US1530326A - Centrifugal pump - Google Patents

Description

March 17, 1925. 1,530,326

v H. A. PRINDLE CENTRI FUGAL PUMP Filed-Jan. 4. 1923 4 Sheets-Sheet l March 17, 1925;

H. A. PRINDLE CENTRIFUGAL PUMP Filed Jan. 4. 1923 4 Sheets-Sheet 2 n* 7 Y U n 1- V 0 l d w 1l 1 ,A rf/w au 2 IW a am 1 7 l-l March 17, 1925. 1,530,326

H. A. PRINDLE CENTRIFUGAL PUMP Filed Jan. 4. 192s 4 sums-'sneek WITNESSES l/VVENTR /HTOKS March 17, 1925. 1,530,326

l H. A. PRINDLE CENTRIFUGAL PUMP Filed Jan. 4, 1925 4 Sheets-Shea?l 4 WIT/VESSES INVENTOH /j/Z@ i M2, a" @M MMS A Asible Patented Mar. i7, 1925.

UNITEDv STATES APATEN'I oFF! iipnemon mei January 4, ma.' serial iro. siam.

To all whom it may concern.'

Be it known that I, HARRY citizen of the United States, of East Orange, county of Essex, and State of New Jersey, have invented certain new and useful Im rovements in Centrifugal Pumps, of which the following is a speccation.

Centrifugal pumps of the kind known as sump or bilge pumps are generally placed horizontally in the sump pit and are hung b suitable supports from a sump cover pliite. Such pumps, owing to their inacces- A. PRINDLE, a

osition and also to the fact that they are ogten r uired to handle liquids carrlying more or ess suspended solid materia s, as sand or sewage, must be not only rugged and simple in construction, but reliable in operation. To these Y qualities must be added if possible cheapne of .construction and efficiency of perfomance. And to more nearly attain these' results is the object of the present invention. Sump pumps well known in the art have beenmade of the ordinary volute vtype with the tangential discharge on one side leading up through a discharge pipeV to and through a plate cover. Such pumps have to be well braced to overcome the reactive thrust due to the side dischar e and even vwhen so braced they are su jected to stresses tendin to bend the shaft and this gives rise to vi rations that are detrimental to the eiiiciency and the durability of the pump.

It vcan readily be seen that any bracing that would hold the shaft straight for any given output, would, due to the elasticity of tliebracing, be either too slack, or too tight, for other outputs, so that every impulse or change of load, will be the cause of vibrations, that may be uite objectionable. Besides a separatede ivery pipe, on to one side, renders the pump awkward to handle in restricted pits.

Irihese objections have given rise to a class of sump pumps in which the suspending member is made use or as a discharge pipe; the shaft being jeuriigried in a hub iii the lower end of this pipe; the hub being in from the pump eas- 't turn supported by varies ing. Such pumps may either have an inipellei of the 'enclosed type, or of the semienelosed type; but in either case they are r sii anda residentv supports, into the central pi that forms at once the discharge ipe, t e pump su port and the shaft gui e. water, as it is discharged'from the impeller, strikes violently against the hub-vanes and is compelled to abruptly change its direction of How and also to suddenly change its velocity. This results in eddy and friction losses that seriously impair the efficiency of the pump and cause more or less vibration. Could the volute form of discharge with its gradual change of direction and volume be introduced such losses would not be so marked.

In a pump constructed according to 'my present invention I retain the advantages of the volute form o`f delivery from the impeller to thedischarge and by using a balanced number of such'volutes, so constructed as to first lead off circumferentially, in the direction ofthe line of flow, then to turn inwardly and join the central discharge,-I attain at once a balanced effort that imparts no bending stressto the pump support and yet gives the desired eiciency.

In the accompanying drawings which illustrate an embodiment of my invention in the form of a sump pump,

Fig. 1 is a side elevation of the pump;

Fi 2 is a vertical axial section showinr the ischarge pi e and certain details o? the driving mem ers;

Fig. 3 is a vertical axial section of Pump;

Fig. 4: 1s a plan and partial section of the pump casing;

the

Inthiscasetev.

Fig. 5 is 'a side view and partial section a e erring to Fig. l a sump pit is shown a H1" 3 is shown nd. a pit cover at 2.

plate has i secured. packing box 10 is formed in the upper part of the elbow and through this box the pump shaft 11 extends downward through the center of the pipe 5 and carries on its lower end the impeller 12. The lower end of lthe shaft is journaled in a bearing 13 set in a hub portion 14 ard the pump casing 15. A tube 16 extends from the lower bearing to the packin box above and surrounds the shaft as a s roud to protect the same from any fibrous or strin material from bein wound around it. e bed plate 6 has a so cast integral counter bore in the boss, a lock nut 22, with bearing 23 is centrally located a locking'screw 23 holds the thrust block fixedly in place when once adjusted. A ball in the thrust block and two lock nuts 25 on the shaft support the shaft on the ball bearing and take the thrust due to the suction of the impeller. At 27 I show the usual form of flexible coupling between the motor shaft and the pump shaft to compensate for a slight misalignment of the motor and pump. It. is to be noted that the guide andthrust bearing being su ported 1n one integral piece with the pac 'ng box insures accurate alignment between these two bearings which conduces to smooth running, which would not be so easily attained if the packing box was carried on a se arate member like the top plate or the vertical ipe 5. U

The ump casing whic involves the principal idature of my invention has an 1mpeller chamber .28 closed at the bottom by a bottom or suction plate 39 in which is the central suction orifice 40. A ange 41 on the upper` side of the impeller runs in a pocket formed in the upper part of the lmpeller chamber and the lmpel er has holes 32 for admitting water into the pocketl from the impeller chamber so as to maintain a balance of pressure on the two sides of the impeller. The periphery of the impeller chamber I form into two volutes 29 as shown in Fig. 6 instead of the single volute that has been customary in such centrifugal pumps. The chamber has, therefore, two cut-waters as shown at 30. When the water reaches the cut-water it passes into a volute pipe 31 which continues on circumferentially as shown in Fig. 4, turns inwardly up over the impeller chamber and into the central discharge opening 32 from which' the water ows into the vertical dlscharge. pipe 5. The object of this construction of' discharge passages is to avoid abrupt changes in the direction and velocity of the iiow. It will be noticed that the water as it leaves the periphery of the impeller 1n a tangential direction continues` to move in this tangential direction with constant velocity while gaining in volume during its p assage through the volutes 29 in the perlphery of the impeller chamber, and then entering the volute pipes 31 at this constant velocity and still movingin substantially the same direction it is gradually turned toward the center discharge, while-at the same time gradually increasing in volume with a corresponding reduction in eed and increase in pressure. Upon reachlng the center of discharge it is gradually given an upward turn by the upwardly curved swells shown at 32 with the result that it enters the' discharge pipe 5 in a direction substantially parallel with the axis. There is, therefore. a minimum of dierential velocity imparted to the water as it leaves flows along in volute channels 29 and this minimum of diierential impetus is maintained clear through the volute pi es 31 and into the central discharge pipe. rom thisA it follows that there will be a of eddies with a resultant increase f eciency. The volute discharge assagesV being opposite and vequal will ring vonly torsional stresses on the pump, `thus avoiding any tendency to bend the shaft or to set up deleterious strains and vibrations.

1. A centrifugal pump having a pump ca sing characterized by an impeller chamber with one or more volutes formed in the periphery thereof and one or more volute passages leading from said impeller chamber to a central discharge.

2. A centrifugal ump the casing of which has an im er chamber characterized by a volute periphery and a volute connecting passage leading circumferentially from said chamber and curving upward and inward to join a central discharge.

3. A centrifugal pump of the character described, comprising an impeller, and a pump casingl aving a central discharge opening and a multivolute impeller chamber and a plurality of volute passages leading from the volutes in the impeller chamber to the central discharge opening.

4.-. A centrifugal pump of the character described, comprising an impeller, anda pump casing having a central discharge opening and a multivolute impeller chamber with a lurality of volute passages leading circu erentially from the volutes in the Aimpeller chamber and then turning inwardly to connect with the discharge opening.

5. A centrifugal pump of the character described, comprising an impeller, an i1n peller shaft and a pump casing, said pump casing having a central portion forming a the impeller and bearing for the shaft with al central di'sdescribed, Comprising an impeller, an im- 10 charge opening on one side of the said cenpeller shaft and a pump casing havin a tral ortion and a multivolute impeller central discharge opening and a multivo ute cham er on the other side and a plurality of impeller chamber with a plurality of volute 6 volutepassages leading circumferentially passages leading circumferentially from the from the volutes of the lmpeller chamber in volutes in the impeller chamber and then 15 the direction of the line of flow and then turning inwardly and upwardly into the curving inwardly to the discharge opening. central discharge.

6. A centrifugal pump of the character HARRY A. PRINDLE.

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