US2601828A - Centrifugal pump - Google Patents

Description

July 1, 1952 v. s. LOBANOFF 2,601,328

CENTRIFUGAL PUMP Filed Feb. 4, 1949 2 snmars -smzsm 1 IN VEN TOR.

Va/ 5 lobanof/ BY 3/ I W4 A 7 TOQNE Y V. S. LOBANOFF CENTRIFUGAL. PUMP July 1, 1952 2 SHEETSSHEET 2 Filed Feb. 4, 1949 INVENTOR. Val 5. Lobe/7019 ATTO/QA/a Patented July 1, 1952 CENTRIFUGAL PUMP Val S. Lobanoflz', Berkeley, Calif., assignor to United Iron Works, a corporation of California Application February 4, 1949, Serial No. 74,500

2 Claims. (Cl. 103-109) This invention relates to an improved multistage centrifugal pump. The invention relates more particularly to a pump having a plurality of stages, each including a double volute discharge so that the radial pressure is balanced in each stage; the pump is also preferably arranged vertically with the first stage at the bottom so that an adequate net positive static head is maintained at all times on the pump; the several stages are arranged on the shaft to provide little if any axial thrust on the shaft; finally, the entire pump unit is so mounted in its outer casing that the pump discharge pressure is utilized to maintain theum't fluid tight in a simple and convenient manner. a

It is in general an object of the invention to provide a novel pump having the foregoing characteristics and advantages.

The invention includes other objects and other features of advantage, some of which, together with the foregoing, will appear hereinafter wherein the present preferred pump construction is set forth. In the drawings accompanying and forming a part hereof, Figure 1 shows in vertical section a pump embodying the present invention, the upper half of the view being taken along the line AA of Figure 2 and the lower half of the view being taken along the line Bl3 of Figure 2.

Figures 2, 3 and 4 respectively are sections taken along the lines 22, 3-3 and 4-4 of Figure 1.

Referring to the drawing, the pump shown comprises a head structure generally indicated by numeral 6, an outer casing structure 1 and a pump unit 8 provided in a spaced relation within the outer casing 1. These units will be discussed in the order mentioned.

Head structure 6 includes an inlet conduit H and an outlet conduit l2. Outer casing I is generally cylindrical in section and is flanged at its upper end as at 2| for attachment by studs 22 and nuts 23 to the head structure 6, a gasket 24 being interposed between the two. A support ring 21 is welded to the casing l at a convenient elevation. The lower end of the casing is closed by plate 28, secured in place as by welding 29; plate 28 includes an aperture 30 therein closed by a suitable end closure 3 I.

The pump unit 8 comprises a plurality of different stages and that shown includes eight stages although more or less can be employed as desired; each stage is made up in a conventional manner, that is, it includes a centrifugal impeller 4| fitting within a cooperating casing 42 and adapted to receive fluid on one side and discharge it forcefully toward the outer periphery of the impeller and into double volute discharge passages 43 and 44 in the casing 42 so that the radial pressure in each stage is equalized. Each impeller 4| is secured to shaft I! by a key 45, a spacer 32 being provided between each impeller; shaft sleeves l6 and 53 are secured at each shaft end to protect the shaft against abrasion by any solid in the fluid handled by the pump.

In accordance with this invention, the several volute casings 42 are so arranged that inlet passage H from the head structure 6 is continued by passage 41; further, the lowermost volute casing 42 is fitted with an end closure 48, including a passage 49 therein to direct feed into the first stage of the pump which is the lowermost stage within casing l; the discharge passages in the first stage are connected by a conduit 5| to a cavity 52 provided beneath guard sleeve 53 in closure 48 and bushing 54 at the lowermost end of shaft I! to force fluid from the first stage between the guard sleeve and the bushing and so keep these cool and free running. A similar arrangement is provided at the other shaft end wherein guard sleeve [6 runs in a bushing 31 mounted in the head structure 6 adjacent to the uppermost pump stage. The bushing terminates in passage 13 which is connected to inlet passage II; the gland or stuffing box l4 provided about the guard sleeve also terminates in passage I3 so that it is only subject to the inlet fluid pressure.

The several stages are provided in such relation to one another along shaft I! that the shaft H is substantially free of axial thrust. This is accomplished by dividing the pump unit into two opposed stage groups; in the first group, the first stage indicated at El discharges into the next uppermost stage 62, which in turn discharges into the next uppermost stage 63 and thence into the next uppermost stage 64, which is about midway along shaft II; this stage then discharges through passage 66 to the second group which includes the uppermost stage 61, this stage then discharging to the next lower stage 68, which in turn discharges to the next lower stage 69, which stage discharges through outlet ll about midway of the unit into the space provided between the pump unit 8 and the casing l; the discharge pressure passes upwardly between the pump unit and the casing and thence out through passage I2. Thus, the thrust of the two groups is balanced, one against the other.

Each of the volute casings 42, except that in the uppermost stage, includes two circumferential 3 recesses 40; a like recess is provided in end closure 48. A ring 33 is fixed into each adjacent recess pair to hold the several units in alignment; each 'of the casings is formed with parallel fiat ends so that they fit together snugly in a stack in which they are retained by rings 33. The uppermost casing is provided with a circular shoulder 34 fitting into a like recess 35 in thehead structure 6 to align the unit and the head. The several stages and the end closure are also aligned by three rods 16 which are extended through the head structure 6, the several volute casings and the end closure 48 to retain these together. The rods merely serve to prevent rotation of the several casings making upthe'unit andtheir displacement, the actual pressure holding the components fluid tight being applicati'onof the discharge pressure into the space between the unit and the casing. With this construction, only the outer casing is subject to bursting pressure,

'the'pressureappliedjtothe several casings d2 only From the foregoingI' believe it will be apparent that I ha've provided a'novel and simple pump constructionin which the'pressure availablefrom operation of the pump is utilized to hold the inner volute casings in a fluid pocket without any gaskets. It "is very simple'in construction, can be assembled and dismounted readily, being rugge'd in construction and combining "a high effieien'cy' in operation. Further, thepump'embodies both radial and axialbalance without the use of any high pressure balancing drums, discs, floatinjg seals or other complicatedbalancing'devices.

I Claim; '1. A centrifugalpump comprising a cylindrical outer "casing open at the upper end thereof and sealed at the lower end thereof; aclosure-for "the upper casinge'nd secured thereto "and including an inlet conduit, an outlet conduitfrom said casing; and a'pum'p unit, mounted in said casing and "depending from said closure in a spaced relation to said casing, said'unit including a pump shaft mounted in said outer casingand having'a plurality of impellers mounted thereon 'intwo opposed groups'to provide a substantial absence of any axial thrust on said shaft, a double volute casing mounted cooperatively with respec to each impeller, the unit including a conduit from said inlet conduit to the'lowermost stage in saidpu'rnp to supply fluid thereto, said unit including a final pump stage intermediate of the unit iand di'sc l' arging into the space between said unit and said outer casing to apply the pressure of fluid discharged from said unit to the exterior of said unit to maintain said unit fluid tight; each double volute casing having a flat face on each side thereof, said faces being normal to the axis of rotation of said pump shaft, and a peripheral recess, a ring fitting in the recess in each two adjacent double volute casings, a rod extended through the several double volute casings to retain them against displacement; a bushing in the end closureabo'ut the pump shaft and having an end terminating short of the end of the shaft, a stufling box about the pump shaft and having an end terminating in a spaced relation to sai'd bushing, and a conduit about the bushing endand the'stufiing box end and leading to the inlet conduit.

'2. --A"-'centrifug'al pump comprising a cylindrical outer casing open at the upper end thereof and sealed at the lower end thereof; a closure for the upper casing end secured thereto and including an inlet conduit, an outlet conduit from said casing and a'pump unit, mounted in said casing and depending from said closure i'na;-s'pace d relation to said casing, said unit includin'g'apump shaft mounted'in said outer -ca sing-and-having a plurality of impellers mounted th'ereo'n ih two opposed groups to provide a-substantial absence of any-axial thrust on said shaft-a double volute casing mounted cooperativelywithrespect toe'ach impeller, the "-unit including a "conduit leading from said inlet conduit totheqowermoststa'ge' in said pump tofsu'pply fluid-thereto,"saidunitincluding a final i m stage'inte'rinediate 'o'flr tjhe u'nit'and discharging into"the*sp'ace between said unit and aid outer casing to apply the'p're'ssur'e of fluid discharged from said unit to the exterior of said unit to maintain 'said *u'nit "fluidtight; d first bushing in the end c osure e o'ut' 'the piimp shaft and having an end terminating "'sl rort of t e end or the shaft, a sta n box a out the pump shaft and having an end terminatingin' 'a spaced relation to said -firs t bushing, and a' condui-t about the-bushing endand'thej'stufiin'gbox 'end and'leading to the inlet-conduit,a,' g 11 bushinglabout the en orsaid'shaftadjacent'said lowermost stage, said second bushing having-"an end terminating into a ea vit 'wh eh commentcates'withan outletof-apumpfstage locatedf above the'inlet'to said "lowermost stage, saidfirstand 'said second bushings 'beirig lubr'icated by 'fiuid

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