Enhanced evaporative cooling system
Kind Code:

A blower operated cooling vest that uses the normal movement of the body to blot excess moisture from the body and evaporate it away from the body and thus shield it from the heat.

Horn, Stephen T. (White Stone, VA, US)
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Horn, Stephen T.
Phyllis C Horn joint Tenals in common
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Primary Examiner:
Attorney, Agent or Firm:
Stephen T. Horn (White Stone, VA, US)
I claim:

1. A method of reducing environmental heat being transferred to a person; said method comprising: a) providing a supporting structure, b) providing a blotting material, c) supporting a blotting material parallel to the torso and between said torso and said environmental heat, d) allowing said blotting material to absorb a portion of said environmental heat, e) allowing air to flow between said torso and said blotting material, f) providing moisture on said torso, g) providing a bending of said torso to allow a blotting of said moisture to transfer from said torso to said blotting material, h) allowing said moisture on blotting material to phase shift to a gas thus transferring heat and evaporating said moisture, i) allowing said air flow to remove said evaporated moisture and thus reduce the environmental heat being transferred to the body.

2. A method of cooling the body: said method comprising: a) providing a supporting structure, b) providing an absorbent material, c) providing air flow between said body and supported said absorbent material, said supported absorbent material supported parallel to said body and between said body and any heat source, d) providing moisture on said body, said body bending to provide contact between said body and said absorbent material, e) contacting between said body moisture and said absorbent material, f) transferring said moisture from said body to said absorbent material, f) evaporating said moisture from said body and said absorbent material with said air flow, thus removing heat from said body and said absorbent material, thus cooling said body.

3. A body cooling apparatus that includes a plenum created by supporting a flexible material off the body and a blower to force air between said body and said flexible material, wherein said flexible material is parallel to said body and interfering with said body absorbing environmental heat, wherein said body bends to blot sweat from said body to said flexible material where said blower blows air through said plenum created by said body and said flexible material whereby heat is transferred through evaporation from said body and said flexible material and said body is cooled.

4. claim 1 where said body is covered with clothing

5. claim 2 where said torso is covered with clothing

6. claim 1 where said air flow is provided by a blower

7. claim 2 where said air flow is provided by a blower

8. claim 1 where said auxiliary moisture is provided by a water source

9. claim 2 where said auxiliary moisture is provided by a water source









The present invention provides a means to use air by a fan or blower device to increase the evaporation of available moisture from an individual and thus cool them while they are wearing heavy protective equipment such as a military tactical vest. The present device through a blotting action removes moisture from individual and through wicking distributes this moisture throughout the fabric of the vest where it is then evaporated by the air flow and hence removes heat from being transferred from the outer protective vest to the individual.


U.S. Pat. No. 5,217,408 by Kaine issued on Jun. 8 1993 discusses a cooling vest that has a fan and a cowling to contain the pumped air. The present invention does not teach a blotting action to actively remove excess heat from the plenum surrounding the body. The present invention does not teach using an absorbent material to absorb and evaporate the excess moisture from sweat.

U.S. Pat. No. 6,874,332 by Forgach issued on Apr. 5, 2005 teaches a protective vest cooling system. Forgach teaches a protective vest for being worn over the body of the user and an elongated housing generally disposed inside the protective vest. The elongated housing has holes for the transfer of blown air. Forgach does not teach a blotting action or provide a method to increase the evaporative area beneath the protective vest.

U.S. Pat. No. 6,260,201 by Rankin issued on Jul. 17 of 2001 teaches a vest with a plurality of tubular members with each member having a peripheral wall having a plurality of openings therein. Rankin does not show how to increase the evaporative area of the vest nor does he describe how to increase the surface area of the body by blotting the excess moisture expressed by the body. Nor does he teach the method of reducing the effect of fatty oils floating on the perspiration on the body.


Cooling garments are widely used in industry and their utility is widely accepted. Evaporative cooling is the major method of cooling with the present invention. Particularly, the present invention is concerned with enhancing the evaporative cooling of the body by better using the water expressed in the sweat to cool the body.

Vests of this type typically use perforated tubing to force large amounts of air under an outer covering. The perforated tubing acts to conduct the air and is between the outer cover and the body. The present invention forces air under an absorbent material that is normal to the torso of the individual. The air pressure helps to keep the material from direct contact with the body. The plenum through which the air flows is between the body and the vest shell without tubing to obstruct flow or support the vest across the major portions of the back and front. A non air carrying structure both supports the vest absorbent material and the outer protective garment away from the body. In this case the outer protective garment is an OTV or outer tactical vest. This is a Interceptor bullet proof vest used by the army but could be used with any outer garment. By allowing the plenum which carries the air to be unobstructed in the middle of the torso by supporting the outer garment and the absorbent material at the shoulders away from the body but allows the absorbent material to remain flexible allows the wearer in normal walking and bending motion to blot excess moisture from the surface of the back and the front of the torso. The direct advantage of this is multifold. First, beaded sweat has far less surface area than skin that is just damp. Evaporation is proportional to surface area therefore the more surface area the more water or moisture from sweat will phase shift to a gas and allow it to be transferred away from the body by the air flow. Sweat forms smooth circular or rounded particles of moisture around and over the small cilia or very small hairs on the body when evaporation lags behind the body's expression of sweat. This effectively reduces the surface area for evaporative cooling. The same holds true for a saturated tee shirt over the body, the surface area for cooling is reduced. The surface area of the beaded sweat being less than the combined surface area of the skin surface and the pores and small hairs on the skin or the woven fibers of the shirt. This reduced surface area consequently reduces evaporation and reduces cooling. This is why people will typically wipe sweat from their forehead. It cools them better when the sweat is wiped away. Importantly the evaporative cooling potential of the water in the sweat is wasted as it is allowed to drip to the ground or in the case of the torso, to drip or run down the back of the person. When water from sweat can be transferred as a liquid from the body as by contact with another surface then effective cooling through the phase shift of that water is wasted. The second reason blotting is important is because the beaded sweat on the person typically has fats and oils that interferes with evaporative cooling and builds up on the skin as evaporation takes place. When the moisture is blotted the fats and oils in the sweat is interfered with and absorbed by the wicking material to then allow a greater portion of the water in the sweat to evaporate. The removal of this oil is important in enhancing the rate of evaporation from the body and hence the cooling of the body. Thirdly and possibly most importantly, the blotting of the sweat by the absorbent covering of the vest effectively doubles the evaporative surface usable to cool the body. The body often through a tee shirt evaporates water and cools but at the same time, it is absorbing heat being radiated by the outer protective vest. The vest being heated by the sun and other radiating surfaces in the environment as well as conduction from hot air. Thus in the present invention, the sun heats the outer protective vest which heats up and conducts the heat to the inside cooling vest. The cooling vest blots up excess moisture that ordinarily would be running down the torso of the soldier and then it is evaporated by the considerable amount of air being forced through the vest. This evaporation cools the body but also removes heat that would be radiated or conducted to the cooling vest and then to the body. Without the air plenum, being designed with minimum obstructions the heat from the environment would be directly conducted to the body. The space between the body and the vest around the torso means that heat from the environment is transferred primarily by radiation. This is reduced by the wet evaporative surface of the cooling vest. Here the moisture phase shifts to a gas on the surface with the transfer of energy to it. The net result of the blotting is the absorption of excess wasted sweat and the use of it to cool the body. The bending of the torso and the consequent blotting is mostly involuntary and part of normal movement.

When there is inadequate sweat as in very arid environments a minute amount of water from a water source can be inserted into the vest by a pump such as a squeeze bulb. A squeeze bulb pump with a canteen used for a water source was tested at Kansas State University, Institute for Environmental Research for use in injecting water under the vest to enhance the evaporative cooling of the vest and the blocking of environmental heat.

Another important aspect of the present invention is the plenum which conducts the air which removes the heat from around the body. The heat being transferred to a gas needs to be exhausted from the space between the body or torso and the vest. Once this air is saturated no further evaporative cooling is possible. However with very large volumes of even humid air evaporative cooling is effective. The plenum is designed to absolutely minimize obstructions to the flow of air. Rather than duct air through tubes as is normally done; the present invention eliminates tubing for the conduction of air and creates the plenum from the use of the torso as one surface and the vest as the other surface. The vest forming one large pipe in one sense and the torso being inserted into this pipe. This unobstructed air flow allows the transmission of large quantities of air with little back pressure and very importantly at very little energy costs from batteries. The inventor has a patent filed on the supporting structure for such air flow in a vest where the torso or body has a supporting structure to support the vest away from the body. This has also been shown to be effective at tests at Kansas State University where the air flow is large enough for tee shirts worn by the soldiers to be dry except where the supporting structure touches the torso and blocks evaporation from the tee shirt. The patent application Ser. No. is 11/361,866 filed by Stephen T. Horn on Feb. 24, 2006.

A vest such as this was tested at the Kansas State University Institute for Environmental Research in the spring of 2007. The measurement was at the top of the scale at 200 watts of heat transfer from the body. The tests were done using a sweating manikin. The inventor believes that significantly more heat transfer is easily achieved.

Further objects and advantages of my invention will become apparent from a consideration of the drawings and or ensuing description.


On sheet 1 FIG. 1, A is an outer covering or a protective vest. B is a supporting structure. C is a batten supporting structure. D is a blower which blows air under E between E and the torso. E is a blotting material.

On sheet 2 FIG. 1A is a cross section of the torso and of course and it need not be said any immediate covering such as a tee shirt. B is an outer covering or a protective vest. C is a supporting structure. D is also a supporting structure to maintain a space between A and E which is a blotting material. F is environmental heat from the sun and other sources. G through H is the air flow thru the plenum created by the torso A and the blotting material E.

On sheet 2 FIG. 2, A is the torso bending. B is the outer covering or a protective vest. C and D are supporting structures. E is a blotting material.


FIG. 1A sheet 1 is a protective vest such as the Interceptor vest. The protective vest is supported from the body by structures B and C in FIG. 1 sheet 1. FIG. 1E sheet 1 is an absorbent material such as cotton cloth however any material that will transfer moisture will work. Even plastic will blot water from a surface. FIG. 1E sheet 1 is separate from the Interceptor vest in this embodiment but it could be an integral part of the protective vest. D in FIG. 1 sheet 1 is a blower that blows air under the absorbent layer FIG. 1E sheet 1. The air from the blower will remove moisture through evaporation and cool the wearer. Humid conditions require more air but still cools the individual. The volume of the air necessary is proportional to the relative humidity until the air being pumped in is one hundred percent saturated.

FIG. 1 sheet 2 shows a cross section of the sectional side view of the torso with absorbent material and protective vest and shows the absorption of environmental heat by the outer protective vest. This method however will work on any part of the body. FIG. 1A sheet 2, is the torso itself, while FIG. 1B sheet 2 is the protective vest and FIG. 1C sheet 2 is the absorbent material. FIGS. 1D and E sheet 2 are supporting structures and in this case are battens that hold the protective vest from the body creating a plenum through which air is pumped by the blower. Air enters the created plenum at FIG. 1G sheet 2 and exits at FIG. 1H sheet 2.

FIG. 2 sheet 2 shows the body bending at the torso and blotting the moisture from the body. FIG. 2A sheet 2 is the sectional side view of the torso, FIG. 2B sheet 2 is the protective vest, while FIGS. 2C and D sheet 2 are supporting structures or in this case battens, and FIG. 2E sheet 2 shows the absorbent material blotting moisture from the back of the torso. When the wearer straitens his back the airflow will remove heat from the body through evaporative cooling. The surface area of the blotted area will be increased by removing excess beaded up moisture. Enhanced cooling will occur. As the wearer, straitens further the absorbent material FIG. 2E sheet 2 will absorb heat from the protective vest, FIG. 2B sheet 2. The air flow FIGS. 1G and H sheet 2 will remove heat through evaporative cooling from both the torso FIGS. 1 and 2A sheet 2 and from the protective vest FIGS. 1 and 2B sheet 2. The environmental heat will be hindered from absorption into the body by transfer of that heat from the protective vest FIGS. 1 and 2B sheet 2 by the absorbent layer FIGS. 1 and 2E sheet 2. This heat absorbed by this layer is continuously exhausted from the vest and away from the body by the flow of air and blotting action. The blotting action is continuous by making the plenum or space between the torso and the absorbent material small; in this case about 0.4 inch.

Absorbent material is anything that will transfer liquid water from a surface by contact. Cotton works well but so would dry wood or even plastic film would transfer beaded moisture from the skin surface. Any number of materials will work.

Blotting is the action of contacting a surface with the expectation that a material such as water or oil or fats will be moved from the first surface to a second surface. Blotting transfers sweat from one surface to another.

Supporting structures can be anything that holds the protective vest or blotting material or absorbent material off the surface of the body in this case to provide a plenum for the flow of air. Supporting structures can be a tube or a batten or a piece of padding. They can be arranged in any number of fashions.

The body or the torso is an integral part of a person and is of course often covered with a shirt or other covering. All of this being the torso or body. Moisture in the present invention is transferred often from a tee shirt that is in contact with the skin to the air flow in the plenum or could be transferred directly from the body.

Environmental heat is heat radiated or conducted from the immediate world about the person.

Moisture is water or in the case of the torso; moisture is sweat or the water component of sweat.

Auxiliary moisture is additional water added to any area of the vest to replace or add to the use of sweat as a moisture source. Auxiliary moisture is often pumped in with a squeeze bulb pump feeding a tubing network.

It is intended that further embodiments incorporating the spirit of the invention to one skilled in the art, fall within the scope of this invention.