US2243901A - Rotary pump - Google Patents

Description

' F. C. FULCHER ROTARY'PUMP June 3, 1941.

original Filed nay 24, 1959 s shgetsheef 1 /n Venter Atta/wea l June 3;'1941. F. c. FULCHER Y 2,243,901

ROTARY PUMP i original Filed nay 24, -1939 3 Sheets-sheet 2 Fig. 2.

Elf

Fig* 3.

IO( 22 l 40 84 59: 5 '423 2 4 1 24 I 39 D 51 60 Il l2 s if; 24 D 23- 25 Mm 1MM /n venor www! wmd ttor/*7gg June3,1941. i Rc. FULCHER 1 @2,243,901

'ROTARY PUMP Original Filed May 24, 1939 I5 Sheets-Sheetl 3 [mkv 7 t c {nvgnof wd W,

Patented June 3, 194.1

Frank Christian Fulcher,

Englan gianni' Way, Pin-ley,

original application May 24, 193s, serial No. 275,454. Divided and this application April 17,

1940, Serial No. October 12, 1938 $30,224. In Great Britain iz claims. (ci. aso-.157)

The present invention relates to rotary vacuum pumps for suction-operating instruments of aircraft, and particularly for operating such suction driven flight instruments as the articial horizon, gyro-compasses and also the gyro-pilot, and preferably the invention relates to systems in which the discharge pressure is utilised for the occasional duty of operating de-icing equip-'- ment. 'Ihe application is a division out of U. S.

application Serial No. 275,454, filed May 24, 1939. y

These small capacity pumps are run at varying .speeds from 800 to as high as 4,500 with a normal or cruising speed of the order oi' 3,000 to 3,500 R. P. M., the vacuum desirable being generally from four to nine inches oi mercury inlet suction with a discharge pressure of about four inches of mercury outlet pressure when not operating, and from sixteen to Vtwenty inches of mexicury when operating, de-icer equipment. Typ of pump favoured at the present time for this duty are (a) one in which varies pass through a hollow rotor barrel, sliding through guides in the wall thereof, these vanes'extending, one through another, diametrically from one side to the other of a working chamber of a portthat upon relative rotation between the rotor and the vanes, working chambers of varying capacity are generated both inside and outside the rotor. Such a pump has hitherto been used for such heavy. duties as exhausting gases of gas plants where the pump speed -is comparatively` low, e. g., 80-150 R. P. M.` In'reduclng such a pump to the size and weight suitable for the purpose of the presentinvention and correspondingly'increasing the speedl of the pump, diillculties arise in maintaining the working chamber cool because in the known construction of this -pump the ends of the rotor barrel itself arevsupported aty opposite ends of the working chamber and end thruston the rotor also involves pressure of the barrel against the walls ofthe chamber.

In lsuch known pumps Vplain cylindrical bearings of dissimilarA materials have to be used in order to prevent undue leakage in the pump at ed cylinder whose working internal periphery is the shape oi' limacon curve. and (b) a similar` pump with a circular chamber .but in which short vanas centrifuge into contact with the working chamber. 'I'he flrst type of pump is dimcult to reproduce with uniform accuracy and is also relatively expensive. With such a construction itis notv possible to avoid that rubbing friction between thevanes and the curved wall of the working chamber as would produce undue heat and cause attenuation of the air in the pumpv and consequent loss of vacuum and also expansion of the parts which also lowers the vacuum and the second type is objectionable because of the wear and heat which is caused by the centrifuging of the vanes against the vperiphery oi the working chamber. f

According to the present invention `I operate these instruments by a pump having 'these essentia] characteristics. viz.. (1) the rotor barrel is eccentrically mounted in a cylindrical workt, ing chamber with one end thereof open'andim' truding into an annular groove in the corresponding nd wall'oi' the chamber, there being an end wall at the other end of the barrel from which projectsa shaft, (2) thefvanes rotatevabout an axiscentrally of suchfchamber where they are constrained againstfcentrifusins, (.'ilthe venes pass through slots' in cylindrical bearings inthe wallsof the rotor and (4) the casing is so ported Y,

the ends of the'rotorl barrel andvthese involve diiliculties in lubricating and cooling, the more so if these parts of the barrel were to rotateat high peripheral orrlinear speeds, andfeventually the clearances would increase by wear. Furthermore, the vgreater the diameter of the borne part and its bearing the greater is the relative expansion of the dissimilar metals due to heat set up in the neighbourhood of the bearing and undue enlargement of the clearances is likely to occur for this reason. The choice of rotor materials is also restricted .because certain light-weight metals such as Duraiumin which I may use with my pump are unsuitable as a high speed bearing material.

I must maintain fine clearances at these F- gions because the loss of vacuum involved if these clearances enlarge unduly cannot be tolerated for the purpose of my invention. 'Ihe cooling of the parts in the working chamber between which pressure cannot .be avoided, i. e., mainly between the vanes and their cylindrical bearings is another important desideratum, as also is the avoidance not only of contact between the barrel andthe casing, but also between the' edges of the vanes andthe casing-` `It is therefore essential for the punposes of this invention that thev pump should have all of the'four characteristics above enumerated and that the rotor barrel shouldV be wholly supported both radi-ally and 'against end thrust externally of the working cham-ber in such a way that the rotor .barrel andthe edges of the vanes make no contact with the walls of the working cham-ber. Therefore, according to the l present invention the rotor is supported Iboth ra` ydially and against end thrust by bearings co-operating with the shaft portion of the rotor so that between the end peripheral portions of the barrel and the surrounding portions of the end walls of the chamber there are ine ring clearances, fine clearances also being provided between the edges of the vanes and the walls of the working chamber. the clearances acting as throttling 1 seals against the loss of vacuum and being maintained not only during the normal running of the pump. but also when the pump is starting from rest and when friction heat and wear could not be avoided if the barrel itself were borne at each end. e AFine clearances are in some cases tween the ring face of the apen end of the rotor and the bottom of the annular groovein the corresponding end wall of the casing.

'I'he invention makes it convenient to use antiti'riction bearings, e. g.. ball or roller bearings, for supporting the rotor both radially vand also against endthrust, e. g., due to pressure on the closed end wall of the rotor barrel, so that pressure of the ends of the barrel againstthe wall of the working chamber is not possible. A'.li'lie anti-friction bearings support the shaft of the rotor as near Vas possible to the closed end wall of the rotor on the one distance from suchend suitably counteract the on the rotor, a suitable between the remote ends ofthe races of the two bearings is atleast equal to the length of the vanes. The rollers may run in grooves in the races of suilicientfdepth to enable the same bearing to take both the radial and the end thrust.

In this way I restrict the pressure areas to where the vanes pass through the rotor wall 'but eiective cooling is possible of the vanes and the cylindrical bearing members nrstly by a direct flow through the working chamber o! the main body of air displaced by the pump, and secondly by the continuous now of alr'through the inside wall on the other as will cantilever pressureload of the rotor barrel so that not only does the use of the inside of the rotor as well as the outside give'conslderably greater capacity for a. given size and weight than pumps of this kind which have hitherto been designedwith the working space confined to the outside of the rotor barrel. but the air being displaced within the rotor barrel has valuable cooling properties and serves to distribute the lubricant effectively. In carrying the invention into practical eiect, theV open end of the rotor may be initially inserted into the annular groove with a push or running nt, the peripheral portion of the other end of the barrel likewise being inserted with a. push or like parts of the rotor produced by such open- 'ended slotting against the natural tendency to spring outwards and distort laterally, they will be brought into position to preserve perfect cylindricity especially' when the retaining ring has been attached by multiple screws; (b) the shaft hand Vand also at such a can be machined to of the rotor is an integral projection of the end wall `of the barrel 'of the rotor and is shouldered Vto provide a .length of greater diameter near tothe end wall andthe extensionA of the casing which receives the outer races of the bearings is integral with the body of the casing and its inner cylindrical wall is shouldered to provide parts of diilerent diameters, the smaller or smallest being atthe end oi the extension remote from the working chamber. The advantages of this are, nrstly, the shaft and extension of the casing barrel portion of the rotor and lack of concendistance being onewhich running fit into the corresponding cylindrical'v wall of the casing. I may utilise allowances according to classes P to Z of table IlI of the NewallEngineerlng Company. I prefer to start with push fits so that the clearances are established in running in the pump as then the nest clearances I can obtain are made available.

To achieve the fine clearances the invention requires. precision and the pump hereinafter described is the pump must be constructed with greatk triclty incident to the use o! fastening screws or other devices is obviated and secondly, each of the bali races can be secured with the desired driving tit without contacting with the cylindrical surfaces .which receive the other races; l(c) shimming means which retain the cylindrical bearings in the barrel wall form a nne clearance between the outer surface of the end wall of the barrel and the adjacent end face of the outer race of the inner ball bearing, so providing an additional leakage-reducing mne at this end of the rotor barrel; (d) shixns and appropriate clamping means are provided with the aid otl which the desired fine diametrical (transverse) .clearances-between the end walls of the working chamber vand the venes on the one hand and the ends of the rotor barrel on the other can be obtained with especial facility. Finally, (e) the vanes are provided with hinge eyes which embrace the overhung portion of a spindle which l I do not include any such construction inthe specificationand claims hereof.

I am aware of another proposal of a pump having the four characteristics hereinbefore set forth,

but the construction as in the old form of gas ex hauster previously referred'to is such that the rotor is supported inthe working chamber and the rotor is split longitudinally and closed again by a built with this especially in view. It wiilbel found that diametral location of the parts is.

wherever possible, achieved by closely flttingcooperating cylindrical surfaces which can be machined with accuracy and that means of adjust--l 'ment to secure the transverse clearances fornil important details of the pump. Some of the important constructional features ofthe invention which contribute to the desired precision and are all embodied in the preferred formof pump retaining ring and moreover all the air displaced by the pump is compelled to passthrough the complex ports of the casing.

Brieily it may be stated that the main object of my invention is to produce a construction of pump which will permit me not only to run the rotor and vanes at high speeds out of contact with the walls of the working chamber, thereby to avoid heat and wear which' would soon have a destructive action on the vital parts of the pump, but to employ very ne clearances which will reduce slippage to true concentricity with the it is'a further object oi' my invention to provide a construction oi' pump in which although both' the vane-supporting' spindle and the rotor are overhung, i. e., supported cantilever fashion, deflection of both the vanes and the rotor will be prevented, or reduced to such a minimum that these 'iine clearances will notbe destroyed or interrupted during the running of the pump throughout the predetermined range of speeds.

Another object of the invention is to achieve the aforesaid objects whilst reducing as far as possible the size and weight of the pump by utilizing the space Within the pump to the maximum anda further object is to improvevthe cooling action by the gases being displaced on the interior parts of the pump where heat is especially liable to be generated. A Another object of my invention is to construct the barrel in such a manner that those end peripheral portions which are to make nne ring cylindricity and preservedduring running of the pump extensionl Il of the casing, this extension I! being integral with the cylindrical part la of the casing. The casing is open at the lend remote from the bearings, and a cover comprising inner and outer walls and 2|, is provided, the inner wall 20 having an annular groove 22. This groove and the bearings I1 and I8 are in axial.

alignment but are eccentric to the axis of the working cylinder. The barrel wall has slots 23 for the passage of -varies 2l of which three are shown but more could beused ifdesired. The vanes pass through slots in the cylindrical bearings which can oscillate in the slots 23 in the Another object of my invention is to facilitate I ances where established from being subsequently upset by any external maladjustment.

In order that the present invention may bei the more readily understood. I will now describe the same more particularly with the aid of the accompanying drawings, in which:

Fig. 1 is a view of-the pump and the line to the instruments, but as no novelty is claimed for the instruments per se or for the connections thereto from the pump, the layout is mainly dia-` grammatic. Fig. 2 is a side sectional elevation of the pump. Fig. 3 is a crosssectional elevation on the line III-III of Fig. 2. Figs. 4 and 5 are cross sectional views on the lines IV---IVl and V--V of Fig. 2. Fig. 6 is a sectional elevation barrel which are shaped as shown in Fig. 9 for this purpose'. The bearingsare inserted through holes 25a so that the other end seats into holes 25h in the continuous end ringl portion l2 of the rotor. Ihe bearings 25 arepreferably of a different metal from the rotor, e. g., of -phosphor bronze when the rotor is lof steel or Duralumin. The casing is preferably oi Duralumin and the vanes of steel.

The outer wall 21 of the annular groove in wall 20 is made of such diameter, as also is the cylindrical wall 28 at the other end of the casing, that the rotor barrel is inserted with a push, or a running, flt therein. and these cylindrical walls do not-participate in the support 'of the rotor, between which and the said cylindrical walls continuous fine ring clearances are permanently maintained (at any rate once .the pump has been run in), but the "rotor is wholly supported, both i radially and against end thrust by the deeply rethrough the rotor with the vanes and their bear- A Fig. 1 shows a general lay-out in which l is the pump, 2 the suction line to the instruments which are indicated diagrammatically and of which the turn and'banlr indicator is marked 3, the artificial horizon a and the directional.

gyro is 3b, whilst the gyropilot is marked lc, there usually being a suction relief valve I. A pressure line 5 leads through an oil separator 1 to de-icing equipment control valve indicated diagrammatically at 8, valve i permitting of exhaust to the slip stream when the de-icing equipment is not in use.

The pump shown in detail in Figs. 2 to 10 comprises a casing 9 containing a crescent shaped outer pumping chamber l0 having suction and discharge ports Ii, I2. the rotor Il comprising a barrel portion I4 with one end open and the other end closed by a wall I5 from which projects an integral shaft portion Il which is supported by bearings l1, Il housed in a reduced ceased-ball bearings l1, i8,'the 'inner one I] of which is located as* near as possible to the end wall il of the rotor barrel and the outer bearing Il being near Ithe remote end of the rotor shaft.

of the largebearing chosen so as to allow the latter to pass by the cylindrical wall of the opening 28 which receives the correspondingend of the barrel and to make a driving fitiwith the cylindrical wall 30 and is also shouldered down at Il to allow the outer race of a correspondingly chosen smaller ball bearing to pass freely by the walls 2l and I0 and to make a driving fit with the wall 32. The shaft of the rotor is also shouldered down at 83 to allow the inner races to be accurately assembled thereon. A spring ring!! engages in an annular groove in the shaft il and retains the bearings i'l andil and assoelated spacing means 52a in position on the shaft. A conically headed screw 86 may be used if desired (see Fig. l0) for positively locating the outer bearing race axially. By forming the rotor shaft as an integralpart of the rotor and the extension i8 as an integral parte! the casing, I avoid atthis end of the pump jointing which would render accuracy of assemblage more diiflcult and with the construction of the casing shown, I may very accurately align the rotor barrel with its bearings and the cylindrical walls 21 and 28.- Fine transverse or diametrical clearances are preferably obtained withthe aid of the 4shims hereinafter described.

From the foregoing description it follows that when the pump is in normal working condition the rotor isv radially supported solely by the ball bearings. Between the outer surface 36 of the end wall of the rotor 'barrel and the adjacent 3B are provided which retain the cylindrical bearings 25 in the rotor wall against endwise. .v

movement and prevent the rotor, particularly due to pressure on the end wall of the barrel, from pressing against the outer raceof `the ball bear ing i1, and nally they may reduce the gap between the outer surface 38 and the adjacent end face of the said outer race to a' fine clearance which acts -as a further deterrent to the leakage of air from the Working chamber to` the bearing casingor of oil from the latter rto the working chamber. End thrust is in fact taken by the ball bearings, the rotor beingkept out of contact with the casing except through the ball bearings end of the inner race 310i ball bearings-l i1 pressing against the 'cylindrical wall of the o pump chamber.

The slots 23 in the rotor barrel do not extend to the ends of the barrel but are closed at each end at '23a so as to leave integral .I and uninterrupted end` ring portions 452, @2a 4which greatly conduce to obtaining true cylin `dricity and the continuous ne ring-clearances 'betweenv those parts of the barrel Vand the wall 21 of the annular groove and wall 23l of the casing..

The method of assemblingr the vanes Yin the 4 cylindrical bearings `will not be described herein,

axial displacement by the endsl 23o of the slots 23 in the barrel Wall;

Thespindle 4| upon which the interleaving reyes or butts 39 of the rotor vanes are rotatably ble. I therefore prefer in manufacture to workl to push fits in the assemblage of the parts sov that the actual clearances are produced in the course of running 'in the pump. When these Y clearances are thus established it is ensured that they are ofv an extremely iine and lasting character and greatly contribute to countering undue loss of vacuum. The provision of ball bearings at opposite endsvof the barrel itself would make mounted is supported cantilever fashion in the walls 20, 2| so as to extend within the rotor barrel in parallelism with, but ,eccentric to, the axis of the rotor barrel, and is retained in position by a cap nut 56 which engages the threaded extremity of the spindle.

Various proposals have been made to provide a hollow barrel rotor with kthe vanes passing through slotted cylindrical bearing pins in the barrel wall, using only the crescent shaped chamber between the barrel and the cylinder wall, but for the purposes of my invention it is essential that the pump should be so constructed that the interior of the rotor is also used as a working chamberV because this enables me not only very considerably to reduce the size and weight of the pump but also to obtain a greatly improved coolthe support to the rotor shaft I have the choice of bearings andthis is for combined radial and end thrust bearings. These bearings externally of the barrel can be readily kept cool, e. g., by w packing grease in the sealed space between the,v

two bearings. Moreover, the periphery ofthe barrelof the rotor has a considerable peripheral (linear) speed which 'again makes it very undesirable to use the plain cylindrical surfaces surrounding the ends of the barrel as bearings. The varies must be supported against endwise displacement but as this is effected between the ends of the vanes and the ends 23a oi the slotsw 23 in the rotor the relative travel per'revolution at this zone is small in relation to that which occurs between the varies and the end. walls of the chamber so that as compared with theiric-` tion which would ensue if contact between such latter parts were permitted friction due to the endwise location of the vanes is small. The vanes are of light weight compared with the rotor and being borne by the small central spin-V dle do not give rise to any problem of heating and wear comparable to that which would be.

set up by using the cylindrical surfaces surrounding the end peripheral portions oi the rotor barrel as supporting bearings. The hinge eyes of the vanes may have initially a Newall hung portion 40 of a spindle 4| which is secured.

in the end walls 20,' 2| of the casing and they are thereby prevented from centrlfuging and ing action on that part of my pump where heat is most likely' to be generated, viz., where the vanes pass through the wall of the barrel.

For this purpose the inner and outer walls 2l Y and 2| are appropriately passaged and ported to -cooperate with the working chambers of varying volume which are formed in the interior of the rotor. For this purpose the annular chamber between such walls is separated by webs 59, B0 which form conduplicated recesses, one having end portionsi, B2 and the-other having end portions 6|a, 62a.

The inner wan :n isrcrmed witnwfoiir portan,

1|, 72 and 13 which, as shown more clearlyixi rv Fig. 5, are disposed across the vwall so that ports 1| and 12 lie within an area corresponding to the space inside the rotor i3, andthus communicate therewith, while ports 10 and v13 lie without the groove 22 and peripheral wall of rotor barrel I3 and communicate with the space outside the rotor i3. The ports 10, 13 and 1|, 12 may be separated from the groove by concentric arcuate additional ne throttling seal, this is not 'then essential. o

As shown clearly in Fig. 4, the outer ports 1l and 13 of inner wall 20 register with recesses 6|,

52a respectively, while the inner ports 1| and l2 v4ci' the said wall register with recesses Bla and 62 bythe cavity Il, l2 and the ports D, D being placed in communication with the discharge port 2, by the cavity Sla, 62a.

The relative sliding movement between the vanes and the rotor which is produced during the rotation of the pump generates chambers of increasing and decreasing volume both inside and outside the rotor, each of the outside chambers being dened by any two adjacent blades, the outer periphery of the rotor and the inner periphery o! the pump casing and each inside chamber being deiined by any two adjacent blades, the inner periphery of the rotor and the outer periphery of the hinge eyes of the vanes.

In a three bladed pump the maximum dlvergence of the blades is shown in the upper half of the diagram in Fig. 3 in which the chamber therebetween has attained its maximum volume and the leading vane is about to open discharge port D and suction port S and the trailing vane has just cut oif the suction port S and discharge port D'.

As the outside chamber of maximum volume is translated to the position shown in the right quarter of Fig, 3 it generates a chamber of decreasing volume on the outside of the rotor and a chamber of increasing volume on the inside the outside chamber through the discharge port I2 and drawn into the inside chamber through the suction port S', cavity 6|, 62 and ports S and Simultaneously the chamber on the outside ofthe rotor in the left quarter of the drawing (Fig 3) is ultimately translated to the position of maximum volume in the upper half of the diagram (Fig. 3) while at the same time the vanes generate inside the rotor achamber of decreasing volume in the left hand quarter oi' the diagram, whereby air is drawn into the outside chamber through the port and expelled from the inside chamber through the port D', cavity 6|a and 62a and ports 13 and I2.

When the bearings are mounted on the shaft of the rotor with shims 33 and spacing means 52a in position and the innerrace of the outer bearing held by the ring 52, the whole rotor unit with the bearings is entered into the casing, and, since the vanes as before described, are axially located by means of the ends 23a of the slots in the walls thereof, a shim 43 determines the clearance which those end edges oi' the vanes which are disposed at the shaft end oi the rotor have with the corresponding end wall of the pumping cylinder while shims 45, 65, the latter one being appropriately ported to register with the ports in the inner wall, determine the clearance between the other end edges of the vanes and the other end wall oi' the pumping cylinder and between the end ring wall of the rotor and the bottom of the annular groove 22 in the inner wall and these clearances are pre-formed, i. e., they are not formed during running-in of the pump, although the clearance between the outer longitudinal edge of the vane and the wall of the pumping cylinder is preferably formed during the running-in operation. The construction of the end wall in two parts and the means for clamping and locating the parts together will now be explained. The forming of the inner and outer spaced walls 20 and 2| of the pump in separate components is especially advantageous when the parts or some of them are to be cast owing to the rather complicated ports and passages in the end wall. The kind of pumps, with which the invention deals, run at extremely high speeds and with ne clearances and must be made with precision, a rigid and accurately assembled casingl being a first essential. In accordance with the main feature of the invention, the inner wall is l of the rotor receiving groove in the inner wall V and the opposite rotor receiving aperture in the casing' body, while the ports and passages in the end of the casing may be more conveniently made in the casting and subsequently formed with smooth walls which facilitates the flow of the gases thereover. l

The maintenance of fine clearances between the rotating parts and the walls oi the chamber l is further facilitated by my method of clamping'.

with the aid of appropriate shims. This adjustof the rotor, whereby, the air is expelled from ability is very desirable when the casing components orvsome of them have been cast and subsequently machined, so as to compensate for variations 1n the machining of the parts. Further, by arranging the inner Wall to be encircled l by the outer wall and the casing body I can dispose the shims in such a. manner that'the peripheral surfaces of the walls co-operate with a peripheral edge of the shims and serve to confine the shims against radial spread at least in one direction in the course of clamping the parts together. Intrusion of the shims into the working chamber may be particularly objectionable.

Referring more particularly to Figs. 2. 3, 4, and 5, the cover plate 2| is in the form of a disc hav- .ing a peripheral flange 2|a adapted to be fluid tightly secured to the flange 9b of the pump casing with the aid of the join'ting shim l5, and has its inner i'ace recessed and webbed to form the conduplicated recesses 6| and 62I about an inwardly projecting boss 2 |b. The cover plate 2| is adapted to be clamped to the casing by a series oi' bolts 2 spaced about its periphery.

As shown in the drawings, a radial projection 2|f extends inwards from the cylindrical face of the recess 32B and is provided with a hole for the reception of a dowel pin 2 which projects axially to enter a hole 20* formed in the outer face of the insert plate 20, thus to locate the plates 20 and 2| in their correct relative angular positions when assembled. The face of flange I9b is provided with a tapped hole into which the screw-threaded end of a dowel pin |9 is screwed so as to project axially outwards for sliding engagement in an axially aligned. hole in the face of ilange 2|". The dowel pin |9 thus serves to locate the sealing plate 2li in a. predetermined angular position relative to the pump casing 9.

The inner face of the insert plate is provided with an annular groove 22 which is eccentric to the co-axial centres of the sealing plate and insert plate, but concentric with the axis of the rotor barrel and this recess 22 receives with a ilne clearance the unsupported end of the rotor barrel, which latter rotates relatively to the insert plate.

The boss 2 |b on the cover plate is bored axially to receive the reduced extremity of a spindle 4| upon which the interleaving butts 39 of the rotor vanes 2l are rotatably mounted. The spindle 4| extends through the insert plate 20 and is thus supported cantilever fashion in boss 2|b so as to 'extend within the rotor barrel in parallelism with, but eccentric to, the axis of the rotor barrel, and is retained in position in the Aboss by a cap nut 6B which engages the threaded extremity'of'the spindle. The spindle 4| serves by its shoulder 4i* to clamp the insert plate 2l) against' the cover plateA 2| when the cap nut is tightened and to press the plates together to form a fluid tight ring joint between them with the aid of the jointing shim 65 of the desired thickness which further serves to maintain the inner face of the insert plate 20 in the desired spaced relation with the corresponding end edges of the vanes 24 and the bottom of the'annular recess 22 in the desired spaced relation with the open end of the rotor I4 when the ring joint between the flanges 2l and I9h is formed to that end.

The inner face of ange 2l* is rebated at 2id for the reception of the outer peripheral edge of an insert plate 20 which acts in a manner more particularly described hereinafter.

The ported insert plate 20, as shown in Fig. 2, is a thick disc which exceeds in diameter the bore of the pumping chamber I0, and intrudes into Ythe rebate 2id in the sealing platev 2l, and into a peripheral and end walls cooperating with each other to form a pump chamber, an annular groove in one of said end walls of said cylinder and an opening in the other end wall, said groove and said opening being eccentric to said cylinder, a rotor within said pump chamber comprising a shaft portion and a barrel portion which is open at one end and has a wall at the other, said open end comprising a ring face intruding into said annular groove and the other end of said barrel intruding into said opening in said other end wall, a spindle supported in said grooved end wall so as to project cantilever fashion into the working cylinder centrally thereof, said rotor having its shaft portion extending from one end only of said barrel, a plurality of vanes provided with bearing eyes which are rotatably, supported by said spindle and which constrain the vanes from centrifuging, slotted cylindrical bearing members oscillatable in the wall of said barrel, said chambers of varying capacity both inside and parts are mutually diametrally located. When uming between them and between the cover 2| and the insert plate 20, the latter is positioned in the desired spaced relationship with the vanes and the unsupported endy of the rotor.

By ne clearances herein referred to are meant clearances of the o rder of from one-quarter to one and a half mils orthereabouts (l mil=.0l inch). The clearances are shown exaggerated in the drawingsto facilitate the understanding of the invention.

The rotor with its bearings and the pump casing form a iinit in which' the shaft portion of the rotor is borne both radially and against end thrust. This is essential because the pump has generally to be tted to the engine shaft through the medium of a flexible coupling e. g. the laminated exible coupling 14 attached to the connecting piece 11 which is splined or otherwise formed for keying to the engine shaft. It is necessary to have the rotor properly borne both radially and against end thrust in the pump casing as the pump must be a completely operative unit in itself so as to be readily adaptable to the standard or existing engine equipment. In other Words, I do not relav on bearings of the engine to support the rotor either radially or against end thrust. 'Ihe flexible coupling 1I is not described in detail. since it forms the subject of my co-pending application Serial No. 2751456 in the specification of which a full description is to be found.

The spring washers 18 assist in sealing the interior of the pump from the engine, to the accessory pad 1 9 of which the pump is secured throughV 1. A high speed rotary vane pump comprising a casing providing a working cylinder having outside of said rotor barrel and said casing being ported to cooperate with said inside and outside working chambers, there being ne ring clearances not exceeding one arid a half mils between'the end peripheral portions of said barrel and the surrounding portions of the end Walls of the working cylinder, said clearances acting as throttle seals against loss of vacuum and being present when the pump is resting, ne

clearance not exceeding one and a half mils also being provided between the edges of the vanes and the walls of the working chambers, shimming means determining the end clearances between the rotor, vanes, and end walls of the working chambers, anti-friction bearings cooperating with the shaft portion of said rotor constructed and proportioned so as to wholly to support said rotor cantilever fashion out of contact with the working cylinder and not only radially but also against the end thrust produced by the pressures Within the pump with a rigidity suilicient to preserve circumferential continuity of Vsaid ring clearances during the running of the pump to the predetermined maximum speed and said spindle being rigidly xed to the casing so that during -portion and a barrel portion which is open at one end and has a wall at the other, said open end intruding into said annular groove and the other end of said barrel intruding into said opening in said other end wall, there being ne ring cle'arances between the end peripheral portions of said barrel and the surrounding portions of said groove and said opening which act as throttle seals against loss -of vacuum and are present when the pump is at rest, a spindle supported in said grooved end wall so as to project cantilever fashion into the working cylinder centrallythereof, said rotor having its shaft portion extending from one end only of said barrel, a plurality of vanes provided with bearing eyes which are rotatably supported by said spindle and which constrain Cil the vanes from centrifuging, slots in said barrel wall, slotted cylindrical bearing members oscillatably mounted in said slots, said barrel slots being closed at each end so that 'at each end of the barrel there are left continuous integral peripheral portions thereof, which portions cooperate with the said surrounding portions of the casing to form said ring clearances and which by their integral circumferential continuity enable said ring clearances to be of great neness, said vanes passing through the slots in said members and said members and said vanes being relatively slidable, said vanes being arranged to generate with the cylinder walls and with the inner and outer walls of the rotor barrel, pump working chambers of varying capacity both inside and outside of said rotor and said casing being ported to cooperate with said inside and outside working chambers, iine clearance also being provided between the edges oi the vanes and the walls of the working chambers, internal spacing means for adjusting the end clearances between the rotor,'

vanes and end walls of the working chambers during the assemblage of the pump components,

anti-friction bearings cooperating with the shaft portion of said rotor and constructed and proportioned so as wholly to support said rotor cantilever .fashion out of contact with the working cylinder and not only radially but also against I the end thrust produced by the pressures within the pump with a rigidity suiiicient to preserve` circumferential continuity of said ring clearances during the running of the pump to the predetermined maximum speed and said spindle being rigidly xed to the casing so that during such running, clearance shall be preserved between the edges of the vanes and the walls of the working chamber.

i 3. A rotary vane pump constructed as in claim l. in which there is a ne clearance between the ring face at the open end of the rotor barrel and ner and outer chambers are brought into correct communication with one another through the open end of the barrel, said vwalls being formed by separate components, shim means determining the axial relationship of said inner wall component with respect to said casing body so as to establish fine clearances between said inner wall component and the corresponding end edge of the vanes on the one hand and the open end of the rotor barrel on the other, further shim means determining a fine clearance between the opposite end edge of the vanes and the corresponding wall of the casing, said inner wall component having a closevperipheral t in the body of the journal the bottom of said annular groove and said shimming means determine said clearance.

4. A rotary vane high speed pump of the kind set forth for displacing air or other gaseous media comprising a casing forming a pumping cylinder and including a removable end cover at one end and having a housing at its opposite end having bearing means therein, a rotor having a barrel portion eccentrically mounted in said cylinder and a journal portion supported by said bearing means, the end of said barrel remote from said journal portion being open, vanes passing through the tubular wall of the barrel and means rotatably supporting said vanes axially of said cylinder and constraining them against pressing on the cylinder wall so that upon rotation of the rotor and the vanes the latter generate with the surface of the cylinder and the inner and outer surfaces of said barrel wall working chambers of increasing and decreasing volume both inside and outside of the barrel, said end cover comprising spaced walls, the inner wall having an annular eccentric groove in one face in which the open end of the barrel is mounted to run with a fine annular clearance with the surrounding wall of the groove and having ports connecting the said chambers and the cavity formed between said walls, said cavity being divided so that said in casing so that the inner component and said casing body are mutually diametrically located in the axial relationship determined by the shimming means so as thereby to preserve said iine annular clearance in the position of saidinner component so determined and means for clamping together said casing body so as to maintain said clearance.

5. A rotary vane high speed pump of the kind set forth for displacing air or other gaseous media comprising a casing forming a pumping cylinder and including a removable end cover at one end and having a housing at its opposite end having bearing means therein, a rotor having a barrel portion eccentrically mounted in said cylinder and a journal portion supported by said bearing means, the end of said barrel remote from said portion being open, vanes passing through the tubular wall of the barrel and means rotatably supporting said vanes axially of said cylinder and constraining them against pressing on the cylinder wall so that upon rotation of the rotor and the vanes the latter generate with the surface of the cylinder and the vinner and outer surfaces of said barrel wall working chambers of i increasing and decreasing volume both inside and outside of the barrel, said end cover comprising spaced walls, the innergwall having an annular eccentric groove in one face in which the open end of the barrel is mounted to run with a fine annular clearance with the surrounding wall of the groove and having ports connecting the said chambers and the cavity formed between 'said walls, said cavity being divided so that said inner and outer chambers are brought into correct communication with one another through the open end of the barrel, said walls being formed by separate components, shim means4 determining the axial relationship oi' said inner wall component with respect to said casing body and said outer wail component so as to establish ne clearances between said inner wail component and the corresponding end edge of the vanes on the one hand and the open end of the rotor barrel on the other, further shim means determining a fine clearance between. the opposite endedge of the vanes and the corresponding Wall of the casing, said inner wall component having a close peripheral rit in the body of the casing and in said outer wall component so that the inner and outer components and said casing body are mutually diametrically located in the axial relationship determined by the shimming means sol as thereby to preserve said iine annular clearance in the position of said inner component so 'determined and means for clamping together and having a housing at its opposite end having bearing means therein, a rotor having a barrel portion eccentrically mounted in said cylinder and a journal portion supported by said bearing means, the end of said barrel 'remote from said journal being open, vanes passing through the tubular wall of said barrel and means rotatably supporting said vanes axially of said cylinder so that upon rotation of the rotor and the vanes walls, said cavity being divided so that said inner and outer chambers are brought into correct communication with one another through the open end of the barrel, said walls being formed by separate components, means for clamping together said outer wall component and the body portion of the casing and separate means for independently clamping together said outer and inner wall components.

7. A rotary vane pump of the kind set forth comprising a casing forming a pumping cylinder and including a removable end cover at one end and having a housing at its opposite end having bearing means therein, a rotor having abarrel portion eccentrically mounted in lsaid cylinder and a journal portion supported by said bearing means, the end of said barrel remote from said journal being open, vanes passing through the tubular wall of said barrel and means rotatably supporting said vanes axially of said cylinder so that upon rotation of the rotor and the vanes the latter generate with the surface of the cylinder and the inner and outer surfaces of said barrel wall working chambers of increasing and decreasing volume both inside and outside of the barrel, said end cover comprisingspaced walls. the inner wall having an annular eccentric groove in one face in which the open end of the barrel is mounted and having ports connecting the said chambers and the cavity formed between said walls, said cavity being divided so that said inner and outer chambers are brought into correct communication with one another through the open end of the barrel, said walls being formed by separate components, a ring joint between said outer wall and the body portion of said casing, an inner concentric ring joint between said outer and inner walls, said inner joint being axially displaced with respect to said first ring joint, means for clamping said outer wall against said body portion to eil'ect said first ring joint and separate means for clamping together said outer and inner walls to eiiect said second ring joint, and said joints being clamped to leave a fine clearance between the said inner wal1 and the adjacent end edges of said vanes on the one hand and the open end of the rotor on the other.

8. A rotary vane pump of the kind set forth comprising a casing forming a pumping cylinder and vincluding a removable end cover at one end and having a housing at its opposite end having bearing means therein, a rotor having a barrel portion eccentrically mounted in said cylinder and a journal portion supported by said bearing means, the end of the barrel remote from the journal being. open, vanes passing through the tubular wall of said barrel and means rotatably supporting the vanes axially of the cylinder so that upon rotation of the rotor and the vanes the latter-generate with the surface of the cylinder f and the inner and outer surfaces of said wall of the barrel working chambers of increasing and decreasing volume both inside and outside of the barrel, said' end cover comprising spaced walls, the inner wall having an annular eccentric groove in one face in which the open end of the barrel is mounted and having ports connecting the said chambers and the cavity formed between said spaced walls, said cavity being divided so that said inner and outer chambers are brought into correct communication with one another through the open end oi' the barrel, said Walls being formed by separate' components, said inner wall component comprising a thick disc, said annulareccentric groove being formed therein, the open end of said barrel being mounted in said groove, said outer wall component and the body oi' the casing having opposed rebates, said inner wall component having a close peripheral` comprising a casing forming a pumping cylin- Y der and including a removable end cover at one end and having a housing at its opposite end having bearing means therein, a rotor-having a barrel portion eccentrically mounted in said cylinder and a journal portion supported by said bearing means, the end portion of the barrel remote from the journal being open, vanes passing through the tubular wall oi' said barrel and means rotatably supporting the vanes axially of the cylinder so that upon rotation of theY rotor and the vanes the latter generate with the surface of the cylinder and the inner and outer surfaces of said wall of the barrel working chambers of increasing and decreasing volume both inside and outside of the barrel, said end cover comprising spaced walls, the inner Wall having an annular eccentric groove in one face in which the open end of the barrel is mounted and having ports connecting the said chambers and the cavity formed between said spaced walls, said cavity being divided so that said inner and outer chambers are brought into correct communication with one another through the open end of the barrel, said walls being formed by separate components, said inner wall component having a close fit in both said outer wall component and the body of the casing so as diametrically to locate said outer wall component and said casing body, a joint between a ring face of said outer wall component and a ring face of the casing,

` said joint encircling said inner wall component and Va joint internally of said outer wall compoent and said casing bodybetween said outer and innerjwall components and means for independently clamping said joints.

10. A rotary vane pump of the kind set forth comprising a casing forming a pumping cylinder and including a removable end cover, a rotor having a barrel portion eccentrically mounted in said cylinder and having a journal portion, said barrel having its end remote from the journal open, bearing means in said casing at the end thereoi opposite to said cover, said journal being supported by said bearing means. a spindle mounted centrally of said cylinder, vanes rotatably mounted on said spindle and passing through the tubular wall of said barrel so as to be rotatable therewith and to generate with the surface of the cylinder and the inner and outer surfaces of said barrel working chambers of increasing and decreasing volume both inside and outside of the barrel, said end cover comprising spaced walls, the inner of said spaced walls having an annular groove for the reception of the open end of the rotor and having ports `connecting the said chambers and the cavity formed between said spaced walls, said cavity being divided so ing shim to confine said shim in one direction that said inner and outer chambers are brought vinto correct communication with one another through the open end of the barrel, said spaced walls being formed by useparate components;

means interposed and forming a ring joint between the outer of said walls and the body portion of said casing, means interposed and forming a ring joint between said outer and inner spaced walls, said outer wall and said casinghaving opposed rebates, said inner Wall being arranged with its margin in said rebates and out of contact with the diametral face of the rebate in the body of the casing, said Joint means serving to maintain a ilne clearance between the inner wall and the end edges of said vanes on the one hand and the open end'of said rotor on the other, said spindle having a shoulder adapted to engage the inner face of the inner wall and having a portion passing through said walls and screw-threaded, a nut engaging said screwthreaded portion for clamping said inner wall between the outer wall and said shoulder, and means for clamping together said outer wall and the body of the casing. Y

11. A rotary vane pump of the kind set forth comprising a casing forming a pumping cylinder and including a removable end cover at one end and having-a housing at its opposite end having bearing means therein, a rotor having a barrel portion eccentrically` mounted in said cylinder and a journal portion supported by said bearing means, the end of the barrel remote from the radially, and means for independently clamping said joints; i

12. A rotary vane pump of the kind set forth comprising a casing forming a pumping cylinder and including a removable end cover, a rotor having a barrel portion eccentricallyvmounted in said cylinder and a journal portion, said barrel having its end remote from thel journal open, bearing means in said casing at the opposite end tosaid coverfor supporting said journal, vanes passing through the tubular wall of said barrel,`

means rotatably supporting said vanes axially of the cylinder so that upon rotation of the rotor andthe varies the latter generate with the surface-oi the cylinder and the inner and outer surfaces of said wall of the barrel working chambers of increasing and decreasing volume both inside and outside of the barrel, said end cover comprising spaced inner and outer walls formed by separate components, said outer wall being a circular plate with an inwardly projecting peripheral ilange and a central boss, said ange having an internal rebate, webs between said boss and said flange arranged to form conduplicated cavities of the space between said walls, lsaid inner wall having an annular groove in its inner face for the reception of the open end of the barrel and having ports connecting the said chambers and the cavities formed between said walls, said outer wall :having diametrically arranged and axially l stepped inner and outer annular jointing faces,

means interposed and forming a ring-joint between the outer one of said jointing faces and the body portion of said casing, means interposed and forming a ring joint between the inner one of said jointing faces and the inner wall, said casing having a rebate forming with the rebate in said ange an annular recess in which the margin of said inner wall is situated. said joint means'serving to maintain a tine clearance between said inner wall and vthe end edges of said vanes on the one hand and the open end of said rotor on the other, and means for independently clamping said joints.

FRANK CHRISTIANYFULCHER.

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