Method and means for filter back flushing

#This invention relates generally to methods of back flushing filters and more particularly to an improved back flushing filter construction which finds particular utility when used in the meat treating industry to filter liquid formulas that are injected into poultry, beef or pork by an injection machine by means of a pump that pumps the formulas into the meat through needles with small inlet and outlets.

#The prior art is exemplified by prior issued patents such as U.S. Pat. No. 2,918,172 issued Dec.22, 1959, U.S. Pat. No. 3,074,560 issued Jan. 22, 1963 and U.S. Pat. No. 3,635,348 issued Jan. 18, 1972. With the constructions disclosed and claimed in those prior art patents, filter baskets capable of either continuous or intermittent rotation are cleaned with a doctor blade and may be additionally cleaned by a back-flushing shoe disposed inside of the basket and arranged to eject a narrow jet of liquid through a localized section of the filter basket to back-flush the filter openings as they move by the shoe.

#Other prior art in the filtering art of conceivable interest includes such patents as U.S. Pat. No. 4,631,126; 4,762,615; 4,818,402; 4,931,180; 5,128,029; and 5,171,433. For example, a cleaning nozzle may be used to apply flushing liquid to a stack of discs that loosen when rotated in an opposite direction. Other forms of back wash arms are also disclosed.

#FIG. 1 is a side elevational view with parts broken away and with parts shown in cross section of a filter construction provided in accordance with the present invention and showing schematically how the filter construction is incorporated into a filtering system in order to practice the inventive methods contemplated by this invention.

#FIG. 2 is a view somewhat similar to that of FIG. 1, but showing the filter construction standing alone before installation into a tub, or tank of a filtering system.

#FIG. 3 is a top plan view of the filter construction of FIG. 2.

#Referring to FIG. 1 of the drawings, there is shown an exemplary form of a filter construction capable of practicing the methods of the present invention and connected schematically into a filtering system typical of systems used in the meat treating industry. It should be understood that the configuration of the exemplary filter illustrated for purposes of this disclosure could be changed to utilize other geometric shapes and forms without departing from the inventive features and advantages afforded by utilization of the novel concepts set forth.

#Thus, in FIG. 1 there is disclosed a filter basket 10 which provides a cylinder 20 in which moves a disc plunger 30 actuated by a pair of piston rods 40 interconnected by a piston cross bar 50 so that the disc plunger, or filter piston 30 may be operated by a motor means such as an air cylinder 60.

#Such a filter basket 10 is utilized with particular utility in a filtering system wherein the filter basket 10 is placed in a tank or tub 70 confining and containing part of a liquid stream in which flows liquid to be filtered, for example, liquid formula of the kind used in treating meat products, and which liquid stream has an input and an output. When incorporated in such a filtering system, the air cylinder 60 is operatively connected by conduits 61 and 62 to a source of pressurized air 63.