| 摘要 |
<p>A valve with a tubular valve body having two axially deformable bellows disposed between two flanges and flanking an annular seat which is movable axially of the body to thereby change the effective cross-sectional area of an annular passage between its internal valve surface and the valving surface of a valve element which is secured to one of the flanges by several ribs and is spacedly surrounded by the body. The device or devices which serve to move the seat relative to the valve element are located outside of the body.</p> |
