| 摘要 |
The control valve comprises a valve stem (6) movable in a valve body (3), this stem being provided axially with two opposing recessed channels (7, 8) each leading to one end of the stem (6) and separated by a base (9), two transverse orifices (10, 11) being provided in the lateral wall of the stem on either side of the base (9), each orifice communicating respectively with a channel, a sealing member (12) held in the valve body and traversed by the stem (6), a first spring (13) adapted to force the stem (6), relative to the valve body (3), in a direction corresponding to an outward movement by the stem, and a second spring (20) disposed so as to prevent outward movement by the stem (6) as long as the pressure in the interior of the container does not exceed a predetermined value. The two springs (13, 20) are disposed in parallel, one end of the first spring (13) and of the second spring (20 ) resting against a means (14) stopped by a unilateral stop (15) of the stem, wherein this means (14) can slide relative to the stem (6) in the event of outward movement by the latter, and the second end of the first spring (13) resting against a stop (17) integral with the valve body (3), while the second end of the second spring (20) rests against a stop (21) integral with the stem (6).
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