US2873685A - Centrifugal pump - Google Patents

Description

Feb. 17, 1959 E. UMBRlcHT 2,873,685

CENTRIFUGAL PUMP Filed Oct. 18, 1954 2 Sheets-Sheet 1 26,4 1 INVENToR.

EMlL UMBRICHT ATTORNEYS Feb. 17, 1959 E. UMBRlcl-IT 2,873,685

CENTRIFUGAL PUMP Filed Oct. 18, 1954 2 Sheets-Sheet 2 INVENTOR. EMIL UMBRICHT ATTORNEYS United States Fatent CENTRIFUGAL PUMP Emil'umbnchf. Jackson, Mich., 'assigns to Ajem Laboratories, Inc., Detroit, Mich'.

Application October 18, 1954, Serial No. 462,661-

10 Claims. (Cl. 10B-105.)

This invention relates to centrifugal pumps and more particularly to multiple stage pumps ycapable of delivering a high volume of liquid at high pressure. The invention isdescribed as embodied in a two-stage nonclogging pump having separate high and low pressure outlets.

In many industrial applications it is desirable to supply liquid at two or more diierent pressures. .In some of these applications 'the pumps .which supply this liquid must be of non-clogging design. For example, in `the high-pressure washing of metal parts, the soil and other debris removed from the parts is recirculated inthe sysfem and the pumps must be self-cleaning= in order to operate 'eiciently over long periods of time. The pump -provided by the present invention is .non-clogging and also is arranged to deliver the liquid through twosepara'te outlets at two different pressures. Thus, in applicationsrequiring twoY sources of liquid at diierent pressur'esf, a' single pump can vbe used to supply both lrequirements. A,

"The various aspects, features, and objects of this in.- vention will be apparent from the following description of a twosstage pump embodying the present invention considered in Vconjunction with the accompanying drawings in which: I i

, Figure V1 is an elevational view of the two-stage pump; Figure 2 is an enlarged vertical, sectional view ofthe lower portion of the pump assembly; t

Figure 3 is a sectional View takenalong line 3--3 of Figure 1;

Figure 4 is a transversesectional view through Figure `2 showing the arrangement of the lvanes on the lower impeller plate;

Figure 5 is a sectional view showing the shape ofthe scroll housing of the low-pressure pump section;

Figure 6 isa sectional view taken along line 6 -6 of FigureV 2` and shows the arrangement of the stationary f' .t @ce by means of the co'm'm'on drive shaft 6 which extends downwardly within the supporting column'lS. y

'In operation, the liquid to bepumped enters the lower 'end of `the' pump assembly 22as indicated b'y the broken arrows 26, A portion of the water entering the inlet 26 is discharged Vat*relatively low pressure through a lowpre'ssure loutlet '28 and a perdon of 'this wateriis transferred tothe second or higher pressure stage 24 of the pump and is discharged at substantially higher vpressure through alhigh-'pressu're outle't'32 as shownl in Figure 1. A The low-pressure stage of the pump includes an impelle'r having a circular impell'er plate 34 (Figure 2) which carries si-xl taperedfvanes "36 (see also Figure 4) secured to 'the lower surface of the plate 34 and which are curved as shown. for example with a radius of curva- 'ture 'equaltothe radius of the impell'er plate The plate -34 is secured` to a reduced end-portion 38 of the shaft`6 by means of a hub 42 that is keyed or otherwise secured to the shaft 38. f I

This impeller is mounted withinV a housing which includes a generally spiral Scroll 44 around the impeller vanes and an annular plate 46which slopes down- 'wardly toward, the central axis ofthe pump and is spaced immediatelybeneath the vanesf3'6. The outer ends of the vanes 36 open into a scroll chamber 48 which is of ex-l pandinglcross-sectional area in the direction of liquid iow as best illustrated in Figure 5.

The liquidwhich is thrown outward by the centrifugal force'generated by the vanes 36 travels'around vthe spiral scroll,areaifSkv and apo't'ion of this liquid is discharged through thelow-pressure outlet 28. AY portion of this liguid, howevergtravels upwardly around the outer edge .ofr-.theimpelle'rplate'34 into an annular cavity 52 which directs the liquid back ytoward thecentral vertical axis of the pump. Y

The liquidwhich enters the cavity 52 has a rotary motion as well as an upward motion in the'direction of the movement of the vanes 36V. This circular movement of the water is retained as itis guided toward the center of 'the pump by 'means of six stationary vanes 54 be'st shown in Figure 6. These vanes are secured tothe underside of an annularidividi-ng plate 56 which separates the low pressure and high pressure stages of the pump. These stationary vanes 54 are curvedas shown in Figure 6 so that water passing through the cavity 52 retains its rotary motion as it is fed into the central area adjacent vanes in the chamber connectingthe lowand high pres- IFigure 8 is a sectionalwiew"showing thelshape of the l high pressure scrollV housing. s i

The pump is supported as shown in Figure l byla housing2 which is .generally square inrcrosssection and has one open side provided withl mounting anges 4 as sho'wn in the sectional'view ofFigure 3.

The pumpis driven by a drive shaft 6 (Figure A2) which extends vertically through vthe housing. 2 and is rotatably supported by upperI and lower bearings 8 and 12 (Figure 1), mounted respectively on the upper and lower rend plates 14 and 16 of the housing'Z.` Thepurnp`- ing mechanism proper is mounted beneath` thehousing 2 and is supported by the lower end plate 16 through' a tubular support 18 whichcarries a! lowpre'ssure 'pump assembly, generally indicated at 22, and a high-pressure pump assembly, generally indicated at 24, botl'i yoperated impeller plate is secured to the lower endprtion138 of the shaftv 6 by means of a hub 64 `which extends downwardly from the plate 62 and is keyed or otherwise s'ecured to the. shaft portion 38. The hubs 42 and .64 may bey heldin position on the shaft 6 by means of a nut 66 in threadedfengagement with a reduced end-portion 68 on-the, lower end of the shaft 46. v

The liquid thrown outwardly by the vanes 58 lis received in a high-pressure yscroll cavity 72 -of`expanding' cross section in thedirection of liquid 'movement around the Iouter ends of the van'es 58, andfwhich -opens into the high-pressure outlet 32. The shape of this scroll cavity is' best shown' in Figure 8.

Immediately above the impeller plate 62 the diameter fof then-rive shaft 6 is increased and passes through the' central openingV in an annular supporting 'plate 7*'4 that i'sisecured to the lower end 'of the supportin'gff'coluinn v18. There-are no shaft bearings beneath the bearing'lZ s'that the entire lower portion of the assembly can be immersed in the liquid to be pumped to the liquid-level line indicated at 76 in Figure l.

Because the liquid in the high-pressure scroll cavity 72 is under pressure, a portion of this liquid passes upwardly around the outer edge of the impeller plate 62, along the upper surface of this plate and thence upwardly through the clearance opening 78 between the shaft 6 and the annular supporting plate 74 into the supporting column 18. This flow of liquid is important in preventing the accumulation of sediment or other debris on the upper surface of the impeller plate 62 which would interfere with the eicient operation of the pump. Howf ever, because of the high pressure of the liquid, an excessive ow of liquid along this path is undesirable because it would reduce the overall eiciency of the pump. Accordingly, six, small, radially-positioned auxiliary vanes 82 (see also Figure 7) are secured to the upper surface of the impeller plate 62 and oppose this flow of liquid. However, the dimensions of these auxiliary vanes 82 desirably are such as to permit a limited continuous controlled flow of liquid into the supporting column 18. This liquid is returned t-o the tank by means of openings 84 (see Figure 1) in the supporting column 18. With this arrangement all of the bearings may be positioned above the liquid level s-o that the presence of detergents or other chemicals in the liquid being pumped will not affect the operation of the bearings.

*'In -the illustrated embodiment of the pump, the entire assembly is constructed from sheet steel thus permitting rapid low-cost fabrication of the pump. It will be apparent, of course, that various portions of the mechanism may be formed of castings or parts fabricated by other means. In the sheet steel construction illustrated in the drawing, the entire housing of both the lowpressure and high-pressure stages is supported by the column 18 which is welded to the annular supporting plate 74. A coupling ring 86 is welded to the outer edge of the plate 74 and supports the upper housing plate 38 which extends around the high-pressure scroll cavity 72. An annular steel band 92 is welded to and extends downwardly from the outer edge of the scroll plate 88 and the llower edge of this band is welded to the outer edge of the dividing plate 56.

The dividing plate 56 in turn supports the lower pressure housing by means of an annular ring 94, the upper edge of which is weldedV to the lower edge of the dividing plate 56. The space between'this ring 94 and the outer edge of the impeller plate 34 permits the entrance of liquid from the low-pressure stage into the connecting chamber 52.

The tapered low-pressure vanes 36 provide a chewing or digesting action for any debris, such as a piece of cloth or other material which might be introduced accidentally into the pump, between the lower edges of the vanes 36 and the sloping annular plate 46. This chewing action results from the curved configuration of the vanes 36 as shown in Figure 7. Thus, the effective clearance between the lower edgesof the vanes 36 and the upper sur- -face of the plate 46 is not constant between the inner and outer edges of the vanes, thus tearing or chewing up of any materials which might tend to clog the pump while at the same time permitting the vanes 36 to be formed from pieces of sheet material having rectilinear sides and making it unnecessary to cast the vanes 36 in tegrally with the low-pressure impeller plate 34.

The pump illustrated in the drawing is well suited for industrial use and in operation has a capacity of between three and five hundred gallons per minute for each stage of the pump, with the low-pressure stage delivering liquid under a fifty toseventy foot head, while the high-pressure stage delivers the remainder of the liquid with a head between yl50 andv 200 feet. It will be apparent that the pump can b e modified in various ways `to best suit the needs of each particular use and that various details of construction may be s-o modified without departing from 4 the scope of the present invention as set forth in the following claims. n

This application is a continuation in part of my earlier application Serial No. 357,450, filed May 26, 1953.

What is claimed is:

1. A multiple stage pump comprising a housing having first and second scroll sections and a casing joining said scroll sections and defining an annular transfer chamber positioned between said first and second scroll sections and connecting said scroll sections, said annular transfer chamber communicating with said first scroll section along the full length of said first scroll section, first and second impellers positioned respectively within said first and second scroll sections, a drive shaft extending into said scroll sections and supporting said first and second impellers, said first impeller including an impeller plate secured to said drive shaft and rotatable therewith and a plurality of impeller vanes secured to the lower surface of said impeller plate, said impeller plate being positioned near the upper portion of said first scroll section and separating said first scroll section from said annular transfer chamber, the upper `surface of said impeller plate engaging the medium being pumped in said annular transfer chamber, and means spaced from said housing rotatably supporting said drive shaft, said housing having inlet means and low pressure outlet means communicating with said first scroll section and high pressure outlet means communicating with Said `second scroll section.

2. A pump as claimed in claim l wherein said shaft is supported wholly by bearings positioned a substantial distance above said housing.

3. A pump as claimed in claim l wherein said transfer chamber connects the outer portion of said first scroll section with the inner portion of said second scroll section.

4. A pump as claimed in claim 3 including a plurality of curved stationary vanes positioned Within said transfer chamber, and directed inwardly and inclined in the direction of motion of the upper surface of said rst impeller plate, whereby the ow of the medium being pumped is directed inwardly over said upper surface.

5. A pump as claimed in claim l wherein said housing is supported by a column connected to the top thereof and extendingupwardly therefrom, said column having a plurality of liquid outlet openings therein, and said second impeller includes a vsecond impeller plate, impeller vanes on the lower surface thereof, and auxiliary impeller vanes on the upper surface thereof and having surface area sufficient to limit the flow of liquid from the second scroll section of said housing to said column and insuflicient to prevent such flow.

- 6. A pump as claimed in claim 1 wherein each'of the vanes of said first impeller is tapered along at least a portion of its lower edge andY the surface of the vane is curved, said housing having a sloping annular member positioned adjacent the tapered portion of said vanes and surrounding said inlet means.

7. A multiple stage pump comprising a housing, a first rotatable plate positioned within Said housing, a first set of pumping vanes supported by and extending outwardly from the front face of said plate, a second rotatable plate positioned within said housing and spaced from thereverse side of said first plate, a second set of pumping vanes supported by and extending from the front face of said second lplate toward the reverse side of said first vplate but spaced therefrom, an annular dividing plate closely adjacent the front extremities of said second set of pumping vanes, said dividing plate having an opening communicating with the inner ends of the second set of vanes, a casing dening an annular chamber between said annular dividing plate and the reverse side of said first rotatable`plate,said Yannular chamber communicating with the outer ends of said first set of vanes through an uninterrupted `annular passage surrounding the entire periphery of said first rotatable plate and a rotatable shaft secured to saidrfirst and second'rotatable plates, said housing having inlet means communicating with the inner por tions of said rst set of vanes, low-pressure outlet means communicating with the outer portions of said first set of vanes, and high-pressure outlet means communicating with the outer portions of said second set of vanes.

8. multiple stage pump as claimed in claim 7 and wherein stationary vanes are secured to said annular dividing plate and extend into said annular chamber to positions closely adjacent the reverse side of said first impeller plate.

9. A multiple-stage pump as claimed in claim 8 and wherein the outer diameter of the casing defining said annular chamber is substantially equal to the diameter of the second rotatable plate.

10. A multiple-stage centrifugal pump comprising a drive shaft, first and second spaced rotatable impeller plates secured to said shaft, said first rotatable plate being secured to the end of said shaft with its front face away from said second plate,.a first plurality of impeller vanes secured to the front face of said first plate, a second plurality of impeller vanes secured to the front face of said second rotatable plate, a housing surrounding said shaft and said first and second rotatable plates, said housing defining rst and second scroll-shaped centrifugal discharge channels adjacent to the perimeters of said first and second rotatable plates, respectively, an annular partition secured to said housing and projecting inwardly adjacent to said second impeller vanes, said annular partition being positioned approximately mid-way between said rst and second plates with the inner edge of said partition defining an inner annular opening communicating with the inner ends of `said second impeller vanes, the space within said housing between said annular partition and the reverse of said first plate defining an annular transfer chamber communicating with said inner annular opening and communicating with said first scroll section through an outer annular opening extending completely around said first plate, whereby the circular motion of the uid passing from said first scroll section through said outer annular opening is unimpeded and the circular motion of the uid passing from said transfer chamber through said inner annular opening is unimpeded.

References Cited in the file of this patent UNITED STATES PATENTS 933,247 Goeriz Sept. 7, 1909 1,273,913 Ostenberg July 30, 1918 1,637,652 Ness Aug. 2, 1927 1,752,366 Brown Apr. 1, 1930 1,892,930 Burman Jan. 3, 1933 2,245,114 Orleans .lune 10, 1941 2,419,669 Birmann Apr. 29, 1947 2,504,140 Mill Apr. 18, 1950 2,701,530 Schellerer Feb. 8, 1955 FOREIGN PATENTS 212,879 Great Britain 1925 474,433 Canada June 14, 1951 509,463 Germany Apr. 10, 1929

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