US1037243A - Centrifugal pump. - Google Patents

Description

A. E. GUY.-

GENTBIFUGAL PUMP.

nrmoumx FILED un. 11, 1912.

Patented Sept 3,1912.

2 sums-sum 1.

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.unnm 1:. evil. or memos, new masnr.

To all whom it may concern:

1 Be it known that I, ALBERT E. GrtiY, a

types of pump in which the pump casing ismade in two separable arts, joined on a plane parallel with the axis of the shaft, and also in which the rotating parts are maintained in a fixed position relatively to the stationary parts by means of a thrust bearing or its equivalent, and particularly to improvements in the tightening devices for the prevention of leakage at-the running joints of such pumps. I

The objects of my invention are first,.to minimize leakage; second, to prevent the leakage currents from disturbin the main flow of the fluid enterin the impeller or impellers of the pump; third, to properly direct the flow of the li uid into the impeller or impellers; fourt to reduce friction at the tightening of the joints by avoiding contact between the fixed and the revolving vparts; fifth, to economize material in, prolong the useful life and facilitate replacement of the tightening parts; and sixth, toimprove the etliciency of such pumps.

In the accompanying drawings, Figure 1 represents part of an axial section of a twostage pump, of the multi-stage type, embodying my invention; Fig. 2 IS a diagrammatic view. illustrating the defects which my invention is intended to remedy; and Fig. 3 is a view similar to Fig. l and showing the circulation of the liquid traversing a pump embodying my invention.

In Fig. 1. 1 designates the shaft u)on which the impellers 2 are mounted. The pump casing 3 is split on a plane through the axis of the shaft 1 and is rovided,

preferably at the discharge end of t e pump,

with a suitable thrust bearing for the shaft. The arrangement of casing and thrust hearing may be varied but, preferably, are shown Specification o! Lotion mm. Application filed lie-rah 11, 1912. Serial No. 882,967.

otherwise well designed pump. the direction and the velocity of the liquid cnurmuou rm.

Patented Sept. 3, 1912.

inlet chamber 12 then an im ller chamber 5, followed by a return'ben 6, delivering intothe return passage 7. In said return passage 7 are ribs or guide vanes 8, the purpose of which is to guide the liquid centripetally into the inlet bend leading to the second impeller. With this type of pump, to each impeller, except that ad acent to the discharge sidethere is an impeller chamber, a return bend, and a return passage provided with guide vanes and the combination of these parts constitutesone stage of the pump. The return bend of the last stage leads the li uid centripetally into a discharge chaidlier 10 provided with one or more flanged openin s'for connection to the discharge main. Hince, although Fig. 1 illustrates the application of my invention to a" two-stage pump, itis understood that said invention may be applied to a pump having any number of stages. Said invention may also be appliedtto single stage pum s, either of the multi-sta 'e type, or of the ouble suction type; in this latter type, the li uid is led simultaneously to both sides 0 the impeller.

There are two points of main importance to be considered in the construction of an I One is that at the point of contact with the first element 11 of the vanes, or vane inlet, are fundamental factors in the calculation and delinealion of the shape of thevanes. Therefore, when anything occurs which deviates the direction and changes the velocity of the liquid at the vane inlet, the performance of the pump will be different from. and in variably not so good as was intended. The other that,.as the liquid leaves the impeller, nothing can add to the energy it possesses. and everything it contacts with. be

it diffuser passage, diffuser vanes, free whitpool, or easy return bend, will cause a reduction of said energy; but the greater loss of energy, howe\"er,.1n an otherwise well dosigncd pump, is caused by leakage at the running joints. To cover these two important points I devised the invention described in my former application Serial No. 489,187,

for which Patent No. 972,366 was granted. I

chamber H, on the rear of the impeller,

sale of the apparatus.

onto the current of fluid entermg the inlet chamber of the impeller thereby causing a commotion of the vein or stream of liquid and disturbing the flow. The leakage issuing from the labyrinthine passage formed between the intermeshing flanges of the two B, impin es normally onto the current of fluid entering the inlet wearing rings. A and chamber of the impeller thereby causing a contraction of the vein or stream of liquid and disturbing the flow. The leakage issuing from the labyrinthine passage formed between the wearing rings 0 and D, at the rear side of the impeller, mingles with the leakage issuing from the annular clearance space formed between the rotating, sleeve G and the fixed sleeve 'F, and the whole mass of such. leakage passes from the balancing through the holes E, drilled through the impeller web, and impinges against thecur rentof fluid, just before said current contacts with the vane inlet. The result. of

such impact is a contraction of the veinor stream of liquid and a disturbance ,of the flow. The current of liquid entering the impeller comes into contact with the extensive curved surface of the im eller hub and web, extendingfrom the suct on end of the hub to the vane inlet; and as this surface is rotating at a high rate of speed, the mass of liquid directly in contact with said surface is entrained, and in turn, communicates gradually its motion to 'the various surrounding layers'of liquid, thereby deviating the direction of the current of liquid. The net results of the three disturbing elements just described is that the liquid arrives at the vane inlet with velocity and'di-rection differentfrom those upon which the design of the impeller was established; consequently it is not possible to guarantee the exact performance of the pump until after said pump is thoroughly tested out in the laboratory; and uncertain prediction of the performance of a pump always proves a serious impediment in negotiating the The, -intermesh-, ing flanges of the companionwearing rings A and B, andof the companion, rings C and D, were provided with ample axial clearance, and with but justsufiicient peripheral clearance to insure free ruiming of the rotating parts, the eiliciency or tightness of the whole joint depending precisely on the closeness of said peripheral clearance. I have observed, however, that because of the threaded assemblage of the rings B and C on the axially extended flanges of the im eller, it is-not possible for said rings to revo ve concentrically true. It. was'thenfound necessary to allow-greater cripheral clearance between the intermeshin'g flanges so as to prevent actual rubbing and cutting of the neighboring surfaces,-

which rubbing and cutting takes place when'the rings runiuntrue, because. oftheir inherently defective mounting, and also, when the whole impeller runs out of true,

, due to sagging ofthe shaft, or toimperfect balance of the rotating mass. It is obvious that the efiiciency of a labyrinthine joint is greatly impaired when the clearance is large, and also that the resulting increase in leakflowis followed by increased erosion a e 0% the labyrinthine surfaces. It was also found that when the clearance had become: excessive, since no adjustments could bemade, complete sets of companion wearing rings had to bereplaced, which proved to be an expensive proceeding, particularly so in mmmg districts where the'liquid handled is acidulous and carries much grit, therefore necessitating frequent renewals of said 1 rings. My present invention is therefore,

intended to remedy the defects above enumerated.

It is a matter of common observation that when water flows from a straight pipe into a curvedibend or elbow, the deviation of the stream generates centrifugal forces in the water, since intensities vary nearly as the'" radii of curvature of the stream lines.

Therefore,- the pressure'in the cross section of the stream at any point in the elbow will not be uniform; it will vary throughout the cross section, having its greatest value where the radius of curvature is. greatest,-

on the concave side of the elbow, and its least value at or near the convex side. The cross section contracts gradually from the beginning of the elbow, and becomes smallest at the "end of the elbow. Strictly speaking,-when the water flows rapidl' through the bend, it is not in contact wit the convex part of'said bend. Now, in Fig. 1, the passage 9 connecting the main intake chamber et, to the vane inlet 11 is in effect but an elbow; and the passage 13 connectin channel 7 to the vane inlet of the secon impeller is also but an elbow. Consequently,

against the concave side of these elbows. The free surface of the stream (that having the smallest radius of curvature) affects the form of the convex side of an elbow, and

comes smoothly into contact with the suitably located curved flange22, of the impeller'2, just before the stream reaches the the stream, when entering sairl' elbow .passages is deviatedand the centrifugal forces 'thus developed cause the liquid to bear vein inlet 11. Although the parts 9 and 18 affect, in their axial cross section the sha of the concave wall of the pi e bend, they are in fact conoidal shells. he conoidal guide shell 9 surrounds part of the hub of the first impeller, and also the shaft 1 and its protecting sleeve 21; it is provided with an annular part 18 having a flange 17, between which and wall 20 a circular groove is formed. Said circular groove is fitted to flange 19, and flange 17 thus forms the end wall of the shaft ackin space 16. In this manner, said shell 9 is old firml in position, does not come into contact wit the rotating parts, and, when roperly adjusted, forms a smooth and eifbctlve guide for the liquid from the intake chamber 4 to a point very close to vane inlet 11. Said shell 9 is therefore the wall of the inlet chamber 12, for the impeller nearest to the intake orsuction chamber 4. Conoidal guide shell 13 surrounds the hub of the second impeller, and is rovided with a circular flange 15 which ts into a corresponding groove cut intopartition wall 23, and

the adjacent guide vanes 8. In this manner find said shell 13 is fixed, does not come in contact with rotating garts, and forms a smooth and effective gui e for the liquid, from the return passage 7 to vane inlet 11 of the second impeller 2. Said shell 13, is therefore the wall of an interstage inlet chamber 14. The liquid under pressure tends to.

flow from impe ler chamber 5 into the inlet chamber 12, but it is intercepted by a tightening .device forming a running 'oint between the casing wall 28 and thei et flange of the impeller. Said tightening device is composed of the annular flanges 24, 25, 26 and 27. Flan es 24 and 25 are separately mounted on t e external wall of the impeller inlet flange 22: and each of the flanges 261and 27 is inserted into a circular groove cut into the casing wall 28, which surrounds completely the w ole tightening device.

Between the external wall of flan '24 and 25 and the bore of wall 28, and a be- 1 tween the inner wall of flange 27 and the bottom surface. of the groove formed between flanges24 and '25, am la play is rovided so t at radially neigh ring sur aces cannot normally come into contact when, for instance, flanges 24 and 25, which rotate with the impeller, should be set conceutrfv cally out of true, or when the whole rojhting mass should run out of true because of the saggm of the shaft or of the imperfect rotating alance of said mass. A slight lateralclearance, just sumcient to avoid rubbmg contact and to sllowfree running of the rotating-parts, is provided-on esch sideof flan 2;4, snd between the neighboring faces 0 flsnges 25 and=27.; The maintenance of said clearance is insured through themedium ofsthrust bearing rigidly connected thrust bearing receiving one end of forming a running joint between the tition wall 28 and the web of the impe er.

to the exterior of the pump casing, splild e shaft 1 in any of the usual ways, and holding it against axial displacement. The tightenin of the joint is thus secured through t e restriction of the lateral passages left free between adjoining faces of the stationary and rotating flanges. The liquid issuing ast the t-ightenin f{omt follows the free lateral surface 0 ange 24, and thence follows the rounded edge of the impeller flange 22, where said liquid m nles, without appreciable disturbance, with t he main flow of the fluid on its way to the main inlet 11. The erosion produced by the flow of liquid through the joint affects only the neighboring faces of the flanges. Hence,

when upon inspection of the interior parts of the pum it is found that erosion has increased t e' clearances beyond the permissible limit,'it will sufliceto renew the flanges 24 and 27, while each of the flanges 25 and 26 may be simply turned around, the uneroded faces of these latter now serving as walls for the restricted passages. Upon ing necessary another renewal of the flanges, all the flanges may then be removed and replaced by complete new sets. Had the'sct of stationary flanges been made 1n one piece, one new set would have been required at each renewal; the same remark applies to the rotating flanges. Whereas, it is seen that with separate flan es the whole tightenin device lasts one an one-half as lon as w en solid sets of flanges are used. Besides, the material wasted in the renewals is insignificant as compared with that required for solid rings; and the shape and size of the easilybe made, by the user of the pump, the work requiring no special tools jigs or gages.

On the rear of each impeller a balancing chamber 81, and the pressure .therein is substantially equal'to that obtaining in the preceding'mlet chamber, because communication between these two chambers is provided through a number of holes 80, drilled through impeller web 29. The li uid under ressure tends to flow from impe ler cham- Eer 5 also into balancing 'chamber 81, bu t it is intercepted by a tightening device similar to that on the inlet side of t e impeller and Flanges 26 may be located in a separate groove, but I prefer to insert it con ointly with flan 15'mto the same groove in partitiou w 28.

--Mounted on shaft 1, and tightly pressed between the hubs of .two ad oming mpeIlers, is a multi-fl 1 ring 88, surroun ing which another multiring 84', made in halves stationary with,'but removably attached to shell 18, refersbly. a'sjshown, threaded into a recess 5 inside saidshell 18, The com-' flanges are such that they canv ber 14, a tightening device which. qierates unpeller being formed on either side with an extension and 'rotatin bination 0 said ring: 38 and 34 forms be-- tween balancing chamber 31 and inlet chamin precisely the same manner as those provided between the'impeller and the pump casing, that is, the htening of the ioint is secured through restriction oi the lateral passages left free between ad'oining faces 0 the stationary and rotating nges Ample clearance is provided radiu ly so as tordpnrevent contact in (that diregtlilozi under 0 a operating con itions. e ealrage of liqu ili st the shaft tightening device 3334, an the tightening device on the rear of the impellertends to maintain in balanc' chamber 31,11 pressure greater than that o tai-ning in the preceding inlet chamher, but the liquid escapes through the holes 30 and thence, followin .a narrow passage formed between the en -32 of the conoi-dal ide shell and the impeller web 29. said iquid is ided in a direction substantially tangentia with that of, and into, the liquid; current passing from the inlet chamber. proper into the vane inlet 11. In this manner the incoming 1i uid reaches the vane inlet with very littie 'sturbance.

What I claim is:

1. A centrifugal pump comp sing in combination a casing formed w an intake chamber and an impeller chamber, a shaft rotatable in saidcasing. and carrying an impeller located in said impeller chamber, said impeller being'formed on eitlmside; with an annular extension, .aplurality of separately renewable annular flanges removably mounted on each extension and rotating with said eller, and a plurality of seyiaratel renews le annular fia es re mova 1 an non-rotatabl mounted iii the bore 0 each wall of the nnpellen-chamber, Bul-(l' rotutlng flanges, adgoiniag lateral faces of said stationary an of said rotating flanges forming walls of restricted llllg for intercepting egrem-o! liquid im ieller chamber. I

centrifugal pump comprising in combmation a calm formed with an intake chamber and an impeller chamber, a daft rotatable in said casing and carryi an impeller located in said impeller chain mid annular extension and plurality of radially extending, separately renewable, aced annular flanges removably moun 'on'each with-said impeller,- and a plurality of'ra ially arranged, separately renewable spaced annular an removable but non-rotatably mounted a the bore of each wall of the'impeller chamber and arranged to coliperatc with. said lmller flanges, ad oining radially extending aces of and stationary and of'seid rotating flanges forming walls of restricted passages menses for 'utercepta'ng egress of liquid from the impeller chamber.

8. ,A centrifugal pump comprising in combination a. casing formed with an intake chamber and an im ller chamber, a shaft rotatable in said casing and carryingwan 1mpeller located-in said impeller cham r, and

a stations but .removable conoidal guide shell exten 'ng from said intake chamber to a point close to the web of said impeller and serving as a wall of a duct or inlet chamber, leading the incomin liquid smoothly and protectin said liqui from contact with the surface 0 the rotating parts until said llq' uid reaches the vane inlet.

4. A centrifugal pump comprising in combination a casing form with an intake chamber and an impeller chamber, a shaft rotatable in said casin and can ing an im ller located-in sai impeller c her, an a stationarg but removable conoiclal ide shell exben to a oint close to the web of said imller serv' as a wall of a doctor inchamber, liaising the incoming liquid smoothly and protecting said liquidfrom contact with e surface of the rotating arts until said liquid reaches the vane inet,'said eonoidal guide shell being formed with a groove at one end, and an annular flange on the casing fittinfi into the groove of said 'conoidal guide she 5. A centrifuge pump comprising in combination a casm formed with an intake chamber and an impeller chamber, adaft rotatable in said casin and carrying an im ller located in sai impeller chamber, as casing being formed with a balancing chamber on the rear side of said impeller, and astationary conoidal ide shell re movably attached at one en 01 the wall of ;said intake chamber and extending from said intakechamber to a 'nt close to the web of said impeller, an serving as the wall of a duct or inlet chamber leading the incoming liquid smoothly an protecting said liquidjrom contact with the Air-lace of the rotating parts until said liquid reaches the vane inloglsaid conoidal guide shell forming with.- 0 web '0! said impeller, the walla 0! a passage for guidin the liquid issulngtrom thebalancin cham r,through web holes in said impe er,'in a direction mbs'tantially tangential with that of and into the liquid current reaching the vane inlet 0'! said'im er.

6. A anti-i u 1 pump comprising in combination a casing formed with an intake chamber and at least two iggeller chambers and 'a return passage conn 'ng one of said impeller chambers with the inlet chamber of the following impeller chamber, a shaft rotatable in aa1d.casing and carryin an impeller in .each of said impeller c ambers,

ing from said intake chalmbination a casing formed with an intake chamber and at least two impeller chambers and a return passage connecting one of said impeller chambers with the inlet chamber of the following impeller chamber, a shaft 1'0- tatable in said casing and carrying an impeller in each of said impeller chambers, and a stationary but removable conoidal guide shell forming the wall of said inlet chamber and extending from said passage to a point 'close'to the web of the following impeller, said conoidal guide shell leading the incoming liquid smoothly and protecting said liquid from contact with the surface of the rotating parts until said liquid reaches the vane inlet, a partition wall separating one ofsaid impeller chambers and its return passage and formed with an annular groove, one end of. said conoidal guide shell being formed to fit said groove.

8. A centrifugal pump comprising in combination a casing formed with an intake chamber and at least two impeller chambers and a return passage connecting one of said impeller chambers with the inlet chamber of the following impeller chamber, a shaft rotatable in said casing and carrying an impeller in each of said impeller chambers, and a stationary but removable conoidal guide shell forming the wall of said inlet chamber and extending from said passage o-a point close to the web of the following impeller, said conoidal guide shell leading the incoming li uid smoothly and protecting said liquid 0m contact with the surfaces of the rotating parts until said liquid reaches the vane inlet, said casing being formed with a balancing chamber on the rear side of said following impeller, a stationary but removable conoidal ide shell formin the wall of said inlet 0 amber and exten ing from said return passage to a point close to the web of said following impeller, a partition wall separating one of said impeller chambers and its return passage, one end of said second named conoidal guide'shellbeing removably connected to said artition wall and the other end forming with the web of the following impeller the walls of a passage for guiding the liquid issuing from said balancing chamber, through web holes of said following impeller, in a direction substantially tangential with that of and into the liquid-current reaching the vane inlet of said followin impeller.

9. A centri ugal pump comprising in combination a casing formed with an intake chamber and with at least two impeller chambers and a return passage connecting one of said impeller chambers with the inlet chamber of the following impeller chamber, a stationary but removable conoidal guide shell forming the wall of said inlet chamber and extending from said return passage to a point close to the web of said following impeller, a shaft rotatable in said casing and carrying an impeller in each impeller chamber, said casing being formed with a balancing chamber on the rear side of each of said impellers, a multi-fiange ring mounted on and rotating'with said shaft and secured between the hubs of adjoining impellers, and a stationary multi-liange ring removably mounted on the interior of said conoidal guide shell, adjoining laterally extending faces of said stationary and of said rotating multi-flan e rings forming walls of restricted passage or the purpose of intercepting the egress of liquid under pressure from the inlet chamber of said following chamber into the balancing chamber of the preceding impeller.

In testimony whereof, I have hereunto set o my hand.

ALBERT E. GUY. Witnesses:

F. W. WINTER, ELBERT L. HYDE.

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