US2791183A - Impeller for centrifugal pumps - Google Patents

Description

y 7, 1957 N. 1 T. YGGE 2,791,183

IMPELLER FOR CENTRIFUGAL PUMPS Filed Dec. 14, 1953 2 Sheets-Sheet 1 y Inventor:

M'ZsErzZ' T'or'sten yy e,

United States. Patent' O ice The present invention relates to centrifugalpump rimpellersaand-is'more ,particularlyconcerned withqa new .and improved doubleasuction impeller for centrifugal pumps ."forahandling thick or. viscous :fluids-cor fluids containing :foreignmatter in suspension. The present application is .a continuation. in part of my pending application, Serial No. 335,183,..filed February. 5,. 1953, :now

abandoned.

Clogless impellers .for centrifugal".gpumps designed to handle thick or viscous fluids orfiuids containinglforeign matter .in suspension, sewage pumps .for example, :are well known. fact that .the danger of the pump becoming clogged will henreduced to a minimum.

In. using ,such impellers, theremay be -drawbacks -due tonneven balance because the outletofthe iimpellertis They rarecalled clogless owingrto .the

.notactive on .more. than .halfsofits periphery: andsalso. f

because, lin=single suction; impellers, atgreat'axial .thrust may arise since the impeller inlet iisnon ly Ifrom one-side.

It is an ob ject ofxthe present invention vto -provide a new and improved centrifugal pump impeller completely overcoming.theiabovementioned drawbacks and vyielding improved operation.

Another object of the invention isto prov ide anew :and improved centrifugal ,pump impeller in whichwthe lfiuid channels or'passagesare of optimum .shapeto promote siiuidlflowand topermit passage oftsolids.

A further object of the invention is torprovidea-new randuimprovedimpeller of'iheftvpe described which may 'be readily cast, 'is economical of .metal andlrugged construction.

A Stllliffllithl'! object ofitheinventionzrisitosprovide a new and improved centrifugal-pumpimpeller in which the channels will be readily accessible for cleaning ,pur-

'poses.

'Stillanother object of the invention is to provide a new and improved impeller'oftheftype described which maybe either of the open -orclosed a arietv.

.. The invention is 'featuredlby Zth'e ,provisiontdflascen- 'tri fu'gal pump impeller of the double-suction type in which the fluid passages or channels extend from both sides thereof to the circumference with an even number of vanes forming the channels. The channels are arranged in crossing pairs, with their outlets arranged in succession so that the whole periphery of the impeller is effective. The vanes are formed in such a way that their planes at the outlets are substantially parallel to the drive shaft and gradually turn over so as to be substantially at right angles to the drive shaft at the impeller hub, this turning of the planes of the vanes alternating in direction with every other vane.

Further objects, features and advantages of the invention will become apparent from the following detailed description and the accompanying drawings illustrating presently preferred embodiments thereof in which like numerals refer to like parts in the several views and in which:

'Fig- 1 is va side elevation of an open'zdoubleendedaim- .pelleriem bodying, the invention;

Fig. 2 is aright-liand elevational view of thesame with portions of the :housing .in -broken lines;

Fig. 3 .isa vertical cross sectional view taken onJ-line 3-3 of.F.ig. 1;.

Figs. 4 through .6 are developed sectionalviews take on the arcsd .throug'h 6. of.Fig. 1;

Fig. 7 .is .a developed circumferential view taroundta .portion o'f theperimeter ofthe impeller onarc 7.-.7 :of Fig. 1.; Y

Fig. 8 is a fronttelevationalview'of.-a-.modified iorm of impellertaccording. to the invention .havin-gside. walls with portions of one sidewall brokenaway; i

.Fig. 9 is rari'ghtehand .e'levationalviewof the same portions of the impeller housingindicatedrby broken lines; t a

Fig. 10 Lisa generally vertical wsectional viewtakenon IOQHLQfFig. f8;,

Figs; .-1 1a .and'lll through. 13 are. developed sectional views taken eon arcslla and..1'113 Fig-.8; .and-

Fig. 14 is=a developed circumferential .view aroundea portion of the. perimetertof the impeller taken alongar .14'14 of Fig. '8.

Turning to the embodiment of Figs. .1- .7., .anropen type doublesnctiom clogless impeller, according: to the invention, is indicatedgenerally'by thennmeral 16.- The impeller '16 has an aXialoperfinglT ,to receivea drive shaft '18,.hownin broken lines, to which it isfkeyed or otherwise suitably aifixed to be driven thereby. Thelmpeller may be. mounted to revolve in a suitable ihous'in'g '20,,-,a'lso shown in broken lines. The fluid to be ,pumped by. the impeller is .fedfthereto .near its hub .21 through iriletsZZ and 24 formed 'in opposite sidesv .of thercasing 20. The casing has an outlet 26, also shown 'in broken lines, opposite. the tips 28a and 28b of therirnpeller. vanes 30a and 301),, all as bestseen .inldig. 2.

In Figs. 1-7 an impeller havings'ix.vanes is illustrated. For convenience, referring 'to Fig. 2', .thosevanes whose inlet is on the right have been indicated by the numeral 30a and those whose inlet 'is on the left by the numeral 30b and other portions thereof in asim'ilar manner. Each of the evenmuniber vanes 3.0a .andl30b is-Jiormed with a driving surface 32a an'cl3'2lzfland a .trailingsurface 34a and 34b. Each driving or pumping sur'face 32a and 32b recurves gently as at 36a and 3.61) to fornra curving or fluid diverterportion surface without sharp angles to prevent clogging. As shownlby the developed sectional'views, Figs. 4-6, andthe developed circumferential view, Fig. 7,,,in every case the planes y y of'the vanes at the periphery of the impeller are substantially jparallelto the axis of the drive rshaftandpgradually turn .over so.as 'tofbe substantially at rightangl'es to the aiiis 'of the s'h'aft' near the hub oftlre impeller. 'Tliis turning. of the planes of the vanes is done alternately With every other vane in the opposite direction and perhaps is best seen in Figs. 4-7 wherein the plane of one of the vanes is denoted by the lines yy and a plane through the axis x-x is indicated by the line u--a. The gently curving channels, formed by the vanes and adjacent walls of the casing, lead from the inlets on both sides of the impeller and pass to the periphery. With this arrangement it is evident that the impeller is eifective over substantially its entire periphery and pulsing is thereby avoided.

With the construction illustrated, the vanes may be made as thin as in an ordinary centrifugal impeller. There is no wasting of metal as by heaping and no parts of the impeller are ineffective as in other clogless impellers.

In the form of the invention illustrated in Figs. 1-7, the impeller is of the open type. Thus the sides which cooperate with the vanes to form the outlet and fluid passages are integral with the casing and the danger of the pump becoming clogged by foreignlmatter carried in the fluid will be reduced to a minimum. Furthermore,

due to the special shape of the vanes,,losses at the inlet of thistype of impeller are reduced, the fluid flowing without shocks and more directly than in those pumps wherein the edges of the vanes interfere with fluid flow.

Additionally, this type of impeller is suitable for centrifugal pump castings having bearings on, both sides. It 'i can be used efliciently in sewage pumps with a vertical shaft and totally submerged in sewage. Furthermore, the vane channels on one side of the impeller may be made wider than those on the other side and other dimensions novel features of the invention is disclosed. The impeller, indicated generally by the numeral 40, is closed at both sides by walls as seen in Fig. 9, the side wall on the left being indicated by the numeral 42 and that on the right by the numeral 44. The vanes, which form webs between the walls, turn alternately in opposite directions, those whoseinlets are on the right being indicated by the numeral 46a and those whose inlet is on the left'by the numeral 46b. The driving surfaces of the vanes 46a are indicated by the numeral 48a and that of the vanes 46b by the numeral 48b.

As illustrated in the developed views of Figs. Ila-14,

the planes y-y of the vanes at the periphery of the impeller are parallel to the drive shaft 18 and gradually turn so as to be more and more at a right angle to the shaft as the hub is approached and to be substantially at a rightangle at the hub.. The side walls 42 and 44 and the vanes 46a'and 46b cooperate to form enclosed channels or passages 50 which turn alternately in opposite directions and connect the inlets 52a and 52b to the outlet 26.

It will be seen that in an enclosed centrifugal pump of the ordinary double-inlet type, the novel impeller according to the invention atfords numerous advantages. From the developed views of Figs. Ila-14, itwill be observed that the channels in the new impeller have greater hydraulic radius than those of an impeller of-the ordinary type, the hydraulic radius being the relation between the area of a channel and its periphery. The hydraulic radius is greatest for a circular section and smallest for a parallelogram extended in length or a rectangle. In impellers of the ordinary type, each of the channels at the inlet is divided in half by a wall necessary to bind the impeller together. The channels of the ordinary impeller, therefore, are of a less advantageous shape for free flow of the fluids than are those of the novel impeller of the invention. For example, in an ordinary impeller having six vanes there must be twelve channels in the inlet,

whereas in the novel impeller as illustrated in Figs. 8-14,

only six cha'nnels'in the inlet are required. The resistance to fluid flow in a channelbeing in inverse proportion to the hydraulic radius is therefore less in the novel impeller according to the invention.

Furthermore, as already indicated, the novel, construction of the new and improved impeller permits greater ease and economy in manufacture. Casting will be simpler and easier to perform. The cores for the vane channels in the mold will also be stronger at smaller dimensions of the impeller. Furthermore, the channels in 'the complete casting will be more accessible for cleaning.

While I have herein disclosed and described presently preferred embodiments of the invention, it will be understood that such disclosure is by way of illustration and not by way of limitation and that various modifications and changes may be made in the same, the invention being not in any way limited to the specific disclosure but only to the scope of the following claims:

I claim:

1. A centrifugal pump impeller adapted to be mounted for rotation about an axis, for double suction pumping of fluids having solids suspended therein and flowing into said impeller from opposite axial directions, which comprises an even-numbered multiplicity of vanes and a fluid diverter portion extending from said vanes toward said axis, said diverter portion having generally parallel surfaces defining a thin wall to separate said fluids flowing thereagainst from opposite axial directions, said surfaces being substantially planar and perpendicular to said axis toward said axis and being provided with a corresponding even-numbered multiplicity of axially directed undulations varying in depth smoothly from imperceptibility toward said axis to a maximum at said vanes to accelerate most efliciently the rotational velocity of said fluids from said vanes as well as said diverter portion have generally parallel surfaces defining a thin sheet, said diverter portion merging imperceptibly into said vanes.

. 3. An impeller in accordance with claim 1 and including side walls enclosing said vanes.

References Cited in the file of this patent UNITED STATES PATENTS 1,975,214 Hollander Oct. 2, 1934 1,849,127 Wood Mar. 15, 1942 FOREIGN PATENTS 18,343 Great Britain of 1900 218,636 Switzerland Apr. 1, 1942

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