US 3643877 A
A pump of the progressing cavity type having a direct driven shredding or macerating unit combined therewith for the purpose of shredding or comminuting raw sewage or other large suspended bodies and pumping the fluids with the suspended solids therein to a holding tank and the like, as for example in recreational units such as trailers, campers, boats, and the like. A cutter element is secured to the rotor shaft at the pump intake, and coacts with a stationary cutter element surrounding the cutter intake to reduce the large and suspended solids to a state in which, while suspended in a fluid, they may be pumped.
Description (OCR text may contain errors)
O United States Patent [151 3,643,877 Zimmer 1 Feb. 22, 1972 54] PUMP WITH MACERATOR 2,512,764 6/1950 Byram ..417/412 2,658,453 11/1953 Walters... ...24l/10l X  Inventor. George H. Z1mmer, Spnngfield, OhlO 2,832,546 4/1958 Sprague 241/62 X  Assignee: Robbins & Myers, lnc., Springfield, Ohi 3,323,650 6/ 1967 Kilbane, Jr ..241/90 X  Filed: 1970 2 Primary ExaminerGranville Y. Custer, Jr.  APPLNO; 6,445 Attorney-Melville,Strasser,Foster&l-loffman  ABSTRACT  US. Cl ..24l/46.02, 241/90, 241/101  Int. Cl ..B02e 18/06 A Pump of the Progressmg cav'ty type hav'ng dlrect 58 Field of Search ..241/46.02 46.06 62 85 90 Shredding Gaming Ombined herewith 241/101 2m 202 203 2074' A pose of shredding or comminuting raw sewage or other large 48/48 suspended bodies and pumping the fluids with the suspended solids therein to a holding tank and the like, as for example in 6 recreational units such as trailers, campers, boats, and the [5 1 References Cited like. A cutter element is secured to the rotor shaft at the pump UNITED T S PATENTS intake, and coacts with a stationary cutter element surrounding the cutter intake to reduce the large and suspended solids 3,325,107 6/1967 Peterson ..241/l01 to a State i which, while suspended in a fl d they may be 2,612,845 10/1952 Byram et al.... .....4l8/48 pumpe 2,870,970 l/1959 Williamson.... ...241/260 1,030,169 6/1912 Emery ..,24l/62 X 3 Claims, 7 Drawing Figures 'PATENTEDFEB22 m2 3.643.877
SHEET 2 BF 2 FIG. 6
INVENTOR/S GEORGE H, ZIMMER ym, W W
ATTOR N EYS PUMP wmr MACERATOR BRIEF SUMMARY OF THE INVENTION With the current efforts throughout the United States to minimize pollution of natural resources and with laws being passed in many states with regard to the disposal of raw sewage in lakes and rivers from boats, it has become necessary to provide boats with holding tanks and such holding tanks are also frequently used in campers, and other recreational vehicles. Since such a waste disposal system cannot always operate by gravity, means must be provided to pump the raw sewage to the holding tank and difficulties are encountered in connection with large suspended solids.
Pumps of the progressing cavity type are known for their ability to pump solids if they are reduced to a relatively small dimension. Such pumps, for example, are used in the food industry and are capable of pumping such items as maraschino cherries without mashing them. However, for the present purpose it is necessary to provide means for shredding or macerating the suspended solids in order that they may be pumped by a pump of the progressing cavity type. The macerating of the solids also helps to prevent large particles which may clog the lines and helps in the digesting of sewage in the tank when chemicals are added.
Pumps of the type here under consideration are manufactured by Robbins & Myers Inc., and are sold under the trademark MOYNO. In such pumps the rotor and stator both have helical threads. The rotor usually has a single helical thread and the stator usually has two helical threads. The rotor may have more than a singlethread,-but the stator must have one more thread than the rotor. The rotor is usually of stainless steel or tool steel and the stator'of a rubberlike material. With such pumps the rotor and stator axes are displaced by a small amount and there must be relative movement between the rotor axis and stator axis. Pumps of this character are manufactured to operate basically in two different ways. In one, the
rotor is mounted to rotate on its own axis and the stator is resiliently mounted so that it can move in a cylindrical path as the rotor rotates.
In another embodiment, the stator is fixed and the rotor is driven through a universal joint so that the rotor while rotating has its axis moving in a cylindrical path. I
For a description of the operation and construction of the pumps here in question, reference may be had to US. Pat. Nos. 2,612,845 and 2,512,764 and others.
According to the present invention a female cutter element is mounted at the inlet of the pump in an annular fashion and a male cutter element is secured to the pump rotor in a position to coact with the female cutter element. Thus, the material being pumped must pass through the shredding unit before it enters the progressing cavities between the rotor and stator of the pump. The construction is simple and easy to service.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of atypical pump wherein the rotor rotates on its own axis and the stator is resiliently mounted to orbit about the rotor.
FIG. 2 is a cross sectional view of the pump.
FIG. 3 is a view as seen from the right, showing the male and female cutter elements.
FIG. 4 is a view similar to FIG. 2 with modified cutter elements.
FIG. 5 is a view similar to FIG. 3 showing the cutter elements of FIG. 4.
FIG. 6 is a cross sectional view of a progressing cavity type pump wherein the stator is fixed and the rotor moves in a cylindrical path within the stator if driven by a connecting rod with universal joints; and
FIG. 7 is a view of the cutter elements of FIG. 6 as seen from the left of the Figure.
DETAILED DESCRIPTION I Referring to FIG. 1, a motor is indicated at 10 and the pump housin at 11. The pump inlet is at 12 and the outlet at 13.
In F G. 2 only the pump portion of the apparatus is shown and it will be seen that a rubber or rubberlike material stator 14 having a flange 15 and the internal double threads 16 is free to wobble inside the casing 11 as necessitated by the rota tion of the rotor. The rotor shaft is indicated at I7 and the rotor itself at 18. It is mounted in suitable bearings and is provided with suitable packing in a conventional manner which need not be described because it is not necessary to an understanding of the present invention. At the inlet of the pump there is indicated at 19 a female cutter element which is fixed in relation to the casing. As seen in FIG. 3, this cutter element is provided with a plurality of teeth 20 withthe spaces 21 therebetween. A male cutter element 22 is secured directly to the rotor 18 and in the embodiment of FIGS. 2 and 3 it is a disk with blades 25 and is provided with the slots 23 and it will be observed that the periphery of the male cutter element 22 is within the female cutter element 19. It will be clear that solid materials mustbe shredded between the male and female cutter elements before they can be sucked into the progressing cavities of the pump to be pumped therethrough and out through the pump outlet 13.
The structure of FIG. 4 is substantially the same as that of FIG. 3 except that the configurations of the cutter elements are somewhat different. Here the female cutter element 19a has a much greater number of teeth and the male .cutter element 22a is provided with the radial ribs 25: The functions of the teeth 20a on the female cutter element and the slots 23a of the male cutter element are the same as in the structure of FIGS.2and3. I 1 In FIG. 6 the pump is of the type wherein the stator 30 is fixed in position and the rotor 31 orbits with its axis moving in a cylindrical path. The motor drive shaft 32 is connected to the rotor 31 through a connecting rod 33 with universal couplings 34 at each end. The pump again has an inlet at 120 and an outlet at 13a. In this embodiment the male cutter element cannot be within the female cutter element but must have frictional contact therewith or close running clearance. The female cutter element 19b is again fixed in position in the pump inlet and is again provided with the teeth 20b. The male cutter element 22b is again directly secured to the rotor 31 of the pump but in this instance it is of larger diameter so that it always is supported over a part of its bearing surface 35 against the bearing surface 36 of the female cutter element. It is provided with the slots 22c, which interrupt the otherwise sharp edge 22d at the base of the cone. In this instance also the male cutter element 22b is completely conical in that it comes to a point; but the action of the shredding device is substantially the same as in the embodiment'sabove described.
It will be clear that numerous'modifications maybe made without departing from the spirit of the invention and no limitation not set forth in the claims is intended or should be implied.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. In combination with a pump of the progressing cavity type having a casing provided with an inlet opening and an outlet opening, and comprising a fixed stator and an orbiting rotor in operative relation therewith, and means to rotate said rotor, a female cutter element fixed to said intake opening and surrounding the same, and a male cutter element secured to said rotor in operative relation to said female cutter element, said male cutter element thereby also orbiting, said female cutter element being annular and internally toothed, said male and female cutter elements having opposed smooth surfaces in contact with each other, and the parameters of said cutter elements being such that annular face-to-face contact between said cutter elements is maintained during said orbital movement.
2. Apparatus according to claim 1, wherein said male cutter element is provided with radial slots in its periphery.
3. Apparatus according to claim 1, herein said male cutter element is conical with the base of the cone constituting a sharp edge.