Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS2508385 A
Publication typeGrant
Publication dateMay 23, 1950
Filing dateAug 8, 1947
Priority dateAug 8, 1947
Publication numberUS 2508385 A, US 2508385A, US-A-2508385, US2508385 A, US2508385A
InventorsCharles B Hall
Original AssigneeCharles B Hall
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Refrigerator container cooled by carbon dioxide ice
US 2508385 A
Images(6)
Previous page
Next page
Description  (OCR text may contain errors)

C. B. HALL May 23, 1950 REFRIGERATOR CONTAINER COOLED BY CARBON DIOXIDE ICE Filed Aug. 8, 1947 6 Sheets-Sheet 1 FIG.|

lNVENTOR 3 'CHARLES B.HALL

wfi" A%NEY c. B. HALL I May 23, 1950 REFRIGERATOR CONTAINER COOLED BY CARBON DIOXIDE ICE 6 Sheets-Sheet 2 Filed Aug. 8', 1947- FIG. 6

INVENTOR CHARLES E. .HALL RNEY y 23, 1950 c. B. HALL 2,508,385

REFRIGERATOR CONTAINER COOLED BY CARBON nxox'm: I-CE Fill ed Aug. 8, 1947 e Sheet-Sheet s INVENTOR CHARLES B. HALL I May 23, 1950 c. B. HALL REFRIGERATOR CONTAINER COOLED BY CARBON DIOXIDE ICE Filed Aug. 8, 1947 G Sheets-Sheet 4 INVENTOR CHARLES B. HALL BYJZQ/ fig ATTORNEY y 1950 c. B. HALL 2,508,385

} REFRIGERATOR CONTAINER COOLED BY CARBON DIOXIDE ICE Filed Aug. 8, 1947 6 Sheets-Sheet 5 INVENTOR CHARLES B. HALL 'c. B. HALL May 23, 1950 REFRIGERATOR CONTAINER COOLED BY CARBON DIOXIDE ICE s Sheets-Sheet 6 Filed Aug; ,8, 1947 IA GRADlENT- OUTER INSULATION INNER CASING SHELL FIG. l4

GRADIENT-STEPI IFARAIDIENT-STEPZ 75 POUNDS (a) H INNER INSULATION SHELL APPROX. 3/4 OF CO1 F IG.

OUTER CASING V2 THE INSULATION REFRIGERANT 1/ OF co, CONTAINER QL GRADli-lIgT- STEP 2 GRADIENT-STEP 3 GRADIENT-STEP l CONDUCTOR PLATE DUCT Va CASING INSULATION v g r g c'roa v, INNER SHELL INSULATION GROOVE) g s gl OUTER CHAMBER CHAMBER FIG.-|6

INVENTOR CHARLES B.HAI L %!7 5?? ORNEY Patented May 23, 1950 REFRIGERATOR CONTAINER COOLED BY CARBON DIOXIDE ICE Charles B. Hall, Chicago, 111.

Application August 8, 1947, Serial No. 767,397

11 Claims.

This invention relates generally to refrigerator containers, and more particularly to storage and shipping containers for use in the transportation of quick frozen foods, and all other products, requiring constant freezing, zero or sub-zero temperatures but usually from F. to minus 20 F. The invention further relates to improvements in methods and apparatus for use with solid refri erants, such as carbon dioxide (solid CO2 or Dry Ice), and the like.

A principal object of this invention is to provide a method of refrigerating by means of solid refrigerants that shall be more efiicient than prior methods and shall materially extend the period of time for which a given quantity of the refrigerant will maintain the desired low temperature in the lading space of the refrigerator container.

The invention described and claimed herein resides in a novel way of applying all of the refrigerating properties of solid carbon dioxide (Dry Ice) and of the carbon dioxide gas sublimated from the solid carbon dioxide, by interposing the refrigerants in such manner as to intercept heat passing into the interior of the container from the outside atmosphere, causing such heat to be returned to the outside atmosphere instead of continuing into the interior of the refrigerator container, and the apparatus designed to interpose the refrigerants and to accomplish the heat transfer to the carbon dioxide gas being vented to an outside gas system or the outside atmosphere.

The invention described and claimed herein further resides in the disclosure of an application of the gradient step-down principle of refrigeration, wherein the normal gradient of a refrigerator container is sub-divided into two or more gradient steps.

Another principal object of this invention is the reduction of the gradient inducing heat transfer to the prime refrigerant of a refrigerator container through the application of the gradient step-down principle. It is an established fact in refrigeration that the greater the gradient, the differential in temperature between the outer surface of the container and that of the interior of the container, the more rapid the rate of heat transfer to the refrigerant. It is a purpose of this invention to divide the gradient of the container into steps, by interposing secondary chambers being chilled by gas Sublimated from the solid carbon dioxide,to cause the formation of two or more gradient steps, only one of which will induce the transfer of heat to the prime refrigerant.

Another object of this invention is the establishment of a closed gas system, including suitable chambers, interposed to intercept heat, the same gas being reapplied to the same path of heat in successive steps, in such manner that the gradient of the refrigerator container will be sub-divided into a series of steps.

Another object of this invention is to furnish a means for bringing the gas sublimated from solid carbon dioxide under control, housed in suitable refrigerating chambers, to act as a secondary refrigerant.

Another object of this invention is to provide a refrigerator container for the transportation of quick frozen foods and other products requiring a constant freezing, zero or sub-zero temper-' ature, and using a solid refrigerant, which retains the carbon dioxide gas in a closed circuit to preclude the contact of said gas with the food products in the lading chamber, a condition which causes a drying-out and desiccation of the products.

A further object of this invention is to furnish a means for the control of the temperature of a refrigerator container by the use of a pressure control valve in a closed gas system, designed to release Sublimated gas from the prime refriger-' ant chambers intermittently to the secondary refrigerating chambers, the variable frequency of this intermittent release being an effective temperature control.

A further object of this invention is to provide a sealed refrigerator container for the transportation of quick frozen foods and other products requiring constant freezing, zero or sub-zero temperatures, that will assure the maintenance of absolute sanitary conditions throughout an intransit period.

A further object of this inventionis to provide a refrigerator container for quick frozen foods and other products requiring constant freezing, zero or sub-zero temperatures, which will give adequate air circulation around the refrigerated products to insure absolute minimum growth of molds, inherent in cold storage operations.

A further object of this invention is to provide a refrigerator container, a multiple number of which may be used for the transportation of carload-lots of quick frozen foods and other products requiring constant freezing, zero or sub-zero temperatures, and one or more of which may be used for less-than-carload-lot shipments.

Another object of this invention is to provide a means for the even distribution of the refrigerant of a carload-lot shipment of quick frozen foods shipment remaining after partial unloading, and without appreciable loss of refrigerant due to ar:

tial unloading.

A still further object of this invention is to, proa vide an outside gas system to surround top perimeter of a multiple number"o'frefrigerator containers placed in a standard freight caiyto be,

suspended from the containers, between the cont ainers and the sides and ends of the freight car, to. be charged-withearboh dioxide gas vented from the gas system of refrigerator containers operated on thewgradient step-down principle, fer the purpose of. providing supplemental refrigerationand insulationfor the refrigerator containers placed in the freight car.

And still another obj'ecto thisiinvention is to provide a means for installing a supplemental protective layer of blown insulation arcund, above and beneath: a multiple number of refrigerator containers placed in a standard freight car; the

minute openings between the particles of iinsiula tion to' befilledwith carbon digxide' gas, released from an'outs'fide gas system'suspended around the top perimeter of the refrigerator containers.

Prior inventions have jmade a partial use of gaseous carbon 'dioxidato supplement the refrigerant action of the "solid -carbc jn dioxide, by

releasing the sublimated gas intoJthe lading' chamber, by releasing the gas into a secondary refrigerant such as a brine, by passing the gas around an area provided-between the insulating walls and the lading chamber, by releasing the gas into the insulate a ea, and in many other devices, but in no prior method is found the full utilization of the, gas as provided in this gra dientstep-dovvl'i principle. l

Still other and more specific objects and advantages of. this invention will become apparent from" the description hereinafter set forth of one embediment or example thereof, and from the accompanying drawingsto which the descriptidn has ref l fi f V In the drawings;

Fig, 1 is an exterior fr nt andside angle view with'the door closed, of one embodiment of a refrigerator container;

Fig. 2 is a front View of the same container, with the door open;

Fig. 3 represents 9, vertical sectional view from the front taken on line3-3 of Fig. 4;

Fig. 4 representsa vertical sectional View from the side taken on line 4.,4'of Fig. 3;

Fig. 5 represents 'a fragmentary perspective,

view of the Solid carbon dioxide" chambers and the piping system for the release or the sub-v limated' gasto the secondaryrefrigerant chambers;

Fig. 6 represents an enlarged, fragmentary cross section of a side wall, showingthe assembly of the secondary refrigerating'chambers;

Fig. 7represents'a'perspective'view of the component parts of the first secondary refrigerating chamber, or groovedchjambemf "periods, and during temporary delay .in loading for long-distant, carload-lot shipments. Be-

Fig. 8 represents a perspective view of the com ponent parts of the second secondary refrigerating chamber, or duct chamber;

Fig. 9 represents a perspective, fragmentary view of the over-all gas system;

Fig. 10 represents a vertical cross sectional view of a freight car loaded with refrigerator containers, taken from the side of the car;

Figllrepresents a vertical crosssectional view of afreight car'loaded with refrigerator containers, taken from the end of the car;

i Fig. 12 represents a fragmentary, perspective view of an outside gas system, charged with carbo'n dioxide gas through a flexible connection joined" to'the vent of the refrigerator container;

'Fig." 13' represents a fragmentary, transverse view of a loaded freight car, with the outside gas system"and supplemental blown insulation in plaeef, taken from the end of the car on a setback basis;

Fig. 14 is a diagrammatic illustration of the path and transfer of heat tothe refrigerant in an ordinary refrigerator container;

Fig. 15 is a diagrammatic illustration of the path and transfer of heat, as it would'occur, if

it were practical to install a part of the refrigerant between divisions "of the insulation in the walls of a refrigerator container'j'and.

Fig. 16 is a diagrammatic illu'stration of the path and'transfer of heat to the secondary refrigerants and to the primerefrigirant', mare fri'gerator container embodying'the apparatus for the functioning'of the gradient 'stepedcw'n principle V The quick frozen food industry .hasbecome one of the fastest growing industriesina' little more than one decade, and givesprornise of continuingfeven accelerating, this rapidp'ace of growth. One of the major problems of the industry is the maintenance orconstant, relatively low temperaturefrom the moment of quick freezing until the'time of intentional ,dewfrost'ing for eating purposes. This problem isrea'son'ably simple in the processors plant; in the wholesalers "storage and in the retailers display To date, the maintenance of these constant low temperatures during iiietransit perio'd'shas 'beenexceedingly difficult, and "much of the inferior duality product which has appeared on the: market hashad this inferior quality impartedfto it. 'duringperiods. of transportation.

Thisinvention will furnish the necessary refrigerated protectiontoall quick frozen foods and other products. v requiring constant freezing, zero and sub-zero temperatures, during ill-transit and unloading at shipperand consi nee terminal points' Shipments of quick frozen foodsandthe likev may be readily classifiedinto carloaddot ship merits, and less-thanwarload-lot "shipments.

Carload-lots are usually shipped y freight; less than-carload-lots are usually lshipped by. express, truck or 'air. Theperiod of 'in-transititime'for less-than-carload-lots is usually brieferthan that cause, of these two general classifications, the description which follows hereinafter is'idivided into two sections, first, the operations which are common to all s n s, andseeongl, the, additional p t ction pr vided for can d lete.

By making use of therefrigeratorcontainer of this jinventiom'all shipmentsof quick frozen foods, and other products, re u ring constant freezin Zero or subs-Zero, tern eriattires may; be

made in ordinary freight cars, express cars, ordinary'trucks and freight planes; refrigerated cars and; refrigerated trucks will not be required.

Therefrigerator containers designed and used TOI'jCfiI'lOEid-IOt shipments must of necessity be of a size which will permit the use of the maximum space of the freight car, and with this consideration in'mind, it has been found that a container of a'size'which will permit the placement of eight such containers from end to end in the car, and twofrom side to side, utilizes the space in the average freight car to excellent advantage, although it' is obvious that a container for this purpose need not be confinedto these dimensions. Containers of this size may be readily handled by either manual or automatic lift trucks, and since such shipments will usually originate and terminate at cold storage terminals equipped forhandling suchshipments, no difficulty will be encountered.-

The refrigerator containers designed and used for less-than-carload-lot shipments, will usually be of a size more conveniently handled in LCL traflic, thoughthe larger container may be used where practical. The principles of construction and of operation are identical, except for the added exterior insulation and refrigeration provisions made in the freight car for thehandling of long-distant carload-lot shipments.

The refrigerator containers are extremely durable in construction to withstand the severe handling involved in transportation and yet the over-all weight of the container is low due to the relatively lightweight material used in construction.- It is important that excessive tare not be added to the weight of the shipment.

In the form chosen for disclosure herein, the invention is embodied in a refrigerator container C having an outer casing I of light weight but durable metal or like material, reinforced with bracing members as is the practice in such construction. The container C has an inner shell 22 that is of lighter weight metal or other material and is also braced with supporting members 23, anda door 3 afforded that is constructed to close flush with the outer casing, being secured by locked nuts fitted over threaded studs 5 protruding from the Walls and inserted through recessed openings in the door. The outer casing or shell I', and the inner shell 22 are supported in conventional heat-breaker relation, and the same is true with respect to the inner and outer walls of the door 3. Provision is made in the form of a rubber gasket 6 for sealing the door tightly, toninsure air-tight protection to the lading compartment during transit periods, and recessed gripping wells 1 are provided for handling door... Each container is mounted on skid legs-4 formed by the extension of the corner bracing members, to permit handling with me-- .chanical equipment. An outer gas vent 8 is recessed in the side or top of the outer casing for protection, andis threaded to permit the attachment of flexible pipe connections 55 in the freight car as will hereinafter be described in detail. An emergency pressure release vent 9 also afforded and is also recessed in the side or top of the outer casing.

Since no object on the exterior of the containers C protrudes beyond the surface of the outer casing, when loaded into freight cars, it is possible to, place them flush against one another, forming a compact unit set away from :the ends 49 and sides 50 of the car, with a six or eight inchspace on .all sides of the container,

6 and with the doors of the containers turned inwardly against another container. This arrangement materially reduces the area of the container surfaces in the freight car exposed to heat transfer.

In the carload-lot containers, one or more solid carbon dioxide chambers (prime refrigerant chambers) H are provided, however, in the smaller less-than-carload-lot containers, only one prime refrigerant chamber is necessary. The prime refrigerant chambers II are suspended in brackets 12 from the top of the inner shell 22 and because of the relatively heavy weight of these loaded chambers, and due to the shunting and jarringof the freight cars in transit, and therefore of the refrigerator containers, substantial bracing members l3 are placed from the chambers to the inner shell and between the two chambers.

The doors [4 of the prime refrigerant chambers are arranged with rubber gaskets I6 and mechanical sealing devices I5, to insure gastight sealing of the doors of the prime refrigerant chambers. Suitable piping I1 is provided to exhaust the Sublimated gas from the prime refrigerant chambers and an emergency pressure release valve 19 is installed in the piping circuit to cause the venting through the vent 9 to the outside atmosphere of any undesired pressure of gas which might accumulate.

Under and in accordance with the present invention the gaseous refrigerant that is sublimated from the solid carbon dioxide Within the chamber or chambers ll serves first, of course, to cool the walls of the chamber or chambers l I, thereby to cool the ambient air Within the lading chamber of the container, and such gas is thereafter passed successively to a plurality of secondary refrigerating chambers that are disposed in heat transfer relation to a similar plurality of walls located in spaced relation to each other in the space between the inner and outer shells of the container C. Thus in the form herein disclosed, each wall of the container C has a pair of plates or walls 34 and 34A disposed therein in spaced relation to each other and to the inner and outer shells of the container, and these walls are made from a material such as metal so as to be good conductors of heat. The wall 34 is closest to the inner shell 22 and has a refrigerating chamber 35 associated in heat transfer relation thereto; while the wall 34A is disposed between the wall 34 and the outer casing I and has a secondary refrigerating chamber 39 associated therewith in a heat transfer relation. The gaseous refrigerant is under the present invention passed from the chamber or chambers I [through the chamber 35, then through the chamber 39, and is then vented from the container C by the vent 8 as will hereinafter be described in greater detail.

It will be observed that a flexible pipe connection 20 has been made from the gas exhaust piping to the secondary refrigerating apparatus or chambers of the refrigerator container door for the input of carbon dioxide gas and another flexible connection 2| is provided for venting the gas from the secondary refrigerating apparatus of the door.

It has been found that this invention functions well for certain temperatures and certain purposes without the installation of a pressure control valve IS in the closed gas system, however, the installation of such a valve is preferred, for by regulation of such valve l8, the

me ts:

d; s in t e se e da e r ee e s .e ee bersand y he ch n ed; withc u b" i t ney a m v be requi d .te me e eiett eel sired. temperature within the refrigerator container lading compartment. U n a i e e ina m mbe ce e n at d r he 4 e ede ee taet o n s et eiene .elie bracing members "23,and to these S shaped sun Porting mem e a e t tt eh ti ene ei el 1 5??? rs 25 o receiving endhe slin thela iee trays '6 s el e of the e taie Fresh; 9 shelves; areof open construction to "permitfree circulation of air around'thela ding E rotrudin g contacts 21 "are attached to the; tops anol bottoms cf the sides of the trays, to;i nsure further air circulation and togive'firmstorage in the conai or e e h t dur ng t ns t:

1 e se pf nnove i e nd y r ri atin chambers 35 and 39, installed in the side walls of therefrigeratorcontainenand to insure a dryness of the insulation material in the side walls at all times, provisionis made for the periodic drying of the insulation by forcing a, slow stream of heated, dry airinto the insulated walls for which purpose a normallyclosed insulationdryer inlet; 28'and a normally closed insulationdryer outlet-29 areprovided in the inner shell-of the refrigerator'container. h

The side walls a-nd'door of the refrigerator container are constructed-with three layers ofinsulation Si, 32-, and -3-3,Fig. l6, between which-are interposed the two walls 34' and 34A Wit1lft1lQi1 secondary refrigerating chambers 35 and 39. This insulation may take the form of reflective insulatioma's indicated'in Fig.: 6,-or may1 takethe form of fibrous or like material in either bulk form-'or'inshe'ets, as indicated-in Fig. 16. It will be-notecl in'Figs. "6 and lfithat onelayer of insulation 3 iis'placed outside-of theinner} shell 2-2, after which the first of thesecondary refrigerating-chambers' 35 and'its heat transfer wall34 are installed against shoulders 46. This chamber 35 is herein more specifically termed 'the -grooved chamber, dueito the nature of its "construction, and is --mcre fully-described hereafter. This is followed by another layer of insulation 32 and then the installation-ofthe Second secondary refrigerating" chamber B-Wa'ndtits heat transfer wall 34A, the-chamber 39: being herein designated as the-duct chamber; and more :fully'described later. Another layer of insulation 33" is placed between this "second; secondary refrigerating "chamber 39 and the outer casing -i. The insulations-pref erred in 'this invention are those known "astFerro-Therm or Fiberglas, however, it has "been found that those commercial products known-as Dry zero, rock *wool; and several others-will'serve the purpose. -Ferro-Therm insulation -is" commercially available and comprises 'a: -ste'e1*sheet covered onone-face b'y an -alloy;coatingof "lead and tin with a finishing film of palm oil overthis coating. 'Fibergl'as insulation isalso-commerci'allyavailableand' is afiordedby abody of relatively fine glass-fibers that areusually depositedfin the'form' of a mat or b'attso that thisbattmay lee-"disposedin the'space between two walls. "Dry Zero insulation 'is available commercially: and is afforded in either bulk or -battform. The Dry Zero material is made from fibers of-the pod'of the tropical *Ceiba' t'ree. Rock "wool similarly available in either" bulk or 'batt for'm; F and this material is *in the form of *fib'ers "made T from a mineral or rochrrnaterial. l 4

The piping ll provided for' the' escape oI the carbon dioxide gas *from* the prime refrigeranteeembe U "th n w seeee xeeeeae chamber 35 and the ductsecondary refrigerating w es bte e lexl ue e sfa m the-Prime re u e!- e'e 'eheme re 1! releieseexeneee esee u o the dpen'ing of the pressure control valve 18, is res e. int t e a eeve veeee e c rvix. ris ret umber-e5 and theme chi herteme tur a .eete ee m mbe s? i fe eeq th ou h. the ee nee n, Mime the e eee erx r e ti s chambe te hwhieh ceas t e P 9 stil -h er tem eratur -Je r eha zb 3,9 o be forcecl out through theconnection '45 to be reeeiefeqth e ht e eneer v r c .7 c

While hetwe. eee nciery; efr era n c e t amed-i3; e o im e u 9 s i x ere ienv ztber fe e he r i e sn.;are s h siii l 'e t- The first. of th e d ry v e ret e' hem e si sneWn-es e i e d a e has a specific reason for its *design. A block of aluminum; or other good heat conductor material, approximately ;inch thick "and l0 -inehes wide! s .e t with: a neherooved patt rn .6; s she j in Figure fl, -'I -his block'is then welded er iea l st ei en erofsa; nt grpla ei o a surf aee; area of 'the'lengthand width of the inee imensi eeei the si ewa11, -withthe grooved surface placed ;-inwardly toward the conductor mounting plate 34,; to form-the equivalent {of a ;inch coi l mounted on "a conductor mounting plate. :In-;f act,-= a coil so mountedbut withfa good heat conductor 'joint' throughout 'may be used.

This small-path-for the passageof the gas downward, when ireleased under pressure from the prime-refrigerant ichambers; for the purposeof -forcingfall of'themld; highertemperature gas forward in the gasgsystem;withoutpermitting counter currents of thehigher temperature gas to;moveupward or backward in 'the system. 7 a The second "of the ."secondary. "refrigerating chambers "39* is constructedbvwelding *a duct of aluminum-qflor-othergood heat-"conductingmateriaL-approximately in'Ghdeepahd 10'inches j'vvide,1ivertically 'to a"con'cluctor mounting plate 34A "of the same-good*heatnondticting*metaL a plateo'f *t-he length andwidlmbfthe inside'di'm'ensions of 'the sideg walk; When gas'is forcdoutbf the first; secondary "refrigerating- 'chainber 35, at the exit :3 8"through the'poor heat conductor *connectio'n i'd; it ri'ses' from the entry l in" the "duct of the seccnd "secondary refrigeratingchamber 39',"the warmer gas' being-of lighter-weight: to be vented nomthe refrigerator? container through the exit 42 and the vent 3. Whfle certa'in dilnehsicns are usedin the' foregoing description "for purnoses of"explanation; is* obvious thse'seoondary 'i'frigeratirig "=chambers "may be *co'nstructed -inwariofis sizes and propbrtions 'as fl't thei'equireni'ents'; :"Anotlier' princifial' feature of this inventiofils the' novel" method for brawning -aealtibnarinsulation and refrigeration for a mass of refrigerator containers, in the storage of such containers in the freight car. This method is only possible because of the nature of the construction of the refrigerator container of this invention and its principles of operation, and for that reason is included in this application as another of the principal claims of thi invention.

The loaded refrigerator containers C are shored into the freight car through the use of planking 53 and mechanical Jacks 54, as shown in Figure 13. This is a progressive operation, performed as the containers are moved into the car. The following additional operations are also performed progressively as each container is placed in the freight car.

Perforated piping 56, suflicient to extend around the perimeter of the mass of refrigerator containers loaded into the freight car, is provided. This is jointed in practical lengths, approximately the length of one sidewall of the refrigerator container, of a type easily joined and secured by a friction fitting 51, or some other simple means of connection. Each length has a connection 58 for the attachment of a flexible pipe 55, the other end of each flexible pipe being connected to the vent 8 of one of the refrigerator containers.

A perforated and screened metal cover 59, round except for a flat surface on the side toward the container, with a screened opening in the bottom, is provided in similar lengths and is similarly capable of being easily joined 60, to surround the perforated piping and disposed by means of bracing members about two inches from the circumference of the perforated piping. Strap hangers 62 are arranged to suspend the perforated piping 56 and the metal cover 59 from the recessed wells I l! of the outer casing of the refrigerator containers. When all containers have been loaded into the freight car, an outside gas system of perforated piping with protective metal covering, with screened bottom opening, will surround the perimeter of the mass of refrigerator containers, near the top of said containers, and disposed between the outer casing of the mass of containers and the sides and ends of the freight car.

As containers are loaded into the freight car and the outside gas system is installed and connected, a layer of loose insulation is blown into the freight car in all open area between the mass of containers and the roof, floor, ends and sides of the freight car, the outside gassystem being comcover 59, and from the screened openings of the" metal cover into the blown insulation 6! surrounding the mass ofrefrigerator containers, to seep through the minute openings between the particles of blown insulation to form a blanket of insulation and refrigeration to further inter-' cept heat entering through the walls of the freight car, before such heat can come into contact with the surface of the refrigerator containers.

Inthe operation or use of the containers of this invention, though they are of simple mechanical construction, care should be exercised in their packing, charging and loading to secure the best results. It is desirable to pre-cool the container "in a cold room of approximately minus 20 F.

Such heat, if any, will by thelaws of nature, rise g temperature, to insurea constant freezing, zero or sub-zero temperature immediately upon the lading being placed in the container. When the refrigerator container has been brought to the desired temperature, the lading compartment should be thoroughly sterilized with an ultraviolet ray lamp.

The lading which has been maintained at low temperature is then packed in the container trays and the trays positioned in the lading compartment of the refrigerator container. The prime refrigerant chambers are then charged with solid carbon dioxide (Dry Ice) and these chambers are sealed, after pressure valves have been checked. Carbon dioxide gas is then forced through the gas system, under pressure, to remove all air or warm gas from the system and to reduce the temperature of the gas system to the desired point. The gas system is then connected to the prime refrigerant chamber gas outlet. The lading compartment door is closed and sealed, to insure that this compartment will remain air-tight during transit.

If the shipment is less-than-carload-lot, the container or containers are then ready for shipment. If the shipment is a carload-lot, the loading operation requires further description.

For carload-lots, further insulation and refrigeration is provided. Beginning at the ends of the car and loading toward the middle, loaded refrigerator containers are placed two across in the car. Mechanical jacks and planking are used to shore in the containers, car dimensions being taken into consideration, to divide equally the surplus space which will remain around the mass of loaded containers, at the ends and sides of the car.

Joints of perforated piping, to form the outside gas system, are suspended by the strap hangers from the recessed wells in the ends and sides of the containers, and are joined one to the other, as the containers are placed into position. Connections between the container vents and the outside gas system are'made, and the sawdust or other insulation is blown into the open areas surrounding the mass of containers. The gas escaping from the outside gas system will gradually seep through the insulation to fill all available openings, giving a drying and refrigerating effect.

The unloading operations begin with the removal of the blown insulation, by means of the reversed blower device. The outside gas system and the metal covers are removed as the con tainers are unloaded.

All refrigerator containers, whether carload-lot or less-than-carload-lot shipment are immediately placed in the cold'room at the receiving terminal upon arrival and the container is checked for temperature and forcondition of the lading,

The automatic operations of the refrigerator container en route is controlled by the transfer of heat to the prime refrigerant and the development and intermittent release of the evolved gas of sublimation to the secondary refrigerating chambers by action of the pressure control valve.

There are but two sources of heat in the interior of the refrigerator container, that which results from the oxidation of the products of the lading chamber, and that which enters the walls of the container by conduction or radiation. The heat of oxidation may be ignored, for the amount of heat so generated in a sealed container at freezing, zero or sub-zero temperature is negligible.

toLthe upper area :oflthecontainer. to .be :brought into contact .convectively; with .theconductorplate upon': which rests-- the: solid: carbon dioxide,- and will thus betransferred to therefrigerant.

A'ny heatenteringithe interioroflthe container, through the walls, will likewise rise-by convecltive currents. to be transferred. toxthe prime'refrigerant by. contact with theconductorv plate; Allaheat so transferred to the; prime :refrigerant will cause the sublimation of gas; to' be.-- forced underi'th'e pressure oftheaccumulatedgas into the gas system? and the secondary refrigerating chambers;

' The. gradient step-down'principle is best described iand explainediby'reference toFigures 14, 15' and 16,.wherein the. path: of heat entering through the walls ofi refrigerator. containers and the transfer of. said heat tosthecontainer refrigerant; or refrigerants, is'diagrammatically illustrated for" first, an: ordinary; refrigerator container (Figure 14) secondly; aztheoreticalrefrigerator'container (Figure 15) and thirdly, .a refrigerator: container: embodying: thegradient stepdown principle." (Figure 16)..

In Figure. l lgtheouter casing I01, the-insulation It I, the'inner'shell 122; theirefrigerant chamber H1, and: a fragmentary view of. anzordinary refrigerator container XI are illustrated; Heat entering through thewalls :of: thecontainer is indicated by H; H I-I jand' H? and the ascending sequence indicates the direction: of flow.

From this illustration": it will.- be' observed that allv heatwhich successfully*enters1the: interior of the container, by passing througlithewalls of the container, is ultimately brought into contact with the refrigerant chamber; in this: case there being only one refrigerant chamber; and; is transferred byc'o'nduction .tofthe refrigerantzcausinga refrigerant consumption in? direct proportion. to the amount" of .heat absorbed;

In' Figure 15,. then outer'c'asing 20],. the outer insulation. layer. 2.32,. a: theoretical placement. of a-partfofthe refrigerantzl lAb'etween-divisions of the insulation; the? inner insulation layer 23 l, the inner shell 22!; the." refrigerant chamber: 2 H and a. fragmentary view" of a; theoretical.. refrigerator container. Y. are: illustrated. Heat entering through the walls of the container is indicatedxby H I, I-I ',.H ;,H ,.and El -and the? ascending sequence indicates the direction: of" flow.

If'it were practical'to construct arefrigerator containerasidescribedz in this drawing; a part of the refrigerant would be interposedzbetweenidivisi'ons ofv the insulatiorr in: such. a. manner as to intercept heatlentering thecontaincr before such heat reached the interior of the container. Heat brought into contactwiththe-refrigerating chamber .2 IslA, containingthatpart of the refrigerant interposed in the walls of the container, would,

cause-a consumption of the refrigerant inchamber 211A, and would-not. inducea transfer ofheat to=the refrigerant in chamber. 2 H, thus conserving for a longer period. oftime. that. refrigerant in chamber 2-H. However, no practical gain. results from this arrangement as an actual. consumption of refrigerant occurs, partial consumption occurring in chamber- ZHA rather-than in chamber 2 t.

IniFigure. 16', component: parts of a refrigerator container embodying the "gradient step-down principle ofthis invention. are. illustrated. In the construction of this container} the outer shell I the outer insulation.- layer 3'3, the second secondary refrigerating chamber (ductchamber) 3.9,. and its heat transfer wall 34A, the center insulation; layer 32,, the first secondaryrefrigerating chamber. (grooved: chamber) 35-. and. its heat transfer. wall. 34, therinner. insulationlayer 31, the inner. shell .22, theprimerefrigerant. chamber H l andlthe. fragmentary view of therefrigerator container C are arranged asthe component parts and apparatus of saidirefrigerator container are placed in actual. construction. Heat entering through=the wallsofthe container is indicated by H, H H H H4, 11 H and H and the ascending sequence indicatesv the directionof. the flow= From the.previousdescriptiomof the construction .and operation of thislrefrigerator container, it will be recognized thattherprimerefrigerant (Dry Ice) is placed in the prime refrigerant chamber [Land thatthe evolved gas of sublimation accumulates in the. gas-tight chamber until the desired'pressure hasbeenbuilt up against the pressure control valve. l8 in the gas system, whereuponit is released to beforced into the first secondary refrigerating chamber 35; which inturn forces the old,.higher-temperature gas in chamber tiinto the second secondary refrigerating chamber 39, the old, higher-temperature gas ofthat chamber being forced from the gas system through the vent in the outer casing to the outsidegas system, or to the atmosphere. Since the secondary refrigerating chambers are isolated againstheat transfer from one to the other, and from all other sections of the gas system, by heat breaker connectionsmade of poor heat-conducting material, this refrigerator container has three refrigerating chambers, the two secondary refrigerating chambers so disposed astointercept heat from the sides before it reaches the interior of thecontainenand the prime-refrigerant chamber which absorbs heat reaching the interior of the container with the: resulting sublimation of further gasfor the. replacement of old gas which has been warmed somewhat in the secondary chambers.

Although the temperature of. the prime refrigerant, and the gasin thevarious steps of the gas system, will vary somewhat,,let us assume, for purposes. of illustration andexplanation, certain reasonable temperatures throughout the gas system. The temperature of the prime refrigerant may be assumed. to be minus 110 F., that of the newly Sublimated gas under pressure control in the prime refrigerant chamber as minus F. tominus60 F.,,that of the firstsecondary refrigcrating chamber as minus 60 F., to minus 10 F., that of the second secondary refrigerating. chamher as. minus. 10 F. to plus 30 F. and that of the gas being vented to the outside gas system, or to the atmosphere, as approximately plus 30 F.

Itwill be obvious to those skilled in the art that atransfer of alarge percentage of the heat entering the Walls of the container has been made to the cold gas of the second secondary refrigerating chamber, raising the. temperature of the gas of .this. chamber from minus 10 F. to plus 30 F.,

after which it is vented from the container. Likewise, a large amount of, the heat which was not intercepted by the second secondary refrigerating chamber, throughthe medium. of .the conductor mounting plate, has. been transferred to the cold gas. of the first secondary refrigerating chamber, raising. the. temperature of the gas of this chamber from minus 60 F. to minus 10 F., after which the gas is forcedinto the. second. secondary refrigerating chamber- That heat which. did. enter the. interior of the refrigerator container, and was brought into conrefrigerator container.

asoassu tact with the prime refrigerant chamber for transfer to the prime refrigerant has consumed an amount of prime refrigerant in direct proportion to the amount of heat transferred, and further heat entering the prime refrigerant chamber or chambers has raised the temperature of the newly Sublimated gas from minus 85 F. to minus 60 F.

If we assume all conditions of operation of the three containers described in Figures 14, 15 and 16 to be the same, except that of the difference in construction and the placement of the refrigerant, as illustrated in the three drawings, and we further assume the use of the same weight and volume of solid carbon dioxide as a refri erant, the combined volumes of refrigerant in chambers 2IIA and 2 of the container illustrated in Figure 15, would be consumed in approximately the same period of time as that in the container illustrated in Figure 14, while maintaining relatively the same temperature in the lading compartment. However, since a very large percentage of the heat entering the refrigerator container illustrated in Figure 16 is transferred to the evolved gas in the secondary refrigerating chambers, only that heat reaching the interior of the container will induce heat transfer to the prime refrigerant. Therefore, the same quantity of prime refrigerant in this container will maintain the desired temperature in the lading compartment for a much longer period of time.

It will be noted in Figure 14 that the gradient I A which induces the transfer of heat to the refrigerant is the temperature differential between the surface of the outer casing and that of the interior of the refrigerator container. I In Figure 15', the gradient of this theoretical container has been divided into two steps, step I B which is the temperature differential between the outer casing the gradient step IA induces the transfer of heat to the refrigerant in chamber 2i I.

In Figure 16, which is an embodiment of the refrigerator container of this invention and therefore an illustration of the gradient stepdown principle, three gradient steps are established. The'first of these, step IC is the temperature differential between the surfaces of the outer casing and the second secondary refrigerating chamber, the second, step IB, is the temperature differential between the surfaces of the second secondary refrigerating chamber and that of the first secondary refrigerating chamber, and the third, step IA, is the temperature differential between the surface of the first secondary refrigcrating chamber and that of the interior of the Only the innermost gradient step, IA, induces the transfer of heat to the prime refrigerant, and since this is only one -:part of the total gradient of the refrigeraton,

Whi1e I .have described my invention in some detail, and with specific reference to one embodiment thereof, it will beapparent, especially to those skilled in theart, that various modifica- -,tions may be made in the form of the container and in the apparatus for; applying theprinciples spaces between said walls and between said walls '14 of the invention, and that certain features may be used to advantage, without a corresponding use of the other features, all without departing 'from the spirit of my invention. I therefore desire, by the following claims, to include within the scope of my invention, all such similar refrigerator containers, refrigerator cars, trucks, and other refrigerating devices, for this and all other end-use purposes, whereby substantially the results of my invention are obtainable by substantially the same means.

Iclaim:

1. In a, refrigerator container for frozen foods or the like that require freezing, zero or sub- .zero temperatures, an inner shell defining a lading compartment, an outer shell surrounding said inner shell in spaced relation thereto, a plurality of intermediate walls made from metal of high heat conductivity and disposed between said shells in spaced relation to said shells and to each other, insulating material disposed in the spaces between said walls and between said walls and said shells, means defining at least two secondary refrigerant passages disposed respectively along and in heat transfer relation with respect to different ones of said intermediate walls, means disposed within said lading chamber and adjacent the top thereof to define a primary refrigerant chamber adapted to contain solid carbon dioxide, a refrigerant discharge passage from said primary chamber including a constant pressure control valve, means of low heat conducting material connecting said refrigerant discharge passage with one end of one of said secondary refrigerant passages and connecting the other end of said one passage to one end of the other secondary passage to transmit gaseous refrigerant successively through said secondary passages, and means affording a vent extending through said outer shell from the other end of said other secondary passage.

2. In a refrigerator container for frozen foods or the like that require freezing, zero or sub-zero temperatures, an inner shell defining a lading compartment, an outer shell surrounding said inner shell in spaced relation thereto, a plurality of intermediate walls made from metal of high heat conductivity and disposed between said shells in spaced relation to said shells and to each other, insulating material disposed in the and said shells, means defining at least two secondary refrigerant passages disposed respectively along and in heat transfer relation with respect to different ones of said intermediate walls, means disposed within said lading chamber and adjacent the top thereof to define a primary refrigerant chamber adapted to contain solid carbon dioxide and having a refrigerant discharge passage, means of low heat conducting material connecting said refrigerant discharge passage with one end of one of said secondary refrigerant passages and connecting the other end of said one passage to one end of the other secondary passage to transmit gaseous refrigerant successively through said secondary passages, and means affording a vent extending through said outer shell from the other end of said other secondary passage. i

3. In a refrigeratoncontainer for frozen foods or the like that require freezing, zero or sub-zero temperatures, an inner shell defining a lading compartment an outer shell surrounding said inner shell in spaced non-heat-transmitting relation thereto, a plurality of intermediate walls 'rma de from metal I of high heat conductivity and dlsposecl= betweensaid shells: in spaced relationto said shells andto eachother, heatbreaker means supporting said intermediate walls, insulating material disposed in the spaces between said walls and between said walls and saidshells, means defining; secondary refrigerant passages disposed respectively along'andin heat transfer relation withrespectetodifferent ones of said intermediate walls; means disposed within said lading chamber and adjacent: thetop thereof to define a primary refrigerant chamber adapted to-contain solid carbon dioxide-and'having a refrigera-nt discharge passage,- means of low heat conducting material connecting said: refrigerant, discharge passage with saidsecondary refrigerant passages inseries and terminatingin a vent extending through said outershell.

4; In a refrigerator containerforfrozen foods or the like that require freezing,- zero or sub-zero temperatures, an inner shell defining a lading compartment, an outer shell surrounding said inner-shell in spaced'relation thereto, means recessed into outer shell and afiording a vent, a

pluralit of intermediate walls madefrom metal of" high heatconductivity and disposed between said shells in spaced relation to saidshells and to each other, insulating material disposed in the spaces between said wallsand said shells, means defining secondary refrigerantpassages disposed respectively along: and in heat transfer relation with respect todifferent; ones of said intermediate walls, means disposed within said lading chamber andBadjacent the top thereof'to define a primary refrigerant chamber: adapted to contain solidcarbon dioxide andthaving a refrigerant discharge passage means of low heat conducting material connectingsaid refrigerant discharge passage with said secondary refrigerant passages in series and terminating: at said vent.

5. In a refrigerator container. for frozen foods or the like that require-freezing, zero orv sub-zero temperatures, an inner shell defining a lading compartment, an outer shell surrounding said inner shell in spaced relation thereto, means dislated by heat breaker sections and disposed in heat transfer relation with said layers of heat conducting material in succession.

6. In a refrigerator container forfrozen foods or-the like that require freezing, zero or sub-zero temperatures, an inner shell defining a lading compartment, an outer shell surrounding said inner shell in spaced non-heat-transmitting relation thereto, a ventin said outer shell, a plurality of intermediate walls made from metal ofhigh heat conductivity and disposed between said shells in spaced relation to said shells and to each other, heat-breaker means supporting said intermediate walls, insulating material disposed in the spaces between said walls and between said walls and said shells, means defining secondary refrigerant passages disposed repectively along and in heat transfer relation with respect to different ones of said intermediate walls, means disposed within said lading chamber and adjacent the top thereof todefine a primary refrigerant chamberadapted tocontainsolid carbon dioxide and having a refrigerant discharge passage, and means connecting saidirefrigerant' discharge .passagewith said secondaryrefr-igerant passages in series and terminatingin said-vent andarranged to cause downward flow and then upward flow of refrigerant gases inthe successive secondary refrigerant passages.

7. In a' refrigerator container-for frozen foods or the like that requirefreezing, zero or. sub-zero temperatures, aninner, shell defining a lading compartment, an outer shell: surrounding said inner shell in spaced relation thereto, a. vent formed in said outer shell, a. pairofintermediate walls made from metal of highiheat conductivity and disposed between saidshells in spaced relation to said shells and to each other, insulating material disposed inthe spaces be.- tween said walls and between saidwallsand said shells, means defining two secondary refrigerant passages disposed respectivel alongand in heat transfer relation with respect to different ones of said intermediatewalls, means. disposed within said lading chamber and adjacent'thetop there.- of to define a primary refrigerant chamber adapted to containsolid carbon dioxide, a refrigerant discharge passage from. said primary chamber, means of low-heat conducting material forming a connection between said: refrigerant chamber and the upper end of the inner one of said secondary refrigerant passages andconnecting the lower end of said inner passage to the lower end of the outer secondary passage to transmit gaseous refrigerant successively through said secondary passages, and means connecting theupper endof-the outer secondarypassage to said vent.

8. In a refrigerator container for frozen foods or the like that require freezing, zero or sub-zero temperatures, an inner shell defining a lading compartment, an outer shell surrounding said inner shell in spaced-relationthereto, means disposed within said lading chamber and adjacent the top thereof to define a primary refrigerant chamber adapted to contain solid carbondioxide, and having a refrigerant discharge. passage, means in said walls between said shells comprising alternate layers of insulating and. of heat conductive material, means afiordinga continuationof said discharge passage extended through saidouter shell and having sections isolated by heat breaker sections and disposed in heat transfer relation with said layers of heat conducting material in succession, andnor-mally closed openings at opposite ends of said insulation layers through which dryingair may be passed to remove condensed moisture from said. insulation layers.

9. The method of loading foods and the like for transportation infrozen or sub-zero condition which consists in loading the food: or the like into a plurality of containers each containing a supply of solid carbon dioxide adapted upon sublimation to escapefrom vents provided on the individual containers, placing such containers in side by side relation in a freight car and in spaced relation to the walls of the freight car, supporting a perforated distributing pipe about the perimeter of the group of containers, and connecting the vents of said containers to'such distributing pipe to thereby distribute the sublimated carbon dioxide gas about the space between said containers-andthe walls-of the car.

10. The method of loading foods and the like fortransportation in frozen orsub-zero condition which consists in loading the food or the like into a plurality of containers each containing a supply of solid carbon dioxide adapted upon sublimation to escape from vents provided on the individual containers, placing such containers in side by side relation in a freight car and in spaced relation to the walls of the freight car, supporting a perforated distributing pipe about the perimeter of the group of containers, connecting the vents of said containers to such distributing pipe to thereby distribute the sublimated carbon dioxide gas about the space between said containers and the walls of the car, and blowing insulation material into the space between said containers and the walls of said car.

11. The method of loading foods and the like for transportation in frozen or sub-zero condition which consists in loading the food or the like into a plurality of containers each containing a supply of solid carbon dioxide adapted upon REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,864,259 Small June 21, 1932 1,870,685 Lockwood Aug. 9, 1932 1,895,971 Carpenter Jan. 31, 1933 Voltz Jan. 2, 1934

Non-Patent Citations
Reference
1 *None
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2508384 *Sep 8, 1943May 23, 1950Us Sec WarMethod and means for automatic tracking and/or ranging
US2677245 *Sep 18, 1950May 4, 1954Edmondson Benjamin FApparatus for utilizing solid refrigerants
US2812643 *Mar 1, 1955Nov 12, 1957Worschitz FedericoContainer
US3359746 *Aug 23, 1965Dec 26, 1967Mihalich Gilfert MMethod of preserving frozen material
US3864936 *Jan 16, 1974Feb 11, 1975Burger Eisenwerke AgContainer for shipping perishables
US3906744 *Nov 12, 1973Sep 23, 1975Kardel Prod CorpPassively cooled fluid storage apparatus
US4704876 *Aug 12, 1986Nov 10, 1987Hill Ralph PCryogenic refrigeration system
US5423193 *Mar 23, 1994Jun 13, 1995Claterbos; John K.Low-maintenance system for maintaining a cargo in a refrigerated condition over an extended duration
US5555733 *Dec 8, 1995Sep 17, 1996Claterbos; John K.Low-maintenance system for maintaining a cargo in a refrigerated condition over an extended duration
US6131404 *Jun 18, 1999Oct 17, 2000H & R Industries, Inc.Insulated container
US7451614Apr 1, 2004Nov 18, 2008Perlick CorporationRefrigeration system and components thereof
EP0711965A2 *May 1, 1989May 15, 1996SAIA, Louis, P., IIIPortable self-contained cooler/freezer apparatus for use on common carrier type unrefridgerated truck lines and the like
WO2000000776A1 *Jun 18, 1999Jan 6, 2000Norsk Hydro AsMethod and container for transporting or storing goods, in particular food products in a frozen and/or chilled state
WO2005082047A2 *Feb 22, 2005Sep 9, 2005Daniel M AragonTemperature controlled container
Classifications
U.S. Classification62/62, 62/DIG.130, 62/56, 62/239, 62/DIG.100, 62/385, 62/371
International ClassificationF25D3/12
Cooperative ClassificationY10S62/01, F25D3/125, Y10S62/13
European ClassificationF25D3/12B