US2165808A - Pump rotor - Google Patents

Description

PUMP 5010a Filed May 22, 1937 ATTORNEYS Patented July 11 1939 UNITED STATES PATENT OFFIHCE PUMP ROTOR Daniel Murphy, New Castle, Pa. I Application May 22, 1937, Serial No. 144,136 Claims. (oi. 103-115 My invention relates to rotary pumps, particularly to pumps for heavy liquids, such as slip used in the manufacture of pottery and chinaware; More particularly, the invention relates to the vaned impellers of such pumps, and consists in specific refinements in the design of the impeller vanes, to the end that greater efficiency in pump operation shall be realized.

' In the accompanying drawing Fig. I is a view in front elevation of the vane-carrying face of an impeller embodying the invention, and Fig. IIv is a view of the impeller in side elevation. Fig. III is a fragmentary view of the impeller in modified or elaborated form, the impeller appearing partly in front elevation and partly in vertical section, Fig. IV is a fragmentary sectional view of. the modified impeller, taken on the plane IV--IV of Fig. III. And Fig. V is a fragmentary view, showing the impeller of Fig.

'20 I 'to larger scale and illustrating in detail the particular form in which the vanes are constructed.

The impeller of this invention consists in a body I, in the form of a thin circular disc, carry- 25 ing a plurality of (in this case four) involute vanes 2. The body I is provided truth the usual central hub 3, by means of which the impeller is mounted upon and secured to the usual rotary shaft of a pump. The body I, vanes 2, and hub 30 3 may, as here shown, be integrally cast of steel .or other suitable metal. In service the impeller is rotated in an involute chamber of known sort in the body of a pump, and the side edges 2a of the vanes, positioned laterally outward from 35 the disk-like body I, cooperate with the side wall of such chamber, as described in my co-pending application for patent, Serial No. 138,806, filed April 24. 1937, now Patent No. 2,128,496, dated August 30, 1938. As shown in such patent, a 40 wearing plate or ring may be embodied in the side wall of the chamber for immediate cooperation with the edges of the vanes. In operation, the rotating impeller draws liquid into the impeller chamber, through an inlet opening through 45 the side wall (or wearing plate) of the chamber. This inlet is concentric with and encircles the impeller shaft, and the liquid being pumped, upon flowing into the chamber in a.direction paralleling the axis of the shaft, moves radially into the passages P between the impeller vanes 2. whence in known way it moves under the influence of centrifugal force to the outer ends of the passages and into a discharge duct that opens into the peripheral wall of the pump w chamber.

The form of the impeller vanes, or the form of the passages P between the vanes, as viewed on a plane normal to the axis of impeller rotation (Fig. I), is of prime'importance to pump efiiciency, and it is to this detail of impeller struc- 5 ture that my invention is directed.

It will be perceived that each of the vanes 2 extends from its inner end on a multiple-radius curve to the periphery of the body I, Considering Fig. V, it will be understood that the two 10 ends of each curved vane lie on diametrically opposite sides of the axisa of the impeller, and it will be noted that the curved extent of the vane is through substantially 180 angular degrees with respect to such axis or center of the- 15 impeller. The area of the inlet end of each passage P between the vanes is greater than the area of the outlet end-a comparison of the dimension b with dimension 0 in Fig. I will serve diagrammatically to indicate the relation of the areas. The cross-sectional area of each passage P decreases progressively from its inlet (b) to a point ((1) Save in the relatively short portion of the passage where the area progressively decreases from value b to d, the cross-sectional area of the passage ,is substantially uniform; that is, throughout the greater portion of the length of the passage the inner curved face I of one vane extends in substantial parallelism with the outer curved face if of the next adjacent vane. As shown in the drawing, and as will be perceived upon a consideration of the following specification, the gradual decrease in the effective area of passage P immediately inward from itsinlet b is obtained by forming the inner ends of the vanes on relatively acute curvature-- on a radius that is relatively small with respect to the radius or radii on which the main body portion of the vane is curved.

Turning to Fig. V, I shall describe in exemplary way how the curvature of one of the four identical involute or multiple-radius vanes of the impeller is developed. In the case chosen for illustration, the diameter of the discular body I is 61 that is, the effective radius from the center of the' impeller to the outer tips of the vanes is 3 A square 4 is scribed on the plane face of the body I, and the size and position of the square are such that the four corners of the square lie in a circle 5, 1 in diameter and concentric with the axis a of the impeller. A second circle 6 is scribed, this second circle being 2" in diameter and concentric with the first.

I At an interval of A" below the corner 40' of the square 4, and at an interval of V4," above the 56 corner 42 of. the square, a diametrical line D is laid out. The outer surface if of the vane comprises a succession of circular arcs a, b, c, and d. More specifically, using the corner 4i of the square as a center, an are I) is struck on a radius of 11%"; the arc extends from a line 4H1 (line 4I0 comprising a continuation of one side of the square 4, as shown) to a line 400, lying at an angle of 50 degrees from line 4H]; and, from the point of intersection of the are I) with the line 400, an are a is struck. The center of are a lies at the point of intersection of line 400 with the circle 6, and the radius of such are will be found to be about From the point of intersection of are 1) with line 4H), the outer surface of the vane is continued on arc c, which has the corner 42 of the square 4 as a center, and a radius of substantially 2 The are 0 extends through degrees to a line 420 that comprises a projected continuation of the lower side of the square 4, and the remaining portion of the outer surface of the vane continues from the line 420 on an arc d. The radius of the are d is in this case the radius of the impeller body I, and its center is the center a of the impeller. In length the arc extends from the point of intersection with line 420 to a point I lying below the diametrical line D.

The radially inner passage forming surface of the vane is defined by three arcs: An arc struck about center 4|, on a radius of 1%", and extending from the line 4|[I to the circle 6; an arc struck about center 42, on a radius of substantially 25' and extending through 90 from line M0 to line 420; and an arc struck about the corner 43 of the square 4 as a center, on a radius of substantially 3%", and extending from line 420 to a point 4' below the diametrical line D. At the opposite ends of the vane, the inner and outer surfaces and ff are united on small radii 8 and 9, respectively. Upon visualizing how I derive the shape of one vane, it will be readily understood how all four of the identical vanes are provided in equally spaced relation on the face of body I.

It may be noted that all of the centers of the several radii employed in generating the inner and outer surfaces of the vanes 2 lie relatively near the center of the impeller, and, as a matter of definition, it may be said that all of such centers lie within an area defined by a circle l0 concentric with the axis a of the impeller and having a radius R equal to, or less than, one-half of the effective radius of the impeller, in this case the value of R being 1 I have indicated in dotted lines in Fig. V a portion of one of the three other vanes organized on the body I with the vane shown in full lines. It will be noted that throughout its arcuate extent 0' the body of the vane shown in dotted lines has common center with the arc b through which a portion of the body of. the vane shown in full lines extends. square 4 provides the center of the arc b of the full-line vane and the center of the are c of the dotted-line vane. Thus, it will be understood that one of the radii of curvature of one vane on the body i has common center with one of the radii of curvature of the next adjacent vane. In this manner, I provide throughout a relatively great extent of the passage P between the vanes, a substantially uniform cross-sectional area, this feature of my impeller structure having been mentioned above.

In the ensuing claims X is used to represent That is, the corner 4| of the the value of the radius (1%") on which the inner end portion of, each vane extends through substantially 90 in clockwise direction from the line M0; Z is used to represent the value of the radius (2 on which the medial portion of each vane extends through 90 in counter-clockwise direction from the line 410; Y is used to represent the radius (3%") on which the outer tip of the vane extends counter-clockwise through a relatively small angle from the line 420; and as shown in Fig. V, R represents the value of the radius of circle 10, within which the centers of the several vane radii lie.

I have obtained notably good results with pumps employing my impeller. For example, by operating an impeller of the size specified above, at a speed of 1,750 R P. M., I have obtained 26" of mercury suction at the intake of the pump, and 30 pounds pressure in the discharge line. As those skilled in the art will appreciate, this is an exceedingly efficient performance.

In elaboration of the impeller already described, I provide an annular series of relatively short blades 20, spaced apart peripherally of the impeller, and severally inclined to radial lines 2| of the impeller, as indicated in Fig. III. The body l of. the impeller is formed on larger diameter, to extend radially outward ,from the outer tips of the vanes 2, and provide support for the blades 20. In still further refinement, I 3

provide an annular Wall portion 22, paralleling the discular body I, and spaced axially therefrom such an interval that the face 22a of the annular portion 22 lies in common plane with the side edges 2a of the vanes 2. Note Fig. IV. The

entire structure may be and advantageously is formed in a single, integral metal casting. Other than as illustrated and described, the modified impeller of Figs. III and IV is identical with the impeller first described. The modified or elaborated impeller operates with higher efficiency in pumping lighter liquids than the heavy slip" for which the first-described impeller was particular y designed, but it is to be understood that either form of the impeller described, or any impeller embodying the invention defined in the appended claims, may be used with good results in pumping either heavy or light liquids.

I claim as my invention:

1. A pump impeller comprising an impeller body carrying a plurality of vanes extending outward with respect to the axis of said body on multiple-radius curvature and forming between them passages for fluid, said impeller body having a diameter of. the value of D, and the curvacomprising an impeller body including a plurality of involute vanes each having an inner end located eceentrically of the axis of the impeller and extending outward with respect to such axis on multiple-radius curvature and forming between them passages for fluid, said passages having inlets formed between the inner ends of the vanes and outlets between the outer ends thereof, each of said vanes lncluding an inner end portion extending through a relatively short arcuati, distance on a radius of the value of X, and a portion extending outward from such end portion through a relatively great arcuate distance on a radius of the value of Z, the outer ends of the vanes lying in a circle whose diameter has a value of D; said values bearing the relation to one another as they bear when D equals 61%, X equals 1%", and Z equals 21- 5; whereby the cross-sectional area of each of said passages gradually decreases in a region extending immediately from the inlet of the passage outward through a relatively short arcuate interval, the cross-sectoinal area of such passage being of substantially uniform value through a relatively long curved interval from such region outward to the outlet of the passage, said passage having at all points in its extent a cross-sectional area less than the area of said inlet, and having at no point a cross-sectional area appreciably less than that in said relatively long curved portion that extends between said inner region of the passage and said outlet.

3. An impeller for a rotary pump, said impeller comprising an impeller body including a plurality of involute vanes each having an inner end located eccentrically of the axis of the impeller and extending outward with respect to such axis on multiple-radius curvature and forming between them passages for fluid, said passages having inlets formed between the inner ends of the vanes and outlets between the outer ends thereof, each of said vanes including an inner end portion extending through a relatively short arcuate distance on a radius of the value of X, and a portion extending outward from such end portion through a relatively great arcuate distance on a radius of the value of Z, the outer ends of the vanes lying in a circle whose diameter has a value of D, the centers of the said two radii being eccentric with respect to one another and lying within a circle having a radius of the value of R; said values bearing the relation to one another as they bear when D equals 6 X equals 1%", Z equals 2 and R equals 1 whereby the cross-sectional area of each of said passages gradually decreases in a region extending immediately from the inlet of the passage outward through a relatively short arcuate interval, the cross-sectional area of such passage being of substantially uniform value through a relatively long curved interval from such region outward to the outlet of the passage, said passage having at all points in its extent a crosssectional area less than the area of said inlet,

and having at no point a cross-sectional area appreciably less than that in said relatively long curved portion that extends between said inner region of the passage and said outlet.

4. An impeller for a rotary pump, said impeller comprising an impeller body including a plurality of involute vanes each having an inner end located eccentrically of the axis of the impeller and extending outward from such inner end on' a curve comprising a series of arcs, the curvature of said vane being most acute in the inner end portion of the vane and such inner end portion extending through an angle of substantially 90 degrees with respect to a center of curvature, the radii of said series of arcs being of successively increasing value outward from said inner end portion of the vane and the entire vane extending from end to end through an angle of approximately 180 degrees, involute passages for fluid between said vanes, said passages having inlets formed between the inner ends of said vanes and outlets between the outer ends thereof, each of said passages having a cross-sectional area that gradually decreases in a region extending immediately from the inlet of the passage outward through a relatively short curved interval and that is of uniform value through a relatively long curved interval extending from such region outward to the outlet of the passage, said passage having at all points in its extent a crosssectional area less than the area of said inlet, and having at no point a cross-sectional area appreciably less than that in said relatively long curved portion that extends between said inner region of the passage and said outlet.

5. An impeller for a rotary pump, said impeller comprising an impeller body including a plurality of involute vanes each having an inner end located eccentrically of the axis of the impeller and extending outward from such inner end on a curve comprising a series of arcs, the curvature of such vane being relatively acute in a relatively short curved portion that extends from the inner end of the vane through an angle of substantially 90 degrees with respect to a center of curvature, said relatively short acutely curved portion of the vane merging with a relatively long vane portion that is less acutely curved, said relatively long vane portion extendingi'rom said acutely curved portion through an angle of approximately 90 degrees with respect to a second center of curvature, involute passages for fluid between said vanes, said passages having inlets formed between the inner ends of said vanes and outlets between the outer ends thereof, each of said passages having a cross-sectional area that gradually. decreases ina region extending immediately from. the inlet of the pas-q sage outward through a relatively short curved interval and that is of uniform value through a relatively long curved interval extending from such region outward to the outlet of the passage, said passage having at all points in its extent a cross-sectional area less than the area of said inlet, and having at no point a cross-sectional area appreciably less than that in said relatively long curved portion that extends between said inner region of the passage and said outlet.

DANIEL MURPHY.

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