US2899902A - Rotary pump impeller - Google Patents

Description

Aug. 18, 1959 J. c. BANDLI ETAL ROTARY PUMP IMPELLER Filed April 4, 1957 INVENTOR. f Bfl/VDA/ :A M 2 .r F @h/J/V/ x, 5

United States Patent ROTARY PUMP IMPELLER Application April 4, 1957, Serial No. 650,711

3 Claims. (Cl. 103-117) This invention relates generally to rotary pumps and impellers therefor of the flexible vane type.

The principal object of the invention is to provide an impeller adapted for incorporation in a rotary pump such as used to circulate the cooling fluid in an outboard motor, which impeller is so constructed as to provide effective service for longer periods of time than heretofore known impellers.

A more specific object of the invention is to provide an impeller of the flexible vane or blade type wherein the blade will maintain a constant width and thickness throughout extended use in a bent condition so as to neither diminish the seal provided by or increase the interference incurred by the blade lateral edges in contact with the pump housing walls.

Another object of the invention is to provide a flexible blade impeller wherein the blades thereof will resist the taking of a permanent set in their flexed condition to thus preserve the seal between the end edge of blades and the pump housing wall.

Still another object of the invention is to provide an impeller for a rotary pump wherein the impeller has a continuous rib on the side wall thereof for providing a seal between the impeller drive shaft and the side wall of the pump housing and with the rib so formed as to be lubricated by the fluid pumped to thus resist wearing out and preserve its sealing engagement.

Still another object of the invention is to provide an impeller of flexible resilient material mounted on and bonded to a metallic hub and wherein the impeller and hub are so formed as to provide an improved bond there between which prohibits any separation or looseness between the two even after the greatest periods of use to which such an impeller is normally subjected.

With these objects in mind the invention broadly comprises a flexible vane impeller adapted to be mounted on a drive shaft for rotation in an eccentric position in a rotary pump housing, said impeller having a body portion of flexible resilient material bonded to a central metallic hub adapted to be keyed to the drive shaft, the body having a plurality of circurnferentially spaced blades extending outwardly therefrom for endwise engagement with the cylindrical Wall of the housing, said blades being of constant width and thickness throughout their outward extension and having a relatively thin thickness for ready flexibility, and a plurality of circumferentially spaced backing teeth extending outwardly from the body in substantially radial directions, one tooth located immediately behind each blade relative to the direction of rotation to stiffen the blade, each of said teeth being tapered in its extension from the body and being spaced, throughout substantially the entire length of its extension, away from the blade it follows.

The invention is further characterized by the provision of a continuous serpentine rib or vane on each side of the body adapted to encircle the drive shaft and provide a seal between the shaft and pump housing side wall. The central metallic hub of the impeller has a plurality of circumferentially spaced transverse bores which are filled with integral portions of the body to provide a secure bond between the hub and body.

The aforementioned and still additional objects of the invention will be brought to light during the course of the following specification reference being made to the accompanying drawing in which- Fig. 1 is a plan view of a rotary pump housing with.

the near end wall or pump cover removed and with the drive shaft shown in section and the impeller in operative position within the housing.

Fig. 2 is a transverse sectional view of the pump taken on line 22 of Fig. 1 with the pump cover in place.

Fig. 3 is a slightly enlarged plan view of the impeller removed from the pump housing.

Fig. 4 is a transverse section through the impeller taken on line 4--4 of Fig. 3.

Fig. 5 is a partial longitudinal section through the impeller taken perpendicular to the turning axis thereof and showing the bonding connection between the hub and body of the impeller.

Referring now more particularly to the drawing reference numerals will be used to denote like parts or structural features in the different views. In Figs. 1 and 2 the numeral 10 denotes generally a housing for a rotary pump. The housing has a shallow cylindrical shape with an end wall 11 provided with a centered opening 12 for reception of the drive shaft 14, such as the vertical drive shaft of an outboard motor. The circumferential Wall of the housing 10 is denoted at 15 and has a varying thickness with the interior annular surface 16 thereof disposed eccentrically with respect to the opening 12 and drive shaft 14. The housing is provided with circumferentially spaced apertured mounting ears 17 and has a.

recessed annular shoulder 18 former on the open side both of which are adapted for connection with fluid lines for free passage of fluid through the chamber 21.

An impeller 25 is mounted on the shaft 15 for rotation within the chamber 21 to force the fluid therefrom. This impeller generally comprises a hub 26 of hard, preferably metallic, material and an impeller body 27 formed of flexible resilient material such as rubber or plastic.

Hub 26 is an annular sleeve having an internal key 23 adapted to mate with a slot in shaft 14. to lock the hub to the shaft for rotation therewith. The hub has an axially reduced peripheral portion or rim 29. This rim is provided with radially extending lugs 30 spaced circumferentially around the hub. These lugs are transversely apertured as at 31. The aperture may be omitted in lug 30 opposing key 28 for greater hub strength at that point.

The impeller body is designated generally by the numeral 34. This is a unitary body of flexible resilient material such as neoprene rubber having a central portion 35 which is molded over and around the periphery of hub 26. It will be noted in Figs. 4 and 5 that the central portion 35 of the body is greater in transverse thickness than the hub rim 29 so as to completely surround the radially therefrom are a plurality of circumferentially spaced projections or teeth 36 which are of constant width but which taper in their radial extension. These Ice Patented Aug. 18, 1959 aesaaoa 3 projections'are"ofsubstantially the same width as the hub 26'-which-isconsiderably less than -the=distance*between opposing faces of housing walls 11 and 19 whereby when the impeller is disposed within the housing 10 there is substantial clarance-betweenthewalls and the projec-- tions: The projections-36'- are preferably radially aligned with lugs 30 on thehub-"for'rnaximumstrengthofthe bbnd hetween the body and hub 'agai-nst'separationcaused by stressing of the projections 36;

The impeller vanes orblades-are-designated atST and I extend outwardly from the'impeller body portion'35 in-a' tangential directionrelative to the shaft 142: These vanes are preferably flat with the-broadfaces thereoflying on planes-whichareparallel to the-turning axis; Each vaneis spaced just ahead ofa toot-1166 as-denoted at=38-'withtHe facing' surfaces of each-vane andits' back'up tooth being-parallel: Thervane 37 is" somewhat wider' and" longer 'than-its back uptooth 36. It isalso a-bit wider than the space between the housing end walls 11 and'19- sor-asto be slightly compressed therebetweenwhen in operative position within the housing.-

At each'sidethereof the impel-lerbody34 is provided withan' axiallyprojecting continuous rib 39 adapted toencircle the driveshaft 14'and provide a seal betweenthe shaft and the outer portions of the pump compart ment. These ribs project transversely to the-'width-of vanes=37and connect -to the inner ends'thereof as shown iii-Figs; l and 3.

In their continuous extension around'the shaft'receiw irlgimpeller opening each rib 39- has an irregular or wavy" configuration which-might hardened to as serpentine with the blades 37 joining'the ribs at theoutsidecurves remote from the'centeraxis. The purpose .of'the ser p entine'configuration best showninFigs. 1 and3 will be presently understood;

In operation inthe pump'the'impeller'is mountedon?v thedrive shaft 14 and positioned within, the'housing'- as shownin Figs; 1 and 2'. The shaft isdriven to rotate the impellerin the direction'ofthearrow inFig; 1' and. with the eccentricity of the impellcr the 'cooling .fluid" is forced" through the housing.

It'will be understood that'the vanes *37 being relatively thinthroughout their length will flex very easily and are accordingly adapted to use OVGI'IGXtCHdGd periods Without "breaking or taking a permanent .set in. a;trailing' di' rection'; The projections or'teeth36 serve as backup lugs for-the vanes'37 andstiflten the vanes'so that'they will be held firmly against the wall. 16 as they are rotated; for positive fluid displacement. These. teeth extend. a di'stancesomewhat less than the maximum radius of'the. pumpchamber; Thus 'while'the tip ends of teeth 361Will'. flex" as they move along the nearportionof wall 16 they" will straighten out again as theymove along the far 'portion ofthe wall, reducing the possibility of theirtakingi a permanent trailing set..

The lateral edges of.vanes 37 are in sealing engagement with walls 11 and 19 and the vanes are actually compressed between the walls to assure constant contact;

The thinness of the vane reduces to a minimum anyvariance of .width of the vane along its length as the vane is flexed. This is important in preserving the lateral sealing efiectiveness of the vane without increasing interference with the housingend walls.

The serpentine sealing rib 39 has a significant advantage over a circular. rib in that all but theinnermost crest. portions thereof will pass along areas of.side.walls 11' and 19 which have intermittentlybeen exposed to water. The major portion of the rib sealing surface is accordingly being constantly lubricated to decrease its susceptibility to. burning out through constant friction. Also the irregularity of the ribs prohibit the wearing of. circular. grooves in the pump housingend walls after. extended use.

Thestrengthof the bond provided by the interlocking constructiombetweenthe hubLZfi .and impeller body 34 wilLbe readily appreciated. The construction disclosed.

4.. accordingly economically and effectively carries out the aforementionedpbjectives:

It is understood that suitable modification may be made in the structure as disclosed, provided that such modifications come within the spirit and scope of the appended claims. Having now therefore fully illustrated and described the invention, whatwe claim to be new and desire to protectlbyiIietters Patent ist:

1. In a rotary pump of the character described, a. housing providing" a pump chamber" havingtparallel .end walls connectedbyj'a circumferential Wall, .a rot-arydrive shaft extending through the chamber. end-walls andbeifig eccentrically disposed with respect to the cylindrical wall, an: impeller of molded material capable: of being deformed disposed. within thecharnberand mounted on said drive shaft for rotation therewith, the impeller having a central mounted portion and a plurality of flexible vanes extending outwardly from the mounted portion for constant endwise' engagement with the circumferential. wall so that the vanes will bendsubstantiallytinatrailifrg direction as they'passialongj the eccentricallynearpprtion of the cylindricalwall, said vanes'havinga normal" width greater than the-distancebetweentthe'end wallsso as to be held'under compression therebetween; andthe' impeller having a plurality of integralbackirig teetlr'erF tending radially outward from the. centralportibn to? a" point adjacent the .tips ofsaid"flexible vanes=onet of said teeth Being-immediately behindeachvane relativetorthe." direction ofrotation of the impeller'tostiflen'the'vane as" it is'bent in..a' trailingj direction, said"teeth.being"spaced from saidlvanes when'saidwanesare; in nOIll-fiGXTPOSF- tion and narrower than'the distance "b'etween'thechamber' end walls and beingradially taperedin thickness in their outward extension.

2'. An impeller for use in. a rotary" pump havinggat drive shaft comprising an annular metal hub formount-l ing on the shaft, a unitary impeller body ofresilient deformable materialhaving a central portion molded on the huh and aplurality of circumferentially spaced. projections extendingfrom the .centralpprtion' irr'radial directions relative to the hub and adapted" to he longi tudinally flexed'during operation of the impeller, the hub" having a .plurality of circumferentiallyspaced radiallyextending lugs projecting from theperiphery th'ereof one' into each impeller bodyprojection,.the.majorityofifsaid" lugs having apertures extending .therethrough' in'axialdirections with respect'to the hub, and .said impellerlbodyf material being formedto surround. said'lu'gs .andto'fil'l. said lug apertures with the body and Ilugs'beingb'ondedl togetherthroughout their coextensive surfaces to resist separation of impeller body from the hub. in the'areasiof the projections.

3.. In" a rotary, pump, of .the charatcer descrihed,'j a. housing providing, a pump chamber haVingparaHeFend walls connected by a circumferential"wall; arotary dfive shaft extending through the chamberend walls and. being; eccentrically dis'posed .with'. respect to the cylindrical wall; an annular'hub mounted on. the shaft, an impeller body, of molded material capable of being deformed"disposed within the chamberand'mountedion said .hub forlrota tion. therewith, the impeller: body having a central' counted portion and'a plurality of flexible vanes extend ing outwardlyffom themounted portionfor constant endwise engagement with the circumferential 'wallLso that" the. vanes willlbend'substantially in a tr'aili'ngjdirection: as. they pass alongthececcentrically near portionoffthe' cylindrical wall, said vanes having a normal width greater than the distance hetween the end walls so asto beheld under. compression therebetween, aplurality ofbacki'ngi? teeth extending integrally outwardrfr om the central-poi tion to points adjacentv the tips of said"fl'exible;vanes and said teeth beingspacedfone immediately behin'cl'each vane relative to the direction of rotation. of theimpellerf toengage. and stiife'n the vane as it is'bentdn'a trailing direction, said teeth beingrspacedifromhsaid'vanes when:

said vanes are in non-flexed position and being narrower than the distance between the chamber end walls, the impeller body and hub being bonded together throughout their coextensive surfaces, and the hub having a plurality of circumferentially spaced radially extending lugs projecting from the periphery thereof one into each of said backing teeth to increase the areas of bond near the teeth.

References Cited in the file of this patent UNITED STATES PATENTS Wernert Oct. 7, 1941 15 6 Simer et a1. Feb. 8, 1949 Kiekhaefer Apr. 5, 1949 Fernstrum Feb. 20, 1951 Weyer Feb. 20, 1951 Parrish Nov. 4, 1952 Smyser Apr. 28, 1953 Smyser Apr. 28, 1953 Abresch Dec. 29, 1953 Kemp July 20, 1954 Smith Apr. 9, 1957 Wakeman Aug. 26, 1958 FOREIGN PATENTS Germany Oct. 23, 1922 Germany Mar. 29, 1935

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