GB413677A - Improvements in and relating to fluid filtering, screening and like apparatus - Google Patents

Abstract

413,677. Filters. BRASSERT & CO., Ltd., H. A., and HOOKHAM, G., Brook House, Walbrook, London. Jan. 14, 1933, No. 1332. [Class 46.] In filters which are cleansed by a flow of fluid passing reversely through the filter body and discharged through a fitting which is reciprocated relatively to the filter body to traverse the whole of its effective area, the flow of cleansing fluid is automatically controlled in accordance with the amount of deposit on the filtering medium by a throttle valve or equivalent device on the outlet of the fitting. A cylindrical body b, Fig. 1, with perforations, in which discs of filtering-material are held by retaining rings, is arranged in a casing a having an inlet a<2> and outlet a<3>. There is a reverse flow of filtrate into a hollow annular member e with a peripheral opening e<5> and hollow arms e' through which impurities are washed into a hollow piston rod f, reciprocated by a piston f in a cylinder g. Liquid to move the piston f<4> is supplied to each end of the cylinder g alternately through a pipe a<7> from the outlet a<3> under the control of a slide valve h which also controls the connections from the ends of the cylinder g to an exhaust pipe i. The valve h is reciprocated by pistons h<1>, h<2> to which pressure is alternately communicated from the pipe a' under control of a pilot valve h<4>. The pilot valve is operated through a lever h<6> by a rod h<7> which is moved longitudinally by the member e as the latter reaches either end of its travel. The piston rod f telescopes over a tube g<1> through which the cleansing liquid is discharged and such discharge is regulated by a valve g<4> in accordance with the difference in pressure on the inlet and outlet sides of the filter body b. For this purpose the valve g<4> is connected by levers k, l, and rods l<3>, l<4> to pistons j<1>, j<2> in a cylinder j which is in communication through pipes j<3>, j<4> with the inlet a2 and outlet a3 respectively. The speed at which the member e reciprocates is controlled by a valve i<1> on the exhaust pipe i, this valve being operated by connections from pistons m<3>, m<4>, to which the pressures at the inlet a<2> and outlet a3 are communicated through pipes m<1>, m<2> respectively. Alternatively, if it is desired to move the members e at a uniform speed the pipes m<1>, m<2> are connected to the throat and mouth of a Venturi element or similar device in the pipe supplying liquid from the outlet a<3> to the cylinder g. Fig. 4 shows apparatus in which the member e is reciprocated from an electric motor 0<4> either by means of a screwed spindle q rotated by reduction gearing or by means of a rack and pinion device. The speed of the motor may be regulated by a rheostat in the motor circuit which is controlled in a similar manner to the valve i, Fig. 1. Reference is made to apparatus in which a filter body is reciprocated relatively to a stationary discharge fitting and to apparatus in which a cleansing-liquid discharge member is reciprocated over a plane filtering surface.