US2812719A - Rotary pump - Google Patents

Description

H. L. NASH ROTARY PUMP Nov. 12, 1957 4 Sheets-Sheet 1 Filed July 20, 1954 aw Y I INVENTOR. HUMP/ REY L. NAJS/r 0 21% viMcZ A 'rTORNEY- Nov. 12, 1957 H. L. NASH 2,812,719

ROTARY PUMP Filed July 20, 1954 4 Sheets-Sheet 2 IN V L TN TOR. HU/VP/YISEY 4 4/4 5/,

622% tlw A T7'OENE Y5,

H. L. NASH RGTARY PUMP Nov. 12, 1957 4 Sheets-Sheet 3 Filed July 20, 1954 INVENTOR. HUMP/{REY L A/Ajfl BY m A T TOR N675- Nov. 12, 1957 H. L. NASH 2,312,719

ROTARY PUMP Filed 'July 20. 1954 4 Sheets-Sheet 4 INVENTOR. HUMPHREY' L. NASH 06:14; ki i M embodying certain principles of my invention 2,si2,'ii9 ROTARY 'PUhtP I Humphrey L. Nash, Royalst on,I: Mass assignor of six: sevenths to Humphrey L-Nash,Jr.,-,Dhahran, Saudi Arabia, and one-seventh to John Nash II, San Jose, Calif., as trustees p Application July 20, 1954, Serial No. 444,427 14 Claims. ct ids-r23 For such purposes, andespeciallyfior-pumping ,fuel, there has been a steadily increasing demand for apump which will not cavitate and thus produce .a puls tinedelivery, and -which will be mechanically and hydraulicallyebalanced as is a centrifugal. pump but is positive: in.-its.displacement. The pump needs to betrathensmall an'ddight in weight, yet of largecapacity, It,-,should.-notrequire too high a head to obviate the-danger. of vapor. lock-.

it is, accordingly, an object ofimyinvention toaprovide a high speed rotary pump which will avoid cavitation and therefore will be non-pulsating in delivery.

lt is a further object to provide such pump which will be of the continuous central flow type and will require only a low head for satisfactory operation.

Another object is to provide such pump utilizing relative rotation of the pumping zone boundaries with relatively little vane movement being involved, and without such vanes rotating with therotor body..

Still another object is to provide-a pump having-positively acting vanes maintaining meehanicaLand-hydraulic pressure balance and affording positive displacement..

Other objects of the invention will appear as the description proceeds. t

To the accomplishment of the foregoingand related ends, said invention then comprises thefeatures hereinafter fully described and particularly pointed out in -the claims, the following description and the annexed. drawing setting forth in. detail certain illustrative embodiments of the invention,v these being indicative, however,

.of but a few of the various .ways in which the principle .of the invention may be employed.

In said annexed drawing: Fig.1 is a longitudinal section through-a rotary-pump and showingthe inner liner unsectioned; r

Fig. 2 is a transverse section taken on the line 2-2 .on Fig. 1; I

Fig. 3 is a longitudinal section corresponding to Fig. 1

.but showing the inner liner in section and thereby dis- Fig. 8 is the left-hand end view of the rotor as seen in Fig. 7;

.Fig. 9 is the right-hand view of such rotor as seen in Fig.7; 7

, Fig. 10 is a detail perspective view of one of .the vanes adapted to. be reciprocated by turning of such rotor;

Fig. 11 is. a longitudinal section taken through the rotoron the line 11-11 on Fig. 8;

Eig.,. l2 is a longitudinal section through the rotor taken on the line 12-12 at right angles to Fig. 1l; ,,Fig. 13 is; a perspective view of one of the end guide members adapted to receive the vanes of Fig. 10;

Fig. 14 is a longitudinal section through another form .of, rotary pump embodying the basic principles of my invention;

. Fig. 15 is a transverse section taken on the line onfig. l4; 7 Fig. .16 is alongitudinal section corresponding to Fig. .14 bu t,showing.the innerliner also sectioned to disclose the r otor andassociated parts;

. Fig. l7.is a transverse section taken on the line 17-17 Fig. l8 .is alongitudinal section taken on the line 18-18 on Fig. .17 through one set of ports; 1

Fig. 1-9 is a longitudinal section taken on the line 19-19 on.Eig.@ l7;

Fig, 20.;is a transverse section taken on the line 20-20 i e-p Fig. 2114's a transverse section taken on the line 21-21 on- Fig; 19;

1," Fig- 22 is a transverse section through the outlet port taken on the 1in e -22-- 22 on Fig. 19; 1

. Fig. 23 is a transverse section taken on the line 23-23 Fig. 24 is a perspective view of a-double vane or abut- ,ment member utilized in the Fig. 14 to Fig. 23 embodieat; an

is-iis ;Fig. 25 is an-endview. of such vane member indicating the,relatiye orientation or inclination of the respective van e; e nd portions. .Re fer;ring now more particularly to Figs. l-13 inclusive, the. embodiment of my invention there illustrated comprises an;outer cylindrical housing 1 having an inner peripheral-groove 2 therein communicating with outlet 3,. End plates 4 and 5 are secured to the respective ends ,ot' such cylinder by means of screws and are provided with axial openings journalling a rotor adapted to be driventhroughdrive shaft 6. Tightly fitted within cylindrical housing 1 is-an inner sleeve 7 having eight equally spaced longitudinally extending slots 8 therein with apertures 9-centrally located intermediate such slots to-place theinterior of sleeve 7 in communication with annular groove 2 leading to outlet 3. ..-The rotor comprises an axial tubular hub portion 10 journalled ,in end-plate 5 and communicating with pump inlet 11. -Integral therewith are two circular cam members 1 2-an d-- 1 3 fitting within sleeve 7 andhaving flat facesspaced apart to define a central cavity 14 (Fig.8) in communication through openings 9 with annular groove ;2 and; outlet port 3. The axially outer end faces of cams 12 .an d 13 are formed with cam surtaces adapted. to eng'a ge an d reciprocate double vanes 15 fitting inslots 45 in sleeve 7 and lying in .planes radially of the rotor. End blocks 16 and 17 non-rotatably fixed in sleeve 7 are formed with radial slots such as 18 (see. Fig. 13.) of a depth to receive the abutments proper 19. and 20 of the respective vanes 15. Rotation of the rotor consequently serves to reciprocate such vane abutments axially iii-and out of slots 18 through engagement of such abutments with-the cam faces of cam members 12 and 13.

Such cam faces may be generated by a line (a radius 3 Y of definite length) revolving around the axis of rotation of the rotor and perpendicular thereto. Such radius is caused to revolve for 45 in a primary position, then a further 45' while also moving parallelto the axis of rotation to a secondary position, then 45 in such secondary position and then 45 while moving back to its primary position, this being again repeated until a revolution is complete. As best shown in Figs. 3, 7, 8 and 9, the rotor cam members 12 and 13 are identical in their cam faces except that they are indexed to bring a high such as 21 opposite a low such as 22. Consequently, the vanes 15 will always be reciprocated positively, the vane abutment engaging a high such as 21 being entirely withdrawn within a slot 18 with the other vane abutment engaging a low such as 22 being substantially entirely withdrawn from its slot 18 and in effective pumping position.

Each rotor cam member is provided with four ports, two diametrically opposite inlet ports such as 23 and 24 leading from the interior of tubular rotor hub 10 to the axially outer cam faces where the latter are in process of dropping to the low areas 22 and two diametrically opposite ports 25 and 26 piercing the cam members to place central cavity 14 in communication with the axially outer sides of the cam members where the low regions 22 change to the high regions 21. The inlet ports 23, 24 of cam member 12 are accordingly opposite the outlet ports 27 and 28 of cam member 13 (Fig. 11) and the outlet ports 25 and 26 through cam member 12 are opposite the inlet ports 29 and 30 of cam member 13. The ports 23-24, 25-26, 2728, and

29-30 are, as shown in Figs. 4 and 7 to 9, circuferentially coextensive with the respective cam surfaces.

The faces of the vane abutments may be relieved to avoid pressure thereon as at 31 (opposite faces of the respective abutments 19 and 20 being thus relieved) and the inner edges of such abutments 32 and 33 must be beveled to afford line contact with the cam' faces of the cam members 12 and 13.

In this form of pump, the pumping zones can be any number desired. 01'' course, all other factors being equal, the capacity of the pump will depend upon the number of pumping zones. The cam surfaces should be carefully machined to provide a close sliding fit with the vanes, and the transition of the cam surfaces from the highs to the lows should be smoothly contoured.

In operation, as the rotor turns, fluid is drawn in through inlet port 11 to the interior of rotor hub 10 from which it flows radially outwardly through the ports 23, 24, 29, 30 to the respective pumping chambers containing the vane abutments 19 and 20.

Assuming that the rotor is in a position with the edges 32 and 33 of vanes or abutments in engagement with the cam faces along radial lines corresponding to the ends of the inlet and outlet ports and of the inclined or sloped portions of the cam faces (or, in other words, along radial lines corresponding to the ends of the high and low dwell portions of such cam faces), it is evident that, upon rotation of the rotor, each intake cavity defined .by three successive vanes progressively increases in size or volumetric capacity while in communication with the entire extent of the associated intake port of the rotor and thus cavitation is eliminated.

Similarly, each rotor discharge port is always in full, unrestricted communication with the associated discharge cavity defined by three successive vanes. In this way,

the pump operates without pulsation and is mechanically and hydraulically balanced.

In contradistinction, a conventional rotary pump with guided vanes carried by the rotor and engaged with the cam surface of a ported housing draws fluid through an intake port which is progressively cut off by a vane whereby the intake cavity is not completely filled with fluid and discharges fluid through a discharge port Whi h initially has highly restricted communication with the discharge cavity as a vane passes the edge of the discharge port. Such throttling of the intake and discharge of fluid results in cavitation and in pulsating delivery of fluid by such conventional pump.

Referring now more especially to the Figs. 14-25 embodiment of the invention, the pump there illustrated comprises a cylindrical housing 34 generally similar to housing 1 and having a removable end plate 35 through which rotor drive shaft 36 passes. An inner peripheral groove 37in housing 34 corresponds generally to groove 2 and communicates with the radial outlet 38. An inner cylindrical sleeve or liner 39 is fitted non-rotatably within housing 34 and is provided with eight sets of radially disposed passages 40 extending from the inner periphery of liner 39 and communicating with peripheral groove or channel 37.

Each end of liner 39 is recessed to receive rotor cams as described more in detail below. Eight cylindrical vane members 41 having pumping abutments 42 and 43 at their respective ends are pivotally mounted in eight cylindrical openings 44 extending parallel to the axis of sleeve 39 intermediate the sets of passages 40. The

central body portions of the vanes 41 are fitted within the thicker central portionof liner 39 with the abutment The rotor comprises an axial tubular portion 45 in communication"with axial inlet port 46 and in driven connection at its other end with drive shaft 36. Two

shoulders 47 and 48 fixed to tubular portion 45 -forrotation therewith fit snugly within the inner periphery'of liner 39 for rotation relative thereto and define -.-a central annular chamber 49 therebetween in communication through passages 40 with peripheral groove 37 and outlet 38.

'- Als'o mounted on the tubular rotor portion 45 for rotation therewith are two cam members 50 and 51 of general oval contour, one such cam being indexed relative to the other. The outer peripheries of such cams engage -.the flat faces of abutments 42 and 43 of the respective vane ends positively to oscillate the same as the rotor turns. Diametrically opposite inlet passages 52 and 53 extend radially'through cam 50 immediately following the diametrically opposite highs or lobe portions of the cam, communicating with the interior of the tubular rotor portion 45, and diametrically opposite inlet passages 54 and 55 similarly extend through cam 51.

Outlet passages 56 and 57 immediately preceding the highs or lobes of cam 50 extend radially inwardly from the 'outer periphery of such cam and then parallel to the axis of the rotor through annular shoulder 47 to central cavity 49. Similarly, outlet passages 58 and 59 extend radially inwardly from the outer periphery of cam 51 immediately preceding the highs or lobes of such cam, and then parallel to the rotor through annular shoulder 48 to central cavity 49.

The operation of the pump may now be clearly understood. Fluid enters main axial inlet 46, passing into the interior of tubular rotor hub 45 and thence radially outwardly through passages 52, 53, 54, and 55 to the pumping chambers immediately behind the highs of lobes of the respective rotor cam members 50 and 51. As best shown in Fig. 23, the fluid thus delivered is trapped between adjacent abutments of vanes 41 and then expelled through exhaust ports 56, 57, 58, and 59 into central annular chamber 49 from which it flows outwardly through passages 40 to outer annular channel 37 and thence to main outlet port 35. The outer ends of the ports in cams 50 and 51 lie in valleys or recesses such as 60 (Fig. 16) so that fluid may be delivered to and expelled from the pump chambers smoothly and continuously, such valleys extending to the beginning and end gs-taste A's a cam lobe engages and positively a vane abutment, this will, of course, cau's'e theab'utnient at the other end of the same vane to berock ed to eentaet the iow or following side) of mam-tote of' the ether-earn profile. As the rotor 'contitiue's to "turn, a 6 eatin of "such latter cam will noweiiga'ge aii'd pas-stately late the opposed vane abutment and 'there b'ymock't abutment at the other end of the va e torl gitto'rih tof' following contour of such lobe of the'first'caih. Tnot her words, the respective ca'm's alternately assume the bnrden of positively oscillating-anyindividualvane,

TiteFigs. 14 -23 embodiment of the invention has some practical advantages over "the Figs; 1 -13 embod ment in that-the former is rather easier to machine to 'th'e tolerlie movin arallel to the axis of rotation and "the lows, and transition zones may each neatly eiiiial division of 360. As seen above, the vanes oscillate about parallel to the axis of rotation and their abum'ient's or tips are held in contact with complementary aches er the rotor cams. g i

Referring again to the pump structures illustrated Figs. 1:13 and Figs. 1445, a notablefeatlire h reof which has been described hereinbefore, but which is deemed worthy of further emphasis; is the eeastsat' utsationless displacement of these pumps during each increment of realities of the'rotcirs therein. iiilid under pressure will be delivered-by these pumps without pulsation as long as the rotors therein are rotated at constant angiilar velocity or constant R, M. U M

In the pump illustrated in Figs. 1 12, the pulsationless displacement is achieved 1) making the alternate dwell portions 21 and 22 of the cam surfaces andz t he alternate inclined dwell joining or vaneactuatipgyortions of equal circumferential extent, (2) providing fluidjntake and discharge passages 2 324 and 2 Z -28 ofthie samc circlunifer'e'ntial extent as the inclined portions oflthe cant surfaces, and (3) spacing the cam-contacting vanes or abutments 19-2'0' c'ircu'rnfer ent ially apart a distance equal to the circumferential extents of such dwell and inclined portions of the cam surfaces. In this way, as the rotor is rotated in the pump housing 1, the displacement of the cavities defined between the rotor, the housing 1, and the vanes 19 and 20 will be constant during each increment of rotation of the rotor.

In other words, as the rotor rotates, fiuid will be displaced at constant rate from the cavities defined between the first and third ones of three successive vanes 19 and 20, said first and third vanes being held against movement by the dwell portions 21 and 22 of the cam surfaces, and only the second or middle vanes being actuated by the inclined portions but at that time the rotor intake and discharge passages 23-24 and 2728 communicate with the entire cavities between said first and third vanes.

Similarly, in the pump illustrated in Figs. 14-25, the cylindrical dwell portions of the cam members 50 and 51 are of the same circumferential extent as the alternate, relatively inclined portions therebetween and successive vanes or abutments 41 are similarly spaced apart from each other the same amount as the circumferential extent of the dwell and inclined portions aforesaid; and, furthermore, the fluid intake and discharge passages 54-54 and 58-59 in the rotor are coextensive circumferentially with said inclined or vane actuating portions of the cam members 50 and 51. Thus, the volume of each pumping or displacement cavity changes at a constant rate per increment of rotation of the rotor whereby the pump delivery will be pulsationless, if the angular velocity of the rotor is constant.

Other modes of applying the principle of the invention may be employed, change being made as regards the new, "ems-realise'niei esttaes stated-in an or following "eiaiifis', or are equivalent of "siren; "lie -etn- 'pl'oy'ed. a p I y p 4 p. "I therefore particularly point out and distinctly claim "as 'my invention; 7 v v '1. .A rotary pumpcomprisin'g a holloyv'housing, a rotor 'j oufi ialled thereinsand defining 'a chamber therewith, a series of eirctimferentiallyspaced apart vanes movably guinea, in Qsaid housing and with respect to which said fr r rotates in contact, said vanes subdividing such chamber into at least two cavities, s'ai'd rotor being termed with "a continuous vane contacting cam surface includesaltei'riate ew' u and inc1ined'portions of "substantially eiiual a'iig ular extent and etfective during rotation at said rotor to 'immovably maintain the vanes s e s'siv'e'ly 'contacted thereby in twodifferent positions an to'permit'movernent of said, vanes progressively from one such 'dwell position to the other and thenvice versa, :tlie'rot o'r contacting portions of successive vanes being part approiiimate'ly the same angle as the angular extent 'of each of. said dwell andinclined portions, said rotor being formed with fi'uid intakeand discharge passages in the respective inclined portions and co-extensive therewith, such passages communicating with the respec- 'tive cavities and spanning the space between successive vases, 7

2. The rotary of claim 1 wherein said vanes exnd generally radially ofsuch chamber and are axially n'iovabl'e therein, such cam surface being formed on an e'nd'of ""d'rotor'for contacting the corresponding end of estuaries. p

3 The rotary'piirnp of claim 1 wherein said rotor is forrn d with a duplicate cam surface, a duplicate series of itaaes are actuated by such duplicate cam surface and wherein said series of vanes and said duplicate series of varies are interconnected together for positive movement fes'poiisi veto rotation of said rotor '4. The rotary pump of, claim 1 wherein said rotor is provided with another carn v surface engaged with said series of varies said earn surfaces being e fiective to positiv'ely move said vanes" during rotation of said rotor.

5, i'o: piir'iip of, claim 1 wherein said vanes have ro'tbi' cam Sui-face contacting edges which are moved generally radially during rotation of said rotor.

6. The rotary pump of claim l wherein said vanes are mounted in said housing for oscillation about an axis parallel to the axis of rotation of said rotor and have rotor cam surface contacting edges which are moved generally radially responsive to rotation of said rotor.

7. The rotary pump of claim 6 wherein said rotor has a duplicate cam surface, wherein said vanes have duplicate edges contacting such duplicate cam surface, such edges and duplicate edges of said vanes being effective to cause a positive oscillation thereof responsive to rotation of said rotor.

8. A rotary pump comprising a hollow housing; a rotor journalled therein; a series of substantially uniformly circumferentially spaced apart vanes movably mounted in said housing and having rotor contacting edges; said housing, rotor, and vanes defining therebetween a plurality of' cavities which respectively increase and decrease in volumetric size responsive to movement of said vanes; meansfor positively moving said vanes including a cam surface on said rotor which, responsive to rotation of said rotor, progressively moves the second one of three successive vanes while the first and third ones are held against movement and thus varies the volumetric size of the cavity defined between said housing, said rotor, and said first and third vanes; said rotor being formed with fluid intake and discharge passages communicating with the respective cavities and spanning the space between said first and second vanes.

9. A rotary pump comprising a hollow housing; a rotor iournalled therein; a series of substantially uniformly circumferentially spaced apart vanes movably mounted in;

- said housing and having rotor contacting edges; said housing, rotor, and vanes defining therebetween a plurality of cavities which respectively increase and decrease in volumetric size responsive to movement of said vanes; said rotor being formed with a vane contacting cam surface which, responsive to rotation of said rotor, progressively moves the second one of three successive vanes while the first and third ones are held against movement and thus varies the volumetric size of the cavity defined between said housing, said rotor, and said first and third vanes; said rotor being formed with fluid intake and discharge passages communicating with the respective cavities and spanning the space between said first and second vanes.

10. In a rotary pump, the combination of a hollow housing, a rotor journalled therein and defining a chamber therewith, a series of at least four equi-angularly spaced apart rotor contacting vanes movably mounted in said housing and subdividing such chamber into at least two cavities, said vanes having rotor contacting edges which are adapted to be moved responsive to rotation of said rotation of said rotor, said rotor having a cam surface which engages said vanes and which, during rotation of said rotor, is effective to maintain the first and third of three successive vanes in a position of rest and to move the second one of said three successive vanes, said rotor being formed with fluid intake and discharge passages in communication with the respective cavities and spanning the space between said first and second vanes.

11. The rotary pump of claim 10 wherein said rotor is formed with a duplicate vane contacting cam surface and wherein said vanes straddle such cam surfaces and are positively reciprocated axially thereby.

12. The rotary pump of claim 10 wherein said rotor is formed with a duplicate vane contacting cam surface, wherein such cam surfaces are formed on the periphery of said rotor and are circumferentially offset with respect to each other, and wherein said vanes are oscillatorily mounted in said housing and have generally radially movable and circumferentially ofiset rotor contacting edges respectively contacting such duplicate cam surfaces.

13. In a rotary pump, the combination of a hollow housing, a rotor journalled therein and defining a cham ber therewith, a series of at least four equi-angularly spaced apart rotor contacting vanes movably mounted in said housing and sub-dividing such chamber into at least two cavities, said vanes having rotor contacting edges which engage said rotor in line contact and which are adapted to be moved responsive to rotation of said rotor, said rotor having a cam surface which is engaged by said vanes and which is effective to so move the middle one of three successive vanes while the first and third are held in a rest position, said rotor being formed with fluid intake and discharge passages which are coextensive with the spaces between successive vanes and in register with the portions of the cam surfaces etfective to move such rotor contacting edges of said vanes.

14. A rotary pump comprising a hollow housing, a rotor journalled therein and defining a chamber therewith, a series of at least four equi-angularly spaced apart rotor contacting vanes movably mounted in said housing and sub-dividing such chamber into at least two cavities which respectively continuously increase and decrease in size during rotation of said rotor, said rotor being formed with a cam surface which includes vane actuating portions and dwell portions of angular extent equal to the i angular spacing of successive vanes for actuating alternate .ones of said vanes in opposite directions and for maintaining the vanes adjacent the actuated vanes in a rest, cavity-closing position, said rotor being formed with fluid intake and discharge passages in constant communication with the respective cavities and angularly co-extensive with such vane actuating portions of said cam surface.

References Cited in the file of this patent UNITED STATES PATENTS

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