US2882829A

US2882829A - Fabricated impeller for pumps

Info

Publication number: US2882829A
Application number: US564488A
Authority: US
Inventors: John B Wade
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1956-02-09
Filing date: 1956-02-09
Publication date: 1959-04-21
Anticipated expiration: 1976-04-21

Description

April 1959 J. B. WADE 2,882,829

FABRICATED IMPELLER FOR PUMPS Filed Feb. 9, 1956 3 Sheets-Sheet l El f:

TIE'| EI V 'F IB EI TIE| '7 BNVEN'I'OR JOHN B. WADE ATTORNEY April 21, 1959 J. B. WADE 2,882,829

FABRICATED IMPELLER FOR PUMPS Filed Feb. 9, 1956 s Sheets-Sheet 2 FIE E3 INVENTOR JOHN B. WADE ATTORNEY April 21, 1959 V J. B. WADE 2,832,829

FABRICATED IMPELLER FOR PUMPS Filed Feb. 9, 1956 3 Sheets-Sheet 3 mvEN'roR 7 JOHN B. WADE WWW 12%,

ATTORNEY United States Patent FABRICATED IMPELLER non PUMPS John B. Wade, Arcadia, Califi, assignor to Food Machinery and Chemical Corporation, San Jose, Calif., a corporation of Delaware Application February 9, 1956, Serial No. 564,488

7 Claims. (Cl. 103-115) This invention appertains to centrifugal pumps and more particularly to a novel fabricated impeller for use therein.

Heretofore, impellers for centrifugal pumps have been customarily made by casting which is an expensive and time consuming operation. It is therefore an object of this invention to provide an impeller which may be fabricated inexpensively from a plurality of identical elements individually formed on a punch press and then assembled into a completed unit.

Another object of the invention is to provide an impeller fabricated from a plurality of elements and having a minimum vane thickness which is less than that which can be obtained by casting.

Various other objects of the instant invention will become apparent in reading the following detailed specifiction in conjunction with the accompanying drawings,

, wherein:

Fig. 1 is a perspective, partly cut away, of a pump having an open face impeller embodying the principles of the invention.

Fig. 2 is a plan of the impeller shown in Fig. 1.

Fig. 3 is a section taken on line 3-3 of Fig. 2.

Fig. 4 is a plan of one of the fiat crescent shaped impeller elements.

Figs. 5, 6 and 7 are sections taken on lines 5-5, 6--6 and 7-7, respectively, of Fig. 4.

Fig, 8 is a fragmentary plan, partly broken away, of

a modified form of impeller.

Fig. 9 is a section taken on line 99 of Fig. 8.

Fig. 10 is a plan of one of the elements of the impeller shown in Figs. 8 and 9.

In general a centrifugal pump, such as that disclosed for illustrative purposes in Fig. 1, comprises a housing 17 provided with an inlet opening 18 and a discharge opening 19. A shaft 20 is rotatably supported in the housing 17 and a suitable packing 21 is provided to seal 7 around the shaft 20 where it extends through the housing 17. An impeller, generally indicated at 22, is fixed to the end of the shaft 20 within the housing 17 and a suitable motor (not shown) is provided to rotate the shaft 20 and hence the impeller 22 at relatively high speed. Impellers used in centrifugal pumps are generally of two types, namely, open face and closed. The impeller illustrated in Fig. l is of the open face type and comprises a fiat shroud plate or disc having a plurality of spiral vanes 23 which extend substantially at right angles to the surface of the shroud plate into close proximity with the flat inner surface of the end plate 24 of the housing 17. An impeller of the closed type would be constructed essentially the same as that shown in Fig. 1 with the exception that a second flat shroud plate or disc would be fixed to the outer ends of the spiral vanes 23 in the manner illustrated in Fig. 8. The second shroud plate would be provided with a central aperture in register with the inlet port 18 to permit the liquid entering therethrough to enter between the two shroud plates.

2,882,829 Patented Apr. 21, 1959 In the operation of a centrifugal pump having an impeller of either type, the rapid rotation of the impeller and the vanes associated therewith causes the liquid entering through the central inlet opening 18 to be thrown outwardly into an annular channel 25 adjacent the periphery of the impeller and discharged through the port 19 which is connected tangentially with the channel 25.

As hereinabove stated, the impellers heretofore used in pumps of this type were cast as a unit and hence required complicated mold structures and very diflicult and expensive machining operations. The improved impeller of the instant invention is best illustrated in Figs. 2 and 3, and comprises a plurality of identical flat crescent shaped elements 26, there being five shown in the particular illustration chosen, but it is to be understood that a greater or fewer number of elements may be employed depending on the number of impeller blades desired.

Turning now to Figs. 4, 5, 6 and 7, each of the crescent shaped elements 26 is preferably formed from sheet material on a punch press and comprises a fiat crescent shaped body portion 34 having convex and

concave edges

35 and 36, respectively, each defining a spiral. An upturned flange 23 is formed integral with and extends along the convex edge 35 to form an impeller blade. A downwardly offset portion 37 having a constant width is located adjacent the concave edge 36 of the element and is adapted to overlap body portion 34 of the next adjacent element 26 in a manner described hereinbelow. Since the element is formed from sheet material, it is obvious that the vane thickness is the same as the thickness of the sheet and thus may be very accurately controlled.

The innermost end of the concave edge 36 of the element 26 is provided with an arcuate cut-out 38 adapted to receive a hub 39 shown in Figs. 1, 2 and 3. An arcuate edge 40 connects the outer end of the convex spiral edge 35 with the outer end of the concave spiral edge 41 of the offset flange 37. The center of curvature of the edge 40 is the same as the center of curvature of the arcuate cut-out 38, whereby when the elements 26 are assembled in the manner illustrated in Fig. 2, the edge portions 40 join together to define the outer circular edge of the impeller 22 and the arcuate cut-out portions 38 join together to define a circular aperture to receive the hub 39.

In the assembly of the impeller, the several elements 26 (in the instant illustration five) are arranged in nesting relation with the offset flange 37 of each underlying the body portion 34 of the element next adjacent, and the elements are welded or brazed together. The hub 39 having a flange 42 is then inserted in the aperture defined by the cut-outs 38 with the flange 42 abutting the surfaces of the elements 26, and Welded or brazed in place. The flat portions 34 of the elements 26 form the shroud of the impeller and the overlapping flanges 37 form spiral stiffening ribs on the rear of the shroud and act as repelling vanes to reduce the pressure on the pump packing.

While the flanges 23 forming the impeller blades are illustrated herein as having a progressively changing angle with respect to the shroud, it is obvious that the basic concept of individual elements assembled into a complete impeller is equally applicable to impellers wherein the blade elements are normal to the shroud throughout their length.

Turning now to the modification shown in Figs. 8, 9 and 10, the structure shown therein is similar to that shown in Figs. 1 to 7, and like reference numerals with the postscript a appended thereto are used to denote the like elements. One of the principal differences in the construction of this embodiment is that the flanges 37a are extended to completely cover the back of the shroud formed by the flat portions 34a of the elements 26a when provide a smooth rear surface on the impeller. Another difierence is that a front shroud comprising a plate 43 is fastened to the front edges of the flanges 23a to provide a closed impeller structure. The plate 43 is provided with a central aperture 44 defined by an outwardly turned annular flange 45 adapted to register with the inlet port of a pump housing to permit the entrance of liquid into the impeller.

The assembly of the closed impeller, shown in Figs. 8, 9 and 10, is essentially the same as that described above in connection with the open face impeller shown in Figs. 2 to 7. First the several crescent shaped elements 26a are arranged in nesting relation with the oifset flange 37a of each underlying the body portion 34a of the element next adjacent, and the elements are welded or brazed together. The shroud plate 43 is then welded or brazed to the front edges of the flanges 23a. It will be noted that the flat portions 34a of the elements 26a form the rear shroud of the impeller and that the edges 41a of the overlapping oflset flanges 37a extend in abutting relation with the offset of the element next adjacent thereto whereby the impeller thus formed is provided with a smooth rear surface.

While I have shown and described two embodiments of the invention, it is obvious that various changes may be made therein without departing from the spirit of the invention as defined in the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. An impeller for a centrifugal pump comprising a plurality of one-piece crescent shaped elements joined together to form a fiat shroud plate, each of said elements having a flat portion defined by spiral convex and concave edges, a flange integral with and extending substantially normal to said flat portion adjacent to and substantially coextensive with one edge thereof to form a vane of the impeller, and a second flange integral with and parallel to but downwardly offset from the flat portion of said element adjacent the other edge thereof.

2. An impeller for a centrifugal pump comprising a plurality of crescent shaped elements joined together to form a flat shroud plate, each of said elements having a flat portion defined by spiral convex and concave edges, each of said elements having a flange extending substantially normal to said flat portion adjacent to and substantially coextensive with one edge thereof to form a vane of the impeller, a second flange parallel to but offset from the flat portion of said element adjacent the other edge thereof, an arcuate cut-out adjacent the innermost end of the concave edge of said spiral element, and an arcuate edge connecting the outer end of said convex and concave edges of said element, the center of curvature of said arcuate edge being concident with the center of curvature of said cut-out, the arcuate edges of said elements cooperating to form a circular outer edge for the shroud plate.

3. An impeller for a centrifugal pump comprising a plurality of crescent shaped elements, each of said elements having a flat portion defined by spiral convex and concave edges, a flange extending substantially normal to said flat portion adjacent to and substantially coextensive with one edge thereof to form a vane of the impeller, a second flange parallel to but offset from the flat portion of said element adjacent the other edge thereof, said elements being anranged in nesting relation with each other and fixed together with the offset flange portion of each underlying the element next adjacent thereto to form a flat shroud plate with a plurality of spaced vanes.

4. An impeller for a centrifugal pump comprising a plurality of one-piece crescent shaped elements, each of said elements having a flat portion defined by spiral convex and concave edges, a flange integral with and extending substantially normal to said flat portion adjacent to and substantially coextensive with one edge thereof, a second flange integral with and parallel to but offset from the flat portion of said element adjacent the other edge thereof, an arcuate edge connecting the outer end of said convex and concave edges of said element, said elements being arranged in nesting relation with each other and fixed together with the offset flange portion of each underlying the convex edge portion of the element next adjacent thereto to form a flat shroud plate, the arcuate edge portions of-the several elements defining a circular outer edge to the plate thus formed, and the spiral concave edges of said second flanges defining repelling vanes on the side of said shroud plate opposite said first mentioned flange.

5. An impeller for a centrifugal pump comprising a plurality of one-piece crescent shaped elements, each of said elements having a flat portion defined by spiral convex and concave edges, each of said elements having a flange integral with and extending substantially normal to said flat portion adjacent to and substantially coextensive with one edge thereof, a second flange integral with and parallel to but downwardly offset from the flat portion of said element adjacent the other edge thereof, an arcuate cut-out adjacent the innermost end of the concave edge of said spiral element, and an arcuate edge connecting the outer end of said convex and concave edges of said element, the center of curvature of said arcuate edge being coincident with the center of curvature of said cut-out, said elements being arranged in nesting relation with each other and fixed together with the offset flange portion of each underlying the element next adjacent thereto to form a flat shroud, plate, the arcuate edge portions of the several elements defining a circular outer edge of the plate thus formed, and the arcuate cutouts defining a circular central hub receiving aperture, and a hub fixed in the aperture defined by said cut-outs, said other edge defining a strengthening rib for said crescent shaped element.

6. An impeller for a centrifugal pump comprising a plurality of one-piece crescent shaped elements, each of said elements having a flat portion defined by spiral convex and concave edges, each of said elements having a flange integral with and extending substantially normal to said flat portion adjacent to and substantially coextensive with one edge thereof, a second flange integral with and parallel to but offset from the flat portion of said element adjacent the other edge thereof, an arcuate cut-out adjacent the innermost end of the concave edge of said spiral element, an arcuate edge connecting the outer end of said convex and concave edges of said element, the center of curvature of said arcuate edge being coincident with the center of curvature of said cut-out, said elements being arranged in nesting relation with each other and fixed together with the oflset flange portion of each underlying the element next adjacent thereto to form a flat shroud plate, the arcuate edge portions of the several elements defining a circular outer edge of the plate thus formed and the arcuate cut-outs defining a circular central hub receiving aperture, a hub fixed in the aperture defined by said cut-outs, and a flat shroud plate fixed to the outer edges of the flanges on said elements, said plate having a central aperture formed therein, said other edge of said flat portion defining an elongated strengthening rib for said crescent shaped element disposed in position to substantially bisect said element.

7. For use in fabricating an impeller for a centrifugal pump, a one-piece crescent shaped element having a flat portion defined by spiral convex and concave edges, a flange bent from and extending substantially normal to said flat portion conicident with and substantally coextensive with one spiral edge thereof, and a second flange bent from said flat portion and extending parallel to but downwardly oflset from the flat portion of said element adjacent the other spiral edge thereof.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS King Feb. 14, 1905 Lawaczeck Feb. 4, 1930 5 Dodge Dec. 7, 1943 6 Troxler Nov. 1, 1949 J andasek Mar. 24, 1953 FOREIGN PATENTS Great Britain of 1901 Great Britain Mar. 22, 1934