| 摘要 |
<p>917,182. Control of several motors. HIRS, G. Feb. 13, 1961 [June 20, 1960], No. 5260/61. Drawings to Specification. Class 38 (3). [Also in Group I] In an apparatus including a tank which houses several filter elements connected to a manifold, and is provided with a conveyer for removing sludge which settles after being scraped from the elements (see Group I), liquid to be filtered is supplied by a motor-driven pump and filtrate is pumped from the manifold. On clogging of the filter elements, the resulting pressure drop in the manifold causes a bellowsoperated switch to close, thereby initiating automatically a cleaning cycle. First the inlet and outlet pump motors are stopped, and a solenoidoperated drain valve is opened to permit the liquid to return to the vessel from which it was pumped. After a pre-set interval governed by a timer, the conveyer motor is switched on and, simultaneously, a solenoid-operated valve is energized to admit air to a cylinder-and-piston assembly which operates the filter-element scrapers. After a further pre-set interval governed by a second timer the air-cylinder valve is de-energized to permit return of the scrapers to normal position. After a further pre-set interval governed by a third timer, the conveyer motor is stopped and the remaining parts of the circuit are restored to normal condition so that filtration re-commences.</p> |
