US2233269A - Vane pump - Google Patents

Description

Patented Feb. 25, 1941 f 'UNITED STATES PATENT OFFICE 4 Claims.

This invention relates generally to pumps of the type making use of displacement vanes associated with a rotor.

Conventional pumps of the vane type have been subject to certain disadvantages. For example they have been subject to vibration and excessivewear, which increases rapidly as the speed of operation is increased. Another diiiculty has been an absence of efficient operation as compared to pumps of the reciprocating type, andan inability to develop pumping pressures as high' as frequently desired. Mechanical vibration is caused not only by water hammer due to improper design, but also to the abrupt changes in pressures upon the pumping vanes, which causes a slapping of the vanes when operating at the higher speeds. Loss of eciency is due not only to friction of the working parts, but valso to a fluid slippage which necessarily greatly reduces the pumping capacity and which greatly lowers the discharge pressure which one can develop.

The present linvention has for its object the production of a vane-type pump capable of smooth operation at relatively high speeds, which will alford relatively high operating efficiency, and which will make possible the development of pressures far beyond that heretofore available with .pumps of this general class. v

A further object of the invention is to' improve Vane type pumps with respect to the manner of mounting the pumping vanes, whereby the vanes can be more accurately set with respect tothe inner periphery of the housing, and may operate with less friction, vibration and wear.

Another object of the invention is to improve pumps of the above character with respect to forming a seal with the side faces of the vanes, whereby leakage at such points is-minimized and parts relieved of wear.

Additional objects of the invention will appear from the following description in which the preferred embodiment of the invention has-been set forth in detail in conjunction with the accompanying drawings.

Fig. 1 is a side elevational View, in cross section, illustrating a pump incorporating the present invention.

Fig. `2 is a cross sectional View taken alongthe line 2-2 of Fig. l.

Fig, 3 is a cross sectional view taken along the line 3 3 of Fig. l. Fig. 4 is a cross sectional detail, showing the manner in which the two portions of the rotor are secured together, and also showing the manner in which the rotor interiits with the housing.

(Cl. S- 144) Fig. v5 is a diagrammatic perspective view, illus- ,trating more clearly the manner in which the periphery of the rotor is recessed.

Fig. 6 is a diagrammatic side elevational view ,K in cross section showing the manner in which the rotor cooperates with the cut-off area of the housing.

The pump illustrated in the drawings consists of a housing designated generally at I0, preferably formed of separate 'parts 'including the end walls II and I2, and intermediate body portion I3. The space I4 formed within the body is Vsubstantially cylindrically shaped, and is incommunication vwith the'uid inlet and outlet 'passages I'6 and I'I. These passages may connect with the external inlet and outlet pipes I8 and I9. The inner walls of the housing are recessed lor cut away, as indicated at 2I and 22, in what may be termed intake and discharge Zones, and these recesses communicate respectively with the passages I6 and I1. The segmental area 23 of the inner housing periphery, is a minor part of the inner circumference, and as willv be presently explained this area or inner surface of the housing cooperates with the rotor to form a zone or g5 area of' cut-off.

The rotor 24 is generally circular in contour, and is carried by a shaft 26 which extends from one end of the same. Asshown in Fig. 1, this shaft is'journaled within the housing extension 2'I which is formed asa part of the end wall I2, The extension 2'I may be provided with a packing gland 28 to prevent leakage about the shaft, and the outer end of the shaft may connect to any suitable source of power. There is also shown an inner bushing or sleeve 29, which can be supplied with lubricant from a suitable fitting 3E).

The rotor 24 is preferably made in two sections 24a and 24h; which are of substantially equal longitudinal extent. These parts of the rotor are inturn made separable with respect to the shaft 26, in that the rotor section 24h is attached to an annular flange 3|,.which is formed on the adjacent end of shaft 26. All of the parts of this assembly can be held together by means of the screws 32.

The pumping or displacement vanes 33 are .slidably accommodated within slots formed in the rotor 24. In order to afford a relatively liquidtight seal between the vanes and the drum,'and at the same time permit limited angular movement of the vanes with respect to the drum, each vane'is accommodated within a journal pin 34. Each of these pins is journalled within a bore 36 formed in the rotor, and each pin is provided 55 .of the vanes I make use of a stationary stud shaft 4|. The axis of this shaft is coincident or concentric with respect to the axis of the housing space i4, and the shaft may be attached to the housing end wall (See Fig. 1.) Journalled upon shaft 4| there is a bushing or sleeve 42, and the inner ends of the vanes are journalled to this sleeve, with the exception of one vane, which is attached rigidly to the sleeve. Thus as shown in Fig. 1 a ring 43 is journalled about the intermediate part of sleeve 42, and this ring is attached to one of the vanes 33. A pair cf'l rings '44 journalled upon the sleeve 42 on oppositeV sides of ring 43, are attachedto another one of the vanes. The remaining two sets of rings, designated by numbers 45 and 46, connect to the remaining two vanes. The ring 43, or one of the other sets of rings, have a rigid attachment to thesleeve 442, while the remaining rings are free to rock upon the sleeve. Thus there is little if any wear in the connection between the vanes and the sleeve 42, although the vanes are free to change their relative angular positioning. Sleeve 42 forms an adequate bearing on shaft 4|, which can be properly lubricated as by means of the lubricant duct 41.

With fairly accurate machining of the parts the vanes 33 can be so proportioned that their outer ends are spaced a slight distance from thel adjacent inner peripheral surface of the housing. Such a clearance avoids friction which would otherwise be occasioned if the vanes were permitted to thrust against the inner periphery of the housing. The desired clearance can be maintained over a long operating period because of the manner in which the inner ends of the vanes are mounted upon the shaft 4|.

Itwill be apparent from Figs. 2 and 3 that the rotor 24 is mounted to rotate about an axis which is parallel to the axis of the housing space I4, but eccentric thereto by a distance which is generally equal to :one half of the distance between the diameter of space i4, and the diameter of the rotor. Furthermore as also shown in Figs. 2 and 3 the eccentric displacement is in a plane which bi-sects the segmental area 23, Thus the vanes are projected and retracted as the rotor revolves, in a manner characteristic of pumps of this type. Either one of the passages I6 or |-1 may serve as an inlet, although with rotationin a counter clockwise direction as viewed in Fig. 3, passage` IS is the inlet and passage |1 the outlet as previously specified. The vanes are retracted as they pass in proximity to the segmental area 23', and it'is for this reason. that this areafcanbe said Ato be adjacent a zone of cut-off. The length of area 2`3 is substantially equal to the circumferential distance between the outer ends of the adjacent vanes. In other words as one vane passes the edge of area 23, another vane is leaving the edge 2, for the inlet passage |6.

Instead of forming the peripheral surfaces of the rotor toa true cylinder, the periphery is recessed between the vanes, and the recessing is unsymmetrical .for portions translated vlongitudinally ofthe axis. In other words the recessing of the periphery of rotor part 24a, differs from rotor 24h. This recessing can best be understood by reference to Figs. 5` and 6. Thus between the outer ends of any two vanes, the rotor part 24a is recessed as indicated at Sla.,

while the rotor part 24b is recessed at 5|b. ThisY recessing need not be great, and in general it is when in proximity of the area 23 forms a uid receiving pocket, and there is also an unrecessed portion 54a for the rotor part 24a, which passes in relatively close opposition to the area 23. The trailing'ed'ge 55 of each vane likewise has immediately behind it a substantially unrelieved portion, 54h of the rotor part 24h, and the recess 5|ay for the rotor part 24a.

'The'peculiar type of recessing referred to above makespossible a radically new principle of operation. Assuming that the pump is in operation in thev handling of a liquid, with turning of the rotor in a counter-clockwise direction as viewed in Fig. 3, the liquid will be drawn into the inlet passage IB; carried about the lower side of the rotor,Y and then displaced into the outlet passage |1; Assuming now that the operation is at a fair speed. The unsymmetrical recessing of the rotor between the vanes causes a surging of liquid within the region of the cut-off area 23. While it is difficult 4to give an exact graphic picture of the surges whichoccur; in general it may be pointed out that about the time the leading edge of a vane approaches the cut-off edge I, liquid from thespaceformed between area 23 and recess portion 5|a, is surging over into the recess 5|b. This crosswise Vsurge has a substantial velocity component towards the leading face of vane 33, and this component is translated into a pressure head against'the leading edge of the vane, thus preventing an abrupt change in differential pressure upon` the vane and .thereby preventing slapping. Furthermore this so-called back surge against the leading face of the vane tends to prevent leakage past the vane, such as tends to occur while the Vane is passing in proximity with the area 23. In addition to the functions specified the recessingA prevents water hammer to which vane type pumps are frequently subject,r due to trapping of liquid within the region of-area 23.

The net result of the type of recessingdescribed, irrespective of the precise accuracy of the explanation given herein, is to give smooth operation at relatively high speeds, with a great increase in pumpingl efficiency, and with the development of much higher pumping pressures. The absence of vibration contributes to minimum wear upon the working parts, and'therefore my pump is capable of long useful life, without servicing or replacement.

It will be noted (Fig.'4) that the ends of the drum are provided with annular flanges 56 having a width somewhat greater than twice the eccentricity. 'Ihese flanges are accommodated in annular recess 51 machined in the body I3 and their inner faces define side walls with which the side edges of the vanes cooperate. Thus the side surfaces with which the vanes may contact rotate in unison with the rotor, to minimize friction and wear, and also minimizing slippage.

The materials of which the various working parts are made should conform to good engineering practice. Where the liquid being handled is Water I have found that good results are Secured by making the pins 34 of a suitable synthetic composition, as for example Phenolite. This composition is capable of operating with a minimum amount of friction and wear, and Without the necessity of lubrication.

My pump is particularly adapted for the handling of Various types of liquids, or mixture of liquids and gases. It may be constructed in various sizes and capacities as desired.

I claim:

1. In a pump of the vane type, a housing formed to afford a substantially cylindrical shaped inner space, spaced fluid inlet and outlet passages formed inthe housing, said passages opening into the cylindrical space in the housing through regions located on the inner periphery of the housing, said regions being spaced by a minor segmental area of the inner periphery, a generally cylindrically shaped rotor disposed within the housing, means serving to mount the rotor for rotation about an axis eccentric with respect to said space, a plurality of pumping vanes slidably associated with the rotor, the outer ends of the pumping vanes operating in close proximity with the inner periphery of the housing, the circumferential spacing between the outer ends of said vanes being substantially equal to or less than the length of said area, the periphery of said rotor between said vanes being recessed to cause surging of iiuid Within the space between said area and the adjacent periphery of the rotor, said recessing being non-symmetrical for portions of the rotor displaced in a direction longitudinal of the axis of the rotor.

2. In a pump of the vane type, a housing formed to afford a substantially cylindrical shaped inner space, spaced iluid inlet and outlet passages formed in the housing, said passages communicating with said space through regions in the inner periphery of the housing, said regions being separated by a minor segmental area of the housing, a generally cylindrical shaped rotor disposed within the housing, means serving to mount the rotor for rotation about an axis eccentric with respect to the space, a plurality of pumping vanes slidably associated with the rotor, the outer ends of the vanes operating in close proximity with the inner periphery of the housing, the periphery of said rotor between said vanes being recessed to afford a surging of fluid in the space between said area and the adjacent periphery of the rotor, said recessing being such that for substantially onehalf the axial extentof the rotor the periphery is recessed inwardly in regions in advance of each of the vanes, while for the other half of the axial extent of the rotor the periphery is recessed in regions to the rear of each of the vanes.

3. In a pump of the vane type, a housing formed to afford a substantially cylindrical shaped inner space, said housing being provided with spaced Huid inlet and outlet passages opening into said space through the inner periphery of said housing, the region through which said passages communicate with said space being separated by an intervening minor segmental area of #the 'limer housing periphery, a generally cylindrical shaped rotor disposed within said housing, means serving to mount said rotor for rotation about an axis eccentric with respect to the axis of said space, the difference between the diameter of said space and the diameter of said rotor being substantially twice the eccentricity of the axis of rotation of the rotor and the axis of said space, the direction of eccentricity being in a plane which bi-sects said area, a plurality of pumping vanes slidably associated with said rotor, the' outer ends of said pumping vanes cooperating with the inner peripheryl of the housing, the periphery of said rotor between said vanes being recessed to cause the contour of the same to deviate from true cylindrical form, said recessing being unsymmetrical in a direction longitudinal of the axis.

4. In a pun'p of the vane type, a housing formed to afford a substantially cylindrical shaped inner space, spaced fluid inlet and outlet passages formed in the housing, said passages communicating with the space within the housing along regions located at the inner periphery of the housing, said regions being separated by a minor segmental area of the inner periphery of the housing, a generally cylindrically shaped rotor disposed within the housing, means serving to mount the rotor for rotation about an axis eccentric with respect to the axis of said space, the diameters of said space and said rotor differing by an amount substantially twice the eccentricity between said axes, the displacement of said axes being along a plane which bi-sects said area, a plurality of circumferentially spaced pumping vanes, said rotor being provided with circumferentiallyspaced slots to accommodate said vanes, means serving to journal the inner ends of said vanes for rotation about an axis concentric with the axis of said space, the outer ends of said vanes operating in close proximity with the inner periphery of said housing, axially displaced portions of the periphery Aof said rotor being recessed from true cylindrical contour, one portion being recessed near the advancing edge of each vane, and the other portionv being recessed near the trailing edge of each vane.

ATTILIO NAPOLITANO.

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