GB2243988A

GB2243988A - Heat transfer garment

Info

Publication number: GB2243988A
Application number: GB9109000A
Authority: GB
Inventors: Paul A Browne; Kirk A Dobbs
Original assignee: Atomic Energy of Canada Ltd AECL
Current assignee: Atomic Energy of Canada Ltd AECL
Priority date: 1990-04-27
Filing date: 1991-04-26
Publication date: 1991-11-20
Anticipated expiration: 2011-04-26
Also published as: GB2243988B; CA2015621A1; FR2661319B1; FR2661319A1; CA2015621C; IT1247433B; ITMI911160A0; ITMI911160A1; DE4113679C2; GB9109000D0; DE4113679A1

Abstract

A heat transfer garment, for modulating the heat flow to or from the body of the user, comprises an assembly of fabric constructed to conform substantially to the contours of a body portion over which it is to be used, a plurality of lengths of flexible tubes 28 secured to one sunface of the fabric so as to extend along the length of the fabric, the lengths of tube being substantially uniformly spaced apart transversely of the fabric and each length being substantially sinusoidal in shape along a major portion of its length, and adjacent lengths being substantially in-phase with one another, means for supplying heat transfer liquid to one end of each the tube, and means for receiving heat transfer liquid discharged from the opposite end of the tubes. The tubes are preferably attached to the fabric by means of zig-zag stitching as shown in Fig. 5. <IMAGE>

Description

... -. ' - HEAT TRANSFER GARMENT -, T_--; - The present invention relates

to a heat exchanging garment useful for heating or cooling the human body in circumstances where the body's natural mechanisms of temperature regulation are impeded or overwhelmed. Heat transfer garments may be used for heating all parts of the body in environments where passively insulating clothing provides insufficient protection, for example in cold water diving, or in outdoor activities in winter conditions. Such garments may also be used to provide cooling for persons wearing clothing which impedes cooling by the evaporation of perspiration, for example persons using vapourimpermeable suits to protect them against toxic chemicals.

BACKGROUND OF THE INVENTION

In the past, several garments to provide cooling have been developed. These have included systems which pass air over the body, garments which incorporate ice or solid carbon dioxide in pockets, and garments which cool by circulating a chilled liquid through passages in the garment. United States Patent No. 3,430,688 describes a circulating liquid garment to be used in cooling the user. Circulating liquid garments have also been used to heat the body. United States Patent No. 3,744,053 describes a circulating liquid garment to be used for warming the user.

JENNINGS United States Patent No. 3,289,748 provides a heat transfer garment having heat transfer tubes which are distributed in a serpentine or meandering pattern so that the distribution of the tubing over the body is in approximate proportion to the local body mass to thereby provide heat removal capacity commensurate with metabolic heat generation capability. The spacing between the tubes and the shapes of the tubes along their lengths vary to provide the desired heat removal capability. A drawback to this arrangement is that the tubes are almost straight in regions, such as the waist, where maximum curvature would be desirable to permit the user to bend over without discomfort. Furthermore, the arrangement is not readily susceptible to mass production because of the different shapes of the various tubes required. Thus, the tubes must be positioned and shaped by hand and head in position on a fishnet-like cloth by individual, hand applied tacks.

BURTON United States Patent No. 3,425,486 illustrates a heat transfer garment having heat transfer tubes which are also distributed in a serpentine or meandering pattern similar to the JENNINGS patent. However, BURTON places little importance on the spacing and the shape of the tubes, but states that the tubes should avoid regions, such as at the elbows and behind the knees, where there is likely to be substantial bending. The essence of the BURTON patent is to provide tube locating means in the form of tunnels so that as the garment body stretches with movement of the wearer, the tubes will be able to slide and or twist within the tunnels so as to, in turn, reduce any restriction of movement. Like JENNINGS, the spacing between the tubes and the shapes of the tubes along their lengths vary to provide the desired heat removal capability. Thus, the BURTON arrangement suffers from the same disadvantages as the JENNINGS arrangement but includes additional complexity in terms of the cost and attachment of the tube locating tunnels to the garment.

Although prior designs of liquid circulating heat transfer garments have been shown capable of transferring heat at significant rates, these prior designs have proven to be uncomfortable to wear, either because such prior garments have covered too small a portion of the body's area for the heat transferred, or because of excessive bulk and restriction of the user's movements. Prior designs of liquid circulating heat transfer garments have also been subject to flow blockages due to pinching of the liquid passages, causing unreliable operation.

Prior designs of such garments have also been costly to manufacture.

SUMMARY OF THE INVENTION

The present invention seeks to provide a heat transfer garment which provides effective heating or cooling over sufficient body area to prevent thermal discomfort to the user, which does not unduly restrict movement of the user and is thus more comfortable than prior designs, which is not prone to flow blockage or leakage upon flexure of the body and thus operates reliably, and which may be manufactured at a reasonable cost, thus allowing its use in more applications.

This can be achieved by providing a plurality of lengths of flexible, heat transfer tubes which extend longitudinally of the garment or portion thereof, with the lengths of tube being substantially equally spaced apart and being secured to the garment so as to form a generally sinusoidal shape along a major portion of the length of the tubes and with adjacent sections of tubes being substantially in-phase with one another.

Thus, the present invention is generally defined as a heat transfer garment for modulating the heat flow to or from the body of the user, the garment comprising an assembly of fabric constructed to conform substantially to the contours of a body portion over which it is to be used, a plurality of lengths of flexible tubes secured to one surface of the fabric so as to extend along the length of the fabric, the lengths of tube being substantially uniformly spaced apart transversely of the fabric and each length being substantially sinusoidal in shape along a major portion of its length, and adjacent lengths being substantially in phase with one another, means for supplying heat transfer liquid to one end of each the tube, and means for receiving heat transfer liquid discharged from the opposite end of the tubes.

In this manner, heat is distributed substantially uniformly over the portion of the body covered by the garment. The sinusoidal shape readily accommodates bending without discomfort to the user so that it is not necessary to avoid the provision of tubes at bend points or axes while also avoiding of sharp bends in the tubes which could block flow. Further, since the tubes are arranged in a uniform pattern on the garment, the garments may be relatively easily mass produced.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings wherein:

FIGURE 1 is a front view of heat transfer garment in the form of a shirt according to a preferred embodiment of the present invention; FIGURE 2 is a back view of the heat transfer garments in the form of a pair of trousers according to a preferred embodiment of the present invention; FIGURE 3 is an enlarged fragmentary view showing a portion of the garment in detail; FIGURE 4 is a detail view showing a portion of the garment where two tubes are gathered to a single tube; FIGURE 5 is a detail view showing a method of tube attachment to the supporting cloth; and FIGURE 6 is a graph illustrating measured heat transfer performance of a medium sized sleeveless shirt constructed in accordance with the present invention.

DESCRIPTION OF PREFERRED EMBODIMENT 20 FIGURES 1 and 2 illustrate two articles of heat transfer clothing including a long-sleeved shirt 10 and trousers 12. Although these two are shown, it is understood that any other type of heat transfer clothing may be constructed according to this invention, such as coveralls, gloves, mitts, socks, shoes or boots, vests, hoods or caps. Each section of both articles includes a plurality of lengths of heat transfer tubes 14 which extend longitudinally of the section of the garment. In the case of the shirt 10, 11sectiod means the torso portion and the sleeves. In the case of the trousers 12, "section" means the leg portions optionally extending up into the lower torso portion. The lengths are spaced apart substantially equally in a 30 transverse or circumferential direction and each length is secured to the garment so as to form a substantially sinusoidal shape with adjacent lengths being %n-phase" with one another. The axes of the sinusoidal shapes may diverge of

1 converge slightly in the sleeves and legs of the garment without departing from the spirit of the invention. The term "in-phase" means that the centres of curvature of the curved portions of the lengths of tube are circumferentially aligned, as best shown in FIGURE 3. It will be seen that this arrangement will provide uniform stresses in both longitudinal and transverse directions and the weight of the garment will be substantially uniform in all regions. This will be reflected as more comfortable to the user. Further, when the garment is folded as a result of bending of the body, all of the tubes will bend at essentially the same point along their respective lengths and this again will be more comfortable to the user. Still further, the heat transfer to or from the body will be uniform and more comfortable as compared to tubes lengths concentrated in predetermined regions as suggested by the prior art.

In the illustrated embodiment, a single tube provides several lengths in which a portion of the tube extends in one longitudinal direction, turns back on itself and then extends in the opposite direction and so on. It will be understood that the heat transfer tubes may be connected in parallel to a source of suitable heat transfer fluid so as to provide more uniform heat transfer distribution to the skin of the user. The present invention contemplates all such obvious ways of arranging the tubes.

In use, heat exchanging liquid is injected through an inlet tether tube 16 to liquid inlet tubes 20 and 22 in the shirt 10 and trousers 12, respectively. In the shirt, the heat exchanging liquid passes from inlet tube 20 through tee- like fittings 24, illustrated in FIGURE 4, and into an inlet manifold tube 26 which feeds a plurality of individual tubes 28. The heat exchanging liquid which passes through tubes 28 exchange heat with the skin of the user, thus cooling or heating the user's trunk and arms. Tubes 28 discharge into a discharge manifold tube 30, through tee-like fittings 24, which in turn discharges into outlet tube 12 and finally to an outlet tether tube 32. It will be noted that manifolds 26 and 30 are in the form of a collar of the shirt. As shown in FIGURE 1, each individual tube 28 provides four lengths of tube extending along the length of the garment. In a similar fashion, the trousers are formed with inlet and outlet tubes respectively connected to inlet and outlet manifold tubes interconnected by parallel individual beat exchange tubes.

Outlet tether tube 32 is connected to a heat exchanger 40 and pump 42, as shown in FIGURE 1, before returning to the heat transfer garment through inlet tether tube 16. When used in cooling, the heat exchanger may be an ice bath, a device cooled with solid carbon dioxide, or a mechanical or thermoelectric refrigeration unit. When used in heating, the heat exchanger may be an electric or a fuel burning heater.

A preferred method of affixing the heat transfer tubes to the supporting cloth 50 is shown in FIGURE 5. The method employs zig-zag stitching using a first thread 52 on the tube side of the cloth which interlocks with a second thread 54 on the opposite side of the cloth so as to hold the tube in place along its length. This method of stitching may be done by machine, thus eliminating the manual stitching used in previous garments and reducing the cost of the garment.

An advantage of attaching the tube to the cloth along its length is that the tube is less susceptible to kinking when supported continuously by the cloth. Other methods of affixing the tubing to the supporting cloth may also be employed. Such alternate methods include glues, and solvent welding or thermal welding for cloth of certain synthetic materials, such as polypropylene.

Garments constructed according to the invention may be worn with the tubes directly against the skin, or, for more comfort, with the tubes disposed outwardly so that the tubes are separated from the skin by the supporting cloth. Alternately, light undergarments may also be worn under the heat transfer garments. A second layer of cloth may also be incorporated into the heat transfer garment so that the heat transfer tubes are covered on both sides. It has been found that more heat is transferred when the tubes are placed directly on Lhe skin, than when a layer of cloth separates the tubes from the skin. Heat transfer is also aided if the tubes are urged gently against the skin in a resilient manner.

The in-phase sinusoidal paths taken by the heat transfer tubes, as illustrated in FIGURE 3, is important in effecting close contact between the skin and heat transfer tubes continuously along the length of the tubes. The support cloth is preferably a stretch knit material, cut and sewn to fit tightly to the user and placed so that the direction of greatest stretch of the cloth is around the circumference of the body. Such stretch knit materials will shrink in the axial direction, as indicated by the arrow A, when stretched in the circumferential direction, as indicated by the arrow B. The heat transfer tubing will not easily be extended or compressed along its own axis. Accordingly, an important advantage of the sinusoidal shape of the heat transfer tubes is to allow the tube and cloth assembly to stretch circumferentially while maintaining close contact with the body as it moves. The sinusoidal pattern permits the tube and cloth assembly to shrink in the axial direction as it stretches circumferentially without causing the tubing to buckle away from the body in a series of bumps.

A further advantage of the in-phase sinusoidal arrangement of tubes is that the spacing between adjacent tube paths does not vary greatly along the length of the tube. This factor maximises the effectiveness of the tube used in transferring heat. It has been have found that in cooling use, the temperature of the skin is coldest directly under the heat transfer tube and is warmest at points most distant from the tubes. Conversely, in heating, the skin temperature is highest directly unde r the tube and lowest at points most distant from the tubes. The ability of the body to transfer heat to or from the tube is limited by the thermal conductivity of the skin and flesh and by the blood supply in the affected area. Because of this, it is apparent that more heat will be exchanged with a given length of tubing, if that tubing is located in a region little affected by adjacent tubes. The in-phase sinusoidal tube pattern used by heat transfer garments of this invention thus maximises heat transfer per unit length of tubing, while providing a garment which remains close to the body in a comfortable manner. It has also been found that the approximate spacing between adjacent sinusoidal tube paths may be varied throughout the garment to adjust the effectiveness of the garment in transferring heat to suit the circumstances, or to suit that portion of the body covered.

FIGURE 6 shows the measured heat transfer performance of one such garment, a medium-sized sleeveless shirt. In this garment, heat transfer tubes of flexible polyvinyl chloride were used, each tube having an outside diameter of 1/8 inch, an inside diameter of 1/16 inch and a length of approximately 16 feet. In FIGURE 6, the heat transfer can be seen to be negative, indicating body cooling, at average heat transfer liquid temperatures below 34'C, and positive, indicating body heating, at liquid temperatures above 349C.

While the forms of the apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OF PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A heat transfer garment for modulating the heat flow to or from the body of the user, said garment comprising:

an assembly of fabric constructed to conform substantially to the contours of a body portion over which it is to be used; a plurality of lengths of flexible tubes secured to one surface of said fabric so as to extend along the length of said fabric, said lengths of tube being substantially uniformly spaced apart transversely of said fabric and each length being substantially sinusoidal in shape along a major portion of its length, and adjacent lengths being substantially in- phase with one another; means for supplying heat transfer liquid to one end of each said tube; and means for receiving heat transfer liquid discharged from the opposite end of said tubes.

2. A heat transfer garment as defined in claim 1, said means for supplying heat transfer liquid to one end of each said tube comprising an inlet manifold tube connected to one end of each said flexible tubes by a T-shaped fitting.

3. A heat transfer garment as defined in claim 1, said means for supplying heat transfer liquid to the opposite end of each said tube comprising an inlet manifold tube connected to the opposite end of each said flexible tubes by a T-shaped fitting.

4. A heat transfer garment as defined in claim 1, said means for supplying heat transfer liquid to the opposite end of each said tube comprising an inlet manifold tube connected to the opposite end of each said flexible tubes by a T-shaped fitting.

5. A heat transfer garment as defined in claim 1, wherein said fabric is a stretch knit material.

6. A heat transfer garment as defined in claim 1, said flwdble tubes being secured to said supporting fabric with zig-zag stitching using a first thread on the tube side of the cloth which interlocks with a second thread on the opposite side of the cloth so as to hold the tube in place along its length.

7. A heat transfer garment as defined in claim 1, wherein the spacing between two said adjacent lengths varies gradually along the length of the adjacent sections and from adjacent section to adjacent section.

8. A heat transfer garment as defined in claim 1, wherein a second layer of fabric covers that side of the heat transfer tubing not in contact with the supporting fabric.

41 i

9. A heat transfer garment for modulating the heat flow to or from the body of the user, said garment comprising: an assembly of stretch knit material fabric constructed to conform substantially to the contours of a body portion over which it is to be used, said material being arranged so that the direction of greatest stretch of the material is around the circumference of said body portion; at least one flexible tube secured to one surface of said material by zig-zag stitching using a first thread on the tube side of the cloth which interlocks with a second thread on the opposite side of the cloth so as to hold the tube in place along its length, each said tube providing a plurality of lengths of tube extending along the length of said material substantially perpendicularly of the circumference of said body portion, said lengths of tube being substantially uniformly spaced apart about the circumference of said material, with each length being substantially sinusoidal in shape along a major portion of its length and with adjacent lengths being substantially in-phase with one another; a heat transfer liquid inlet manifold tube extending about the circumference of one end of said garment and connected to one end of each said flexible tube for supplying beat transfer liquid thereto; and a heat transfer liquid outlet manifold tube extending about the circumference of one end of said garment connected to opposite end of each said flexible tube for discharging heat transfer liquid therefrom.

Published 1991 at The Patent Office, Concept House. Cardiff Road. Newport, Gwent NP9 lRH. Further copies may be obtained from Sales Branch. Unit 6, Nine Mile Point, Cwnifelinfach. Cross Keys, Newport, NPI 7HZ. Printed by Multiplex techniques ltd, St Mary Cray. Kent.