| 摘要 |
<p>The valve has two closure discs (22, 23) carried by a spindle (16) which can move the discs into and out of the pipeline passage (1), and device (18) moves these away from or towards one another to press them on to or lift them off their seats (4). The device (18) is combined with resilient elements, such as spring (21) or a pressurised flow medium, to hold the disc on their seats with a pre-determined force which is not dependent on the reaction force from the seats on the discs. The device (18) may comprises a cam or eccentric between the discs acting on each via a spring (21).</p> |
