US3463088A - Pump - Google Patents

Description

E. UMBRICHT Aug. 26, 1969 PUMP Original Filed Oct. z'

4 Sheets-Sheet 1 Aug. 26, 1969 Original Filed Oct. 6, 1961 El UMBRICHT PUMP 4 Sheets-Sheet 2 Aug. 26, 1969 PUMP original Filed ont. s. 1961 E. UMBRICHT 4 Sheets-Sheet 5 35 O C .if

Aug. 26, 1969 E. UMBRICHT 3,463,088

PUMP

Original Filed Oct. 1961 4 Sheets-Sheet 4 IN VEN TOR. .FH/l. UNEF/(Hf United States Patent O 3,463,088 PUMP Emil Umbricht, Northviile, Mich., assigner to Ajem Laboratories, Inc., Livonia, Mich. Continuation of application Ser. No. 143,355, Get. 6, 1961. This application Oct. 22, 1964, Ser. No. 407,272 Int. Cl. F0411 1/04, 29/22, 29/42 U.S. Cl. S-103 10 Claims This is a continuation of my copendng application Ser. No. 143,355, led Oct. 6, 1961, now abandoned.

This invention relates to a pump for pumping and raising the pressure of liquids, more particularly to a rotary impeller centrifugal pump.

In prior Patents No. 2,873,685 and No. 2,890,660, I disclosed pumps for moving liquids for power washers and the like. Pumps embodying the patented invention have proven highly successful and have done yeoman service in power washers for the metal industries and in air washers and the like. With increasing pressures for eifectiveness and eiiiciency of such washing equipment, however, a need has developed for higher pressures and greater volumes and velocities in pumped liquids. The present invention meets this need by a pump capable of operating at low or very high rotation rates to produce any of a Wide variety of velocities and pressures.

There also has developed a need for such pumps in connection with wet blasting of manufactured parts with abrasive. slurries, suspended shot particles or other solid particle suspensions, which tend to carry into pumps substantial amounts of suspended solids which by getting into close clearances on rotating or sliding parts have caused rapid wear and consequent loss of efficiency which has required frequent replacement. My present invention meets this problem by opening of such clearances to an extent where the suspended solids can pass through without grinding between the relatively moving surfaces. This should produce at the outset the serious impairment of operation which had resulted from wear and abrasion of the known pumps; but surprisingly I have found that, by relatively simple and inexpensive changes in design, I have actually improved efiiciency and flexibility of operation and adaptability to different conditions of use. By my invention I can handle liquids, containing substantial amounts of suspended solids.

By making the impeller with passages of uniform cross section from the inlet near the center to the periphery, the liquid therein is put under pressure at the periphery by the centrifugal force developed by rotation of the inipeller and by camming of the liquid outward by the convex face of the impeller blades. Because the enlarging circumference at greater radii would ordinarily result in a widening channel between impeller blades from center to periphery, the uniform cross-section of the channel is attained by widening the partitions instead of the spaces between. This results in the periphery having jets from the ends of such passages separated by the broad ends of the partitions. As the high speed rotation develops high pressure in the liquid these jets emerge into and sweep the clearance space at the periphery toward the outlet. In this space the jets pass through liquid which has leaked through the relatively wide clearances between the impeller and the housing and accelerates it by jet action and draws it along into the outlet duct.

By Bernoullis principle this acceleration results in a reduced pressure around these jets at the periphery of the impeller which allows it to draw liquid from the lower pressure near the inlet throat and avoids leakage out through the housing and center seals.

To 'further control leakage at the center and climbing of liquid on the rotating drive shaft, I also use a projecting flange as a slinger to throw oit any such climbing ICC liquid, and above it a partition or batiie so that any liquid reaching this flange is thrown off by centrifugal force and is prevented from going higher by the partition or baffle.

In spite of the reduced pressure in the leakage liquid being accelerated around the jets, the liquid in the jets is at relatively high pressure and consequently when the zone of acceleration is passed, the pressure in the delivery conduit is relatively high. This pressure and the velocity and volume of the liquid output is of course dependent upon speed of rotation of the impeller, and it is an advantage attainable in pumps embodying my invention that almost any desired pressure and capacity can be attained by use of a driving motor of the required speed and power.

Whereas in prior centrifugal pumps it has been unusual to have a housing with a rotor having impeller vanes to create a rotary flow in the housing, in my pump shown herein it will be seen that the impeller is an enclosed assembly having spiral channels therethrough rom the center to the periphery which are open at their ends but enclosed between.

Because there are no packed seals such a pump operates with very little friction and can advantageously be operated immersed in the reservoir of liquid to be pumped. Closer clearances may be used e.g., .003 to .008 where it is found that these do not present problems of grinding or jamming with suspended solids (and even smaller clearances when suspended particles are not concerned), but larger clearances can be used.

Because the channels through the impeller are of constant cross section, the tiow through the impeller is more controlled, the velocity and pressure are more etlciently developed and there is less wear on the impeller from suspended solids in the iiow. Also because the partitions between the channels are much thicker through most of their length, this impeller is stronger and more rugged and able to stand more wear.

The transition piece between the flatsided outlet from the cylindrical or volute interior of the impeller housing and the round bore of the delivery pipe has proven to be surprisingly important. This transition piece, designed as shown, results in smooth flow substantially without turbulence which ensures against added loss in the flow of liquid which would reduce efficiency.

The use of scroll type impeller blades" or partitions as shown here provides for controlling the forward motion of liquid when released from the impeller, assures a positive increased pressure and gives better control of wear.

In the accompanying drawings, I have shown and have described below, a preferred embodiment of the invention. I have also suggested herein certain modications and alternatives but it should be understood that these are not intended to be exchaustive but rather to give a fuller understanding of the invention and its application in practical use, so that others will be enabled to modify and alter its embodiment and to adapt it as may be best for each particular use.

In these drawings,

FIGURE 1 is a view in axial cross-section of a pump embodying the invention;

FIGURE 2 is an isometric exploded view in axial section of the pump shown in FIGURE l;

FIGURE 3 is a plan view of the impeller housing and transition mouth;

FIGURE 4 is a schematic plan view of the arrangement of the impeller blades or partitions looking down on the impeller with its top plate removed but shown in phantom -by broken lines;

FIGURE 5 is an end View of the transition mouth taken from the right of FIGURE 3;

FIGURE 6 is a top plan view of the top plate shown in FIGURE 1 looking upward, but with the drive shaft and bearings removed;

FIGURE 7 is a sectional view taken on line 6-6 of FIGURE 1 looking down, but with the shaft and bearings removed;

FIGURE 8 is enlarged view in axial cross-section of a portion of the impeller and impeller housing.

Referring now to these drawings, impeller rotor 10 is comprised of a top plate 12 and a bottom plate 14 and a series of equally spaced spiral blades 16 arranged as shown in FIGURE 4 and welded to said plates respectively. An intake throat 18 consists of a tubular piece 17 with a narrow flange welded to the bottom plate 14 which has a hole corresponding to the bore of the tube, thus making the throat continuous into the interior of the rotor 10. A similar but smaller tube welded to the top plate 12 around a corresponding opening in the plate makes a mounting and drive collar 20, the bore of which is tted to the end of drive shaft 22 and groove to form a keyway 24.

A housing for the impeller is made up of a bottom plate 26 having welded thereto an outer peripheral wall 28 having the form shown in FIGURES 2 and 3, and provided with a flange 29. It will be seen that this outer wall is spiral for most of its periphery with gradually increasing radius, but at one side it becomes tangential extending substantially along a tangent to the transition mouthpiece 32. A flange 34 on the mouthpiece is provided with bolt holes 35 as Shown in FIGURE 5 for securing it to a pressure conduit (not shown). A partition point 36 Shown in phantom lines in FIGURE 3 comes substantially to the circle of the impeller rotor and diverges therefrom at rst on a shorter radius from a center displaced toward the wall and then on progressively greater radii and from centers displaced respectively less and less from the center of the rotor. A top plate 38 lits onto the top of the impeller housing except near the outlet port where the bolt holes come so close to the edge (because of the shorter radius) that the top plate is extruded out over the edge of the wall iiush with its outer periphery. Substantial clearances are provided above and below the rotor, e.g., for a 500 gallon per minute pump operating at about 3000 r.p.m. the clearance may be LH6 below and :if/16 above; for a 1200 r.p.m. pump 7/153, below and above. The plate 3S is bolted to flange 29. An intake port and lower seal hub 19 is welded to bottom plate 26 to surround a central hole therein. A lower inlet, seal 41 is seated with a press t in said lower seal hub 19.

An upper hub 40 is welded to top plate 3S to surround a central hole corresponding to that in plate 26 and has an inwardly directed annular flange 43 closely fitting the third step of the stepped drive shaft 22 with a clearance only sufficient to avoid friction and allow suspended solids to pass without grinding or jamming. An upper seal 42. is engaged in the hub 40 by a press fit and acts as a seal and bearing for the shaft 22, or more particularly, for drive collar 2G which is bolted onto shaft 22.

The seal bearings 41 and 42 and the corresponding journals (i.e., drive collar and intake collar 17) have clearances which are suicient to allow potentially abrasive or potentially jamming suspended particles to freely ow therethrough. As the drive collar 20 is a tight t pressed home by the nut on the end of shaft 22, no leakage can occur there from the interior of the rotor. The relatively loose iit of the seal 42 on the shaft, however, would permit leakage of liquid upward from the space between the rotor 10 and the top plate 38 of the housing. Such leakage is minimized by two important factors in the structure shown. 1) the high speed rotation of rotor 10 tends to throw all liquid in the space above the rotor outward by centrifugal action and thus to avoid pressure at the center which would induce flow through such clearance, (2) the yflange 43 on hub 40 extending over the upper edge of mounting collar 20 requires any leakage flow which can reach the center notwithstanding the centrifugal action must again flow inward against centrifugal action over the end of collar 20 and then up through the clearance between hub 40 and shaft 22.

Such liquid, if any, as does escape these seals can only climb to the bottom of the fourth step where the surface 45 normal to the axis of the shaft serves by its centrifugal action as a slinger to throw off horizontally any liquid which reaches it.

The top plate 38 of the rotor housing is part of any integral pedestal structure which also comprises an upper pedestal plate 44, a tubular column 46 welded to plates 3S and 44 and an annular shelf 48 welded to the inside of the tubular column 46 just above the slinger washer 50. This washer 50 is held in position by a ring 52 having set screws 53, the ring being pushed down against the washer 50, clamping the latter against the shoulder between the fourth and fifth steps of shaft 22 and then secured in such position by set screws 53. ' Ports 54 and 55 are provided through the wall of tubular pedestal column 46.

The slinger washer can be of any material of considerable strength, but is usually of steel or brass or a plastic, eg., synthetic rubber. Its function is to throw off by centrifugal force any liquid which tends to climb up the shaft. Shelf 43 has a central opening just large enough to permit insertion of the shaft with the washer 50 in position on it and is positioned above the washer so that any liquid thrown off by the washer will go under the shelf 48. Advantageously, the liquid level in the reservoir is between the ports 54 and 55 and below the level of shelf 48.

The upper plate 44 of the pedestal assembly, lower bearing ring 60, and lower bearing 62, are secured by bolts (not shown) extending through the holes 61 into threaded holes 61. Notches, or ports 55 are cut under the holes 61 to allow the ends of the bolts (not shown) to project below plate 44. Upper plate 44 and bottom plate 57 of a shaft guard are bolted through holes 58 in plates 44 and 57 into threaded holes 58 in lower bearing ring 60. Bottom plate 57 is bolted to the top plate of the reservoir in which the pump is submerged. The bearing shown diagrammatically at 62 clamped by ring 60 is thus above the liquid level and provides secure mounting for shaft 22.

A shaft guard housing 64 also serves as support for the upper bearing indicated diagrammatically at 66. At the top of shaft 22 is a sheave for a multiple V-belt drive connection to a drive motor (not shown), or even the motor iteself if the support is made sufficiently rigid and strong. This shaft guard housing-support consists of a steel plate bent as shown in FIGURE 7 to form three sides and two flanges 65 at the front, leaving an access opening. A bar 74 of angle iron extends across the front welded to the flanges 65 and anges 76 are formed at the tops of the other sides by bending over the plate 64 or by welding thereto. A top plate 68 is secured to the flanges 74 and 76.

A bushing or sleeve 70 fitted over the upper end of shaft 22 after the bearing 66 is in place and the nut 72 threaded onto the shaft 22 clamp the inner race of bearing 66 on the shaft.

The transition mouthpiece 32 takes the liquid output from the rectangular opening from the pump housing and delivers it into a pipe of circular cross section. This is designed so that it has substantially constant cross-sectional area.

Pumps made embodying the invention are highly adaptable to varying requirements, for example pumps may be designed for capacities of a few gallons per minute or for thousands of gallons per minute. Pumps may be designed to run at a few hundred r.p.m. or at thousands of r.p.m. With a given pump the pressure and volume capacity are increased by increasing r.p.m. Thus with the pump shown in the drawings, in one size it delivers 1200 gallons per minute at pounds per square inch pressure; in a smaller size it is rated at 500 gpm. Both pumps are rated to operate at 1800 to 4800 r.p.m. and can be operated at even higher speeds when greater pressure or output volume rate is required. A somewhat larger pump operated at 1775 r.p.m. by a 150 horsepower electric motor delivered 1400 gal. per minute at 140 pounds per square inch. The following is a summary of performance on one example with a pump rated at 500 gal. per minute but operating to deliver 600 gal. per minute, the structure as shown in the accompanying drawings and using a 5 H.P. 1760 r.p.m. electric motor with a 5.4" pitch diameter sheave on the pump and a 11.0 pitch diameter sheave on the motor, the pump operates at 3550 r.p.m. and gives an efficiency of 75% and output pressure of 114 pounds per square inch with 54 H.P. actual load. With the same apparatus, excepting for substitution of a 6.0 pitch diameter sheave on the pump, the speed of the pump is reduced to 3220 r.p.m. and the efficiency is slightly reduced to 73.5%, the output pressure is more significantly reduced to 87 pounds per square inch with 43 H.P. actual load.

With a further change by substituting an 8.6 pitch diameter sheave on the motor with the 6 sheave remaining on the pump) the speed of operation is reduced to 2550 r.p.m., the efficiency remains substantially the same as before, but the output pressure is reduced to about 50 pounds per square inch and the H.P. to 22.

These pumps under any of these conditions operate well from 300-600 gah/min. output. With output below this range the efficiency drops olf rapidly, although pressure and H.P. may remain about the same. This is in contrast with older pumps not having the uniform crosssection transition mouthpiece. With such older designs, the maximum efficiency and pressure would have been reached under the same conditions with 300 gal./ min. How and both efficiency and pressure would have seriously declined by 500 gaL/min. output, and beyond that, would drop off too rapidly to be considered practicable. Reductions of ow below 200 gal./min., likewise produced progressive decline in efficiency, output pressure.

Pressures may be raised even higher by operating this pump above 3550 r.p.m. With closer clearances in liquid seals and more precise machining of interior conformations, one can improve the operating characteristics over those listed above, but it is an important advantage of such pumps that it can perform satisfactorily without such extra care and can accommodate suspended solids and even abrasives which would quickly destroy ordinary pumps. The ability to retain high efliciency with change of r.p.m. adapts these pumps for wide control of capacity and pressure.

In summary, the pump described has a number of unique features:

Its ability to operate efficiently and for relatively long times when immersed in liquids containing solids in suspension. Its elimination of tight, friction-producing seals and its use instead of liquid seals above and below the impeller rotor. Its relatively high pressure developed with high liquid output. Its ease of assembly and disassembly. Its use of impeller blades of increasing cross section toward the periphery to give improved control of flow of liquid, and development of pressure and to control wear of the impeller. Its ease of installation with pre-alignment in the housing and bearing supports with accurate uniform clearance in the liquid seals above and below the impeller. Its transition throat designed for smooth flow with uniform cross sectional area.

I claim:

1. A transition mouthpiece for a centrifugal pump which comprises a rectangular intake opening adapted to fit the rectangular tangential outlet of a rotor housing, a round outlet opening, transition walls between said intake opening and said outlet opening being formed to maintain uniform cross sectional area and smooth flow path from end to end.

2. A centrifugal pump adapted for handling liquid suspensions and contaminated liquids with low wear, long life and high efficiency comprising la 4scroll body, a substantially vertical rotatable shaft, a shaft support, drive means for said shaft, a scroll-support assembly suspended from said shaft support, a seal centered in the bottom face of said scroll-support assembly through which said rotatable shaft extends, a pump scroll suspended from the scroll-support assembly having a central intake pipe in the lower surface, said intake pipe having a seal, an impeller assembly having parallel circular plates with a plurality of backward sloping vanes extending between them and an upper central hub connected to the end of said rotatable shaft and a lower central hub fitted into said central intake pipe whereby to receive fluid therefrom, said impeller vanes commencing at the circumference of said lower hub and shaped to provide constant cross-section at all points along the path of liquid ow between the vanes to the outer circumference of the impeller assembly, said seals having sufficient clearance to allow substantially free passage of particulate suspended matter, said rotatable shaft having an abrupt shoulder near the scroll-support assembly that acts as a primary slinger of liquid if any escapes past the upper impeller seal, a secondary slinger connected higher on the rotatable shaft, said scroll support having escape holes in its wall opposite said primary slinger, a stationary splash deection shelf located in the scroll support assembly close above the secondary slinger, said scroll support also having holes located in its wall above the stationary shelf.

3. A transition mouthpiece as disclosed in claim 1 wherein said transition walls further comprise four isosceles triangular portions whose bases respectively abut each side of said rectangular intake opening, whise apices abut the circumference of sai-d outlet opening at intervals, and whose linear sides are jointed by convex surfaces.

4. A centrifugal pump adapted for handling liquid suspensions and contaminated liquids with low wear, long life, and high efiiciency comprising a rotatable shaft, a shaft support means, drive means for said shaft, a scrollsupport assembly suspended from said shaft support means, a seal in the bottom face of said scroll-support assembly through which said rotatable shaft extends, a pump scroll suspended from the scroll-support assembly having a central intake pipe having a seal, an impeller assembly having parallel circular plates with a plurality of vanes extending therebetween and an upper central hub connected to the end of said rotatable shaft and a lower central intake hub fitted into said central intake pipe whereby to receive fluid therefrom, said seals having just sufficient clearance to allow substantially free passage of particulate suspended matter.

5. A centrifugal pump adapted for handling liquid suspensions and contaminated liquids with low wear, long life, and high efficiency comprising a rotatable shaft, -a shaft support means, drive means for said shaft, a scrollsupport assembly suspended from said shaft support means, a pump `scroll suspended from the scroll-support assembly, an impeller assembly having parallel circular plates with a plurality of vanes extending therebetween and an upper central hub connected to the end of said rotatable shaft, central intake conduit means for introducing said liquid suspension into the center of said impeller assembly, seal means with just sufficient clearances to allow substantially free passage of particulate suspended matter for substantially sealing all central openings into said pump scroll other than the intake opening of said conduit means.

6. A centrifugal pump as defined in claim 2 which further comprises a transition mouthpiece comprising a rectangular intake opening adapted to fit the rectangular tangential outlet of a rotor housing and a round outlet opening, transition walls between said intake opening and said outlet opening being formed to maintain a uniform cross sectional area and a smooth flow path from end to end.

7. A centrifugal pump adapted for handling liquid suspensions of particulate matter with low wear, long life, and high efficiency, comprising a pump housing, an enclosed impeller rotatable in said housing, a liquid suspension discharge outlet leading from the peripheral portion of said housing, a rotatable shaft carrying `said impeller mounted to one end and extending out an axial opening of said housing, said impeller having an axial inlet with external access through an axial opening ofthe pump hous ing, seal means for sealing the axial clearances between the housing and the shaft-and-impeller assembly, said seal means having clearances at least 0.003 inch wide which are just sufficient to allow substantially free passage of particulate suspended matter, said shaft-and-impeller assembly being so constructed and mounted relative to the housing as to prevent significant relative displacement thereby to maintain sucient clearances at all times.

8. A pump as defined in claim 7 in which said impeller further includes a central intake hub mounted around the axial inlet, said hub extending out through a corresponding axial opening of said pump housing, thereby forming an axial clearance between said hub and said housing for said seal means.

9. A pump as deiined in claim 8 in which said hub is mounted on said impeller opposite from the rotatable shaft and extends through a separate axial opening in said housing, thereby forming a further axial clearance between said housing and said shaft-and-irnpeller assembly for said seal means.

10. A pump as defined in claim 8 in which said impeller further includes a plurality of backward sloping vanes 30 shaped to provide a substantially constant cross-sectional area for liquid passage between said vanes within said impeller.

References Cited UNITED STATES PATENTS 2,190,670 2/1940 Mann 103-103 2,179,730 11/1939 Ruthman 103-87 2,165,808 6/1939 Murphy 103-1 15 2,006,727 6/1935 Ardrey 103-103 3,070,026 12/1962 Lung 103-108 3,048,384 8/1962 Sweeney et al. 1,037,243 9/1912 Guy 103-112 885,108 4/1908 Trent 103-115 1,986,836 1/1935 MaeNeille 103-115 1,988,875 l/l935 Saborio 103-115 2,341,871 2/1944 Kerrer. 2,954,739 10/1960 Lung 103-115 2,906,208 9/1959 White 103--115 2,890,660 6/1959 Umbricht 103-103 2,281,682 5/1942 England.

FOREIGN PATENTS 809,758 8/1951 Germany.

247,161 2/ 1926 Great Britain.

832,549 2/1952 Germany.

927,821 6/1955 Germany.

HENRY F. RADUAZO, Primary Examiner U.s. C1. x.R.

Claims (1)

1. 2. A CENTRIFUGAL PUMP ADAPTED FOR HANDLING LIQUID SUSPENSIONS AND CONTAMINATED LIQUIDS WITH LOW WEAR, LONG LIFE AND HIGH EFFICIENCY COMPRISING A SCROLL BODY, A SUBSTANTIALLY VERTICAL ROTATABLE SHAFT, A SHAFT SUPPORT, DRIVE MEANS FOR SAID SHAFT, A SCROLL-SUPPORT ASSEMBLY SUSPENDED FROM SAID SHAFT SUPPORT, A SEAL CENTERED IN THE BOTTOM FACE OF SAID SCROLL-SUPPORT ASSEMBLY THROUGH WHICH SAID ROTATABLE SHAFT EXTENDS, A PUMP SCROLL SUSPENDED FROM THE SCROLL-SUPPORT ASSEMBLY HAVING A CENTRAL INTAKE PIPE IN THE LOWER SURFACE, SAID INTAKE PIPE HAVING A SEAL, AN IMPELLER ASSEMBLY HAVING PARALLEL CIRCULAR PLATES WITH A PLURALITY OF BACKWARD SLOPING VANES EXTENDING BETWEEN THEM AND AN UPPER CENTRAL HUB CONNECTED TO THE END OF SAID ROTATABLE SHAFT AND A LOWER CENTRAL HUB FITTED INTO SAID CENTRAL INTAKE PIPE WHEREBY TO RECEIVE FLUID THEREFROM, SAID IMPELLER VANES COMMENCING AT THE CIRCUMFERENCE OF SAID LOWER HUB AND SHAPED TO PROVIDE CONSTANT CROSS-SECTION AT ALL POINTS ALONG THE PATH OF LIQUID FLOW BETWEEN THE VANES TO THE OUTER CIRCUMFERENCE OF THE IMPELLER ASSEMBLY, SAID SEALS HAVING SUFFICIENT CLEARANCE TO ALLOW SUBSTANTIALLY

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