US2963978A

US2963978A - Centrifugal pump impeller

Info

Publication number: US2963978A
Application number: US346971A
Authority: US
Inventors: Carl A Namur
Original assignee: GIRTON Manufacturing Co
Current assignee: GIRTON Manufacturing Co
Priority date: 1952-09-22
Filing date: 1953-04-06
Publication date: 1960-12-13
Anticipated expiration: 1977-12-13

Description

Dec. 13, 1960 c. A. NAMUR CENTRIFUGAL PUMP IMPELLER Original Filed Sept. 22, 1952 4 Sheets-Sheet 1 n m v nvwzmox Chrl (J2 Nam/a Dec. 13, 1960 c. A. NAMUR CENTRIFUGAL PUMP IMPELLER 4 Sheets-Sheet 2 Original Filed Sept. 22. 1952 R m m m Carl 0?. Namafl glmmy g Dec. 13, 1960 c. A. NAMUR CENTRIFUGAL PUMP IMPELLER Original Filed Sept. 22, 1952 4 Sheets-Sheet 3 /I/I/I/I/I/I/IIIA INVENTOR.

Dec. 13, 1960 c. A. NAMUR CENTRIFUGAL PUMP IMPELLER 4 Sheets-Sheet 4 Original Filed Sept. 22, 1952 INVENTOR. Caz/Z c1 2. Nam/a7" BY 2,953,978 Patented Dec. 13, 1960 'CENTRIFUGAL PUMP IMPELLER Carl A. Namur, Millville, Pa., assignor to Girton Manufacturing Company, Millville, Pa., a corporation of Pennsylvania Original application Sept. 22, 1952, Ser. No. 319,837,

now Patent No. 2,784,673, dated Mar. '12, 1957. Divided and this application Apr. 6, 1953, Ser. No. 346,971

Claims. (Cl. 103-103) This invention relates to centrifugal pumps and the use thereof. More particularly this invention relates to improvements in centrifugal pumps whereby they are adapted particularly well for uses wherein the pumps must frequently be disassembled and reassembled incidental to the cleaning thereof, and wherein they are frequently operated under greatly varying conditions of discharge pressures, and wherein they are frequently used to pump products of appreciably difierent viscosities.

This application is a division of my co-pending application Serial No. 310,837, filed September 22, 1952, entitled Centrifugal Pump, now Patent No. 2,784,673.

Some of the primary objects of this invention are to provide a sanitary type, centrifugal pump, which may be easily and quickly assembled and disassembled, which is comprised of relatively few operating parts, which is of symmetrical design, which is provided with a self regulating feathering type impeller, and which is provided with a self adjusting, sanitary rotary seal for sealing the aperture in the pump housing through which the impeller shaft extends into the pump housing.

A further object of this invention is to provide an improved method for the non-turbulous pumping of fluid, such as milk, against changeable conditions of discharge pressure head by the use of constant speed centrifugal pumps provided with self feathering type impellers.

An important object of this invention is to provide an improved support structure for a sectional casing for a pump.

Other objectives and important aspects and advantages of this invention may be more readily determined from a consideration of the following description of the invention when read in connection with the accompanying drawings in which:

Figure l is a side elevational view, partially in section, showing the improved pump unit;

Figure 2 is a front elevational view of the pump shown in Figure 1 of the drawings;

Figure 3 is a sectional view taken along line 3-3 of Figure 1 of the drawings, together with a superimposed dotted line illustration of the maximum radial contraction of the blades of the impeller of the improved pump;

Figure 4 is a sectional View taken along line 44 of Figure l of the drawings;

Figure 5 is a side elevational view, partially in section of a portion of the pump impeller shaft operating seal ring, illustrating the manner of removal of the seal ring from the impeller shaft;

Figure 6 is a side elevational view, partially in section, of a portion of the impeller shaft and the apertured portion of the rear wall of the pump housing, illustrating the manner of disassembling the pump impeller shaft from the pump housing;

- Figure 7 is a side elevational view of a modified arrangement of a portion of the pump impeller shaft and a portion ofthe driving motor shaft illustrating the use of permanent magnets to urge the impeller shaft axially along the motor shaft toward the jaw clutch collar on the motor shaft;

Figure 8 is an enlarged sectional view of the complementary flanged edges of the sections of the pump casing seated in the pump casing support;

Figure 9 is a view, partially in section, illustrating the relative position of assembly of elements of the improved P p;

Figure 10 is a diagrammatic view illustrating a manner of use of the improved pump in pumping material against different pressure heads; and

Figure 11 is a view of a modified impeller of rigid construction usable in the improved pump.

Referring to the preferred embodiment of the invention as illustrated in the drawings, in which like elements are identified by like numerals, 1 represents a source of driving power, such as an electrical motor of the sanitary type. The motor 1, as clearly illustrated in Figure 1 of the drawings, is provided with ball type feet 2, and is also provided with a central drive shaft 3 extending outwardly from one end of the motor casing, centrally thereof. Shaft 3 is adapted to deliver a uniform driving torque at a constant number of revolutions of the shaft per minute.

An annular shoulder 4 formed on the shaft end of the motor casing, surrounds the shaft 3 and is concentric therewith. Shoulder 4 is utilized in the support of and positioning of an annular yoke 5. One end of the yoke 5 is snugly fitted over the shoulder 4 and rigidly secured to the frame of the motor 1 in concentric arrangement with the axis of the drive shaft 3 by bolts 6 which extend through lugs 7 formed on the inside of yoke 5 and then extend into the frame of motor 1 to which they are secured.

The end of yoke 5 farthest removed from the motor 1 is provided with an annular end having parallel inner and outer, longitudinally extending, peripheral portions 8 and 9 respectively. The peripheral portions 8 and 9 are parallel to and concentric with the axis of the drive shaft 3 and are spaced approximately opposite the adjacent end of the shaft 3. The annular end face 10 of the yoke 5 intermediate the peripheral portions 8 and 9 is also concentric with the drive shaft 3 and lies in a plane perpendicular to the axis of the shaft 3 and the surfaces 8 and 9. An inwardly extending, annular flange 11, of rectangular cross section, is formed on the inner surface of the yoke 5 contiguous with the inner peripheral portion 8. Flange 11 has an inner annular peripheral surface 12 concentric with and parallel to the axis of shaft 3. Flange 11 also has opposed, parallel, transversely extending,

annular side walls

13 and 14 concentric with the axis of shaft 3 and parallel to the end face 10 of yoke 5. The contiguous, concentric surfaces or shoulders 8 [and 13 form between themselves an annular groove on the inside of the end of the yoke 5.

A pump housing consisting of interfitted, substantially circular, centrally apertured, front and

rear housing sections

15 and 16 respectively, is releasably supported on the yoke 5 in concentric arrangement with the axis of the shaft 3.

The rear, cup shaped, housing section or rear end face 16 of the pump casing is formed primarily of a flat plate like portion 17, substantially flat on both sides thereof, which sides are parallel one to another and to the end face 10 of yoke 5 and are also perpendicular to the axis of the shaft 3. The rear end face .16 is centrally ported and is provided with a rearwardly extending and outwardly converging annular flange 18. The flange 18 is in the form of the outer inclined surface of a frustum of a cone and is concentric with the axis of the drive shaft 3 and defines the central aperture in the end face 16'. A laterally extending flange 19, formed integrally with the fiat portion 17 extends rearwardly from the outer periphery of the flat portion 17 of the end face 16 and is perpendicular to the flat portion 17 and is also concentric with the axis of the shaft and is also parallel to the inner peripheral portion 8 of the yoke but spaced from the portion 8. An annular, transversely etxending flange 20 formed integrally with the flange 19 extends radially from the rear edge of flange 19 parallel to the flat portion 17 of the end face 16 and concentric with the inner yoke flange 11 land overlappingly abutting and parallel to the front face 13 of flange 11. The free, outer annular edge 21 of flange 20 is concentric with, parallel to, and abuts against the inner peripheral portion 8 of the yoke 5.

The front, cup shaped, pump casing or housing section 15 has its front face formed primarily of a flat plate-like portion 22 substantially flat on both sides thereof which sides are parallel one to another and to the flat sides 17 of the rear pump face 16 and to the end face of yoke 5 and are also perpendicular to the axis of the drive shaft 3. The front end face is centrally ported and is provided with a forwardly extending and outwardly converging inlet throat portion 23 which defines the aperture in the front face 15. The wall of the throat portion 23 is in the shape of the outer inclined surface of a frustum of a cone and is concentric with the axis of the shaft 3' and terminates at its outer end in a juncture with a conventional cylindrical pipe connection 24. A laterally extending flange 25 formed integrally with the flat portion 22 of front face 15 extends rearwardly from the outer periphery of the flat portion 22 of the front end face 15 and is perpendicular to the flat portion 22 and is also concentric with the axis of the shaft 3 and parallel to and concentric with flange 19 of the rear end face 16 and is also parallel to and concentric with but spaced from the inner peripheral portion 8 of the yoke 5. An annular, transversely extending flange 26 formed integrally with the flange 25, extends outwardly and rearwardly at an angle to the flange 25 from the rear edge of the flange 25 and is concentric with the axis of the shaft 3 and the peripheral portion 8 of yoke 5 and is generally of the configuration of the inclined surface of a frustum of a cone and generally overlaps the front of the flange but preferably out of contact therewith. The free outer annular edge 27 of flange 26 is concentric with, parallel to and abuts against the inner peripheral portion 8 of the yoke 5. A tangential discharge connection 85 communicates with the interior of the pump housing through an aperture in the flange 25.

To seal the

sections

15 and 16 of the pump housing or casing one to another an annular gasket 28, preferably of circular cross sections is mounted on the rear section or end face 16 and seated in the annular groove 29 in the outer face of the flange 19 immediately adjacent the flange 20. Gasket 28 is of such a cross section dimension that it will be sealingly compressed between the

flanges

19, 20, and 26 when the

casing sections

15 and 16 and the gasket 28 are assembled in the manner described. V

Telescoped snugly over the drive shaft 3 is a circular centrally bored impeller shaft 30 the faces of which are concentric with, and supported against radial displacement by the drive shaft 3. The cylindrical impeller shaft 30, centrally bored partially through the length thereof, is telescoped over the cylindrical drive shaft 3, over which drive shaft it fits snugly in coaxial arrangement and with the end of the bore in the impeller shaft 30 immediately adjacent the end of the shaft 3. The free end of the impeller shaft 30 extends into the pump housing through the central aperture in the rear end face 16 of the pump housing, out of contact with the flange 18 but concentric with the axis thereof. The end of the impeller shaft 30 which extends into the pump casing is provided with a transverse, peripheral, annular flange 31 having parallel rear and front side walls or

shoulders

32 and 33 which are perpendicular to the axis of the drive shaft 3 and parallel to the

flat face portions

17 and 22 of the pump casing near and

front sections

16 and 15 respectively and also parallel to and concentric with the annular end face 10 of the yoke 5.

To facilitate ready escape of air in assembly and to facilitate cleaning, a diametrical transverse hole 34 intersecting the end of the axial bore is provided in shaft 30, thus permitting ready assembly of shaft on. shaft 3 with the inner surface 35 defining the bore in shaft 30 closely fitted on to the outer cylindrical surface of drive shaft 3.

The rear end of the impeller shaft 30 is provided with a jaw clutch arrangement consisting of the transverse and

axial shoulders

36 and 37 respectively formed in the rear end portion of the impeller shaft 30 for driving engagement with the

complementary shoulders

38 and 39 respectively on the collar 40 secured to the drive shaft 3 by key bolt 41. In normal operation the driving torque is transferred from shoulder 39 to shoulder 37 and the thrust shoulders 36 and 38 do not engage one another for reasons which will become more apparent hereinafter.

A U-shaped spring clip 42 is rigidly seated at one end in a slot in the collar 40 and secured thereto by screw 43. The free end 44 of the spring clip 42 is in the form of a cam follower and overlaps the end of impeller shaft 30 opposite the shoulder 37 and under tension engages the peripheral cam 45 on. the extreme rear portion of the outer periphery of the impeller shaft 30 and when the follower 44 is normally in contact with the upwardly and rearwardly inclined cam face 46 the impeller shaft 30 is urged rearwardly on the drive shaft 3. In the pump assembly operation the cam follower end 44 of spring clip 42 engages the upwardly and forwardly inclined cam face 47 of earn 45 to aid in seating the follower 44 properly upon the cam face 46.

The end of the impeller shaft 30 which extends into the pump housing is provided with two parallel, forwardly extending, cylindrical studs or hinge pins or pivots 48 which are equally spaced from and parallel to the axis of the shaft 3 and extend forwardly from the front face of the shaft 30 which is flush with the face 33 of the flange 31. The outer edges of the pivots 48 are spaced slightly inwardly of the outer edges of the shaft 30. Each of the pivots 48 are of a length approximately equal to the internal depth of the pump casing between the

flat surfaces

17 and 22, and each of the pivots 43 is provided adjacent its free end with a peripheral groove 49.

In the preferred embodiment of the invention the improved pump inclndes two rigid impeller blades 50 having substantially flat front and rear parallel faces 51 and 52 respectively which are parallel to and spaced slightly from the flat faces 17 and 22 of the

pump housing sections

15 and 16 and lie in parallel planes perpendicular to the axis of the shaft 3. The outer end 53 of each of the blades 50 is perpendicular to the front and rear faces 5-1 and 52 and parallel to the axis of the shaft 3 and spaced from the flange 25 of the housing section 15. The curved or bowed

side walls

54 and 55 of the impeller blades 50 are parallel and arcuate and are perpendicular to the planes of the

flat portions

17 and 22 of the pump sections 15 and '16. In operation the impeller blades 50 are rotated clockwise as viewed in Figure 3 of the drawings with the convex surface 55 of the blades 50 comprising the leading surface and the concave surface 54 comprising the following surface. Each of the blades 50 is formed with an oifset inner end portion having a flat front surface 56 parallel to the front face 51 of the blade 50, and which offset portion is slightlynarrower than the width .of the blades intermediate the parallel front and rear faces 51 and 52. A pivot or hinge pin receiving cylindrical bearing opening 57 is provided immediately adjacent the inner end of the blades 50 through which the pivot pins or studs 48 extend in bearing contact therewith. The blades 50 are releasably secured in hinged operative position upon the pivot pins 48 by means of the engagement of the branches of the hairpin-like, outwardly, expandable, spring clip 58 in the grooves 49 of the studs 48. The clip pin 58 is releasably locked in groove 49 due to the spring tension of the pin 58, and also due to the effect of centrifugal force upon the branches of the pin 58 when the impeller Shaft 30 is rotated. The width of the inner end portions of each of the blades 50 through which the pivots 48 extend is substantially equal to the length of the studs 48 intermediate to the groove 49 and the front end of the impeller shaft 30.

A seal ring 59 is provided to seal the aperture in the rear section 16 of the pump casing about the impeller shaft 30. The seal ring 59 is formed of any suitable anti friction material such as for example, Bakelite, hard rubber, nylon or other suitable material, and has a cylindrical inner periphery 60 of a diameter slightly larger than the outer diameter of the impeller shaft 30. The seal ring 59 is provided with a flat front face 61 which is perpendicular to the axis of the shaft 3 and parallel to and abutting in sealing contact against the rear surface 32 of the flange 31 on the shaft 30. The width of the annular sealing surface or face 61 of the ring 59 is such that the outer edge thereof is flush with the outer edge of the sealing face 32 of the flange 31. The seal ring 59 is provided with an annular outer peripheral surface 62 which joins the front face 61 of the seal ring 59 with the rear face of the seal ring. The surface 62 converges inwardly from the front face of the ring 59 toward the rear face of the ring 59 so as to provide a seal ring wherein a lateral cross section as illustrated in Figure of the drawings thereof would be provided with a convex surface 62. The ring 59 is seated within the flange 18 by the sealing engagement of the convex surface 62 of the ring 59 with the inner conical surface 63 of the flange 18.

In the operation of the improved pump the sealing engagement between the seal face 61 of the ring 59 and seal face 32 of the flange 31 is maintained, at least in part, by the spring 42 which, through engagement with the cam face 46 urges the impeller shaft 30 rearwardly whereby the flange 31 compresses the conical surface 62 of the ring 59 sealingly against the surface 63 of the flange 18 while simultaneously urging the seal face 32 of the flange 31 into sealing engagement with the face 61 of ring 59.

In the normal operation of the pumps the seal ring 59 is prevented from rotating within the flange 18 by virtue of the inter fitting relation between the slot 64 in the rear edge of the seal ring 59 and the complementary key 65 within the flange 18.

When the operative elements of the improved pump have been assembled in the arrangement as heretofore set forth, the pump housing is maintained in its operative position on the yoke 5 with the sections and 16 sealed one to another by means of the compressed gasket 28 due to the rearward thrust against the front section 15 of the pump casing by the compression bracket 66. The opposed arms of the compression bracket 66 are hinged at one end by hinge pin 67 to a supporting stud 68 anchored in a lug 69 on the outer periphery of the yoke 5.

An oppositely disposed lug 70 on the yoke 5 is utilized to support a tension screw 71 on the free end of which is threaded a nut 72 which overlappingly engages the free ends of the opposed bracket arms 66 which are rigidly secured together by the cross pin 73. The ap propriate adjustment of the nut 72 on the screw 71 brings about the desired compression of the front pump housing head 15 against the gasket 28.

In the operation of a pump embodying the present invention, the position of the impeller blades 50 is determined in part by the effect of centrifugal force, which would tend to cause the blades 50 to assume a position of maximum radial extension, and is determined in part by the resistance to movement of the material being pumped, either due to viscosity or discharge pressure head, which will tend to cause the blades 50 to assume a position of minimum radial extension as illustrated by the dotted line representations of the blades 50 in Figure 3 of the drawings,

Such self adjustment or automatic feathering of the rigid, but pivoted impeller blades 50 which are eccentrically hinged to the rotary impeller shaft and arranged to rotate concentrically within a cylindrical pump casing at an established speed of rotation, and which impeller has an extreme outer diameter less than the inner diameter of the pump casing, always provides a fluid circulating space between the end of the impeller blade and the cooperating walls of the pump casing. The adjustability of the impeller blades 50 determines the radial depth of the fluid circulating space. In such adjustment of the impeller blade 56 the outer free end thereof is swingable, from its position of maximum radial extension, toward the axis of rotation of the impeller shaft 30, and in being so moved travels through a path of progressively diminishing radial extension. The impeller blades 50 in their movement from their maximum extended position to positions of minimum extension pivot about pivots 48 through an arc of at least degrees as clearly illustrated in Figure 3 of the drawings until the pivot ends of the blades 50 overlap one another, thereby appreciably reducing the effective area of the sweep of the impeller blades 59. The blades 50 are pivotable on pivots 48 through an arc in excess of degrees. Under these conditions of possible movement of the im peller blade 5% responsive to such conditions as discharge pressure head, the free end of the impeller blade 50 will under low pressure conditions be caused to travel through an outermost orbital circular path radially in- Wardly of the inner periphery of the casing wall 25, and to travel under conditions of high discharge pressure head along an innermost orbital circular path radially closer to the axis of rotation, and to travel through orbital circular paths intermediate the outermost and innermost paths depending on the conditions of dis charge pressure head.

In Figure 10 of the drawings there is illustrated a pumping system utilizing an improved pump according to this invention wherein the fluid is supplied to the pump under a slight static head or by suction from supply reservoir 74 through the supply pipe 75 to the pump. The pump then delivers the fluid under pressure into the discharge conduit 76. From the conduit 76 the fluid may be discharged under pressure at a low elevation against a low discharge pressure head by opening the lower valve 79 and discharging the fluid into reservoir 77 or the fluid may be discharged at a higher elevation against a higher pressure head by opening the upper valve 79 and discharging the fluid into the reservoir 78. In the use of the improved pump in such a pumping system the working capacity of the pump is automatically adjusted in proportion to the discharge pressure which in turn determines the volume of fluid contained in the pump chamber while the fluid is subject to a given discharge pressure head and that in turn, in an important degree, determines the extent of radial expansion of the eccentn'cally pivoted impeller blades.

Figure 11 of the drawings illustrates a modified form of pump impeller 80 which is comprised of one rigid barlike element having generally the configurations of the result of the combining of two impeller blades 50. The modified form of impeller blade 80 is provided with two bearing ports in the mid section thereof to receive the studs 48 of the impeller shaft 30.

Figure 7 of the drawings illustrates an arrangement for urging the impeller shaft 30 rearwardly on the drive shaft 4 3 to maintain the rotary seal in sealing position in the aperture of the rear face 16 of the pump housing by the use of magnets. To this end the modified form of the impeller shaft 30 is provided with opposed peripheral flange-like elements 81 and 82 immediately adjacent the jaw clutch portions of the shaft '30 and spaced directly opposite and adjacent to magnets 83 secured by screws 84 to the collar 40 on the drive shaft 3.

Having thus described the illustrated and preferred embodiment of this invention in a pump and method of its use, the invention is not to be restricted to the specifically illustrated embodiment thereof as set forth in the accompanying drawings and as hereinbefore described, except in so far as necessary by the prior art and the appended claims.

The invention is hereby claimed as follows:

1. A pump for fluid, comprising in combination, a rotatable impeller drive means, impeller housing means, said housing means having spaced front and rear face portions which are each substantially flat and which are substantially parallel one to another and having housing side wall means extending intermediate the circumferential peripheral portions of said face portions, impeller pivot means carried by said drive means eccentrically with respect to the axis of rotation of said drive means, said pivot means being generally of cylindrical shape with the longitudinal axis thereof parallel to the axis of rotation of said drive means, impeller means releasably pivoted to and supported upon said pivot means and extensible outwardly intermediate said face portions toward said side Wall means, said impeller means being pivotable through an arc of at least ninety degrees and being provided with a convex impelling surface of a width substantially equal to the distance intermediate the adjacent surfaces of said face portions and being of such a length and of such construction and arrangement that the center of gravity of said impeller means is located radially outwardly from said pivot means, said impeller means being so constructed and arranged that when said pump is operating said impeller means is radially extended upon said pivot means solely by centrifugal force and is radially depressed responsive to an increase in discharge pressure of the fluid being pumped, and quickly releasable lock means releasably securing said impeller means upon said pivot means.

2. A centrifugal pump, comprising in combination, a rotatable drive shaft for a pump impeller, a pump housing of substantially cylindrical configuration into which an end of said drive shaft extends, said pump housing having spaced front and rear face portions which are each substantially flat and which are each substantially circular and which are each substantially parallel one to another and perpendicular to the axis of said drive shaft and having a side wall intermediate the adjacent circular peripheral edges of said face portions, said side wall being concentric With the axis of said drive shaft, impeller pivots extending longitudinally from and carried by the end of said drive shaft Within said housing, said pivots each being of cylindrical configuration with its respective longitudinal axis positioned parallel to the axis of rotation of said drive shaft and being positioned to rotate in an orbit of a diameter less than the diameter of said drive shaft, ro-

- tatable and substantially inflexible impeller vanes releasably pivoted to and supported upon said pivots, said vanes each being so constructed and arranged and of such length that in any position of pivoting of each of said vanes upon its respective pivot the center of gravity of each of said vanes will be positioned radially outwardly from the axis of rotation of said'dnive shaft and from the orbit of rotation of the axis of said pivots, said impeller vanes being rotatable through a circular orbit intermediate said parallel faces and intermediate the axis of rotation of said drive shaft and'said side wall and each impeller vane being pivotab-le upon its pivot through an arc of at least ninety degrees, the-freeend of. each of said impeller vanes when pivoted outwardly from the axis of said drive shaft by centrifugal force to the maximum radial extension thereof and being free of contact with said side wall, said impeller vanes being of a width substantially equal to the distance between adjacent surfaces of said faces defining a portion of the orbit of rotation of said vanes and being radially depressable responsive to an increase in pump discharge pressure or an increase in viscosity of the fluid pumped, and readily releasable lock means releasably securing said vanes to said pivots.

3. In combination, an elongated and rotatable impeller drive shaft, impeller pivot means carried by and extending from the end of said drive shaft and arranged parallel to the axis of said drive shaft, and impeller means pivoted to and supported upon said pivot means and extending outwardly beyond the outer periphery of said drive shaft, said pivot means being rotatable with said shaft and in an orbit whose diameter is less than the diameter of said shaft.

4. A device according to claim 3, wherein said impeller means is provided with a convex leading surface and a concave trailing surface, said convex leading surface comprises the impelling surface when said impeller is operated.

5. In combination, a housing, an elongated rotatable impeller drive shaft extending into said housing concentrically through an aperture in said housing, rotatable impeller means releasably pivoted to said drive shaft eccentrically of the axis of rotation of said drive shaft and at a radial distance from the axis of said shaft less than the radius of the aperture in said housing, and quickly releasable clamp-type locking means for releasably securing said impeller means to said drive shaft.

References Cited in the file of this patent UNITED STATES PATENTS