US2948227A

US2948227A - Pump

Info

Publication number: US2948227A
Application number: US774972A
Authority: US
Inventors: Richard S Neely
Original assignee: Lord Manufacturing Co
Current assignee: Lord Manufacturing Co
Priority date: 1958-11-19
Filing date: 1958-11-19
Publication date: 1960-08-09
Anticipated expiration: 1977-08-09

Description

Aug. 9, 1960 5, NEELY 2,948,227

' PUMP Filed NOV. 19, 1958 I IN V EN TOR. W5 BY FIG 5 if? I @2231,

. f' Patented Aug. 9, 1960 United States invention is a rotary pump having a pump hens-- mg with end ,walls whose axial separation varies from a at one side to a maximum at the'opposite side of the axis of rotation- The impeller'has axially projectingflexible, blades confined between the end walls. At low speeds, the blades are flexed axially to vary the volume between adjacent blades and produce positive displacement'pumping. 'At higher speeds, the blades are flexed by the fluid pressure away from contact with the housing end walls and a centrifugal pumping action 'is obtained.

In the drawings, Fig. 1 is an end view of an impeller; Fig. 2 is a section of line 22 of Fig. 1; Fig. 3 is an end view of a pump housing; Fig. 4 is a section of line 4-4 of'Fig. ,3; Fig. 5 is a diagrammatic perspective illustrating the position of the impeller blades during low speed pumping; Fig. 6 is a view similar to Fig. 2 but with the blades ofunequal axial projection on opposite sides of the center disc; and Fig. 7 is an edge view. of an imthe impeller from the suction side and in a similar manrotate from point 22 to point 23 in a clockwise direction, the blades are continually expanding axially thereby increasing the volume of the space between adjacent blades and creating a suction at the inlet 20. As the impeller rotates-from .point 23 to point 22, the blades are confi tinually being compressedaxially thereby reducing space between adjacent blades and forcing liquid out the outlet 21; It will be noted that on the pressure side of point 22 there is a pair of blades designated by the numerals 24 and which at all times seal the pressure side of ner on the suction side of point 22

blades

25 and 26 seal the liquid pressure from the inlets 20. As the impeller rotates from the position illustrated in Fig. 3, the space between the two

blades

24 and 25 continues to decrease until the blade 25" reaches point 22 and any pressure built up between the blades is relieved by flexing of the blade 24. Asthe blade 25 passes point 22, the blade 26-sta1'ts to pass over the suction inlet 20 and the suction created by the gradual increase of the space between the

blades

25 and 26 draws liquid into the inlets 20. Because of the

blades

24, 25 and 26, it is not possible at any time for liquid to flow from the pressure side of illustrated in the perspective view of Fig. 5.

peller having blades of configuration for improved stress distribution.

The pump impeller has a metal hub 1 fixed to a drive shaft 2 and bonded to the center of a rubber disc 3 carrying'integral axially projecting rubber blades 4 on opposite surfaces. The shaft 2 is journaled in

opposite end walls

5 and 6 of a, Pump housing 7 and is provided with suitable seals 8. Surrounding the shaft, 2 are axially projecting rubber sleeves 9 and 10 integral with the impeller which fit in recesses 11 and 12 of the

end walls

5 and 6. The sleeves 9 and 1 0 rotate with the impeller and provide seals which increase in effectiveness during rotation due to the effect ofcentrifugal force which causes a slight expansion of thesleeves. The sealing action of thesleeves 9 and 10 is adequate for most applications so that the seals 8 may be omitted. :The housing end walls Sand 6 have integral tubular projections 13 and 14 which are received in slots or

notches

15 and 16 in the blades 4 and which provide flexible

outer sections

17 and 18 on the blades which are free to flex without stressing the disc 3 or the bonded connection to the hub 1. The blades 4 have the same diameter as the disc 3 and make sliding engagement with the outer peripheral wall 19 of the pump housing and also with the outer surfaces of the projections 13 and 14 which may be considered as the inner peripheral wall of the pump housing. The parts so far described are all concentric with the pump shaft 2.

The pump housing has two inlet connections 20, respectively on the upper and lower sides of the disc 3, and has two outlet connections 21 which are on the upper and lower sides of the disc. As shown more clearly in Fig. 4, the end walls '5 and 6 of the pump housing lie in planes which are inclined to each other and to the axis of the pump shaft. Accordingly, as the impeller rotates at low speeds, the blades 4 are compelled to flex axially. The point of separation between the

end walls

5 and 6 of the pump housing is designated by the numeral 22 and the point of separation is designated by the numeral 23. As the impeller blades point 22 to the inlets 20.

The flexing of the impeller blades 4 is diagrammatically In this figure, unstressed positions of the blades is designated by the numeral 27 and the planes of the

end walls

5 and 6 of the pump housing are designated by the numerals 28 and 29. Fig. 5 shows the position of the blades at slow speed rotation of the impeller. At higher speeds,

the liquid pressure on the leading face of the blades a the pump for pumping liquids from two separate sources.

Whenthe disc issymmetrically located with blades of equal, projection on opposite sides, the pumping cavities will have equal capacity. By having the blades 4a on one side of the disc 3 of greater axial projection than blades 4b on the other side of the disc as shown in Fig. 6, the pumping cavities will have unequal capacity. Inequality of pumping capacity may also be obtained by having one of the end walls of the pump housing at a different inclination than the other.

By having the blades on opposite sides of the center disc 3, axial bending forces on the blades are balanced against each other. Radial bearing loads are eliminated because the blades are concentric with the pump shaft. Many of the stresses present in pumps with radially defleeting blades are accordingly eliminated. The design permits very uniform stressing of the impeller blades which means that without exceeding the operating stress, the amount of flexing of the blades can be increased with the resultant increase in pump capacity which is directly proportional to the amount of flexing of the blades. The blade configuration shown at 30 in Fig. 7 is preferable because the section 31 subject to the greatest bending moment has the greatest cross section.

It is not necessary that the disc 3 be circular so as to divide the pump housing into two separate pumping cavities. The disc can be cut away between adjacent blades, for example, by notches extending inward from the periphery of the disc so there will be only a single pumping cavity between adjacent blades. With the disc cut away, the same kind of pumping action will be obtained as the blades are axially flexed but, of course,

fluid can be pumped only from a single source because the disc will no longer block free fluid communication between its upper and lower sides. Since the disc acts as part of the structural support for the blades, it is advantageous to keep the part of the disc immediately adjacent the blades and hub as a structural part.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A rotary pump having a housing with end Walls having an axial separation which varies angularly about the axis of the pump from a maximum to a minimum and back to a maximum, a rotary impeller having a hub at the center, a tubular sleeve of flexible material united to the impeller concentric with and projecting axially from the hub, a plurality of angularly spaced flexible blades carried by the hub and bridging the space between the end walls and being deflected axially to change the volume between adjacent blades as the impeller is rotated, said blades having notches radially outside and adjacent said sleeve, said housing having a tubular projection radially outside and telescoped over and making sealing engagement with said sleeve and complementary to and received in said notches, and an inlet on the side of the housing in which the volume between adjacent blades is increasing and an outlet on the side of the housing .in which the volume between adjacent blades is decreasing as the impeller is rotated.

2. A rotary pump having a housing with end walls having an axial separation which varies angularly about the axis of the pump from a maximum to a minimum and back to a maximum, and a rotary impeller having a hub at the center carrying two sets of angularly spaced flexible blades extending between the hub and the pe riphery of the impeller and with each set of blades projecting axially into engagement with a different end wall, each blade having an axially extending notch at its inner end, said housing having axially inward extending tubular projections complementary to said notches and extending from opposite ends of the housing into said notches, said impeller having tubular sleeves radially inside said tubular projections and projecting axially outward from the impeller and having outer ends telescoped in sealing engagement into said tubular projections of the housing, and said blades bridging the space between the end walls and being deflected axially to change the volume between adjacent blades as the impeller is rotated, and an inlet on the side of the housing in which the volume between adjacent blades is increasing and an outlet on the side of the housing in which the volume between adjacent blades is decreasing as the impeller is rotated.

3. A rotary pump having a housing with end walls with an axial separation a minimum at one point around the circumference of the housing, a rotary impeller having a hub at the center between the end walls and carrying two sets of angularly spaced flexible blades, each set respectively projecting axially into engagement with a different end wall, said blades bridging the space between the end walls and being deflected axially to change the volume between adjacent blades as the impeller is rotated, said blades having at their inner ends notches extending axially inward from the end walls of the housing, said housing having axially inward extending tubular projections complementary to the notches and extending from opposite ends of the housing into said notches, said im: peller having tubular sleeves radially inside said tubular projections and projecting axially outward from the impeller and having outer ends telescoped in sealing engagement into said tubular projections of the housing, and an inlet communicating with the housing on the side of said point in which the volume between adjacent blades is increasing as the impeller is rotated past said point and an outlet communicating with the housing on the side of said point in which the volume between adjacent blades is decreasing as the impeller is rotated past said point.

4. A rotary pump having a housing, a rotary impeller having a plurality of angularly spaced flexible blades with a sliding fit in the housing, said housing having a region of minimum axial length whereby the blades are deflected axially to change the volume between adjacent blades as the impeller is rotated past said region, said impeller have ing at its center flexible sleeves with free ends projecting axially in opposite directions, said housing having tubular projections radially outside and telescoped over said sleeves and making sealing engagement therewith, said blades having'notches radially outside said sleeves and complementary to and receiving said tubular projections, and an inlet communicating with the space between the blades on the side ofsaid region in which the volume between adjacent blades is increasing as the impeller is rotated past said region and an outlet communicating with the space between the blades on the side of said region in which the volume between adjacent blades is decreasing as the impeller is rotated past said region.

References Cited in the file of this patent UNITED STATES PATENTS 2,533,399 Sad-let et a1 Dec. 12, 1950' 2,542,240 Fernstrum Feb. 20, 1 951 2,542,268 Weyer Feb. 20, 1951 2,573,819 Weyer Nov. 6, 1951 2,605,715 Brant Aug, 5, 1952 2,649,052 Weyer Aug. 18, 1953 2,711,136 1 Arnold June 21, 1955 2,734,457 Fernstrum Feb. 14, 1956 2,853,021 Doble Sept. '23, 1958 2,858,769 Doble Nov. 4, 1958 2,881,710 McLean Apr. 14, 1959