USRE23000E

USRE23000E - Removable cooling unit for

Info

Publication number: USRE23000E
Authority: US
Priority date: 1941-07-30
Publication date: 1948-05-11
Also published as: US2336735A

Description

May 11, 1948. F. M. JONES REMmmaLE COOLING UNIT FOR GOMPARTMENTS Original Filed July 3D, 1941 5 Sheets-Sheet l o: ma;

May 1l, 1948. F. M. JONES REMOVABLE COOLING UNIT FOR COMPARTMENTS `original Filed July 30, 1941 e sheets-sheet 2 ns.. w

a 4 .tm r f mz@ Q dJ v. .t m. 6 .L nM Mt 9 F I /A F50:

F. M. JONES May 11, 1948.

REMOVABLE COOLING UNIT FOR COMPARTMENTS 6 sheets-sheet 3 Original -Fled July 30, 1941 64 Invenolfl ttor-n.29.

. May 11, 194.8. F. M. JONES REMOVABLE COOLING UNIT FOR COMPAR'MENTS Original Filed July 30, 1941 6 Sheets-Sheef 4 Fig-1o 2.6 ./zlo

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May 11, 194s. F M. JONES Re. 23,000

REMOVABLE COOLING UNIT FOR COMPARTMENTS Original Filed July 30, 19.41 6 Sheets-Sheet 5 Fig# 11 0 LY 1 M1 wf"- l x00;

T 'Il l May l1, 1948. F. M. JONES REMOVABLE COOLING UNIT FOR COMPARTMENTS Original FiledJuly 50, 1941 6 Sheets-Sheet 6 ZIO /iss 7 di ,1 nn n o F IM L. m FMH, 8

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Reissues! May ll, 1948 nEMovABLE coouNG nNrr son ooMrAarMEN'rs Frederick M. Jones, Minneapolis, Minn., assignor to The U. S. Thermo Control Co., Minneapolis, Minn., a corporation of Minnesota.

Original No. 2,336,735, dated December 14, 1943,

Serial No. 404,596,July 30, 1941. ApplicationV for reissue January 6, 1947, Serial No. 720,464

My invention relates to a removable cooling unit; for compartments of trucks, railroad cars and the like employed in transporting perishables and toa method of cooling such compartments, and hasffor its object to provide a simple and compact self-contained cooling unit positioned at the top and at the front end of said compartment.

Perishables such as meatsvegetables, fruits and the like are transported in what are known asv refrigerator cars by rail and, to a greatly increasing degree at the present time, in trucks and truck trailers. This transportation, taking place as it does over long routes which in the summer time are at high temperatures throughout and even in the winter time may be in part at high temperatures and in part at freezing temperatures, requires artiilcial cooling or heat,- ing in order to preserve said perishables in suitable condition for use as food.

In the case of refrigerator railroad cars, heavy cooling means such as large ice compartments or large and heavy -refrigerating plants can be practically employed. This is not true of trucks and trailers, where the necessary limitations of their use call for cooling means of relatively low weight and so positioned as to take up little as possible of the space within the transporting compartment. t

It is a principal object of my invention, therei fore, to provide a Acooling unit small in size and weight, and positioned, together with the airconducting passages, so as to occupy substantially none of the storage space within the vehicle compartment.

A, It is a further object of my invention to provide a unit which shall be mounted in the front wall of the compartment partly outside and partly inside and having its top adjacent the top wall of the compartment.

It is a further and particular object of my .in-

vention to provide a cooling unit embodying ay single unitary casing wherein is mounted allof the instrumentalities, including the power unit, ior producing necessary movements of air and means for cooling or otherwise conditioning said air and means for controlling and-operating the several instrumentalities.

It is a further object of my invention to provide a unit embodied in such a casing wherein the heating parts of the unit or the parts oi' the unit which normally give oil heat are located outside oi.' the compartment to be cooled and the cooling part of the unit or the part which may deliver cooled air is located inside of the compartment.

Itis a further object of my invention to provide 4 Claims. (Cl. 6ft-117) operated by an expansion thermostat for causing said controlling means to efi'ect control of operation of the gas enginein response to changes of temperature of the air about said thermostat.

The full objects and advantages oi my invention will appear in connection with the detailed description which will now be given, and the novel features by which the above noted advantageous results are obtained will be particularly pointed out in the claims.

In the drawings illustrating an application of my invention in one form:

Fig. 1 is a side sectional elevation view through the cooling unit as the same is applied to the upper part of a food storage compartment such as that of a truck.

Fig. 2 is a plan view with some parts in section and with the food compartment top removed to show that part of my cooling mechanismiound on the inside of the food compartment.

Fig. 3 is a perspective detail view showing the vforms of opening employed for leading air out of the main air trunk. I

Fig. 4 is an end elevation view taken on line 4--4 of Fig. 2.

Fig. 5 is a top plan view of the entire unit as positioned in a food compartment with the top wall of said compartment removed.

Fig. 6 is a side elevation view of the entire unit as it appears when not associated with the front wall of the food compartment.

Fig. '1 is a sectional elevation view through one wall of the unit taken on line 1--1 of Fig. l.

Fig. 8 is a fragmentary sectional view taken on line V8--8 of Fig. 7.

Fig. 9 is a transverse sectional view taken on line 9--9 of Fig. 1 and viewed in the direction of the arrows.

Fig. 10 isa transverse sectional view taken on line itl-i0 of Fig. 1.

Fig. 1l is a sectional transverse view taken on line II-ll of Fig. 1. f

Fig. 12 is a sectional transverse view taken on line I2-I2 of Fig. 1. v

Fig. 13 is a diagrammatic plan view showing the relation of the different operating parts to each other and to the chambers forming the unit.

Fig. 14 is a sectional elevationV view oi the thermostatic carburetor control Vtaken on line Il-il `or truck trailer.

3 Fig. 16 is an enlarged fragmentary sectional view through a corner of the casing and carburetor control mechanism and fiuid expansion mem- As illustrated, and referring first to Figs. 5

, and 6, I provide a unitary interconnected'casing tops to horizontal tubular supports 28 and 29`Vl and at their bottoms to lower horizontal tubular supports 30 and 3I, as shown Iin Fig. 10. As shown in Figs. 1 and 9, the

supports

28, 29, 38

the front part I9 and inside of the

side walls

23 and 24.

There is thus enclosed a front chamber 32v which in addition to the grill 22 in the top is provided with grills 33 in each side wall, Fig. 6. A grill 34 extends across the greater part of the bottom of the front part I9 and openwork indicated by holes 35 is provided in a Arear wall 35, Fig. 9, all of which gives very free' circulation of air throughout all parts of front chamber 32. The end wall 36, as shown in Fig. l, extends substantially across the rear of chamber 32 and has on each side thereof' insulation indicated at 31 and 38 of Fig. 1 excepting for a bearing housing 39 the use of which will be later described and a depression 48 for receiving an extension of a shaft member also referred to later.

'l'here is thus formed an insulated wall 4 I, Figs. 1 and 5, which separates the chamber 32 from the part of the unit which passes through the front wall of the truck into the interior of the truck compartment. This part of the unit comprises a top wall 42,

side walls

43 and 44, and a bottom wall 45, Vas best shown in Fig. 9, which walls are united at their corner junctions to the horizontal tubular supports 28. 28, 38 and I9 to the rear part of the casing 28, as shown in "and/3| are spaced considerably below the top of ful] and dotted, lilies in Figs. 1 and 9. The

Walls

42, 43', 44 and 45 enclose a rear chamber 48 provided with an innerz end wall 41, Fig. 1, which abuts the insulation V31 and'wall 4I and an outer end 'wall 48,- 1. This outer end wall has a large inlet opening indicated at 49 in Figs. 4 and 11 and an air outlet opening 58 rectangular in shape and extending across the top of wall 48.

From the above description it will appear that the unit casing encloses a front chamber 32 and 'unitary casing is an essential and exceedingly important feature ofmv invention as the same is combined or applied to the food storage compartment oi' a transport vehicle, such as a truck For, as will be pointed out in detail hereinafter, the larger front chamber will be applied to the front wall of such a compartment so that it isentirely outside of the compartment, its numerous grills and openings lead. ing directly to atmosphere, and it will houseall the heat-producing and heat-withdrawing instruing for this chamber and the chamber itself and its contents, which'may tend to cool the air, are located entirely within the food storage compartment, but positioned at the central top where practically no effective storage space is used.

The unit is applied yto the front wall of the storage compartment, so that it may be readily removed, if that becomes at any time desirable, in the following manner. A rectangular opening 53 is formed in the insulated front wall 54 of the compartment. This opening has applied thereto a frame 55 which is formed with

vertical side walls

56 and 51 and top wall 58 and bottom wall 59, as shown in Fig. 9, and which walls are adapted to engage the edge walls forming the opening 53 extending through the front Wall of the truck. Laterally extended. side flanges 5I and 52 and top and bottom flanges 68 and GI extend from the

walls

56 and 51, and 58 and 59 respectively and engage the outside of the front wall 54 of the truck.

The usual construction of food transport vehicles is well shown inA Fig. 5, wherein an outer shell 62 of suitable material such as metal and a similar inner shell 63 are spaced apart, the space being filled with insulation 64. After the opening 53 has been formed in the truck body vertical

4wooden frame members

65, 66 are positioned between the outer and

inner shells

62 and 63, and may extend from the top toward the bottom downward as far as may be desired. Secured to these frame pieces 65 vand 66 by meansof bolts 61 are angle irons 68 and 69.A The bolts 61 also pass through bracket flanges 18 fast on the tubular members 29 and 3i, as shown in detail in Figs. 'I4 and 8, and by this means the.

entire unit is held rigidly assembled in the front wall 54 of the food storage compartment and yet so assembled that by merely removing the bolts 61 the vunit may bewithdrawn therefrom. Brace rods 1I 12 and 13 extend in arched relation across the rear wail of -the unit, as shown in Figs. l, 4 and 6 and hold the parts rigidly together.

.Having reference particularly to Figs. l, 10 and 13, within the iront chamber 32 and transversely in alinement are a gas engine 15, a carburetor 16 therefor and a compressor 11. A support for the engine is indicated at 18 of Fig. 10 as being secured by bolts 19 to bracket plates supported by tubular supporting

members

25 and 38. Similarly a support 88 for the compressor 11 is supported upon tubes 25 and 3|.

Fast on motor shaft 8I is a pulley 82 which drives a pulley 83y operating the compressor shaft 84, Fig. 10, by means of a belt 85. Belt 85 also passes over a pulley 86 on fan shaft 81. The fan shaft 81,y as clearly shown in Fig. 1, lhas its fori ward end extended through a supporting bearing 88 and carries a fan 89 located in front chamber l about the condenser coil.

Also the condenser 90, as clearly shown in Fig.

- 1, is at the front end of front chamber 32 prorJecteri forwardly oi4 the truck at the upper part thereof. where the pressure of the air as the truck moves along the highway will aid the ian I9 in drawing air through the condenser. This air also is free to circulate all about the engine 15 and the compressor 11 and leave in practically all directions through the

numerous openings

22, 33. 34 and 35 provided f-or that purpose. Because of` this freedom of air to move out of compartment 32 directly into the `open air in all directions.l it will be apparent that, when cooling of the compartment takes place, none of the heat released by the gas engine, the compressor and the condenser, will affect the walls 54 of the food storage compartment 96 Within the truck, or tend to warm the food storage compartment therein.

The blower 92 within front compartment 46 has a housing formed in the back by the closure 41 and in front by a typical blower casing' 91 shown in outline in Fig. 12. The casing 91 is formed with a central opening 98 and with an internal passageway 99 surrounding the casingA andthe blower 92 which progressively expands'l in width, as shown in Fig. 12, to the discharge outlet into a top passageway lili within a casing |02 leading to the air outlet opening 50 from the inner casing portion of the complete cooling unit. A curved top wall |03, Fig. 1, aids in directing the air moved by blower 92 to and through the passageway |0|.

This passageway |0| is extended'nto a. passageway |09 formed by a rectangular casing I I0, Figs. 2 and 4, which extends along the central top of the food compartment 96 directly in contact with the liner |01.

As shown at Fig. 2, the end oi the duct passageway |09 approaches the rear wall i|2 of the food storage compartment 96. The duct passageway |09 has formed in its side walls ||3 and ||4 a series of openings ||5 and ||5. These openings are specifically of the form indicated in Fig. 3, wherein a lip ||6 is pressed inwardly between the top wall of casing I |0 and the bottom wall ||1. There also are formed in the side walls ||9 and ||9 of the top duct |0I, Fig. 1, similar openings |20, Fig, 2, and 2|, Fig. 1only the lips 22, Fig. 2, are pressed outwardly andibackwardly. Y

The arrangement of the several ducts IIE, H and of ducts and |2| is such as to cause a sheet of cooled air to iiow from the central duct ||1 outwardly along the top of the food storage compartment and to move against all of the four surrounding walls of the compartment, thence downwardly along said wallsto the door of the compartment, as clearly shown in Figs. 2 and 4, with the result that an envelope of cooled air is caused to be formed and to move along allinterior walls of the fo'od storage compartment.

This is the outward action of the blower. The inward or suctionaction of the blower causes air to move through an evaporator heat exchanger |23 for-med of a series of transverse pipes |24 connected by pipe coils or unions |23 at the sides,

as shown in Fig. 1. The opening 49 to the evaporator heat exchanger |23 is wel! shown in Fig. 11. The suction of `blower 92 causes the air to `move through the opening 49 underneath the outlet duct passageways |0| and ||1 and thence through to the opening 93 into the blower casing and through the blower 92 and back into the ducts |0| and ||1.

As shown in Fig. 4, the result of this operation is to draw into the blower and through the opening |23 air toward the top of the surrounding wall-contacting envelope of cooled air. This. of course, -will always be the warmest air in the food storage chamber 36; and vbecause all of the walls within the food storage chamber are wiped by the moving envelope of cooled air which constantly takes up any heat tending to enter the food storage compartmentthroughthe walls, channeling of air currents andpoclceting and-r resulting dead air spaces are entirely avoided. Perfectly uniiorm cooling of the entire food storage chamber and all of its contents at a minimum of cost results.

The arrangement of piping for conveying the compressed fluid to the evaporator is shown in the diagram, Fig. 13. In normal refrigerating operation the compressed fluid leaves the compressor cylinders to a manifold |44 and from there goes through a pipe |43 past a three-way valve |42, and through a pipe |4| into the condenser 90. From the condenser 90 the liquid fluid goes through pipe |40 to receiving tank |39. From receiving tank |39 a pipe |38 passes through the separating wall 36 and to and through a dehydrator |31. From the dehydrator |31 the liquid fluid passes through a pipe |36 and an expansion l valve |35 and enters the manifold head |34, from held in contact with suction gas return pipe |26,

Figs. 1 and 13. Gas pressure from thermostat ,|45 goes through tube |46 to expansion valve |35 and regulates the rate'of flow of fluid toand through the evaporator heat exchanger |23.

The above is a standard and usual circuit for carrying out the refrigerating cycle.

For effecting heating of the heat exchanger |23 for defrosting and transferring heat to the compartment by the same air-moving means as circulates that air from the compartment through the heat exchanger for withdrawing heat, I have provided the following simple arrangement.

The valve |42 may be an ordinary three-way valve in a casing to which opens a pipe |49, Fig. 13. This valve |42 is provided with stem M1 and hand-piece |49 extending below the bottom wall of the front part of the casing I9 to a position where it-can be conveniently operated by the truck driver, as shown in Fig. l. This handpiece is employed for the purpose of shifting the three-way valve to either of two positions. For

the retrigerating cycle it will close communicacondenser 95. In its second position it will open communication to pipe |49 through which the hot gas from the compressor will go through manifold |55 to the coils of the evaporator heat exchanger, irom which the hot gas is returned to manifold |21, Fig. l. and goes through pipe I2 and manifold 11' back to the compressor. v 1

Assho'wn in Fig. 13, this is the shortest direct route, and by-passes the parts connected with pipe |45, although still connected with condenser 95, passing the hot gas through the evaporator heat exchanger |23 where its heat maydo useiul work either in melting the frost on the coils to eect deirosting, or in being transferred by the air circulating means to the compartment to warm the same.

In the 'operation above described for vthe normal cooling cycle the evaporator is a cooling heat exchanger and the condenser a heat exchanger for giving ofi heat and dissipating it to Vatmosphere. That is, the air drawn through the evaporator heat exchanger by the blower back of it is cooled air and coolsthe compartment. In the reverse operation the air travelling as above described, drawn through the evaporator heat exchanger by the blower 92, will be heated air, which, if driven into the compartment for any considerable time, of course, would result in heatinar it.

When the direction of now is at last described Vi'r, may after the evaporator has been used for is to permit evaporation to maintain a humid* atmosphere within the food storage compartment 95. As shown in Fig. l1, a series of lopenings |55 in rear casing wall 45 leads to the space |55 above the rear part oi pan |I. 4In practice masses of capillary material. such' as mineral wool, indicated at |51 of Fig. 12v, Will b Dui; in pan |5| both to increase the evaporating lsurface in the pa-n and to hold the water'therein against any substantial .movement due to the operation of the truck. By these means the return air from vthe food Storage compartment will take up moisture from the large exposed surface in pan |5| with the result that the interior of the food storage compartment will have an atmosphere substantially moisture-saturated, which is of great value in transporting certain types of food stuns, such as meats, vegetables, fruits and the like.-

From gas tank 93 gasoline is fed to carburetor 15 in a customary manner. The carburetor, however, is adaptedto be held in one or the other of two positions -for developing two speeds of the engine, an idling speed, which eile'cts practically no compressing action when cooling is not required, and a high speed for compressing and cooling. The means for eilecting this operation are shown in detail in Figs. l, 13, 14, 15 and 16. These means are as follows:

The cover 25| is removably held in position by positions of less or greater distancel from magnet |13, whereby'the force of the magnet upon armature |12 may be correspondingly varied.-

From the above description the operation of the construction may be understood as follows:

The carburetor is fed inv a well-known way by a tube 2|5 extending from the gas tank 53 to the oat chamber 2| l, Under normal conditions when the air conditioning mechanism is iirst set in operation the interior of the food compartment will be relatively warm. so that the iluid pressure responsive .member |53 'will be contracted -to bring armature |12 within the operative force of magnet |13. This results in putting the carburetor throttlein its position to operate the engine at desired compressing speed,

and takes place when the temperature within thev food storage chamber is above the desired minimum.

As the temperature falls the gas in expansion thermostat |55 will contract. and gas pressure4 The arm |11 is connected at its end through a to rock the frame on the pivot |69 and correspondingly rock arm |11, tending to close the throttle. As the closing of the throttle continues the speed of the gas engine will progressively decrease, having less and less compressing and cooling effect as the temperature within the food storage chamber 96 progressively falls. And when this temperature reaches the desired minimum the spring |92 will have rocked frame |10 and lever |11 and have operated the throttle to a point at or substantially at the limit of predetemxined possible movement of arm |14 alone guide pin y |15, putting the motor into merely idling speed.

-partment the fluid in expansion thermostat |58 will expand and put increased pressure in chamber |60, which will result in contracting or compressing theud pressure responsive member |63 to cause it to move frame |10 and connected levers |1| and |11, first to bringthe armature |12 nearer to the magnet |13 and then, if the temperature rise has been sufficient, to bring the armature to a point` where the pull of the magnet snaps the arm |1| against the end of adjusting screw 203. This again will move the throttle to eiiect full speed of the motor.

It will be noted that the fluid pressure responsive member |58 is located directly in front and toward the bottom of the opening 49 leading from food-storage chamber 96 into the inner chamber 46 of the casing and toward the bottom thereof thus being directly within the stream of return air goingto the evaporator cooling coils. The temperature control of operation of the motor is therefore based upon temperature of return air, which is substantially the warmest air within the food storage compartment. This in- 10 for causing cooling and circulating of the cooled air therein.

Fourth, my invention provides means for distributing the cold air within the compartment wherein an envelope of said cooled air is caused to move along all walls of the food storage chamber and the return of air to the unit is taken from within and toward the top cf this surrounding envelope, thus at all times withdrawing the -warmest air from within the compartment and effectively preventing any pocketing, dead air spaces, or regions of insuilicient cooling.

Fifth, a highly important and novel control of the motor is effected by means of an'expansion thermostat exposed to the return current o! air whereby the carburetor is actuated to effect operation of the motor at a low or idling speed at which the fans or blowers will be suiiiciently operated to maintain movement of air in and from both chambers yof the cooling unit at lreduced rates of movement, and whereby the motor is operated at a higher speed producing rapid movement of air in and from the unit chambers and thus effecting suitably rapid cooling where that is called for.

sures not only a uniform operation of temperao ture shifts but also that the temperature shifts are based upon the warmest air within the food storage compartment and hence cannot leave unduly warm portions of air Within the food storage compartment at any place or any time during the operation of the device.

The advantagesy of my invention have been other chamber contains the evaporator heat exchanger, that is, the means for withdrawing heat from the compartment, In both chambers there are independent air moving means, that in the front chamber for forcing the withdrawn heat out of the system and that in the rear chamber for drawing the air through the evaporator heat exchanger and forcing the cooled air into and through the food storage chamber.

Third, the casing is mounted in the front wall of the food storage compartment, such as is found in a truck or trailer at the top thereof, with the heat-releasing chamber outside where its numerous openings permit quick discharge of all released heat to atmosphere, and with its cooling chamber entirely inside the food compartment Sixth, simple hand operative means is provided for changing flow of hot gas from the compressor to and through the heat-exchanger by means of a shortened circuit for the main stream of gas, which still is connected with the condenser. This shortened circuit otherwise bypasses the receiving tank, expansion valve and `'dehydraton and goes directly to and through the heat-exchanger and back to the compressor. What was the evaporator heat exchanger thus becomes 'a heating heat exchanger which can heat the air going through it to warm the compartment, or can merely melt ice on the heat exchanger for defrosting, the water from such defrosting going to a pan preferably containing rock wool or other material so the air drawn over it by the blower-will take up the water and keep a high degree of humidity in all the air in the compartment.

A nnal and vvery material advantage of my invention resides in the fact that it is both relatively cheap to constructand install, is operated economically and maintains itself in operation with a minimum of adjustment and repair. l

1. In combination with a food storage compartment such as the compartment of a transport vehicle having walls lexposed to outside atmosphere, including a front wall having an opening therethrough,fa cooling unit comprising a single unitary casing the walls of which form two chambers, an evaporator heat exchanger secured to the casing in one chamber, lair moving means in said one chamber, a compressor and air-moving means and a gas engine for operating the compressor and both air-moving means secured to the casing in the other chamber, the casing of the evaporator-containing chamber and said opening being relatively of a shape and size such that said casing part may t inside and be projected through the opening to. be within the compartment and the other chamber be outside the compartment and its walls exposed to outside air, means in the casing vsupporting the iirst mentioned air moving means and forming the dividing partition of said chambers for insulating them one from the other, and means for se- 1l and all parts of the cooling unit may be readily removed therefrom as an entirety.

2. In combination with a food storage corri-- partment such as the compartment of a transport vehiclelxavingwalls exposed to outside atmosphere including a front wall having an opening therethrough, a cooling unit comprising a single unitary casing the walls of which form two chambers, an evaporator heat exchanger secured to the casing in one chamber, air moving means in said one chamber, a compressor and air-moving means secured to the casingin the other chamber, a gas engine secured? to the casing in said last-named chamber i'or operating the com presser and both air-moving means, the casing of the evaporator-containing chamber and said opening being relatively of a shape and size such that said casing part may lit inside and be proiecte'd through the opening to be within the compartment andthe other chamber be outside the compartment and exposed to outside air, means supporting the rst mentioned air moving s'aid chambers for insulating them one from the other. means ior securing said casing, and parts carried'thereby on said iront wall so that the casing as an entirety may be readily Vremoved therefrom, and means on the casingv portion within the compartment controlled by the temperature therein for controlling operation vof the gas engine according to the temperature change demanda made ,upon the instrumentalities operated by the gas engine.

chamber 'having said evaporator therein 'and' 12 to be projected through said opening so that said smaller chamber may be within the compartment and the larger chamber outside the com partment and its walls exposed to outside. air,

. means in the casing supporting the rst mentioned air moving means and forming the dividing'partition 0fV said chambers for insulating them one Vfrom theother, and means for securing said casing and parts carried thereby on said iront wall so that the casing 'as an entirety and all parts of the cooling unit may be readily removed therefrom as an entirety.

4. Means for air-conditioning a closed compartment such as the compartment of a transport vehicle, said means comprising a casing, refrigerating apparatus therein including an-evaporator, part of said casing including an encased having an air inlet opening and an air outlet opening, means for causing a current of air to be conditioned to move through said inlet. across said evaporator and discharging it `through said 'means and forming the dividing partition oi 3. In combination with' a' food storage com- `V partment such as thevcompartment of a transport vehicle having walls exposed to'outsideatmosphere, including a i'ront wall having an opening therethrough, a cooling unitvcomprising a single unitary -casing the walls of which form two chambers. one oi' said chambers being larger in emes-sectional area than the other with part of its walls at the point of junction with the walls o! the smaller chamber extending voutwardly therefrom, aneevaporator heat exchanger secured to the casing inthe smaller chamber, air moving means in said smaller chamber, a compressor and air-moving means and a gasenglne for operating the compressor and-both air-moving means secured to the casing in the larger chamber, the construction of the casing adapting the part thereof enclosing the smaller chamber outlet, a Sas engine mounted in the casing for operating said refrigerating apparatus and said air moving means, an expansion thermostat p0- sitioned to be traversed by said current at the air inlet opening, means for controlling operation of said gas engine. and means caused to b'e operated by said expansion thermostat for causing said controlling means to effect control of operation of the gas engine in response to changes of temperature of said current-'of air.

'FREDERICK M. JONES.

REFERENCES orren- The following referencesare of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,943,965 Hulse v Jan.=16, 1934 2,056,353 Heinz Oct. 6, 1936 2,162,152 Wulle v June 13, 1939 2,180,915 Stebbinst@ N0v.'21, 1939 2,206,631 Clark July 2, 1940 2,229,220 Parks Jan. 21,r 1941 2,231,069 VHarris Feb. 11, 1941 2,257,221 Bell Sept. 20, 1941 2,263,476 Sunday Nov. 18, 1941 2,266,187