US2090454A - Refrigeration apparatus - Google Patents

Description

Aug. 11, 1937.

W. G. MAYER l 3?.,090Af54V REFRIGERATION'APPARATUS 3 Sheets-Shag# 1 WITNESSES Aug. 17, 1937.- w. G. MAYR ,(390,1454A REFRIGERATION APPARATUS misa-nay 4. 41951 5 sheets-sheet 2 Aug. 17, 1937.

W. G. MAYER REFRIGERATION APPARATUS 5 'Sheets-Sheet 3 Filed May 4, 1 9 1` 'bananas n INVENTOR @n l1 adm/MVL WITNESSES .ZL/JM Patented Aug. 17,1.9'37

PATENT OFFICE REFRIGERATION APPARATUS William G. Mayer,

Pittsburgh, Pa., assignor, by

mesne assignments, of one-half to Adico Development Corporation,

York,

poration of New New York, N. Y., a cor.. and one-half to International Carbonio Engineering Company, Wilmington, Del., a corporation of Delaware Application May 4, 1931, Serial No. 534,' 121 8 Claims.

This invention relates to the preservation of perishable materials, and more particularly to the refrigeration of vehicles by means of solid carbon dioxide.

Ordinary water ice as a refrigerant for vehicles,

such 4as trucks, carrying foodstuffs is not satisfactory, for various reasons. Chief among these are the large bulk and welght of ice and brine which must be carried, and the rather limited cooling effect and refrigeration period available. Also, the refrigerating effect is quite restricted.

The advantages of solid carbon dioxide, e. g., in the form of so-called snow or ice, are well known. Its temperature, is about -115 F., and

it does not melt, but sublimes. It thus provides greater refrigerating possibilities than water ice, and it eliminates the collection of liquid with its attendant disadvantages. In general 1 pound of solid carbon dioxide is capable of the same refrigerating effect as about pounds of water ice. Thus lower temperatures, with better preservation of foodstuffs, are possible, and pay loads and route lengths may be increased. Furthermore, solid carbon dioxide does not require the brines needed with water ice, so that this source of non-pay weight, and the corrosion due to brine, are eliminated.

These properties render solid carbon dioxide an ideal refrigerant, particularlyfor vehicular transportation of perishables. tially more expensive weight-for-weight than water ice; gaseous carbon dioxide formed on evaporation may exert an injurious effect on some gas with its load, as Well as providing for temperature control. The constructions, whether vehicular or stationary, not achieved these ends satisfactorily.

It is among the objects of this n fvention toxprovide a refrigerating unit for use with solid carbon dioxide which is compact, sturdy, eicient, affords maximum 'refrigerating eiect, in which the rate of heat transfer can be adjusted over a wide range, which eliminates contactof CO2 gas with the refrigerated materials, and utilizes the gas given off by evaporation -o f Ythe lsolid carbon difoxide i'.oaid in therefrigeration.: `Other objects land.mirentaseswill .appear hereinafter.

The apparatus provided by the invention com- However, it is substanavailable'heretofore have now in use,

(Cl. (i2-91.5)

prises a suitable .refrigerator compartment in which there is disposed a container for solid carbon dioxide. Surfaces of the container are exposed to the compartment, and it is provided with means for increasing the normal rate of heat transfer between the compartment and the refrigerant, which most suitably takes the form of a-base plate provided with fins. Means are provided also for controllingthe rate of heat transfer, and thus the degree of refrigeration, which in the preferred embodiment Vincludes means for increasing or decreasing the radiating area of the solid CO2 relative to the compartment. The construction is such that leakage of substantial 15 amounts of gaseous carbon dioxide into the compartment is prevented, this gas being preferably led into the insulated vwalls of the compartment Through these means I accompanying drawings, Fig.'1 is a fragmentary 2 side elevation of a truck having a refrigerated body compartment embodying the invention,

parts being broken away for clarity of illustration; Fig. 2 an enlargedperspective view of the carbon dioxide container shown in' Fig. l; Fig. 3 a perspective view of an insulating pad for use with the container of Figs. 1 and 2; Fig. 4 a cross sectional View of the compartment and unit shown in Figs. 1 and 2; Fig. 5 a plan View of the unit taken on line V-V, Fig. 4; and Fig. 6 a plan view of the cover of the unit.

Referring. to Figs. l to 6 a truck chassis -i is provided with a body A2 having double Walls 2a' filled with suitable heat insulating material 3, such as the fibrous insulators now commonly used, for instance kapok or balsa wool.

A container for solid carbon dioxide projects into the refrigerating `compartment thus formed, preferably through its top, as shown in Figs. l and 4, and in order to provide good heat transfer between its container refrigerant and the compartment, the container is formed of a metal Vmensions are such as to provide for the insertion of the Astandard solid blocks of carbon dioxide l or multiples or uniform fractionsthereof.

'I'he container is preferably provided with means for increasing its normal heat radiating capacity, such as fins. Most suitably this is accomplished by the use of a base plate provided with fins. The preferred embodiment, as shown in the drawings, comprises a metallic base plate 5 connected to the side. walls and projecting laterally therebeyond. Various types of heat conducting fins may be used, the embodiment shown comprising V-shaped fins formed by bending sheet metal to form corrugated strips 6. On the'upper side of base 5 these are connected to the portions which extend beyond the container Walls, and are Welded to the latter. They also extend entirely across, and are connected to,

the lower side of plate 5. This construction increases the heat conducting area, as compared with ordinary flat vand straight fins, and it-pro- Vides channels for circulation of air. Preferably base 5 and strips 6 are provided with holes l. and slots 8 are cut in plate 5 and strips 6, to increase the circulation of air over the side walls. This construction, with metallic connection between /the ns, side walls and base, further enhances the heat transfer.

In order to render the container proof against leakage of 'CO2 gas into the compartment, the

side walls and base are preferably welded to- The construction thus provided is adapted to `eiiciently refrigerate the compartment, but because regulation of temperature is desirable, either to prevent freezing of the materials carried, or to keep them at a desired temperature,

and also to reduce CO2 consumption, means are provided for regulating the compartment temperature to a desired predeterminedvalue, by regulating the rate of heat transfer between the compartment and the solid carbon dioxide.

In accordance with the invention temperature control is effected by vertical adjustment of the container, or of the CO2 refrigerant, or both. As shown in Fig. 2, side plates 4 are provided with a plurality of horizontal rows of holes I0 for connecting the container to side walls 9 of the hatchway by means of screws. ner the container may be adjusted in the hatch- Way to ,-vary the vertical exposure x, Fig. 4, -of its side Walls, thus increasing or decreasing the 5 refrigerating effect as need be, both by altering the Aexposed heat conducting side wall area, and

by varying the relative are'a of solidCOz exposed to the compartment through the container side walls. By the use of a plurality of rows Vof stag-l gered holes IG this adjustment is provided for, andleakage of gas between the container and hatchway walls is minimized. y f

Further control is afforded also by means of insulating pads placed under the blocks I'I of solid carbon dioxide. Such pads reduce the rate of heat transfer through the base plate-by eliminating direct contact ofthe blocks II with` plate 5. They also -reduce the area of CO2 exposed to the compartment through the side walls. A particularly suitable insulating pad is shown inFig. 3. vIt comprises a hollow gas-tight boxlike structure I2 formed of metal, and to increase its strength there is disposed Within it a cor-` rugated metallic reinforcing member I3. This adds strength while retaining the heat-insulat- InV this mani f, material, but is cork or thetlike,

justment.

the hatchway walls, this valve being adjustable `,to maintain the pressure at a desired predetermined` value, for example 5 to 15 pounds. This CO2 gas is quite cold, and while it may be relieved to the atmosphere, it is preferred to use it as an additional refrigerant.. For this purpose valve I8 opens into the insulation space between side walls 2a, and circulates through insulation 3 surrounding, thus cooling the compartment walls. In order to permit free circulation, the body structural lmembers I9 are provided with holes 20 as need be. The gas finally escapes to the atmosengage catches I 'I on hatchway side walls 9.

The containers may be of any desired size, depending upon the sizel of the compartment, the length ofhaul, and the degree of refrigeration needed. They may be adapted to take a single, or a plurality of blocks, disposed horizontally, or stacked vertically.

Where the containers are to accommodate more than one block of carbon dioxide, it is preferable to secure partition plates 2l therein to form an individual compartment for each block,

softl'iat as the blocks evaporate they will stay more or less in place and not shift about.

In the use of the refrigerator unit thus provided the container is adjusted to provide an exposed vertical distance a: such as to maintain the desired temperature in the compartment. This may be done when assembling the vehicle, the builder knowing from the size of the compartment and the container capacity what exposure to provide in order to obtain any desired temperature. 'It has been found that, in general,l

five pounds per square' inch gas' pressure in the container is suiiicient to retard evaporation satisfactorily, and pressures up to 15 pounds do not result in any appreciably greater retardation. In order to prevent extreme pressure within the chamber, should the valve fail to function, latches.

I6 are resilient enough to allow the gas to escape past gasket I5 after it has reached a pressure of a few pounds above that for which the valve is set.

Solid carbon dioxide blocks are placed in the container, the cover is set in place, and the latches sprung under the catches, thereby tightly sealing the chamber. As evaporation of the CO2 proceeds to a point where the gaspressure within the chamber exceeds the pressure valve I8 is set for,

Y the excess pressure is relieved through the valve and the gas circulates through insulation 3 about all parts of the walls, and still further aids in. cooling the compartment.

In case insulation 3 is not a fibrous or loose valve I8 may open into the outside atmosphere. Where meat or contributing furtherl and the like, which are improved by carbon dioxide gas, are carried the valve may open into the compartment to allow the gas to come into direct contact with such materials.

If it is desired to raise thetemperature in the compartment higher than that initially provided for, the 'container may be raised by removing the screws from holes Ill and elevating it, or one or more pads of the type described may be placed under the block to separate it from direct contact with the base radiation plate. By having a number of such pads of various thicknesses to select from, a wide range of temperature control will be made possible. Actual tests have shown that by varying thevertical position of the container and by using insulating pads, a temperature range of between 40? F. below zero to 15 F. above can be obtained.

For large,vehicles, `and for lspecial purposes,`

any desired number of the units may beused, and they may be disposed otherwise than through the roof, where this appears to be desirable. construction described is preferred, however, be-

v cause the interior of the units are readily acces- Aprevent leakage of vgaseous carbon dioxide into the compartment,

sible through the roof, the units do not interfere materially with the insertion and removal of goods in the compartment when the units are in this position, and because `warm air tends to rise to the roof.

The unit provided by `this invention requires but a small amount of space in a refrigeration compartment', as compared with water ice units, which results in providing more space for food; and larger pay loads. Furthermore, as the unit is relatively small, and is preferably constructed of a light metal, such as aluminum, lighter trucks can be used, which decreases the initial vehicle cost, and its upkeep, and also increases the area of the district that can be served by a single .ve'

hicle.y As the container and radiation plate ,extend such a short distance into the refrigeration compartment, they interfere but little with eilicient packing of the latter with foodstuffs. By having'the gas pass into the insulation the carbon dioxide is made to serve twice, first by means of the radiation plate, and second by keeping the walls cold.

According to the provisions of the patent statutes, I have explained the principle and mode of operation of my invention and have illustrated and described what I now consider to represent its `best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. An apparatus for preservation of perishable materials comprising the combination of arefrigerating compartment for said materials, a

1container for solid carbon dioxide refrigerant projecting downwardly through the compartment roof and having a base. and side walls of metal of high thermal conductivity connected to substantial amounts of means for maintaining gaseous carbon dioxide in the container under a predetermined pressure, said base having metallic heat conducting means connected thereto and extending laterally of the container walls, and means for adjusting said solid ycarbon dioxide vertically. of the compartment to control the temperature of said materials by regulating the rate of heat transfer between the compartment and refrigerant.

The-

2. An apparatus for preservation of perishable I materials comprising the combination of a refrigerating compartment for said materials provided with a hatchway through the roof, a container for solid carbon dioxide refrigerant pro-v jecting into said compartment through and ver-y tically adjustable in said hatchway, said container having side walls and a base plate formed of metal of high heat conductivity and having Y its side Walls cooperating with the hatchway to tainer for solid carbon dioxide refrigerant prov jecting into said compartment through and vertically adjustable in said hatchway, said container having side walls and a base plate formed v of metal of high'heat conductivity and having its side walls cooperating with the hatchway to preventleakage of r'substantial amounts of gase- -ous lcarbon dioxide into the compartment, said base plate extending laterally beyond said side walls and. being provided with corrugated metal plates forming openchannelV-shaped heat-conducting fins, a removable closure for said hatchway, said container retaining gaseous carbon dioxide gas under pressure in the container, and `a relief valve associated with said container for pressure.

maintaining said gas under a predetermined 4. `An apparatus for preservation of perishable materials comprising the combination of a refrigerating compartment for said materials bounded by double heat insulated walls and provided With a hatchway through the roof, a container for solid carbon dioxide refrigerant pro'- jecting'into said compartment through and vertically adjustable in said hatchway, said container having side walls and a base plate formed of metal of high heat conductivity and having its side walls cooperating with the hatchway to prevent leakage of substantial amounts of gaseous carbon dioxide into the compartment, said base plate extending laterally beyond said side walls and being provided with corrugated metal plates forming open channel V-shaped heat-conducting fins, a removable closure for said hatchway, said container retaining gaseous carbon 'dioxide under pressure in the container, a relief valve connect-v ing'said container with the space between said double walls, means for' varying the relativearea of solid carbon dioxide exposed'fto the compartment through the walls to further regulate the temperature within said compartment, and means for increasing air circulation over said heatits side walls cooperating with the hatchway to l prevent leakage of substantial amounts of gaseous 5 forming open channel V-shaped heat-conducting thermal conductivity associated to prevent leak- 5 iinsa removable closure for said hatchway, said age of substantial amounts of gaseous carbon container retaining gaseous carbon'dioxide under dioxide into the compartment, a removable gaspressure, and a relief valve associated vwith said tight closure for the container for introduction container whereby to maintain said pressure at of solid carbon dioxide into the container and 1() a predetermined point and adapted to'permit the for maintaining gaseous carbon dioxide therein 10 gas in excess of the pressure desired to escape under pressure, the base of said container havinto said double Walls in order to further cool ing on the side exposed to said compartment l thecompartment, means-for insulating the solid increased heat exchanging area. a relief Valve carbon dioxide from the container in order to associated with the container for maintaining further regulate the temperature Within said resaid gas under a predetermined pressure therein, 15

frigerating compartment, and means for increasand means for adjusting said solid carbon diing'air circulation over said heat-conducting ns. oxide vertically of the compartment to control l6. An apparatus for` preservation of perishable the temperature of said materials by regulating materials comprising the combination of a rethe rate of heat transfer between the compartfrigerating compartment for said materials, a ment and refrigerant. i 20 container for solid carbon dioxide refrigerant 8. An apparatus for preservation of perishable projecting downwardly into said compartment materials comprising the combination of a refrom its roof, said container having side Walls frigerating compartment for said materials, a and a base plate formed of metal of high heat f container for solid carbon dioxide refrigerant conductivity associated to prevent leakage of projecting downwardly through the compartment 25 Isubstantial amounts of gaseous carbon dioxide roof and adjustable vertically of the compartinto the'compartment, said base plate being proment, the container having a base and side walls vided on the side exposed lto said compartment of metal of high thermal conductivity connected with means providing increased heat exchanging to prevent leakage of, substantial amounts of surface, and one wall of the container being progaseous carbon dioxide into the compartment, 30 .vided with a removable gas-tight closure for inmeansfor maintaining gaseous carbon dioxide troduction of solid carbon dioxide into the conin the container under a predetermined pressure, tainer'and for retention of carbon dioxide gas said base having on the surface exposed to said therein, and means for adjusting said solid carcompartment increased heat exchanging surface,

bon dioxide vertically of the compartment to and means for adjusting said solid carbon dioxide control the temperature of said materials by regvertically of the compartment to control the temulating the rate of heat transfer between ,said perature of said materials by regulating the rate compartment and refrigerant. of heat transfer between the compartment and 7. An apparatus for preservation of perishable refrigerant.

o materials comprising the combination of a refrig- WlLLIAM G. MAYER. `40

carbon dioxide into the compartment, said base plate extending laterally beyond said side Walls and being provided with corrugated metal plates erating compartment for said materia1s,a con- CERTIFICATE 0F GORRECTIO.

tainer for solid carbon dioxide refrigerant assofprojecting downwardly therein, the container having aV base and side walls of metal of high August-17, '1957.

cated with the roof of said compartment and l wILLIAu c, MYER.

Itis hereby .certified that error appears in thelprinted specification ofthe above nunbered patentorequiring correctionas follows: Page 2, second A colunm, line 51, strike out "engage catches 1T on'hatchway'sidewa11s 9" and insert insteadthe syllable andwords phere through the cracks in the body walls; and that the said Letters Patent should be read with this correction therein that the `same may conform to thev record of the case inthe Parana office.; o signes and sealed this 19th day `or october, A. in. 1957. f

lHenry Van A rsdale (Seal) i Acting Commissioner of Patents.

, prevent leakage of substantial amounts of gaseous carbon dioxide into the compartment, said base plate extending laterally beyond said side Walls and being provided with corrugated metal plates erating compartment for said materia1s,a ccn- CERTIFICATE F GORRECTIO.

tainer for solid carbon dioxide refrigerant assofprojecting downwardly therein, the container having aV base and side walls of metal of high August-17, '1957.

cated with the roof of said compartment and l 5 forming open channel V-shaped heat-conducting thermal conductivity associated to prevent leak- 5 finsa removable closure for said hatchway, said age of substantial amounts of gaseous carbon container retaining gaseous carbon'dioxide under dioxide into the compartment, a removable gaspressure, and a relief valve associated vWith said tight closure for the container for introduction container whereby to maintain said pressure at of solid carbon dioxide into the container and 1() a predetermined point and adapted to'permit the for maintaining gaseous carbon dioxide therein 10 gas in excess of the pressure desired to escape under pressure, the base of said container havinto said double Walls in order to further cool ing on the side exposed to said compartment l thecompartment, means-for insulating the solid increased heat exchanging area. a relief Valve carbon dioxide from the container in order to associated with the container for maintaining further regulate the temperature Within said resaid gas under a predetermined pressure therein, 15

frigerating compartment, and means for increasand means for adjusting said solid carbon diing'air circulation over said heat-conducting ns. oxide vertically of the compartment to control l6. An apparatus for` preservation of perishable the temperature of said materials by regulating materials comprising the combination of a rethe rate of heat transfer between the compartfrigerating compartment for said materials, a ment and refrigerant. l 20 container for solid carbon dioxide refrigerant 8. An apparatus for preservation of perishable projecting downwardly into said compartment materials comprising the combination of a. refrom its roof, said container having side Walls frigerating compartment for said materials, a and a base plate formed of metal of high heat f container for solid carbon dioxide refrigerant conductivity associated to prevent leakage of projecting downwardly through the compartment 25 Isubstantial amounts of gaseous carbon dioxide roof and adjustable vertically of the compartinto the'compartment, said base plate being proment, the container having a base and side walls vided on the side exposed lto said compartment of metal of high thermal conductivity connected with means providing increased heat exchanging to prevent leakage of, substantial amounts of surface, and one wall of the container being progaseous carbon dioxide into the compartment, 30

.vided with a removable gas-tight closure for inmeansfor maintaining gaseous carbon dioxide troduction of solid carbon dioxide into the conin the container under a predetermined pressure, tainer'and for retention of carbon dioxide gas said base having on the surface exposed to said therein, and means for adjusting said solid carcompartment increased heat exchanging surface,

bon dioxide vertically of the compartment to and means for adjusting said solid carbon dioxide control the temperature of said materials by regvertically of the compartment to control the temulating the rate of heat transfer between ,said perature of said materials by regulating the rate compartment and refrigerant. of heat transfer between the compartment and 7. An apparatus for preservation of perishable refrigerant.

o materials comprising the combination of a refrig- WlLLIAM G. MAYER. `40

wILLIAu c.y MYER.

Itis hereby .certified that error appears in thelprinted specification .vof'the above nunbered patentrequiring Aeorrect'ionas follows: Page 2, second A colunm, line 51, strike out "engage catches 1T on'hatchway'sidewa11s 9" and insert insteadthe syllable andwords phere through the cracks in the body walls; and that the said Letters Patent should be read with this correction therein that the same may conform to thev record of the case inthe Patent offres.; a signes and sealed this 19th day `or october, A. in. 1957. f

lHenry Van A rsdale (Seal) i Acting Commissioner of Patents.

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