GB681306A - Improvements in or relating to strainers for liquids - Google Patents

Abstract

681,306. Strainers. WARDLE, J.. and WARNIC ENGINEERING CO., Ltd. April 24, 1951 [May 9, 1950], No. 11537/50. Class 46. A container of the kind in which all or part of the straining means is cleaned by reverse flow of liquid comprises a rotatable hollow straining cylinder, a tubular member extending into the cylinder and a piston device sliding within the cylinder the arrangement being such that the piston may be displaced to produce a reverse flow of liquid through part of the straining means in turn. Liquid entering at 2, Fig. 1, surrounds and passes through a cylindrical filtering medium 11 arranged on a cylinder- 4 having external ribs 5, Fig. 2, and then passes through all but four of holes 9, Fig. 2, in the cylinder 4 to cut-away parts of a flange 16, Fig. 3, on a tubular member 15 and thence into an annular space 12, Fig. 1, between the tubular member and the cylinder. It leaves by an outlet 3. The remaining liquid passes through the remaining holes 9 into and through ports 18, Figs 1 and 2, formed in the flange 16 of the tubular member 15. to a region 13, Fig. 1. From here it flows between the member 15 and a central rod 20 and reaches the filtered-liquid space 12 through ports 19. When it is desired to clean part of the medium 11 a piston 25 is raised by a handle 21 and the rod 20; during the first part of the movement a boss 24 on the piston enters the bore of the tubular member 15 thus cutting off the flow of liquid from the space 13 to the outlet. Thereafter the liquid remaining in this space is forced upwards through the ports 18, and out through the holes 9 then registering with the ports 18, and impinges on a deflector sleeve 10 mounted on the ribs 5. It then flows upwardly and downwardly in the four grooves 6a, Fig. 2, and finally out through the medium 11. The tubular member 15 is immovably secured by a plug 17 in a casing cover 1 and the cylinder 4 rests upon parts of the flange 16 of the e member 15 by means of a shoulder 14, Fig. 1. To charge the part of the medium 11 to be backwashed the cylinder 4 may be rotated about the e flange 16 by means of the handle 21 acting through an extension 26 which holds the piston 25 in place on the rod 20, is of hexagonal cross-section, and engages in a hexagonal hole in a plate 27 attached to the bottom of the cylinder. , A fixed scraper 29, Fig. 2, bears against the outside of the medium 11. In the modification of Fig. 6, the plug 17 is extended and on it is mounted a magnetic filter unit 35 past which the liquid must flow to the outlet 33. In Fig. 7 a casting 38 is closed by a removable cover plate 41 having an apertured depending wall 47 forming with the casting an annular filtrate space 43. The filter cylinder 44 is removably held as before by a flange on the tubular member 45 in this case against the lower end plate of a magnetic restraining unit 46 to which liquid gains access through slots 47. In either case the magnetic filter may be replaced or supplemented by a fine filter of fabric felt or other material.