US2467792A

US2467792A - Self-cooling water bag

Info

Publication number: US2467792A
Application number: US589932A
Authority: US
Inventors: Fred H Wenzel; Herman F Wenzel
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-04-23
Filing date: 1945-04-23
Publication date: 1949-04-19
Anticipated expiration: 1966-04-19

Description

April 19, 1949. F. H. wENzEL ETAI..

SELF- COOLING WATER BAG Filed April 23, 1945 LL 5 i n @2N M NE e TW. N.F T EHN Q. H /voa F Patented Apr. 19, 1949 SELF- COOLING WATER BAG Fred H. Wenzel, St. Louis, and Herman F. Wenzel, Fenton, Mo.

Application April 23, 1945, Serial No. 589,932

3 Claims. 1

The present invention relates to a4 water bag, and more particularly a water bag made of fabric material designed to have a controlled oozing or exudation of water therefrom, in restricted quantities, designed-to provide evaporation that will cool the contents of the bag.

This application is a continuation in part of application Serial No. 412,158, filed September 24, 1941, now abandoned, for Water bag and method of making same, by the applicants hereof.

Heretofore, water bags adapted to keep water cool through an evaporation process have been made of flax imported from Europe. The applicants have developed a water bag of treated cloth and a novel method of preparing the cloth to replace the flax water bags.

Therefore, it is an object of the present invention to provide a novel method of treating nonilax cloth to render it suitable for use in making water bags. y

Another object is to provide a novel method of treating non-flax cloth to produce a cloth which is adapted to permit seepage, for evaporation purposes, for maintaining water in a bag constructed of the material thereof at a cool temperature.

Another object is to provide a novel water bag of treated non-flax cloth which permits seepage for evaporation purposes at warm temperatures, above that of the water, to maintain the water therein at a cool temperature.

Another object is to provide a novel method of treating cotton cloth to render it suitable for water bag construction.

Specifically, an object of the invention is to provide a water bag made of readily available and relatively inexpensive fabric, such as cotton material, treated so as to obtain the characteristics exhibited by flax when used for this purpose. Particularly, it is an object to provide a water bag, made ofinitially porous material, with an impregnator, to restrict the exudation of water therethrough to amounts giving a lm of moisture on the outer surface, particularly where the film supplies water for evaporation, without excessive dripping, that reduces the temperature of Athe water in the bag toward wet bulb temperature.

It has heretofore been known that flax has the peculiar property, when made into a water bag, of providing a restricted seepage of water through the bag to the outer surface thereof, that supplies a. wetness to the fibers, and, at atmospheric conditions representing a mean of those in which it is designed for use, a film of water 0n said outer surface.

Such flax bags have the foregoing property only after they have been water soaked for long periods, such as 24 hours. Also, they are subject to becoming musty, giving a flavor and aroma to the .water that is undesirable. Flax is not a readily available material, and is relatively expensive, so that its use is further restricted.

Efforts have been made for many years to use domestic and inexpensive cloths for purposes such as water bags. The efforts have been unsuccessful up until the present invention becauseof the inability to control the seepage of Water through the material. It has been found by the present applicants that cotton and like non-flax materials can be prepared with the addition of preparations that control the interstitial spaces, between the fibers and between the threads, in such wise as to get a regulatable exudation of moisture therethrough. l

Water bags must'have a seepage at least substantially within the range of possible evaporation from the outside surfaces of the bag. If more water than this seeps through, it will not evaporate, but will drip from the bag as wastage, and also as a possible nuisance to the user. If the bag material, however, is so tight that no seepage at all occurs, then no cooling can take place.

As noted, the purpose of the present invention is to impregnate non-flax material, and particularly cotton, such as cotton duck or twill, with a material that tends to fill the interstitial spaces of the fibers, to delimit the passage of water through the ber to controlled quantities substantially within the range of possible evaporation from the outer surfaces of the bag.

In the drawing:

Fig. 1 is a side elevation of a water bag fof the' present invention; Y

Fig. 2 is a somewhat schematically shown greatly magnified portion of the fabric of the bag of Fig. 1.

The bag 5 is shown as having a top closure and handle combination shown at B, and a conventional spout with closure; shown at 1. Neither the handle 6 nor the spout 1 is part ofthe invention claimed herein.

The bag 5 is made of impregnated fabric, which consists ofa fabric containing the solid residue of a dispersion (as will appear) resulting from the application of the dispersion tothe cloth and the elimination of the liquid substance therefrom.

One particular method of accomplishing this is by impregnating cotton duck with paraffin derived from a water emulsion of parailin. The emulsion may be prepared from paraffin, water.

and one of the familiar water soluble emulsiflers. A wax proportion of 12%% has been found satisfactory for many atmospheric circumstances.

A cold bath of this parailin emulsion may be used, as the impregnation takes place as well from a bath that is cold as from one that is warm or hot. The emulsion may be placed in a container wherein there are cloth rollers, and the cotton cloth run through the emulsion over the rollers. Thereafter it is hung up to enable the water to evaporate therefrom. When the water is evaporated, the impregnated material may be re-rolled for convenience in handling, and then cut and sewed into bag form, with proper outlet.

Fig. 2 illustrates, in somewhat schematic manner, a magnified section I of a bag impregnated with the residue of the paramn wax emulsion. Such residue leaves a multiplicity of minute particles that adhere to and among the fibers and threads of the fabric, and constrict the size of theinterstices therethrough, leaving only small interstices that transmit limited amounts of liquid through the fabric. A typical cotton duck for water bags is that having a weight of about 18 ounces per square yard, single-filled. A weight range of 14 to 24 ounces for the above emulsion is satisfactory. Or a twill of 11.6 ounce weight is particularly desirable. The choice of the weave is determined by certain factors later to be described.

As suggested in the former application, the water emulsion of parailln is the most desirable preparation for the purpose at hand. Solvents in place of emulsifying agents have been used, of which gasoline maybe mentioned as typical. Thesey solvents, however, almost invariably impart a taste and a residual aroma to the material, and hence are undesirable where such taste and aroma are unacceptable. Also a water emulsion is much cheaper to use than a solution containing an expensive solvent, and the wax-water emulsion is easy to handle.

Certain plastic materials, dissolved in conventional solvents and impregnated into the cloth in a manner similar to the wax solutions or by painting onto the surface, with provision for the evaporation of the solvent, may also be used. However, the results have not proved as uniform as those obtained with the parafiin-water emulsion.

It will be noticed that the impregnator materials recited are amorphous, water insoluble, and more or less pliable at ordinary atmospheric temperatures. As a result, they tend to adhere to the fibres and to be retained by them, during use of the bag, in contrast to hard, crystalline particles.

It has been found that, ideally, the amount of water seeping through a water bag should be just enough to provide the evaporation necessary to preserve the wet bulb temperature of the water within the bag. For practical reasons, it is, of course, virtually impossible to provide the precise amount for obtaining Wet bulb temperature. Either some dripping occurs, or less exudation than that required for maintaining wet bulb temperature is provided. This is particularly true as variations in the amount of seepage through any treated material do not vary exactly as wet bulb temperature varies. Hence, the bag that is usable for certain dry and wet bulb temperature conditions and evaporation rates might not be proper for others. A bag to be used on a desert, where the relative humidity is very low and the dry bulb temperature very high, must have a very libture.

eral seepage in order to provide the volume of water to evaporate that will keep the temperature of the water approximating wet bulb condltions. If such a bag were used under conditions of high humidity, its seepage would be so great, and so much in excess of evaporation rates, as to result in undesirable dripping from it.

However, any reasonable amount of seepage and evaporation will produce a sensible lowering of temperature within the bag over that at the exterior. For instance, a certain bag, operating under dry bulb temperature of approximately 103 F. and relative humidity of approximately 29.8, and losing 16.5% of its water within a period of 8 hours, maintained a water temperature of 90 F. or below, the temperature increasing from approximately 80 to the 90 during the course oi' the last 7 hours. Another bag, operating under identical conditions but providing a water loss through seepage of 24.4% maintained the water within the bag at a temperature of approximately the wet bulb value of 78 F. at the end of 8 hours. the temperature rising from to 78 during the course of the last 7 hours.

Thus, the bag with the lower seepage did not4 keep the water vas cool as that with the higher percentage of water loss, but, nevertheless, did maintain the water more than 10 below outside temperature.

In another test, the bag in the foregoing example, having 16.5% water loss in 8 hours, was subjected to outside temperature conditions of 921/2" F. with a high relative humidity of 72%. After 9 hours, this bag showed a water temperature of approximately wet bulb value. Hence, the seepage permitted by this particular bag was substantially ideal for the particular wet bulb temperature conditions of the second test.

The result of the tests that have been made show that, for low humidity and high temperature conditions, the bag must be made to have a high seepage rate; whereas, for high humidity, the seepage rate will be lower because of the low er capacity of the atmosphere to take up mois- Obviously, if the moisture cannot be absorbed as evaporation, it will drip ot! and be obiectionable in the use of the bag.

The control of the water seepage is obtained by varying the size of the permitted interstices in the cloth of which the bag is composed. With a very tight weave of cotton cloth, such as the 18 ounce duck heretofore mentioned, for example, a 121/2% wax emulsion gives the aforementioned bag having the 16.5% water loss in 8 hours, at 103 F. dry bulb temperature and 29.8% relative humidity. A twill bag, however, immersed in the same emulsion, provides greater seepage of water. The twill bag, therefore, would be more acceptable in localities where there is a high evaporation of moisture; whereas the duck bag would be emlnently satisfactory in places of high humidity where the evaporation capacity is low.

For given zones or areas, ranges of conditions can be observed and made the basis for the manufacture of bags used therein. To illustrate, a desert style bag may be manufactured having a high rate of seepage for use in conditions of high temperature and low humidity. On the other hand, a bag may be made for use in such climates as certain parts of Florida where the humidity rate is very high, and, consequently, the evaporation rate very low, this bag having small inter-y stices and low seepage rate.

The seepage rate may be controlled to a large degree by adjusting the percentage of wax in the emulsion. It also may be controlled by varying the Weave of the cloth used, so that it becomes less'penetrable by water. Also, the diiferent types of ller material or impregnator vary the seepage rate.

In summary, it may be said that as an overall matter the seepage must be something from a visible seepage up to a condition just short of where excessive and undesirable dripping comes from the bag. An adequate bag may be obtained hy applying' a simple observation test, under the approximate mean conditions of use, to see Whether there is any evaporation at all, as a minimum limit, or whether there is excessive dripping as a maximum limit.

, A normally good bag, tested at mean atmospheric conditions of use, will show a thin iilm of water over its outer surface, preferably with no dry spots indicating areas of irregularl exudation, Without any more than a slight dripping. On the other hand, the most satisfactory bag would be determined mathematically for the conditions under-which it is to be used, and manufactured to give an amount of evaporation approximating that required for withdrawing the amount of heat to maintain wet bulb conditions of the water contained.

What is claimed is.

1. A self-cooling container for Water or other liquids comprising a liquid-holding bag at least one wall of which is made of fabric having small openings large enough to permit seepage therethrough but in uncontrolled quantity, means to control said seepage comprising an impregnator which consists of the solid residue resulting from the evaporation of a liquid dispersion of a substance that is amorphous, Water insoluble, relatively hard atI low temperatures, relatively soft at high temperatures, and increasing in softness as the temperature rises, the impregnator being distributed throughout the fabric of the .bag to constrict the size of said openings thereby to control the rate of seepage therethrough, the size of said openings being so controlled by the impregnator as to transmit water through the fabric to form a film on the exterior of the bag and to keep the water transmission to amounts substantially within the evaporation capacity of the atmosphere as the condition ofthe atmosphere changes, whereby the evaporation of the water from. the film will draw heat from the liquid within the bag and restrict rise in temperature of said liquid. l

2. A self-cooling container for water or other liquids comprising a liquid-holding bag at least one wall of which is made of fabric having small openings large enough to permit seepage therethrough but-in uncontrolled quantity, means to control said seepage comprising an impregnator which consists of the solid residue of a dilute emulsion of an amorphous, Water insoluble substance, said substance being relatively hard at low temperatures, relatively soft at high temperatures, and which increases in softness as the temperature rises, the impregnator being distributed throughout the fabric of the bag to constrict the size of said openings thereby to control the rate of seepage therethrough, the size of said openings being so controlled by the impregnator as to transmit Water through the fabric to form a film on the exterior of the bag and to keep the water transmission to amounts substantially within the evaporation capacity of the atmosphere as the condition of the atmosphere changes, whereby the evaporation of the water from the ilm Will draw heat from the liquid within the bagr and restrict rise in temperature of said liquid. l

3. A self-cooling container for water or other liquids comprising a liquid-holding bag at least one wall of which is made of fabric having small openings large enough to permit seepage there--v through but in uncontrolled quantity, means to control said seepage comprising an impregnator which consists of the solid residue of a dilute emulsion of a paran wax, the impregnator being distributed throughout the fabric of the bag to constrict the size of said openings thereby to control the rate of seepage therethrough, the ysize of said openings being so controlled by the impregnator as to transmit water through the fabric to form a film on the exterior of the bag and to keep the water transmission to amounts substantially within the evaporation capacity of the atmosphere as the condition of the atmosphere changes, whereby the evaporation of the water from the film will draw heat from the liquid within the bag and restrict rise in temperature of said liquid.

FRED H. WENZEL.

HERMAN F. WENZEL.

REFERENCES CITED lThe following references are of record in the le of this patent:

UNITED STATES PATENTS Number