US2742767A - Refrigeration apparatus, including a precooler - Google Patents

Description

A ril 24, 1956 c. F. ALSING 2,742,767

REFRIGERATION APPARATUS, INCLUDING A PRECOOLER Filed Feb. 23, 1954 2 Sheets-Sheet l W ff INVENTOR.

April 24, 1956 c. F. ALSING REFRIGERATION APPARATUS, INCLUDING A PRECOOLEJR Filed Feb. 25, 1954 2 Sheets-Sheet 2 II VVENTOR.

BY s United States Patent REFRIGERATION APPARATUS, INCLUDING A PRECOOLER Application February 23, 1954, Serial No. 411,795 8 Claims. (c1. 62--117.8)

The present invention relates to a refrigeration apparatus and system of the type in which a precooler is employed for the heated gas which is taken directly from the compressor outlet to the precooler, and returned from the precooler to the motor compressor housing for cooling the motor.

In the refrigeration systems of this type the refrigerant and entrained oil are cooled in the precooler and some of the refrigerant is condensed, and the oil and refrigerant are then delivered to the upper part of the motor compressor housing where the liquid refrigerant trickles down over the motor parts, cooling the motor, and the oil in the form of droplets runs down to an oil sump which surrounds the compressor in the bottom of the motor compressor housing. I

The effectiveness ofthe precooling coils of this type of the prior art is somewhat impaired because the temperature of the refrigerant and coils drops rapidly through this coil, which is operating in a room temperature and heat does not radiate effectively from the precooler coil part'which does not have a considerable difference in temperature from that of the air to which the heat is transferred.

In the precoolers of the prior art the latterhalf of the tubing of the precooler coil may be operating in an ambient or room temperature of 110 degrees under the most adverse conditions, and the last part of the tubing may be at temperatures of 140 to 157 degrees, while the inlet portion of the precoolermay run as high as 230 degrees F. J

One of the objects of the invention is the provision of an improved refrigeration apparatus including such a precooler in which all of the precooler tubing is maintained at a temperature which is considerably elevated above the ambient or room temperature at all times, so that all of the precooler tubing will effectively radiate and dissipate heat.

Another object of the invention is the provision of an improved precooler coil structure which radiates heat to the surrounding atmosphere more'efiiciently andwhich is simple in construction, sturdy, and adapted to be manufactured at a low cost.

Another object of the invention is the provision of an improved mode of support for the precooler coil by means of which the precooler coil not only dissipates heat from the refrigerant and oil emerging from the compressor, but it also dissipates heat taken directly from the motor housing.

Another object of the invention is the provision of an improved mode of precooler support on the motorcompressor housing which aids in dissipating or attenuating noise from the operation of the compressor, and by means of which the precooler coil is arranged in the stream of air which moves upward by convection from the motor compressor housing. I

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar I the sump and pump it along with the refrigerant for lubrireceiver 16.

parts throughout the several views.

Referring to the drawings, of which there are two sheets, accompanying the specification,

tern embodying the present invention;

Fig. 2 is a top plan view of the motor compressor and precooler unit; v I

Fig. 3 is a side elevational view of the motor sor and precooler unit.

The refrigeration apparatus embodying the invention preferably includes an evaporator 10, Fig. 1, which may comprise a box-like member of sheet aluminum having a bottom 11, rear wall 12, side walls 13 and 14, and shelf 15 extending from side wall to side wall.

The top is open but is closed by the top of the refrigerator liner to which it is secured, and the front of the evaporator is closed by an evaporator door, not shown.

The evaporator may include a receiver '16,'comprising two enlarged portions 17 and 18, joined by an easy bend Fig. 1 is a diagrammatic view of the refrigeration syscompresat 19'and mounted in a complementary slot or opening in nozzle 21, extending toward the receiver outlet 22.

From the receiver outlet a tube 23 extends along the bottom wall 11 to the bottom of which it is secured, and the tubing is arranged sinuously at 24 on the bottom wall 11, by providing the straight portions 24 and the U-shaped bends 25 and 26 joining these portions- From the bottom tubing 24, thetubing is bent upwardly at 27, on the outside ofthe end wall 13, and slopes upwardly sinuously at'28, with a plurality of straight portions which are joined by U-bends 29. I

At the shelf level the tubing is'turned inwardly through,

the wall at 30, and has a pluralityj'of straight portions 31 arranged sinuously on the bottom of the shelf 15, and joined by U-shaped bends 32. H I

At the rear end of the shelf the tubing emerges at 33 through the sidewall 14, and has a'single U-shaped bend 34 joining two straight portions 35;

The uppermost tubing 35 is bent at'36,'around the corner, and extends at 37 along the rear wall 12to an upper part of the receiver 16, 'where there-n n inlet at 38 into the upper horizontal portion 17 of receiver 16.

. The outlet from the receiver 16 and from the evapo' rater is at 39, at its upper horizontal end,,where a tube 40 extends into the end 41, andhasits openend 39 turned upwardly to be located above' anyliquid in the The outlet. tube 40, which isalso the suction tube, is arranged in heat conducting relation with the capillary tube 20, coming from'the' motor compressor. The'motor compressor unit 42 comprises an outermotor housing 43, the lower part of which 44, contains the compressor 45, which is directly connected to the shaft of the motor located in housing 43. The lower part 44 of the motor housing forms an oil sump, which is in direct communication with the rest of the motor housing and which is filled with oil surrounding the motor compressor'45, which may be immersed in the oil.

There is an oil inlet 46 in the bottom plate of the compressor 45, so that the compressor may draw oil from eating the compressor and motorL The outlet of the compressor 45 is at 47, and is con nected by means of a tubei48 with the precooler unit 49. Tube 48 extends through the wall of the motor housing 44, from the compressor outlet 47, and conducts refrigerant in the form of a compressed heated gas with entrained oil directly from the compressor to the precooler.

The inlet to the motor compressor is at 50, and is connected directly to the tube 40, which also passes through the wall of the motorhousing 44 and through the oil sump to the compressor.

The precooler condenser 49 may consist of a plurality of straight, vertical runs 51 of tubing joined by U-shaped bends 52, 53, at the top and bottom, and the outlet from the precooler unit 49 is at 54, where the precooler tubing discharges into the top of motor housing 43.

The main condenser 55 consists of a plurality of straight, vertical runs 56, of tubing, connected at the top and bottom of the U-shaped bends 57, 58. The inlet to the main condenser is at 59, from the top of the motor housing 43, and the main condenser outlet is indicated at 60, where the tubing is joined to a refrigerant drier capsule 61, comprising a tubular member provided with a filling of silica gel powder 62 between a pair of screens 63, 64. The outlet from the drier is at tube 20.

The main condenser may have its vertical passes joined by a multiplicity of welded heat dissipating fins or wires.

The motor compressor may be provided with diametrically opposite angle brackets 66, resting upon cup-shaped members 67, within which there is seated one end of a spring 68, surrounding a screw bolt 69, having a nut 70.

Screw bolt 69 also passes through a transverse frame member 71, which has its ends 72 secured to the cabinet and upon the top of which the spring 68 is seated.

The transverse frame member 71 has its central portion 73 bowed outwardly to arch about the motor compressor housing 43, and the main condenser coils 55 are also arranged in an arcuate arrangement about the outside of the motor compressor 43.

At their upper ends the main condenser coils are supported by a pair of brackets 74, mounted on the rear of the cabinet 75, and provided with a split rubber grommet 76, which surrounds the outermost U-bend 57 at each side of the main condenser 55.

At their lower ends the main condenser coils 55 are clamped by a plurality of welded clips 77 to a transverse frame member 78, the ends 79 of which are secured to the rear wall of cabinet 75.

The present precooler coil 49 is supported directly upon the motor compressor housing 43, by means of a clamping band 80, comprising a metal strip which is curved over the major portion of its length from 81 to 82 to fit the cylindrical outer surface 83 of the motor housing 43.

Brackets 78a with rubber grommets 78b secure the outermost coils of main condenser 55 to the rear panel at the lower end of said coils. The main condenser 55 and details of its support and the compressor support may be substantially as disclosed in application Ser. No. 294,091 of Harry Nadler, filed June 17, 1952, U. S. Patent N0. 2,687,625.

From the point 81 to the point 84 the band 80 is curved on a larger diameter which provides room for the precooler coils 49 between the band 80 and the cylindrical surface 83, of the motor housing 43.

At its ends the clamping band 80 has a pair of outwardly turned securing flanges 85 and 86, provided with apertures 87 for passing the screw bolt 88, having nut 89.

The outlet from the precooler coils into the top of the motor housing is again indicated at 54, and the inlet tube 48 extends directly from the precooler 49 through the lower part 44 of the motor housing into the motor compressor outlet 47.

The motor compressor housing 43 may be arranged with the forward half of the motor housing 43 under the lower edge of the rear wall of the cabinet, while the rear half of the motor compressor housing 43 is disposed rearwardly of the rear cabinet wall in the chimney, which is formed by the vertically extending passes 56 of the main condenser 55.

65, leading to the capillary Therefore, the precooler 49, which is to be carried by the motor housing 43, must be arranged on the outer half er the motor housing 43, which is that portion below the center in Fig. 2, so that the vertical passes 51 of precooler 49 may extend vertically behind the rear wall of the cabinet 75, which customarily has a cavity for receiving the from half only of the motor housing 43.

This makes only half of the periphery of the motor housing 43 available for mounting the precooler coils, of which there are too many in the particular system to have them all spread circumferentially on the motor housing 43.

Therefore, one portion, 49a, of the precooler coils is arranged with only one leg of each pair of vertical passes engaging the housing, such as the legs 51a, while the portion 49b of the precooler 49 has both of the legs 51b of each U-shaped portion directly engaging the motor housing 43.

As pointed out preliminary to the description, the precooler coils of the prior art had their efiiciency impaired by the fact that the temperature dropped rather rapidly through these coils from a temperature of 230 degrees F., for example, at the precooler inlet 47, to a temperature of, for example, 140 to 157 degrees F. for the last half of the tubing.

According to the present invention the precooler tubing is in heat conducting relation with the hot motor housing 43, and its heat dissipating temperature may be maintained, for example, at a minimum of about 173 degrees F. by the conduction of heat from the motor housing 43 to the precooler 49.

From the foregoing it will be evident that it is the last half of the precooler tubing 49, that is the portion 4911, which needs the most heat conduction to bring it up to a temperature, such as 173 degrees F, at which it can radiate heat efliciently to the surrounding ambient temperature, which may be as high as 110 degrees F.

Therefore, the last portion 49b of the precooler has its vertical passes all directly engaged with the motor housing 43, and welded to the inside of the band 80, to conduct heat readily from the band to the coils and to clamp the coils against the motor housing 43 for efiicient heat conduction.

The other earlier portion 49a of the precooler 49 is arranged with its U-shaped bends extending outwardly and with only the innermost of two legs, indicated at 51a, between the band and the motor housing 43, where these two coils are again welded to the band 80.

At this inlet end of the precooler coil 49, the temperature is already high and does not need so much heat conduction from the motor housing 43, to elevate its temperature to an efiicient level for radiating heat to the air.

Therefore, there is less heat transmitting contact between the vertical passes 51a and the band and motor housing than is true for the vertical passes 51b. The vertical passes 51 of the precooler 49 are preferably secured to the band 80 at the lower end of these vertical passes; and the band 80 is preferably arranged at the upper end of the motor housing and has heat engaging contact with the motor housing 43 from the point 81 to the point 82.

Thus the precooler coils 49 are supported in the air above the motor housing 43 and are in the current of air which is produced by convection of the air that is heated by motor housing 43.

Supporting the precooler coils 49 only at one end permits the other ends and U-shaped bends 52 to be free for vibration, which will dissipate in some measure the vibration and motor compressor noise that is transmitted to the free ends 52 of the precooler coils 49, and attenuated by the vibrating action of the precooler coils 49 on the motor housing 43.

The springs 68 may be clamped fixedly by tightening nuts 70 on cups 67 and bolts 69 during shipment, but

- r the nuts are loosened before operating the system; and the springs 68 are adapted to absorb vibration of the motor compressor 43 and precooler 49.

It will thus be observed that the present refrigeration apparatus maintains a precooler temperature throughout, which is sufliciently elevated above the ambient temperature to radiate heat elfectively to the surrounding air, and more heat is dissipated from the motor housing and from the refrigerant and oil in the precooler.

The result is a more efiicient motor cooling by the precooler arrangement, and motor compressor noise is also substantially reduced.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited tothe' precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a household refrigerator, a motor compressor and precooler unit comprising, a housing having an upper,

portion enclosing a motor, andla lower" portion forming an oil sump communicating with the upper portion and surrounding a compressor directly'driven by said motor, a precooler coil having its inlet directly connected through the wall of the lower part of said'housing to the compressor outlet to remove .the hot compressed gas immediately from the compressor, said precooler unit comprising a plurality of upwardly and downwardly extending passes of tubing arranged parallel to each other and joined at the top and bottom by U-shaped, tube for- Y mations, the said precooler coils being in one continuous length of tubing and discharging into the upper part of said motor housing, all of said precooler coils having'their lower D -shaped portions mounted on said motor compressor housing in heat conducting relation with said housing to raise the temperature of said precoo ler coils by heat conduction from the motor housing to an elevated temperature for more efficiently radiating heat to the surrounding air, the said precooler coils being fixedly clamped to said motor housing at their lower ends and having their upper ends free for limited vibration and dissipationof noise.

2. In a household refrigerator, a motor compressor and precooler unit comprising, a housing having an upper portion enclosing a motor, and a lower portion forming an oil sump communicating With the upper portion and surrounding a compressor directly driven by said motor, a precooler coil having its inlet directly connected through the wall of the lower part of said housing to the compressor outlet to remove the hot compressed gas immedi ately from the compressor, said precooler unit comprising a plurality of upwardly and downwardly extending passes of tubing arranged parallel to each other and joined at the top and bottom by U--shaped tube formations, the said precooler coils being in one continuous length of tubing and discharging into the upper part of said motor housing, all of said precooler coils having their lower U-shaped portions mounted on said motor compressor housing in heatconducting relation with said housing to raise the temperature of said precooler coils by heat conduction from the motor housing to an elevated temperature for more efiiciently radiating heat to the surrounding air, the said precooler coils being fixedly clamped to said motor housing at their lower ends and having their upper ends free for limited vibration and dissipation of noise, the said precooler coils being arranged in two sections with the section that receives the refrigerant first from the compressor having alternate passes clamped to the i motor housing, and the section that receives refrigerant last from the motor compressor having all of its vertical passes clamped to the motor housing, so that the last part of the precooler tubing which needs the most heat conduction to bring it up to an efiicient radiating temperature has a maximum area in contact with said motor housing. t v

3. In a household refrigerator, the combination of an insulatedcabinet having a back panel, a transverse frame member carried by said back panel, and having an outwardly extending central portion for passing about a motor compressor housing, a motor compressor having an external housing, spring means engaging said frame member and supporting said motorcompressor housing, and a precooler coil comprising a plurality of vertical passes joined by U-shaped bends, said coils having their lower .ends secured in heat conducting relation with an upper part of said motor compressor housing, for maintaining all parts of the pre-cooler coil at an elevated temperature for efiiciently radiating heat from the pre-cooling coils to the surrounding atmosphere, the pre-cooler coils being welded to one portion of a substantially cylindrical bandextending about said motor housing, the other portion of said band being secured in heat conducting relation With said motor compressor housing, the said coils being arranged in former and latter sections, with the latter sections having a greater heat conducting contact area between the coils and band and motor compressor housing.

, 4. A motor compressor and pre-cooler unit comprising a housing having an upper portion enclosing a motor and a lower portion forming an oil sump communicating with the upper portion and surrounding a compressor directly driven by said motor, a pre-cooler coil having its inlet directly connected through the wall of said lower part of said housing to the compressor outlet to remove the hot compressed gas immediately from the compressor, said pre-cooler unit being mounted upon and extending upwardly from said motor compressor housing in heat con ducting relation with said housing to raise the temperature of said pre-cooler coils by heat conduction from the motor housing to an elevated temperature, for eficiently radiating heat to thesurrounding air, the other end of said pre-cooler,

coils being connected to discharge into a top portion of said motor housing, the said pre-cooler coils being welded to a metal band, and the said band having heat exchanging contact with substantially half of the periphery of said motor housing, the coils engaging over substantially the other half of the motor housing.

5. A motor compressor and pre-cooler unit comprising a housing having an upper portion enclosing a motor and a lower portion forming an oil-sump communicating with the upper portion and surrounding a compressor directly driven by said motor, a pre-cooler coil having its inlet directly connected through the wall of said lower part of said housing to the compressor outlet to remove the hot compressed gas immediately from the compressor, said pre-cooler unit being mounted upon and extending upwardly from said motor compressor housing in heat conducting relation with said housing to raise the temperature of said pre-coolercoils by heat conduction from the motor housing to an elevated temperature, for efiiciently radiating heat to the surrounding air, the other end of said pre-cooler coils being connected to discharge into a top portion of said motor housing, the said pre-cooler coils being welded to a metal band, and the said band having heat exchanging contact with substantially half of the periphery of said motor housing, the coils engaging over substantially the other half of the motor housing, the said coils comprising a plurality of vertical passes joined by U bends, and said coils comprising a first portion and a second portion, the said second portion having all of the legs of said coils between said band and said motor housing for more effectively raising the temperature of the latter portion of the pre-cooling coil.

6. A motor compressor and pre-cooler unit comprising a housing having an upper portion enclosing a motor and a lower portion forming an oil sump communicating with the upper portion and surrounding a compressor directly driven by said motor, a pre-cooler coil having its inlet directly connected through the wall of said lower part of said housing to the compressor outlet to remove the hot compressed gas immediately from the compressor, said pre-cooler unit being mounted upon and extending upwardly from said motor compressor housing in heat conducting relation'with said housing to raise the temperature of said pre-cooler coils by heat conduction from the motor housing to an elevated temperature, for efiiciently radiating heat to the surrounding air, the other end of said pre-cooler coils being connected to discharge into a top portion of said motorv housing, the said pre-cooler coils being welded to a metal band, and the said band having heat exchanging contact with substantially half of the periphery of said motor housing, the coils engaging over substantially the other half of the motor housing, the said coils comprising a plurality of vertical passes joined by U bands, and said coils comprising a first portion and a second portion, the said second portion having all of the legs of said coils between said band and said motor housing for more effectively raising the temperature of the latter portion of the pre-cooling coil, and the first portion of said coils having alternate legs of said vertical passes located between the said band and motor housing for a diminished conduction of heat from motor housing to coils in this portion.

7. In a refrigeration apparatus, the combination of an insulated cabinet having its rear wall provided at its lower end with a cavity for receiving substantially half of a motor compressor unit, a transverse frame member carried by said rear wall and bulging outwardly at its central portion to provide room for the motor compressor, a motor compressor unit carried by said transverse frame member and having substantially half of its volume in said cavity and the other half projecting rearwardly outside said rear wall, and a pro-cooler condenser comprising a plurality of vertical passes joined by U bends carried by said motor compressor on its outwardly projecting portion, the said precooler coils extending upwardly outside of said rear wall and above said cavity by virtue of their arrangement on the outer part of said motor compressor housing in the stream of air moving upward by convection from said motor compressofhousing, said pre-cooler coils being welded adjacent their lower ends'to a metal band, and said band clamping the welded portions of said coils against said motor housing.

8. In a refrigeration apparatus, the combination of an insulated cabinet having its rear wall provided at its lower end with a cavity for receiving substantially half of a motor compressor unit, a transverse frame member carried by said rear wall and bulging outwardly at its central portion to provide room for the motor compressor, a motor compressor unit carried by said transverse frame member and having substantially half of its volume in said cavity and the other half projecting rearwardly outside said rear wall, and a pre-cooler condenser comprising a plurality of vertical passes joined by U bends carried by said motor compressor on its outwardly projecting portion, the said precooler coils extending upwardly outside of said rear wall and above said cavity by virtue of their arrangement on the outer part of said motor compressor housing in the stream of air moving upward by convection from said motor compressor housing, said pre-cooler coils being welded adjacent their lower ends to a metal band, and said band clamping the welded portions of said coils against said motor housing, the said band itself engaging the motor housing over the major portion of its periphery for conducting heat through the band to said coils from said motor compressor housing.

References Cited in the file of this patent UNITED STATES PATENTS 2,093,471 Newill Sept. 21, 1937 2,160,018 Higham May 30, 1939 2,597,243 Hubacker May 20, 1952 2,638,753 Doeg May 19, 1953 2,667,762 Hornaday Feb. 2, 1954

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