GB1122876A - Improvements in or relating to fluid filters - Google Patents

Abstract

1,122,876. Centrifugal separators; liquid filter. DONALDSON CO. Inc. 11 Oct., 1966 [14 Oct., 1965], No. 45338/66. Headings BID and B2P. A liquid filter, e.g. for treating coolant for machine tools, comprises a first housing 10 having one or more centrifugal separator elements 15, Fig. 1, an inlet pipe 17 for liquid to be treated, an outlet pipe 16 for clean liquid and liquid underflow outlet pipe 18 and a second housing 52 in communication with the first housing by means of the outlet pipe 18 and incorporating a pervious filter element 59, a restriction device 63 being provided in the underflow path, e.g. as shown at the end of a clean liquid outlet pipe 62 for filtered liquid leaving the housing 52, for regulating the amount of underflow and so as to limit the re-entrainment of particles separated from the liquid in the first housing 10 back into the centrifugal separator element or elements 15. The housings 10 and 52 are attached by brackets 14 and 53 respectively to a supporting device 13. The separator elements 15 are mounted between partitions 30 and 31 in an upper portion 11 of the housing 10. Each element 15, Fig. 3, consists of a tube 40 having a lower frusto-conical portion 42, a vortex finder 41 for the discharge of centrifuged liquid, and helical blades 45, 46 for whirling the liquid to be cleaned as it enters the annular inlet 44 in the tube 40. The portion 11 of the housing is flanged at 20 to form an elliptical cover to which is connected the lower portion 12 of the housing in the form of a detachable container into which the underflow from the separator elements 15 discharges the solid particles settling to the bottom of the container. The underflow liquid with some entrained particles leaves through the outlet pipe 18. A drain plug 26 is provided in the container 12 to drain the liquid in the container to the level of the plug to allow the container to be raised, rotated through 90‹ and tilted so that it can be detached for cleaning. The housing 52 has a similar elliptical cover 51 from which the housing can be quickly disengaged in a manner similar to that explained for container 12. The underflow liquid from the pipe 18 flows via a tube 61 to the bottom of the housing 52 where the heavier solid particles settle out. The liquid then passes through the filter element 59 and the filtered liquid leaves through a perforated tube 55 and the outlet pipe 62. The filter element is secured to the tube 55 by means of a screw 58 and may consist of a filtering member in the form of pervious metallic cylinders supported between discshaped plates with pleated filtering material between the cylinders. The restriction device 63, which may be detachable, has an orifice 64 the size of which is determined by the amount of underflow desired in the system. The underflow is usually limited to approximately 0.3 to 5.0% of the total flow through the filter.