| 摘要 |
1,208,605. Valves. WHESSOE Ltd. 14 Aug., 1968 [21 Aug., 1967; 4 Sept., 1967], Nos. 38428/67 and 40341/67. Heading F2V. [Also in Division G3] The flow of liquid through a drop pipe 31 into a vessel is controlled by a valve 34 movable between a closed position in which the liquid can flow at a limited rate through an opening 42 and an open position in which the liquid can flow at a higher rate, a releasable locking device 48 normally preventing movement of the valve, a pneumatic chamber 53 and means 39 responsive to the pressure in the chamber for releasing the locking device, a relief passage 54 communicating with the chamber 53 and having an outlet adjacent that of the drop pipe to maintain the pressure in the chamber 53 normal until the liquid level closes the outlet from the relief passage, and means 52, 51, 52 for applying a pressure differing from that of the atmosphere to the chamber 53 whereby the locking device is released when the outlet from the relief passage is closed. In operation, a cam lever 50 first lifts a valve 43 to permit liquid to flow through the opening 42 until the end of the passage 54 is closed, causing reduced pressure in the chamber 53 and movement of the diaphragm 39 to release the locking device 48. Continued rotation of the cam lever 50 now lifts a second valve 47 to equalize the pressures on opposite sides of a plunger 35 attached to the main valve 34 and subsequently lifts the main valve itself. The passage 52 may be telescopic, as shown, or may be formed by spirally wound flexible tubing and the passage 54 may be closed by a float or solenoid-actuated valve, the solenoid being energized when the vessel has been earthed. In a simplified construction, the valve (4, Fig. 1) is secured to a horizontal spring-loaded spindle (5) controlled by the locking device (20) and has permanently open passages (7, 12) to reduce the pressure in the chamber (13) when the relief passage (21) is closed by the liquid level in the vessel being filled.
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