GB2248675A

GB2248675A - A heat exchanger for cooling bodies by evaporation

Info

Publication number: GB2248675A
Application number: GB9021414A
Authority: GB
Inventors: John Patrick Sale Nolan
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-10-02
Filing date: 1990-10-02
Publication date: 1992-04-15
Anticipated expiration: 2010-10-02
Also published as: GB2248675B; GB9021414D0

Abstract

A heat exchanger for cooling a body (5) by evaporation, comprises a pad (4) which can absorb an evaporable liquid (2), and a wick (3) for supplying liquid from a container (1) which stores the liquid. The rate of supply of liquid to the pad may be controlled. As shown, a device (6) enables the wick (3) to make or break contact with the pad (4). The heat exchanger may be used for cooling the bodies of warm-blooded animals, thereby reducing sweating. Preferably, the pad (4) will be in good bodily contact, as close to the sources of body heat generation as possible. in another embodiment, the wick (3) is replaced by a tube, liquid being squeezed along the tube to the pad (4) when required. Alternatively, a control valve in the tube may be provided dependent on temperature, time or the evaporation rate of the liquid. <IMAGE>

Description

Title :- HEAT EXCHANGER This invention relates to a heat exchanger for transferring heat by evaporation. The heat exchanger may be used, for example, for the cooling of bodies generally and, more particularly, can be embodied in order to obtain a number of advantages by its use to cool the bodies of animals by the evaporation of water, or other suitable liquid, reducing the need for such bodies to keep cool by sweating, with the accompanying disadvantages.

There are several problems associated with natural sweating when the bodies of warm-blooded animals become overheated. The production of sweat removes essential chemicals and moisture that have to be replaced. In the case of humans in particular, the moisture must be replaced by water fit to drink. There can therefore be not only a health/nutrition problem, but also a problem of drinking water supply. Then excessive sweating requires further water for washing. Under some conditions, excessive sweating can produce excessive cooling of the body, particularly when the body becomes inactive suddenly after a period of activity.

The cooling of animal bodies by sweating may therefore be described in terms of a number of variables that include the difference in temperature between ambient and normal body temperature, ambient relative humidity, the rate at which the body is doing work, the rate of loss of body water and the rate of loss of vital chemicals.

The problem facing the present invention, hereinafter called "the invention", is to create an improvement or improvements by reducing some of the problems associated with normal sweating, eg the loss of body water and other chemicals, the need for replacement chemicals and/or potable water, the need for water for washing and risk of overcooling. A further aim is to improve on simpler methods of applying liquids externally for cooling purposes.

According to one aspect of the invention there is provided a device for cooling bodies, comprising an element, hereina-fter referred to simply as "active element", which can absorb an evaporable liquid and from which said liquid can evaporate, means for supplying said active element with said evaporable liquid and storage means for storing a quantity of said evaporable liquid. The invention may include a control means which can control the rate of supply of said evaporable liquid from said storage means to said active element according to some measurable quantity such as body temperature or the rate of evaporation of said evaporable liquid.

In all the embodiments now to be described, the said active element is in the form of a pad, preferably flexible, and the bodies to be cooled are human.

Embodiments of the invention will now be described, by way of example, with reference to the following schematic drawings, in which: Figure 1 is a side elevation of a cooling device comprising a container for evaporable liquid, a supply and control means provided by a wick, and an active element.

Figure 2 is a side elevation of a cooling device comprising a non-rigid container for evaporable liquid, a supply means provided by a tube, and an active element.

Figure 3 is a side elevation of a cooling device comprising a container for evaporable liquid, a supply means provided by a tube, an unspecified control means, and an active element.

Referring to Figure 1, an embodiment is shown that features a container, 1, enclosing an evaporable liquid, 2. A wick, 3, dips into 2. The wick, 3, may be brought into contact with an absorbent pad, 4, which is preferably in close contact with a suitable part, 5, of a body to be cooled. A device, 6, enables the wick, 3, to make or break contact with the pad, 4. Preferably, 1, has a small breathing hole or inlet valve 7, of known design.

Feature 7 is designed to prevent a reduction in pressure in container, 1, which might impede the flow of liquid, 2, this liquid being preferably water. Features 3 and 6 provide a simple supply and control for the liquid flow.

Should the wearer start to overheat, he/she can pull, for example, a cord, not shown, that activates 6. In one form, 6, might be a flat plate of some suitable material, such as stainless steel or plastic, which slides between the end of the said wick and the said pad. Alternatively, it could be arranged for, 6, to retract the wick, 3, into the container, 1, when cooling is not required. In many embodiments of, 6, it could be arranged for, 6, to have two positions "ON" and "OFF", each pull of the cord toggles between the two. This embodiment may be attached to said body to be cooled in by any known means, not shown. This embodiment has the advantage of being basically "one-piece", but it has the disadvantage that the container and pad must be in the same place. This may limit the size of the container. The embodiment of Figure 2 seeks to overcome this problem.

Referring to Figure 2, an embodiment is shown that features a non-rigid container, 1, enclosing an evaporable liquid, 2. A tube, 3, passes into the bottom of, 1, via an air tight seal. The tube, 3, passes up to an absorbent pad, 4, which is positioned as for the embodiment of Figure 1. Should the wearer start to overheat, he/she can squeeze the container, 1. This will force the liquid, 2, up the tube, 3, and onto the pad, 4. For reasons already given for the embodiment of Figure 1, it is probably preferable to position the pad, 4, as for the embodiment of Figure 1. This embodiment, shown in Figure 2, has the advantage of simplicity, no additional liquid control is required. Flow control is crude but is usually, in the case of a human being, under the direct control of the wearer. Usually, the wearer is in the best position to decide whether he/she is overheating.The container, 1, may have its own attachment means such as 'a belt or harness, 6.

Referring to Figure 3, an embodiment is shown that is similar to that of Figure 2. It features a rigid or nonrigid container, 1, enclosing an evaporable liquid, 2. A tube 3, passes into the bottom of, 1, via an air tight seal. The tube 3, passes up to an absorbent pad, 4, the positioning of which has already been described in the earlier embodiments. The container, 1, may be fixed to a belt or harness, 6. In normal use the container, 1, is pressurised by any known means, 7. Should the wearer start to overheat, a control system 8, located in, 3, and responding to a suitable physical quantity, will allow liquid to pass to the pad, 4. The control system, 8, can operate by any known means. Suitable physical quantities may include the temperature difference between the required body temperature and the actual body temperature and suitable time functions of said temperature difference, or the rate of evaporation of said evaporable liquid from pad, 4, and suitable time functions of said rate of evaporation. The control system will allow the said pressure to force the liquid, 2, up the tube, 3, and on to the pad, 4. This embodiment has the advantage of automatic control of liquid flow, and is not dependent upon a conscious action of the wearer of the device. This could be of particular advantage where the wearer of the invention is disabled in some way, or asleep.

In all these embodiments, it is preferable that pad, 4, is as close to the sources of body heat generation as possible, eg large muscles. But blood circulation can probably be relied upon to transfer heat from hotter to cooler parts. Thus the whole body may be cooled by cooling only parts of it by this invention. In the case of cooling humans, the pad may either be formed by part of the clothing, or it may be separate from the clothing, but attached by such means as "Velcro" (trade name) or pins.

More generally, where the pad is not part of the clothing, or clothing is absent, it could be attached to a harness.

In the case of human beings, and for all the embodiments herein described with reference to the figures, it is probably preferable to position the pad, 4, on the upper back as this part of the body may be more convenient of access and less susceptible to overcooling than other parts.

All parts of this invention, in any of its embodiments, must be attached securely by known means.

Claims

What I claim is:

1. A device for cooling bodies, comprising an active element which can absorb an evaporable liquid and from which said liquid can evaporate, means for supplying said active element with said evaporable liquid and a storage means for storing a quantity of evaporable liquid.

2. As Claim 1, in which there is provided said evaporable liquid.

3. As Claims 1 or 2, in which said supply means and said storage means are one unit.

4. As Claims 1 or 2, in which said supply means includes a tube.

5. As any of previous claims in which said storage means is a container, substantially closed.

6. As any of previous claims in which said supply means includes a wick.

7. As any of previous claims including a control means which can control the rate of supply of said evaporable liquid.

8. As Claims 6 or 7, in which said wick provides part of the said control means.

9. As Claims 6 or 7, in which said wick provides the said control means.

10. As Claims 7 or 8, in which said control means responds to one or more suitable physical quantities.

11. As Claim 10, in which said physical quantity or quantities include the temperature difference between the required body temperature and the actual body temperature and one or more time functions of said temperature difference.

12. As Claim 11, in which said physical quantity or quantities include the rate of evaporation of said evaporable liquid one or more time functions of said rate of evaporation.

13. As any of previous claims in which said evaporable liquid is substantially water.

14. As any of previous claims in which are provided attachment means for said active element.

15. As Claim 14, in which said attachment means for said active element are separable strips such as "Velcro" (trade name) one part attached to clothing on said body to be cooled and the other part attached to said active element.

16. As Claim 13 in which said attachment means for said active element are separable strips one part attached to a harness on said body to be cooled and the other part attached to said active element.

17. As any of Claims 1 to 14, in which said active element is a part of said clothing.

18. As any of previous claims in which said active element is in close proximity to a part of said body to be cooled.

19. As any of previous claims in which are provided attachment means for said storage means.

20. A cooling device substantially as herein described with reference to Figure 1 of the accompanying drawings.

21. A cooling device substantially as herein described with reference to Figure 2 of the accompanying drawings.

22. A cooling device substantially as herein described with reference to Figure 3 of the accompanying drawings.

23. A cooling device substantially as herein described.