| 摘要 |
<p>1,122,842. Valves. REAVELL-FAHIE Ltd. 10 Aug., 1965 [10 Aug., 1964], No. 32489/64. Heading F2V. In a double-beat lift valve, hydrostatic balance is obtained by providing equal-diameter guided extensions on each closure member, and hydrodynamic balance over the range of valve lift is obtained by choosing the contours and heights of the closure members, as measured in the direction of valve lift, individually but in mutual relationship. Use is made of the fact that, as the height of the closure members of a double-beat valve is increased, the opening force exerted by the fluid at the beginning of the opening movement gradually diminishes and ultimately reverses to become a closing force. The two closure members thus have different heights and contours to achieve substantial hydrodynamic balance over the range of lift. Suitable shapes are suggested. The closure members can abut the seats or slide in and out.</p> |
