| 摘要 |
<p>1499160 Valves LA TELEMECANIQUE ELECTRIQUE 24 Sept 1975 [22 Nov 1974] 39097/75 Heading F2V A delay timer for a valve 30 has; a shutter movable between first and second positions a, b in a preset time determined by a delay means 25, 27; means 10 responsive to control pressure applied via a first conduit 40 which is connected to a second conduit 49 through a throttle 41 and to exhaust 19 via an opening 43; and a tubular member 4 linked with means 10, resiliently biased (e.g. by a spring 15) towards an end closing contact with the shutter, and movable away from the shutter to make connection at its opposite end with the opening 43. The delay means may have a spring loaded bellows 24, 23 with a throttling tube 25 of variable effective length adjustable by a knob 22. In operation, with zero control pressure at E, tube 4 is at a with an orifice 11 at its end closed by the shutter, and the valve 33, 34 is closed. Application of pressure at E moves tube 4 to b connecting pressure to orifice 11 via passages 49, 43, 14. Admission of air to the timer via throttle tube 25 allows the bellows to expand and seal the orifice 11 after a time dependant on the timer setting. A membrane 31 is then deflected by the increasing pressure in a chamber 42 to operate the valve 30. In a modification, Fig. 3 (not shown), an opening (48) in the tubular member replaces the throttle 41 and an opening (51) provides for exhaust from chamber 42. A further modification, Fig. 4 (not shown), converts the apparatus to give delayed operation a fter control pressure cut off.</p> |
