Chopper pump with cutting inserts

#The present device relates to centrifugal pumps used for pumping liquids and slurries containing solid matter, including various types of refuse, and for chopping the solid matter which may thereafter be processed for disposal. Particularly, the device relates to a chopper pump which both effectively allows the pump to continue working during heavy chopping, provides better efficiency, and effectively reduces wear on components due to the presence of grit-like material in the liquid.

#Generally speaking, U.S. Pat. No. 3,155,046 to Vaughan, issued Nov. 3, 1964, discloses a centrifugal pump having an open impeller with radial vanes. The vane edges adjacent to the pump inlet cooperate with sharpened edges of inlet apertures to cut stringy material or chunks entering the pump. Similarly, U.S. Pat. No. 3,973,866 to Vaughan, issued Aug. 10, 1976, and U.S. Pat. No. 4,842,479 to Dorsch, issued Jun. 27, 1989, disclose centrifugal pumps having impellers with vanes cooperating with inlet apertures to achieve a chopping or slicing action of solid material in a liquid or slurry being pumped. In the case of the pumps of U.S. Pat. No. 3,973,866 to Vaughan and U.S. Pat. No. 4,842,479 to Dorsch, however, semi-open impellers having radial shroud plates are used and external booster propellers may be provided to accelerate flow into the pump. The latter, when used, helps displace chunks of solid matter which become lodged in the inlet apertures and, at least in some instances, cuts solid matter prior to entry into the pump.

#Other types of pumps having external cutters rotated with an impeller or propeller are shown in U.S. Pat. No. 2,714,354 to Farrand, issued Aug. 2, 1955; U.S. Pat. No. 3,325,107 to Peterson, issued Jun. 13, 1967; and French Patent No. 1.323.707, issued Mar. 1, 1962. U.S. Pat. No. 3,444,818 to Sutton, issued May 20, 1969, discloses another type of centrifugal pump having an internal impeller with vanes cooperating with the periphery of an inlet aperture to achieve a slicing action. In the Sutton construction, an outer “chopper member” has blades that wipe across the outer surface of the apertured intake plate to assist in chopping solid material to a size small enough to enter the intake aperture. Similarly, in the construction shown in British Patent No. 1,551,918, published Sep. 5, 1979, external blades sweep across small intake apertures to dislodge or gradually cut solid material clogging an intake aperture. In both the construction shown in the Sutton patent and the construction shown in the British patent, the external member is mounted so as to be moveable axially away from the intake plate if a hard obstruction is encountered.

#For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated.

#FIG. 1 is a side elevation of an installation of a centrifugal chopper pump in accordance with an embodiment of the present invention;

#FIG. 2 is a perspective view of an impeller assembly in accordance with an embodiment of the present invention;

#While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to embodiments illustrated.

#Referring to FIGS. 1-18, there is illustrated in the several views a chopper pump, generally designated by the numeral 10, and various components of pump 10. The chopper pump 10 has a housing 12 having an intake opening 14 and an outlet opening 16, both in fluid communication with an internal chamber 18. A similar chopper pump is illustrated and disclosed in U.S. Pat. No. 5,460,482 to Dorsch, the patent being assigned to the Assignee of the present invention. To the extent an understanding of the construction and operation of the present invention is aided by the '482 patent, the same is hereby incorporated by reference.

#As shown in drawing FIGS. 1 and 2, positioned within the chamber 18 of the chopper pump 10 is an impeller assembly 20. Generally speaking, the impeller assembly 20 comprises an impeller 22, a cutter bar plate (also referred to as an end plate or a suction plate) 26 and a back plate 28. The impeller 22 is preferably a semi-open impeller design having a back shroud 30 onto which the blades 31 and an insert cutter 24 are fixed. The impeller cutting blades 31, of which four are shown but any number of blades may be possible, are radially arranged on a first surface 32 of the back shroud 30, extending outward from a central hub 33 to the surface edge. The blades 31 are preferably kept sharpened along the top edge 34 as these blades 31 are the first and primary cutting source for the chopper pump 10.