US3171588A

US3171588A - Hermetic compressors having vertical crankshafts

Info

Publication number: US3171588A
Application number: US196821A
Authority: US
Inventors: Robert W Ayling
Original assignee: Westinghouse Electric Corp
Current assignee: McQuay Perfex Inc
Priority date: 1962-05-22
Filing date: 1962-05-22
Publication date: 1965-03-02
Anticipated expiration: 1982-03-02

Description

March 2, 1965 w AYLlNG 3,171,588

HERMETIC COMPRESSORS HAVING VERTICAL CRANKSHAFTS Filed May 22, 1962 3 Sheets-Sheet 1 March 2, 1965 R. w. AYLING 3,171,588

HERMETIC COMPRESSORS HAVING VERTICAL CRANKSHAF'TS Filed May 22, 1962 5 Sheets-Sheet 2 Invenio'r: Rain-2 2 wflywag,

March 2, 1965 R. w. AYLING HERMEIIC COMPRESSORS HAVING VERTICAL CRANKSHAFTS Filed May 22, 1962 3 Sheets-Sheet 3 United States Patent Oii ice A 3,l7l,5 88 Patented Mar. 2, 1965 3,171,588 HERMETIC COMPRESSGRS HAVING VERTICAL CRANKSHAFTS Robert W. Ayling, Staunton, Va., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed May 22, 1962, Ser. No. 196,821 3 Claims. (Cl. 23tl206) This invention relates to refrigerant compressors, and relates more particularly to refrigerant compressors having vertical crankshafts.

A refrigerant compressor which pumps a refrigerant that is miscible with its lubricating oil can be damaged on start up after the refrigerant has migrated to its crankcase during a period when the compressor is not operating, and the refrigerant has flooded the crankcase. The flooding of the crankcase also results in start up noise, and in excessive starting power requirements.

An object of this invention is to reduce the flooding of the crankcase of a refrigerant compressor during its off periods.

This invention will now be described with reference to the annexed drawings, of which:

FIG. 1 is a side view, partially in section, of a four cylinder refrigerant compressor embodying this invention;

FIG. 2 is a side view partially in section, of another four cylinder refrigerant compressor embodying this invention, and

FIG. 3 is a section along the lines 3-3 of FIG. 2.

Description FIG. 1

An upper shell it is welded to a lower shell 12, the latter having an oil sump 13 in its lower portion, the housing so formed being known as a hermetic one. An electric motor 8 having a cover 14, has a rotor 9 attached to a vertically extending crankshaft 15 which has throws 16 and 17 connected to piston rods 18 and'19 respectively, of pistons 21 and 2t! respectively, in compressor cylinders 23 and 22 respectively. The cover 14 is attached by a strap 24 and coiled spring 43 to the shell 12, the spring 43 and a similar spring which is not shown, behind the cover 14, opposing the rotational torque of the motor. The cylinders 22 and 23 are cast integral with an inner shell 25, and have

heads

26 and 27 respectively, which contain the usual suction and discharge valves which are not shown. Discharge tubes 23 and 29 are connected to the

cylinder heads

26 and 27 respectively, and to outlet tube 37. Formed to the cylinders above the latter is a bearing housing 3t containing spacedapart bearin s 31 around the shaft 15 between the motor 8 and the cylinders 22 and 23. The bearings 31 have a passage 42 therebetween which opens into a passage 43 connecting with crankcase compartment 24. Joined to the cylinders below the latter and which forms the lower portion of the inner shell 25, is a sleeve 35, to the lower portion of which is attached another bearing housing 32 containing a bearing 33 around the lower end of the shaft 15.

The lower end of the housing 32 is cylindrical and has therearound the upper portion of a coiled spring 34, the lower portion of which rests in a pan 36 on the bottom of the shell 12. Between the centers of the tops of the motor cover 14 and the shell 1% there is another coiled spring 33. The springs 34 and 38 resiliently support the motor-compressor unit within the hermetic casing consisting of the shells and 12. Suction gas tube 40 extends through the shell it for supplying suction gas to cool the motor 8 as is usual in hermetic units. Suction ports 39 connect the suction valves of the compressor cylinders with the space around the motor.

The numeral 41 indicates the normal oil level in the sump 13. The pan 34 immersed in the oil has openings 44 for facilitating the entrance of oil into the pan. The lower end of the shaft 15 restson a thrust Washer 45, the lower edge of which is seated on a shoulder 46 on the housing 32 near its bottom, and has a central opening 47 extending therethrough. The bottom of the shaft has a central bore 51) connecting with the opening 47 and connecting with a radial bore 51 which opens into a clearance opening 52 within the housing 32 below the lower end of the bearing 33. A vertically extending, off center bore 55 within the shaft 15 has its lower end opening into the bore 51, and near-its upper end opens into the lower end of a slanted bore 56, the upper end of which extends through the side of the shaft opposite the bore 55, into the space around the shaft. A groove 57 in the shaft 15 connects the bore 56 with the upper hearing 31. A radial bore 58 connects the bore 55 with the lower bearing 31. A radial bore 58 connects the bore 55 with the bearing 35.

The radial bore 51 acts as a centrifugal pump supplying oil from around the bottom of the thrust washer 45 through the bore 55 to the

bearings

33 and 31. The oil at the top of the bore 55 cannot because of centrifugal force be thrown out through the slanted bore 56, but any gas mixed with the oil does pass out the slanted bore 56. The bearing housing 32, the sleeve 35, the cylinders of the compressor and. the bearing housing 39 together form a partition enclosing the crankcase compartment 24 and separating the latter from the motor 8 and the oil sump 13.

A tube so has a horizontally extending lower portion which extends through the sleeve into the crankcase compartment 24, and has a vertically extending upper portion with an open top 62 which is above the axes of the cylinders of the compressor, and above the level 63 of mixed oil and refrigerant which is the highest level it would reach during shut down.

Operation of FIG. 1

in operation, suction gas from an associated evaporator which is not shown, passes through the tube into the space around the motor 3 and passes over the latter for cooling it. The suction gas then passes through the suction ports 39 and the associated suction valves into the compressor cylinders 22 and 23 where it is compressed by the pistons 21 and 22 respectively, and passes through associated discharge valves into the

tubes

28 and 29 and into the discharge tube 37.

Oil from the crankcase sump is drawn through the opening 47 in the thrust washer into the central bore St) in the bottom of the crankshaft and into the radial bore 51 which forms a centrifugal pump. The oil is pumped into the eccentric bore and from the latter through the radial bore 59 into the lower bearing 3-3, and from the bores 56 and 58 into the bearings 31. Gas which enters the bore 55 passes out the slanted bore 56. Gas blowby past the pistons Ztl and 21 produces pressure in the crankcase compartment 24. The gas blowby past the pistons in normal operation tends to blow any oil leaking into the crankcase compartment from the latter through the tube 68 into the sump 13. At shutdown, oil or the oil-refrigerant mixture is prevented from entering the crankcase compartment since its only vent passage is the tube till, the upper end of which is located above the maximum level 63 which the oil-refrigerant mixture can reach.

Some liquid may enter the crankcase compartment through the lubricating passages and bearing clearances during a prolonged shutdown, but flooding is prevented or minimized.

Description of FIGS. 2 and 3 The embodiment of the invention of H65. 2 and 3 is essentially the same as that of FIG. 1, the principal difference being that instead of using an external tube to vent the crankcase compartment, the vent passage is formed by a hole drilled through a boss cast on the inner shell around the crankcase compartment.

Referring now to FIGS. 2 and 3, since most of their components are similar to corresponding components of FIG. 1 they are given the same reference characters.

FIGS. 2 and 3 also differ from FIG. 1 in that FIG. 3 shows additional cylinders 70 and 71 having

heads

72 and 73 respectively, with FIG. 2 showing the head 73; in that the

discharge tubes

28 and 29 are shown on FIG. 2 as discharging into a manifold 74 to which the outlet tube 37 is connected; the external vent tube 60 is not used; a boss 76 is cast as part of the inner shell 25, and a vent passage 77 having an inlet within the crankcase compartment and having an outlet 78 above the axes of the compressor cylinders and the maximum level 63 the mixed oil and refrigerant can reach during shutdown. The vent passage 76 performs the same function as the vent tube 60.

Another advantage of this invention is that when the compressor is used as a heat pump compressor, when de frost of the associated outdoor coil is started, the sudden increase in suction pressure cannot drive the oil up into the running gear and cause noise as would otherwise occur.

What is claimed is:

1. In a refrigeration unit having a compressor with a vertically extending crankshaft, upper and lower throws on said crankshaft, upper and lower cylinders having connecting rods connected to said upper and lower throws respectively, an electric motor above said cylinders having a rotor connected to the upper portion of said crankshaft, an outer shell around said motor and compressor and having its bottom spaced below the lower end of said crankshaft and forming an oil sump, a lower bearing around the lower portion of said crankshaft, a bearing housing around said bearing, an upper bearing around said crankshaft between said motor and said cylinders, a

bearing housing around said upper bearing, an inner shell spaced inwardly of said outer shell and attached to said cylinders and said motor, said outer shell having a suction gas opening opposite said motor, the space between said inner and outer shells connecting with the space between said outer shell and said motor, means including a passage within said crankshaft for pumping oil from said sump to said bearings and for causing refrigerant vapor mixed with said oil to separate from said oil and to flow outwardly from said passage into the space around said crankshaft, and means including said cylinders and said housings forming a crankcase compartment around said throws and the lower portion of said crankshaft above said lower bearing, said compartment having a vent opening below said lower. throw, the combination of a vent passage having its inlet connected to said opening and having its outlet in said space between said inner and outer shells above the axis of said lower cylinder.

2. The invention claimed in claim 1 in which said vent passage is a tube.

3. The invention claimed in claim 1 in which said inner shell is a casting integral with said cylinders, and in which said vent passage is formed within said casting.

References Cited by the Examiner UNITED STATES PATENTS 2,048,025 7/36 Philipp.

2,156,943 2/39 Heller 230206 X 2,228,364 1/41 Philipp 230-58 2,243,466 5/41 Kucher 23058 X 2,738,919 3/56 Rusch et al 230206 X 2,898,072 8/59 Buschmann 230-206 2,963,113 12/60 Ayling 230206 X 3,008,629 11/61 Gerteis 230-206 X 3,021,995 2/62 Neubauer 230206 X LAURENCE V. EFNER, Primary Examiner.

JOSEPH H. BRANSON, JR., Examiner.

Claims

1. IN A REFRIGERATION UNIT HAVING A COMPRESSOR WITH A VERTICALLY EXTENDING CRANKSHAFT, UPPER AND LOWER THROWS ON SAID CRANKSHAFT, UPPER AND LOWER CYLINDERS HAVING CONNECTING RODS CONNECTED TO SAID UPPER AND LOWER THROWS RESPECTIVELY, AN ELECTRIC MOTOR ABOVE SAID CYLINDERS HAVING A ROTOR CONNECTED TO THE UPPER PORTION OF SAID CRANKSHAFT, AN OUTER SHELL AROUND SAID MOTOR AND COMPRESSOR AND HAVING ITS BOTTOM SPACED BELOW THE LOWER END OF SAID CRANKSHAFT AND FORMING AN OIL SUMP, A LOWER BEARING AROUND THE LOWER PORTION OF SAID CRANKSHAFT, A BEARING HOUSING AROUND SAID BEARING, AN UPPER BEARING AROUND SAID CRANKSHAFT BETWEEN SAID MOTOR AND SAID CYLINDERS, A BEARING HOUSING AROUND SAID UPPER BEARING, AN INNER SHELL SPACED INWARDLY OF SAID OUTER SHELL AND ATTACHED TO SAID CYLINDERS AND SAID MOTOR, SAID OUTER SHELL HAVING A SUCTION GAS OPENING OPPOSITE SAID MOTOR, THE SPACE BETWEEN SAID INNER AND OUTER SHELLS CONNECTING WITH THE SPACE BETWEEN SAID OUTER SHELL AND SAID MOTOR, MEANS INCLUDING A PASSAGE WITHIN SAID CRANKSHAFT FOR PUMPING OIL FROM SAID SUMP TO SAID BEARINGS AND FOR CAUSING REFRIGERANT VAPOR MIXED WITH SAID OIL TO SEPARATE FROM SAID OIL AND TO FLOW OUTWARDLY FROM SAID PASSAGE INTO THE SPACE AROUND SAID CRANKSHAFT, AND MEANS INCLUDING SAID CYLINDERS AND SAID HOUSING FORMING A CRANKCASE COMPARTMENT AROUND SAID THROWS AND THE LOWER PORTION OF SAID CRANKSHAFT ABOVE SAID LOWER BEARING, SAID COMPARTMENT HAVING A VENT OPENING BELOW SAID LOWER THROW, THE COMBINATION OF A VENT PASSAGE HAVING ITS INLET CONNECTED TO SAID OPENING AND HAVING ITS OUTLET IN SAID SPACE BETWEEN SAID INNER AND OUTER SHELLS ABOVE THE AXIS OF SAID LOWER CYLINDER.