US2571802A - Centrifugal pump - Google Patents

Description

Oct. 16, 1951 E. R. WILFLEY ETAL I 2,571,802

CENTRIFUGAL PUMP INVENTORS Elmer R. Wfley BY John L. Aldred Jr.

ATTORNEY Oct. 16, 1951 CENTRIFUGAL PUMP 3 Sheets-Sheet 2 Filed April 9. 1948 Y ATTORNEY 01.16,1951 E RwlLFLEY En; 2,571,802

CENTRIFUGAL PUMP Filed April 9. 1948 s sheets-sheet s' ff m-f 9@ Fig. 6.

7 INVENTORS w Elmer R. Wilfley l. BYJohn l. Aldred Jn C ATTORNEY Patented Oct. 16, 1951A CENTRIFUGAL PUMP Elmer R. Wimey` and John L. Andrea, Jr., Denver, Colo., assignor to A. R. Wilfey & Sons, Inc., Denver, Colo., a corporation of Coloradov Application April 9, 1948, Serial No. 19,915

(Cl. S-111) 13 Claims.

This invention relates to centrifugal pumps and' more particularly to the type having a non-frictional or. hydraulically effective seal between the impeller shaft and the pump housing, instead of a frictional seal or stuffing box.

Pumps of the hydraulically sealed or stuffingbox-free type are required where the character of the liquid which the pump is to handle makes the use of stuffing boxes undesirable, such liquids being, for example, corrosive liquids or liquids carrying grit or sand or other mud constituents.

This invention relates to improvements in a type of pump exemplified in the patent to Wilfley No. 1,756,323 in which the impeller shaft unitary with its impeller is shiftable axially with respect to the pump housing so as to open or close an annular gap between the shaft and the surrounding adjacent part of the housing. Automatically or centrifugally operated co-ntrol means shift the shaft against spring pressure so that the gap is opened when the pump is started to remain open while the pump is running, leakage through the gap being prevented by certain hydraulic pressure compensating conditions being established by the running of the pump itself. When the pump is stopped the impeller shaft automatically shifts due to the spring pressure to close the gap.

That pump comprises a frame or base'upon which the horizontal impeller shaft is journalled in a pair of bearings, namely a front and a rear bearing, the impeller or pump itself being disposed at one free end of the shaft. Thus the impeller is fixed upon one free end of the shaft and is surrounded by the pump housing which is fixed with respect to and mounted uponthe base and which has an axially extending suction inlet at its outer end. The impeller-carrying front end portion of the impeller shaftfproper is carried directly by the front bearing which is disposed adjacent to the housing, while the rear end portion of the shaft is axially slidable in a sleeve which in turn is rotatable but not axially slidable in the rear bearing. A centrifugal governor device herein also termed more briefly a centrifugal device or a governor device or simply a governor which in one embodiment is located between the two bearings rotates with the shaft and when rotated responds by shifting the impeller shaft proper relative to the sleeve as between gapopening and gap-closing positions.

Heretofore a key and groove or spline connection provided in such a pump has made possible the axial v shifting of the shaft relative to the sleeve and it also effected the transmission of the drive torque from the sleeve to the shaft. Separate spring means were effective to urge the axial shifting of the impeller shaft in opposition to axial force set up by the centrifugal device. The extent of axial shift between gap-opening and gap-closing position of the shaft is on the order ditions effecting its axial shifting. Otherwise expressed, it is among the objects to eliminate interfaces having sliding contact with one another while being subjected to pressure incident to the transmission of a torque. In other words, it is one of the objects to eliminate a key and groove connection as a torque-eliminating device.

These objects are attained by interconnecting the driving sleeve and the driven shaft through resiliently deformable torque-transmitting elements serving the dual purpose of transmitting the torque and of providing the required spring power coacting with the centrifugal device as the shaft is shifted between gap-opening and gapclosing positions.

More specifically, this invention is embodied in an assembly having alug, arm, projection or flange upon the inner end of the driving sleeve and offset therefrom or staggered relative thereto another lug upon the adjacent portion of the shaft. A band or nat member of resiliently deflectable material or a flat spring element interconnects the two lugs, each end of the flat spring element being fixed to a respective lug. Hence, this flat spring element extends transversely of the shaft although its ends are offset with respect to one another so as to lie in different planes which planes extend transversely of the shaft. Accordingly this offset between the ends of the flat spring member is greater when the shaft is urged to gap-opening position. 'Ihat is to say, the spring tendency of the flat spring element is to flatten the spring and thus to reduce the amount of offset between its ends, as the natural tendency of the spring element is to urge the irnpeller shaft into gap-closing position. Hence, the differential in offset between the ends of the spring, in other Words the degree of resilient deformation of the spring element is equal to the extent of axial shift of the shaft between gapopening and gap-closing positions, in a practical instance kthat differential being on the order of le.

According to one feature the centrifugal device as well as a pair of symmetrically disposed flat spring torque-transmission elements is mounted upon a sleeve member which in turn is fixed upon the impeller shaft The invention possesses other objects and features of advantage, some of which with the foregoing will be set forth in the following description. In the following description and in the claims, parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit. In the accompanying drawings there has been illustrated the best embodiment of the invention known to me, but such embodiment is to be regarded as typical only of many possible embodiments, and the inventio is not to be limited thereto. v

The novel features considered characteristic of our invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof. will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawings in which Fig. 1 is a longitudinal sectional view of a pump embodying the invention.

Fig. 2 is an enlarged part-sectional detail view of the improved torque transmitting device together with portions of associated parts of the pump unit.

Fig. 3 is an end view of Fig. 2 online 2'-2 with parts broken away.

Fig. 4 is an enlarged detail perspective view of the improved torque-transmission device together with associated parts and in particular with the centrifugal device, said parts of the centrifugal device being shown removed so as to expose parts of the interior.

Figs. 5 and 6 are diagrammatic views illustrating the operation of the device by showing the impeller shaft in gap-closing and gap-opening position respectively as a. result of corresponding conditions of the centrifugal device and of the torque transmitting spring elements.

The invention is shown to be embodied in a well-known stuiling-box free type of pump known as the Wilfley pump. The general structural lay-out of that pump as presented in Fig. 1 comprises a base structure Il, for example a casting which has a hollow body portion Il, a foot portion i2 bolted to the body portion as at I3 and a top portion I4. The top portion I4 in turn comprises a front bearing portion l5 formed with a vertical flange portion I6 facing forwardly, and

a rear bearing portion I1. The top portion I4 of the base structure further constitutes a chamber I3 herein also called the governor chamber extending between the front and rear bearing portions l5 and I1 respectively and lprovided with a top plate or cover Il.

The front bearing portion l5 is provided with a front bearing in the form of a ball bearing 2B having balls 2|, an inner race member 22 and an outer race member 23. This roller bearing is disposed between a front bearing plate 24 having sealing rings 24* and a rear bearing plate 25 having a sealing ring 25", both bearing plates being held together and in place as by bolts 2G. The rear bearing portion I1 is provided with a rear bearing in the form of a ball bearing 21 having balls 28, an inner bearing race 29 and an outer bearing race 30. The ball bearing 21 is held in place and directly confined between a front bearing plate 3l havinga sealing ring 32.

shown).

4 and a rear bearing plate 33 having a sealing ring 34. both bearing plates being held together and in place as by bolts 35.

A driving sleeve 36 formed with a shoulder 31 is rotatable in the rear bearing 21 although secured against axial displacement therein as by the shoulder 31 at one side of bearing 21 and an internally threaded stop collar 38 screwed onto the sleeve member 36 at the other side of the bearing 21. The driving sleeve 36 is formed at its inner or forward end with a radial projection or flange portion 38 and has a front bushing 4l and a rear bushing 4I. In these bushings there is rotatable an impeller shaft 42. These bushings or bearings consist of a known kind of self-lubricating material, for example, specially treated brass or impregnated wood or composition. The impeller shaft is axially shiftable with respect to the driving sleeve 3i, the extent of that shift being defined by a certain narrow range or predetermined limits hereinafter further explained.

The front end portion of the impeller shaft 42 is rotatably supported in the front bearing 20 which in turn is bodily shiftable with the shaft 42 relative to the base structure I0, the bearing 2U being unitary with the shaft by being confined directly between a shoulder 43 formed on shaft 42 and an internally threaded stop collar 44 screwed onto shaft 42. The extent of the potential axial shift of shaft 42 is indicated by the clearance d noted between the bearing 2B and the adjacent bearing plate 25.

The impeller shaft 42 is formed with a threaded front end portion 45 tightly screwed into the hub portion 4G of an impeller 41 having main pumping vanes 48 forwardly disposed and auxiliary vanes 49 rearwardly disposed, the vanes 49 being longer than the vanes 48 by the differential I. The impeller 41 is surrounded by a stationary housing body portion 50 having an axially andV forwardly extending suction inlet Il and being fastened to a rear closure plate 52 which completes the pump housing. the housing as a whole being indicated by the dimension D.

This pump housing is fastened or bolted to a bracket member B (the bolts not being shown). the bracket in turn being fastened or bolted (the bolts not being shown) to the vertical flange portion I6 of the'base structure lll. To the rear face of the housing closure plate 52 is fastened a stationary annular labyrinth, member 53 in which lodges the cylindrical hub portion 54 constituting the inlet for the auxiliary vanes 4S. This labyrinth member 53 also surrounds a rotary seal member 55 which in turn surrounds and is iixedly seated upon the impeller hub and rotates unitary therewith. This rotary seal member 55 has a sealing face 5 which is complementary to a stationary sealing face 51 formed upon a stationary seal ring 58 which is xedly set into a stationary seal ring housing 58 also ilxed or bolted to the housing closure plate 52 'along with the labyrinth member 53 by means of bolts (not The stationary seal ring housing 53 has a downwardly directed drain spout 59* for liquid that might leak from the pump housing past the sealing faces 55 and 51.

A controlled although relatively small amount of axial shifting of the impeller shaft 42' will open or close the sealing faces 5S and 51 with respect to each other, and when open will provide an annular clearance or passage designated as P. That is to say, the passage P is open when the pump is running and. the impeller rotating, but is closed incident to stoppage of the pump. Such a controlled shifting of the pump along with the controlled opening and closing of the passage P is effected by a control device C disposed within the chamber I8 which is in the nature of a centrifugal governor device presently to be described.

The governor device C more clearly shown in Figs. 2, 3 and 4 comprises a sleeve or mounting 68 fixed upon the impeller shaft 42.- The rear end of this sleeve has a pair of symmetrically disposed recesses or cut-outs 6| and 62. Each cut-out is flankedby a pair of ears extending parallel to each other and spaced from each other by the width W of the cut-out, the one pair of ears flanking the cut-out 6| being designated by numerals 63 and 64, and the other pair of ears anking the cut-out 62 being designated by numerals 65 and 66. The ears 64 and 66 join at right angles or are integral with a corresponding pair of ange portions 61 and 68 which extend from the rear end portion of the governor sleeve 60.

A pair of swingable governor weight members 69 and 10 are mounted upon the sleeve 60, the weight member 69 being swingable about a pin 1| mounted in and supported by the ears 63 and 64, the weight member 19 being swingable` upon a pin 12 mounted in and supported by the ears 65 and 66. The weight member 69 (see Fig. 4) comprises a head or weight portion 13 proper of a width Wi and a foot or cam portion 14 of a relatively narrower'width W2, the pivotal point of this weight member being represented by the transverse bore 15 (see Fig. 4).. The other weight member 10 correspondingly comprises a head or weight portion 16 and a foot or cam portion 11. The cam portions of thetwo weight members 69 and 10 being disposed opposite to one another engage through their foot or cam faces the adjoining face F of the flange portion 39 of driving sleeve 36. A pair of at spring elements 18 and 19 each of multiple ply construction connect the flange portion 39 of the driving sleeve with respective flange portions 61 and 68 of the governor sleeve or mounting 60. 'I'hese spring elements while allowing for a limited but suilicient relative axial movement between the driving sleeve 36 and the im.. peller shaft 42 also function as torque-transmitting elements between the driving sleeve 36 and the impeller shaft 42. One end of the spring elements 18 is fastened to the ange 39 of the driving sleeve as by a bolt and nut connection 8D, the other end being fastened to the flange portion 61 of the governor sleeve as by a bolt and nut connection 8|. Similarly the other spring element 19 has one end fastened to flange portion 39 as by a bolt and nut connection 82, and its other end fastened to the ear 88 of the governor sleeve as by bolt and nut connection 83. At 84 in Fig. i` is shown a cotter pin for securing pin 1| in place. The flange portion 39 has recesses R1 and Rz to clear the heads of bolt connections 8| and 83.

The operation as illustrated in diagrammatic Figs. 5 and 6 shows the governor device C at rest in Fig. 5 and subjected to centrifugal forces when the pump is running in Fig. 6. These gures show an impeller shaft 85 (corresponding to impeller shaft 42 of Fig. 1), a rotary seal ring 86 (corresponding to the seal ring 55 in Fig. 1), a complementary stationary seal ring 81 (corresponding to the stationary seal ring 58 in Fig. 1) and here considered to be part of the pump housing, a front bearing 88 and a rear bearing 89 (corresponding to bearings 20 and 21 in Fig.

l), a drive sleeve 90 (corresponding to drivingl sleeve 36 in Fig.- l), a governor sleeve 9| (corresponding to sleeve 68 in Fig. 1) and fixed to the impeller shaft 85 as indicated by a set screw 92, a pair of governor weight members 93 and 94 (corresponding to members 69 and 10 in Fig. l) hinged at 95 and 96 respectively to the sleeve 9|. and a pair of ilat spring elements 91 and 98 interconnecting the shaft 85 with the driving sleeve 99 and also acting as torque-transmitting members or coupling members between them. For 'the sake of illustration the spring elements 91 and 98 in this diagrammatic showing appear in a plane which is at right angles to the one in which they -are actually located.

In Fig. 5 the pump or impeller shaft 85 and hence the governor device C are at rest with the weight members 93 and 94 hugging the shaft, allowing the fiat spring elements 91 and 98 to urge the shaft to the right in the direction of arrow 99 thereby closing the rotary seal ring 88 upon its complementary stationary seal ring 81 to prevent leakage of liquid from the pump housing. In this rest condition the ends of each of the spring elements 91 and 98 are horizontally spaced or offset with respect to each other a distance Si.

In Fig. 6 the pump is assumed to be running and the shaft 85 to be rotating so that the weight portions of the members 93 and 94 are urged outwardly or away from the shaft 85 by centrifugal force as indicated by arrows |08 and IUI. Accordingly the foot or cam portions of the weight members engaging the face F over the driving sleeve 99 urge the shaft 85 to the left in the direction of arrow |02, thereby opening an annular passage P as the rotary seal ring 86 moves away from the stationary seal ring 81. This axial leftward shift which is on the order of M," deforms the flat spring elements 91 and 98 so that the oiset S2 between the ends of each spring element will have increased by about l/a" over the offset S1 of Fig. 5. In other words, Si appears equal to Si plus 54;". Under the Fig. 6 running condition substantially no liquid can or will leak through the passage P because of the hydraulic condition established at that point by the action of the auxiliary impeller blades 49 which draw away from this point any liquid which might tend to leak therethrough.

When the pump is stopped, parts of the governor device will return from their Fig. 6 position to their Fig. 5 position, thus closing the passage P incident to stoppage of the pump.

What we claim is:

1. A drive construction of the class described, which comprises a drive shaft having a hollow portion, a driven shaft having a portion entering the hollow portion of the drive shaft, a sleeve fixed on the driven shaft, a pivoted governor weight carried by the sleeve and adapted to have camming contact with a transverse face of the drive shaft, and a spring extending substantially transversely of the shafts and interconnecting the hollow portion of the drive shaft with said sleeve.

2. Apparatus according to claim 1, wherein the ends of the spring are offset with respect to each other.

3. Apparatus according to claim l, wherein there are a plurality of laminated springs.

4. Apparatus according to claim 1, wherein a pair of radially extending lugs are provided on the sleeve for supporting each pivoted governor weight.

5. Apparatus according to claim 1, wherein a pair of radially extending lugs are provided on the sleeve for pivotally supporting each governor weight, and one of eachpair'of lugs has a wing extending transversely of the shaft and constituting a flange portion of said sleeve.

6. A centrifugal pump comprising a base structure, a pump housing unitary with said base structure, an impeller shaft unitary with an impeller rotatable in said housing, the impeller hub having an annular sealing face complementary to a companion sealing face provided upon the housing, said sealing faces being adapted to open or close with respect to eachother so as'to open or close an annular passage defined by said sealing faces incident to an axial shifting of the shaft, a front and a rear bearing provided upon and unitary with said base structure for said impeller shaft, a driving sleeve surrounding the rear end portion of said shaft and rotatable in said rear bearing and secured against axial shift therein; automatic control means for shifting said shaft comprising a centrifugal governor device mounted upon said shaft within the space between said bearings. and adapted to shift said shaft so as to open said annular passage when the shaft is rotating by urging the shaft forwardly and in a direction away from said driving sleeve, and a pair of flat spring elements extending substantially transversely of said shaft and disposed substantially symmetrically with respect thereto with the ends of each spring element being substantially flxedly attached to the shaft and to the inner end portion of said driving sleeve respectively, said spring elements being effective normally to urge said shaft towards and into said sleeve and thereby to close said annular passage while the governor device is at rest, andsaid governor device being effective when the shaft is rotating to urge the shaft away from said driving sleeve against the resistance of said spring elements incident to a corresponding.

resilient deformation thereof and incident to said spring elements transmitting the drive torque fron'is/aid driving sleeve to said shaft.

7. Apparatus having a housing and an impeller shaft axiallyv shiftable relativeto the housing,

means carried by the shaft to open and to seal the drive shaft to the impeller shaft and of urging the impeller shaft into sealing position, and seal effecting actuating vmeans mounted on the impeller shaft and operable upon the drive shaft while the impeller shaft is rotating for shifting the impeller shaft relative to the drive shaft to open the passage against the resistance of the resiliently deformable means.

8. Apparatus according to claim 7 wherein the resiliently deformable means comprises leafl springs, and the actuating means permits return l s of the impeller shaft to close the passage when rotation of the impeller shaft stops.

9. Apparatus according to claim 7 wherein the deformable means extends substantially transversely of the' drive shaft, and the ends of the spring are offset with respect to each other.

10,. Apparatus according to claim -7 wherein the deformable means comprises a pair of laminated leaf springs with one at each side oi' the drive shaft, and the actuating means comprises a plurality of governor weights pivotally `mounted on the impeller shaft so as to be swingable in a plane extending transversely of the leaf springs.

l1. Apparatus according to claim 'Z wherein the deformable means includes a pair of leaf springs with one at each side of the shaft, and the actuating means includes a plurality of governor weights pivotally mounted on the impeller shaft so as to be swingable in a plane extending transversely of the springs, and the drive'shaft comprises a sleeve and one end of the impeller shaft enters the sleeve and is supported therein,

' and the springs are effective normally to urge the impeller shaft toward and into the sleeve to thereby close the annular passage while the governor weights are at rest.`

12. Apparatus according to claim '7 wherein the deformable means includes leaf springs, a sleeve mounted upon and associated with the impeller shaft, governor weights pivotally mounted on the sleeve, the drive sleeve having a flange at one end thereof and engaged by the governor Weights, and the leaf springs interconnected to the flange and the first mentioned sleeve.

r13. Apparatus according to claim '7 wherein the deformable means comprises at least two leaf springs, and the actuating means includes governor weights, a sleeve mounted upon and associated with the impeller shaft having radially extending lugs thereon to which each of the governor weights are pivotally mounted and supported thereby, a flange on each of the lugs extending transversely of the' impeller shaft and having one end of each of the leaf springs connected thereto, the other ends of the leaf springs being connected to the drive shaft.

ELMER R. WILFLEY. JOHN L. ALDRED. Ja.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Numcr Name Date 1,756,323 Wililey Apr. 29, 1930 1,869,824 Richter Aug. 2, 1932 2,092,351 Huntzicker Sept. 7, 1937 2,464,853 De Marco Mar. 22, 1949 FOREIGN PATENTS Number Country Date 22,504 Australia May 16, 1936 543,889 Germany Feb. 11, 1932 665,421 Germany Sept. 24, 1938 684,205 Germany Nov. 24, 1939 805,897 France Dec. 2. 1936

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