US2098652A - Rotary pump - Google Patents

Description

Nov. 9, 1937. V J c, BUCKBE 2,098,652

ROTARY PUMP Filed Aug. 13, 1935 I N V EN TOR. Jb/En C Bucieef A TTORNEYS.

Patented Nov. 9, 1937 UNITED STATES I PATENT OFFICE This invention relates to rotary engines or 2 pumps and has particular reference to the type of device in which a vane, or a plurality of vanes, is'iitted to slide radially in a slot of a rotor eccentrically mounted within a casing.

Among the main difllculties encountered in machines of this type may be mentioned internal leakage, excessive frictional wear and insuillcient or unevenly distributed lubrication.

It is the general object of the present invention to provide a simple and inexpensive rotary device of the type referred to in which the disadvantages above enumerated have been substantially eliminated.

More specifically, it is the object of the invention to provide means within such device designed to prevent internal leakage and atthe same time permit of ample, well distributed lubrication.

In the following description and in theaccompanying drawing, a device embodying the various important novel features of the invention is presented and claims are appended in which the scope of the invention is delineated.

"In the drawing:

Fig. 1 is a cross sectional side elevation taken substantially through the center of.a device em: bodying the invention, and

Fig. 2 is an end elevation of the device with the end plate removed and a member within the end plate partly broken away to disclose other interior mechanism.

The device of the invention, in the form illustrated in the drawing, comprises a substantial- 1y cylindrical casing I, ilttedwith heads 2 and 3. The heads are perforated to receive a shaft 4, and it is noticed that this shaft is eccentrically seated within the casing, as customary in devices of the kind herein considered. I

A rotor I is mounted onthis shaft and it is shown secured thereto by means of akey or .ispline t. A series of axially directed-slots I are provided in the rotor to receive a corresponding series of vanes 'i. An inlet I and an outlet I 5 arealsoprovided,for rotationoftherotorinthe direction shown by the arrow, all asusual in practice.

' It is well ism that one of themain diflicul ties with a structure of this typ isunequal'ex-r so pension of the parts. The rotor and the vanes:

must fit the casing snugly in order to prevent leakage. and this condition may be satisfactorily maintained until heat commences to developvlthin the casing. Such. heat obviously aflects :55 therotorandvanesmorequicklyandmorecomeoandvanesinterfereswiththeoperationofthe device even to the degree of freezing the rotor ends to the casing heads. If, on the other hand, sufllcient clearance is'allowed to prevent such in terference, it is found that the internal leakage is sufficient materially to reduce the efficiency of the device.

The method I employ to overcome the above mentioned difllculty consists mainly in making the rotor and the vanes shorter than the distance between the" casing heads and in freely placing annular members III, II in the spaces thus provided between these moving parts and the casing heads, furthermore in providing means for yieidingly maintaining these members pressed against the end surfaces of the rotor and vanes.

The means employed to exert pressure against themembersconveniently consist in directing a suitable pressure fluid against the annular members Iii, ii through series of pipes l2, l3, and the members are preferably made with annular recesses ll, ll through which this pressure medium is free to circulate.

The members II, II should be so much nar-- ..terengaging annularribs 25-3, and it, il

respectively, as a further means of preventing internal leakage.

The rotor is shown undercut to provide annular chambers 8", 5, communicating with the vane.

slots 8, and a lubricant, under pressure, is directed into these chambers through pipes l4, l5.

The pipes it may conveniently be bent to direct lubricant into the rotor slots 5', and the pipes l5 may be shaped to direct the lubricant into the annular spaces between the two members Ni, ii and thecasing heads. A simple, positive and effective lubricating system for-the inner working parts of the machine is in such manner provided.

From the foregoing brief description, it is seen that :the rotor and vanes never come into frictional contact with the stationary casing heads;

that the two members it, Ii, by fluid'pressure, are maintained in contact with the rotor and vanes and never come into frictional contact with the casing heads; and that the spaces between the members and the casing heads may be continuously supplied with, lubricants. Also that the vanes at-the same time are maintained lubricated. 1

It is furthermore important to note that the body portion ofthe annularmembers II, II, and

the van'es I, are substantially the same width. This leaves a comparatively large cylindrical space within the inner periphery of the members, within which space the lubricatingv Pipes I, I may be freely projected and properly directed, as above explained. If these members were carried all the way to the rotor shaft, or to cylindrical trunnions bearing on this shaft, as has heretofore been proposed, it is seen that no lubricant would reach the vane slots or the vanes.

Another important feature of this construction is the above described pressure arrangement. The pressure medium is carried into the annular grooves II), II, and these grooves are, by means of the interfltting ribs 2, I0 and 3', H separated from the cylindrical oil distributing space within the members and the undercutof the rotor. If these ribs are made to flt correctly and a sufficient number of such ribs are provided, there will be no leakage of the pressure medium into these spaces or around the outer periphery of the members to the pump chamber. The drawing is, of course, 'merely illustrative of these features, the proportions of which should be properly calculated by a competent designing engineer.

In devices of this kind, it is found that the centrifugal force throws the vanes against the inner, cylindrical wall of the casing with such force as to create excessive wear on the parts and also materially to affect the efficiency of the device due to incidental friction. In order to overcome this difficulty, I show the members III, II made with inwardly directed flanges III, II, seated to rotate in annular recesses of the casing. The inner diameter of these flanges'should be slightly less than casing diameter in order that the rotating vanes I always may bear against these flanges and thereby to relieve the pressure of the vanes against the casing wall. These flanges perform the further important function of more effectively sealing the passage from the inner working chamber of the device around the outer surface of the members "I and II. To make this sealing effect more complete, it may be well to provide one or more steps M ll in the contacting surfaces between the flanges and the casing wall. As the pressure of the centrifugal force is directed towards the peripherypf the prunp, it is readily seen that this force will tend to throw the pressure medium from the pipes I 2, I3 outward, not inward. For this reason, it is important that the step, or steps l0, H be carefully made in order that no leakagemay take place around these flanges and into the pump chamber. Conversely, the chances of the pressure medium reaching the oil chambers is slight, and the sealing devices at the inner periphery of the members I0, ll may, for this reason, be simpler.

It is now seen that, at no time does the rotor or the vanes come into contact with-the stationary casing surfaces. The members H), H, are free to floa't within the casing and they are, by contact with the rotor and vanes, due to .the force of the pressure medium, the lubricant and the centrifugal force against the vanes, caused to rotate at a speed more or less approximating the speed of these rotating parts.

The pressure fluid introduced through the pipes l2, ll may be oil, water, air' or gas, and the pressure of this fluid must be sufficient to overcome the pressure created within the device in order to maintain the members I, H in contact with the rotor and vanes. This pressure fluid may, in many instances, be obtained from the discharge port 8, or it may come from outside sources. In the drawing, conduits l6, I! are shown extendingfromthe discharge port 9 to the pipes I2, l3 for the purpose of directing the pressure fluid into the annular chambers HI, i I. Pipes l8, I9 are shown cut into these conduits to carry pressure fluid from some outside source, and valves 20, 2| are cut into these pipes. In such manner it is possible, in the first instance, to apply outside pressure and then, when sufficient pressure is attained within the device, to cut out the outside pressure supply. But the conduits l6, I! may. of course, be omitted and outside pressure entirely depended upon.

While I have herein described a preferred form of the invention, I do not wish to be limited to this precise form but reserve the right to introduce such modifications as will come within the scope of the appended claims.

I claim:

1. The combination with a casing, of a rotor, vanes radially slidable in said rotor, said rotor and vanes being shorter than the'distance between the casing heads, annular members freely seated in the spaces between the rotor and the casing heads and concentric therewith to provide within the inner periphery of the annular members a cylindrical space for receiving a lubrieating medium, there being in' each annular member an annular groove for receiving a pressure medium to maintain the annular members pressed against the rotor ends, and means for ,sealing said grooves to prevent pressure medium receiving a pressure medium to maintain the annular members pressed against the rotor ends, said annular members being made with inwardly directed flanges to arrest centrifugal movement of the vanes and thereby to reduce friction of the vanes against the casing wall,and means for sealing said grooves to prevent pressure medi leakage around the annular members.

3. In combination, a casing, a rotor, vanes radially slidable in said rotor, said rotor and vanes being shorter than the distance between the casing heads, annular members freely-seated in the space between the rotor and the casing heads to provide within the inner periphery of the annular members a cylindrical chamber for receiving lubricants, there being in each annular member an annular groove for receiving a pressure medium to maintain the annular members pressed against the. rotor ends, means for sealing said ooves to prevent pressure medium leakage, said annular membersbeing made with inwardly directed flanges seated in grooves of the casing wall to arrest radial movement of the vanes and thereby to reduce friction of the vanes against said wall, and means for sealing the inner ends of said flanges.

JOHN CALVIN BUCKBEE.

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