US2789511A - Flexible vane pump impeller - Google Patents

Description

April 23, 1957 w. DOBLE FLEXIBLE VANE PUMP IMPELLER Filed May 25, 195s INVENTOR.

. WARREN DOBLE BY H/s ATTORNEY@ HARR/s, K/ecH, Fos Tena; Hake/5 2,789,511r FLEXIBLE VABIE PUMP IMPELLER Warren Doble, North Hollywood,l Calif., assigner, by

mesne assignments, to Jabsco Pump Company, Burbank, Calif., a corporation of California Application May 25, 1953, Serial No. 356,968

The present invention relates to a pump having an impeller of the flexible vane type, such as that disclosed and claimed in United States Patent Number 2,189,356,

`granted February 6, 1940, to Arthur M. Briggs, im-

pellers of this type ordinarily being formed in whole or in part of rubber, or similar elastomeric materials.

An impeller of the foregoing general character may be provided with exible vanes the outer ends of which are bulbous as viewed in a plane normal to the axis of rotation of the impeller, and a primary object of the invention in this conection is to offset the bulbous outer ends of the vanes in a direction opposite to the direction of rotation of the impeller. This construction has the effect of reducing the flexure of the vanes for a given thickness of the cam employed to flex the vanes, this reduction in vane llexure resulting in a material increase in the service life of the impeller, which is an important feature of the invention.

Another important object is to provide an impeller of the foregoing character having ilexible vanes provided with feathered edges engageable with the end walls of the impeller chamber of the pump, the feathered edges of the vanes lying on the neutral axes thereof, With conventional flexible vanes having unfeathered edges, flexure of the vanes by the cam produces what might be termed knuckles where the vane edges engage the end walls of the impeller chamber, such knuckles resulting from the fact that the fibers of rubber on the outer sides of the curves in the vanes are in tension while the bers on the inner sides of the curves in the vanes are in compression, which has the eifect of causing the rubber to expand axially with a resultant increase in friction between these knuckles and the end walls of the impeller chamber. Such knuckles have been found to be a source of internal leakage in pumps of this type. By feathering the vane edges, the present invention eliminates such knuckles since the neutral axes of the vanes are neither in tension nor compression when the vanes are flexed by the cam, the feathered edges, as hereinbefore indicated, lying on the neutral axes of the vanes. Such elimination of internal leakage by feathering the vane edges constitutes an important feature of the present invention.

Another important object of the invention is to provide the end faces of the hub of the impeller with a plurality of axially projecting ribs, each end face of the hub preferably having a plurality of annular and radial ribs forming a pattern somewhat similar in appearance to that of an ordinary wallie iron. This Waie iron configuration on each end of the impeller hub provides bafes to prevent internal leakage past the hub and also materially reduces friction between the end faces of the hub and the end walls of the impeller chamber, which are important features.

United States Patent "ice drawing and which is described in detail hereinafter. Referring to the drawing:

Figure 1 is a cross-sectional View of a pump incorporating the impeller of the present invention;

Figure 2 is a fragmentary sectional view taken along the arrowed line 2 2 of Figure l; and

Figure 3 is an enlarged, fragmentary sectional view taken along the arrowed line 3-3 of Figure 2.

In the drawing, the numeral 10 designates a pump housing which is provided with an impeller chamber 11v and which is provided with inlet and outlet ports 12 and 13 communicating with the impeller chamber, a cam 14 being provided between the inlet and outlet ports, as is conventional. Concentrically mounted in the impeller chamber 11 on a shaft 15 is an impeller 16 of the invention which is rotatable in the direction of the arrow 17, the impeller preferably being formed in whole or part of rubber, or a similar material, and including a central hub 18 having exible vanes 19 radiating therefrom. These vanes are flexed by the cam 14 as the impeller 16 rotates so as to pump iiuid from the inlet port 12 to the outlet port 13, as is well known in the art.

Considering the impeller 16 of the invention in more detail, the vanes 19 are provided with outer ends 23 which are bulbous, as viewed in a plane normal to the axis of rotation of the impeller, the bulbous outer ends, or bulbs, being offset laterally relative to the vanes 19 in a direction opposite to the direction of rotation 17 of the impeller, i. e., the centers of the bulbs being offset laterally relative to the radial center lines or Vneutral axes of the vanes in a direction opposite to the direction of impeller rotation. With bulbs 23 offset in this direction, the sides of the bulbs which engage the cam 14 do not project beyond, or project only very slightly beyond, the forward faces of the vanes 19. The effect of this construction is to materially reduce the amount of exure of the vanes, as compared to vanes having centered bulbs at their outer ends, as taught by the aforementioned Briggs patent, for example. In other words, it will be apparent that the iiexure of the vanes is reduced by an amount equal to the reduction in the amount which the bulbous outer ends project forwardly of the forward faces of the vanes 19. This reduction in vane flexure is quite important since, as hereinbefore pointed out, it adds materially to the service life of the impeller.

As best shown in Figure 3 of the drawing, the edges 24 of the vanes 19, which are engageable with the end walls of the impeller chamber 11, are feathered, or substantially feathered, the thickness of the edges 24 being very small as compared to the vane thickness. As hereinbefore discussed in detail, this has the effect of reducing friction and of eliminating or minimizing internal leakage between the edges of the vanes and the end walls of the impeller chamber, which are important features.

As best shown in Figure l of the drawing, each end of the hub 18 of the impeller 1611s provided with a plurality of ribs 2S and 26 which project axially of the impeller and which are engageable with the adjacent end wall of the impeller chamber 11, the ribs 25 being annular and the ribs 26 being radial in the particular construction illustrated. Also in the particular construction illustrated, the radial ribs 26 are shown as being, in effect, extensions of the feathered edges 24 of the vanes 19. The pattern of ribs 25 and 26 provides each end face of the hub 1S with a configuration similar to that of a waffle iron in the particular construction shown. However, different patterns of axially projecting ribs on the end faces of the impeller hub 18 might be employed, such as rib patterns resulting from dimples in the end faces similar to the `dimples in the surface of a conventional golf ball. In either event, the axially projecting ribs on the end faces of the impeller hub 18 act as baflies to preaffamati vent internal leakage past the hub and also reduce friction between the hub ends and the end walls of the impeller chamber, which are important features.

Although I have disclosed an exemplary embodimentl of my invention herein for purposes of illustration, it Will be understood that various changes, modifications and substitutions may be incorporated in such embodiment without necessarily departing from the spirit of the invention as delined by the claims appended hereto.

I claim as my invention:

1. A pump impeller having flexible elastomeric vanes which have neutral axes and the outer ends of which are bulbous when Viewed in a plane normal to the axis of rotation of said impeller, the centers of said bulbous outer ends being otset relative to the neutral axes of said vanes in a direction opposite to the direction of rotation of said impeller both when said vanes are flexed and when they are unexed.

2. In a pump, the combination of: a housing providing an impcller chamber and providing inlet and outlet ports which communicate with said chamber; a cam in said chamber between said ports; and an impeller concentrically located in said chamber and rotatable in a predetermined direction therein, said impeller having flexible elastomeric vanes which have neutral axes and the outer ends of which are engageable with the peripheral Wall of said impeller chamber and with said cam and are bulbous when viewed in a plane normal to. theI axis of rotation of said impeller, said vanes being flexed at least when said bulbous outer ends are in engagement with said cam, the centers of said bulbous outer ends being oset relative to the neutral axes of said vanes in a direction opposite to said direction of rotation of said impeller both when said vanes are lexed and when they are unliexed.

References Cited in the le of this patent UNITED STATES PATENTS 2,189,356 Briggs Feb. 6, 1940 2,258,371 Wernert Oct. 7, 194i 2,455,194 Rumsey Nov. 30, 1948 2,460,952 Simer et al. Feb. 8, 1949 2,466,440 Kiekhaefer Apr. 5, 1949 2,492,935 McCulloch et al. Dec. 27, 1949 2,499,163 Rand Feb. 28, 1950 2,542,268 Weyer Feb. 20, 1951 2,599,600 Arnold June l0, 1952 2,644,402 Lehman July 7, 1953 2,648,287 Thoren et al. Aug. 11, 1953 2,663,263 Mayus et al. Dec. 22, 1953 2,664,050 Abresch Dec. 29, 1953 FOREIGN PATENTS 244,826 Italy Feb. 27, 1926

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