US3866435A

US3866435A - Cooling container

Info

Publication number: US3866435A
Application number: US366279A
Authority: US
Inventors: Karl Frank; Martin A Frank; Dieter Tschentscher
Original assignee: Burger Eisenwerke AG
Current assignee: Burger Eisenwerke AG
Priority date: 1972-06-05
Filing date: 1973-06-04
Publication date: 1975-02-18
Anticipated expiration: 1992-02-18
Also published as: DE2227313A1; DE2227313C2

Abstract

A transportable refrigerating container including descending passage means operable to receive a gravity induced flow of coolant gas and having flow controlling aperture means providing individualized, controlled communication between the descending passage means and individual product compartments.

Description

United States Patent 1 1 Frank et a1.

1 Feb. 18, 1975 1 COOLING CONTAINER [75] Inventors: Karl Frank, Linz/Rhine; Martin A.

Frank, Cologne; Dieter Tschentscher, Mayen, all of Germany [73] Assignee: Firma Burger Eisenwerke Aktiengesellschaft, Burg/Dillkreis, Germany Filed: June 4, 1973 Appl. No: 366,279

[30] Foreign Application Priority Data June 5, 1972 Germany 2227313 [52] US. Cl 62/382, 62/388, 62/420, 62/441, 62/457 [51] Int. Cl. F25d 25/02 [58] Field of Search 62/384, 388, 382, 457,

[56] References Cited UNITED STATES PATENTS 1,883,940 10/1932 Killeffer 62/388 1,922,456 8/1933 Powell 1,963,674 6/1934 Pearsons.. 2,325,371 7/1943 Clerc 2,506,448 5/1950 Gregor 62/382 Primary Exunziner-Meyer Perlin Assistant I;'.\'uminerRonald C. Capossela Attorney, Agent, or FirmBurns, Doane, Swecker 8L Mathis [57] ABSTRACT A transportable refrigerating container including descending passage means operable to receive a gravity induced flow of coolant gas and having flow controlling aperture means providing individualized, con trolled communication between the descending passage means and individual product compartments.

17 Claims, 15 Drawing Figures PATENTEQ FEB l 8W5 sum 2 OF 3.

1 COOLING CONTAINER GENERAL BACKGROUND, OBJECTS, AND

SUMMARY OF INVENTION The invention relates to a refrigerating container to keep temperature sensitive products, such as food, pharmaceuticals, chemical products, etc., fresh and cool. Particularly, the invention relates to a transport- I able container having a work space subdivided in several chambers to receive the goods to be refrigerated and a compartment for a gasifying coolant, especially CO in solid form (dry ice). Preferably, this latter compartment is located above said work space.

For keeping temperature sensitive products cool and fresh, movable containers are used today in which the cooling system consists of added consumable coolants. Beside nitrogen and freon, carbon dioxide especially comes into consideration as a consumable coolant here. In gaseous form, carbon dioxide is heavier than air and in solid form at standard atmosphere pressure, in its own gaseous atmosphere has a temperature of 78.5C. This solid CO called dry ice, sublimates, i.e.,

it passes from a solid to a gaseous state, whereby at atmospheric pressure with the gas heating to C of the neighborhood, 152.4 K. cal/kg are withdrawn.

Heretofore, this coolant is placed in the container, in the case of the known containers of the initially mentioned construction, in the form of prismatic slabs (plates) together with the material to be cooled, or it is arranged compactly above or beside the work space. This, however; results in the essential disadvantage that the cooling stream of gas fills the work space in an uncontrolled manner and that the temperature pattern developing in the work space is very uneven, in such a way that at certain places very low temperatures prevail, with the consequence of local freezing of the chilled goods, while at other places no sufficient cooling is assured. These disadvantageous effects occur at an increased degree, when using containers in air traffic, especially during the starting and landing phases of the airplanes which cause considerable inclinations of the containers.

To this it must be added that, particularly in air traffic, very variable ambient conditions may occur. In case ofa modern airport with cold storage, the required quantity of dry ice is added to the filled container which is at a temperature of l2-l 6C upon leaving the cold storage. The quantity of coolant is here dimensioned such that the chilled goods remain chilled until served on the airplane. If, however, there is no cold storage at the airport, then such a quantity of dry ice must be added to the container after it being filled, such that the dry ice will be capable of cooling down the container itself and its contents from ambient temperature to, for example, cold storage temperature and to maintain this temperature of 12l6C until time for serving. From these variable possibilities of use and requirements there result, however, variable refrigerating problems, with which the customary containers cannot cope.

It is the task of the invention, therefore to create a cooling container of the initially mentioned type, in which the cooling stream of gas flows controlled in such a way, that the temperature field pattern in the work space of the container will be as even as possible, even under unfavorable circumstances. as the beginning of cooling, repeated opening of the container door, tipping and sloping movements of the container,etc.

A further task of the invention consists in creating a container which will cope with the stated variable con dition, whereby the degree of filling of the container with chilled goods and possibly also requirements of the chilled goods for variable cooling needs are still superposed as additional conditions.

According to the invention the solutio of these problems is characterized by at least one descending shaft (passage means) branching off from the coolant space, for receiving the developing cooling gas, and from which shaft openings (i.e., apertures), dividing the stream of cooling gas doseably or in segments into partial streams, branch Off into the individual work space compartments.

In the invention one will insure that the cooling stream drops down in a defined direction of flow in the descending shaft by the action of gravity, whereby a partial stream is branched off for each compartment having chilled goods and which can be closed exactly with a branch stream or segment which is adequate with respect to its cooling performance. Detailed experiments have shown that in this manner an even temperature field pattern quickly occurs in the container which is essentially independent of outside influences such as inclinations of the container during take-off of the plane in which the container is located. Beyond that, however, there also is the possibility, if desired, to produce temperature field patterns which are even within themselves but variable among each other, for instance, whenever chilled goods with variable cooling needs are placed in the container.

A further development of the invention concerns a cooling container with inserts arranged in levels one above the other, the topmost level serving for the coolant, especially in a movable container for keeping food in airplanes fresh and cool. Such containers, mostly called trolleys, are developed according to the invention in such a way that the descending coolant gas shaft, preferably extending over the entire height of the container and across one side or end of the device, is limited by an outside wall of said container and by a separating wall essentially parallel to the former, whereby the separating wall has sluice-like openings leading to the insertable levels of the work space.

If this container has only one door, then the descending shaft can be disposed on the container side opposite to the door, and the gap space between the door and insertable shelves can have escape openings for excess air and/or cooling gas, possibly in the form of leaks of the door hinges. In this way one will achieve a particularly exact guidance of the streams of cooling gas and especially the development of an even temperature field at the beginning of cooling will be accelerated, at a time when the container is still filled with air.

In order to ensure that the desired pattern or direction of flow, even in case of greater inclinations of the container, the insertions for the coolant can be slightly slanted toward the horizontal in such a way that it slopes toward the inlet for the descending shaft.

In the case of cooling containers with doors at two opposed sides, the arrangement advantageously is made such that two descending shafts are provided on opposed sides of the container and that at least one of the gap spaces, located between the other two container sides and the insertion levels or goods areas, has escape apertures for excess air and/or cooling gases, possibly in the form of leaks of the door hinges. Further, the descending cooling gas shafts can also be dis posed on both sides of the container, in which case it will be particularly effective to develop the doors on their sides with double walls, and to use the two walls of each door as boundaries for the descending shaft. These containers with descending shafts at opposed sides of the container are particularly insensitive -with regard to the temperature field pattern to inclinations and tippings of the container.

In order to facilitate the controlled, segmented flow or division of the cooling gas stream into partial streams, the apertures in the separating wall or walls can be designed in such a way that they consist of per forations of the separating wall and of guide tongues or baffles assigned to the individual apertures and projecting from the separating wall into the descending coolant gas shaft. Advantageously, the apertures will have widths of passage which are variable among themselves, in such a way that the cross section increases from the topmost to the lowest inserting shelf, whereby the width of passage is determined by the cross section of the aperture and/or the position of the tongue. With that one will achieve that the cooling effect over the entire height of the container will be as even as possible. Nevertheless, it will not be possible to prevent completely, the phenomenon that in the topmost shelf for chilled goods, which is adjacent to the insert with the coolant, the temperature will drop lower, particularly during the period of the start of cooling. This may be desirable in some cases, perhaps whenever edible ice (ice cream) is to be stored in the topmost level. Whenever the same temperature is always wanted in the topmost insertion shelf as exists in the lower shelves below it, then according to the invention, the aperture of the topmost insertion shelffor chilled goods adjacent to the insert for coolants, can be provided with a closing lid and this insertion shelf can have closable apertures leading outside.

It has proved to be particularly effective whenever, in the case ofthe cooling container according to the invention, dry ice in form of a heap of dry ice tablets, little rods or cubes is used as coolant. This form of the dry ice, as compared to the customary solid dry ice slabs, has a considerably larger evaporation surface. This is of particular importance especially for the abovementioned cooling containers in air traffic since, there, mostly only relatively short cooling times are required.

In a further development of the invention, provision is made such that two longitudinally extending walls of a container are developed as guides for the cooling gas in the form, each time, of several flat channels whigih are connected on the one hand with the compartment for the coolant and on the other hand with the work space compartments, located at various horizontal levels, whereby the cross section of passage of the channels is proportional to their length.

In case of this further development therefore, the stream of cooling gas is divided in partial streams and is fed to the individual work space compartment such that the inflowing quantity ofgas is largely independent of inclinations of the longitudinal sides of the container, which are generally pointing in the direction of flight. Since guidance of the cooling gas takes place at both longitudinal sides, the stream of cooling gas must pass through relatively short paths in order to fill the space between two adjacent goods levels, i.e., the coolant space for one goods area.

In order to adapt the cooling effect furthermore to the various conditions on the airport, the insertion of the coolant is developed especially according to the invention as hereinafter described and claimed. Especially, insertion of the coolant is subdivided into shelves, which house the quantity of coolant required for the pertinent cooling task, whereby a heap of small dry ice rods is used advantageously, since such a heap has a larger surface than the dry ice slabs of the same weight and thus the quantity of cooling gas sublimated in the unit of time is larger.

DRAWINGS In the drawings, embodiments of the invention are shown by way of example, namely:

FIG. 1 shows a cooling container in longitudinal section; FIG. 2 is a perspective. fragmentary view of a separating wall of the FIG. 1 container showing sluice openings;

FIG. 3 is an end view ofa separating wall of the FIG. 1 container;

FIG. 4 shows a section through the separating wall of FIG. 3 as provided with automatically adjustable guide tongues;

FIG. 5 is a longitudinal section up to the axis of symmetry M/N, or transverse median plane, through a prior art coolant trolley of customary design;

FIG. 6 is a half segment of a trolley, modified, as in the invention, with FIG. 6 being a view showing a section plane AB oriented in a perpendicular plane and extending along the longitudinal axis;

FIG. 7 shows the plane AB from FIG. 6, with half a side wall exposed;

FIG. 8 shows, in a section format, the arrangement of the cooling insert with the guidance of the cold stream as incorporated in the trolley of FIG. 6;

FIG. 9 is an internal elevation view of the cooling gas channels in the side wall of the trolley of FIG. 6;

FIG. 9A is a transverse sectional view of the cooling gas channels depicted in FIG. 9;

FIG. 10 is a fragmentary top plane view of the cooling insert of the FIG. 6 trolley provided with transverse divisions or longitudinally spaced functional coolant zones;

FIG. I1 is a fragmentary, further enlarged view of FIG. 10, showing the cooling insert with details;

FIG. 11A is a sectional view taken along the plane CD in FIG. 11; FIG. 11B is a sectional view taken along the plane E-F in FIG. 11A; and

FIG. 12 shows a special embodiment of a layer for absorbing the condensate and additionally insulating the inside space against the cooling insert.

DETAILED DESCRIPTION In the embodiment shown in FIGS. 1 to 4, we are dealing with a so-called trolley, therefore a mobile container for prepared food, as used in airplanes. Here the requirements for cooling performance are particularly high, because within a limited time, and in consideration of the least possible weight of the device itself and its charge ofcoolants, a heterogeneous combination of foods as to quantity and type must be kept cool in an environment mostly of 24C., with the entire system being also subject to movements, for example, at starting of the plane.

FIG. 1 shows such a container in longitudinal section, in which the chilled goods 12 are kept on parallel flat shelves 11 and the dry ice 14 is disposed on the topmost shelf 13, the cooling insert. A door is located in this container at its left end, as viewed in FIG. 1. This cooling insert is connected on one narrow side or end of the container by means of a gap 15 with the work space of the shelves, in a manner yet to be described.

For thermal screening of the work or goods space against the cooling insert 13, an insulating plate (board) 16 has been provided, which does not impede the gap 15. Another insulating plate 17 curbs the heat transfer of the environment through the covering surface 18 of the container.

In order to guide the cooling stream, the entire container (including shelf 13) in this example has been inclined relative to the horizontal by about 2, so that the cold CO gas developing in the cooling insert 13 will reach the gap 15 on account of its specific gravity being 1.5 times greater than that of the air still in the work space. This inclination of the entire container is possible in case of the selected embodiment, since the contents to be cooled are not liquid in open bins (containers). Naturally the same effect could also be achieved by the fact that only the cooling insert has such an inclination, the chilled good inserts on the other hand being disposed horizontally.

A gate slit 25 is located at one end of shelf 13 and is followed by a descending shaft 21. Shaft 21 is defined by the narrow side (i.e., end) wall 19 of the device and a separating wall 20, parallel thereto. The cold stream in shaft 21 sinks to the bottom because of gravity. This cold descending stream can emerge from the shaft 21 through sluice-like apertures 22 which communicate with the work space between the shelves.

These sluice openings consist, according to FIG. 2, of perforations of the separating wall and of guide tongues 23. These tongues are shown in case of the FIG. 2 embodiment simply by a rectangle constituted by three cuts and a bent edge, each tongue being bent into the inside of the descending shaft 21 and facing up wardly in an inclined or baffle manner.

Naturally other geometric forms are also possible for the guide tongues, and their position in the descending shaft 21 can be flat or arched. It has furthermore been recognized that the descending shaft 21, at its lowest point, may be connected by apertures (which are not shown in the drawing) with the work space, so that condensate can emerge into the latter.

According to FIG. 1 and FIG. 3, these sluice apertures, except for the opening of the insert of the topmost chilled goods shelf which is connected with the descending shaft 21 by way of a slit 24, are provided for each of the chilled goods shelves, in such a manner that the effective width of passage means for emergency of the partial cooling stream into the shelves becomes larger with growing distance ofthe shelves from gap 15. The projection of the aperture in the direction of the cooling stream is to be understood here as the width of passage. This width of passage is here defined therefore by the effective size of the mouth of flow capacity of each such passage in chute 15 as governed by width and/or height of the guide tongue and the bending angle a in FIG. 2. Preferably the arrangement of FIG. 3 is to be selected, in which the sluice apertures 23 are disposed, displaced in the direction of the cooling stream and, as can be recognized, the opening angle a grows with the distance from the gap 25 and with it the above-mentioned width of passage. The increase in the size of the opening angle, in addition to increasing passage mouth size, tends to minimize the extent to which upper baffles 23 might shield" lower baffles 23 and impede flow into their associated passages.

It is furthermore essential that the baffle plate which constitutes the slit 25, and which runs across the entire width, screen the slit 24, which represents the connection of the uppermost shelf for chilled goods with the descending shaft 12. The reason for this is to avoid a too severe drop of temperature in the topmost cooling shelf. For the same purpose, bores or vents 26 are provided in the topmost cooling shelf, which lead into the open.

Each of the aperture means 24 and vent means 26 may be provided with selectively manipulatable closure means operable to selectively open (partially or fully) or close these openings.

The cooling container as in the invention can be filled in the customary cooling space at, for example, 6C. with food dishes of this temperature, and then be charged with dry ice and put to use. By the inclination of the container or the shelf 13, a path leading by gravity into the descending shaft 21 and through the sluice apertures 22 into the work space is forced upon the heavy CO gas. After a relatively short time an even temperature field pattern develops in the container, as a result of the distribution of the Sublimated dry ice according to the invention. The required pressure balance or differential takes place via the leaks in the doors of the container and through the abovementioned small bores 26 in the opposed long container walls between cooling insert and uppermost chilled goods shelf. By the arrangement of the bores 26 precisely at this spot, the most endangered topmost chilled goods shelf will be protected against freezing of the chilled goods.

It is apparent from FIG. 4 that, by the further development of the invention, an automatic control for the closing of the cooling stream by influencing the width of passage of the sluice openings 22 and thus of the partial cooling stream to the chilled goods shelves can be provided. In this connection, a rod 27 is provided which is connected on the one hand with the housing of the container and on the other hand with one movable guide tongue or baffle 30 and which moreover has a large temperature expansion coefficient. This rod 27 deflects the tongue 30, which is connected via a swivel joint or pivot connection 28 with the separating wall 20. The deflection is accomplished in such a way that in case of too much cooling the rod 27 contracts and the effective cross section or mouth size of passage of the sluice apertures is decreased. In case of too little cooling, the rod expands and this mouth size is enlarged. With the aid of the coupling rod means 29 it is possible to operate the sluice openings of several adjacent levels in the manner of levers by a single adjusting rod 27.

Naturally, the embodiment shown can have numerous modifications.

Thus, the invention can also be realized in case of containers with two doors at the two narrow sides (ends), by making the latter with double walls and by developing the inside walls of the doors as separating walls with baffle plate 25 and sluice apertures 22. In case of this embodiment, the function of the cooling stream depends even less on the inclination of the container. At a precisely horizontal position, the same quantity of cooling gas flows through the two descending shafts running on each end, inside the doors, and emerges through the sluice openings from both sides in the work space. The inflow of the cooling gas into the descending shafts can be facilitated still more by the coolant insert being buckled or bent in such a way that it slopes on both ends toward the inlet slits 25.

Furthermore, the invention is not only limited to the described movable small containers, but it can also be used in case of stationary large containers, perhaps the well-known container in the so-called igloo construction. It is always essential in this case, however, that the developing cooling gas is guided as a homogeneous cooling stream with a definite direction of flow and that it is then doseably distributed to the individual chilled goods compartments.

For the explanations of the modifications of the invention according to FIGS. 6 to 12, first of all, a trolley of customary construction will be described on the basis of FIG. 5. In the FIG. arrangement, the inside trolley space is divided in parallel planes 110 for the reception of the chilled goods 111. Above the topmost work plane is the cooling insert 112 with the dry ice 113. The stream of cooling gas drops, in this case, through a slot 114 along the door, without guidance, downward whereby either the left (or right) side is acted on more or less by the cooling gas as a result of the inclination and thus an undesirable, variable cooling is brought about at the sides of the door.

According to the invention the container now is developed according to FIG. 6 in such a way that the stream of cooling gas is fed under control inside the long side walls 115 to the spaces between the planes 110 which are to be cooled. The arrangement of the channels for controllably carrying the streams of cooling gas, according to FIG. 7 as shown by cut AB made longitudinally of the trolley, with the channels exposed to the right of exposure line VT, is made such that, with due consideration of the flow resistance, the channels leading to the lower planes, for example, 116 and 117, are developed broader than those which supply the upper planes, for example, 118, and that the broader channels are located on the sides of the door. (i.e., the channels on the right side ofline VT would be a mirror image of the channel arrangement on the left side.)

One example for the guidance of the cooling stream in the side wall is shown in FIGS. 8, 9 and 9A.

The shaped side wall 115 (in sandwich type construction) has on its inside the channels, for example, 116, 117, 118, already described. In the inside wall 119, deep-drawn supports 120 for the planes 110 (inserts) have been developed. A part of at least some of these supports has outlet slits 121 on their underside for the cooling gas, and they are adapted in size to the width ofthe channel, i.e., the wider the channel, the wider the slit associated therewith. In the upper planes there are small discharge slits, since there the cold radiation of the walls suffices for the cooling. There also is an insulating layer 122 applied to the wall in order to dam up or limit the cold radiation through the wall itself.

For reinforcement of the walls 119 at about half the height, a plane surface connected detachably with the wall elements 119, and not shown, may be provided.

In order to make possible a thorough cleaning of the trolley, the inside wall 119 can be removed.

The molded part 123, closing the trolley on top, houses the cooling insert or drawer 124 in which is located the dry ice 113. In the FIGS. 10 11,11A, and 11B and via the cuts or sections CD and EF, this cooling insert 124 is shown in detail.

FIG. 10 shows half the insert with its axes of symmetry P/Q (longitudinal) and R/S (transverse). The loading surface for the dry ice heap has been transversely divided by continuous transverse strips 125 and discontinuous longitudinal strips 126 into partial surfaces in such a way that, depending on the intended duration of cooling, the entire space of the cooling insert or partial spaces are filled with dry ice. The dry ice itself rests on a perforated bottom 127 on which there are formed continuous strips 129. As shown in FIG. 11, supporting rails 128 may support tray means 127. Up to certain inclinations of the device, the strips on ribs 129 will prevent the heap of dry ice from slipping during the starting phase of an airplane. The above-mentioned strips 129 thus serve as holding and isolating strips and may be at least partly adjustable and/or variable in height.

The connection of the cooling insert with the channels in the lateral walls is accomplished by openings 130. Between each two adjacent apertures there is each time a rail 128, which rail tends to cause equal quantities of cooling gas to flow downwards through all the openings 130 even at an inclination of the trolley, as shown by lines X/X. The t straight line Y/Y can be drawn just the same, which refers to a dry ice retention slope as provided by strips 125. The oblong holes 130 can be of different lengths, in accordance with the width of their associated channels in the side walls.

As this juncture, it will be recognized that the FIG. 6-11B embodiment is a species of the FIG. 14 invention, with the

spacebetween

124 and 127 providing a descending chute, branching off of which are central apertures 11 6, 117, 118.

The insulation 31 (FIG. 8) located on the underside of the cooling insert is of particular significance in order to prevent any undercooling of the topmost shelf or of the highest shelves by too great a degree of cold radiation through the base of the dry ice container.

In the first cooling phase, the heavy cold CO gas presses the air in the container upwards, and through leaks of the container into the open air. Water vapor condenses from this air and is deposited mainly on the insulating layer as a top limitation of the space, and iinally drips onto the chilled goods of the topmost shelf and generally defaces their appearance and value. The invention provides for an additional insulating plate 132 to be attached below the insulating layer 131 firmly connected with the molded piece 123, the raw material of said plate 132 being permeable and permitting water vapor to pass through, but absorbing droplets of fog and holds them, whereby the originally great heat resistance of the raw material is reduced by the water absorption. At the outset, the lowest layer of the insulation 132 with a 0C.-isotherm will constitute a cold brake or thermal barrier. The increase of the heat conductivity of this layer with the water absorption, which occurs during the cooling process in its first phase (the sublimation temperature of the dry ice does lie considerably lower in atmospheric air than a pure CO 2 atmosphere), serves to permit conductive cooling of the upper goods compartment while avoiding thermal shock due to a too abrupt cooling action at the outset. In other words, thermal shock due to excessive conductive cooling through layer 132, at the outset, is avoided, but such conductive cooling is gradually implemented as the thermal conductivity of layer 132 increases.

This insulating layer 132 can be produced for example by a fabric of plastic, for example, PVC, which after use in a container is removed and dried and is removed after repeated use for hygienic reasons.

A further embodiment of barrier 132 is shown in FIG. 12, where a bag 134 of special cellulose which absorbs or binds water is stretched across a resilient, U-shaped clip 133. A holding device 135 secures this assembly. The 134 bag is detached from clip 135 and thrown away after use and, since it consists of cellulose, is simply burned.

According to this example the dry ice is housed in a sliding drawer 124 which, for the purpose of being charged, is pulled out of the molded piece 123. In order to simplify the charging process, and in order to use dosing aggregates for the quantities of dry ice required for the cooling task, and in order to be able to accomplish the charging in series or on the conveyor, the top covering 135 may be developed as a tightly closing lid (not permitting any admission of air), which is swivelably articulated by a hinge 136.

If there is any desire to produce lower temperatures in the space of the top level, for example, for the storage of'ice cream, etc., then a direct gas connection to the cooling insert and to this space must be established by one or more closeable and in one dimension cntrollable apertures, possibly communicating with channel means such as 118, but which are not shown.

SCOPE OF INVENTION In describing the invention, its principal advantages have been delineated and made apparent, and a variety of structural and functional modifications have been noted.

Those skilled in the refrigerating art and familiar with this disclosure may recognize other additions, deletions, substitutes, or other modifications which would be deemed to fall within the scope of the invention as set forth in the appended claims.

What is claimed is:

1. In a transportable cooling container adapted to keep temperature-sensitive products, such as food and pharmaceuticals, cool during transportation thereof and having a work space subdivided into several vertically spaced product compartments for the cooled products including an uppermost product compartment a coolant compartment disposed above said product compartments, there being a tendency during transportation of said container for the compartments to become progressively warmer relative to a downward direction of reference; the improvement comprising:

at least one passage means descending from the coolant compartment and adapted to receive a gravity flow of gasified coolant; and

a plurality of vertically spaced apertures branching from the descending passage means and individually communicating with individual ones of said product compartments;

the sizes of the inlet mouths of said apertures increase progressively relative to a downward direction of reference such that said apertures divide said gravity flow of gasified coolant into increasingly larger portions relative to a downward direction of reference, to maintain the temperatures of said product compartments substantially uniform. 2. A cooling container as described in claim 1 wherein:

an upright baffle plate is located at an upper portion of said descending passage means and is operable to provide a constricted entrance into the uppermost product compartment.

3. A cooling container as described in claim 1 wherein:

said descending passage means, at its lower end, and

at a location shielded from said apertures, is operable to collect and drain condensate.

4. A cooling container as described in claim 1 wherein:

said coolant comprises particuted, solidified carbon dioxide.

5. Apparatus according to claim 1 wherein said transportable cooling container has support wheels, side walls, and front and rear ends spaced in the direction of container travel; said passage means extending laterally across and vertically along said rear end; at least part of said coolant compartment being inclined relative to horizontal toward said descending passage means to facilitate gravitational flow of coolant gas thereto; the apertures disposed beneath the uppermost product compartment including guide tongues extending outwardly and upwardly from their respective com- 35 partments and into said descending passage means; the horizontal locations of said tongue-including apertures being generally staggered relative to a vertical direction of reference to minimize the extent to which the flow of cooling gas into said apertures is impeded.

6. A cooling container as described in claim 1 wherein:

said descending passage means extends essentially over the entire height of the container and reaches across one side of the container;

said descending passage means is bounded on one side by an outside wall means of the container and on another side by a separating wall means extending essentially parallel to the outside wall means;

and

said separating wall means has sluice-like apertures,

each leading to an individual product compartment. 7. A cooling container as described in claim 6, wherein:

said sluice-like apertures comprise openings in the separating wall means and guide tongues extending from individual apertures and projecting from the separating wall means into the descending passage means at progressively greater angles of inclination along a downward direction of reference. 8. A cooling container as described in claim 7, wherein:

said container includes a door, located on a narrow side of said container; said door being operable relative to said compartments; said descending passage means is disposed on a side of said container opposite said door; and said descending passage means is disposed in communicating relation with vent means communicating with the exterior of said container.

9. A cooling container as described in claim 8, wherein:

said coolant compartment supports a coolant inclined in relation to the horizontal in such a way that it slopes downward toward said descending passage means.

10. A cooling container as described in claim 9, wherein the entire container, including said coolant and product compartments, has a downward slope, inclined downwardly toward said descending passage means.

11. A cooling container as described in claim 1 wherein:

said descending passage means comprise shaft means provided on opposite ends of the container; and at least an upper one of said product compartments includes vent means communicating with the exterior of said container and located on sides of said container extending between said narrow sides.

12. A cooling container as in claim 11, wherein:

said coolant compartment supports coolant inclined downwardly toward respective ones of saidshaft means to facilitate gravitational flow of said cooling gas toward said respective shaft means.

13. A cooling container as described in claim 12, wherein:

each of said shaft means is defined, at least in part,

by spaced wall means of door means of said container.

14. A cooling container as described in claim 1 wherein:

an aperture communicating with the uppermost product compartment may be selectively closed; and

said uppermost product compartment is operable to be selectively vented to the exterior of said container.

15. A cooling container as described in claim 14,

wherein:

said container includes an insulating plate disposed between said uppermost product compartment and said coolant compartment.

16. A cooling container described in claim 1 including:

movable closure means for said apertures located beneath the uppermost product compartment; coolant flow control means operable to operate said closure means to control flow of gasified coolant through said apertures in response to the temperatures of the respective product compartment communicating with said aperture.

17. A cooling container as described in claim 16,

wherein:

a plurality of said closure means are interconnected such that said coolant flow control means is operable to simultaneously control the flow of gasified coolant through said plurality of said apertures.

Claims

1. In a transportable cooling container adapted to keep temperature-sensitive products, such as food and pharmaceuticals, cool during transportation thereof and having a work space subdivided into several vertically spaced product compartments for the cooled products including an uppermost product compartment a coolant compartment disposed above said product compartments, there being a tendency during transportation of said container for the compartments to become progressively warmer relative to a downward direction of reference; the improvement comprising: at least one passage means descending from the coolant compartment and adapted to receive a gravity flow of gasified coolant; and a plurality of vertically spaced apertures branching from the descending passage means and individually communicatIng with individual ones of said product compartments; the sizes of the inlet mouths of said apertures increase progressively relative to a downward direction of reference such that said apertures divide said gravity flow of gasified coolant into increasingly larger portions relative to a downward direction of reference, to maintain the temperatures of said product compartments substantially uniform.

2. A cooling container as described in claim 1 wherein: an upright baffle plate is located at an upper portion of said descending passage means and is operable to provide a constricted entrance into the uppermost product compartment.

3. A cooling container as described in claim 1 wherein: said descending passage means, at its lower end, and at a location shielded from said apertures, is operable to collect and drain condensate.

4. A cooling container as described in claim 1 wherein: said coolant comprises particuted, solidified carbon dioxide.

5. Apparatus according to claim 1 wherein said transportable cooling container has support wheels, side walls, and front and rear ends spaced in the direction of container travel; said passage means extending laterally across and vertically along said rear end; at least part of said coolant compartment being inclined relative to horizontal toward said descending passage means to facilitate gravitational flow of coolant gas thereto; the apertures disposed beneath the uppermost product compartment including guide tongues extending outwardly and upwardly from their respective compartments and into said descending passage means; the horizontal locations of said tongue-including apertures being generally staggered relative to a vertical direction of reference to minimize the extent to which the flow of cooling gas into said apertures is impeded.

6. A cooling container as described in claim 1 wherein: said descending passage means extends essentially over the entire height of the container and reaches across one side of the container; said descending passage means is bounded on one side by an outside wall means of the container and on another side by a separating wall means extending essentially parallel to the outside wall means; and said separating wall means has sluice-like apertures, each leading to an individual product compartment.

7. A cooling container as described in claim 6, wherein: said sluice-like apertures comprise openings in the separating wall means and guide tongues extending from individual apertures and projecting from the separating wall means into the descending passage means at progressively greater angles of inclination along a downward direction of reference.

8. A cooling container as described in claim 7, wherein: said container includes a door, located on a narrow side of said container; said door being operable relative to said compartments; said descending passage means is disposed on a side of said container opposite said door; and said descending passage means is disposed in communicating relation with vent means communicating with the exterior of said container.

9. A cooling container as described in claim 8, wherein: said coolant compartment supports a coolant inclined in relation to the horizontal in such a way that it slopes downward toward said descending passage means.

11. A cooling container as described in claim 1 wherein: said descending passage means comprise shaft means provided on opposite ends of the container; and at least an upper one of said product compartments includes vent means communicating with the exterior of said container and located on sides of said container extending between said narrow sides.

12. A cooling container as in claim 11, wherein: said coolant compartment supports Coolant inclined downwardly toward respective ones of said shaft means to facilitate gravitational flow of said cooling gas toward said respective shaft means.

13. A cooling container as described in claim 12, wherein: each of said shaft means is defined, at least in part, by spaced wall means of door means of said container.

14. A cooling container as described in claim 1 wherein: an aperture communicating with the uppermost product compartment may be selectively closed; and said uppermost product compartment is operable to be selectively vented to the exterior of said container.

15. A cooling container as described in claim 14, wherein: said container includes an insulating plate disposed between said uppermost product compartment and said coolant compartment.

16. A cooling container as described in claim 1 including: movable closure means for said apertures located beneath the uppermost product compartment; coolant flow control means operable to operate said closure means to control flow of gasified coolant through said apertures in response to the temperatures of the respective product compartment communicating with said aperture.

17. A cooling container as described in claim 16, wherein: a plurality of said closure means are interconnected such that said coolant flow control means is operable to simultaneously control the flow of gasified coolant through said plurality of said apertures.