US2082412A

US2082412A - Rotary compressor

Info

Publication number: US2082412A
Application number: US627442A
Authority: US
Inventors: Harry E Morton
Original assignee: BF Sturtevant Co
Current assignee: BF Sturtevant Co
Priority date: 1932-08-04
Filing date: 1932-08-04
Publication date: 1937-06-01
Anticipated expiration: 1954-06-01

Description

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' ROTARY COMPRESSOR Filed Aug. 4, 1.932 v e sheets-sheet s v Patented June l, 1937 UNITED sTATEs l 2,082,412 ROTARY COBIPRESSOR llarry E. Morton, Hyde Park, Mass., assignor to B. F. Sturtevant Company, Hyde Park, Mass., a corporation of Massachusetts Application August 4, 1932, serial No. 621,442

4 Claims.

The present invention relates to rotary compressors and more'particularly to that type of vcompressor which comprises a pair of intermeshing spiral gears and whereinv a uid is employed for sealing and lubricating the same. Y r

It is the object of the present invention to provide a rotary compressor of the above type which shall be of simple and sturdy construction, inexpensive to build. and elcient and long lived in operation.

With these objects in view the present invention consists of the devices and combinations of devices hereinafter described and moreY particu' larly dened in the claims.

In thefaccompanying drawings-in which is illustrated what is now considered the preferred form of the present invention, Fig. 1 is a front elevation of a compressor embodying the invention, viewed on the inlet side with the strainer removed; Fig. 2 is a vertical longitudinal section on line 2 2 of Fig. 4;.Fig. 3 is a horizontal longitudinal section on line 3-3 of Fig. 5; Fig. 4 is an end elevation, looking from the left of Fig. 1, showing the compressor with the inlet strainer attached; Fig. 5 is a vertical transverse section on line 5-5 of Fig. 1 looking toward the right; Fig. 6 shown in perspective, with certain parts in section, the main casing or housing of the compressor; and Fig. 7 shows one of the -heads or end assemblies for such housing.

The compressor illustrated in the drawings comprises a main casting or housing within which rotate a pair of intermeshing double spiral or herringbone gears.

is admitted to the interior of the housing on one side of the housing and is delivered tothe faces of both gears in a zone adjacent the line of intermesh and extending the length of the gears. The

, compressed gas is discharged from the gears through a relatively short zone adjacent the point of intermesh of the apices of the gears and thence through the outlet of the housing.

The rotating gears are lubricated and sealed against leakage of gas by means of alubricating and sealing liquid which passes through the bearings and thence into the interior of the housing..

A water-jacket is provided for the housing to absorb the heat generated by the compression oi' 'the gases. l

'Considering now the illustrated construction of the rotary compressor in more detail, the housing III, as shown in Fig.. 6, is of cast construction having two parallel cylindrical bores I2 and Il which slightly overlap or intersect. Each end of the housing is provided with the attaching face or The gas to be compressed `iiange I6 and aroundy the housing extends the water-jacket I8 with the 4top openings or connections 20. On one face of the housing termed the iront, midway the ends is the boss 22 with the gas inlet passage 24 and attaching face 26. 'I'his 6. inlet passage opens into an inlet chamber^28 extending nearly the entire length of the interior of the housing and for about one-quarter of the circumference of each gear from its line of intersection.' See Figs. 3 andV 5.

The opposite face of the housing is provided with a similar boss 30 through which extends the gas outlet passage 32 and to which is clamped the fitting 34, in turn threaded to receive the outlet pipe 36. See Fig. 5. 15

The margin of the angular partition between the bores I2 yand I4 adjacent the outlet passage is cut away, as shown in', Figs. 5 and 6, to form the outlet chamber 38 which extends a short distance on each side of the line of the apices of the gears. 20

The open ends of the housing are closed by the heads or assemblies shown in Fig. 7, one at each end. Each assembly comprises the ellipticaliyshaped head 40 -with water-jacket 4I andA with the face or flange 42 to engage and be secured to the 25 cooperating ange I6 on the housing by means of the tap bolts 44. Each of the heads is provided with the two cylindricalbores I6, one above the other, within which are mounted the ball-bearings 48 .Ior'the 30 gear shafts. At the inner-.end of each bore is secured the ang'ed sleeve 50 comprising a sleeve portion 52 tting snugly within the bore 46 and holding theball-bearing from inward movement, and the flange or head' 5I overlying the inner face 35 42 of the head and tting within one of the cylindrical bores I2, Il, of the main housing I0.. Screws 56 passthrough the flange or head 5I to secure the sleeve iixedly to the head 4Il. At the bottom of the top lange and the top of the bottom 40 flange a segment is eut away, as shownlat 58.,

'to permit vthe parts to beassembled.-

These heads or flanges 64 serve not only as thrustor wear-members for the ends of the gears, but lalso to position the heads 40 accurately on 45 the housing III so thatthe'ball-bearing will be exactly centered with their corresponding bores in the casing, thus permitting the gears to operate with a uniform minimum clearance between their teeth and the walls of the bores, a condition 50 which is necessary to elcient operation and the securing of high pressures. Inasmuch as the described parts -are positioned with respect to one another by means of cylindrical 'contacting surfaces, which may be easily and ycheaply ma- 55 chined, the desired accuracy of t and high eiciency. of operation may be secured with a minimum cost of manufacture.

The ball-bearings are held from outward movement by the closures for the outer ends of the bores 48 of the heads 40. Referring to the head for the left end of the apparatus as viewed in Figs. 2 and 3, the closure' for the lower bore consists of the circular plate or head 60, having a cylindrical portion or sleeve 82 entering the outer end of the bore 46, and an overlying flange or head 64 secured to the head 40 by means of the bolts 56.

The closure for the top bore includes a stumngbox surrounded by a water-jacket to prevent unduly high temperature. This closure comprises the main casting 68 having the sleeve portion 10 tted within the outer end of the upper bore I2, provided with a water-jacket'12. and is secured to the head 40 by means of the bolts 14. The

casting 68 is counter-bored in the usual manner to receive the packing 18 which is compressed by the follower 18 by means of the bolts 80.

The water-jacket 121s arranged in parallel with the water-jacket 4| in the head, being connected with the bottom of such water-jacket by means of the fittings comprising the elbow 82, vertical pipe 84, and flanged fitting 86. A right angled fitting 88 connects the top. of the water-jacket 'l2 with the top of the water-jacket 4| in the head 40. The water-jacket in the head 40 is in turn connected with the water-jacket |8 in the main housing by means of the return bend 80. Water is supplied to the lower portion of the waterjacket 4| of the head 40 through the inlet connection 92.

The head at the opposite end of the housing, namely. the right-hand end, as viewed from the front as in Figs. 2 and 3, is identical with the head at the left-hand end except that inasmuch as there is no projecting shaft which requires a stuffing-box, the closures for the two bores are identical 'and like that of the lower bore on the left-hand head. The right-hand head is also provided with a similar water-jacket 94, connected to the water-jacket of the housing by the return bend 88. land having the 90 bottom outlet connection 88.

The gears |02 and |04, within the bores of the housing are of the double herringbone design commonly employed in this type of apparatus. The upper gear, f|02, is driven in a suitable manner through its projecting shaft |06, and is provided at its opposite end with the stub shaft |08,

both shafts being mounted in the ball-bearing 48, the inner members 0 of which are each secured between a collar ||2 ancha washer ||4 and nut ||8 on the threaded sections of the shaft.

The lower or idler gear |04 has stub shafts ||8 at. each end, similarlymounted in the ball-bearings, with similar collars, washers, 'and nuts. As is the practice with this type of apparatus, the gears are sealed and made gas tight by means of a liquid whfch is supplied to them in' screwed into the boss |22 on the front of the housing and connects through the short transverse passage |24, with the longitudinal passage |26 extending the length of the front wall of grooved into two diverging oil grooves or passages |28. see Fig. 7. When the head is in place, the

open face-of these grooves at their outer ends is closed by the end of the housing, and at the inner ends by the flanges 54 of the hanged sleeves 50.

Each oil groove connects at its inner ends with a hole |30 in the head 40, (see Fig. 3,) which is provided at the outer end with the screw-threaded valve-seat |32.

In the end closure for the bore in the heads 40 (see Fig. 3, right-hand end) are the openings or passages |84 which communicate through the curved branch |36 with the bore 48 wherein are located the ball-bearings to supply the latter with the lubricating and sealing fluid. The rate of flow is regulated by means of a valve comprising a conical valve face |38 having a square outer end |40 to receive a wrench or handle, the valve being mounted in the plug |42 screwed into the outer end of the passage |84 and provided with a stumng-box and follower |44 to prevent leakage.

A similar construction is provided for the closure 08, the valve stem |48 being much longer of necessity by reason of the greater axial thickness of the closure. (See Fig. 3, left-hand end.)

The lubricating fluid passes through and around the ball-bearing and thence through the longitudinal passage |48 to the open groove |50, (see Figs. 3, 5 and 7,) in the inner faces of the flanged sleeves 50. The outer ends of @these grooves are positioned slightly beyond the bottoms of the gear teeth (see Fig. 5) so that the lubricating and sealing fluid will be delivered not only to the end faces of the gears to lubricate the same, but also into the spaces between the teeth to both lubricate and seal.

The rotation of the gears is such with respect to the inclination ofthe teeth that the lubricant tends to work inwardly along the teeth'toward the middle or apices, at the same time being distributed by the rotation of the gears over the internal surfaces of the main bores |2 and I4.

The lubricating or sealing fluid thrown o by the engagement of the spices of the gears is carried by the compressed gas through the outlet 82 and thence to the usual separator where itis 'separated from the gas and then returned to the system.

While the compressor herein shown and described may be used for compressing air, it is designed primarily for use in the compression of a refrigerating gas. and for such purpose will be provided with suitable supply connections including a filter or screen to filter out and remove from the gas supply Iany solid particles of dirt, scale, or other material which would cause damage or excessive wear to the apparatus. Such a filter is shown in Figs. 4 and 5,. and comprises a main casting |52, having a bolting flange |54 for attachment to the boss 22 of the compressor housing. The gas supply pipev |58 isconnected .the top and bottom of the illter are covered by the covering plates |82. and the interior is provided with a cylindrical screen |84 through which the gas passes from the lower chamber |88 to the 4 upper chamber |68.

In the operation of the rotary compressor by means of a anged fitting |58 bolted to the Y face of the filter casting. The openings at herein shown and described power is applied to the shaft extension |06 to drive the gear |02 which in turn drives the gear |04. As the gears pass the inlet chamber 28\the spaces between their teeth are iilled with gas which is carried cessive temperatures in either the apparatus or the compressed gas.

The lubricating and sealing uid is delivered from a single source through the several connections in nicely regulated amount, first to the bearing, then to the ends of the gears, and finala ly to the teeth themselves where they lubricate ter.

and at the same time act to seal the apparatus and prevent leakage in operation.

The above described compressor, it will be noted, is of simple, compact, and rugged con- Y struction, with close and exact fitting of the `parts secured by inexpensive machine operations almost entirely of a turning and boring charac- Owing to the method of construction and of fitting the parts, the `apparatus may be quickly dismantled for the purpose of examination or replacement, and as quickly reassembled with certainty of proper and exact fitting of the parts.

While the present invention has been shown and described as embodying a particular form of apparatus, it is to be understood that the invention is not necessarily limited thereto, butmay be embodied in other forms and constructions within the language of the following claims.

Having thus described the invention, what is ciamed is:

l. A rotary compressor comprising a housing having a pair of cylindrical bores, a pair of intermeshing herringbone gears mounted to rotate within the `housing in said cylindrical bores, shafts for the gears, one of` said shafts being provided with a drivingextension, ahead for closing the end of 4the housing and having openings of uniform diameter therethrough adapted to be axially aligned with the bores of the housing, bearings for the shafts in said openings, clo- 1 sures for the inner and the outer ends of said openings, the inner end closures extending into the bores to center the heads and one of said outer end closures being provided with a stufngbox with packing therein for the driving extension of the gear shaft and with a water-jacket surrounding the packing in the stumng-box, and means for securing the head to the housing.

2. A rotary compressor comprising a housing having a pair of cylindrical bores, rotary members in the bores provided with intermeshing teeth, a

detachable head for the housing, cylindrical openings in the headof less diameter than the bores of the housing and adapted to be aligned coaxially therewith, bearingsin the openings in the head, and flanged members having a portion of small diameter adapted to fit closely within an opening in the head between the bearings and the bores of the housing, and a portion co-axial with the said first mentioned portion and of larger diameter and adapted to t closely within a bore of the housing and forming end bearingsA for the rotary members, the housing being provided .with a lubricating fluid passage terminating on the end attaching face of the housing and the lhead being provided with an open groove on its the bearings to the ends of the rotating members and the teeth thereof.

3. A rotary compressor comprising a housing having a pair of cylindrical bores, intermeshing herringbone gears withinthe bores, one of said gears being provided with-a shaft extending therefrom, a detachable head for the housing. cylindrical openings in the head of less diameter .than the bores of the housing and adapted to be aligned co-axially therewith, flanged members having a portion of smaller diameter adapted to fit closely within the openings in the head and a portion co-axially with said first mentioned portion and of larger diameter and adapted to fit closely within a'bore of the housing and form end bearings for the rotary members, bearings within the openings in the head, and a combined closure and stumng-box for closing the outer end' of one of the openings and surrounding the shaft, the combined closure and stuiiing-box being provided with a cylindrical inner portion tot closely within the outer end of the opening in the head to center -the stuffing-box.

4. A rotary compressor comprising a housing having a pair of parallel cylindrical bores, a pair of inter-meshing gears in said bores .having shafts, a detachable head for closing each end of the housing and provided each with a pair of a cylindrical openings adapted t'o be aligned coaxially with the bores of the housing, means for removably fastening said heads to the respective f ends of the housing, centering members each having a portion closely fitting within one of said openings in the head and another portion coaxial withthe first mentioned portion and closely fitting Within the adjacent bore of the housing, each centering member having a central hole through which a shaft extends, means for rigidly fastening these centering members to the respective faces of the heads, so that when the heads` are fastened to the ends of the housing the bores of the head will be axially aligned with the bores oi' the housing, an anti-friction ball-bearing assembly located in each one of the bores of the head, its inner race-way being.' adiustably mounted on the adjacent shaft and its outer race-way being fitted to the interior of the bore, the inner end of the outer race-way being in abutting relation with that portion of the centering member fitted into the bore and removable cover- HARRY E. MORTON.

' means for the outer ends of the two bores of each