GB875403A - Filtering apparatus for liquids - Google Patents

Abstract

875,403. Liquid filters ; liquid circulatory systems. INDUSTRIAL VACUUM CLEANERS Ltd. Feb. 26, 1960 [Jan. 20, 1959], No. 2120/59. Class 46. A liquid filtering apparatus, for use in liquid circulating systems, comprises a bore 1 with a tank mounted thereon and having an upwardly projecting filter chamber 3 whose outlet compartment, separated from the inlet compartment 4b by a filter element E supported on a resilient perforated wall 4 of conically re-entrent truncated cone form, is in direct communication with the tank. A centrifugal pump 16 driven by an electric motor 17 is arranged to deliver the liquid, to be filtered under pressure, to the inlet compartment and there to force it through the filter element E. A bleed passage 23 carries air trapped in the inlet compartment 4b, and a small quantity of liquid, back to the suction side of the pump 16, the cross-section of the passage 23 being too small to materially affect the performance of the pump 16, but sufficient to prevent accumulation of air in the inlet compartment 4b. The filter wall 4, which flexes under changes of pressure in the inlet compartment 4b and therefore tends to cause the filter element E to shed accumulated material, has a radially directed annulus A fitted with a plastic gasket G having a flap F overlapping the filter E, the gasket G cooperating with the radial flange B and a flexible gasket H, registering with a circular groove in the detachable lid 5 to ensure a pressure tight filter chamber 3. Any liquid which might leak past the gaskets G and H is collected in a circular groove J and returned via an overflow pipe K to the pump 16. An elbow 7 which forms the end portion of the flexible inlet pipe 8 from the pump 16 fits into a central aperture of the lid 5 and carries a pressure gauge 9, a pressure sensitive switch 9a and a pair of trunnions 10 by which it is pivotally secured between the tines of a bifurcated arm 11, Fig. 1, (not shown), pivoted at 12 to a bracket 13, rigid with the filter chamber 3, the weight of the lid and its associated parts being balanced by the tensional force of the spring 14. A flexible pipe 21 connected to the inlet aperture of the pump 16 has a flange for connection to the outlet passage of a machine tool using liquid coolant which may be pumped to the machine tool by a second pump fixed into the tank through an aperture, another aperture being used for inspection and refilling of the tank with liquid coolant. The electric motor 17 is controlled by switchgear responsive to the pressure in the inlet compartment 4b through the pressure responsive switch 9a. The lid 5 has a number of outwardly directed peripheral tongues C which on rotation of the lid 5 lock in to position beneath their counterparts D protruding inwards from the upper periphery of the filter chamber.