GB760457A - Improvements in or relating to filters - Google Patents

Abstract

760,457. Filters. BEUTLER, F. A. Nov. 1, 1954 [Nov. 4, 1953], No. 31440/54. Class 46. In a filter in which a filter cake of a filtering material, e.g. kieselguhr, is deposited on the approximately vertical filtering surfaces and automatically falls off when the filtering plant is shut down, the filtering body is made of flat elements piled against each other. In the embodiment of Figs. 1-3 the flat elements 1 have thinner portions 2 with perforations 3 therein and bolt holes 4 by which they are mounted between connecting pieces 7 and tubes 6. The connecting pieces 7 have perforations connecting the perforations 3 with the inside of the tubes 6. The filter body so formed is immersed in the unfiltered liquid which will flow through the slots 8 formed between the thinner portions 2, through the canals formed by the perforations 3, and into the tubes 6 from which the filtered liquid flows out. The edges of the slots 8 are chamfered, rounded, or otherwise broken, e.g. as shown at 9-11 in Fig. 3 so that the continuous filter cake which forms on the faces of the units 5, together with the contaminations deposited thereon, will fall off said faces when the filtering operation is interrupted. Flat corrugated tapes may be used instead of the flat elements 1. In another embodiment a flat tape provided with circular perforations is used in conjunction with resilient spacing members. A horizontal section through a filter employing the latter type of element is shown in Fig. 8. The filtering chamber 20 has at one side a filtered liquid collecting chamber 26 on which are mounted rods 28. The flat elements 15 with their resilient spacer members (not shown) are mounted on the rods and are pressed together by means of screws 34. The units 31, 32, 33 are shown in their compressed, filtering condition. The filtering operation is as described above ; liquid flows through the units into the chamber 26 which has an outlet 22. The cake formed on the surface of the units falls off when the flow of liquid is stopped. This filter may be used for filtering a wetting liquid where automatic falling off of the filter cake cannot be expected. To clean the filter in such circumstances the screws 34 are loosened so that the elements 15 are separated by the resilient spacer elements, as shown for unit 35, whereby the spaces between the elements are widened to allow the passage of the filtering material and the contaminations through the filter in the normal direction of flow of the liquid.