US 2803115 A
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0, 1957 J. c. SHEPHERD 2,803,115
REFRIGERANT nowovaa PACKAGE Filed July 17, 1953 I5 Sheets-Sheet 1 srARcH #07 WA TE]? 5:. wmv
INVENTOR- JOHN G. SHEPHERD ATTORNEY WM h 1957 J, c. SHEPHERD 2,803,115
REFRIGERANT nowovaa PACKAGE Filed July 17,1953 3 Sheets-Sheet 2 Eig- .ZU.
INVENTOR. JOHN C- SHEPHERD ATTORNEY Aug. 20, 1957 J. c. SHEPHERD 2,803,115
REFRIGERANT HOLDOVER PACKAGE Filed July 17. 1953 3 Sheets-Sheet 3 UINVENTOR. E W
JOHN a. SHEPHERD A TTORNEY United States Patent REFRIGERANT HOLDOVER PACKAGE John C. Shepherd, Monrovia, Calif.
Application July 17, 1953, Serial No. 368,748
Claims. (Cl. 62-1) This invention relates to an improved refrigerant which does not leak water after its temperature rises above the eutectic point. More specifically this invention relates to a refrigerant holdover package which is suitable for re-use, i. e., the refrigerant may be repeatedly frozen and thawed.
For many purposes, water ice is an undesirable refrigerant solely because it melts into water at the comparatively low temperature of 32 F. Once it turns to water, it flows away from the goods so that it is no longer present to refrigerate them; still worse, it often spoils the goods being refrigerated and damages or destroys the shipping container in which the goods are packed. Except for this property of melting, water ice is an excellent refrigerant, because it has very high specific heat and a very high heat of fusion.
I have solved the problem caused by the melting of water ice and have devised a refrigerant that incorporates water, along with its attendant advantages, but does not liquefy when its temperature exceeds its freezing or eutectic" point; i. e. that temperature where a quantity of heat energy is transferred without any resultant change in temperature, due to a change of state. The quantity of heat consumed during this change in state is commonly known as the heat of fusion."
Water cannot be packaged satisfactorily for use as a refrigerant, because, if the container is ruptured, the water will flow out when it is melted. Various materials have been employed in attempts to hold water. For example, a. packaged refrigerant utilizing sawdust and water, has been proposed, but if the container was ruptured, or if it was provided with perforations in order to permit the sawdust to absorb the water, then the sawdust would leak water, especially when it was subjected to any pressure. Therefore, packaged refrigerants had heretofore proved unsuccessful, because once there was a hole through the package, water would leak out.
In other patent applications, Serial No. 363,155, filed June 22, 1953, and Serial No. 363,186, filed June 22, 1953, I have presented a greatly improved refrigerant utilizing nonleaking gels. These gels are usually composed of starch modified by borax and sometimes by an aldehyde, and, in some cases, with materials which modify the eutectic point (e. g. soluble mineral salts). Although these gels have provided a very good solution to the problems mentioned above, their use led to certain other problems. While they did not leak water when they thawed, and while they lasted a considerable length of time when made according to certain formulas, their life was limited by certain factors. For one thing, they tended to dry out when exposed to surrounding dry air, and in time this drying action would render the gel useless, long before it became an xerogel. At other times, in moist air, the coldness of the gel in its frozen stage caused condensation from the atmosphere, and this condensed moisture would often react with the gel to weaken its structure and sometimes break it down by making it too watery. Another difficulty with starch gels in certain uses, was that they tended to add water to goods which were water-absorbent, simply by contact.
Another difficulty with the gel refrigerants formerly used was that their shape would break down and change. Layers which were better kept separate would coalesce into larger pieces than were desirable. Shapes corresponding to the spaces between the goods would be formed, and sometimes had to be cut apart before they could be used. Furthermore, the gels would often stick to the goods or their containers, with resultant damage to either the goods or the gel or both. These gels also tended to get contaminated by foreign matter in the air or the environment. A further problem was that the gels were difficult to handle, due to the fact that each piece of gel was held together only by its own internal structure and also due to its tendency to coalesce with other pieces of gel, as well as the other effects mentioned above.
I have solved the problems which have been explained above, by providing a packaged gel refrigerant. Lest it be assumed that gel in a package is like any other type of goods in a package, it should be explained that rather astonishing and unexpected results flow from my combination, because of a novel coaction between the gel and the package. In the first place, the gel will not leak from a punctured package as will water, which will leak whether or not it be combined with sawdust or another absorbing agent. In the second place, the gel will seal the leak. If the package containing my improved gel is punctured or cut-and the cuts or punctures may be very large in areathe gel itself will seal the holes against leakage and prevent damage to the bulk of the gel by having a small portion dry out. As a result of this co action, the packaged gel is self-sealing.
The Package obviously aids the handling of the gel and enables it to maintain its original shape. Also the packaging adds considerably to the life of the gel by cutting down the exposure to air, the contamination, and the tendency to dehydrate or to absorb water. More important, when moisture is condensed from the air by the gel refrigerant, the moisture forms on the outside of the package rather than on the gel itself. Furthermore, the package itself prevents the sticking that occurred between the gel and other surfaces; the only sticking that the gel can do is in its own package where such sticking is not desirable.
Other advantages of the invention will appear in the following description, given in accordance with 35 U. S. C. 112.
In the drawings:
Fig. l is a view in elevation, somewhat diagrammatic in nature, of a waterproof transparent container being filled with a starch slurry and hot water having borax dissolved therein, to form therein a stable non-leaking gel, in accordance with the present invention.
Fig. 2 is a view in perspective, also somewhat diagrammatic in nature, showing the container of Fig. 1 being sealed at its open end.
Fig. 3 is a view in perspective, somewhat diagrammatic in nature, showing the container of Figs. 1 and 2 being pressed to distribute the material therein evenly and being punctured to let out air entrapped therein.
Fig. 4 is a view in perspective of the completed packaged refrigerant.
Fig. 5 is an enlarged diagrammatic view in section illustrating how the gel seals an opening accidentally made through the walls of its container.
Fig. 6 is a view in elevation of a modified form of container.
Fig. 7 is a view in section taken along the line 7-7 in Fig. 8 is a view similar to Fig. 7 showing the closed position of the container opening.
Fig. 9 is a view taken along the line 99 of Fig. 6.
Fig. 10 is a view in elevation of a portion of a container having a modified form of opening.
Fig. 11 is a view taken along the line 11-11 in Fig. 10, with the opening shown in its open position.
Fig. 12 is a view similar to Fig. 11 showing the opening closed.
Fig. 13 is a view in section taken along the line 1313 of Fig. 10.
Fig. 14 is a view in perspective of another modified form of the invention.
Fig. 15 is a view in perspective of still another modified form of the invention.
Fig. 16 is a view in perspective showing an early step in a method for making another modified form of package. A block of gel has been spread out uniformly on a sheet of wrapping material.
Fig. 17 is a view in perspective showing the sheet of Fig. 16 folded over with the edges open.
Fig. 18 is a view in section taken along the line 18-18 of Fig. 17, with the edges sealed.
Fig. 19 is a view in perspective of a slab of gel on a fiat container sheet.
Fig. 20 is a view showing the slab of Fig. 19 rolled up into a jelly-roll-like shape, with the ends open.
Fig. 21 is a view in elevation of the Fig. 20 container with its ends closed.
All forms of the invention comprise a package made up of gel and a container.
The gel may be a starch-borax gel of the type shown in the aforementioned copending applications, and it may have the following proportions:
Example 1 Starch 100 parts. Water Between 300 and 2,000 parts. Borax Between 13 and 100 parts.
Example 2 Starch 100 parts. Water 300 to 2,000 parts. Borax 3 to 100 parts. Paraformaldehyde /2 to 100 parts.
The gels shown above may be made by adding the borax and ungelatinized starch to relatively cool water and heating the mixture to about the boiling point, until it gelatinizes, or the gels may be made by any other suitable method. Since formulas and methods are given in the other patent applications referred to and since this application relates to combination of the gel and the package, detailed formulas are unnecessary here. In addition to starch gels, the gel-like substances made by mixing finely powdered bentonite clay with cold water may be used for some uses. So may the water mixture with cellulose gum or CMC, which is a sodium salt of carboxymethylcellulose. So may gels made from pre-gelatinized starch. However, the gel or gellike substance must be one that is capable of the selfsealing action which has been described, or full advantage cannot be taken of the invention.
Certain features of the package depend upon the use to which it is to be put. It can be made almost any shape, and the package serves to retain the gel in selected shape.
The material from which the container is made is preferably flexible and waterproof, especially when the gel is to be reusable. In such instances it may comprise polyethylene film, rubber, rubberized canvas, waterproof cellophane, vinyl plastic film, etc. Transparent containers are especially good for many uses, as observation of the gel becomes possible. Where the gel is to be used only once, and where the problem is simply that of making the handling easier, and avoiding sticking upon contact with the goods and related problems, the container may be made from a relatively inexpensive type of waterproof cellophane and may be left open at one end, so long as the gel does not come in contact with the goods. For more permanent use, the more rugged materials referred to should be used, and the package should be sealed tight. The seal may be a hermetic one, as by welding the plastic film together or may be a mechanical one.
Where a sealed package is to be used in order to produce a longer lasting product, it is possible to manufacture the gel in the container. This may be done by mixing cold water with borax and powdered pregelatinized starch or with bentonite or with cellulose gum, directly in the package. Or this may be done, as in Fig. l, where hot water, preferably containing dissolved borax, is mixed in the container 10 with a warm slurry of water and ungelatinized starch, preferably containing formaldehyde. The container 10 may simply be filled with the gelatinous liquid 11 to a predetermined level, by properly adjusting the flow of the slurry by means of the valve 12, to the flow of the hot water, through the valve 13. The valve 14 may be used to cut off the flow of the mixture.
As shown in Fig. 2, the container 10 may be sealed along the top seam 15, by means of an electrical plastic welder 16, for example. For some uses sealing is not necessary, but the life may be greatly prolonged thereby.
While the gel 11 is still warm, the package may be placed in a press 17 as in Fig. 3. There the final shape of the gel is formed, whether it be a slab or a cylinder, or whatever. Air trapped inside the container may be let out by making a small puncture 18 by a needle 19, and the pressure will force the air out. The drying of the gel 11 seals the puncture 18, as shown in Fig. 5.
Fig. 4 shows a slab type of package 20 made by the above process, where the gel 11 is encased in a container 10 of transparent polyethylene or some similar material. The flat form of this slab 20 is very useful for placing under or over such containers as frozen food boxes. The slab 20 may also be placed inside such containers. The slab 20 may be used over and over repeatedly and is practically permanent.
As Fig. 5 shows, when a puncture 18 occurs in the container 10, the gel 11 at that point becomes somewhat dehydrated over a very small surface, and forms a crusted area that prevents any breakdown of the bulk of the gel or any absorption of water by the gel 11 or loss of water from it. Due to the use of the gel 11 in the container 10, no material will ooze out of even a large hole or slit, even if the package is under a considerable pressure, unless the pressure be applied very unevenly, and then only when the pressure is far larger than that to which the container is normally exposed.
A modified form of container 30 is shown in Fig. 6. Here the edges 31 are all closed or seamed, and an opening 32 is provided for filling the container 30 with the gel 11. This opening 30 is a type that can be sealed substantially air tight by hand, but can be opened at any time by hand. It includes a flap 33 having a pair of parallel beads 34, 35 with a groove 36 between them. A tongue 37 on the other fiap 38 locks into the groove 36, the enlarged, flared shape and the elasticity of the material helping obtain this result. Figs. 7, 8 and 9 show this structure in detail.
A similar result is obtained in the container 40, where a zipper 41 closes the opening 42 by leading the tongue 43 into the groove 44 between the two heads 45, 46.
Fig. 14 shows a package that is cylindrical, and has seamed ends 51 hermetically sealed.
Fig. 15 shows a cylindrical package 55 containing the same gel 11 as the other packages, with the ends 56 of the container gathered and held by fusing them together, by tying, or by a ring 57.
Figs. 1618 show an alternative method of obtaining a slab-like package, similar generally to the package 20. A flat sheet 60 of flexible wrapping material (e. g. wax paper or polyethylene or rubber) is placed on a fiat surface, and a slab of gel 61 is placed thereon, the slab being spaced in from the edges and from the midpoint of the sheet 60. The slab 61 may have been cut or sliced from a large bulk of gel or may be formed then. Then the sheet 60 is folded over at 62 on top of the gel 61 and pressed down evenly. This sandwich 63 may then be used as a covered refrigerant, and is a very practical means of handling and applying the refrigerant in many commercial applications, especially in sizes of about 12" x 16" x 1. However, a longer lasting gel, and one which may contain more water per solids (making it cheaper and also a better refrigerant), can be made by sealing the edges, as with freezer tape 64, or by welding the plastic.
Figs. 19 to 21 show another way to utilize the same basic idea in a cylindrical package. Here a flat sheet 70 has a slab 71 of gel laid thereon. Then the sheet 70 and gel 71 are rolled up together like a jelly roll to form the cylinder 72 of Fig. 20. This cylindrical refrigerant will hold its shape very well. For greater permanence, the ends 73 may be gathered together and tied with :a string 74 or welded or otherwise fastened together.
To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.
1. A refrigerant holdever package for use as a semipermanent refrigerant which can be repeatedly frozen and thawed, consisting essentially of a gel chosen from the class consisting of the gels of starch, bentonite, and cellulose gum, said gel including water as the main ingredient, said gel being encased in a sealed waterproof container, said gel serving to seal punctures made in said container.
2. A process for making a shaped refrigerant article, comprising the steps of filling a container partially full of water and a substance that reacts with said water to form a generally water-tight gel, sealing the resulting gel in said container, exerting pressure on the container to shape said gel, and puncturing the container while it is under pressure to eliminate entrapped air, said gel operating to seal the puncture.
3. A method for making a shaped refrigerant article, comprising the steps of filling a container with a hot gel which on cooling will be substantially water-tight, sealing said container shut, applying pressure to shape the gel in the container and drive contained air to a predetermined locus, puncturing said container to let said contained air out, and cooling said gel in its container.
4. A method for making a shaped, non-leaking, refrigerant article, comprising the steps of introducing simultaneously into a container water and a water-gelling substance chosen from the group consisting of starch, bentonite, and cellulose gum, mixing them to form a gel, and shaping said gel under pressure in said container.
5. A refrigerant holdover package for use as a semipermanent refrigerant which can be repeatedly frozen and thawed, consisting essentially of a gel composed essentially of starch, borax, and water in proportions of between 300 and 2,000 parts of water and between 13 and parts of borax per 100 parts of starch, said gel being encased in a sealed Water-proof container, said gel serving to seal punctures made in said container.
6. A refrigerant holdover package for use as a semipermanent refrigerant which can be repeatedly frozen and thawed, consisting essentially of a gel composed essentially of starch, water, borax, and paraformaldehyde, in the approximate proportions of between 300 and 2,000 parts of water, between 3 and 100 parts of borax, and between /2 and 100 parts of paraformaldehyde, per 100 parts of starch, said gel being encased in a sealed waterproof container, said gel serving to seal punctures made in said container.
7. A process for making a shaped refrigerant article comprising the steps of filling a flexible water-proof container with gelling mixture of water, borax, and starch in the proportions of between about 300 and 2,000 parts of water and between about 13 and 100 parts of borax per 100 parts of starch, sealing the resulting gel in said container, exerting pressure on the container to shape said gel, and puncturing the container while it is under pressure to eliminate entrapped air, said gel acting to seal the puncture.
8. A process for making a shaped refrigerant article comprising the steps of filling a flexible water-proof container with a gelling mixture of water, borax, paraformaldehyde, and starch in the approximate proportions of between 300 and 2,000 parts of water, between 3 and 100 parts of borax, and between fa and 100 parts of paraformaldehyde, per 100 parts of starch, sealing said container shut, applying pressure to shape the gel in the container and drive the contained air to a predetermined locus, puncturing said container to let said contained air out, the gel sealing the puncture, and cooling the gel in said container.
9. The refrigerant holdover package as set forth in claim 1 wherein said package is of generally cylindrical sausage configuration.
10. The refrigerant holdover package as set forth in claim 1 wherein said package is a roll of frozen gel and the container is sheet material, rolled like a jelly roll.
References Cited in the file of this patent UNITED STATES PATENTS 1,889,882 Woods Dec. 6. 1932 1,988,058 Traller Jan. 15, 1935 2,154,933 Hadsell Apr. 18, 1939 2,210,946 Moore Aug. 13, 1940 2,490,047 Gilchrist et al. Dec. 6, 1949 2,515,582 Beckwith et a1. July 18, 1950 2,574,763 Sears Nov. 13, 1951