US1952142A - Compressor - Google Patents

Description

March 27, .1934. F, PETERSON 1,952,142

v COMPRESSOR Filed June 8, 1951 4 Sheets-Sheet 1 J m l E:

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gwumlw March 27, 1934. v F, c PETERSON 1,952,142

COMPRESSOR Filed June 8, 19551 4 Sheets-Sheet 2 :1 Emnczs CPelemon March 27, 1934.

F. C. PETERSON COMPRESSOR 4 Sheets-Sheet 4 Filed June 8; 1931 E'QRCBCPQQJOR Patented 27, 193 4 UN -TED STATES PATENT OFFICE Myyinvention relates to an improvement in rotary devices intended for uselas a compressor,

or as a pump, and the principles of which are also capable of embodiment, as is recognized in 5 the art, in a motor or clutch.

The present invention is more espe ially an improvement upon such' devices as are shown in my prior Patents, Nos. 1,645,069 an 1,683,143. In the construction of'compressors of is type, which embody a cylindrical rotor, eccentrically placed within a-cylindrical casing, it has not been found feasible to employ solid ends to close in the space between the rotor and casing, through which space vanes; projectible from the rotor and retractible thereinto, sweep, but it has been found difficult to position rings or plates to close the ends of this space, in such manner as to prevent leakage without undue pressure on the ends, One of the objects of. my invention,then

tures, wherein the ends of this space are closed by adjustable rings, whereby the pressure may be maintained at all times just sufficient to cause a wiping contact, and to prevent leakage, even under high pressure, yet such as will not. cause undue friction.

In devices oi. this type, employing vanes pro jectiblefrom and retractible into the rotor, great diiflculty has always been encountered in the drag of the vanesupon the casing caused, first, by an attempt to maintain a tight joint between the two, and second, by the centrifugal action on the vanes, tending to throw them out. To a considerable extent this has been overcome by the provision of rollers attached to the vanes, and riding upon tracks which are so designed as to maintain the vanes always in wiping contact with the casing, but because of the segmental shape of the vanes which I prefer, it has been found difllcult heretofore to maintain the wiping contactthroughout the 360 of rotation of the rotor by the use of a track for the rollers which could be cheaply" and easily manufactured and assembled. The geometrical design required by the assembly formerly employed has departed from a-true circle, and hence has been diflicult to manufacture with exactness. Accordingly, it is an object of the present inventioirto provide a track and so to design the parts relative. to each other that all may be made up on a circular pattern, thus greatly simplifying manufacturing processes, increasing accuracy and, consequently, efficiency in operation, and making almost impossible the improper or imperfect assembling of the device.

is to provide a construction embodying these fea- Generally speaking, then, it is an object of the present invention to provide a compressor of the same general type as that shown inmy previous patents, yet to simplify this in its construction, adjustment, manufacture and assembly, and with all of this, to increase its efliciency.

It is also an object of prime importance to devise a lubricating system for such a device which will assist in sealing partsagainst leakage, and which will automatically insure an adequate supply of lubricant to all parts of the compressor. Q

My invention comprises the novel parts, and the novel combination and arrangement thereof, as shown in the accompanying drawings, de- '70 scribed in this specification and as will be more particularly pointed out by the claims which terminate the, same. A

In the accompanying drawings, I have shown my invention embodied in a typical compressor,

of a type as now preferred by me, it being understood that various changes may be made therein within the'scope of the invention as described in this specification, and as defined in the claims.

Figure 1 is a side elevation of such a compressor."

Figure 2 is an Figure 3 is a transver axial section therethrough.

section orfiline 3-3 of Figure 2, and Figure 4 s a similar section on line 4-4 of Figure 2 a Figure 5 is an elevation, with parts broken away, of a typical refrigeration system, with .which such a compressor is peculiarly adapted for use, and the lubrication system.

' My invention consists in' general of the cylindrical casing 3 open at its endsand closed by the cover plates 30and 31, the cylindrical rotor 1 upon the drive shaft 10, the axis R of which is .offset from the axis E of the casing, and a plurality of segmental vanes 2 projecting through slots 12 in the rotor and carried upon the outer end of arms 21, which are pivotally mounted at 20 within the rotor. The points 20 are the centers of the respective segmental vanes2. The arms 21 move in chambers 11 of the rotor, so that the contact and a suitable bearing block maybe located at this-point.

The space between the rotor and casing is in the construction so far described, open at the ends, and it is necessary that this be closed to retain compression. As has been pointed out,

' it is undesirable to close this by a fixed wall or be axially adjustable, and to this end a threaded engagement between the two is provided, as indicated at 43, thereby providing for uniform bearing upon the rotor throughout their entire circumference. It is important that means be provided for preventing the rings from being turned up 'more tightly by the frictional engagement with them of the rotor. In the machine illustrated, any such tightening of the rings is prevented by so cutting the threads that the ring will be moved away from the rotor by any turning movement due to friction which would be instantly relieved. To enable adjustment to be made while the compressor is operating, that is, under service conditions, each of the rings 4 is provided with geared teeth 40, and with each of these gears is engaged a pinion 41, which is mounted upon a shaft 42, upon which,'outside of the casing, is secured a non-circular head 44, by means of which the shaft and its pinion may be rotated to cause rotation of the corresponding ring 4 and its consequent axial adjustment by reason of the threads at 43. The lubricating arrangement, later described, insures against leakage, yet prevents wear with parts properly adjusted. I

To take the outward thrust of the vanes 2 and to prevent excess friction between the outer ends of the vanes and the casing, I provide circular tracks 5, which, for convenience of manufacture, may be made as part of the end plates and 31 respectively. Riding upon these tracks are rollers 25, which are secured upon the ends of the vanes 2, at the junction between their inner ends and their supporting arms 21. At this point, the vanes are provided with trunnions 22, which project axially of the compressorand which maycarry anti-friction bearings 23 between the trunnions and the rollers 25. The trunnions extend through the end rings 4, thereby enabling the tracks 5 to be placed outside of the end rings.

The tracks 5 are so located with respect 'to the vanes and the rollers 25, that the rollers rolling about this circular track will maintain the outer end 26 of the corresponding'yane 2 always in wiping contact with the inside of the cylindrical casing 3, yet will never permit undue pressure, and consequent wear thereon, but will take all of the radial thrust associated with its vane.

Floating rings 2'7, surrounding the shaft at each end of the rotor, are engaged by all the rollers 25, to prevent them from losing contact with the tracks 5, when the device is stationary, for instance. These floating rings likewise assist in the distribution and control of lubricant, as will appear hereafter.

By reason of the segmental form of tne vanes 2, and their oscillation about centers 20, it is necessary, in order that the centrifugal force be borne by the track 5,-the vanes, however,

being maintained in wiping contact with the outer wall of the casing,that the track be slightly eccentric to the casing. The correct'location of its center may be determined mathematically or by the use of suitable drafting instruments.

While the elimination of friction, both from the side bearings and from the contact of the vane with the casing, is of primary importance in prolonging the life of thecompressor and its efficiency, it is important also as enabling proper lubrication of the device, and this lubrication is also responsible for greatly prolonging the efliciency and serviceability 'of the compressor. Such lubricating system as I prefer to employ, is best illustrated in Figure 5.

In this figure the casing 3 is shown as mounted upon a large tank or holder 6, in which is received liquid ammonia, or other refrigerant, andinto which the compressor discharges. Either incorporated in the bottom of this holder, or therebelow, is a second holder 60, in free communication with the main holder 6. Since lubricating oil is heavier than the liquid ammonia, the oil will collect at the bottom of the liquid system, and since the two holders, 6 and 60, are'in free communication the oil will be under precisely the same pressure as is the liquid ammonia. There is considerable difference of pressure between the pressure side 13 and the suction side 14. This difference of pressure may be utilized to draw oil through a pipe 61 from the oil sump or holder to discharge through the end plate 30, adjacent the main bearings for the shaft 10, whence it may travel through the shaft or into the central space within the end rings 4. This part of the compressor is kept flooded with oil, and since its pressure is reduced by friction in moving through the pipe 61, its pressure in the pump is slightly 4 the vaporous refrigerant into the holder 60. i

There it sinks to the bottom and separates, while the heavy vaporous refrigerant is transformed into the liquid state by cold water running through the ducts 62 within the holder 6. This lubricating process is repeated over and over, the interior of the compressor, except the compression chambers, being-kept flooded with lubricant, which gradually seeps out, and which, because it is under pressure approximately that of the compression side of the compressor, does not permit leakage of pressure outwardly, that is, between the rotor and the end rings 4, yet all parts of the compressor are thoroughly lubricated.

For clearness of understanding, it may be noted in Figure 5 that a motor '7 is provided to drive the compressor, by means of a belt 70, and various switches and gauges are indicated at 8. At 63 is the discharge pipe for the liquid refrigerant on its way to the pressure reducing valve and the refrigerating coils (no-t shown), while 64 indicates the return pipe to the suction side 14 of the compressor.

What Iclaim as my invention is:

1. In a rotary compressor, in combination, a cylindrical casing having a smooth irmer circumferential surface and an annular axially adjustable side wall, an eccentric rotor within the casing and engagingv the side walls thereof and having peripheral pockets, segmental. vanes housed within the pockets and projectable therefrom and being pivoted to the rotor at their centers. of curvature, and means for sustaining the centrifugal force acting on the vanes and maintaining them'in continuous wiping contact (with the circumferential wall of the casing, such means comprising an inwardly facing track outside of the adjustable side wall and rollers carried by the vanes and engageable with the track.

2. In a rotary compressor, a cylindrical casing having a circular inner periphery, annular side walls' forming a pump chamber with the inner wall of the casing, a circular track positioned exteriorly of one of the side walls and eccentric to the periphery of the pump chamber, a rotor mounted in the casing eccentric to both the track and the pump chamber periphery, vanes pivotally mounted on the rotor adapted to maintain a wiping contact with the periphery of the pump chamber, and rollers carried by the vanes and riding on the track, said track being disposed so that it sustains the centrifugal forceacting onv the vanes but permits continuous wiping contact of the vanes with the peripheral wall of the ,7

' positioned exteriorly of one of the side walls and casing,

3. In a rotary compressor, a cylindrical casing having a circular inner periphery, annular side walls forming a pump chamber with the inner wall of the casing, one of the side walls being in threaded engagement with the casing for axial adjustment relative thereto, a circular track. positioned exteriorly of one of the side walls and eccentric to the periphery of the pump chamber,

a rotor mounted in the. casing eccentric to both the track and the pump chamber periphery, vanes pivotally mounted on the rotor adapted to maintain a wiping contact with the periphery of the pump chamber, and rollers carried by the vanes and riding on the track, said track being disposed so that it sustains the centrifugal force acting on the vanes but permits continuous wiping contact of the vanes with the peripheral wall of the casing.

4. In a rotary,compressor, a cylindrical casing having a circular inner periphery, annular side walls forming a pump chamber with the inner wall of the casing, one of the side walls being in threaded engagement with the casing for axial adjustment relative thereto, gear teeth'on the wall, a pinion meshing with the teeth for rotating the wall and effecting the adjustment, a circular track positioned exteriorly of one of the side walls andveccentric to the periphery of the pump chamber, a rotor mounted in the casing eccentric to both the track and the pump chamber periphery, vanes pivotally mounted on the rotor adapted to maintain a wiping contact with the periphery of the pump chamber, and rollers carried by the vanes and riding on the track, said track being disposed so that it sustainsthe centrifugal force acting on the vanes but permits continuous wiping contact of the vanes with the peripheral wall of the casing.

5. In a rotary compressor, a cylindrical casing having a circular inner periphery, annular side walls forming a pump chamber with the inner wall of the casing, a circular track positioned exteriorly of one of the side walls and eccentric.

to the periphery of the pump chamber, a rotor eccentrically mounted in the casing with its periphery projecting into the pump chamber, said .rotor comprising a solid cylindrical body provided with a plurality of pockets opening through slots to the exterior, vanes reciprocable in the slots for maintaining a wiping contact with the periphery of the pump chamber, a circular track eccentric to the periphery of the pump chamber, rollers carried by the vanes and riding on the track, said track being disposed so that it sustains the centrifugal force acting on the vanes but permits continuous wiping contact of the vanes with the peripheral wall-*of the casing.

6. In a rotary compressor, a cylindrical casing having a circular inner periphery, annular side walls forming a pump chamber with the inner wallof the casing, a circular track positioned exteriorly of one of the side walls and. eccentric to the periphery of the pump chamber,

'a rotor mounted in the casingeccentric to both the track and the pump chamber periphery, vanes pivotally mounted on the rotor adapted to maintaina wiping contactwith the periphery speeds I a a v FRANCIS C; PETERSON.

'of the pump chamber, rollers carried by the

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