GB707718A - Improvements relating to liquid filters - Google Patents

Abstract

707,718. Filters. DOWTY EQUIPMENT, Ltd. July 25, 1952, No. 18910/52. Class 46 A filter comprising an open-ended container 5, Fig. 1, for a filter element 21, a head fitting 14 forming a closure for the container and including inlet and outlet passages 35 and 36 respectively, Fig. 3, communicating respectively with opposite sides of the filter element, has an isolating valve, 39 or 41, in each passage and a valve actuating means, e.g. a ported plate 28, is provided and is operated by relative movement between the container and the head fitting. The valves are spring-loaded to closed position, Fig. 3, when a turn-key 18 is rotated to unscrew it from a threaded bushing 9, Fig. 1, at the upper end of a tube 8 fixed in the container 5, the resulting downward movement of the bushing 9 (with the container) permitting the plate 28 to slide down to its lowermost position on the turn-key 18, where it is held captive by a shoulder 18a. A seal 17 between the head fitting 14 and the inner face 12 of an extension 11 on the container 5, together with the length of screw engagement between the bushing 9 and turn-key 18 ensure that the container 5 and the head fitting 14 are not completely separated until the isolating valves are closed. A bye-pass valve 49, Fig. 3, is provided. In the assembled condition the filter element 21 is urged into contact with the plate 28 by a spring 24 acting between a shoulder 7a on a hollow spigot 7 of the container 5 and a shoulder 23a on a radially-flanged sleeve 23 on which the filter element 21 rests, the sleeve being retained on the spigot 7 by a circlip 25. In use liquid flows from inlet passage 35, past valve 39, through ports 33 in the plate 28 to the outside of the element 21 and leaves from the inside through ports 34, valve 41 and passage 36.