US1849127A - Centrifugal pump - Google Patents

Description

March 15, 1932. A B, woon 1,849,127

C ENTRIFUGAL PUMP Filed Nov. 19. 1925 )W25 f n Y Patented Mar. 1:5, 1932 Y NITED .STATES maar' n. woon, orNEw oBLEANs, LOUISIANA cENTnIrUeAI. PUMP Application and november 19, 192s. 'serial m. 149,303.

This invention relates to improvements in centrifugal pumps and particularly to those employed for pumping more or less viscous materials or fluids such as sewage sludge, paper stock, and the like. A pumpemployed for this purpose and known as a trash pump is shown in my U. S. Patent No. 1,182,439, patented May'9th, 1916.

Difficulties have been experienced in such pumps in that viscous fluids s'uch asmentioned above do not freely enter the body of the impeller, that is, tothe bladesproper, due to the speed at which the forward ends or entrance edges of the blades move and to the relative sluggishness of the liuid. In consequence of 'the above the impeller churns the iuid'with` the result that the pump does not deliver at full capacity and therefore the eiiicienc thereof is reduced.

One of the primary lobjects'of this inventionis to provide a simpleand effective pump adapted to overcome the above diflculties.

A more specific object of the invention is to provide in a pump of the character described an improved impeller whereby the uid beingl pum d is acted on in such a way as to increase t e efliciency and capacity of thepump.

'Other vobjects and advantages will appear hereinafter in the specification ofthe preferred form of my invention illustrated in the accompanying drawings, whereinz' Fig. 1 is a cross section of a. pump constructed in accordance with my invention;

Fig.l 2 is a sectional view of the impeller` line 2-2 of ig. 1;and" 4 Fig. 3 is a diagrammatic section taken 'on the line 3-3 0f Fig. 2, illustrating the contour of a `ridge 1 employ connecting the blades of the impeller.

Referring now to the comprises ingeneral a casing A an lmpeller or runner B, and an impeller driving shaft C having a bearing in the upper part 'of the casing A. v The pump is of the centrifugal type and is rovided with a central inlet 4 and a circumerential discharge'or volute f5, the fluid be- 50 ing drawn in thru the inlet 4 by the impeller drawings the pump of my pum the section being taken onthel that anything whzh` passes the'inlet and then timpelled and vdelivered tothe circumferential discharge or volute5.

The impeller B comprises two spaced walls or discs 6 and connected in this instance by a pair of impeller blades or vanes A8, 8 dis- 55 posed onopposite sides of the. axial centre of the impeller. The plate 7 is provided with a central'opening 9 thru which the fluid to be pumped enters the impeller, and the plate 6 has aridge or rib 10 formed thereon,'which 60 ridge connects the blades 8, 8.

.'lhe blades 8,' Shave theirinner ends 11 rounded on a considerable radius and extend to the peripheries of the discs where they occupy but little space. They are given 65 a curvature suitable for the purpose of mpelling the flu-id together with foreign substances therein contained through the pump, and of transmitting thereto force appliedto the pump, thereby increasing 'the velocity ofy 70 the Huid.

vReferring more particularly to Fig. 1 it will be seen -that the plate or disc 6 is of true disc form atits periphery but that it increases in thickness inwardly,.its inner face 75, or surface curving toward lthe centre of the impeller where it terminates in the ridge 10 above mentioned.

The ridge. 10 in this instance is shown roundedgggon a considerable radius and is 80 joined to the blades by iillets of considerable radius whereby no sharp `angles or corners are presented tothe fluids ybeing pumped and thusthe likelihood of trash'becoming caught orlodgedis minimized. This togethertyvith 85. the'gpeculiar shape of the bladesl '8, 8 insures will rbe passed by the impeller. ,"5 v It is further pointed out that the ridge or rib,l0 is so formed as lto cross the axial centre 9p lof the impeller and that this ridge is of least f depth at the centre, f'om whence it gradual-5 l ly increases depth tol smoothly merge with. 1 l the blades. "As will be seen in Fig. 2 the ridge increases in width from the 'centre to the 95 point of joining the blades atzwhich point rib very much resembles an S although in this particular section the Sis reversed, and thus the impeller may be said to have-a substantially S-shaped blade the central por- 5 tion of which is of'less height than the res maining portions thereof.

The theory of the action of a pump constructed in accordance with my invention is as follows:

The sluggish, fluid in advance of the pump moves relatively slowly. The blades move relatively rapidly and tend to produce relatively high velocity of the iiuid. This change in velocity of the iiuid cannot be eiiiciently brought about in the absence of an intermediary instrumentality because of the character yof the iiuid. The ridge acts ,as this intermediary. By virtue of the factthat the ridge is in the central portion of the impeller its motion zis relatively slow and it operates somewhat as a dividin wedge or Water shed imparting rotation an some degree of velocityto the entering iuid, which in turn facilitates the entrance ofthe iuid into the body of the impeller where thevanes proper impart to itthe velocity. and so called centrifugal effect necessary for its discharge into the volute against the pressure or head opposing such discharge. The transition from 80 relatively low to relatively high velocity is thus graduall and efficiently brought about. From the oregoing it will be seen that through my improvement the capacity and efficiency of centrifugal pumps of the character described may be greatly increased, as

the objectionablechurning of the iiuid heretofore present vin such pumps is overcome.

I cla1m: l. Ina centrifugal pump having a central l inlet and a circumferential outlet the combination of an impeller, vanes on opposite sides of the axial centre of the impeller, land a ridge connecting said vanes, said ridge being vso shaped that it merges smoothly with the blades and increases in4 height from `the axial center of the impeller to the b1ades. .I 1 2. In a centrifugal pump having'a central inlet and a circumferential outlet the .combination of an impeller,"vanes on opposite sides of the axialpcentre'of the impeller, and a' rounded ridge connecting said vanes, said ridge being joined to the vanes by fillets of a considerable radius.

3. In a centrifu alpump having a central inlet and a circum erential discharge the combination of an im eller comprising spaced discs-and a pair o impellerblades connecting said discs, one of said discs having a central opening through which the matter `to B0 be impelled enters the impeller, and the other disc having a ridge formed thereon connecting the blades, said ridge crossing the axial centre of said disc and increasing in height from the axial center of the disc to the blades. 4.' `Inxrcentrifugalpum'p having a central inlet and a circumferential discharge the conibination of an impeller comprising spaced discs and a pair of impeller blades connecting said discs, one of said discs having a central opening through which the matter to be impelled enters the impeller, and the other disc having a ridge formed thereon connecting the blades, said ridge crossing the axial centre of said disc, and being of increasing Width and height from the centre to the point of joining the blades.

5. In a centrifugal pump having a central inlet vand a circumferential discharge the combination of an impeller comprising spaced discs and apair of impeller blades connecting 80 said discs, one of said discs'having a central opening through which the ,matter to be impelled enters the impeller, and the other disc having an inner surface curving from a true plate at its periphery toward the centre of the impeller and there terminating in a rib connecting the blades of the impeller.

-6. In a centrifugal pump, an impeller having an inlet eye, a vane, and means having a surface sloping and decreasing in height from y said vane to the axis of the impeller adapted to impart rotation to the matter to be moved.

7 In a centrifugal pump, an impeller having aninlet eye, ia. vane having a rounded entering edge, and means having a rounded cross-section and having a surface sloping and decreasing in height fronrsaid vane to the axis of the impeller adaptedlto impart rotation to the matter to be moved.

' 8. In a centrifugal pump, an impeller hav;l T00 ing an inlet eye, a pair of vanes at the side I .of said eye, and a rounded ridge sloping and decreasing in height from said vanes to the axis of the impeller.

. 9. *In a centrifugal pump, an iin.pellerhav 105 ing an inlet eye, vanesat the side of said eye; thel said eye being unobstructed between said vanes except for a rounded ridgev sloping and decreasing in height from the said vanes to the axis ofthe impeller. 110

10. A centrifugal pump impeller having vanes provided with convexly curved forward ends and projections at said. forward ends 4which incline toward the axis of rotation of the impeller and which are of greatest cross sectional area at portions of the vanes farthestremoved from the inlet of the pump.

11. A centrifugal pump impeller vane hav- -ing a rounded forward end and a projection on said forward' end tapering toward the in- 120 let of the pump and extending toward the axis of rotation of the impeller.

' 12. -A centrifugal pump impeller including a vane supporting Wall, and vanes extending from said'wall toward the inlet end 125 of the pump, each of said vanes having a convexly curved forward end provided with a projection extending from said forward end toward the axis of rotation of the impeller, said projection being of,..greates't cross sec- 1 0 v and tapering toward t signed my name.

' ALBERT B. WOOD.

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