US2203591A - Flexible refrigerating package production - Google Patents

Description

June 4, 1940. c, F, BROWN 2,203,591

FLEXIBLE REFRIGERATING PACKAGE PRODUCTION Filed April 25. 1938 Patented 4June 4, 1940 FLEXIBLE REFRIGERATING PACKAGE PRODUCTION Claude F. Brown, Chicago, lll. Application April 25, 1938, serial No. 204,145

` 8 Claims.

h rl`his invention relates to a process of forming a flexible refrigerating package capable for use for maintaining articles in a refrigerated condition in much the same manner that solid carbon dioxideso-called Dry Icemaintains such perishable and/or meltable products in non-perishable and/or non-meltable condition, respectively, for portable delivery over reasonable periods of time.

a Dry Ice substitute, as it were, which will be less expensive and which will be devoid of certain well known objections inherent to the use of Dry Ice for the aforesaid purposes.

The chief feature of the invention consists in enclosing within a waterproof, flexible container, such as a sack of bean bag character, as it were, a brine solution, sealing the container and freezing the brine to solid form in said container.

It has been experimentally determined that substantially double the weight of solid brine has a low temperature maintaining capacity substantially equivalent to that of a single weight of solid carbon dioxide within its temperature limits; or in other words, itsrefrigeration value or capacity is but half that of Dry Ice within said limits for substantially equal weights.

The portable Dry Ice delivery service has demonstrated that for retail delivery from small stores to the consumer, the ratio of effectiveness is approximately one to five, due to the sublimation loss factor and is dependent upon dependable delivery of the Dry Ice to the retailer. This dependable delivery means in other Words, the retailer daily must anticipate his potential requirements in order to minimize his sublimation losses, otherwise, Dry Ice refrigeration for portable delivery is prohibitive Iat the present price for saidrefrigerant. l 40 The present invention, therefore, has the peculiar advantage that there is substantially no loss in material and that the material may be rapidly and economically brought to a refrigerating condition for use as a refrigerant equivalentA The chief object of this invention is to produce (Cl. 6Z-1) v der extreme low pressures, wherefore the 10,000

B. t. u. gure is here given-the ratio that two pounds of brine ice bears to 1 k. w. h.'of energy is that therequivalent two pounds of brine ice costs, exclusive of the water and salt cost which is practically negligible, 1,4, of the cost of a k. w. h.

of energy, which in many instances is` 11/2 cents-15 and throughout the country averages about 2 cents for power purposes in industrial establishments, such as ice cream plants. In other words, assuming a cost of 2 cents per k. w. h. of energy, which is above the average minimum rate charged household consumers of energy for mechanical refrigeration in many localities, fthe' cost of obtaining the refrigerating capacity. in two pounds of brine ice is approximately .05 of 1 cent as compared with the 3 cents for Dry Ice before mentioned, except there must be added to this .05 of a cent the cost of the container and the cost of the brine.

The container, it is estimated, costs approximately 1/4 cent so that the total cost of the equivalent brine ice refrigerant capacity as compared to Dry Ice, if the latter is applied bare to a product for refrigerating the same, is approximately 1% cents as to 3 cents These approximate figures, as stat` d, are given by way of example only to illustrate re economy of the refrigerant of the present intention as compared with Dry Ice as a refrigerant, assuming no loss in storage or handling of either material.

If it is assumed that one quart of ice cream is to be held in a frozen condition for four to six hours, the same will require ,/2 pound Dry Ice and similarly there will be required approximately 1 pound of brine ice to effect the same refrigeration under the same conditions, which is requiredl for use with the usual insulated package conditions today applying to portable delivery service.

Merely by way of illustration, certain specific materials are hereinafter mentioned, although it is to be understood that other materials are I one example of the refrigerating unit embodying the invention and Fig. 2 is a sectional view taken 'on line 2 2 of Fig. 1 and in the direction of the arrows.

The example illustrated in the drawing includes a layer of kraft paper I0 having an interior leakproof coating II. The fold is indicated at I2, the side seam at I3, the bottom seal at I4 and the top seam at I5. The eutecticmaterial, such as of brine character, is shown as ice I6 in Fig. 2 and substantially lls the container.

One type of package, as previously suggested, is of bean bag character so far) as the form is concerned. It may, however, be of any desired bag character.I It must, however, be of waterproof character and must be flexible, within those degrees of waterproofing and flexibility neces'- sary to successfully effect the invention.

The brine may be of any suitable concentration. One example is herein set forth. A 20% brine freezes to solid brine ice and has a efutectic point of zero degrees F. 20% brine includes one gallon water, which is approximately 8.3,p0unds water and approximately 2 pounds sodium chloride. Whenever lesser bulk is desired or calcium chloride is available as a cheaper source of material, such as is incident to the production thereof as a waste product from other industries, a lesser amount of calcium chloride may be utilized instead of sodium chloride.

A relatively cheap container which may [be discarded by the ultimate consumer of the perishable or meltable merchandise, is\a waterproof flexible paper bag, as stated. An example of such abag, for instance, is one made of 50 1b. kraft paper having a small percentage by Weight of glycerine incorporated in the paper stock because it is advantageous to utilize such a type of paper, although it is not absolutely essential to the practicing of the invention since any paper stock having flexibility at low temperatures will be satisfactory.

This kraft paper is suitably wa-terproofed and in the present example, the inside surface of the bag is Waterproofed by one face of the paper carrying a coating. One satisfactory coating is that which includes 20 lbs. of chlorinated rubber per ream. This again, as stated, is only given by way of example. Such a material readily lends itself to sealing by heat, although sealing by heat is not essential to the practicing of the process. There are other waterproofing materials of resinous, cellulous and rubber or rubber like character that are also satisfactory for use. Merely by way of example as to the equivalent containers available, a flexible relatively thin rubber like sack or bag that will properly function under low temperature conditions would serve equally as well, although as stated, the container following use of the product is intended to be discarded and the cost of such a properly compounded rubber container exceeds that cost of a paper contained `as previously described specifically hereinbefore.

One relatively simple form o'f bag, as stated, is of bean bag character. A sheet olf the proper size of the glycerine impregnated paper having the waterproof coating thereon, is folded so as to form a tube. The seam is sealed by hea-t and pressure. This is because the material mentioned is of thermoplastic character. If the Waterproof coating is of other character, either suitable sealing mediums' or treatments may be employed to effect the seal.

Following formation into tubular form, one end of the tube is similarly sealed, then the tube is filled approximatelyhalf full withliquld brine of the character described. The opposite end of the tube is then sealed. The resulting partially lled sack is laid on its side and subjected to low temperature, which forms in the sack th solid brine or brine ice.

The choice of bag forming` material is dictated not only by the item of cost and availability of materials but is also controlled by the fact that in the formation of brine ice, crystals are formed and the container must be puncture proof so far as said-crystals are concerned. This. packaged brine ice at or.below the eutectic point is then available for use to prevent melting of ice cream, sherbets and the like and other articles whose eutectic point `is hi'gher and for the preservation of perishable articles.

It will be obvious from the foregoing that the only loss sustained in storage of this type of refrigerant is its loss of heat capacity by absorption of heat and this can readily be renewed by refreezing. In the manufacture of ice cream there is usually available a hardening'room at a temperature of zero to 20 below F. and when once the brine ice is formed and the packaged brine ice is stored in the hardening room or in a room at an equal temperature, the loss of refrigerating capacity is prevented. With the case'of Dry Ice, however, there is a loss due to sublimation and any recovery thereof is more expensive than initial production, and is beyond the facilities of the average ice cream manufacturer. 'I'he reason for` this loss is that Dry Ice sublimates at approximately 110 below zero F., andthe range of present day mechanical equipment is such that such temperatures cannot economically be maintained for storage purposes; whereas, the holding temperature for solid brine ice can be maintained very economically.

It will be readily apparent that the retailers can be supplied with partially lled packages of liquid brine -and the same conditioned by the retailer to a package of solid brine ice. The equipment necessary for such processing is relatively inexpensive and is of the general character of the present household mechanical refrigerator. In larger communities it is more economical to fabricate the refrigerant ready for use in the ice cream manufacturing establishments or the ice manufacturing establishment, and without any special additional equipment.

While the invention herein has been described as utilizing a, brine material, it is to be understood any other suitable material may be employed. Such material, however, must have a low temperature eutectic point. Other materials are alcohol, glycerin, ethyl glycol and the like.

The container correspondingly must .not only be waterproof but resistant to the passage of the ice forming material employed. In other Words, the coating is resistant to ice forming material employed, if the container is of paper or other equivalent stock not normally resistant to the passage of such ice forming material therethrough.

The term flexible as used herein and in the claims is intended primarily to designate a container for a freezable solution which container during the freezing operation will automatically change shape as required or necessary, so that rupture, leaking or permanent distortion of the container does not result in such freezing action incident to the volumetric increase in the formacal condition of the object can be obtained' and/ or maintained.

The full nature of the invention has been described in great detail in the foregoing description. The same, however, is to be considered as illustrative only and not restrictive in character.

'I'he several modifications described herein as well as others which will readily suggest themselves to persons skilled in this art, all are considered to be within the broad scope of the invention, reference being had to the appended claims.

The invention claimed is:

1. The process of forming a refrigerating bag structure including forming a `flexible, ruptureand leak-proof bag of relatively light material and with an open mouth, partially filling the same through the mouth with low temperature point eutectic liquid, the bag material being proof against liquid passage therethrough, sealing the liquid in the bag, and then freezing to form cryohydrate ice, the bag structure merely flexing without rupture during the freezing step.

2. A refrigerating bag structure including a flexible, relatively rupture and leak-proof material arranged in bag formation and a low temperature point eutectic material permanently sealed therein, the bag formation permitting eutectic material expansion without rupture when refrigerated to ice, and preventing leakage therefrom when reduced to liquid form.

3. A structure as dened`by claim 2. characterized by the bag being formed of a flexible paper layer with an inner rubber-like material layer coextensive therewith and united thereto substantially throughout the contacting surface areas thereof.

4. A structure as dened by claim 2, characterized by the bag formation being of bean bag form.

5. A structure as dened by claim 2, characterized by the water volume being less than that of the sealed bag volume and in an amount such that the resulting ice volume therefrom is substantially the same as the volume of the sealed bag.

6. The process of forming a refrigerating unit which includes the steps of partially filling a bag with a liquid capable of being formed into ice, the bag being characterized by its construction of material including relatively light paper stock and a layer of material thereon rendering said stock proof against the action of such liquid, said bag being flexible, and proof against rupture as a result of repeated handling or flexing during freezing and thawing, sealing the liquid in the bag to form a leak-proof unit, and freezing the liquid in the bag to a substantially solid ice condition.

7. A refrigerating unit comprising a bag formed of relatively light paper stock, a layer of material on the stock which is unaffected by the action of a liquid to be sealed therein, and a liquid material capable of forming ice permanently sealed in saidbag, the bag being flexible and substantially proof against leakage and rupture as a result of repeated handling or flexing during freezing and thawing of said liquid to permit the bag to iiex without rupture, leakage or permanent deformation during the cycle of refrigeration of the liquid to ice and return to fluid form.

8. As a new article of manufacture employed in performing the process of forming a refrigerating. unit, a bag structure of flexible paper having an inner layer of material which is unaffected by the chemical or physical action of a refrigerant when permanently sealed therein when such liquid is refrigerated to ice and then allowed to thaw, the bag structure being characterized in

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