Material reduction means for pumps

A pump adapted to ingest, reduce and deliver combined fluid and solid materials. The pump includes a centrifugal pumping means with a volute chamber, central inlet opening, a substantially tangential outlet opening and a vaned rotor within the chamber; a milling means at and about said inlet opening and including an elongate milling ring with upstream and downstream ends and elongate circumferentially spaced grooves and teeth about its inner peripheral portion and a milling disc rotatable within the ring and drivingly coupled with said rotor, said disc carrying circumferentially spaced shearing blades overlying the downstream end of the ring and shearing blocks with circumferentially and radially disposed material engaging surfaces within the confines of the ring; and material feed means to reduce and deliver material to the milling means and including a material conducting bore upstream of the milling ring, a lateral material supply duct communicating with the bore and an elongate helical screw in the bore and drivingly coupled with the disc and a prime mover drivingly coupled with one end of that rotary assembly made up of said rotor, disc and screw.

This invention has to do with an improved waste reducing and pumping means 
and is more particularly concerned with a fluid pump induction means 
having solid waste milling and reducing capabilities. 
Throughout the various arts where fluids and large particles and/or pieces 
of solid matter are likely to be combined and where the moving and 
disposal of the combined fluids and solids is required, it has long been 
common practice to provide means to separate the solids from the fluids 
for independent disposal of each. The above practice has been followed due 
to the fact that strict limits are placed on the size of solid matter that 
can be discharged into fluid waste disposal systems such as sewers and due 
to the fact that conventional pumping means provided to effectively move 
fluids cannot effectively or efficiently move large pieces of solid matter 
and tend to become jammed and/or plugged thereby. 
In recent years, several special pumps provided with grinder means at their 
inlets have been provided by the prior art. The grinder means in such 
pumps serve to grind up or to reduce solid matter carried by the fluids 
drawn into the pumps. The grinder means are intended to reduce the size of 
the solids encountered to a size which will not adversely affect the 
operation of the pumps and to a size which is below the largest 
permissible size of solid matter than can be discharged into the waste 
systems to which the discharge of the pumps is directed. 
One of the above noted pumps with grinder means is disclosed in my U.S. 
Pat. No. 3,128,051 issued Apr. 7, 1964, and entitled PUMP. Another such 
pump is disclosed in U.S. Pat. No. 3,650,481 entitled GRINDER PUMP and 
issued to William J. Conery, et al on Mar. 21, 1972. 
The structures of the above noted prior art Pump and Grinder Pump comprise 
centrifugal pumps with annular, grooved, milling rings arranged at the 
inlet passages or openings of the pumps and milling discs with material 
engaging protruberances rotatably arranged within the rings and drivingly 
coupled with the rotors of the pumps. While the above structures are 
effective to mill and reduce some solids carried by the fluids drawn into 
the pumps, they are often slow to reduce the solids and are readily 
plugged and jammed by commonly encountered fibrous materials such as rags, 
bandages, sanitary napkins, pantyhose and the like. Further, the size of 
solid matter which these prior pump structures can effectively handle or 
ingest is quite limited. 
It has been found that most soft long fibre materials such as fabrics or 
rags and many vegetable fibres tend to collect on and about the milling 
discs and are not effectively caused to move and advance between the discs 
and their related milling rings. Such materials often accumulate and build 
up sufficiently to impede the flow of the fluid carrier into the pumps to 
such an extent that the pumps lose prime and the structure are rendered 
inoperative. 
It has also been found that large objects such as sticks frequently become 
bridged across the inlet end of the milling means of such prior art pumps 
and establish structure on which other foreign solid materials become 
lodged to plug and foul the pump structure. 
In the above noted prior art pumps, the time it takes for the milling means 
to reduce hard solid particles to a size which will permit them to pass 
between the milling discs and rings is often extensive and such that it is 
not infrequent that hard materials will accumulate faster than they can be 
reduced. When this takes place the pump structures become fouled and fail 
to function as intended. The slow milling and/or reducing action is a 
result of the fact that hard to reduce materials tend to be kicked or 
knocked about substantially freely within the milling rings by the discs 
and/or the material moving protruberances thereon. But for the flow of 
fluid drawn through the milling means by the pumps, there is no material 
feed means for advancing the solids into the milling means. 
It is not infrequent that the pumps of the prior art noted above must be 
let to run or operate for exceedingly long periods of time to effect 
reduction and disposal of a rather small quantity of solid matter. Such is 
not only inefficient with respect to time but it is inefficient with 
respect to power consumption and oftentimes with respect to the volume of 
fluid that must be used to effect flushing and/or carrying of the reduced 
materials away. 
The milling rings provided in the noted prior art pumps are of substantial 
axial extent and are provided with a multiplicity of circumferentially 
spaced radially inwardly opening and axially extending fluid and solid 
material conducting grooves, which grooves define intermediate radially 
inwardly projecting, axially extending milling ribs with radially inwardly 
disposed inner faces and sharp corner edges. The milling discs are of less 
axial extent than the rings, have cylindrical outer edges and are 
rotatably supported in the rings with running clearance and adjacent the 
downstream ends of the rings. The discs are next provided with a plurality 
of fixed, circumferentially spaced, axially projecting protruberances at 
their upstream ends or surfaces. The protruberances have substantially 
circumferentially disposed surfaces and edges that oppose the ring with 
running clearance. When the discs rotate, the protruberances strike and 
move pieces of solid material within the ring in and about the ring to 
effect milling or reduction of such matter. As the protruberances move 
circumferentially and by the milling ribs on the rings, they shear any 
solid material advanced into and which projects radially inwardly from the 
grooves. 
In practice, it is not infrequent that matter within the cutting rings in 
the prior art pumps and engaged by the protruberances is such that the 
protruberances fail to shear it and the milling means are jammed, that is, 
the milling discs are stopped. Such can happen when hard or tough solid 
matter is encountered, such as pices of bone, metal and certain plastic 
materials. Such jamming also occurs when tough long fibre solid materials 
such as fabric, jute and straw are encountered. 
In addition to the above, the milling means of the noted prior art pumps 
are provided with a plurality of circumferentially spaced shearing blades 
directly or indirectly related to the milling discs. The shearing blades 
project radially outwardly from the discs to occur adjacent the downstream 
ends of the milling rings to move by the downstream ends of the grooves 
and ribs of the rings and to cut and/or shear solid material moving 
downstream and out through the grooves. In the case of the above noted 
Smith patent, the shearing blades are defined by the veins of the 
centrifugal pump, while in the noted Conery, et al. patents, the shearing 
blades are defined by the ends of fluid moving veins of an axial flow 
inducer means interposed between the milling disc and the pump rotor. 
An object and feature of my invention is to provide an improved pump with 
improved material milling means at the inlet of the pump and with material 
feed means upstream of said milling means. 
It is an object and feature of my invention to provide a pump of the 
character referred to which is such that solid materials upstream of the 
milling means is forcibly moved downstream into and through the milling 
means whereby such matter is not subject to collecting and building up in 
the milling means so as to plug and foul the construction. 
Yet another object and feature of this invention is to provide a pump of 
the character referred to which is such that the material feed means cuts 
and reduces the size of solid matter advanced to the milling means to a 
size which will not effectively bridge across the upstream end of the 
milling means and to a size which is such that the milling means can 
effectively, rapidly and efficiently reduce such material for free and 
effective movement into and through the related pump. 
Still another object and feature of my invention is to provide a milling 
means including milling blocks on the milling disc to oppose the milling 
ring, which blocks are shiftable radially inwardly whereby they are free 
to move inwardly and ride over hard solid pieces of material which engage 
between the milling ring and the blocks and which are not immediately 
sheared thereby, whereby such pieces of material will not jam and foul the 
construction. 
It is another object and feature of the present invention to provide a pump 
of the character referred to above wherein the milling means includes 
shearing blades and the disc, which blades project radially outwardly 
adjacent the downstream end of the ribs and grooves of the milling ring to 
shear matter moving downstream through and from the grooves in the ring. 
An object of my invention is to provide a pump of the character referred to 
wherein the material feed means includes an elongate helical screw with a 
cutting edge drivingly coupled with and extending upstream from the 
milling disc and pitched to advance material downstream, a fluid 
conducting body or chest about the screw and having axially spaced 
radially inwardly projecting helically curved shearing ribs arranged and 
disposed to cooperate with the cutting edge of the screw to cut and shear 
large pieces of material which exceed a size that can be effectively 
worked upon by the milling means. 
It is an object and feature of my invention to provide a pump of the 
character referred to wherein the pump with which the milling and feed 
means are related is a centrifugal pump having a rotor drivingly coupled 
with the milling disc with which said screw is drivingly coupled and a 
pump structure wherein a single prime mover is coupled with an end of the 
assembled rotor, disc and screw.

Referring to the drawings, the pump that I provide includes fluid pumping 
means P, milling means M, feed means F and a prime mover E. 
The means P, M and F are elongate means with upstream and downstream or 
front and rear ends and are arranged on a common central axis, in end to 
end relationship. 
The pumping means P is a substantially conventional centrifugal pump 
structure having a stationary external case 10, defining a radially 
extending volute chamber 11, a radially extending rotor 2 with vein 14 and 
an elongate central, axially extending shaft 15 rotatably supporting the 
rotor within the chamber. 
The pump means is at the downstream end of the construction and its case 10 
is provided with a central large diameter inlet opening 16 at its front or 
upstream end. The case 10 next includes a discharge passage 17 extending 
tangentially from the chamber and through a laterally projecting discharge 
neck 18. The neck 18 is provided with a coupling flange 19 to facilitate 
connecting the pumping means with a waste pipe 20, or the like, 
substantially as shown. 
The shaft 15 is rotatably supported by a bearing 20 in a recess 21 provided 
in the downstream end or wall of the case. A suitable seal 22 is provided 
in the recess 21 and about the shaft 15, forward of the bearing 20. The 
shaft 15 has a front or upstream end portion which projects freely through 
and from the inlet opening 16 to connect with the means M, as will 
hereinafter be described. 
Finally, the case 10 of the pump means P has a mounting flange 24 at its 
front or upstream end about the opening 16 to facilitate connecting the 
case 10 with a body or chest C. 
The milling means M that I provide is arranged within the chest C and 
includes an annular milling ring R adjacent to and concentric with the 
inlet opening 16 of the pump means P and a rotatable milling disc D within 
the ring and drivingly coupled with the shaft 15. 
The details of construction of the means M will be considered following 
description of the feed means F. The feed means F that I provide includes 
the above noted elongate chest C. The chest C has front and rear or 
upstream and downstream ends. The chest C defines a central longitudinal 
bore 25 and is provided with lateral tubular inlet neck or duct 26 
communicating with the bore 25 intermediate the ends thereof. The duct 26 
and the upstream and downstream ends of the body are provided with 
mounting flanges 27, 28 and 29, respectively. 
The flange 29 is engaged with the flange 24 of the pump case 10 and is 
secured therewith by suitable screw fastening means, substantially as 
shown. The bore 25 of the body B is concentric with the axis of the pump 
means and is arranged with its downstream or rear end in communication 
with the inlet opening 16 of the pump means. The flange 27 on the inlet 
duct 20 is engaged with a complimentary flange 27' on a fluid supply duct 
30 which serves to conduct liquids and solids to be worked upon into the 
feed means F. 
The flange 28 at the rear or upstream end of the body B is engaged with a 
complimentary flange 28' on a journal plate J related to and closing the 
front or upstream end of the bore 25. 
The chest C is not unlike a T-fitting and is such that the upper portion of 
the bore 25 is interrupted by the duct 26 which communicates therewith. 
The lower portion of the bore 25 is provided with a plurality of axially 
spaced radially inwardly projecting and axially helically pitched cutting 
ribs 31 with flat radially extending axially disposed flanks and flat 
radially inwardly disposed axially extending lands which converge with 
said flanks to define sharp cutting edges 32. 
The feed means F next includes an elongate screw S arranged concentrically 
within the bore 25. The helical thread of the screw has a straight 
cylindrical radially outwardly disposed land and axially inclined or 
curved flanks establishing valleys of substantial radial extent or depth. 
The diameter of the screw is such that the lands or ridges 35 of the 
thread are spaced radially from the bore 25 and occur in close shearing 
proximity to the lands or cutting edges 32 on the ribs 31. The downstream 
or rear end of the screw S is provided with a threaded axle pin 36 to 
engage the disc D of the means M, as clearly shown in the drawings and as 
will hereinafter be described. 
The upstream or front end of the screw S is provided with an axle pin 37 
which pin projects freely through the aforementioned journal plate J 
secured to the front end of the body and which closes the front or 
upstream end of the bore 25. The plate J carries a bearing 38 and a seal 
39 to rotatably support and seal about the pin 37. 
While the screw S is similar to an Archimedes screw, within the bore 25, 
its primary function is to first shear, shred or reduce solid material 
introduced into the bore 25 through the inlet duct 26 and to thereafter 
advance that material downstream or axially rearwardly into working 
relationship within the means M. 
The inlet duct 26 is a large diameter duct and communicates with one side 
of the bore 25 to substantially eliminate or open that side of the bore 
whereby the bore is only about 180.degree. in circumferential extent 
throughout its major longitudinal extent and is open, laterally, so as to 
freely receive large objects or pieces of solid material. 
The axially spaced ribs 31 are also little more than 180.degree. in 
circumferential extent and occur about the lower portion of the bore or 
about that side of the bore which is opposite the duct 26. 
With the above relationship of parts, solid material moving laterally into 
the bore 25 of the chest from the duct 26 is free to move between the ribs 
31 and into the valleys of the screw. When such material becomes engaged 
in and between the flanks of the screw and the ribs and as the screw is 
rotated, the material is effectively sheared and/or reduced and is also 
advanced downstream toward the milling means M. The lateral feeding of 
material into the means F is highly effective and desirable since long 
pieces of solid material such as sticks of wood and the like, which could 
not otherwise enter between the bore and the screw can be advanced 
therebetween, a portion at a time, and can be effectively reduced thereby. 
The journal plate J at the front or upstream end of the body B is provided 
with a mounting flange 40 on which the prime mover E is mounted. The prime 
mover E is preferably an electric motor of suitable design and size and is 
drivingly coupled with the pin or shaft 37 of the screw S by conventional 
drive coupling means (not shown). 
Referring once again to the milling means M, the milling ring R is an 
elongate angular ring, rectangular in cross-section. The ring has an 
exterior cylindrical surface 50, flat radially extending front and rear 
ends 51 and 52 and a cylindrical inside surface 53. The radial outer 
portion of the ring is plain or uninterrupted while the radial inner 
portion of the ring is provided with a plurality of circumferentially 
spaced axially extending and radially inwardly opening fluid conducting 
grooves 54. The grooves 54 in the ring define a plurality of 
circumferentially spaced radially inwardly projecting, axially extending 
shearing teeth 55. The surface 53 of the ring defines longitudinally 
straight radially inwardly disposed lands on the teeth 55 while the 
grooves 54 cooperate to define the opposing flanks of adjacent teeth. The 
flanks and lands of the teeth converge to establish sharp longitudinally 
extending cutting edges on the teeth. 
The radial outer portion of the ring R is seated in a radially inwardly 
axially rearwardly opening annular seat 56 formed in the rear or 
downstream end of the chest C of the means F. The seat 56 is established 
in a counter bore 57 at the downstream end of the bore 25. The counter 
bore 57 is larger than the bore 25 and defines a milling chamber into 
which the grooved and toothed radial inner portion of the ring projects. 
In practice, as shown in FIGS. 4 and 5 of the drawings, a set screw 58 is 
provided to lock or set the ring R against rotation in the seat. The set 
screw 58 is engaged through the chest from the exterior of and projects 
radially inwardly into a cavity or opening provided in the exterior of the 
ring. 
The ring R is retained in the seat 56 by the flange 24 of the pump case 10. 
The radial inner portion of the flange 24, adjacent to and defining the 
pump inlet 16, overlies the outer radial portion of the rear surface 52 of 
the ring, radially outward of the teeth 55 and grooves 54 of the ring. 
The milling disc D includes a substantially flat radially disposed assembly 
comprising a flat downstream or rear plate 60 and a front or upstream body 
61. 
The plate 60 is a flat steel plate with front and rear surfaces 62 and 63, 
an outer edge 64 and a central opening 65. Additionally, the plate 60 is 
provided with a plurality (4) of circumferentially spaced radially 
outwardly projecting shearing blades 66 with radially extending cutting 
edges disposed circumferentially in the direction of rotation of the disc. 
The diameter of the plate is slightly less than the inside diameter of the 
ring R and the cutting blades 66 are substantially equal in radial extent 
with the radial extent of the teeth 55 and grooves 54 of the ring R. 
The plate 60 is arranged or positioned axially of the construction so that 
its front surface 62 is in substantially but slightly downstream or 
rearward of the rear surface 52 of the ring R whereby the blades 66 move 
circumferentially by the teeth and by the grooves of the ring when the 
disc rotates. 
In practice, a close running clearance is provided between the cutting 
blades and the ring so as to avoid or prevent adverse wearing of the ring 
and/or blades. 
The body 61 of the disc D is a cast or forged steel part with front and 
rear surfaces 70 and 71, a substantially cylindrical side surface 72 and a 
central threaded opening 73. In addition, the body is provided with a 
plurality (4) of circumferentially spaced radially outwardly and axially 
rearwardly opening recesses 74. In the preferred carrying out of the 
invention, the exterior of the body is provided with a plurality (4) of 
radially outwardly disposed flats 72' at which the recesses 74 enter. 
The body 61 is arranged within the ring R, with running clearance and with 
its rear surface 70 in flat bearing engagement with the front surface 62 
of the plate 60, whereby the rear sides of the recesses 74 are closed by 
said plate. 
The plate and body are secured together in tight relationship and against 
relative rotation by screw fastening means 75. 
The forward end of the pump shaft 15 is threadedly engaged through the 
opening 65 in the plate and into the openings 73 in the body from the rear 
end thereof whereby the disc is drivingly coupled with the pump. The axle 
pin 36 on the rear end of the screw S of the feed means F is engaged in 
the opening 73 in the body from the front end thereof, whereby the disc D 
and the screw S are drivingly coupled together. 
In addition to the foregoing, the disc D of the means M includes a 
plurality (4) of elongate radially extending shearing blocks 80 slidably 
engaged in the recesses 74. 
The recesses 74 are preferably substantially square in cross-section and 
the radial inner end portions of the blocks 80 are substantially square in 
cross-section and are slidable into and out of engagement in the recesses. 
The radial outer end portions of the shearing blocks 80 project outwardly 
from the recesses and from the body at the flats 72' and have radially 
outwardly disposed outer ends 82 which normally oppose the inside surface 
53 of the ring R in close running clearance. 
The end surfaces 81 of the blocks cooperate with the flat sides of the 
blocks to define sharp axially extending cutting edges 83 which are 
parallel and oppose sharp cutting edges defined by the teeth 55 of the 
ring R. 
The longitudinal extent of the blocks 80 is such that when the blocks are 
in their normal position, at least two-thirds of the blocks occur within 
and are supported and guided in their related recesses. Further, the 
blocks are of such longitudinal extent that when they are in their normal 
position, the radial inner ends 84 of the blocks are spaced from opposing 
inner ends 85 in the notches, a substantial distance whereby the blocks 
are free to shift radially inwardly from their said normal position. 
In practice, and as shown in the drawings, the radial outer end portions of 
the blocks are formed so that the axial extent of their outer ends is 
substantially equal to the axial extent of the ring R whereby the blocks 
cooperate with the teeth of the ring throughout the entire longitudinal 
extent of said teeth. 
Finally, the means M that I provide includes stop means to limit radial 
outward shifting of the blocks 80 relative to the disc and to normally 
retain the blocks in their normal working position relative to the ring R. 
The stop means can vary widely in practice and is shown as including an 
elongate radially extending axially inwardly opening slot 86 in each block 
and stops 87 carried by the plate 60 and projecting axially forwardly 
therefrom and into the slots 86, The stops 87 are shown as simple screw 
fasteners engaged through and carried by the plate 60. 
While the annulus between the disc D and ring R, established by the working 
clearance provided, affords for the flow of some fluid downstream through 
the means M, the grooves 54 in the ring provide for the principal flow of 
fluids and solids through said means. The cumulative cross-section of the 
noted annulus and the grooves 54 is substantial and is adequate with 
respect to the flow capacity of the pump means P that is provided. 
It is important to note that the flats 72' about the perimeter of the disc 
D cooperate with the ring R to define axially forwardly opening segmental 
recesses of substantial radial extent into which rather large objects or 
pieces of solid material is free to enter and into or which the blocks 
freely project. 
In operation, when a piece of solid material enters between the disc D and 
the ring R and is engaged between a shearing block carried by the rotating 
disc and a tooth on the fixed or stationary ring, it is, under ordinary 
circumstances, sheared and reduced to a size which will freely move 
axially downstream through the grooves and into the pump means. Should 
such a piece of material stopped on a tooth be sufficiently tough and hard 
so that it is not immediately sheared by the block which first engages it, 
that block is free to shift radially inwardly and to ride over or move by 
that piece of material, whereupon the next advancing block will strike and 
shear or reduce it in size. 
In practice, it has been found that if a piece of material stopped against 
a tooth is not sheared by the block which first engages it, the second 
block most frequently will shear it. If the second block to engage the 
hard material fails to shear it, the third or fourth block to engage it 
will shear or otherwise reduce it. 
Of equal and possibly greater importance than the ultimate shearing and 
reduction of hard objects or pieces of solid material in the manner set 
forth above is the ability of the shearing blocks to ride over such 
objects in such a manner that the construction is not jammed and stopped 
by such objects. 
As a result of the ability of the blocks to ride over hard objects and to 
repeatedly work on such objects to reduce them, the construction need not 
be constantly monitored by an attendant for the purposes of turning the 
power off before the prime mover is burned out and for the purpose of 
dismantling and cleaning or freeing the construction of such objects. 
It is to be noted and it will be apparent that the blocks are normally 
urged and held out in their normal position by centrifugal force. 
Accordingly, the need for spring means or the like to normally yeildingly 
hold the blocks in their normal position is not ordinarily required. 
The cutting blades 66 on the plate 60 of the disc D are such that when they 
move by the teeth 55 of the ring R and engage solid material advancing 
downstream and out of the grooves 54 of the ring, they cooperate with the 
teeth to effectively shear and reduce that material. The cutting blades, 
working as noted above, are particularly suited and effective to cut and 
shear long pieces of fibrous material which tend to move longitudinally 
downstream through the grooves, free of the shearing blocks and which 
would tend to collect on and about the pump rotor and to plug and foul the 
pump means. 
In operation of the construction, a mixture of fluid and solid material is 
conducted to the inlet duct of the chest C and is directed into the bore 
25 where it is enaged and worked upon by the screw S. The screw S 
cooperates with the ribs 31 in the bore to cut and reduce large pieces of 
solid material and advances all solid materials and fluid downstream into 
the milling means M. The milling means M mills and further reduces the 
size of the solid material delivered to it by the feed means F. Still 
further, as the solid materials are advanced out of the means M into the 
pump means P, they are again worked upon by and between the ring teeth and 
cutting blades of the disc D to still further reduce the material and 
render it freely pumpable and incapable of plugging and/or fouling the 
pump means. 
The prime mover E, as noted above, is preferably a simply electric motor 
structure mounted on the flange 40 of the journal plate J and is drivingly 
coupled with the axle pin or shaft 37 of the screw S. 
It is to be noted and understood that the details of construction 
illustrated in the drawings and described in the foregoing is but one 
embodiment of my invention and that in practice, many of the details of 
construction can be varied widely without in any way departing from the 
spirit of my invention. 
Having described only one typical preferred form and carrying out of my 
invention, I do not wish to be limited to the specific details herein set 
forth, but wish to reserve to myself any modifications and/or variations 
that may appear to those skilled in the art and which fall within the 
scope of the following claims: