US3726486A

US3726486A - Grinder pump

Info

Publication number: US3726486A
Application number: US00104681A
Authority: US
Inventors: A Smith; E Baggenstoss
Original assignee: ECOLOGY ENG AND Mfg Inc
Current assignee: ECOLOGY ENG AND Mfg Inc
Priority date: 1971-01-07
Filing date: 1971-01-07
Publication date: 1973-04-10
Anticipated expiration: 1990-04-10

Abstract

The functions of shredding and grinding have been separated from the pumping action of the grinding pump by utilizing two separate rotor sections attached to a common driving shaft. The first rotor contains a combination shearing plate and ripping bars which provide the functions of ripping the raw material and shredding this material into a discharge cavity. The end portions of the bars more efficiently rip the raw material without second rotor section contains a pumping member in the form of an impeller which is caused to rotate in a separate pumping cavity. The impeller causes a vacuum in the discharge cavity area which pulls the shredded material into the pumping cavity for discharge.

Description

United States Patent 1 Smith et a1.

[ GRINDER PUMP Assignee:

Filed:

Inventors: Arthur W. Smith, La Habra; Elmer Ecology Engineering and Manufactu'ring, Inc., Santee, Calif.

Jan. 7, 1971 App]. No.: 104,681

[52] US. Cl. ..241/46.11, 241/257 R [51] Int. Cl ..B02c 18/40 [58] Field of Search ..241/46 R, 46 A, 46 B,

' 241/46.1l,46.l7, 100.5, 257G [56] References Cited UNITED STATES PATENTS 2,857,109 10/1958 Haeussler ..24l/46.l1 2,902,227 9/1959 Higer ..241/257 R 3,013,736 12/1961 Pontis ..24l/46.11 2,063,996 12/1936 Gervais ..241/257 R X 2,484,509 10/1949 Hopkins ..241/257 R X 1 Apr. 10, 1973 2,824,702 2/1958 Lee ..241/100.5 X 2,853,249 9/1958 Wilder..... ....241/46.11 X 2,912,176 11/1959 J0rdan..... ..241/100.5 X 3,128,051 4/1964 Smith ..24l/46.l1

Primary Examiner-Granville Y. Custer,..1r. Attorney-Albert M. Herzig et al.

[57] ABSTRACT The functions of shredding and grinding have been separated from the pumping action of the grinding pump by utilizing two separate rotor sections attached to a common driving shaft. The first rotor contains a combination shearing plate and ripping bars which provide the fimctions of ripping the raw material and shredding this material into a discharge cavity. The end portions of the bars more efficiently rip the raw material without second rotor section contains a pumping member in the form of an impeller which is caused to rotate in a separate pumping cavity. The impeller causes a vacuum in the discharge cavity area which pulls the shredded material into the pumping cavity for discharge.

6Clalms ,4DrawingFlgu' res -Fluid Flow Fig.

Fig. 3.

Arthur W. Smith,

INVENTORS.

AGENT.

Elmer J. Boggensross;

PATENTEDAFR 1 0197s I sum 2 OF 2 Arthur W. Smith,

Elmer J. Boggenstoss,

INVENTORS..

' AGENT. I

GRINDER PUMP BACKGROUND OF THE INVENTION This invention relates to a pump and more particularly to a grinder pump of improved design. Pumps of this type are normally expected to handle a fluid flow of material containing all kinds of solid matter which must be collected and pumped through the system. These fluids generally contain solid material such as bone, sticks, glass, bottle caps, cans, nylon garments, rags, wood, and similar foreign matter that generally loads up and clogs conventional pumps.

The prior art discloses many patents covering the general field of garbage disposal grinders which operate on the principal of grinding the material until it is shredded and hence capable of being pumped by conventional pumping means. A significant improvement in the field of disposing of waste material is disclosed in the Wilder U.S. Pat. No. 2,853,249 which teaches the concept of using grinding jaws for grinding the material and in addition uses shearing edges for chopping the fibrous material into short lengths, which are readily passed into the disposal area for conventional pumping.

The problemin these prior art devices is that fibrous material wind around the rotor shaft and eventually clog the operation of the grinder pump. The Smith U.S.

Pat. No. 3,128,051 represents still an additional concept for preventing the grinder pump from being repeatedly clogged by the foreign material. Smith discloses specially placed orifices in the open face of the shearing plate for building up a back pressure which causes the incoming waste material to be forced against the grinding teeth and away from the rotating shaft.

The basic problems with the prior art devices however still persists since the ripping bars not only force the waste material against the cutting rings to provide the shearing action, but must also provide the pumping action for causing the comminuted material to be discharged from the grinder pump. The design of the ripping bars is therefore compromised since the propoer design for a pump is inconsistent with the required design for the ripping action of forcing the waste against the cutting ring.

The present invention solves these aforementioned problems by this new and novel design which now allows the ripping bar to perform'the functions of ripping only. Hence, the end portions of the bars have a preferred shape consistent with ripping the waste and which now prevent the waste material from jamming or loading the grinder pump. The pumping action is now achieved by a separate pumping impeller located on a separate rotor in a separate cavity and, hence, the pumping requirements of the grinding pump are improved. If required, a plurality of impellers may be used.

I SUMMARY OF THE INVENTION In this invention there is disclosed a stationary housmetrical, the" entire cutting ring can be removed,

rotated and then replaced thereby providing a new cutting edge facing the direction of the fluid flow since the shaft is arranged to rotate in a given direction. A driving shaft is located centrally within the housing and is arranged to be driven at one end by a conventional driving means, such as an electrical motor. A first rotor assembly comprising a plurality of ripping bars and a shearing plate is fixedly attached to the shaft with the ripping bars having a reduced diameter for rotation within the diameter of the defined cutting ring and in a direction that faces the fluid flow. The shearing plate portion has a diameter that is larger than the cutting ring and is located on the side away from the fluid flow and behind the cutting ring. The housing portion surrounding the shearing plate defines a discharge cavity which accepts the sludge that is produced by the action of the ripping bars and the shearing plate assembly. A second rotor assembly is comprised of a pumping impeller which is fixedly attached to the shaft and is located within a pumping cavity which is defined by the enclosing housing portion. The discharge cavity communicates with the pump cavity. The pumping action takes place solely within the pump cavity and as a function of the rotating pump impeller. In the preferred embodiment, a single impeller has been used. However, it is possible for large pumping operations to use a plurality of pumping stages each comprising a separate impeller fixedly attached to the shaft. The total number of impellers will be a function of the pumping action required.

Further objects and advantages of the present invention will be made more apparent as the description progresses.

Reference now being made to the accompanying drawings wherein;

FIG. 1 is a side evaluation of a grinder pump having a cut away portion which illustrates the preferred embodiment of the invention;

FIG. 2 is a section view of the pump taken along lines 2--2 of FIG. which more fully shows the combined shearing plate and ripping bar;

FIG. 3 is an enlarged perspective view-illustrating the tip portion of the cutting bar; and

. FIG. 4 is a front view of the pump impeller.

Referring now to FIG. 1, there is shown a preferred embodiment of the grinder pump which includes a driving force in the form of an electric motor 10 having an end casing 11 and a protruding shaft 12. Attached to the end casing 11 of motor 10 is a pump and grinder portion 13 consisting of an end casing 14, which is directly connected to the end casing 11 of the motor 10 and a casing 15 which is attached to casing 14 along the periphery thereof. Casings I4 and 15 define the housing encompassing the pump portion and the grinding portion of the invention. The open end of casing 15 is connected to the source of the waste fluid which is forced to pass through the pumping member. Depending on'the application, it is envisioned that either a flexible hose or permanent coupling will connect the housing 15 to the source of the waste fluid flow. The lo'ngitudinal dimension of casing 15 will therefore be a function only of the external coupling requirements which will connect the pump to the external system.

The casing 15 actually defines a housing which encompasses an internal diameter 16 through which the waste fluid passes. A cutting ring 17 comprising a plurality of stacked laminations, and having an external diameter that is slightly larger than the internal diameter of the casing 16 is press fit into the open end of the casing 15. A front view of the cutting ring 17 is also shown in FIG. 2. In the preferred embodiment, the cutting ring consists of a plurality of symmetrical cutting edges 18 which are formed by a plurality of offset half circles 19. The offset circles 19 on the cutting ring 17 provide the plurality of symmetrical cutting edges 18 that do not favor either a left-hand or right hand rotation of the motor shaft 12. Practical advantages of this system become more evident when it is realized that the grinding shaft 12 will rotate in a fixed direction throughout the normal use of the grinder pump and, hence, only one set of edges 18 will wear out. In the preferred embodiment casing and casing 14 are separate and are joined together along the periphery thereof, and hence to replace the cutting ring 17 it is only necessary to separate the casing 14 from the casing 15 without disassembling the complete grinder pump. The cutting ring 17 can then be removed by a conventional pressing tool. By simply rotating the cutting ring 17 around a diameter and then replacing the ring back into the casing 15 the unused cutting edge 18 will now face the direction of the waste fluid flow. In this manner the cutting ring is more easily removed and a new cutting edge is available without the necessity of replacing or buying new parts.

Located on the periphery of shaft 12 is a combined shearing plate and ripping bar assembly 20. The assembly 20 is either keyed or splined to the end of the shaft 12 so as to rotate as the shaft 12 rotates. The assembly 20 consists of a shearing plate 21 having a maximum diameter as at 22 that is greater than the internal diameter of either thecutting ring 17 or the internal casing as at 16. The minimum diameter of the shearing plate 21 is shown at 23 to have a diameter that is now less than the internal diameter of the cutting teeth porsociated with the moving fluid into the half circle 19 and against the cutting edges 18 of the cutting ring 17.

In the prior art devices the ripping bars 25 had to perform the functions of pumping liquid as well as the function of ripping the material. Hence, the design for the ripping bars 25 was compromised in order to achieve 'a good pumping action.

The square end design presently in use which is efficient for pumping is the primary cause forjamming and locking up of the pump mechanism. The fibrous or bulk material being forced between the square tip of the ripping bars 25 and the cutting edge 18 of the cutting ring 17 has the effect of stalling the driving motor 10 and causing a complete shutdown of the grinding pump operation.

In this invention, stalling or lock-up of the driving motor 10 is substantially eliminated by designing the end portion 26 of the ripping bar so as to have a rake angle with regard to the cutting edge 18 as shown in FIG. 3.

' As shown 'in FIG. 1, the waste fluid flow entersthe casing 15 through the reduced diameter end portion 16 and is directed to the ripping bars 25 which are fixedly attached to the shearing plate 21. The defined rake angle has the effect of pushing out or clearing any debris that may tend to jam between the face of the ripping bar 25 and the cutting ring 17. Since the pumping action is down stream of the grinding action, the fluid flow is being forced into the ripping bars 25 and the effect of the rake angle is to prevent debris from I jamming between the bars and the ring but instead forces the waste back into and against the direction of the fluid flow. This action tends to clear the area of debris that is not directly comminuted or otherwise forced through the cutting ring for discharge. This imtion 18 on the ring 17. In the preferred embodiment the diameter of the shearing plate 21 is formed with'a plurality of .cutting edges 24. The actual number of cutting edges will be a function of the capacity of the grinder pump and the speed of the rotation of the shaft 12.

However, in one embodiment four symmetrical cutting edges 24, each having the large diameter as shown at 22, was constructed and found satisfactory. The purpose of the cutting edges 24 is to shear all waste material forced through the half circles 19 into a fluid pulp.

Attached to the shearing plate 21 and preferably by welding or similar process are a plurality of ripping bars 25 and preferably one for each of the cutting edges 24 that are used on the shearing plate 23. In other words, if four cutting edges 24 are used on the shearing plate 21, then four ripping bars 25 are recommended. In the preferred embodiment the ripping bars 25 are offset from the cutting edges 24 so that each cutting edge 24 is substantially located between the ripping bars 25 as shown in FIG. 2.

In this invention as opposed to the prior art devices the ripping bars 25 perform the function of moving the waste into and against the cutting edges 18 on the cutting ring 17. There is no pumping action associated with the movement of the cutting bars 25 since the only purpose of the bars is to compress the waste mass asproved ripping bar can therefore use a smaller driving motor without fear of causing a stalling or lockup of the grinder pump due to foreign or other abrasive material being jammed between the ripping bars 25 of the cutting ring 17.

Since all the cutting and ripping action takes place along the periphery of the ripping bar 25, it has'been found desirable to construct the ripping bar 25 with a varying thickness that is smallest at the center where attachment is made to the driving shaft 12 and which gradually flares to a maximum at the end most portion asat 26 where contact is substantially made with the cutting ring 17. The purpose of this flared construction is to continually move the waste fluid from the center line of the pump out to the periphery where the grinding and shearing action takes place.

The action of the ripping bars 25 is to continuously move the waste fluid into the periphery so as to be forced against the cutting edges 18 of the cutting ring 17. The continuous grinding action will eventually comminute the waste material until it is free to pass through the half circles 19. The rotating shearing plate 21 has the effect of continually shearing or cutting the fibrous material that passes through the half circles 19. In the preferred embodiment there are four cutting edges on the shearing plate 21. In this manner all fibrous and bulk material is reduced in length to a pulp size that is capable of being pumped or moved by conventional pumping means. i

The discharge from the half circle 19 on the cutting ring 17 will fall into a discharge cavity 27 formed by the housing 14, which was described previously as being connected at one end to the end of casing l 1 and at the other end to casing 15. The discharge cavity 27 will be under a reduced pressure caused by the pumping action to be described.

The pumping action for the Grinder Pump is a result of using an impeller 28 which is attached to the shaft 12 by a spline or a key and which is caused to rotate in a pumping cavity 29 formed within housing 14.

The impeller 28 is more fully illustrated in FIG. 4 as consisting of four blades so arranged for rotation in a preferred direction. Because of the separation of the grinding and the shearing action from the pump action, it is now possible to construct the impeller 28 with substantially flat ends 31 in order to take advantage of the improved pumping action associated with this type of device. The impeller 28 may now be constructed and fabricated of plastic rubber or other types of resilient material as opposed to the prior art device which must construct their impeller of metal since the impeller also had to serve the function of a ripping bar.

As shown in FIG. 1, the discharge from the discharge cavity 27 is along the center-most portion of the pumping cavity 29. Due to the action of the impeller 28, the pulp material is pumped centrifugally out of a discharge port 32 where the material has now been reduced to nothing more than a slury or pulp.

Certain unobvious advantages are now possible by a direct result of separating the shearing and ripping actions from the pumping action. For example, it is now possible to add additional ripping and shearing stages between housing 14 and housing 15. Depending on the size and volume of material to be pulverized or comminuted, it is now possible to add a plurality of differentthickness of cutting rings 17. The first cutting stage can be made larger than the cutting ring for the second stage until the desired size pulp is obtained. The shearing plate for the first stage may have only one or two cutting teeth so as to permit longer and thicker fibers to be moved through the first stage. The second cutting stage may then have a thinner cutting ring 17 and more teeth on the shearing plate 21 so as to again reduce the size of the fibers of material passing through to the pumping member. Additional grinding and shearing stages would then be a function only of the external requirements using the grinder pump.

In view of the separate casings it is also possible to separate the casings 11 and M and insert additional pumping stages so as to obtain the benefits of a multiple stage pump having a plurality of impellers 28. In a similar fashion therefore it isnow possible to add additional pumping stages dictated only by the requirements of the ultimate user.

What is claimed is: I

1. A grinder pump defining a fluid flow path therethrough, comprising:

a stationary housing containing a reversible annular cutting ring having a diameter that is less than the inside diameter of said housing, said cutting ring having inwardly projecting cutting teeth shaped symmetrically relative to radii therethrough; a shaft located centrally within said housing; a combination of ripping bars and shearing plate fixedly attached to said shaft; the ripping bar portion having a reduced diameter for rotating within the inner diameter of said cutting ring;

the shearing plate being located on the downstream side of the cutting ring and having portions of a diameter larger than said cutting ring;

the housing portion surrounding the shearing plate defining a discharge cavity, and a separate pump member fixedly attached to said shaft and located within a pump cavity formed by the housing and having an inlet communicating with said discharge cavity adjacent said shaft;

the pump cavity accepting the discharge from said discharge cavity at said inlet and discharging or pumping the fluid flow at another point.

2. A grinder pump according to claim 1 in which said housing is comprised of a first part defining the fluid entry section at one end and which holds the cutting ring at the other end; and

a second part defining the discharge cavity and a section of the pumping cavity.

3. A grinder pump according to claim 1 in which each of said ripping bars has a thickness varying from a minimum at the shaft to a maximum at the radial extremity of the bar. I

4. A' grinder pump according to claim 1 in which each of said ripping bars projects into the fluid flow a varying amount ranging from a minimum at the shaft to a maximum at the periphery of said bar.

5. A grinder pump according to claim 1 in which said cutting ring is comprised of a plurality of identical laminations forming a stacked array.

6. A grinder pump defining a fluid flow path therethrough, comprising:

a stationary housing having an annular cutting ring therein, said cutting ring having inwardly projecting teeth, thereon;

combination ripping bar and shearing plate rotatably mounted in said housing for rotation about the axis of said cutting ring and having generally radially extending ripping bars rotatable radially inwardly of said cutting ring and having generally planar outer axially elongated end edge surfaces extending generally tangent to said axis, in a circumferential direction, and arranged to define a space between said surfaces and the inner ends of said teeth that converges axially in the direction of fluid flow whereby to minimize clogging of material in the spaces between said teeth.

a :r a: a

Claims

1. A grinder pump defining a fluid flow path therethrough, comprising: a stationary housing containing a reversible annular cutting ring having a diameter that is less than the inside diameter of said housing, said cutting ring having inwardly projecting cutting teeth shaped symmetrically relative to radii therethrough; a shaft located centrally within said housing; a combination of ripping bars and shearing plate fixedly attached to said shaft; the ripping bar portion having a reduced diameter for rotating within the inner diameter of said cutting ring; the shearing plate being located on the downstream side of the cutting ring and having portions of a diameter larger than said cutting ring; the housing portion surrounding the shearing plate defining a discharge cavity, and a separate pump member fixedly attached to said shaft and located within a pump cavity formed by the housing and having an inlet communicating with said discharge cavity adjacent said shaft; the pump cavity accepting the discharge from said discharge cavity at said inlet and discharging or pumping the fluid flow at another point.

2. A grinder pump according to claim 1 in which said housing is comprised of a first part defining the fluid entry section at one end and which holds the cutting ring at the other end; and a second part defining the discharge cavity and a section of the pumping cavity.

3. A grinder pump according to claim 1 in which each of said ripping bars has a thickness varying from a minimum at the shaft to a maximum at the radial extremity of the bar.

4. A grinder pump according to claim 1 in which each of said ripping bars projects into the fluid flow a varying amount ranging from a minimum at the shaft to a maximum at the periphery of said bar.

6. A grinder pump defining a fluid flow path therethrough, comprising: a stationary housing having an annular cutting ring therein, said cutting ring having inwardly projecting teeth, thereon; a combination ripping bar and shearing plate rotatably mounted in said housing for rotation about the axis of said cutting riNg and having generally radially extending ripping bars rotatable radially inwardly of said cutting ring and having generally planar outer axially elongated end edge surfaces extending generally tangent to said axis, in a circumferential direction, and arranged to define a space between said surfaces and the inner ends of said teeth that converges axially in the direction of fluid flow whereby to minimize clogging of material in the spaces between said teeth.