US2368962A - Centrifugal pump - Google Patents

Description

Feb. 6,'1945.

original Filed June 1:5, 1941 s 'w Q H T 'a .33

C as

, c. BLOM GENTRIFUGAL PUMP 3 Sheets-Sheet 1 rrpAwfx i Feb. 6, 1945. c. BLOM .CENTRIFUGAL PUMP Original Filed June 13, 1941 3 Sheets-Sheet. 2

CARL 51.0, v INVENTOR Feb. 6, 1945. c. BLOM 2,368,962

CENTRIFUGAL PUMP original Filed .June 1s, 1941 s sheets-sheet s l xi l ji l ma E20/v,

INVENTOR ATTORNEY.

Patentedl Feb. 6., 1945.-

oFF-lcE cENfrRIFUGAL UMP yCarl Blom, San Marino, Calif., assignor to Byron Jackson Co., Vernon, Calif., a corporation ot Delaware Original application June 13, 1941, Serial No.'

397,836. Divided and this application 1943, Serial No. 481,719

I v 2 Claims.

This invention relates generally to centrifugal pumps, and particularly to medium-pressure single case pumps of the ftype usually employed j(cl. 10s- 111) and to the base.'

for pumping Various classes of ,liquids in indus- A principal object of the invention isto simpliA fy the construction of a pump of the foregoing 'type in order to reduce the cost ofv manufacture and to facilitate dismantling: and re-assembly of the pump at the installation point.

A f urther object is to provide a pump of the foregoing type which is particularly adapted to handle liquids at/ high temperature. It is of utmostv importance that adequate provision be made in pumps intended vfor this service to insure vagainst differential expansion between parts -at those critical points where surfaces contact to maintain centering or alignment between separable parts of the pump. Otherwise the centering or aligning surfaces may separate as the result of: Idifferential expansion, and may April 3.

IIn detachably'secured to the bracket The-bracket I1 serves to rotatably support an impeller. shaft I8 extending through the two brackets I1 and I5 and into` the casing I0. A pai'r of impellers I9 and\20 are keyed to the innern end of the shaft, and are pedestal secured thereon by a nut 2I Fthreaded on the result in objectionable vibration of the in-I adeluately supported part. It is an object` of this inventionto prevent such dierential expansion by subjecting al1 mating portions of the pump to corresponding heating or cooling .iniluences.

- `'Ihe manner in which the foregoing and other objects areattained will be apparent from the 'i following detailed description of one embodimentl ofl the invention,reference being had to the accompanying drawings wherein:

Fig. 1 is a longitudinal vertical sectional view of a pump embodying the, invention;

Fig. 2 is a horizontal section taken on line II-II oIFig. 1 andV A Figs. 3, 4 and 5 are transverse sectional views end of the shaft. l l

- Attention is directed particularly to the novel arrangement of viiuid passages in the pump casing III, which greatly simplifies the assembly and dismantling of the pump. It will be observed that the suction eyes of the\impellers I9 and 20 face eachother, thus disposing the corresponding suction passages in the casing in the central portion thereof between the mpellers'. A-suc. tin inlet passage 23 extends from the suction nozzle 24 to the eye 4oi? the rst stage impeller I9 and is separated from the second stage inlet passage 25 by^a partition 26- hav/ing a wear ring 21,forming a throttle bearing with a sleeve 28 keyed to the shaft between the impeller libs.-

As shown most clearly in Figs. 4 and 5, the pump is of the double volute type, each impeller discharging into a pair 4of diametrically opposed 'olute passages' in the pump casing. In this manner the radially acting hydraulic thrusts 7 are balanced, andthe impeller shaft is relieved spectivelyfof Fig. 1.

Rferring t0 the drawings, there is shown-o A and 33 are curved radially inwardly and merge two-stage'centriiugal pump having a pump casing-III.. l The Iliis preferably an integral casting ha ,gllaterally extending' bolting -prov'i Loti??? 811121101121118 min'l .ltfwm be Oh seryedgtiiat the opposite endsA ofthe-f .casing are ded-,with identical annular b'oltingilan'ges nu menti-cover." 1s the opposite danse I l, to ccm- '(@Wdtheimwllfmmthe brsget otheru 'srtcinngbox bracket ls '-issecu'red of the bending 'stress which would otherwise be imposed thereon if' a single volute wereprovided. Referringv particularly, to Illig.` 4, fdia' metrically opposed volute passages 30 and 3| are formedin the pump casing in the radial plane of therst-stage impeller I9. These .passages are connected to then second-stage inlet 25 by individual cross-over passages 32 and 33 (Fig. 2) extending from the respective volute passages 3|! and 3l in.a.;generally axial direction on oppositesides of the suction inlet passage 23; After passing the inlet passage23, the cross-overs 32 lwidth ma. radial direction, anc the provision' of individual crossovers extending vfrom lthe respective volute passages and around opposite sides of the large inlet Vfpassage ail'ordsv a. very compact and symmetrical construction.

' Thearrangement o t the discharge volutes' for 'the second stage impeller 2| is shown in 1F18. '5. I-'he volutes 35 and 30 start at diametricaliropposite points on the circumference of the impeuer openingin" the casing, the volute 25 extending the impellerv and being eprated from the vo1ute as by-(a parution 31, which terminates near the upper endof the discharge nozzle 38. v

Referring vonce more to Figs. 1 and 2, theshaft opening through the stumngbox bracket I5 is sealed by a packing gland 4| of usuall construction, 'but the' stuflingbox extends inwardly of the pump casing to a point adjacent the impeller I9. in order to shorten the over-all length of the pump. In order to prevent undue heating of the packing when the pump is used-to pump hot liquids, /the silmngbox is surrounded by a cooling jacket 42 `to permit circulation of water or other' cooling medium between an inlet (not shown) and an outlet 43. As is customary, provision is also made for circulation of water through the stuiingbox from an inlet connection d to a lantern'ring ,45 and thence between the packing 4| vand a shaft sleeve |16 'to an outlet 41 inithe packing 'follower. i p

It Twill be noted that the pump casing ill is provided with a cylindrical centering surface Sti adjacent the bolting'ange I3, and that the stuffingbox bracket I5 is provided with agcorresponding centering surface 5I adapted to have a close sliding llt in the centering surface 5|! to insure axial alignment of the bracket with the pump casing. It is essential that thesesurfaces 5 0 and 5I be of substantial length, asshown, and be maintained in contact with each other in or Y* der to avoid vibration of the bracket. It hasi been found, however, 'that thesesurfaces .fre-v maybe heated to a higher temperaturethan the stuingbox bracket, inasmuch as the latter is subjected to the cooling iiuence of the cooling water in the jacket 42. This is particularly true in pumps ofthe type illustrate in Figs. 1 and 2 wherein the centering flange El is relatively long and the stungbox is extended 'inwardly into the centering ange, as close to the impeller as possible, in order to shorten the over-all length of the-pump.

In order to avoid separation of the centering surfaces 50-and 5|, I have provided an arrangement whereby the portion of the stumngbox bracket I5 throughout substantially the entire length of the centering surface 5I is subjected to the heating inuence of the pump liquidato thereby cause itto expand or contract with the pump casing. To this endg the inner radially extending/wall of the bracket I5 is recessed into the water jacket 42 throughout substantially thel entire length ofthe centering surface 5I, asindicated at 55, to provide an annular pocket or channel 5B which contains pump liquid Jwhen the pump is in operation. The annular ange A51 this formed'between, the pocket 5B-andvthef centering surface 5I is'thereby isolated from the 4 cooling eiect ofthe'cooling liquld'inthe jacket 4 2 throughout substantially its lentire length and .is exposed directly to the-'pumpv liquid, and will be heated to approximately thesame temperature as theportion ofthe casing I on which the centering surface '50 is formed. In this manner, diilerential expansion between'the pump casing ,and the bracket in the region of the centering surfaces 50 and 5| is avoided, and vibration of the bracket resulting from separationof the s'ur- .faces 50 an d5| is consequently eliminated.

Referring now to the bearing bracket I1 and it will be observed with reference to Figs. 1 to 3 that the bracket comprises an inner circumferential wall 60 forming with the end covers 6I and 52 a completely closed bearing housing, and

an outer wall 63 spaced' from the wall` 60 to form therewith a cooling 'jacket 64. Cooling liquid is circulated through the jacket between an inlet 65 and an outlet t6. 'A deflector ring 6|a is secured to the shaft 'adjacent the en'd cover 6| ato preventfcooling liquid issuing from the stumngbox from entering the bearing housing. The shaft I8 is journaled in the bracket I1 in spaced bearings 61 and 58, preferably of the ball bearing type. The bearing 61 assumes only radial thrust, being mounted for limitedsliding movement in the bearing seat 69 in the bracket. The bearing 68 assumes not only-radial load but also any axial hydraulic thrust imposed onthe shaft by the impellers. To this end, the outer race of the bearing 63 is provided with a circumferential groove containing a split retaining ring 'I0 adaptedtobelamped between the end wall Y of the bracket and the end cover 62. The inner The bore 1I inthe bracket is only slightly largen `than the inner bearing 61, to permit the latter to be inserted freely therethrough during assembly. I I I have provided a novel and improved system of lubrication of the bearings 61 and 68. The

housing formed by the walls B, 6I and 62 constitutes a lubricant reservoir having a lling open-l ing 15 through the upper wall'and adrain port 15 in the sump formed in the lower portion. A "A0 supply of lubricant is maintained at approxi- ',lnately the level indicated at 11. An oil'fiinging disk 18 is secured to the shaft approximately midway between the bearings, as by a set screw 19, and it will be noted that the anges of the .45 disk extend below the level of the lubricant.

During rotation-ofV the shaft, the lubricant ad- 'hering to the submerged portion of the disk iianges is carried upwardly and flung outward- 1yv by centrifugal force against the wail of the housing.

In order to collect the lubricant flung from the disk and to direct it to each bearing, a channel 80 (Fig. 3) is formed on the inner wall of the housing.- As shown most clearly in' Fig. l, the

.55 channel slopes downwardly in opposite directions from the centralradial plane of the disk 18. Ports. 8| andf82 extend through the end walls of theV br lof the channel 80, to direct the lubricant from the channel to chambers 83 and 84 between the outer sides vof the bearings and the end covers .5I and 62. From these chambers the lubricant iiows through',` the bearings and lreturns to the reservoir. A continuous circulation of oil through l o5 bearings is thus provided. on `the radially opposite side of the housing and approximatelyv at the same elevation as the ports Bland 82, a

pair of overflow ports 85 and/86 extend through the end walls of tlie housng to allow any excess lubricant to by-pass the bearings anddthus control the level of the lubricant in the chambers '53 and 8l. l

The oil-flinging-disk 18`is superior inseveral A respects to the conventional oil rings -now in com- 76 mon use. A ring looselggmounted ori the shaft et in registry with the respective ends that the disk 78 is slightly smaller than the bore il in the outer end wall of the housing, to permit insertion of the ring when mounted on the shaft.

From the foregoing description, it will be apparent that I have'provided a pump which is exceedingly simple to assemble and dismantle, and

which will provide trouble-free operation over a long period of time irrespective of the temperature of the liquid being pumped. The manner of assembly is believed t0 be obvious. It is desired-t6 call attention, however, to the ease of dismantling to permit inspection of the rotating parts and the interior of thepump casing. Up.. on removal of the end cover I6, the impeller nut 2i is removed from the shaft, permitting the removal of the second stage impeller 20. After the stuingbox bracket I5 has been unbolted from the ange I3 on the pump casing and the detachable pedestal IIa has been removed, the entire unit comprising the stufilngbox bracket I5, bearing bracket Il, and the shaft I8 with the impeller I9 thereon may be withdrawn bodily to the right, thus affording access t'o the interior of the pump casing and permitting inspection of the impellers. as the suction and discharge connections form a part of the pump casing, it is not necessary to disturb those connections in order to dismantle the pump.

If it is desired to inspect the bearings 61 andv 68, this may be accomplished with only slightl additional dismantling. The impeller I9 is removed from `the left end of the shaft, the end cover 62 is unbolted from the bearing bracket I'I, and the defiector ring 6IL is loosened, and there-l after the shaft I8, bearings 6'!A and 68, and oilflinger ring 18 may be withdrawn to the right as a unit, leaving the brackets I5 and Il, packing gland 4I, and shaft sleeve 41 intact. Separation of the bearing bracket from the stuiiingbox bracket is, of course, necessary in order to renew the packing 4I. It will be apparent from the foregoing that the pump is susceptible of being separated into various sub-assemblies to permit not necessary, however, to completely dismantle the pump in order to inspect and/or renew a.

single part.

It will be appreciatedthat certain aspects .of

It willbe noted that inasmuch panying drawings, but is of the full scope of the appended claims.

This application is a division of my co-pending application Serial No. 397,836, filed June 13, 1941, for Centrifugal pump.

I claim:

1. In a rotary pump particularly for pumping hot liquids, the combination of a pump casing having a cavity therein and an opening in a wall thereof; a closure member fitting said opening and having a central shaft opening therethrough, said closure member and casing having opposed centering surfaces of substantial length and exe tending inwardly of the pump casing to a point adjacent a pump impeller, said centering surfaces` normally contacting each other to maintain said closure member in. a predetermined position; a rotor shaft extending through the shaft opening 'in said closure member; 'packing means sealing the joint between said shaft Aand said closure member, said packing means extending inwardly of said, closure member substantially the length of said centering surfaces; said closure member having a passage therethrough for circulating a cooling medium in heat exchange relationship with said packing means rto cool the latter; and the inner wall of said closure member being recessed adjacent said centering surfaces' a distance substantially equal to the length of said centering surfaces to dene a chamber containing pump liquid, thereby to provide substantially equal thermal expansion of the portions of .inspection of the various operating parts, but it is i construction and bearing lubrication system may also be used in conjunction with other types of pumps than that described. It will therefore be understood that the invention is not limited to the detailed construction shown inthe accomsaid casing and said closure member in the region of said centering surfaces.

2. In a centrifugal pump particularly for hot liquids, the combination of: a casing having; a cavity therein and an opening through a Wall thereof, a closure member detachably secured to the casing andtting said opening, said closure member having a shaft opening extending therethrough; said casing and closure member having opposed surfaces cooperating to center said closure member, said surfaces being relatively long and extending inwardly to a point adjacent a pump impeller; a rotor shaft extending through the shaft opening in said closure member; sealing Vmeans between said shaft and closure member extending inwardly to a point beyond the opening in said casing and adjacent said impeller; said closure member having a fluid passage A,therein for circulating a cooling medium in cooling relationship to said sealing means, said fluid passage .extending in relatively close proximity to lsaid opposed centering 'surfaces and tending to influence 'of the cooling medium, comprising re- V.

entrant walls on said closure member between said centering surfaces and said cooling medium passage and deiinin'g a chamber containing pump liquid extending outwardly substantiallythe length of said centering surfaces,`wherby the portions of said casing and saidclosure member in the region of said centering surfaces are main- .tained at approximately the same temperature.

CARL `BLOEM.

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