US2233168A - Compressor - Google Patents

Description

COMPRESSOR Filed April 19," 1939 Fig.2.

y Invent-Job Wilfrid. E.J ohnson,

Attorney.-

Patented Feb. 25, 1941 comnnsson Wilfrid a. Johnson, Fort Wayne, ma, assignor to General Electric. Company, a corporation oi! New York Application April 19, 1939, Serial No. 268,736

14 Claims.

,- My invention relates to fluid compressorsand the like and more particularly to fluid compressors employing a splash teed lubricating system.

It is an object oi my invention to provide 'a new and improved compressor construction which is rugged in construction and efllcient in operation.

Compressors designed to operate at high speeds and to use a splash ieed lubrication system enm counter conditions under which it is difllcult to provide for the return of lubricating oil to the crankcase oi the compressor after it has once passed the pistons. Because 01' the extremely vigorous splash occurring in the crankcase there is a tendency to throw oil out or the" crankcase and prevent its return from the inlet or suction side of the compressor. This difliculty is intensifled in the event oi even a small leakage oi the working fluid past the pistons into the crankcase.

Whenever this fluid leakage occurs the leakage fluid will flow out from the crankcase into the suction line through any oriflce or passage that is provided tor the purpose or returning lubricant 25 from the suction line to the crankcase and carry entrained lubricant therewith. Hence, it is a further object of my invention to minimize the accumulation of lubricant in the external part of the refrigerant system including the conden- 30 ser, evaporator and liquid receiver, for example,

by returning to the crankcase any excess lubricant accumulating in the external part oi the refrigerant circuit.

It is also an object of my invention to provide 5 means for returning any 01' the working fluid which has leaked past the piston into the crankcase to the suction side of the system without hindering the return of lubricant t0 the crankcase.

40 Further objects and advantages of my inven-' tionwill become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to 45 and forming a part of this specification; c

For a better understanding or my invention reference may be had to the accompanying drawing in which Fig. 1 is a schematic diagram illus trating the operation 01 apparatus embodying 50 my invention; Fig. 2 is a side elevational view,

partly in section, illustrating s compressor embodying the principles of my invention and Fig. 3 is an end view. partly broken away, oi. the compressorshowninFig. 2.

s5 As shown in Fig. 1, I have provided a com- (Cl. sac-.187

pressor I! having a crankcase ii, an exhaust line I! and an inlet or suction line I3. 011 separating chamb rs u and is are also provided. a I conduit it communicates between crankcase ii and the separating chamber it above the lubricant levels therein and I provide a second conduit l1 communicating between separating chanibers II and i5 above the lubricant levels therein. In the suction line it there is provided a pressure reducing means I s, such as a ,Venturl contracts. A conduit I8 communicates between the low pressure region of the pressure reducing means is and the upper portion of lubricant separating chamber it above the lubricant level therein; The inlet conduit is terminates in an inlet chamber or manifold M, a restricted passage 2i being provided between the inlet chamber .20 and the crankcase Ii for returning any lubricant deposited in the inlet chamber 20. The restriction in passage 2! should have a smaller cross-sectional area thanany portion of the path 01' flow throughchambers it and it and passages, I] and i. 1 Separating chambers l4 and "have a connecting passage or conduit 22 below the lubricant 25 level in the chambers I4 and i5 and the lower portion of chamber ii is connected to the crankcase I l below the lubricant level therein by means 0! alubricant return conduit 23.

The operation of the systemis as follows: Because of the presence of passage 21, working fluid as well as lubricant may pass from the inlet chamber 20 to'the crankcase ii. The flow of gas through the venturi it in the suction line 3 It causes a reduction of pressure at the throat I of the venturi it which tends to siphon the working fluid from the crankcase ii through the passages it; I! and i8 and chambers I4 and i! into the throat oi the venturi ii and the suction line it. Consequently. there is a constant circula- 40 tionoi working fluid through the abo've dmcnibcd circuit during normal operation of thesystem. It suiilcient injector capacity is provided at the venturi and if the passages it, ii and it are sumciently large and the leakage past the is not excessive, there will be a reduction or pressure in the crankcase below that existing inthe suction manifold Iii. Note that the pressure in thesuction manifold 20 will be equal to that in thesuction line at the mouth of the venturi ll "except for due to friction and to the injector. loss. Because the pressure is higher in the inlet chamberthan in the crankcase, any oil deposited in the inlet chamber will be returned to the-crankcase through the restricted passage direction of flow in chamber I4 and the reduced velocity of flow caused by the sudden increase in 4 volume of chamber I4 compared to conduit I6,

the lubricant is to a large extent separated from the fluid and falls to the bottom of the chamber I4. Because of the flow of lubricant and fluid from the crankcase into the chamber I4, there will exist a pressure drop and the. pressure in the chamber- I4 will be lower than that in the crankcase resulting in the lubricant level being higher than the lubricant level in the crankcase as illustrated. Because of the action of the lubricant separator I4, there will be mainly a flow of gas without lubricant through conduit I'I into the separator chamber I5 but any oil that is still entrained is separated in the chamber I5. Again,

due to the pressure drop between chambers I4 and I5, there will be a higher lubricant level in chamber I5 than in chamber I4 as indicated in the drawing. Whenever the amount of lubricant collecting within the chambers I4 and I5 is sufficient to overcome the pressure in the crankcase II, any excess lubricant will be returned to. the crankcase by way of conduit 23. While the schematic arrangement illustrated in Fig. 1 illustrates a systemusing two separating chambers in series, one or more separators may be used depending upon the degree of separation re-' quired. I

'Describing my invention in greater detail and referring to Figs. 2 and 3, I'have illustrated a compressor embodying the features of my invention. Primed numerals will be used in Figs. 2 and 3 to indicate corresponding partsof Fig. 1. A compressor I0 having a plurality of cylinders radially arranged is illustrated having a cylinder block 24 provided with cylinders 25 adapted to receive a movable element for displacing the working fluid as, forexample, reciprocable pistons 23. In order to reciprocate the pistons 28 within the cylinders 25, I have provided a shaft 2? suitably secured to an eccentric comprising crank arms 23 and crank pin 29, and 8. connecting rod 38. The shaft 21 is arranged to rotate in a bearing 3! suitably supported in the hub 32 of the end plate 33. The shaft 21 may be driven directly by a motor, not shown, or if desired a pulley, not shown, may be secured to the shaft 27 whereby the compressor may be belt-driven. The lubricant level within the crankcase I I of the compressor ill is indicated by the dotted line. As shown in Fig. 2, the counterweight portions of the crank arms 23 are-arranged to dip into thelubricant in order to'provide a splash feed lubrication system.

" The inlet chamber orsuction manifold 20' is illustrated as generally annular in shape and the'inlet chamber 20' with a side open'to the inlet conduit I3 through a venturi I8.

crankcase II as indicated at 50. The open side of the wall as of crankcase II' coinmunicating. between the lower portion of chamber- 20 and the crankcase II. desired to place the passage 2 I in the lower portion of the crankcase II at a height approximately equal to that of the lubricant level in order to prevent rapidloss of lubricant from the crankcase into the inlet chamber 20 under transient conditions in which the inlet chamber pressure may be appreciably lower than that prevailing in the crankcase II. In such instances, the siphon operation caused by the venturi It will not relieve the, crankcase pressure rapidly In most cases, it may be enough to prevent the .pressure difference from I forcing the lubricant out of the crankcase II' very rapidly.- It isdesirable to shield the opening of passage 2I' from any direct splash or impingement 'of lubricant which. would tend to I reverse the flow of lubricant.

Exhaust conduit l2" communicates with an exhaust manifold 36. A valve, assembly, not shown, is enclosed in a cylinder head 31 which is suitably secured to the cylinder block 24 as by I have found that while any number of lubricant separating chambers may be used, in most cases one such chamber is suillcient. Therefore,

in the embodiment of my invention illustrated in Figs. 2 and 3 I haveshoWn but one such chamber I4 which communicates directly with the venturi I8 through bleeder passages, 42 and 43 instead of communicating with the venturi through passages I1 and I9 and chamber I5 as illustrated in'Fig. 1. In the'illustrated form of my invention passage 42 comprises a substantially annular groove formed in the outer face of wall 35. The groove is closed by the inner face of end plate 33 as shown in Fig. 2. Passage 4| may be simply a bore extending through the upper part of the laterally extending flange 46 of end plate 33 and through] a portion of wall 35.

The oil separating chamber I4 is defined by the substantially annular space or recess between the substantially annular flange 46 and the hub 32. In order more nearly to isolate the separating chamber 54' from the crankcase II, I'have provided a closure member in the form of a splash plate 44 suitably secured. In order to permit gas and lubricant to be drawn into the chamber I4 I have provided an opening or passage I8 in the plate 43 abovethe lubricant level in crankcase II'. It is desirable to locate the passage II in such a place thatoil is fed directly to the bearing without creating excessive splashing within the chamber I4. In order to accomplish this purpose, theplate u is provided with a baiile portion 440 which tends to direct the lubricant downwardly into the chamber I 4'. By reason of the several successive changes in direction of flow, the lubricant is'separated from the gas and drops downwardly onto and around III) the hub or boss 32 A bore 41 is provldedin the boss 32 and an opening 43 is provided in the bearing 3| in order to provide lubrication for the shaft 21. In order to provide'a return passage 23' between the separating chamber I4 and the crankcase II the plate 43 is flattened at the lower portion, as shown in Fig. 3, to provide a space between the bottom edge of plate 44 and the flange 46 of end plate 33. The gas, freed of a second passage communicatin be w en s i the lubricant, is drawn from chamber l4 through bleeder passages ll, 42 and 43 into the suction line l3 at the venturi ll. 7

Many modifications of my invention may be made. Asillustrated in the drawing, the separating chamber or chambers may be incorporated integrally. in the compressor block and end plate design so as not to be externally apparent, or the'separating chambers may be separated from the compressor. The chambers and passages described above may be formed in,any desired way in the compressor block and end plate. A splash plate is not essential to the invention as any desired separation between the chamber I4 and the crankcase il' may be provided as long as suitably positioned passages are arranged between the crankcase ii and chamber l4 above and below the lubricant levels. Furthermore,

my invention is not limited to the use of a Venturi contracta as a pressure reducing means but any sort of pressure reducing means may be employedto perform the siphon function.

While I have shown a particular embodiment of my invention, I do not desire my invention to be limited to the particular construction shown and described and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A compressor having a crankcase, a cylinder, a movable element in said cylinder for displacing a working fluid, an inlet chamber communicating with said cylinder and receiving lubricant from the external part of the refrigerant circuit, a suction line communicating with said inlet cham-' her and means for returning the lubricant entering said inlet chamber to said crankcase, said means including a pressure reducing portion in said suction line for establishing lower pressure in said crankcase than in said i et chamber.

2. A compressor having a crankcase, a cylinder,

a movable element in said cylinder for displacing a working fluid, an inlet chamber communicating with said cylinder. a suction line and means for returning any working fluid entering said crankcase to said inlet chamber, said means including a pressure reducing portion in said suction line for establishing a: lower, pressure in said crankcase than in said inlet chamber.

3. A compressor having a crankcase, a cylinder, a movable element in said cylinder for displacing a working fluid, an inlet chamber-communicating with said cylinder and receiving excess lubricant from the refrigerant circuitpa suction line communicating with said inlet chamber and means for returning the lubricant entering said inlet chamber to said crankcase and for returning any working fluid from said crankcase to said inlet chamber, said means including a pressure reducing portion in said suction line for-establishing a lower pressure in said crankcase than in said intake chamber.

4. A compressor having a crankcase chamber,

, a cylinder, a movable element in said cylinder for displacing a working fluid, an inlet chamber communicating with said cylinder, a suction line, .and means for maintaining a lower pressure in said crankcase than in said inlet chamber, said means including a pressure reducing portion in said suction line. a lubricant separating-chamber,

I means including a first passage communicating between said pressure reducing portion and said separating chamber, additional means including crankcase above the lubricant level therein and said separating chamber and further additional means including a third passage communicating between said inlet chamber below the lubricant level therein and said crankcase.

5. In a compressor having a crankcase, a cylinder, an element in said cylinder for displacing a working fluid, an inlet chamber communicating with said cylinder and means including a passage for returning lubricant entering said inlet chain ber to said crankcase, a wall of said compressor being'provided with a lubricant separating chamber, said wall having a first passage communicating between said separating chamber and said crankcase above the lubricant level in said crankcase, said wall having a second passage communicating between the lower portion of said separatingcharnber and said crankcase, said wall having a third passage therein communicating with said inlet chamber, pressure reducing means in said third passage, said wall having a fourth passage therein communicating between said separating chamber and said pressure reducing means and said wall having a fifth passage therein communicating between the lower portion of said inlet chamber and said crankcase.

said recess thereby providing a lubricant separating chamber, said member having a first opening above the lubricant level in said crankcase, said member having a second opening located below the lubricant level in said crankcase, said wall of said crankcase having aninlet' passage therein communicating with said inlet chamber, a Venturi contracta i -said inlet passage, said wall having a second passage therein communicating between said separating chamber above the lubricant level therein and the throat portion of said Venturi contracts, said wall having a third passage therein communicating between the lower portion of said separating chamber and said crankcase below the lubricant levels in said crankcase and means including a passage for returning lubricant. entering said inlet chamber to said crankcase.

'7. In a compressor having a crankcase, a cylinder, an element in said cylinder for'displacing a working fluid, aninlet chamber communicating with-said cylinder, said inlet chamber being open at one side, a removable end wall. a portion of said end wall closing said open side of said inlet chamber, said end wall having a recess, a closure member arranged substantially to close the open side of said recess thereby providing a lubricant separating chamber, said member having a first opening above the lubricant level in said crankcase, said member having a second opening located below the lubricant level in said crankcase, said wall of said crankcasehaving an inlet passage therein communicating with said inlet the pressure is substantially lower than the suction pressure of said compression means, and means for providing communication between said area of lowpressure and said crankcase at a point above the normal oil level therein.

9. In a compressor apparatus including fluid compression means, means for supplying fluid to be compressed to said compression means, and an oil-reservoir having a normal 011 level, the combination of means for creating within-said fluid supply means an area in which the pressure is substantially lower than the suction pressure of said compression means, and means for providing communication between said area of low pressure and said oil reservoir at a point above the normal oil level therein.

10. In combination with a compressor apparatus having an oil reservoir formed in the crankcase thereof and means for supplying to-said compressor fluid to be compressed, means operative responsive to the supply of fluid to' said compressor for forming an area in which the pressure is substantially lower than the suction pressure ofsaid compressor; and means providing communication between said area of low pressure and said crankcase at a point above the normal oil level therein.

11. In combination with a compressor apparatus having an oil reservoir formed in the crankcase thereof and means for supplying to said compressor fluid to be compressed, means operative responsive to the supply of fluid tosaid compressor for forming an area in which the pressure is substantially lower than the suction pressure of said compressor, and a conduit providing communication between said area of low pressure and said crankcase at a point above the normal oil level therein.

12. In combination with a compressor apparatus having an oil reservoir formed in the crankcase thereof and means for supplying to said compressor fluid to be compressed. means operative responsive to the supply of fluid to said compressor for forming an area of lower pressure than the suction pressure of said compressor apparatus, said last-mentioned means comprising a venturiforming a part of said fluid supply means, and a conduit providing communication between said area of low pressure and said crankcase at a point above the normal oil level therein.

13. In combination with a compressor apparatus having an oil reservoir to med in the crankcase thereof and means for supplying to said compressor fluid to be compressed, means operative responsive to the supply of fluid to said compressor for forming an area of lower pressure than the suction pressure of said compressor apparatus, said last-mentioned means comprising a venturi forming a part of said fluid supply means, and means forming a passageway providing communication between the crankcase of said compressor, at a point above the normal oil level therein, and the fluid supply means proximate the throat of said venturi.

14. In combination with a compressor apparatus having an oil reservoir formed in the crankcase thereof and means for supplying to saidcompressor fluid to be compressed, means operative responsive to the supply of fluid to said compressor for .forming an area of lower pressure than the suction pressureof said compressor E. JOHNSON.

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