| 摘要 |
<p>984,282. Filters for liquids. J. P. BRYDON. June 5, 1961 [June 6, 1961], No. 20225/61. Heading BID. Two filters are disposed in parallel and are associated with two valve assemblies so arranged that in one position one filter is passed in reverse through the other filter to backwash it, while in the other position the functions of the filters are interchanged. The locations of the inlet, and of the outlet (to waste), are independent of the valve positions. A pump may be provided between the two filters, and the arrangement is such that the direction of flow through it is also independent of the valve positions. In Fig. 5 unfiltered liquid is introduced at an inlet behind a valve member 16, flows from passage 6 through a filter element 2a to a passage 5, and is discharged at 14 behind a valve member 17 to the inlet of a pump (not shown). From the pump the filtered liquid is introduced at an inlet in front of valve member 17 and is deflected thereby along a passage 4 to flow in reverse through a filter element in filter 1 to a passage 3, whence it is discharged to waste past valve member 16. The valve members are secured to a common shaft 20 which may be moved to transpose the valve members by an increase in pressure differential across the filter element in use. Such increase may be sensed by a hydraulic control system 30, Fig. 6, which operates a hydraulic motor 21, Figs. 5 and 6, having a rotor 24 keyed at 25 to shaft 20. Instead of the hydraulic motor there may be provided on shaft 20 a toothed pinion driven by an electric motor through a worm gear, the motor being set in operation by a mercury switch tilted by a flexible diaphragm on attainment of the necessary pressure differential. A disc with conducting surfaces constituting a holding switch is also carried by the shaft 20, Figs. 2 and 3 (not shown). In Fig. 7, each valve assembly consists of two pairs of hydraulically-operated lift valves, the valves in each pair being so arranged that when one is open the other is closed. They may be operated by a control system 30 identical with that in Fig. 6. The invention may be applied to the bilge system of a ship so that the filters, probably being in inaccessible locations, may be cleaned in situ.</p> |
