US3138939A - Air cooling system for below freezing temperatures - Google Patents

Description

June 30, 1964 A. R. DAVIDSON ETAL BELOW FREEZING TEMPERATURES 8 Sheets-Sheet l Wan so? J1. JUL

INVENTORS Robert K. McCormock 8 y Arthur R. Davidson ATTORNEYS June 30, 1964 A. R. DAVIDSON ETAL- 3,133,939

AIR COOLING SYSTEM FOR BELOW FREEZI Filed March 5, 1962 NG TEMPERATURES 8 Sheets-Sheet 2 t f 36 36 k g, A 5 H 3+ r- TI 3 BY FIG.3.

+ I INVENTORS 5 '1 Robert K.McCor mock 8 E m Arthur R. Duvldson n 1964 A. R. DAVIDSON ETAL 3,138,939

AIR COOLING SYSTEM FOR BELOW FREEZING TEMPERATURES Filed March 5, 1962 8 Sheets-Sheet 3 F lG.4.

IN VENTORS Robert K. McCormock 8 Fl G 5 Arthur R. Davidson ATTORNEYS J1me 1964 A. R. DAVIDSON ETAL 3,138,939

AIR COOLING SYSTEM FOR BELOW FREEZING TEMPERATURES Filed March 5, 1962 s Sheets-Sheet 4 I I I I38 l2 M 32 I38 I I. I F '56 I I66 0 74 :.-d W

ll 5Q r 4o 64- o Z Z [O0 I I 54'' 12 I 5% 8+ Q I I /66 I I i \k FIG.6.

INVENTORS Robert K. McCormock 8 Arthur R. Davidson ATTORNEYS m 1964 A. R. DAVIDSON ETAL 3,138,939

AIR COOLING SYSTEM FOR BELOW FREEZING TEMPERATURES Filed March 5, 1962 8 Sheets-Sheet 5 FIG INVENTORS Robert K.McCormack a Arthur R. Davidson TTORNEYS June 30, 1964 A. R. DAVIDSON ETAL 3,133,939

AIR COOLING SYSTEM FOR BELOW FREEZING TEMPERATURES Filed March 5, 1962 8 Sheets-Sheet 6 FIG.8.

INVENTORS Robert K. Mccormucka Arthur R. Davidson ATTORNEYS June 1964 A. R. DAVIDSON ETAL 3,

AIR COOLING SYSTEM FOR BELOW FREEZING TEMPERATURES Filed March 5, 1962 8 Sheets-Sheet 7 w. I L/ 1 I38", nu! 10 K I l g I24 I00 I 62- t I I 000 72 INVENTORS Robert K. McCormcck & Arthur R. Davidson W KW ATTORNEYS June 30, 1964 A. R. DAVIDSON ETAL 3,138,939

AIR COOLING SYSTEM FOR BELOW FREEZING TEMPERATURES Filed March 5, 1962 8 Sheets-Sheet 8 EVAPORATOR EVAPORATOR SER SURGE RECEIVE R INTERCOOLER 78 SUCTION TRAP nos ORIFIGE TWO STAGE COMPRESSOR INVENTORS Robert K.McCormuck& FIG. IO. Arthur R. Davidson ATTORNEYS United States Patent 7 3,138,939 AIR COOLING SYSTEM FOR BELOW FREEZING TEMPERATURES Arthur R. Davidson, American Falls, Idaho, and Robert K. McCormack, Lake Oswego, Oreg., assignors to Lamb-Weston, Inc., a corporation of Oregon Filed Mar. 5, 1962, Ser. No. 177,525 7 Claims. (Cl; 62-155) Our present invention comprises means for maintaining the interior of a large, single space, insulated structure at below freezing temperatures, such as a food storage warehouse maintained at minus F. The present invention comprises the use of a plurality of self-contained air cooling units totally enclosed within the refrigerated space, with no connections to the exterior of the structure other than power supply lines and water lines. The air cooling units preferably comprise two-stage hermetically sealed compressors adapted to use Freon-22 or other suitable refrigerants as the refrigerating medium. Hence basically the invention is directed to a novel assembly wherein selfcontained, preassembled, automatic and interchangeable refrigeration systems are utilized in multiples to produce a total refrigerating effect required for a single controlled climate space. Such function is obtained by the use of compressor-condenser packages which are so interiorly heated, or sufficiently insulated, or both, to permit their operation in refrigerated spaces maintained at even very low temperatures.

Thus, a principal object of the present invention is to provide a system of the foregoing character comprising a plurality of individual air cooling units each comprising a refrigeration system including a water-cooled condenser, the Water-cooled condensers of all of said units being connected in parallel to common water supply and water return lines whereby a constant flow of water is maintained in said common lines so as to minimize the amount of insulation or heating required to prevent freezing of the common lines.

An additional object of the invention is to provide an inexpensive low temperature freezing system capable of being maintained at low cost, there being no necessity for operators, there being no central engine room, and the system being entirely automatic in its operation. In this respect, although the system is ideally suited for low temperature maintenance of the order indicated (-5 F.) any temperatures below ambient temperature, as from Well below freezing to moderate temperatures (as, e.g. 40 F.) may be maintained at a predetermined constant through use of the instant invention.

A further objective of theinvention is to provide large tonnage capacities in refrigeration systems by the use of a plurality of self-contained air cooling units which permit precharging of refrigerant, thus eliminating the necessity of expensive installation and maintenance of lengthy refrigeration systems extending from a central engine room to zone cooling units.

Another objective of the invention is the provision of means for operating compressor-condenser systems within the confines of a given refrigerated space with the components thereof arranged in such manner as to prevent freeze up or damage during operation or shutdown of the system.

A furtherobject of the invention is to provide a system of the foregoing character eliminating the fabrication and installation of air supply and return ducts.

An additional object of the invention is to provide large tonnage air cooling systems in a manner permitting factory assembly of all components except water and electrical components, thereby materially reducing the cost of installation and maintenance and assuring trouble-free performance of the system.

3,138,939 Patented June 30., 1964 Another object of the invention is to provide means of the character outlined in the foregoing by which defrosting is accomplished while maintaining the space temperature at the desired level.

A further objective of the invention is to provide means of the foregoing character in which defrosting is automatically and effectively controlled.

Another object of the invention is to provide air cooling units for use in such a system in which defrosting is preferably accomplished by the use of hot gas in the refrigerating system, although other defrosting methods are also applicable, such as water defrosting, electric defrosting, etc.

An additional object of the invention is to provide means of the foregoing character in which a plurality of separate air cooling units are employed, permitting a unit failure to be corrected without losing stored materials due to spoilage as a result of mechanical failures.

These and other objects and advantages of the invention may be more readily understood by reference to the following specification taken in connection with the accompanying drawings, wherein like numerals refer to like parts throughout, and in which a preferred embodiment of the invention is illustrated and described.

In the drawings,

FIGURE 1 is a schematic plan view of a portion of the interior of a large building incorporating the inventron;

FIGURE 2 is a partial cross-section through a building such as illustrated in FIGURE 1, the view being on an enlarged scale and taken substantially from line 22 of FIGURE 1;

FIGURE 3 is a plan view of an individual unit taken substantially from the line 33 of FIGURE 2;

FIGURE 4 is a side elevation taken substantially from the line 44 of FIGURE 3;

FIGURE 5 is an opposite side elevation taken substantially from the line 55 of FIGURE 3;

FIGURE 6 is a horizontal section, on an enlarged scale, through one of the refrigerating units taken substantially along line 66 of FIGURE 8;

FIGURE 7 is a plan view of one of the air cooling units taken substantially along line 77 of FIGURE 8;

FIGURE 8 is a vertical section through one of the air cooling units taken substantially along line 88 of FIG- 7 URE 6;

FIGURE 9 is a vertical section through one of the air cooling units taken substantially along line 9--9 of FIG- URE 6; and

FIGURE 10 is a schematic disclosure of the refrigerating system of an individual unit.

The present invention is illustrated in association with a low-temperature storage structure 1ft preferably comprising a large rectangular, single space, insulated structure including a side wall 12, an opposite side wall 14, an end Wall 16 and an opposite end wall (not shown) One or more of the walls may be provided with access doors 18 and one or more of the walls may be associated with insulated vestibules 20 for permitting the entry and exit of loaded vehicles. The structure necessarily includes a floor 22 on which there are no substantial obstructions other than stored products. An insulated roof 24 is supported entirely by transverse trusses 26 extending from side to side of the structure so that only an upper part of the interior space contains building elements, whereby vehicles may freely traverse the entire interior of the building and piles of material may be placed in any position on the floor and extend up to the lower edges of the trusses. It is to be appreciated that the present invention may be incorporated in structures having different outlines and in which there may be inter- J ior columns, the requisite of the structure being that it encloses a large interior space.

The interior space is cooled in accordance with the present invention by a plurality of self-contained air cooling units 30, each individually mounted closely beneath the roof 24, preferably midway between adjacent trusses 26 and with their lower portions above the lower beams of the trusses. In this respect it is to be noted that although the cooling units herein specifically described involve the use of water cooled condensers, evaporative or air cooled condensers are equally suitable for use in the inventive combination. At any rate, such cooling units are preferably suspended, such as by means of rods 32 suitably fastened at their lower ends, to angle bars 34 forming the corner edges of the frames of the units, the upper ends of the rods extending through longitudinal beams 36 extending between the trusses adjacent the roof 24. The units are preferably arranged in a single row extending across the building from one wall to the other along or closely adjacent a median line of the building. Depending upon the load imposed upon the units and their capacity, there may be a unit in each space between each adjacent pair of trusses, or there may be a gap here and there, provided that sufficient refrigeration capacity is present to take care of the load in the event that one, or possibly two, of the units should be temporarily shut down due to mechanical failure.

Access to the units is provided by means of a catwalk 38 extending alongside the entire row of units, at a level such that access doors 40 of the units may be opened to permit entry ito each unit, the access doors preferably facing the catwalk. Adjacent each unit there is preferably provided a short ladder 42 leading to an elevated catwalk 44 partially surrounding the unit whereby access to the upper portion of the unit may be had. A stairway 46 leads from the roof of the central vestibule to the catwalk 38 and a ladder 47 leads from there to the floor.

Suspended beneath the catwalk 38 there is provided a common condenser water supply pipe 50, a common condenser water return pipe 52 and a common condensate drain pipe 54, all of which are appropriately insulated and run the length of the catwalk. A common electric wire conduit 56 is suspended adjacent the roof and runs alongside the row of units. The water supply and return pipes, the condensate pipe and the wiring in the electrical conduit are the only connections of the system which run outside of the building, through the wall 16.

Each air cooling unit comprises an insulated compartment having opposite side walls 60 and 62, a rear wall 64, a front wall 66 in which the door is located, a bottom wall 68 and a top wall 70, all of which contain sufiicient insulation to maintain the temperature within the compartment at a comfortable working temperature above freezing. In this respect it is to be understood that the invention contemplates any means of heating the compressor-condenser package contained within the described compartment, as by insulation thereof, or any other means of heating these components such as to permit operation thereof directly within the confines of the refrigerated space.

In any event, each air cooling unit comprises a low temperature refrigeration system including a compressor portion 72, a condenser portion 74 and an evaporator portion 76 connected together in refrigerant flow relationship, with the compressor portion and the condenser portion within the insulated compartment and the evaporator portion located outside of and preferably on top of comprises a hermetically sealed, suction gas cooled, twothe compartment. The compressor portion preferably stage compressor 78 mounted on the floor of the compartment. Although the invention is not necessarily confined to this type of compressor, it is stated as preferable as representing a type which prevents transfer of motor efiiciency heat loss from the motor to the confined space housing this compressor-motor combination. Similarly, although a two-stage compression system is indicated as preferred, single-stage units may be desired under certain circumstances.

The condenser portion preferably comprises an intercooler 80, a surge receiver 82, a suction trap 84, and a water cooled condenser 86, all of which are mounted upon or near the compressor. Although a single evaporator may be utilized under certain circumstances, the evaporator portion 76 preferably comprises a pair of evaporators 88 and 90 connected in parallel in the system, one being mounted above the front of the compartment and the other being mounted above the rear of the compartment, with a space therebetween. Each evaporator is enclosed within a sheet metal wrap 92 which is open toward the center of the unit and which mounts a pair of air impelling units Q4 adapted to draw air through the evaporator from the space above the unit and the central space between the coils and impel the cooled air leaving the evaporators horizontally through the upper part of the building space in opposite directions, one stream being directed toward the side wall. 12 and the other stream toward the side wall 14, as indicated in the arrows in FIGURE 1. Preferably the space between the evaporators is provided with side walls as indicated at 95, so that air is drawn into the evaporators from the uppermost part of the refrigerated space. The cold air which is openly projected toward the side walls of the space comingles with the air within the space, the resulting colder portions thereof falling toward the floor and the warmer portions thereof rising toward the ceiling to be recirculated through the evaporators. Other obvious fan or blower arrangements may be used: the air impellers may be arranged for discharge in one direction only, or attached to appropriate ductwork, or positioned for air travel vertically up or down, etc. At any rate, each evaporator preferably sits in a condensate pan 97 from which a condensate drain line 98 extends downward into the interior of the compartment and then laterally through the wall of the compartment to join the common condensate pipe 54. However, other means of collecting defrost condensate may be desirable: condensate containers may be arranged within the refrigerated space for periodic removal, the condensate becoming frozen and recovered as ice or snow. Condensate may also either be pumped back into the condenser water mains or re-evaporated back into the refrigerated space by either a source of heat or a humidifying nozzle.

As herein depicted the referred to air cooling units are shown as preferably extending along the upper center line of the refrigerated space. However, such multiple units can be optionally positioned along the end or side walls of the building. Alternatively, the units may be arranged in rows running the short dimension of the building, there being a sufficient number of units in any event to meet the required cooling load. The system also lends itself to arrangements wherein the cooling units may be mounted upon appropriate conveyances whereby they are rendered completely portable in such instance having appropriate temporary water and power connections. Or on the other hand, the individual cooling units may be mounted in doorway or appropriate wall openings, in which cases air from an air cooled condenser is easily discharged to the outside, while refrigerated air is discharged to the interior of the structure, where separate, individual units are so used, factory assembly and prepackaging thereof for immediate use without cumbersome installation procedures renders the use of same most advantageous.

The refrigerating system is schematically indicated in FIGURE 10, in which the directional signs on the pipes indicate refrigerant flow during normal flow of cooling refrigerant to the two evaporators 88 and 90 and return to the compressor 78, and the directional arrows beside the pipes indicate refrigerant flow during the time that the evaporator 90 is being defrosted. It is to be appreciated that the refrigerant flow during the time that the other evaporator 88 is being defrosted would correspond.

The expanded refrigerant gas enters the compressor 78 through a suction line 100 connected to the low pressure cylinders or first stage part 102 of the compressor. The hot gas under the first stage of compression passes through passageways schematically indicated at 104 into the high pressure cylinders or second stage part 106 of the compressor. The highly compressed gas is then conducted by discharge line 108 into the top of the shell of the water cooled condenser 86 through a spring-loaded check valve 110. The liquefied refrigerant is then drawn through pipe 112 into the internal coils of the heat intercooler 80. A large branch of the pipe 112, indicated at 114, leads to the bottom of the surge receiver 82. A small branch 116 of the pipe 112 leads to the shell of the intercooler through a solenoid valve 118 and an expansion valve 120 controlled by a thermal bulb 122 mounted on the pipe 104, whereby a portion of the liquid refrigerant is drawn off and expanded in the shell of the intercooler 80 to subcool the liquid in the pipe 112. The expanded gas is drawn back from the intercooler into the passage 104 through a connecting pipe 124. The solenoid valve 118 is constantly open when the compressor is in operation.

The subcooled liquid is discharged from the intercooler through pipe 126 into a header having a branch 128 leading to evaporator 90 and a branch 130 leading to evaporator 88. The flow through pipe 128 is controlled by a normally open solenoid valve 132 and an expansion valve 134 having a sensing bulb 136 on a branch return line 138. The flow through branch 130 is controlled by a normally open solenoid valve 139 and an expansion valve 140 having a sensing bulb 142 on a branch return line 144. The branch return lines 138 and 144 join a return line 146 which enters the suction trap 84. Gas from the suction trap 84 is drawn off through the suction pipe 100. Liquid from the suction trap 84 passes through a pipe 150 controlled by a solenoid valve 152 and having a fixed orifice 154 therein. The solenoid valve 152 is open whenever the compressor is running.

Hot condensed gas may be drawn from the discharge line 108 through a pipe 156 having a branch 160 leading into the evaporator 90 and through the tubes therein which ordinarily carry expanding refrigerant, and a branch 162 leading to the evaporator 88 and through the tubes therein which ordinarily carry expanding refrigerant. Pipe 160 is normally blocked by a solenoid valve 164 and pipe 162 is normally blocked by a solenoid valve 166. Another pair of normally open solenoid valves 168 and 170, are adapted to shut branch suction pipes 138 and 144 respectively. Solenoid valves 132, 164 and 168 act in unison so that when defrost gas is desired in evaporator 90, solenoid valve 132 is closed, solenoid valve 164 is opened, and solenoid valve 168 is closed. Likewise, solenoid valves 139, 166 and 170 act in unison so that when defrost gas is desired in evaporator 88, solenoid valve 139 is closed, solenoid valve 166 is opened, and solenoid valve 170 is closed. In the illustrations of the defrost cycle by means of the arrows set at the sides of the pipes, defrosting gas is flowing through evaporator 90 andrefrigerating liquid is flowing into and expanding in evaporator 88.

Under the foregoing circumstances the evaporator 90 is acting as a partial condenser, and hot liquid and gas are flowing through pipe 138 into a pipe 172 which joins a header 174 through a spring loaded check valve 176. The header 174 discharge liquid refrigerant into the surge receiver 82 through a connection 178, and gaseous refrigerant into the condenser 86 through a connection 180. While this is going on, refrigerating liquid is still 'flowing into evaporator 88, from which expanded gas is possible within the purview of the invention.

being returned to the compressor. Similarly, when defrosting gas is flowing through evaporator 88 refrigerat ing liquid is flowing in the normal fashion into evaporator 90. In this instance refrigerant is returned from evaporator 88 through a pipe 173 and spring loaded check valve 177 into header 174. Through the interconnections provided there is always a supply of sufiicient gas to the compressor to feed liquid refrigerant to one or the other, or both, of the evaporators, and when required, simultaneously to feed hot compressed refrigerant to one of the evaporators for defrosting purposes and liquefied refrigerant to the other for cooling purposes.

Mounted within the zone of cooling influence of each air cooling unit there is a temperature sensing means such as a thermostat 184 preferably located within the stream of air entering the space between the evaporators 88 and 90, so as to sense the temperature of the air influenced by the particular unit as a whole and to control the on-oif cycling of that unit accordingly. The thermostat 184 is electrically connected to the motor of compresor 78 and the solenoid valves 118 and 152 so that whenever the compressor operates the valves 118 and 152 are open, and whenever the compressor stops the two valves are closed.

Electric clock timing means 186 is provided in association with each unit so that evaporator 88 is periodically defrosted for a short period of time while evaporator continues to act as an air cooler. Preferably there is one timing means 186 controlling all units sequentially so that no more than one or possibly two of the entire series of evaporators is being defrosted at any one time, although it is to be understood that other methods of automatically preparing the defrost cycle, and without the use of time clocks and solenoid valves, may be utilized. The arrangements of pipes and check valves, and the solenoid valves 132, 139, 164, 166, 168 and constitute defrosting means to shut off the flow of liquefied refrigerant to either of the evaporators 88 and 90 for defrosting purposes while the flow of liquefied refrigerant to the other of said evaporators continues. Each defrosting action is so timed as to completely clear the particular coil of frost once every certain number of hours.

In the event of mechanical failure of any one unit, the remainder of the units will carry the load until repairs, or replacement of an entire unit, may be effected.

Associated with each air cooling unit are branch water pipes, a branch water supply pipe 190 leading water from the common supply pipe 50 to the water cooled condenser 86 and a branch water return pipe 192 returning the water to the common return pipe 52. -Valve and bypass means comprising a three-way, modulating, pressure actuated water valve 194 and a bypass pipe 196 keep the flow of water in pipes 190 and 192 constant. As the presure in the condenser rises, the amount of water bypassed through pipe 196 falls and the amount of water permitted to enter the condenser rises, and vice versa. Therefore, the supply through the common pipes is constant at all times, protecting the water supply and return system from freezing.

While we have herein shown and described the defrosting cycle as being accomplished by hot refrigerant, it is to be appreciated that the present invention may utilize or be supplemented by any other means of defrosting, such as electrical heating coils, water defrosting and the like. Also, while we have herein shown and described a hermetically sealed two-stage compressor, it is to be appreciated that the invention contemplates the use of any other type of compressor capable of pro ducing low temperatures in the cooling surfaces.

It should be apparent to those skilled in the art that many other modifications in arrangement and detail are For example: where air cooled, each air cooling unit is so arranged as to permit only the evaporator portion thereof to project below the roof line, with the compressor-condenser portion extending above the evaporator and above the roof line. Such not only facilitates the use of air cooled condensers, but also conserves space within the refrigerated structure. Obviously, the arrangement may be such that individual evaporators are arranged on either one side or the other of the compressor-condenser compartment, instead above or beneath the same, thus reducing the over-all height of such air cooling unit.

In addition the assembly is conducive to the use of cooling towers which can be utilized in conjunction with such air cooling units. In such event the condenser water lines are run vertically between the air cooling unit and the cooling tower thereabove, thus eliminating the necessity of running water piping the length of the room. This also permits collection of defrost water condensate within the heated compressor-condenser enclosure, said condensate being pumped through the condenser Water pump, also located in the heated enclosure, from whence it passes through the condenser for return to the cooling tower. Thus, such defrost condensate water may be used as a source of make up water to the cooling tower, providing the latter not only with cooler water but with distilled water as well.

From the foregoing explanation it will be understood that the basic concept of this invention permits installation of all the complete refrigeration system components within the confines of the cold room space. The equipment can, in the described manner, be successfully operated under the conditions of temperature and/ or humidity found in different sizes and types of cold storage rooms. By first enclosing the compression and condensin-g equipment within a heated compartment the assembly of the invention can function satisfactorily despite external lowered temperatures; further, by using hermetically sealed compressors the friction heat of the drive motors is transmitted to the refrigerant suction gas, instead of to the surrounding space. The several advantages of such a novel arrangement are manifest: by rendering these relatively small refrigeration systems automatic in operation, the operating engineering staff is substantially reduced and additional facilities such as engine rooms adjacent to the cold storage room, or long piping runs to such engine rooms, are eliminated. Furthermore, existing facilities can be expanded by the use of the instant assembly without the necessity of enlargement of the then in place, already operating refrigeration system.

All such modifications as the foregoing, as well as others which come within the true spirit and scope of the following claims, are considered to be a part of our invention.

We claim:

1. An air cooling system for maintaining the interior of a single space, insulated structure at below freezing temperatures, comprising a plurality of self-contained air cooling units mounted in the upper part of said space, each of said units comprising an insulated compartment and having a low temperature refrigeration system including a compressor portion, a condenser portion and an evaporator portion connected together in refrigerant flow relationship, expansion means, said compressor portion and said condenser portion being within said compartment and said evaporator portion being outside of said compartment, said condenser portion comprising a watercooled condenser, said evaporator portion comprising a pair of air cooling evaporators connected in parallel in said refrigeration system, and said refrigeration system having defrosting means to shut off the flow of liquefied refrigerant to either of said evaporators for defrosting purposes while permitting the flow of liquefied refrigerant to the other of said evaporators to continue, air propelling means arranged to cause air from said space to traverse said evaporators and to propel the air leaving said evaporators openly across the upper part of said space, a temperature sensing means responsive to the temperature of air entering the evaporator portion of said unit to control on-off cycling of said unit thereof, a common water supply pipe and a common water return pipe traversing said space, a plurality of branch water supply and branch water return pipes respectively connecting said Water cooled condensers in parallel to said common water supply and common water return pipes, means to maintain the interior of each of said insulated compartments at above freezing temperatures, and timing means periodically actuating said defrosting means of said unit sequentially.

2. The structure set forth in claim 1 wherein said defrosting means is provided with means to direct hot compressed refrigerant from said compressor portion into an evaporator being defrosted, and means to direct liquefied refrigerant from said condenser portion into the other of said evaporators While one of them is being defrosted.

3. A refrigeration means for maintaining an interior space at below freezing temperatures, comprising a plurality of insulated and heated compartments, a preassembled, automatic and interchangeable refrigeration unit in each of said compartments, each of said units having a low temperature refrigeration system including a compressor portion, a condenser portion and an evaporator portion connected together in refrigerant flow relationship, expansion means, said compressor portion and said condenser portion being within said compartment and said evaporator portion being outside of said compartment, said condenser portion comprising a water cooled condenser, said evaporator portion comprising a pair of air cooling evaporators connected in parallel in said refrigeration system, and said refrigeration system having defrosting means to shut off the flow of liquefied refrigerant to either of said evaporators for defrosting purposes while permitting the flow of liquefied refrigerant to the other of said evaporators to continue, air propelling means arranged to cause air to traverse said evaporators and to propel the air openly therefrom, temperature sensing means responsive to the temperature of air entering said evaporator portion to control on-oif cycling thereof, a Water supply pipe and a water return pipe connected to said Water cooled condenser, valve and bypass means including a three-way, modulating, pressure actuated valve connecting said water supply pipe to said water return pipe for maintaining constant flow of water in said pipes, timing means periodically actuating said defrosting means, and means to maintain the interior of each of said compartments at above freezing temperatures.

4. The structure set forth in claim 7 wherein said defrosting means comprises means to direct hot compressed refrigerant from said compressor portion into an evaporator being defrosted, means to direct liquefied refrigerant from said condenser portion into the other of said evaporators while one of them is being defrosted, and means to receive and temporarily store liquefied refrigerant leaving the evaporator being defrosted.

5. A refrigeration means for maintaining an interior refrigerated space at from below freezing temperatures to below about 40 F. comprising a plurality of removable and insulated compartments positioned in said interior space, means to maintain the interior of each of said compartments at substantially above freezing temperatures, a preassembled, automatic and interchangeable refrigeration unit in each of said compartments, each of said units having a low temperature refrigeration system including a compressor portion and a condenser portion, coolant fluid supply and return means for said condenser portion, expansion means, an evaporator portion connected together in refrigerant flow relationship with said compressor and condenser portions, said compressor portion and said condenser portion being within said compartment and said evaporator portion being outside of said compartment but within said interior refrigerated space, said evaporator portion comprising a pair of evaporators connected in parallel in said refrigeration system,

said refrigeration system having defrosting means to shut 01f the flow of liquefied refrigerant to either of said evaporators for defrosting purposes While permitting the flow of liquefied refrigerant to the other of said evaporators to continue, and air propelling means arranged to cause air to traverse said evaporators and to propel the air openly therefrom into said interior space.

6. A refrigeration means for maintaining an interior refrigerated warehouse space at temperatures from subzero F. to about 32 F. comprising a plurality of removable and insulated compartments positioned in said interior space, means to maintain the interior of each of said compartments at above freezing temperatures, a substantially preassembled, automatic and interchangeable air-cooling unit in each of said compartments, each of said units having a low temperature refrigeration system including a compressor portion and a condenser portion, coolant fluid supply and return means for said condenser portion, expansion means, an evaporator portion connected together in refrigerant flow relationship with said compressor and condenser portions, said compressor portion and said condenser portion being within said compartment and said evaporator portion being outside of said compartment but within said interior refrigerated warehouse space, said evaporator portion comprising an evaporator interconnected with said refrigeration system, said refrigeration system having defrosting means to periodically shut off the How of liquefied refrigerant to said evaporator for defrosting ptnposes, and air propelling means arranged to cause air to traverse said evaporator and to propel the air therefrom into said interior refrigerated warehouse space.

7. A refrigeration means for maintaining an interior refrigerated warehouse space at temperatures from subzero F. to about 32 F. comprising a plurality of substantially preassembled air cooling units located inside the refrigerated Warehouse space, each of said units comprising an insulated compartment portion and an uninsulated portion, said insulated compartment portion containing a refrigeration compressor and a refrigeration condenser, said uninsulated portion containing an evaporator and a fan positioned and adapted to move warehouse air to said evaporator, said evaporator, condenser and compressor being connected together in refrigerant flow relationship, heating means to maintain said insulated compartment above about 32 F., defrosting means to periodically defrost said evaporator, fluid coolant supply and exhaust means for cooling said condenser, drain means for disposing of condensate from said evaporator, control means comprising a thermostatic means responsive to air temperature to maintain said range of said temperatures, and means to automatically time said periodic defrost.

References Cited in the file of this patent UNITED STATES PATENTS 2,254,654 Holmes Sept. 2, 1941 2,286,491 Kucher June 16, 1942 2,496,143 Backstrom Jan. 31, 1950 2,553,623 Zumbro May 22, 1951 2,688,849 Andrews Sept. 14, 1954 2,931,192 Weinberg Apr. 5, 1960 2,944,408 Willis July 12, 1960 2,960,840 Hosken et a1. Nov. 22, 1960 2,968,934 Komedera J an. 24, 1961 2,978,877 Long Apr. 11, 1961 3,050,958 Allender Aug. 28, 1962

Claims (1)

1. 6. A REFRIGERATION MEANS FOR MAINTAINING AN INTERIOR REFRIGERATED WAREHOUSE SPACE AT TEMPERATURES FROM SUBZERO *F. TO ABOUT 32* F. COMPRISING A PLURALITY OF REMOVABLE AND INSULATED COMPARTMENTS POSITIONED IN SAID INTERIOR SPACE, MEANS TO MAINTAIN THE INTERIOR OF EACH OF SAID COMPARTMENTS AT ABOVE FREEZING TEMPERATURES, A SUBSTANTIALLY PREASSEMBLED, AUTOMATIC AND INTERCHANGEABLE AIR-COOLING UNIT IN EACH OF SAID COMPARTMENTS, EACH OF SAID UNITS HAVING A LOW TEMPERATURE REFRIGERATION SYSTEM INCLUDING A COMPRESSOR PORTION AND A CONDENSER PORTION, COOLANT FLUID SUPPLY AND RETURN MEANS FOR SAID CONDENSER PORTION, EXPANSION MEANS, AN EVAPORATOR PORTION CONNECTED TOGETHER IN REFRIGERANT FLOW RELATIONSHIP WITH SAID COMPRESSOR AND CONDENSER PORTIONS, SAID COMPRESSOR PORTION AND SAID CONDENSER PORTION BEING WITHIN SAID COMPARTMENT AND SAID EVAPORATOR PORTION BEING OUTSIDE OF SAID COMPARTMENT BUT WITHIN SAID INTERIOR REFRIGERATED WAREHOUSE SPACE, SAID EVAPORATOR PORTION COMPRISING AN EVAPORATOR INTERCONNECTED WITH SAID REFRIGERATION SYSTEM, SAID REFRIGERATION SYSTEM HAVING DEFROSTING MEANS TO PERIODICALLY SHUT OFF THE FLOW OF LIQUEFIED REFRIGERANT TO SAID EVAPORATOR FOR DEFROSTING PURPOSES, AND AIR PROPELLING MEANS ARRANGED TO CAUSE AIR TO TRAVERSE SAID EVAPORATOR AND TO PROPEL THE AIR THEREFROM INTO SAID INTERIOR REFRIGERATED WAREHOUSE SPACE.

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