US2264616A - Rotary compressor - Google Patents

Description

Dem- 2, 1941. J. c. BUCKBEE 2,264,616

' ROTARY COMPRESSOR Filed Sept 21, 1958 3 Sheets-Sheet l Jbfin EEL/CkbEE Dec. 2, '1941. J. c. BUCKBEE 2,264,616 7 ROTARY COMPRESSOR Filed Sept. 21, 1938 3 Sheets-Sheet 2 JU/W 5 EMS/(DEE Dec. 2, 1941. J. c. BUCKBEE 2,

I RbTARY COMPRESSOR Filed set. 21, 1938 j :s Sheets-Sheet s CEL/EkbE as any/m4 ditions.

ao'rr oonnsson.

John C. Backhoe, Los Aug-elm, Qa. Application September 21, 1938, Serial No. 23%,985

12 Claims.

This invention relates to rotary pumps and engines oi the type in which a cylindrical rotor having radially slidable vanes is eccentrically mounted in a, cylindrical casing. The particular design disclosed herein is adapted for use as an air pump but it will be understood that various features of the invention may also be employed in rotary engines and motors.

. A broad object of the invention is to provide improved lubrication in a rotary machine of the type referred to.

Another object is to reduce vibration and promote smooth operation of such devices.

Another object is to provide a practicable rotary engine or pump structure of the vane type in which an efiective fluid seal between the relatively movable parts can be readily produced and maintained.

Another object is to promote the efliciency of a rotary pump operating under varying load con- The manner in which the foregoing objects are achieved will be explained by describing in detail, with referenceto the drawings, theconstruction and operation of an air, pump in accordance with the invention, it being understood that various changes and adaptations of the particular structure disclosed may bemade without departv ing from the invention.

In the drawings:

Fig. i is a partial plan view showing in general exterior aspect an air pump constructed in accordance with the invention;

Fig. 2 is a vertical longitudinal section through thepump, the section being taken in the plane H-H oi Fig.1;-

Fig. 2A is a sectional view similar to Fig. 2,

v but on a larger scale and showing only one endportion of the pump;

Fig. 3 is a cross section through the pump taken in the plane I11.lII of Fig.1; and

Fig. 4 is a detail inside face view of an adjusting end plate of the unit.

Referring to the drawings, the air pump therein disclosed comprises a. casing member I of roughly cylindrical shape, which is stationarily supported on a suitable base 2 and is provided with an'inner cylindrical surface 3 constituting one of the walls of a compression chamber. .For

convenience the member i will'hereinafter be referred to as the stator. The stator I may be provided with a water passage t for cooling purposes.

The opposite ends of the stator l are closed. A by heads a and .8. respectively, which may be bolt- 55 line. it in Fig. 3), at an angle to the horizontal,

which in turn rotatably support a shaft l on which a cylindrical rotor 8 is mounted, the rotor being positioned eccentrically within the casing 5' 3. The heads 5 and 8 may also have passages 3 therein for the circulation of cooling liquid.

The rotor 8 is of smaller diameter than the inner surface 3 of stator i and is positioned eccentrically within the statorso that its periphery approaches very close toth'e inner surface 8 of the stator i at one point so as to provide for effecting a, fluid seal between the rotor and casing along the line where they most nearly approach. The rotor 8 is provided with a plurality of radial slots t extending, from end to end of the rotor, in which slots there are slidably mounted vanes I0. In operation, the rotor is rotated at relatively high velocity so that the vanes it are urged outward toward the inner surface 3 of'the stator by centrifugal force. The stator i is provided with an inlet port it on one side and an outlet port :2 on the other side so that when the rotor is rotated in clockwise direction (referring to Fig. 3), the air or other gas to be pummd, which enters through the inlet port it is trapped in the pocket created between the vanes it and between the surface of the rotor and the surface 3 of the casing, and is carried around-with the rotor and compressed as the rotor surface ap- 30 proaches the casing surface, and finally discharged through the port 12.

Insofar as the general structure so far described is concerned, it is in accordance with the general type described is that they tend to vibrate due to the fact that under varying conditions of load,

varying radial forces are applied in different directions to the rotor. Thus under conditions of 40 no load the chief force acting upon the rotor is.

gravity, which of course exerts a downwardly directed force. On the other hand when a pump of older design of the type described is working, new forces are developed which act radially on the rotor in directions other than downward, so that they oppose the force of gravity, some times exceeding it, and at other times being less than it. These varying radial forces tend to shift the rotor and shaft. throwing undesirable strain on the bearings and often causing severe vibration.

In accordance with the present invention, I

greatly reduce the vibration resulting mm the 1 with the line of closest approach of the rotor to the casing closely adjacent to the lower part of outlet port l2. With this construction the forces resulting from the compression of gas between the upper surface of the rotor and the juxtaposed surface of the casing act in a general downwardly direction on the rotor, thereby holding the rotor shaft firmly in its bearings, avoiding vibration and chattering in the bearings, and giving a smooth, quiet-running machine.

The fact that the compression of the gas takes place on the upper side of the rotor also facilitates free entry of air or gas into and out of the machine, further reducing vibration of the machine by minimizing eddy currents of air or gas within the machine and contributing to its smooth operation and efliciency. Other advantages of the particular orientation of the rotor as shown will be discussed later in connection with the lubricating system of the machine.

In a machine of the type disclosed, it is desirable that the ends of the rotor and the vanes be liquid sealed with respect to the casing as well as that the outer edges ofthe vanes 10 be so sealed with the. inner surface 3 of the casing. Heretofore, to the best of my knowledge, it has been the practice to carry the ends of the rotor out to contemplated running clearances with the heads of the casing, the actual clearance in operation being determined by the thickness of the gaskets placed between the ends of the cylindrical casing and the heads, and by the extent to which the bolts holding the heads in place were tightened. This was obviously a crude and uncertain method of construction where clearances measured in thousandths of an inch must be secured and maintained to secure efficiency.

In the machine disclosed, I permit of accurate adjustment of the clearance between the ends of the rotor 8 and vanes l and the abutting surfaces of the casing by providing separate inner head members l and I6, respectively, which are slidably mounted in counterbores I1 and I8, respectively, in the opposite ends of the casing member 3. These counterbores extend inwardly from the ends of the casing 3 substantially beyond and into overlapping relation with the ends of the rotor B. The heads I5 and I6 are provided with apertures l9 and 20, respectively, for the passage of the rotor shaft 1 and for admitting lubricant to the vane slots 9, and are machined to closely approach the end faces of the rotor and the ends of the vanes H! to provide for effecting a fluid seal therewith.

As previously indicated, the inner heads l5 and I6 are slidably mounted within the counterbores I1 and I8 and must therefore be retained in desired longitudinal positions with respect to the shoulders of the said counterbores and the rotor 8. I provide for accurate longitudinal adjustment of the inner heads I5 and I6 and the locking of the said heads against outward movement from thedesired position of adjustment by means of several plungers 2| which are disposed at convenient circumferential intervals back ofv heads 15 and I6, and extend through longitudinal apertures provided therefor in the outer heads 5 and 6, respectively, into abutment with the outer faces of the inner heads l5 and I6. The outer ends of the apertures in the' heads 5 and 6 which receive these plungers 2| are threaded to receive screws 22, the inner ends of which screws bear against the outer ends of the plungers 2|. It will be obvious that by adjustment of screws 22 the heads [5 and I6 may be adjusted to desired longitudinal positions within said counterbores and maintained against outward movement from those positions.

To limit inward movement of the heads l5 and 16 from their positions of desired adjustment, each of the heads l5 and I6 is provided with a peripheral flange 23, the inner end face of which seats against an adjustment ring 24 which'in turn seats against the shoulder-at the end of the counterbore H or I8, as the case may be. By suitably choosing the longitudinal thickness of the rings 24 and adjusting the screws 22 to force the inner heads l5 and I5 up snugly against the rings 24, the desired accurate clearance between the ends. of the rotor and the heads l5 and I6 may be readily obtained. The clearance necessary in any particular case will depend to a large extent upon the temperature variations in the pump, which cause varying expansion of the parts, and pumps constructed as described can be adapted for different conditions of operation involving different operating temperatures by merely changing the spacer rings 24.

It may be desirable in many instances to form the plungers 2| of a material having a greater rate of expansion for a given temperature rise than the stator material, so that after the machine has been started cold'the increase in temperature during operation increases the pressure of the plungers 22 against the inner heads l5 and 16.

The adjustment rings 24 have their inner surfaces flush with the surface 3 of the stator. The spaces within the flanges 23 are provided with accurately machined floating rings 25 which receive the radial thrust of the vanes 10 due to centrifugal force, and rotate with the vanes. The floating rings 25 within the flanges 23 are bored slightly smaller in diameter than the stator surface 3 and the blades ID are thereby held clear of the stator surface 2 when the machine is in operation, and wear between the vanes and the stator surface 3 avoided. Floating rings have been used before to limit outward movement of vanes in rotary machines of the type with which this invention is concerned, but to the best of my knowledge it has been the practice in the past to position such rings in counterbores in the stator some distance in from the stator ends, which construction requires theplacing of stationary rings between the floating rings and the end heads to complete the stator bore from the floating rings out to the end heads. Such construction was objectionable in that it was expensive and in a measure uncertain as to the degree of clearances obtainable. By placing the floating rings 25 at the endsof the rotor 8 within the flanges 23 of the inner heads I5, I provide a very simple construction for obtaining very accurate and definite clearances. Thus it is merely necessary, prior to insertion of the heads l5 and I6 into the stator, to position the floating rings 25 within the flanges 23 and check the widths of the rings 25 by observing whether their end faces are clear of the end faces of the flanges 23. If they have the clearance required for successful operation, it is then known that when the inner heads and rings are assembled in the stator the longitudinal clearances at the edges of the rings will be correct.

In the pump as so far described, the inner end walls l5 and I6 are fitted to very close clearances with the ends of the rotor and vanes. However the interior end walls l5 and 16 are not intended to take any thrust that may be apaccepts 3 plied by Justable porting the tudinal displacement.

I prefer to employ antifriction bearings for supporting the rotor, and to facilitate adjustment and provide for longitudinal expansion of the the rotor, and I provide a readily adbearing construction for accurately suprotor, I employ a longitudinally adjustable com-1 bined radial and thrust bearing at one end and a radial bearing only at the other end of the rotor.

Referring to Fig. 2, the radial. bearing is positioned at the left end of the rotor 8 and is of the roller type; thus it comprises an inner race .21 mounted on the rotor and rigldlysecured in position against a shoulder 28 on the shaft by.

a nut 29 threaded onto the shaft. The race 2'!v is provided with an annular recess the sides of which bears against the ends of a plurality of cylindrical rollers 39 which may be confined in a cage in accordance with the usual practice. The rollers 3d bear against a stationary outer race 3! which is cylindrical on its inner surface so that the rollers 3@ can move freely longitudinally with respect thereto. The race 3i is clamped in the outer head 5 of the pump by a closure member 32, which closure member alsoincorporates packing material 33 and a packing gland 3 for effecting a seal about the shaft F. It will be observed that this hearing rotatably supports the shaft 7 against any radial movement but permits free longitudinal movement between the rollers 88 and the outer race 3t. r

The hearing at the other end of the rotor (the right end in Fig. 2) is adapted to resist both radial and longitudinal movement of the rotor while permitting free rotation thereof, and, as shown, is of the hall type. Thus it comprises an inner race 35 rigidly clamped on the shaft 5 against a shoulder thereon by a nut 37. The outer surface of the inner race 35 is grooved to receive a ring of balls 38 which also fit in a juxtaposed groove in the inner wall of an outer race 39. By virtue of the grooves in the inner and outer races, the races are restrained against longitudinal as well as radial movement with respect to each other. The outerrace. ts-i rigidly secured by a threaded bushing at in a cage (ll,

which cage is provided with an outer cylindrical surface at ground to slidably fit in a cylindrical recess in the head 5. Adjacent its outer edge the cage t! is provided with exterior threads 45 and cooperating threads are provided on the inner surface of the recess in the head 6 at its outer end. Therefore by rotating the cage 6i the cage and the ball hearing may be shifted longitudinally to adjust the rotor 8 to the desired position oi clearance with'respect to the inner heads i5 and 65, respectively.

To look the cage M in a desired position of adjustment a pin t3 is provided in the bushing dd, this pin projecting longitudinally from the bushing into one of a plurality of recesses provided in. an end plate M which closes the end of the head 6. It is to} be understood that the bushing dd, after being screwed up tight against the outer race 39, is locked against further rotation with respect to the cage M, as by passing a pin dta through registering apertures in the cage and bushing. Hence the pin 43 restrains the bushing from rotation and the bushing in turn restrains the cage ill from rotation.

Referring to Fig. 4, which is a view of the innerface of the closure plate 5d, it will be obrotor against both radial and longivided in the plate for reception of the pin 53 so that the cage 4| can be locked at such position as longitudinal adjustment of the rotor may require. Longitudinal adjustment of the rotor to the desired running position is effected by remov,-.

ing the cover plate 44 and rotating thecage 4| in one direction until the end of the rotor bears against one of the inner head members IE or it. The cage 4| is then rotated in the opposite direction until the rotor bears against the other inner head.- Then either by micrometer gauge rea'dings or through knowledge of the number of threads per inch on thecage and observing the angle through which the cake M has been t d in the above operation, the total clearance between the ends of the rotor and the faces of heads I5 ii the and It may be readily determined as well as the relative position of heads 55 and it with respect to the rotor, and it is then merely a matter of again rotating cage dl to move the rotor longitudinally until the desired running clearance at the rotor ends is obtained. after which case ti is looked through the medium of pin t3.

When a pump of the type described is rotated continuously to supply a varying demandjand the demand decreases, the pressure in the discharge port rises beyond the desired value and lessly wasted. I avoid this objectionable feature by providing a special valve system for cutting oiithe supply of air to the pump and venting the discharge side of the pump to the atmosphere whenever thepressure in the discharge port exceeds a desired value.

Thus referring to Fig.3, the inlet passage i l. leading into the stator l, communicates throu h a plurality of ports he with a central passage 5! which in turn is connected-at its upper end to an intake pipe 52. A piston valve 53 is slidably fitted in the passage ti and may be provided with piston rings 56 at its upper and lower edges for effecting 'a fluid-tight seal against the walls of the passage 5!. When the valve 53 is in lowermost position, as shown in Fig. 3, its upper end is substantially flush with the lower edges of the ports, so that the pipe 52 is in free communication with the intake passage it. However, when the valve 53 is in uppermost position in the passage iii, it is juxtaposed to the ports 58 and blocksthe -iiow of air therethrough. The valve 53 normally remains in the lowermost position shown in Fig. 3, in which the ports, 56 are open. When it is desired to close the ports lid the valve 58 is raised to its uppermost position by introducing fluid under pressure to the passage 51' below valve 53.. The fluid employed for liftserved that a plurality of apertures 68 are pro- 75 log the valve 53 may be air under pressure from the discharge side of the pump. and is delivered through a pipe under the control of a valve mechanism next to be described.

Referring to Fig. 3, the discharge passage 02' in the stator I communicates through an orifice 58 with a chamber 57 having a discharge passage 58 extending from the .upper side thereof into communication with. a discharge pipe 59. A

check valve 80, which is urged into closed position by a spring 5|, serves to cut the passage 58 oil from the pipe 59 in response to any return how of air. The'passage 58 is incorporated in a block 62, which also has formed therein, to one side of the passage 5d, a cylinder 63, which slidably contains a piston element 64. .A'second piston element is'attached to and spaced above the piston element 66, the two being formed in- Y tegral with each othenand with a push recite punfp continues to work, power is need-.

' At the same time extendingbelow the piston 64. The pistons 65 and 65 are normally maintained in an upper position, as shown in Fig. 3, by a short arm 61 supporting a roller 6.8, which bears against the lower end of push rod 66. The short arm 61 is attached to a shaft ll journaled in bearings in the block 62, as shown in Fig. l. The shaft II also has attached to it a long arm 69 carrying a weight 10. A short stop arm 12 is attached to the shaft II for limiting downward movement of the short arm 61.

A passage 15 connects the discharge pipe 58 permanently with the upper end of cylinder 63, and a passage 16 permanently connects the passage 58 with the cylinder 63 at a point in the latter juxtaposed to the piston 64 when the latter is in uppermost position, as shown. A ventcommunicates the central portion of the cylinder 83 with the atmosphere under normal conditions. A pipe 55 also communicates with the cylinder 63 at a point a short distance above the vent 11.

Under normal conditions of pump operation, 8

and 65 occupy the positions shown in Fig. 3, and the arm 69 occupies the position shown in full lines in Fig. 3. Under these conditions pressure in the discharge pipe 58 is applied through passage 15 to the upper end of piston 65, tending to force the piston down, against the force exerted thereon by the weight 10 acting through arm 68, shaft H and the short arm 81, and the piston 64 seals the outer end of the passage 16. The condition described will obtain whenever the pressure in the discharge pipe 59 is insufficient to overcome the force of the weight 10, and with the pistons 65 and 64 in the upper position shown, the passage 15 is sealed and the pipe is connected to the vent 11 so that atmospheric pressure exists below the inlet valve 58, permitting the latter to remain in its lowermost position and air to flow freely into the inlet When the consumption of air supplied through the discharge pipe 59 is reduced so that the pressure rises sufficiently to force the pistons 65 and 64 downwardly, thereby swinging the arm 68 into the position shown in dotted lines in Fig. 3, the downward movement of the pistons carries the upper edge of the piston 65 below the passage communicating with the pipe 55, and carries the upper edge of the piston 64 below the passage 16. Therefore air under high pressure from the discharge pipe '59 flows through'passage 15, the upper end of the cylinder 63, and into andthrough the pipe 55 to raise the intake valve 53 into uppermost position, in which it closes the ports 50. This cuts off the supply of air to the intake passage H and the compressor ceases to pump air. the movement of the piston 64 communicates the passage 16 with the vent 11 so that any pressure in the outlet passages l2 and 56 and the chambers 51 and 58 is relieved. It is understood, of course, that as soon as flow ofair from passage 58 to the discharge pipe 59 ceases, the check valve 60 closes to prevent return flow.

When the pressure in the dischargepipe58 drops below an amount suflicient to overcome the force of the weight 10, the weight I0 swings the arm 69 back into the full line position, raising the pistons 64 and 65 into uppermost position, in which the pipe 55 is vented to the atmosphere, and the passage 16 is closed. Thereupon the inlet valve 53 drops into lowermost position, opening the ports 50, and the pumping operation is the pistons 64 resumed.

It will be observed from Fig. 3 that the normal position of the long arm 69 extends upwardly and outwardly from shaft II at a relatively large angle from the vertical, but that in the dotted line position the arm 69 makes a much smaller angle with the vertical. Obviously the torque applied to the shaft II by the weight 18 is substantially greater when the arm 69 is in the full line position than when it is in the dotted line position. Hence a substantially greater pressure in the discharge pipe 59 is required to stop the pumping action than to resume it. This is desirable because it prevents unnecessarily frequent starting and stopping of the pumping action. Thus the above described controlling device may be adjusted to cut out the pumping action when the terminal air pressure in the discharge pipe 59 reaches, say, 35 pounds per square inch and not cut in again until the pressure falls to 30 pounds per square inch. Various desired differentials between the pressure required to stop the pumping action and that permitting resumption of the pumping action may be obtained by adjusting the radial position of the arm 69 on'the shaft H. As shown in Fig. 1, the arm 69 is locked to the shaft 'II by a set screw 19. By loosening the screw 19 the radial position of the arm 89 relative to the shaft H may be altered to vary the relative pressures at which the compressor cuts in and cuts out of service.

In a rotary compressor, particularly compressors operating at high speeds, it is essential to provide a positive supply of oil to the various working surfaces in order to reduce friction and in many parts to help maintain a seal.

The present invention incorporates a novel and particularly effective oiling system which will now be described.

Referring to Figs. 2 and 3, there is mounted on the upper side of the stator i, an oil reservoir which, as shown, happens to be secured to the stator by a water pipe 8| which extends downwardly therethrough and communicates with the water passage 4 for cooling the compressor. However, there is no communication between the interior of the water pipe 8| and the reservoir 88, the pipe 8| functioning only to retain the reservoir in position. The reservoir 80 supplies oil, through a valve mechanism, later, and a pair of pipes 82, to opposite ends of the compressor. Each pipe 82 is connected through a sight feed regulating valve 83 and an elbow 84 to a conduit 85 extending through the end members 32 and 44, and the outer heads 5 and 6. Thus the conduits 85 terminate in orifices 86, 86 which are positioned within the openings l9 and 20, respectively, in the inner heads l5 and [6, respectively. These orifices 86 at the discharge ends of the conduits 85 face in the direction of the windage stream created by the rotor and are so shaped that the windage created by the rotor tends to suck or draw oil fromthe conduits 85.

When the compressor is in operation, oil flows by gravity from the reservoir 80 through the pipes 82 and the sight feed regulating valves 83 and through the conduits 85, and is discharged through orifices 86 into the annular spaces I9 and 20 in heads [5 and I6. The rotor is provided at each end with an annular groove 81 which extends to the bottoms of the vane slots 9. The oil therefore flows from the annular spaces I8 and 20 into the annular grooves 81 and thence into the slots back of the vanes as the vanes move outwardly in the slots, and later, when the vanes to be described openers lubricate the ends of vanes I and to help seal the ends of the rotor and the surfaces of heads I and it.

,A baflie plate 88 is preferably positioned on the outer surface of each 'of the inner heads I5 and it, these plates having openings through which the orifices 85 project into the annular spaces I9 and to in the heads I5 and I 6, and through which the shafts 7 project. These baflies intercept the oil that may splash out of the rotor slots 9 when the vanesdescend in the said slots and return most of it to the annular grooves 81 in the ends of the rotor, but some of the oil works outwardly along shafts l and lubricates the bearings at each end of the rotor, and some of the oil also drops the air before the air discharged from the compressor, notonly to eliminate oil'from the air delivered, but to recover as much of the oil as possible for reuse. To this end a pocket 9| is formed in the chamber 51, juxtaposed to the discharge orifice 56, so that the mixture of oil and air escaping from orifice 50 is directed 'into I the pocket 9|. In order for the air to escape from pocket 9| into chamber 5l it has to reverse its direction of flow and pass out between the rim of the pocket 9| and the edges of the orifice 56. As a result of this sharp change in the direction of the'fiow of the air within the pocket 9|,

down in the space between the inner head l5 and the outer head 5, and between the inner head I0 and the outer head 6, and flows through channels 88a in the lower edges of the heads i5 and it to the under sides of the floating rings 25. The floating rings have numerous pockets 2511 on their outer face and these pockets pick up oil received through channels 8811, asthe rings 25 rotate in service, thereby materially improving the lubrication of said rings.

When the pump is being operated as a compressor. the pressure adjacent the ends of the rotor is considerably above atmospheric, due to vunavoidable leakage past the ends of the rotor.

Such pressure would interferewith free gravi tational flow of oil from the reservoir 80 through the pipes 82. To equalize the pressure in the reservoir, I therefore provide an air tube 89 which communicates the space within the head 6 with the upper spaceof the reservoir 80. This insures equal pressures above and below the oil in the reservoir and uniform gravitational flow of oil from the reservoir through the conduits 85 into the compressor.-

Referring now to Fig. 3, it will be noted that the inlet port H is so positioned with respect to the rotor that excess oil escaping from the rotor slots accumulates in the bottom of the inlet port ii in the stator, creating a pool of oil therein. The lower edges of the ports 50, communicating the passage 5i with the port II,

are positioned a substantial distance above the bottom of the port II so as to permit a substantial pool of this oil to accumulate without overflowing into the intake passage 5I The bottom of the port I I preferably extends substantially horizontally and tangentially with respect to the lowermost portion of therotor. Therefore as the rotor rotates at high speed in a clockwise direction (the direction of rotation being taken with reference to Fig. 3), the outer edges of the vanes whip the oil in the pool in the ports I I' and splash it into the intake passage so that the oil is finely broken up and carried into and through the compressor with the air stream. This flow of oil through the compressor not only. helps to maintain proper lubrication between the moving parts but carries away dirt that might otherwise tend to accumulate within the pump. The mixture of air and oil is discharged from the pump proper through port I2, the lower inner edge of which is positioned well above the bottom ofthe port so spent oil and dirt can not flow back and foul the rotor. a

It is very desirable to separate the oil from walls to the bottom of the pocket where it es-' capes through a vent 92 into a sump 93 in the bottom of chamber 51. To reduce as much as possible the quantity of oil that tends to follow the air stream out of the pocket, the mouth of the pocket is preferably provided with an inturned flange 9a which traps excess oil and carries it to the bottom of thepocket and into the vent 92.

An oil return tube 95 extends from the bottom of the sump 93 up to an oil filter 95. Another tube 91 extends from the outlet of the oil filter to the top of the oil reservoir 80. Communication between the sump 93 and the tube 95 is regulated by a float valve 98 operated by a float. Whenever the oil rises in the sump above a pre- 90, whereupon oil is discharged from the sump through the filter 95 to the reservoir by virtue of the fact that the pressure existing in chamber 5'? and sump 93. is greater than the pressure in the oil reservoir. When the oil drops to a desired minimum level in the sump 93 the float valve 98 stops the flow or oil therefrom.

By virtue of the fact that when the pump is in operation the pressure within the ends of the compressor and theoil reservoir 80 is usually above atmospheric, 1 find it desirable to provide an automatic valve through which the reservoir 80 may be refilled as necessary without danger of the hole through which it is filled being accidentally left open, as such an accident would result in failure of the oiling system to operate. This valve comprises. a cylinder I00 formed within the reservoir 80' and in communi:

cation with the interior thereof through a vent I 0lin the lower end and a port I02 in the side. A piston I03 is slidably mounted in the cylinder I00, which piston is normally maintained in up-' permost position in which it blocks the port I02,

. by aspring I04 compressed between the piston and the lower end of the cylinder I00. The piston I03 is provided with a stem I 05 extending up through and beyond the .upper end of the cylinder. The upper end of the cylinder is normallyrclosed by a. screw cap I06 having a reentrant recess therein for clearing the valve stem I05. To replenish the oil supply in the reservoir, the cap I06 is removed, the stem I05 depressed to push the piston I03 clear of the port I02, and oil poured.in. The stem I05 is then released, and the filler cap I05 replaced.

whether or not the compressor was operating.

. and comprises a cylinder Obviously when the compressor is not operating there would be no pressure in the chamber 51 to restore the oil to the reservoir, with the result that the entire mechanism might become flooded with oil. I prevent possibility of such flooding by providing an automatic control valve interconnecting the reservoir 80 with the feed pipes 82. This valve construction is shown in Fig. 3, I01 formed in the wall of the reservoir 80, which cylinder communicates, adjacent its lower end, with the reservoir 80 through port H0, and, adjacent its upper end through a pipe I08, with the intake passage II of the compressor. The cylinder I01 contains a weighted piston valve I09, which, when in lowermost position, covers the ports leading to the pipes 82, but has its lower end positioned above the port leading to the reservoir 80. The piston valve I09 is connected by a stem H2 to a weight II3 for normally maintaining the valve in lowermost position. The upper end of the cylinder I01 is closed with a casing II l, which encloses the weight I I3 and seals the upper end of the cylinder from the atmosphere.

When the pump is not in operation, the pressure within the reservoir 80 is substantially atmospheric, Likewise, the pressure in the intake passage II is substantially atmospheric, Therefore, the pressures acting on the upper and lower surfaces, respectively, of the piston I09 are substantially equal, and the piston remains in its lowermost position by virtue of its weight. In this position, the ports in the cylinder I01 connected with the pipes 82 are closed, so that oil can not flow from the rservoir to the compressor.

However, when the pump is placed in operation, the pressure in the intake passage II is reduced, and the pressure in the reservoir is increased by virtue of the fact that certain leakage of air occurs past the rotor into the end spaces of the compressor, increasing the pressure in such spaces above atmospheric. This increased pressure in the end space within the compressor is transmitted through the air tube B9 to the reservoir 60. As a result of the decreased pressure acting on the upper end of the piston I09 and the increased pressure acting on the lower end, the piston is lifted to uncover the ports leading to the oil pipes 82, whereupon normal gravity circulation of oil from the reservoir to the compressor commences and continues as long as the compressor is working,

When the compressor stops, the pressures within the ends of the compressor casing and the inlet passage ll equalize, whereupon the piston I09 drops by its own weight to shut off the oil supply to the pipes 82. Test ports I I5 for attachment of pressure gauges may be provided at circumferentially spaced intervals in the upper half of the cylinder I, these ports being normally closed by screw plugs IIB.

Cylindrical recesses Ill and 8 may be provided in the passages 15 and 16 respectively, for the insertion of cylindrical wire screens to keep foreign matter in the air stream from reaching and fouling the valve cylinder 63.

A valve screw H9, adjustable into and out of the passage 15, is preferably provided to regulate the rate of flow of air to the upper end of the cylinder 03 and thereby regulate the speed at which the pistons 64 and 65 move.

For convenience, the invention has been explained by describing in detail one specific form understood, however, that many changes in the details of the particular structure shown can bemade without departing from the invention, which is to be limited only to the extent set forth in the appended claims.

I claim:

1. In a rotary machine of the type described, a horizontally disposed cylinder, a rotor eccentrically positioned off vertical center within the lower part of said cylinder and having radially slidable vanes therein, bearing means for rotatably supporting said rotor, said cylinder having inlet and outlet ports upon opposite sides thereof so positioned that fluid entering the cylinder hrough the intake port and discharged through the outlet port is compressed between the upper side of the rotor and the upper side of the cylinder, the plane of eccentricity of the rotor and stator extending at such an angle from the vertical and the vanes being so arranged that the vertical resultant of the fluid pressure forces on the rotor acts downwardly whereby the compressed fluid acts in the same general direction as gravity to aid gravity in holding the rotor down in the bearings.

2. In a rotary machine of the type described, a stationary casing member, a rotor eccentrically positioned within said casing member and having a radially slidable vane nearly contacting said casing member with its outer edge, means for rotatably supporting said rotor in said casing member, said casing member having a curved surface for nearly contacting and sealing with the rotor vane, which surface is shorter axially than said vaneand rotor, said surface merging into a counterbore portion of larger diameter at one end, an end casing member longitudinally slidable in said counterbore portion of said first mentioned casing member, for completing the compression chamber at the end of the rotor and vane, means for varying the longitudinal position of said end member in said counterbore to adjust the clearance between the end member and the rotor, and a removable filler ring interposed between said end member and the end of said counterbore, said filler ring effecting a seal between the end of said slidable end casing member and the end of said cylinder casing member, in which said means for varying the longitudinal position of said end member includes thermo-responsive pins bearing against and extending outwardly from the outer side of the slidable end casing member and anchored with respect to said casing member at their outer ends to compensate for expansion and contraction due to temperature changes and maintain a seal between said slidable end casing member and the end of said rotor in varying temperature conditions.

3. A rotary machine of the type described, comprising a stationary cylinder member, a rotor eccentrically positioned therein and having a plurality of radially slidable vanes adapted to nearly contact and seal with the inner surface of said cylindrical member, means for rotatably supporting said rotor in said cylinder member, the latter having a central interior surface shorter than said vanes and rotor and merging into a counterbored portion of larger diameter at each end, end casing members seating in said counterbored portions of said cylindrical member and completing the compression chamber at the ends of the rotor and vanes, said end casing members having inwardly extending flanges, th said of pump incorporating the invention. It is to be flanges having inner bearing surfaces thereon of larger diameter than the diameter of said interior surface of said cylindrical means, and a vane-retaining floating ring rotatably mounted within each of said flanges, the inner diameters of I said rings being slightly less than the diameter of the said interior surface of said cylinder member. 4. A machine as described in claim 3, with means for supplying oil to said floating rings, the

outer surfaces of the rings having circumferentially spaced recesses therein constituting oil pockets.

5. A rotary machine of the type described comprising casing means forming a rotor chamber having a continuous side wall, and end walls, at

ally supporting one end of said shaft while permitting rotational and longitudinal movement of the shaft relative to' the casing and bearing means for radially and longitudinally supporting the other end of the said shaft while permitting free rotation thereof, and means for adjustably supporting said last mentioned bearing means for longitudinaladjustment thereof relative to said casing, whereby said rotor can bepositioned with respect to said end walls by longitudinal adjustmentof said last mentioned bearing means and maintained in said position, said last mentioned bearing means comprising a cage threaded into said casing whereby said bearing can be adjusted longitudinally by rotating said cage, and means for fixing said cage in predetermined position of rotary adjustment.

6. In combination, a fluid pump having a fluid inlet passage and a fluid outlet passage, inlet valve means for closing said inlet passage in response to fluid pressure applied to said valve means, a check valve in said outlet passage for preventing return flow through said outlet pas-- a pressure equalizing conduit communicating the sage to said pump, and a pressure responsive means responsive to predetermined pressure in said outlet passage beyond the said check valve therein for applying fluid pressure to said inlet valve means and actuating the latter to close said inlet passage, said pressure-responsive means comprising a cylinder, a piston reciprocable therein and having a face exposed to pressure in said outlet passage beyond the said check valve, means yieldably resisting movement of said piston in response to pressure on said face, a duct from said cylinder to said outlet passage at a point ahead of said check valve, a vent duct in said cylinder, said piston normally blocking said cyl-- inder between said ducts but moving out of blocking position in response to said predetermined pressure.

-said vane and the-outer portion of the end of said rotor, a shaft for rotatably supporting said rotor extending therefrom and through an aperture larger than said shaft provided therefor in said inner end wall, an outer end wall sealing and within said aperture in said inner wall, and

space between said inner and outer end walls with the upper portion of said oil reservoir, whereby oil flows by gravity from said reservoir through said oil feeding conduit to the rotor ends irrespective of the pressure between said end walls and rotorr 8. A machine as described in claim '7, in which theopen end of said oil conduit adjacent to the -rotor end is directed in the direction of rotation of said rotor, whereby windage created by the rotor tends to draw oil from the conduit.

9. A machine as described in claim 7, in which said rotor is provided with an annular recess in the end thereof below the end of said vane slot whereby oil from said conduit is directed below the vane into the vane slot in the rotor.

10. A machine of the type described comprisinga cylinder, a rotor therein having a radial slot with a vane slidably mounted in said slot, said vane nearly sealing with the cylinder, an end'wall sealing with one end of said vane and with the outer portion of the one end of said rotor, a shaft rotatably supporting said rotor extending therefrom and through an aperture larger than said shaft provided for the passage of the shaft in said end wall, means for supporting said shaft, anoil reservoir, an oil feeding conduit extending from said reservoir to a position adjacent the end of said rotor within said aperture in said wall, the outer orifice of said aperture being smaller than the inner orifice thereof, whereby the end of the rotor and the aperture wall form an annular trough for containing 011., e

11. A machine of the type described, comprising a casingmeans forming an inlet passage and an outlet passage, and a mechanism therebetween which creates when in operation a higher pressure within said mechanism than iii the inlet passage, a closed oil reservoir above said mechanism, an oil conduit extending from said reservoir to a point within said mechanism for delivering oil thereto by gravity flow to lubricate the same, a pressure equalizing conduit communicating said reservoir with the interior of said mechanism, and pressure responsive valve means v for communicating said oil-conduit with said reservoir only in response to pressure in said reservoir higher than the pressure in said inlet passage, in which said 011 reservoir has a flller opening for replenishing the oil supply therein,

fluid inlet passage and a fluid outlet passage, in-

with said cylinder and about said shaft, a closed 7 oil reservoir above said cylinder, an oil feeding conduit extending from the lower portion. of said reservoir to a point adjacent the end of said rotor 76 ahead of said check valve,

let valve means for closing said inlet passage in response to fluid pressure applied to said valve means, a check valve insaid outlet passage for preventing return flow through said outlet passage to said pump, 'a pressure responsive means responsive to predetermined pressure in said outlet passage beyond the said check valve therein for applying fluid. pressure to said inlet valve means and actuating the latter to close said inlet passage, said pressure-responsive means comprising a cylinder, apiston reciprocable therein and having a face exposed to pressure in said outlet passage beyond the said check valve, means yieldably resisting movement of said piston in response to pressure on said face, a duct from said cylinder to said outlet passage at a point a vent duct in laid having a weight thereon, said weight being positioned upwardly and outwardly from the fulcrum point of said lever, whereby the force applied to said piston by said lever arm is greater when said piston element is in said first position than when in said second position, and a substantially higher pressure in said outlet passage is required to move said piston from said first to said second position than to retain the piston in the second 10 position.

JOHN C. BUCKBEE.

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