US3189256A

US3189256A - Encapsulated motor compressor for refrigerating machines

Info

Publication number: US3189256A
Application number: US269996A
Authority: US
Inventors: Bachmann Paul Adam
Original assignee: Danfoss AS
Current assignee: Danfoss AS
Priority date: 1962-04-02
Filing date: 1963-04-02
Publication date: 1965-06-15
Anticipated expiration: 1982-06-15
Also published as: GB1035666A; DE1209577B

Description

June 15, 1965 P.A.BACHMANN 3,189,256

ENCAPSULATED MOTOR COMPRESSOR FOR REFRIGERA'I'ING HAQHINES Filed April 2, 1965 United States Patent 1 O 7 Claims. 61. 230-58) The invention relates to an encapsulated motor compressor for refrigerating machines of the type having a horizontally-disposed shaft and a cylinder head overhanging the cross-sectional plane of the motor compressor.

Prior capsules have been constructed of a sufliciently large size, that it has not been necessary to take any special precautions with respect to the protruding cylinder head. Similarly, the disposition of a sufiicient amount of oil did not cause problems because of the large size of the capsule. It is desirable, however, to have the capsule as small as possible.

It is accordingly an object of the invention to reduce the size of the capsule but at the same time providing sufficient space for the oil without increasing the oil level to any significant extent.

According to the invention, the motor compressor is closely enclosed by a capsule and the capsule is provided with an enlargement adapted to receive. the cylinder head, the motor compressor being enclosed in the capsule in such manner that the centerline of the cylinder is turned downwards so that the enlargement is at least partly filled with the oil contained in the capsule. i The size of the capsule may be significantly reduced when its main body is constructed, as it is according to the invention, independently of the protruding cylinder head. However, this reduction of size also tends to cause the level of the oil to increase and, as the quantity of oil for a certain system is provided within very narrow limits, the oil will tend to rise to a level which may, for example, be above the airgap of the electromotor. However, if the enlargement of the capsule, according to the invention, is utilized as a part of the oil sump, then a satisfactory low oil level and a reduction in the size .of the capsule can be eifectively combined.

According to a preferredembodiment of the invention, the wall of the capsule extends with a vault directly into the enlargement and the extra space thus defined is at least partly filled with oil. In the same manner, the enlargement of the capsule as a projection of the cylinder head can be vaulted and serve the same purpose. Since the enlargement is for the most part filled by the cylinder head itself, it is preferable to enlarge the space which is available for the oil sump in the same manner since the space thus provided is obtained without the external size of the entire capsule, including the enlargement, exceeding the desired predetermined size.

It is particularly advantageous for the centerline of the cylinder to be disposed with respect to the vertical centerline at an angle of about 4545". With such a disposition, a great part of the cylinder head is turned away from the oil, which means a lesser displacement of the oil, which further contributes to, a lowering of the oil level. Furthermore, this aligning of the centerline or axis of the cylinder has the advantage that the vaulted enlargement in the projection of the cylinder head does not extend the exterior dimension of the entire capsule and the vaulted continuation of the capsule extends it only to a very small extent. Furthermore, oil for lubricating purposes during the starting period of the machine can be accumulated in the bottom of the cylinder during the resting period of the machine. More- 3,189,256 Patented June 15, 1965 over, the gas pressure in the working chamber of the cylinder can be relieved without counter pressure from the oil along the upper surface of the cylinder, in contrast to an embodiment having a vertically-hanging cylinder. The angle of 45 with respect to the vertical centerline offers the best conditions with respect to external size, but an angle of 55 offers a better lowering of the oil level.

According to another advantageous embodiment of the invention, part of the silencing chamber, which borders the cylinder, dips into the oil. This extra displacing of the oil can be accepted due to the foregoing considerations. A silencer cooled by oil has the advantage that the sucked-in gas, which first has cooled the entire machine, will pass into the compressor with a lower temperature, thus increasing the efiiciency of the compressor. In this connection it is of great importance that the openings of the interconnecting channelsbetween the silencers can be located above oil level. Due to these factors, which also are related to the lowering ofthe oil level, gaskets can be eliminated between the charmbers of the silencers and the closing plates without danger that oil will be sucked in by the compressor and circulated in the refrigerating system and create noisy conditions. i

For motor compressors which have such a closely fitted encapsulation, normal helical spring mounting will only be usable to a limited extent. It is preferred to mount the motor compressor in horizontally-disposed spring pins. In this connection, the cylinder should be tilted to an extent with respect to the horizontal that it lies below one spring pin, i.e. two oppositely-located spring pins lie in the centerline of the motor compressor.

Further objects, features and characteristics of the invention will be readily apparent from the following detailed description of an illustrative embodiment taken in connection with the single figure of the accompanying drawing in which is shown a cross-sectional view of a capsule containing a motor compressor seen from above.

The motor compressor illustrated in the drawing includes a motor body 1 and has a substantially circular cross-section. The cylinderhead 2 extends beyond, i.e. overhangsjf this cross-section to a limited extent, and the cylinder head consists, as usual, of a valve plate and a valve cover. The expression "cylinder head as used herein does not only include the parts mentioned, but also includes part of the cylinder to the extent this part overhangs the cross-section of the motor compressor body. The cylinder body 3 is molded or cast as a one-piece body integral with the supporting element for the motor 1, the bearing for the motor, and both pressure silencers 6 and 7. In the same integral casting are also found the connecting channels 8, 9, 10 and 11 connecting two silencing chambers viz. a silencing chamber and the valve-chamber in the cylinder head 2. The entire unit is closed on the frontside by a cover 12, which also includes a second bearing 13 for the motor crankshaft 14, and an inlet opening 15 to the suction silencer, and an opening 16 leading to the pressure silencer. The screws which fasten the cover and the other parts of compressor, in order to simplify the illustration of the invention, are not shown. The entire motor compressor is mounted in the capsule by means of spring pins 18, said pins being disposed in corresponding grooves 19.

The capsule 17 encloses the motor compressor as closely as its contour permits, i.e. it follows the circular outline of the motor compressor along a very large part of both the crosswise and lengthwise section. Only in the area of the cylinder head 2 is an enlargement 20 of the capsule provided. The centerline 21 of the cylinder tilts downwards to such an extent that the enlargement at least partly is filled with oil 22, thus lowering the oil level 23 as much as possible.

In the basic construction of the invention, the capsule also encloses the cylinder head 2 very closely, as shown by the dotted line 24. By reason of the downwardly-directed cylinder disposition, the space 25 around .the cylinder head is also available for oil, in contrast to a construction with an upwardly-pointed cylinder disposition.

However, preferably, the wall of the capsule continues into a vault 26, which continues into the enlargement 20 of the capsule. In this manner, an extra space 27 for the oil is obtained without significantly increasing the crosswise and lengthwise dimensions of the capsule.

.It is not necessary to make the vault 26 in the plane .value a, in this case 55, the vault 28 does not affect the vertical and crosswise external size of the capsule. Furthermore, the cylinder head 2 dips into the oil 22 with only a fraction of its entire volume, which further decreases the oil level 23. In addition, the oil, which is fed for cylinder lubrication, can be collected during the rest period of the machine along the downwardly-pointed surface U of the cylinder 3. In contrast, the pressure in the working chamber of the cylinder 3 can be relieved along the upper surface of the cylinder without any counterpressure from the oil.

From the drawing it is clear that the silencing chamber 4 bordering the cylinder partly also dips into the oil sump 22. As the oil has a lower temperature than the sucked in gas stream, which heretofore has been utilized to cool down the entire motor compressor, it is possible to emit some heat from the sucked in gas stream, thus increasing the efliciency of the compressor. The heat is relatively rapidly transmitted from the oil through the capsule to the ambient areas. With the construction described, it is possible to keep the oil level 23 of the oil sump below the openings of the channels 8 and 9 in the associated silencers. It is insured that the compressor cannot suck-in oil even if the oil has entered a silencer. Thus, the demands on the gaskets of the suction silencers can be reduced and the gaskets between the cover 12 and the component 1 forming the suction silencers can be eliminated.

It will be understood that the embodiment shown can be altered and modified by those skilled in the art without departing from the scope of the invention as defined in the appended claims. Thus, the silencer chamber, for example, can be formed together with the cylinder as a one-piece component with the silencers closed at the front while the open side of the silencers can be closed by the motor-supporting body. The invention also includes a construction with only one bearing for the motor crankshaft. The invention thus consists broadly in the capsule enlargement for the cylinder head and the location thereof, especially in the case of motor compressors with a closely-enclosing capsule. It will be understood that the motor compressor per se can be of known construction.

I claim:

1. An encapsulated motor compressor for refrigerating machines comprising a capsule containing oil and a motor compressor having a horizontally-disposed shaft and a cylinder head extending beyond the cross-section of the remainder of the motor compressor, said capsule enclosing the motor compressor closely throughout and having a cross section substantially circular along at least one half the cross section and an enlargement in cross section being provided to receive the cylinder head, the centerline of the cylinder being inclined downwardly relative to the horizontal to an extent that the enlargement provides an oil sump which is at least partly filled in operation with oil contained in said capsule.

2. A motor compressor according to claim 1, wherein the wall of the capsule continues into the enlargement with a vault and the additional space thereby provided is at least partly filled with the oil.

3. A motor compressor according to claim 2, wherein the enlargement in the projection of the cylinder head is also vaulted and the additional space thus provided is at least partly filled with the oil.

4. A motor compressor according to claim 1, wherein the centerline of the cylinder with respect to the vertical centerline is disposed at an angle of 4555.

5. A motor compressor according to claim 1, comprising means defining a suction silencer bordering the cylinder and extending into the oil sump.

6. A motor compressor according to claim 5, wherein said means defining said suction silencer defines a second suction silencer and interconnecting channels with openings into the silencers, the openings of the interconnecting channels of the suction silencers being disposed in operation above the oil level in said capsule.

7. A motor compressor according to claim 1, including horizontally-disposed spring pins mounting said motor compressor in said capsule, and the cylinder being tilted with respect to the horizontal centerline and disposed below one of the spring pins.

References Cited by the Examiner UNITED STATES PATENTS 3/29 Crane 23058 1/38 McCune 23058

Claims

1. AN ENCAPSULATED MOTOR COMPRESSOR FOR REFRIGERATING MACHINES COMPRISING A CAPSULE CONTAINING OIL AND A MOTOR COMPRESSOR HAVING A HORIZONTALLLY-DISPOSED SHAFT AND A CYLINDER HEAD EXTENDING BEYOND THE CROSS-SECTION OF THE REMAINDER OF THE MOTOR COMPRESSOR, SAID CAPSULE ENCLOSING THE MOTOR COMPRESSOR CLOSELY THROUGHOUT AND HAVING A CROSS SECTION SUBSTANTIALLY CIRCULAR ALONG AT LEAST ONE HALF THE CROSS SECTION AND AN ELERGEMENT IN CROSS SECTION BEING PROVIDED TO RECEIVE THE CYLINDER HEAD, THE CENTERLINE OF THE CYLINDER BEING INCLINED DOWNWARDLY RELATIVE TO THE HORIZONTAL TO AN EXTENT THAT THE ENLARGEMENT PROVIDES AN OIL SIMP WHICH IS AT LEAST PARTLY FILLED IN OPERATIVE WITH OIL CONTAINED IN SAID CAPSULE.