US2907278A - Impeller for centrifugal pump - Google Patents

Description

Oct. 6, 1959 R P EMERICK 2,907,278

IMPELLER FOR CENTRIFUGAL PUMP Filed Jan. 13, 1958 INVENTOR. fi Ti J BY RAYmouo P. EMERIcK E A *5 FM 4' M A-r ran M ay United StatesPatcnt 2,907,278 IMPELLER FOR CENTRIFUGAL PUMP Raymond P. Emerick, 'Mou'nt-Cle'mens, Mich. Application January 13, 1-958, Serial No. 708,525 4Clainis. (Cl. 103*103) This inventionrelates to centrifugal pumps and more particularly to a novel impeller construction thereof. -More particularly the presentinvention is directed tothe shape and curvature of the .impeller vanes and their relationship. V a

The present invention is particularly adaptable tolarge centrifugal pumps such as might-be used in dredging and pumping such as the pumping of water or oil or conglomerated mixtures thereof which might include sand, clay, gravel or rock. Heretofore centrifugal pumps in their operation have been accompanied with hammering resulting in loss of power andefliciency. This hammering is caused by the sudden release-f pressureof vacuum areas produced by velocity changes in the pumped material at different points along the radial and circumferential spaced fluid passages of the pump impeller.

The velocity flow of pumped material at different points within a fluid passage is directly dependent upon the initial velocity of the fluid pumped, the shape of the vanes and upon centrifugal force.

If the velocity of the pumped material is greater at the point of discharge of the fluid channels than at the intake thereof or at intermediate points, an irregularity of flow develops which intermittently produces low pressure or vacuum areas.

Another cause of hammering is:the sudden pilingup of pumped aggregate within the fluid passages 'caused'by temporary reduced velocity at the dischar'ge .end of the vanes, such as results with conventional circular curved vanes. It has been found with circular vanes that there is an excessive frictional force developed due to the sudden change in direction of the vanes tending to restrict .and reduce the velocity of the .pumpedmixture.

' When the initial velocity is not maintained, the suction pressure at the intake of the fluid conducting passage is irregular. These irregularities produce variations in fluid throughout the fluid channels.

With reference to my earlier U'.-S. Patent, 2,266,180, dated December 16, 1941, .relatin'g'to an Impeller For Centrifugal Pumps, I sought toovercome this hammering and to a great extent did so o'vercorne same by provi'd ing vanes which began with straight line portions and which terminated in portions of increasing radii.

It is the object of thepresen-t invention to provide a substantial improvement over my previous patented construction by a novel formation of the vanes with respect to each other whereby the inner ends of each of the vanes is defined by a straight line portion which extends at an acute angle and towards an intermediate portion of an adjacent vane thus providing an inlet passage between vanes which has portions of decreasing cross sectional area defining a venturi opening intermediate the length of the passage.

The purpose of the venturi construction is to provide an increase in the initial velocity of the material pumped which increased velocity is maintained as the material moves through the outlet portions of the passages to the periphery of the impeller.-

It is the further object of the present'invention to thereby provide with said "venturi construction a substantial increase in the efliciencyof the pum over existing pumps.

These ando'ther objects willvbeaseen 'fromthe following specification and claims in conjunction with the appended drawing in which:

Fig. 1 is a schematic side elevationalview of a centrifugal pump.

Fig. 2 is an end elevational View thereof.

Fig. 3 is a fragment-aryzsection-on :anenlarged scale taken on line 33 of 'FigL-l- Fig. 4 is a left side elevationalviewof the impeller shown in Fig. 3, showing thecasing fragmentarily.

It will be understood that the abovedrawing illustrates merely .a preferred embodiment of the invention and that other embodiments are contemplated within the scope of the claims hereafter-set forth.

Referring to the drawing, a centrifugal pump is indicated including casing :11 .having axially on one side thereof the projecting hubl12' with internal bushing 13 adaptedito receivetherethrough the end of power driven shaft 14 which extends into :the interior of said casing. Any suitable means such as ..the.motor-15.or other drive mechanism may be employed for driving shaft 14 as diagrammatically indicated in Fig. 2.

The i-llustrativemotor i's mouhted at 16 upon block "17 on base 18, uponwhichis also :mounted and secured casing 11.

As shown-inFigs. 1 and -3 theopposite side of said casing has a :circular enlarged opening 19 normally closed by cover '20, secured to.the casing by a series of spaced fasteners 21. Plate20include'sthe central axial flange 22 which defines-with saidqplat'ethefluid intake 23 adapted toreceiveth'e-end 'ofia-conduit or other pipe for delivering fluid or mixtures totheyinterior :chamber 40 of said casing. a

The casing also includes a conventional tangential outlet 24 adjacent base 18 which defines the fluid outlet 25 through which the pumped mixture is discharged.

A unitary'impeller generally designated at 27 is loosely positioned within casing 11 and ii'rcludesmet-allic disc 28 whose centr'al'hub '29 is apertured 'to axially receive the end of driveshaft 14 which is keyed thereto at 3.0.

There is provided upon one side of disc .28 defining the open impeller, a seriesof. spirally spaced laterally directed vanes 31 of uniform width. "These are spaced inwardly of the inlet siderof casing The inner ends of the vanes are respectively spaced outwardly of the center of disc 28 as defined by the imaginary circle 33 shown in dotted linesto thereby provide said impeller the axial inlet 32 in direct communication with fluid intake 23 in the casing.

The inner ends of said vanes furthermore define with respect to adjacent vanes a series .of spaced radial inlets to the passages 37.

The important part of the present construction lies in the shape of vane's"'31. "Each of these v anes at its inner ends includes the straight wall portion"34 which extends a distance outwardly approximately /3 the total radial distance to the perimeter of the disc. I have found, however, that the length of the straight line portion may be varied from between 15 percent to 60 percent of the radial distance from the beginning of the vane to said perimeter.

In the present preferred embodiment of the invention, the straight line portions 34 converge towards intermediate portions of an adjacent vane at an acute angle thereto.

In the preferred embodiment of the invention the vane portions 34 extend at an angle of approximately 45 degrees to a radial line passing through the center of the 3 disc. Iconsider a 45 degree angle preferable, but have found that other acute angles will provide improved results within to 60 degrees. The straight line portion 34 at its outer end terminate in the curved Wall portions 35 and the trailing portions 36 of the respective vanes defined by arcs of increasing radii, said vanes becoming progressively thicker in cross section towards their outer ends.

The straight line portion 3:4 of a particular vane defines with an intermediate portion of an adjacent vane, an inlet of decreasing cross sectional area defining the respective venturi openings 38 between vanes. These provide for an increased initial velocity of the material being pumped. a

The outer portions of the respective vanes beyond said venturi are of gradually increasing radii to thereby guarantee and maintain this initial high velocity in the outer portions 39 of said passages defined between the respective vane ends.

Accordingly there is a substantial constant velocity of delivery of the pumped fluids into the annular chamber 40 within said casing for communication with discharge 25.

The important point in connection with the vane structure is the fact that the initial straight line portions of the respective vanes converge towards intermediate portions of an adjacent vane at an acute angle, preferably around 45 degrees, to provide for an increased initial velocity of the pumped material at the inner ends of the respective passageways 39.

In view of the increasing radii towards the outer ends of the respective vanes,'the friction against movement of the fluid is substantially reduced and with the action of centrifugal force the velocity of pumped fluid, or material is maintained so as to provide a continued and even flow and at a greatly increased efiiciency.

A test was conducted comparing a standard Penberthy Sump Pump made by the Penberthy Injector Company with a pump constructed in accordance with the present invention. The test was conducted by The General Electric Apparatus Sales Division. The results and figures were as follows:

1. Penberthy pump specifications:

Impellers both, 4%" diameter R. P. Emericks pump:

a. Franklin Motor-Ms H.P.110 volts-1725 r.p.m.

b. Current at 5.6 amps. with motor at operating temperature c. Gallons water pumped-87.7 per minute (5263 per hour) Both pumps pumped against a 4 /2, foot head. They 6 The present impeller eliminates most of the high and low pressure areas and for that reason alone increases the efficiency of the Emerick unit over 100 percent. A similar improvement can be expected on any centrifugal impeller type pump by using this new impeller design. In all cases the pump unit can be reduced in size if a given gallonage is required. In other cases it may be easier to reduce the rpm. and there by reduce fuel consumption.

Having described my invention, reference should now be had to the following claims:

I claim:

1. In a centrifugal pump having a casing including a central intake on one side and a tangential outlet, the opposite side of said casing being ap'ertured to receive a power driven shaft, an open impeller loosely positioned within and rotatable in said casing and comprising a disc with a central hub adapted for securing to said shaft, a plurality of separate spirally spaced vanes of uniform height joined to and extending laterally of said disc throughout a substantial portion of the Width of said casing, the inner ends of said vanes being radially spaced outwardly of the center of said disc defining an axial inlet in registry with the casing inlet and a plurality of radial inlets between adjacent vanes, the surfaces defining each vane consisting of a straight line portion for a part of its length arranged at an acute angle to a normal line from the disc center and converging towards an intermediate portion of an adjacent vane defining a radial passage of gradually reduced cross sectional area terminating in a venturi, the width of said venturi being approximately double the adjacent vane thickness outer portions of said vanes being defined by arcs of increasing radii towards their outer ends providing outlet passages of increasing cross sectional area terminating at the periphery of said disc in communication with the interior of said casing said straight vane portions being approximately /3 the radial distance from the beginning of the vane to the periphery of the disc, and approximately /5 the length of the outer portions of said vanes, said straight line portions being of uniform thickness with opposite surfaces parallel, said outer portions for the greater part of their length being of substantially uniform thickness with their opposite surfaces substantially parallel.

2. In the pump of claim 1, said acute angle being approximately 45 degrees.

3. In the pump of claim 1, said acute angle being in the range of 10 to degrees.

4. In the pump of claim 1, said straight line vane portions being in the range of 15 to 60 percent of the radial distance from the beginning of the vane to the periphery of the disc.

References Cited in the file of this patent UNITED STATES PATENTS 2,242,714 Willson May 20, 1941 FOREIGN PATENTS 253,302 Great Britain June 16, 1926 506,324 Great Britain May 25, 1935 $10,746 Italy J an. 22, 1955

Images