same, wherein said body (1) can be caused to move by a pressure differential higher than a predetermined threshold between the inside and outside of the tank, said body (1) is slidable inside the inner chamber (22) of a casing with two openings (8, 10) respectively communicating with the outside and with the tank (R), between a first position in which it engages a seat (12, 12') around the inside rim of the opening (10) connected to the tank (R), which first position prevents any outward gas flow, and a second position in which it is spaced apart from said seat (12, 12') so that said outward gas flow is possible, and return means (7) are provided for urging the body (1) into engagement with the seat (12, 12'), which means are calibrated in such a way that contact is maintained until the pressure differential threshold is reached. The seal means in the body (1) of the valve (C) consist of a lightweight movable member (3) freely translatable with a degree of radial clearance in one portion of the through-bore (4), and movable between a seat (6) on the same side as the return means (7) for sealing the through-bore (4), and an abutment (5) on the same side as the opening (10) connected to the tank (R), no sealing function being provided during contact therewith. |
