US2357778A - Supercharger - Google Patents

Description

Sept'. 5, 1944. l L. wQBEAvEN 4 2,357,778

SUPERCHARGER A l l Filed July 29,' 1942 2 Sheets-Sheet l Illl INV OR.

BY O

' ESL/E um( nPatented Sept. 5,v 1944 y i UNITED STATES 7 llfwlElar ori-ICE d n lsurnncmmmsona I d Leslie W. Beaven, Chicago, lll. Applicltlll July 29, 1 942, Seflll N0. 452,749 11 Cllllll. (Cl. 230-124) My present invention relates to devices for feeding liquid or gaseous fuel to an internal combustion engine, and more particularly my apparatus is what is termed a supercharger which contemplates the use of a forced current of air to tmpel the gaseous mixture or emulsion into the engine cylinders.

` Merely for the purpose of convenient illustration, I have herein disclosed my supercharger structure in connection with the Fuel feed device which is shown and described in my co- -pending application for Letters Patent Serial No.

that the air-currents or pressure created by the impellers are forced backward and forward in such manner as to prevent the creation of a centrifugal force, while at the same time forcing this pressure or air-currents in an inward direction to the fuel feed pipe or conduit that leads to the engine cylinders.

The impellers embody relatively -closely fitting confronting members that rotate in opposite or opposed directions so that they are adapted to thereby create a considerable amount of compression while moving at a comparatively slower speed than has heretofore been deemed necessary to generate the desired compression. This obviously results in a material saving of power as well as a reduction in wear of the parts, and vibration is diminished to a minimum. I employ adjustable yieldable means to urge the impellers constantly towards each other in a manner which permits the normal separation or clearance between the impeller members to be automatically increased by further separating said members whenever the pressure rises above the degree to which the yieldable means have been set and thus to release the excess pressure without interl a supercharger that is of novel construction, and

same yieldable means that are employed for urging the impeller membersftowards each other. This permits the mechanism to automatically take care of any sudden acceleration or reduction of speed, and it also will prevent damage to the parts of the impeller members inv the event any foreign matter accidentally enters the impellers or their associated parts. y

A feature of my supercharger is that it is entirely automatic in operation, and since itcrequires no attention it is well adapted for use in connection with the engines used in airplanes. When used in this manner, if the plane moves into a dense atmosphere, the barometrie pressure of such atmosphere will tend to increase the separation of the impellers; and when the plane moves into a thinner or more rareed atmosphere the impellers will tend to move closer together and reduce the separation or clearance between them which will increase the` elciency of the supercharger by increasing the pressure.

One of the 4aims 'of my invention is to provide which is adapted to perform its required functions in an eiective manner. Another object or aim is to provide an apparatus of the character herein disclosed that is of sturdy construction so that the parts thereof are capable of withstanding heavy duty. The apparatus, as above mentioned, ls automatic in operation and therefore requires a minimum of attention from the operator of the engine or motor.

. paratus are assembled in compact form and are fering with the continued operation of -the superi In order to provide for safety, I have incor-v porated an automatic clutch in my apparatus, said clutch being preferably controlled by the readily accessible for replacement or repair whenever necessary; the supercharger is more or less economical to produce and it is capable of being quickly assembled with the fuel feed devices of an internal combustion engine of the type mentioned herein or with other types; and it is convenient; to adjust whenever such attention is required. l-

`'I'he above-mentioned as well as othergobjects, aims, and advantages of my apparatusffgwillfgbe obvious to persons skilled in the artirftenqthe construction and operation of saidapparatusis understood from the following detailed description. It is preferred to practice my invention in substantially the manner hereinafter fullydescribed and as more particularly enumerated in the claims appended hereto, and, for a lbetter understanding of the, same, reference is madesto the accompanying drawings-that form a par of this specification. i

Inthe drawings: 'i y Figure 1 is a view partly inl side elevation?. il partly in section showing my superchargerfdevice installed upon an internal combustion rotary engine.

Figure 4 is an enlarged vertical view of one ofA the motion transmittingpinions with the adjacent portions of the supercharger structure in section.

' Figure 4a is an enlarged view, partly in elevation and partly in vertical section, showing thel slots in the pinion supporting spider.

Figure 5 is a face view presented in a fragmental manner of the left-hand impeller member shown in Figure 2. l

Figure 6 is a view similar to Figure 5 of the right-hand impellez` member shown in Figure 2.

Figure 7 is a diagram illustrating the novel manner ofl forming the blades or fins on the impeller members by means of an automatic milling machine vfor mass production.

Figure 8 shows an end of an impeller fin or blade of the preferred type.

The accompanying drawings are to be under-- stood as being more or less diagrammatic for the purpose of illustrating a typical or preferred embodiment of my novel supercharger and its various parts, and in these drawings the same reference characters are employed for the purpose'of identification of the same parts whereever they appear in the divers views.

The crank-shaft Ill of the engine, which is stationary, is preferably provided with an axial bore II through which the combustible fuel is fed to the engine casing I2 and thence to the engine cylinders I3 that are disposed in radial arrangement upon the casing. The casing and cylinders are adapted to rotate upon the stationary crankshaft IO and the hubs I4 of the casing are rotatably mounted in a rigid supporting framev I5 of any suitable construction. Anti-friction bearings IB are interposed between the engine casingv hubs I4 and the supporting frame I5,l and similar bearings I1 are interposed between the engine casing hubs I4 and the adjacent portion of the crank-shaft I0. The combustion fuel is adapted to pass through the bore II of the crank-shaft and into the engine casing I2where it will enter the inner ends of the cylinders I3 and is admitted into the combustion chambers thereof by means of suitable valved ports located in the pistons I8 which reciprocate in said cylinders and have their pitmans, operatively connected to the eccentric portion of the crank-shaft I0. O'ther details of the pistons, and associated parts, are fully disclosed in my previously-mentioned co-pending application for Letters Patent Serial No. 398,428, to which specific reference may be made` it being understood that the same is merely typical of the eng-ine structure.

The fuel feed devices and the supercharger apparatus are enclosed within a suitable housing that is mounted on the side of the support I5 which is opposite the engine casing I2. This housing embodies a cylindrical wall or shell portion I9 having lateral lugs 2li by which it is anchored to the adjacent portion of the supporting frame I5 in any suitable manner, preferably by bolts or the like` and the outer portion of said housing is closed by a concavo-convex end wall 2| that is bulged outwardly towards its center where it is thickened or enlarged to provide the inwardly projecting boss 22 that has an axially bored opening 23. The crank-shaft I0 is provided with an extension 24, the outer end of which enters the opening 23 and is secured therein by a torque key 25, and the opposite end of said extension shaft 24 is provided with an annular outer flange 26 that engages flat against the adjacent outer end of the crank-shaft I0 to which it is secured by bolts 21. This extension 24 of the crank-shaft constitutes a stationary element or xedshaft upon which the supercharger is mounted for rotational movement relatively thereto, and said extension shaft 24 is provided with an axial bore 28 of suitable diameter that is in'axial alinement with the crank-shaft boreA II to providea continuation thereof.

The fuel feed device which is assembled upon the inner portion of the supercharger shaft 24 adjacent the flange 26, preferably embodies a structure such as typified by the apparatus disclosed in my previously mentioned co-pending application Serial No. 400,811, and it is adapted to discharge a fuel spray or fog, (preferably adispersion of air in liquid fuel), into the feed bore II of the engine crank-shaft I0. The said device includes a suitable pump chamber 29 in which meshed gears 30 revolve to rapidly and finely churn the liquid fuel, received through an inlet pipe 3|, into a finely divided fog or mist which is discharged from the pressure side of the pump into the casing 32 of a control device. Casing 32 is a hollow casting, cylindrical in shape and closed at its outer'end, and having its upper cpen end entered and secured in an opening 33 in the lower segment of the supercharger shaft'24 in communication with the bore 28 thereof. An elongated piston or plunger 34 is reciprocably mounted in the casing 32 and it is of such dimensions that itsubstantially fills the bore of the casing 32 in both longitudinal and transverse directions. There is a shouldered portion 35 about midway the length of the piston or plunger 34 that is in registry with 'an annular channel 36 extending around the bore of the casing 32 which receives the dispersion of air in liquid fuel through a passageway 3'I communicating with the pressure side of the pump. A spray-port 38 is formed in the upper end of the piston or plunger 34 that is controlled by a spray-valve 39 adapted to be actuated by the pressure of the fuel received from .the pump, which fuel is transmitted to the valve 39 by a longitudinal passageway 39a. in the upper section of the piston body between the shouldered portion 35 and the chamber in which the sprayvalve is reciprocably and yieldably mounted.

The upper end of the piston 34 is exposed to and it is affected by any variations or air-pressure changes which may take place in the passageway or bore 28 of the supercharger shaft 24. The spindle 40 of one of the pump gears projects out of the pump chamber wall" and has a pinion 4I secured to it preferably in mesh with an internal annular gear 42 that is secured to the adjacent end face of the engine casing hub I4 so that said internal gear 42 will be rotated with the engine when the latter is in operation with the engine casing I2 and its cylinders rotating upon the stationary crank-shaft I0. This internal gear 42 is upon the inner surface of a'cylindrical frame or fitting 4,3 that has a spool-shape in axial section with annular outwardly extending end flanges 44 and 45, respectively, the inner flange 44 being bolted or otherwise anchored to the hub I4 of the engine casing.

An annular air-inlet opening 46 is made in the outer end portion of the supercharger shell IB, the margins of said opening having seats 41 to receive a hoop-shaped or annular lter-pad 41a of any type that may be found desirable, for

the purpose of filtering the air that is admitted through said opening, whereby to prevent dust and other foreign matter entering said shell which mmht interfere with the operation of the supercharger and other elements. Said inlet opening 46 is preferably bridged at spaced intervals by transversely disposed stays or ribs 49 that are separated from each other suitable distances to strengthen this open portion of the shell and also to preventthe lter-pad 41 being sucked or drawn into the shell by the current of air passing inwardly through said opening 45.

Within the shell there is an internal ring gear 50 that is suitably anchored to the inner surface of the shell by keys I or otherwise, and said ring gear embodies one of the members of a suitable gear 4train that is` employed to drive the impeller members of the supercharger. A plurality of planetary gears 52, (preferably two or more), in mesh with the internal ring gear 50 are mounted upon spindles 53 that are elongated to pass through the flanges 44 and 4 5 of the spool-shaped liitting or frame 43 that rotates with the engine casing. As shown in detail in Figure 2, the ends of the spindles which are remote to the gears 52 are threadedv to screw into the end of the engine casing hub i4 and they are locked in place by nuts 54.A The central or sun-gear 55 of the planetary gear train is rotatably mounted upon the stationary supercharger shaft 24 and it is in mesh with the planetary gears 52. There yis a, thrust-bearing or annular stop 56 securedy to the supercharger shaft to prevent movement of the sun-gear 55 in an inward direction towards lthe engine casing. This sun-gear 55 has a clutch disk 51, preferably formed with it, that is provided with a friction ring 58 of any suitable substance for engagement with the other or opposing disk 59 of the clu'tch device.

The impeller member 60 of the supercharger which is adjacent the clutch just before described, is preferably formed as a part of the clutch disk 59, or it may be a separate element that is attached thereto. The impeller member 6l of the supercharger confronts said member 60 and it is yieldably urged towards said member 60 so that the elements of the clutch Will normally be frictionally engaged with each other to rotate the impellers 60 and 6l uponthe extension shaft 24 through the medium of the planetary gear train when the engine is being operated in a rotative manner upon its crankshaft I0. It will be here stated that the impellers are rotated in directions that are opposed to each other, so that the required amount of compression is secured at one-half the usual/speed. The instrumentalities forperforming this function, as well as the devices which yieldably urge the clutch members into4 frictional engagement. will be fully described in a subsequent portion of this specification.

The impellers comprise the circular plates 60 and 6| that are provided with concentric rows of arcuate blades or ns 60a, and Bla, respectively, the said rows on one plate 60 being disposed in alternate arrangement with respect to the rows of blades on the confronting plate 6I, and in order to accomplishfthis arrangement.-

the rows on each plate are separated from each other by channelsv or grooves 60h and Blb that are each of proper width and depth to intimately accommodate the opposing row of blades withclose clearances between the parts. As shown in Figure 2, the clearances between the interfitting elements have been intensionally exaggerated for the purpose of avoiding confusion in the drawings.

The blades are of segmental or arcuate crosssection, preferably of an aerofoil section such as illustrated in detail in Figure 8 of the drawings, wherein it will be observed that the trailing portions ofsaid blades curve inwardly and are closer to the rotational axis of the impeller than are the leading edges which plow or cut into the air in the manner of the wing of an airplane.

The individual blades arespaced apart from each fronting impellers rotate in directions opposedr to each other, the airis forced in a somewhat zigzag or back and forth course towards the axis of rotation of the impellers, thus creating centripetal force as distinguished from the centrifugal principle upon which it has heretofore been customary to operate supercharger devices. The opposed directions of rotationrenders it possible to revolve the impellers of my supercharger at a relatively slowed-down speed las compared with the very high speed at which the present types of superchargers are rotated, with the result that Wear and vibration is reduced to a minimum without aiecting the operation of my apparatus or reducing the pressure to be attained. Furthermore, the impeller members which I have devised are capable of being rapidly produced in large quantities on automatic or semi-automatic machines due to the fact that confronting faces are alternates of each other, and the curvature of a blade in one row is, or could be, a continuation of the curvature of a blade in the next succeeding row on the same impeller member. This permits an impeller blank, after the channels or grooves 60h or SIb have been turned therein, to be mounted in a standard lathe with an automatic cross-feed and individual power-driven milling cutters to form the faces of a plurality of blades during'each sweep thereof in the manner suggested in Figure I of the drawings. Since the material used is preferably an aluminum alloy or the like, the'impellers may be machined at a very high speed and in mass production for large quantities.

The impeller members 60 and 6I have axial openings whereby said members are mounted for rotation upon the stationary supercharger shaft 24, and around these openings lI have provided facing recesses 60e and 6Ic. wliich together provide an annular central chamber 62 next to the shaft 24 to receive the compressed air which has been driven centripetally inwardly by the blades 60a and 6 la and also to provide for the mounting of motion transmitting devices that are operable between the impellers; 63a and 63h are formed upon the'impeller members 60` and 6| respectively, which said racks extend around the margins of the central chamber 62 and confront leach other in spaced relation. A ring-shaped spider 64 surrounds the stationary supercharger shaft 24 to which it is anchored by a feather-key 65 that has a rounded bearing surfacevtoarrest rotation of the spider ring. A plurality of radially disposed beveled pinions, 66 are carried by the spider so that they are in mesh with the teeth of the racks 63a and 63h, said pinions being rotatably mounted upon the smooth shanks of radially disposed bolts 51 that are screwed into the body of the spider 64.

Toothed annular. racks The spider ring 64 ls preferably provided with longitudinal slots 64a, which extend between the pinions 66 to insure passage of the centripetally driven current to the annular chamber 62. The surfaces of the impeller members 60 and 6 I upon each side of the annular racks 63a and 63h are Vtapered inwardly towards each other as shown at .1: in Figure 4, and the inner and outer endy portions 68 and 69 of the pinions are smooth and correspondingly tapered, this providing for positive bearings and for guiding said pinions 66 in a dependable manner. By means of the structure above described it will be obvious that whenever fthe engine casing is rotating, the movement thereof will be transmitted through the planetary gear'train and the clutch to the impeller member 69 and thence through the rack 63a and the beveled pinions 66 to rack 6317, thereby moving the other impeller member 6I in a direction opposed to the direction of movement of the confronting impeller member 60.

The innermost row of impeller blades, in which the curvature of the blades is substantially the same as those of the other blades, may have a tendency to spin the air into a whirlpool, creating centrifugal force opposing the centripetal force that has been created by the device, and `in order to resist this tendency, and in order t continue to force the air in an inwardly radial path, I have provided suitable means adjacent said innermost row of impeller blades for preventing a circular path of the air and thus continue the centripetalforce which has been created. These means comprise what I term a drift baille which embodies a stationary annulus or 4ring 10 that has lugs 10a secured to the spider 64 through the medium of the bolts 61. There are arcuate baiiles 1I on this ring or annulus 10, vwhich said bailies curve somewhat sharply inwardly towards the axis of the supercharger at a different tangent than the blades of the impellers 60 and 6I and in opposite directions thereto. In order to accommodate this drift baille, the innermost channel or groove of the impeller 68 is made wider as at y opposite the innermost channel or groove of the confronting impeller 6I, thus providing an annular recess in which said drift baille is disposed.

As previously stated, the impellers Gland 6I are normally urged towards each other in a yieldable manner, and control means are provided for making any desired adjustment should such be required. For the aforesaid purpose the inner portion of the inwardly projecting boss 22 is provided with threads 12 upon which a bored and threaded disk 13 is screwed, and the peripheral edge of said disk is provided with vrack teeth 14 that are meshed with the teeth of a relatively small pinion 15 that is preferably manually rotated to turn the disk 13 and move it longitudinally upon the threaded portion of the boss 22.

the shaft 24 at the hub of the impeller member I 6I. This arrangement permits the operator to adjust the tension of the spring 18 to suit conditions and requirements even though the supercharger is in motion.

Throughout the width of the chamber 62 the supercharger shaft 24 is provided with a plurality of transverse drilled apertures that establish communication between said chamber and the interior passageway or'bore 28 of the shaft, thus allowing the lcentripetally compressed air to discharge into the said bore. The throttle for controlling this discharge of air through the apertures 88 is preferably a cylinder 8| of proper outside diameter to fit snugly into passageway or bore 28 and be rotatably mounted therein so that it may be moved by the throttle lever 82 that is secured to its outer end outside the supercharger housing. A plurality of transversely extending slots 83 are made in the wall of the throttle, which said slots are adapted, upon movement of the throttle lever 82, to be registered to a greater or lesser degree with the apertures 80 in the shaft and thereby admit more or less air into the passageway 24 that leads past the fuel feed devices. The o uter end of the throttle is closed by a transverse wall 84, and said throttle is maintained in position by a cupped friction plate 85 that is anchored to the adjacent endof the supercharger shaft 24.

Above the fuel feed device and spray port there is a small hollow dome 86 which houses a coiled expansion spring 81 the tension of which is adapted to be adjusted and which has its lower end seated on a follower disk 88, in the lower open end of said dome 86. This spring is for the purpose of exerting pressure upon the piston or plunger 34 of the fuel feed devices which are axially alined with the axis of said dome 86. This spring pressure is transmitted through the medium of an adjustable toggle device 89 that has its upper and lower ends engaged respectively with the follower disk 88 and the upper exposed end of the plunger 34. ate hinged portions of the toggle are provided with right-hand and left-hand threaded nuts 80 that are respectively engaged by the correspondingly threaded end portions of a feedscrew 9| that extends through the outer end of the throttle cylinder 8l and the retainer cup 85 where it is provided with a handle 92 for operating the same. Rotation of the feed screw 8| will further separate or draw closer together the nuts 90 at the intermediate hinges of the toggle and thus make the desired adjustment of tension on the spring 81 to control the ow of fuel through the spray-port 38 into the path of the compressed air current which is moving past the spray-port in transit to the engine casing and cylinders.

It will be 4seen from the foregoing, that the type of compressor'shown is particularly suited to aeronautics, especially military, where quick dives and climbs subject the engine to rapid fluctuations' of air density, underv such stress to the personnel that manual control of the supercharger is much less satisfactory than that which is automatic. The centripetal action is well suited to coordinate the physical shape of the air passages with an important requirement of compression, the progressively increasing confinement. It permits a reduction in speed of the impellers of more than fifty percent (50%). It permits dual function of the impellers, as compressor members and as diaphragm or piston members, which, because of their large area, make the device delicately sensitive to pressure changes and quick to relieve excess pressure. with minimum movement. This feature is also The intermediuseful in graduating they degree of compression without transforming the energy of excess motion into heat. Also, injury or lbreakdown of the supercharger will not stop the engine but only the supercharging and the slipping'clutchv will become disengaged when a predetermined portion (about one-half) of the lining is worn away. This latter is accomplished by providing several stops or pins.93 that project from the shaft 24 between the clutch faces and preferably close to the face of disk 51. After the fric` tion lining 58 has worn down sufficiently, the

supercharger stop without damage to it.

In both the centrifugal and centripetal types. the air is plowed by the impeller blades to move it in the direction desired, but the essential difference between the two motions is that one is tangential, and the other is radial, and the secret of preventing development of centrifugal force is the prevention of circular motion in the air. This is accomplished-in my device by moving the air plows in opposite directions. The design of the blades makes it easy to precision machine, cast or otherwise form every surface of the airfoils and channels to the precise angle,

ring spider interposed between said impellers; pinions rotatably mounted on said spider 1n mesh with said racks, whereby movementv of one of said impellers is transmitted to the other impeller; a driving gear train; means for actuating said gear train; and a clutch operatively connecting said gear train to one of said impellers.

4. A supercharger embodying a stationary hollow support; confronting impellers rotatable in opposite directions on said support and adapted to drive air centripetally inwards towards their axes; means for admitting the centripetally driven -air into said support; annular racks on facing portions of said impellers; a stationary shape and clearance that will give maximum efciency, graduating the angle of each. row of blades to suit the requirements that are due to relative velocities of air and blade and directions of approach and recession, all of which are very desirable features in air compressing devices.

While I have described my invention in detail in its present preferred form or embodiment, it will be obvious to those skilled in the art,

' after understanding my invention, that various changes and modications may be made therein without departing from the spirit and scope thereof. I aim in the appended claims to cover all such changes and modifications.

What I claim as my invention is:

l. A supercharger embodying a stationary hollow support; confronting impellers rotatable in opposite directions on said support and adapted to drive air centripetally inwards towards their axes; means for admitting the centripetally driven air into said support; a drivinggear train; means for actuating said gear train; a clutch operatively connecting said gear train to one of said impellers; motion transmitting means interposed between said impellers; yieldably urging said impellers into intimate re lation to each other. v

2. A supercharger embodying a stationary hollow support; confronting impellers -rotatable in opposite directions on said support and adapted to drive air centripetally inwards towards their axes; means for admitting the e'centripetally driven air into said support; annular racks on facing portions of said impellers; a stationary` ring spider interposed between said impellers; pinions rotatably mounted on said spider in mesh with said racks, `whereby movement of one of said impellers istransmitted to the other impeller; and driving means having operativ connection with one of vsaid impellers. l i

3. A supercharger embodying a stationary hollow support; confronting impellers rotatable in `1 opposite directions on said support andadapted to drive air centripetally inwards towards their axes; means for removing the centripetally driven air through said support; annular racks on facing portions of said impellers; a' stationary and means -said support and adapted to drive air centripetally towards their axes; means for admitting said centripetally driven air into said hollow support; and a throttle controlling said air admitting means.

6. A supercharger and thelike embodying confronting members adapted for rotation in opposed directions; a stationary support upon which said members 4are rotatably mounted; blades on the adjacent faces of said members, said blades disposed in a plurality of concentric rows on the respective members, the spaces on the face of one member adapted to' receive the rows of blades on the face of the other member; yieldable means normally" urging said members towards each other to maintain intimate relationship between the respective rows of blades; and driving means operatively connected vto and adapted to rotate said confronting members.

'7. A supercharger and the like embodying confronting members adapted for rotation in opposed directions; a stationary support upon which said members are rotatably mounted; blades on the adjacent faces of said members, said blades disposed in a plurality of concentric rows upon each member with annular spaces between adjacent rows on the respective members, the spaces on the face of one member adapted to receive the rows of blades on the face of the other member; yieldable means normally urging said members towards each other to maintain intimate relationship between the respective rows of blades; and driving means operatively connected to and adapted to rotate said confronting members, said driving means embodying a gear train, and a clutch operatively connecting said gear train to said members.

8. A supercharger embodying a hollow support;

confronting impellers rotatable in opposite di,

provided with a fluid passage therethrough, a pair of confronting members adapted for rotation upon said shaft, there being a communication between'said passage in said shaft and the space between said members, means maintaining said members in proximity to each other, a plurality of blades carried by the proximate faces of said members and concentric with the axis of said shaft, all of said blades being obliquely disposed to a radial position, the blades of one series being of opposite obliquity to those of an adjacent series, means for rotating said members in unison in opposite directions, means for uniformly and simultaneously supplying fluid to the space between said members at their peripheries and throughout the entire circumference of the space between said members, and means for controlling at will the said communication between the passage in said shaft and the space between said members.

10. A supercharger and the like, embodying confronting members adapted for rotation in op.. posed directions and about the same axis, blades on the proximate faces of said members and disposed in a plurality of concentric rows.on the respective members, all o f said blades adapted to plow the fluid inwardly, the blades on each member rotating in the spaces between the blades on the other member, means normally urging the said members towards each other to insure a predetermined fluid pressure between said members, the last recited means being yieldable under increased pressure between the members, means for Vadjusting the last said means at will, whereby the said predetermined pressure between the members may be varied.' and means for rotating said confronting members.

11. A supercharger and the like, embodying confronting members adapted for rotation in opposed directions and about the same axis, blades on the proximate faces of said members and disposed in a plurality of concentric rows on the respective members, all of said blades adapted to plow the fluid inwardly, the blades on each member rotating in the spaces between the blades on the other member, means normally urging the` said members towards ,each other to insure a predetermined fluid pressure between said members, the last recited means being yieldable under increased pressure between the members, means for adjusting the last said means at will, whereby the said predetermined pressure between the members may be varied at any time during the cycle of operation of said confronting members, and means for rotating said confronting members.

LESLIE W. BEAVEN.

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