| 摘要 |
<p>1522892 Automatic control of pressure ETABS POMPES GUINARD 14 April 1976 [15 April 1975] 15288/76 Heading G3R A physical variable e.g. water pressure is maintained at the desired level by varying the number of pumps P 1 -P 3 in response to a pressure detector 1. Pumps P 1 -P 3 are connected between supply lines L 1 and L 2 by starting contacts 8 and also by continuous supply circuits e.g. 13, t 1 , R 1 . A low pressure causes the starting circuits of each pump in turn to be energized by rotation of cams 7 1 -7 3 after which the continuous supply circuits hold the pumps on. A high pressure on the other hand causes timer T to be energized. This cuts out each continuous supply circuit in turn, according to built in delays, via contacts t 1 -t 3 leaving only that pump which happens to have its starting circuit energized, operative as a holding pump. A timer T' ensures that the pump starting cams 7 1 -7 3 always come to rest in such a position that when they are next rotated a pump will be started immediately.</p> |
