US3456592A

US3456592A - Sewage chopper pump

Info

Publication number: US3456592A
Application number: US710314A
Authority: US
Inventors: Lloyd L Nelsen
Original assignee: PARMA WATER LIFTER CO
Current assignee: PARMA WATER LIFTER CO
Priority date: 1968-03-04
Filing date: 1968-03-04
Publication date: 1969-07-22
Anticipated expiration: 1986-07-22

Description

L. L. NELsEN July 22, 1969 SEWAGE CHOPPER PUMP 2 Sheets-Sheet l Filed March 4, 1968 mm. m

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United States Patent O M 3,456,592 SEWAGE CHPPER PUMP Lloyd L. Nelsen, Parma, Idaho, assignor to Parma Water Lifter Company, a corporation of Idaho Filed Mar. 4, 1968, Ser. No. 710,314 Int. Cl. F04d 1/14; B02c 21/00, 18/10 U.S. Cl. 103-111 10 Claims ABSTRACT F THE DISCLGSURE A combination centrifugal pump and cutter assembly for removing liquid slurries from an underground well. Cutter blades having spiral cutting edges cooperate with shear bars to chop pump clogging solids above the top axial inlet to the pump. The cutter blades are fastened to the drive shaft above the pump inlet and are vertically adjustable therewith relative to the shear bars from an above surface location on a mounting platform 'below which the drive shaft extends within a tubular casing.

This invention relates to nonclogging types of centrifugal pumps particularly adapted to the vertical displacement of solid contaminated liquids such as sewage.

In submerged pump installations with which the present invention is concerned, eflicient and rapid displacement of liquid requires the top mounting of the axial inlet for the pump about the vertical impeller drive shaft. However, a clogging problem presents itself since gravity enhanced concentrations of solids will enter the pump inlet and tend to clog the pump.

In an attempt to alleviate this problem, it has been proposed in Patent No. 2,714,354 to Farrand that horizontal rotary cutter blades be mounted on the vertical impeller drive shaft closely spaced above the intake opening in the pump housing with the blades extending radially beyond this intake opening by a substantial amount so as to chop or -comminute solids. Such an arrangement is not entirely satisfactory since lthe rotary cutter blades are not completely effective to prevent entry of pump clogging solids into the pump housing through the intake opening and do not prevent the concentration of solids adjacent the intake opening. Thus, the rotary cutter blades may even contribute to the overloading of the impeller drive shaft.

The foregoing inadequacy of the prior art in overcoming the pump clogging problem, is effectively eliminated by the arrangement of the present invention to provide a trouble-free, nonclogging submerged pump installation which may also be externally adjusted so as to maintain effective chopping action to prevent clogging of the pump.

In accordance with the present invention, a centrifugal pump unit suspended by a tubular casing through which the pump impeller drive shaft extends mounts a chopper blade assembly within the spider connecting the lower end of the tubular casing to the pump housing about the pump intake opening. The chopper assembly includes cutter blades which extend vertically a substantial distance between the spider assembly and the pump housing having radially outer, spiral cutting edges closely spaced inwardly from the outer periphery of the intake opening and cooperating with closely spaced, stationary shear bars mounted on posts which vertically space the spider assembly from the pump housing and interconnect the same with the pump housing. Ro-tation of the drive shaft with which the cutter blades rotate, is effective to cause axial upward displacement of pump clogging solids by the cutter blades, as the cutting edges shear and comminute the solids by cooperation with the shear bars. Thus, the chopper assembly prevents concentration of 3,456,592 Patented July 22, 1969 clogging solids in the vicinity of the pump intake opening to reduce loading of the chopper blades without any substantial impedance to the flow of nonclogging material into the intake opening. Furthermore, shearing of solids between the spiral cutting edges of the chopper blades and the shear bars occ-urs closely spaced radially inwardly of the intake opening periphery so that comminuted material may directly ow into the intake opening.

The radial distance of the spiral cutting edges and the cooperating shear bar surfaces vary in an axial direction, increasing downwardly by a small amount. Thus, when the spacing between the cutting edges and the shear bar surfaces increases because of wear, the cutter blades may be axially adjusted upwardly through the drive shaft in order to restore the proper spacing and thereby maintain the effectiveness of the chopper blade assembly. Such adjustment may be effected at the upper end of the drive shaft above the platform frame from which the pump assembly is suspended.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE l is a side section view showing the apparatus of the present invention in side elevation, in a typical installation.

FIGURE 2 is an enlarged top section view taken substantially through a plane indicated by section line 2-2 in FIGURE 1.

FIGURE 3 is an enlarged side sectional view taken substantially through a plane indicated by section line 3-3 in FIGURE 1.

FIGURE 4 is an enlarged partial sectional view taken substantially through a plane indicated by section line 4-4 in FIGURE 2.

FIGURE 5 is a top sectional view taken substantially through a plane indicated by section line 5 5 in FIG- URE 4.

FIGURE 6 is an enlarged partial sectional View taken substantially through a plane indicated by section line 6-6 in FIGURE 4.

FIGURE 7 is a perspective View of one of the shear bars associated with the apparatus of the present invention.

Referring now to the drawings in detail, FIGURE 1 illustrates the apparatus of the present invention generally denoted by reference numeral 10 adapted to be installed at a location for displacing a liquid slurry from a deep underground well or sump 12. The apparatus includes an above surface frame assembly 14 including a platform portion 16 overlying the sump from which a centrifugal pump device 18 is suspended by means of a tubular casing 20 interconnected with the pump device through a chopper assembly generally referred to by reference numeral 22. The pump device 18 when operated causes displacement of liquid from the body of liquid 24 within which it is submerged upwardly through an assembly of vertical discharge conduits 24 to an above surface location. The pump device is driven by means of an elongated impeller drive shaft 26 extending through the tubular casing 20 between the pump device 18 and a multisheaved pulley wheel 28 above the platform 16. The pulley 28 is connected by the endless drive belts 30 to a multisheaved drive pulley connected to the output shaft of an electric motor 32 secured to the frame assembly 14 and constituting the prime mover.

As more clearly seen in FIGURES 2 and 4, the centrifugal pump device includes a lower housing section 34 bolted to an upper housing section 36. The housing sections form a tangential outlet 38 connected by the transition conduit sections 40 to the assembly of vertical discharge conduits 24 aforementioned. The central opening 42 in the lower housing section 34 is closed by a plate 44 bolted to the housing section and mounting a thrust bearing assembly 46 receiving the lower end of the drive shaft 26 which may be formed from two or more shaft sections interconnected by internally threaded couplings 48. The drive shaft therefore extends into the pump housing through an intake opening 50 formed in the upper housing section 36. The housing sections enclose a plurality of radially extending impeller blades 52 having a hub portion 53 which is splined to the drive shaft 26. Rotation of the drive shaft by means of the motor 32 will therefore transmit rotation to the impeller blades causing tangential discharge of liquid entering the housing through the intake opening 50 from the tangential outlet 38.

The tubular casing 20 through which the drive shaft extends, includes two or more tubular sections 54. Adjacent ends of the tubular sections '4 are spaced apart by collar members 56 as shown in FIGURE 4 through which the drive shaft 26 extends and maintained in concentric relation to the tubular casing assembly. A coupling collar 58 threadedly engages the externally threaded adjacent end portions of the tubular sections 54 to make a liquid tight assembly. The upper externally threaded end of the uppermost tubular casing section 54 is threadedly received within the internally threaded lower end portion of a bearing member 60 having a mounting ange 62 secured by a plurality of fastener bolt assemblies 64 to the platform 16.

Spaced bearings

66 and 68 as shown in FIGURE 3, are supported on axially spaced thrust shoulders internally formed within the bearing member 60 in order to rotatably support a mounting sleeve 70 connected to the pulley 28 and the drive shaft 26 above the bearing member by means of the spline 72. The drive shaft is held in a vertically adjusted position relative to the sleeve 70 by means of an adjustment collar 74 threadedly engaging an upper threaded end portion 76 of the drive shaft to which the collar may be locked by means of the setscrew 78. It will be appreciated therefore, that the vertical position of the drive shaft assembly may be adjusted either upwardly or downwardly by loosening the setscrew 78 and axially advancing the adjustment collar 74 upwardly or downwardly. The lower end of the drive shaft on the other hand is slidably connected to the impeller blades as aforementioned so that it may be axially displaced relative thereto and relative to the tubular casing assembly from which the pump device 18 is suspended.

The lower end of the tubular casing assembly is connected to the hub portion 80 of a spider assembly having four spider arms 82 in the illustrated embodiment extending radially outwardly from the hub portion. The spider arms are secured by the fasteners 84 to a plate 86 having a central opening through which the drive shaft 26 extends. The spider assembly is vertically spaced by a substantial distance from the upper housing section by means of three posts 88 welded to an annular frame 90 having cutout openings 92 between the posts as more clearly seen in FIGURES 5 and 6. The annular frame 90 includes a top portion 94 to which the spider arms 82 and plate 86 are secured by the fasteners 84 and through which the drive shaft 26 extends. Tabs 96 extend radially outwardly from the annular frame 90 at its lower end in alignment with the posts 88 for securing the frame to the upper section 36 of the pump housing by means of the fasteners 98. The posts 88 are thereby positioned by the annular frame 90 in equal circumferentially spaced relation to each other on the upper housing section right at the periphery 100' of the intake opening 50. Each of the posts 88 is accordingly adapted to mount a shear bar 102 in proper position relative to the intake opening 50.

As more clearly seen in FIGURES 4, 6 and 7, each of the shear bars includes a leg portion 104 secured by a plurality of fasteners 106 to one side of a post S8. Fastener receiving apertures 108 are accordingly formed in the leg 104. The other leg portion of the shear bar rests against the side of post 88 positioned on the periphery 100 of the intake opening so as to be disposed on the inside of the intake opening at the periphery presenting an arcuate surface 110 closely spaced radially inwardly from the periphery of the intake opening. The arcuate surface has a center of curvature which lies on the rotational axis of the drive shaft 26. Furthermore, the thickness of the leg portion of the shear bar presenting the arcuate Surface 110 varies from a maximum at its upper end to a minimum at its lower end as shown in FIGURE 4. Accordingly, there is a slight increase in the radial distance of the arcuate surface 110 in a downward direction. This radial variation corresponds to a similar radial variation in the dimensions of the cutter blades 112 mounted on and projecting radially from the drive shaft 26.

The cutter blades 112 are equal in number to the shear bars 102 with which they cooperate to comminute solids. The cutter blades are interconnected by a central hub 114 secured in any suitable fashion as for example by the setscrew 116 to the drive shaft. The cutter blades are furthermore secured by the hub 114 to the drive shaft in angular positions aligned above the irnpeller blades 52 as more clearly seen in FIGURE 5. Each of the cutter blades is provided with a radially outer cutting edge 118 closely spaced by a constant amount from the arcuate surfaces 110 of the shear bars. The cutting edges accordingly vary in radial distance from the rotational axis of the drive shaft in accordance with the dimensional variation aforementioned in connection with the arcuate surfaces 110 relative to the rotational axis. Furthermore, the cutting edges 118 of the cutter blades are spiral shaped. By virtue of this spiral shape, solids are progressively sheared between the cutting edges and the arcuate surfaces 110 of the shear bars in response to rotation of the drive shaft. Also, rotation of the cutter blades tends to axially displace solids upwardly away from the intake opening 50 to thereby prevent concentration of solids and excessive loading of the drive shaft at the chopper assembly.

It will be appreciated, that the cutting action of the chopper assembly 22 will be most eiiicient for a given Spacing between the radially outer cutting edges 118 of the cutter blades 112 and the shear bars 102. This spacing may change because of wear. Therefore, in order to maintain maximum eiciency of the chopper assembly, optimum spacing between the cutter blades and the shear bars should be restored. This may be readily effected by vertical upward adjustment of the drive shaft 26 to which the cutter blades 112 are axially as well as rotationally secured. The vertical adjustment may be effected through the adjustment collar 74 as hereinbefore described.

The foregoing is considered as illustrative only of the prinicples of the invention. Further, since numerous modications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. In combination with a centrifugal pump submerged within a body of liquid contaminated with pump clogging solids having a housing provided with an axial intake opening, impeller blades and a vertically elongated drive shaft connected to the impeller blades and extending upwardly therefrom through the intake opening, means submerged within the body of liquid for preventing clogging of the pump comprising a spider assembly through which the drive shaft extends vertically spaced above the pump inlet, a plurality of shear bars xedly connected between the spider assembly and the housing of the pump and cutter blade means connected to the drive shaft between the spider assembly and the pump housing and having a spiral shape tending to upwardly displace the solids in response to rotation of the drive shaft, said cutter blade means having at least one radially outer cutting edge cooperating with the shear bars to comminute the solids approaching the intake opening through the spider assembly.

2. The combination of claim 1 wherein said cutter blade means has at least one radially outer cutting edge axially inclined to said shear bars and means for vertically adjusting the position of the drive shaft to vary the spacing between the cutting edge and the shear bars.

3. The combination of claim 2 including a mounting frame, a thrust bearing assembly mounted by the frame through which the drive shaft extends and a tubular casing interconnecting the spider and bearing assemblies in vertically Aspaced relation to each other, said drive shaft adjusting means being mounted above the thrust bearing assembly.

4. The combination of claim 3 including a plurality of posts xedly spacing the spider assembly from the pump housing radially outwardly of the pump intake opening, and means securing the shear bars to the posts radially spaced from the drive shaft by an increasing amount in a downward direction and by a constant amount from the cutting edge.

5. The combintion of claim 4 wherein the cutter blade means is mounted on the drive shaft in alignment with the impeller blades, said cutting edge being spiral shaped.

6. The combination of claim 5 wherein each of said shear bars includes a vertically elongated portion having an arcuate surface confronting the spiral cutting edge closely spaced radially inwardly of the periphery of the pump intake opening.

7. The combination of claim 1 including a plurality of posts fixedly spacing the spider assembly from the pump housing radially outwardly of the pump intake opening, and means securing the shear bars to the posts radially spaced from the drive shaft by an increasing amount in a downward direction and by a constant amount from the cutting edge.

8. The combination of claim 7 wherein each of said shear bears includes a vertically elongated portion having an arcuate surface confronting the cutting edge closely spaced radially inwardly of the periphery of the pump intake opening.

9. The combination of claim 1 wherein the cutter blade means is mounted on the drive shaft in alignment with the impeller blades, said cutting edge being spiral shaped.

10. The combination of claim 9 wherein each of said shear bars includes a vertically elongated portion having an arcuate surface confronting the spiral cutting edge closely spaced `radially inwardly of the periphery of the pump intake opening.

References Cited UNITED STATES PATENTS 942,297 12/1909 Van Ness 103--102 2,027,015 1/ 1936 Bell 241-255 2,371,681 3/1945 Durdin 10S- 111.1 2,714,354 8/1955 Farrand ID3-111.1 2,975,714 3/1961 Nechine 10B-111.1 3,155,046 11/1964 Vaughan 103-111.1

FOREIGN PATENTS I960,112 10/1949` France.

HENRY F. RADUAZO, Primary Examiner U.S. Cl. X.R.