Patent Grant
7721349
1. Field of Invention
This invention relates to the field of personal comfort devices, specifically, evaporative personal cooling devices that can be worn by humans or animals.
2. Prior Art
Throughout history, people have used various methods in attempts to keep themselves cool on hot days and in hot environments, especially when engaged in strenuous activities. Simple methods of personal cooling include wearing a moistened bandanna around one's neck, shading oneself with a hat or parasol, manually fanning oneself, using portable fans and/or misting devices, wetting or removing one's clothing, and changing into lighter clothing. All of these attempts have at least one of the following disadvantages:
With the development of modern technologies, new ways have been found to produce a portable cooling effect, including:
Still, each of these methods has serious drawbacks for the average user, due to cost, complexity, lack of portability, discomfort, difficulty of use, and/or lack of effectiveness. Most of these applications are ineffective because they require more energy than today's batteries can deliver beyond a brief period.
Because the evaporative cooling effect of water is simple and economical to harness, many personal evaporative cooling systems have been developed and refined over the years. U.S. Pat. Nos. 5,775,590 by Utter (Jul. 7, 1998) and 5,671,884 by Restive (Sep. 30, 1997) describe devices consisting of a portable water reservoir that, when pressurized by a user, propels water through a hose and out through a tiny nozzle, spraying the user with a fine water mist. By securing the device to the user's body with a belt or strap and by providing a clip that allows the user to direct the mist, these devices create a portable hands-free evaporative cooling effect. The disadvantages of this approach include: 1) the effect is very localized, 2) they wet the user's body and clothing, 3) they require the user to manually pressurize the bottle at intervals, 4) they require the user to move the nozzle to cool other areas of the body, and 5) because they do not use a fan, the cooling effect is minimal and inconsistent (a breeze is necessary for maximum effectiveness).
In an attempt to provide the needed moving air, there are a number of devices that allow the user to mist himself or herself while also employing a fan to move air across the moistened skin. U.S. Pat. No. 5,667,731 by Junket, et al. (Sep. 16, 1997) discloses a combination spray bottle and fan. It allows the user to spray himself with water while simultaneously directing the fan across the dampened skin. While this device makes up for the lack of moving air in the previously mentioned devices, it suffers from the remaining disadvantages already mentioned and additionally requires the user to hold the bottle and squeeze the trigger at intervals.
My U.S. Pat. No. 5,802,865 (Sep. 8, 1998) discloses a cooler that uses a fan to evaporate water from a powder-coated heat sink within the device and delivers the resulting coolness to the neck or forehead of the user without requiring the user to hold anything, do anything, or get wet. However, because this device is not flexible, it must be made to fit specific neck or head sizes and is not appropriate for other applications. The lack of flexibility also prevents this device from being used on a larger area of the body, and therefore does not cool the user nearly as much as would be desirable.
U.S. Pat. No. 6,371,388 by Utter, et. al (Apr. 16, 2002) discloses a device is that is strapped to the front of a user's body, and blows air mixed with a water mist up the front of the user's body. This approach has several disadvantages: 1) it wets the user's shirt, 2) because it blows over the user's shirt, it has little effect on cooling the user's torso, 3) it destroys the user's hairdo, 4) it requires the user to manually trigger the water spray, and 5) it is bulky, unattractive, and relatively expensive.
My U.S. Pat. No. 6,543,247 (Apr. 8, 2003) discloses a device that is strapped to the front or rear of a user's body and blows air mixed with a water mist up the front or back of a user's body under his or her shirt or blouse. This approach has the advantages of not wetting the user's clothes and, because the air/water stream is moving directly against the skin, produces a reasonable cooling effect over a larger area than most evaporative cooling devices. But this technique still has certain disadvantages, such as: 1) it does not cool the torso as much as desired, 2) it wets the user's skin, 3) inexpensive embodiments require the user to trigger the water spray manually, 4) it cannot cool the back of a hiker wearing a backpack, and 5) it cannot cool users who are wearing motorcycle leathers, protective suits, or tightly fitting clothing.
U.S. Pat. No. 6,257,011 by Siman-Tov, et al. (Jul. 10, 2001) reveals a portable lightweight cooling garment having a channeled sheet that absorbs sweat and/or evaporative liquid, a layer of highly conductive fibers adjacent to the channeled sheet and a device for moving air through the sheet. U.S. Pat. No. 6,134,714 by Uglene (Oct. 24, 2000) discloses a personal cooling garment with inner and outer layers defining a confined space for containing liquid that can evaporate to create a cooling effect. The drawback of both approaches is that they do not increase the surface area beyond what is provided by the user's skin, and therefore can only make the evaporative cooling effect somewhat more consistent, but not more cooling than perspiring on a breezy day.
U.S. Pat. No. 5,755,110 by Silvas (May 26, 1998) describes a cooling vest having a plurality of elongated pocket partitions containing beads of polyacrylamide. These absorb liquid to form a gel that may be chilled or frozen to provide a cooling effect on the upper torso of a human wearer. The problem in all such approaches is that the cooling effect is neither as strong as desired nor as long-lasting as users would wish.
Accordingly, several objects and advantages of the present invention are to provide an improved evaporative personal cooling device that:
Further objects and advantages will become apparent from a consideration of the drawings and ensuing description.
A system for cooling the skin of a human or animal user includes:
a is close-up view of a cooling element penetrating a primary reservoir.
b is a close-up view of a section common to fan-free embodiments.
a shows a fan-free headband embodiment not being worn.
b shows the headband embodiment of
c shows a fan-free T-shirt embodiment for cooling a user's torso.
d shows a fan-free vest embodiment for cooling a user's torso.
e shows a fan-free elastic shorts embodiment.
f shows a fan-free embodiment for cooling a user's neck.
g shows a fan-free embodiment for cooling a user's forearms.
h shows a fan-free sneakers embodiment for cooling a user's feet.
i shows a fan-free baseball cap embodiment for cooling a user's scalp.
j shows a close-up of special element extensions for penetrating hair or fur.
k shows a fan-free cooling blanket embodiment
l shows a fan-free embodiment for cooling a dog.
a shows one way of creating a reservoir for storing additional fluid.
b is an edge view showing the additional fluid reservoir of
c is a front view of a soft, clear, sponge-filled additional fluid reservoir.
d is a top view of additional fluid reservoir sitting on top of elements.
e is a top view of additional fluid reservoir in direct contact with primary reservoir.
f shows additional fluid reservoir as a hard, clear box.
g shows additional fluid reservoir as a sponge.
a shows an edge view of an element having an alternate shape
b shows a snap-together two-part element.
c shows a snap-together two-part element with a spherical top.
d shows a snap-together two-part element with extra surface area.
e shows a special tool for inserting two-part elements into existing articles.
f shows a two-part removable snap-together system.
g shows a two-part removable screw-together system.
h shows a two-part removable clip-together system.
i shows an edge view of a corrugated element strip.
j shows corrugated element strips used in a vest embodiment.
k shows a perspective view of an egg-crate deformed element.
l shows a vest embodiment using several egg-crate deformed elements.
m shows a vest embodiment using a single egg-crate deformed element.
n is a close-up perspective view of a 4-pronged element with elastic connectors.
o is a top view of a group of 4-pronged elements connected together.
p shows a group of 4-pronged elements connected using an elastic fabric.
q shows a group of elements connected using elastic, fluid-wicking parts.
a shows a forced air headband embodiment not being worn.
b shows a user wearing a forced air headband embodiment.
c shows a forced air embodiment for cooling the forehead and the scalp.
d is a top view of a user wearing the device of
e shows a user wearing a forced air vest embodiment.
f shows an additional reservoir sitting on elements in a forced air embodiment.
g shows an additional reservoir sitting on the primary reservoir in a forced air embodiment.
h shows a forced air baseball cap embodiment.
i shows a forced-air cooling blanket embodiment.
j shows a forced-air motorcycle jacket embodiment.
k shows a forced air hard hat embodiment.
l shows a forced air motorcycle helmet embodiment.
m shows a thermostatically controlled forced-air vest embodiment.
n shows a thermostatically controlled embodiment with multiple zones.
o shows the primary reservoir on top of the cooling elements.
p shows primary reservoir on top of the cooling elements with rounded element bottoms.
q shows primary reservoir at both the top and the bottom of the cooling elements.
a shows a forced air shirt embodiment designed to be used under an existing T-shirt.
b shows the device in
c shows an embodiment designed to be worn under an existing baseball cap.
Overview of the Cooling System and its Three Primary Expressions
My personal cooling system combines a unique, flexible heat sink with a method of maximizing the evaporative cooling effect. There are three basic expressions of the system, each of which has many possible embodiments:
Fan-free embodiments are the simplest; all other expressions start there and provide additional features and benefits.
Referring to
I've experimented with many approaches to maximizing the effectiveness of each ingredient and will mention in this section only the currently most favored solution; other approaches will be mentioned in the section titled “Embodiment #1: Alternative Methods”.
Reservoir 100 is preferably made of a nylon/spandex or cotton/spandex fabric. Other materials that can be used include woven or nonwoven fabrics, foamed, porous, or laminated materials, etc. Reservoir 100 preferably provides a linear path for capillary action (vs. random path wicking provided by foamed materials) to effectively wick water vertically. Reservoir 100 not only wicks and holds water, but also provides a flexible backbone for the device.
One of the simplest and most effective ways I've found to flexibly interconnect elements 120 while simultaneously keeping them moist is by having elements 120 penetrate through slits 104 in an elastic, absorbent fabric that functions as reservoir 100 for water or other cooling fluid. When reservoir 100 is wet, water migrates onto fluid-wicking surfaces 124 of elements 120 and evaporates, transporting heat from elements 120 into the surrounding air.
Elements 120 are both thermally conductive throughout and fluid-wicking on at least portions of their surfaces. They are preferably formed of rectangles (heat sink radiation fins) of high-purity aluminum (for maximum heat transfer combined with low weight and cost), having dimensions of approximately twenty five thousandths of an inch thick by one quarter of an inch wide by one inch long. Each fin is formed into a square “U” shape, inserted through slits 104 in reservoir 100, and the two ends are curved toward each other and down toward the inside bottom of the “U”, whereby element 120 mechanically attaches itself to reservoir 100 in the manner of a staple. This approach:
My experiments show that the most effective approach for promoting water to wick across surface 124 of elements 120 is to create a series of densely packed crosshatched grooves on both surfaces of each fin. The original aluminum sheet should first be mildly abraded, and the grooves should be approximately two and a half thousandths of an inch wide and at least the same in depth, and should be as close together as possible. Of the many ways to form such grooves, micro-deformation using finning discs is currently the favored process because it is highly effective and inexpensive.
b shows a section view of reservoir 100 with four elements 120. Reservoir 100 can be made of any strong, flexible, preferably elastic, rapidly wicking and highly absorbent material such as nylon/spandex or cotton/spandex fabrics. In most embodiments, for the sake of the user's comfort, reservoir 100 is preferably less than one tenth of an inch thick.
Reservoir 100 can have a continuous outer reservoir barrier 101 on the outside-facing surface to prevent water from evaporating directly from the fabric into the air, rather than from the surfaces of elements 120, thereby conserving water and prolonging the cooling effect before rewetting. Alternatively, outer reservoir barrier 101 can be discontinuous, providing some protection from evaporation while still allowing the user to wet reservoir 100 directly.
Reservoir 100 can (and, in most cases for comfort should) also have an inner reservoir barrier 102 on skin-facing surface 125 to prevent moisture in reservoir 100 from wetting the user's skin. To insure a completely waterproof seal, inner reservoir barrier 102 can cover both primary fluid reservoir 100 the skin-facing portions of elements 120. However, this creates the problem that almost any waterproof barrier, no matter how thin, also tends to act as a thermal insulator, reducing the cooling effect. Experiments show that a comfortable, waterproof, elastic barrier can be made by filling inner reservoir barrier 102 with aluminum powder (or other thermally conductive material), thus greatly increasing its thermal conductivity.
If both the inner and outer surfaces of reservoir 100 have a continuous moisture barrier, special means must be provided for the user to wet reservoir 100. This can include wetting:
a shows a headband embodiment prior to being worn. A grid of elements 120 penetrate reservoir 100 as previously described, and inner reservoir barrier 102 (not seen in this view) protects the user's skin from being wet. Outer reservoir barrier 101 keeps water from evaporating directly into the surrounding air, forcing all of it to migrate onto surfaces 124 before evaporating. Hook-and-loop fasteners 131 at each end allow the user to secure the device to his or her forehead.
Different embodiments can provide different ways to soak reservoir 100, such as by immersing the device in a basin of fluid, by dousing it with a hose, or by squirting or spraying it with liquid from a container. In the embodiment shown in
Once reservoir 100 is wet, fluid will migrate onto fluid-wicking surfaces 124 of elements 120 by capillary action. Because the fluid is spread in a very thin layer over a relatively large surface area, the surrounding air has easy access to the molecules of water, and readily absorbs it according to the air temperature and humidity. As the evaporating water is carried into the surrounding air, it carries with it heat that was in elements 120. As elements 120 cool, they absorb heat from the user's skin, thereby cooling the user.
If the device was made elastic to fit a range of body sizes, it can simply be slipped on and adjusted for comfort. For example,
The flexibility of the device allows it to be configured to comfortably cool almost any part of a human or animal body.
d shows a user wearing a cooling vest embodiment. To prevent the user's clothing from being wet by contact with the edges of the device, device edges 105 can be sealed in a number of ways, including:
e shows a user wearing an elastic shorts embodiment.
Embodiments for human users that can be worn as clothing include long and short sleeved shirts or blouses, shorts, pants, jeans, jackets, vests, dresses, skirts, jumpsuits, robes, bathing suits, sleepwear, hosiery, athletic wear, uniforms, and costumes. In short, the device can be embodied as virtually any article of clothing. Accessory embodiments can include coolers for the head, neck, shoulders, chest, back, upper arms, lower arms, wrists, hands (gloves), upper legs, lower legs, and feet (boots, shoes, and sandals).
Hats, caps, and hoods provide a particular challenge. The hair covering human heads makes it difficult to deliver cooling relief to the scalp.
A full-body jumpsuit embodiment can be created with many detachable parts. The collar can be detached; the forearm pieces, upper arm pieces, lower leg pieces, etc., according to the user's need in the moment. In extremely hot environments, the suit can even incorporate an elastic hood that detaches from the collar piece or can be pulled off the head.
People often need to wear protective clothing or helmets that create extra discomfort in heat. Workers required to wear gear for protection from an array of dangers (including radiological, biological, physical, thermal, and chemical hazards) would all benefit from the ability to control their thermal comfort while remaining safe. Technicians and industrial workers (welders, sandblasters, coatings sprayers, etc), firefighters, rescue workers, chemical and biohazard remediation personnel, military and law enforcement people wearing body armor are among many who would benefit greatly from the ability to stay cool on the job. Workers wearing uniforms are also often made very uncomfortable in hot weather and conditions. And today, people all over the world are forced to wear long shirts and pants to protect themselves from increasingly harsh solar radiation.
In situations where mild or less predictable cooling is acceptable, or where the extra visual bulk of forced-air embodiments is unacceptable, fan-free embodiments of the device can be created to protect a user's body from hazards while also providing cooling. The primary key is the material used as outer reservoir barrier 101 (shown in
If double protection is needed, inner reservoir barrier 102 can also be made of a protective material. If triple protection is needed, reservoir 100 can itself be composed of protective material, provided it is both flexible and absorbent as well as preferably elastic. The points of intersection between elements 120 and reservoir 100 must be carefully sealed to prevent hazardous materials, gasses, or radiation from leaking through to the user's skin. In this case, the two-part version of elements 120 discussed later may work better.
In the case of a chemical protection suit, reservoir barriers 101 and/or 102 can, for example, be latex, polyethylene, ethylene-vinyl alcohol, multi-layered film barrier composites, soft polypropylene laminated fabrics, aromatic polyamides, or any of the hundreds of different materials currently used to resist chemicals. If the device is used to protect against chemicals that can react with whatever material comprises elements 120, the surface of elements 120 can be treated for protection from such chemicals or elements 120 can be made of a material that will not react with the chemicals in question.
An embodiment providing physical protection for motorcyclists can use leather as outer reservoir barrier 101, thereby offering physical protection along with effective cooling power. An alternative fan-free motorcycle jacket can be created by combining a fan-free shirt embodiment to be worn against the skin with a leather jacket providing vents in the front and the rear. When a biker is on the road, wind will rush into the device through the front vents, evaporate water from the surfaces of elements 120, and exit through the rear vents.
I also anticipate fan-free helmet embodiments designed to make use of the air rushing past a bicyclist or motorcyclist when in motion. Air intake vents can be slits toward the front of the helmet, funneling the moving air directly to the tops of elements 120. Slits in the rear of the helmet will allow the rushing air to escape, thereby freeing the device of any need for fans or batteries.
Many people have the problem of living in climates so hot at night that it's difficult to sleep. Fans can cool a user, but it can be disturbing to have air moving across the body when trying to fall asleep. Many people are made uncomfortable by having to remove all covers in order to be cool enough, and tend to use at least a sheet, even if that makes them hotter. Air conditioners work well, but also create potentially annoying air movement and noise, and are expensive to run all night. A fan-free or forced-air embodiment in the form of a blanket or sheet would allow users to simultaneously feel cozy and stay cool, without having air moving against their skin, paying for air conditioning, or being irritated by the noise of a large fan or air conditioner.
k shows a fan-free cooling blanket embodiment. As usual, there is a reservoir 100 in the form of a flexible, absorbent fabric, studded with a grid of elements 120. As previously described, the skin-facing surface of the blanket is coated with a flexible, waterproof, thermally conductive inner reservoir barrier 102, not shown in this view. Element-free zone 223 is provided because elements need only be closer to the center, where the user's body is likely to be. The user would simply pour a glass of water on the center of the blanket and get cozy. The water will rapidly migrate throughout reservoir 100, onto the fluid-wicking surfaces 124 of elements 120, and evaporate into the surrounding air, thereby cooling the user.
Many dogs have been bred with long hair for colder environments, but are raised and cared for by owners who live in warm or hot environments. Additionally, pet owners often face the challenge of needing to leave a dog in a locked vehicle with the windows closed for security, but want to protect them from too much heat if the vehicle is parked in the sun. Other animals are often exposed to excessive temperatures, especially during heat waves, and their owners would like to keep them cool.
The main problem in cooling animals is that, as with the hair on human heads, their fur acts as a thermal insulator, preventing the evaporative cooling effect of water from fully reaching their skin. None of the evaporative cooling devices mentioned in the cited prior art would work for a fur-covered animal. Devices that spray water and/or blow air would have a negligible effect.
l shows an embodiment for cooling a dog. Except for its shape and a few other details, it provides essentially the same solution for dogs and animals as the baseball cap in
Fan-free embodiments can be used for both cooling and warming, according to the needs of the user. On a hot day, a user can wear one set of clothes that will maintain thermal comfort day and night, indoors and out. A user can put on a fan-free long-sleeved shirt embodiment and a fan-free jeans embodiment and head out into the sun. Because the plurality of cooling elements creates a huge surface area from which moisture can evaporate (thereby removing more heat than is removed through perspiration), the user will actually be cooler under the heavier cooling clothing than if he or she had ventured out with no clothing at all.
If a user steps into an air-conditioned building, he or she need only throw an extremely light outer covering over the shirt and/or jeans, and suddenly not only can the water no longer evaporate, but the thermal insulation provided by reservoir 100, outer reservoir barrier 101, inner reservoir barrier 102, air space 165, and the thin outer shell will act as a jacket, quickly warming the user. An outer layer to be thrown over the device can be sold as an integral part of the system and can also be packed into a tiny bag or be kept in a pouch or pocket that is part of the device. Whether the user throws on an outer shell that is designed to be used with the device, or uses an existing article of clothing, they should block all potential air exits by buttoning the wrists, tucking in a shirt or blouse, etc. to prevent air from circulating around elements 120, thereby reversing the desired warming effect.
There are many ways to store the water (or other cooling fluid), distribute it, and wet reservoir 100 as well as elements 120. In the embodiments discussed so far, water was stored in primary reservoir 100, which automatically distributed the moisture by capillary action to elements 120. To wet reservoir 100 in the devices so far described, the user can douse the device in a sink or other body of water, spray it with a hose, or wet it by sparing with a stream or spray of liquid from a bottle.
However, such wetting methods have serious drawbacks, such as that the user might:
There are several ways to resolve these problems.
Running through the length of additional reservoir 110 is a long notch 114. Attached to the entire bottom of additional reservoir 110 is a piece of wicking material 118 serving as reservoir bottom 222, such as a piece of tightly woven cloth or a thin piece of porous plastic, which provides a way for water to be channeled to both ends, rather than splash directly onto elements 120 and/or reservoir 100. Material 118 also creates a wicking interface between sponge 112 and the tops of element 120. Attached to the entire top of additional reservoir 110 is a piece of waterproof material (in this case, a clear flexible plastic) functioning as reservoir cover 220. In the center of reservoir cover 220 is a long oval reservoir opening 221. A user can take an external reservoir 109 such as a water bottle with a pointed top, insert it into the slot exposed by reservoir opening 221, urge it toward the front end of reservoir opening 221, and squeeze. Water will flow from external reservoir 109 into notch 114, and as it runs downhill it will be absorbed by sponge 112 on each side. The user can then slide the tip of the water bottle back until it hits the back end of reservoir opening 221, and squeeze again to wet the sponge in the back part of additional reservoir 110.
b shows a section view in which reservoir 110 sits on top of elements 120. Alternatively, elements 120 can be kept outside the area where reservoir 110 is located, allowing reservoir 110 to make direct contact with reservoir 100.
As long as they absorb water, additional reservoir(s) 110 can be rigid or soft, and can be filled with an absorbent material such as a sponge 112, or not.
f shows additional reservoir 110 as a stiff clear plastic box not filled with a sponge. A user can remove reservoir cap 113 and squeeze water into reservoir 110 from a bottle. Holes 117 in reservoir bottom 222 allow water to drip onto wicking material 118, which transfers the moisture by capillary action to the tops of elements 120, directly to reservoir 100, or both. Of course, holes 117 can be in the back of additional reservoir 110, with wicking material 118 inserted as a wicking interface between the back of the reservoir 110 and the tops of elements 120. Alternatively, reservoir 110 can be shaped so that holes 117 are in direct contact with reservoir 100, so that no other wicking material 118 is needed.
Additional reservoir 110 can be made detachable from the device so instead of squirting water into it, it can instead be submerged in a body of water or placed under a spigot. In another approach, if reservoir 110 has a sponge 112 and a cover 220, the user can open a door, pull out sponge 112, soak it in water, place it back inside reservoir cover 220, and close the door.
The fewer the number of additional reservoirs 110 provided for the user to fill, the more convenient it will be for the user, yet the more important it will be for either reservoir 100 or any fluid delivery means to promote water to wick across the entire length of the device. Ideally, each device would have just one or two additional reservoirs 110. Having just one or two reservoirs 110 also provides a minimum number of points from which the water level can be monitored. In a low-tech water monitoring approach, the user can simply look through clear reservoir cover 220 and see if more water is needed. To make dryness more obvious, sponge 112 can be impregnated with cobalt chloride or any chemical that turns a different color when wet vs. when dry. In a high-tech approach, the system can electronically detect when the system is low on water (such as by measuring electrical resistance between two points on the device) and can activate an alarm, blinking light, voice notification, etc., alerting the user to add water.
The device can incorporate means to manually or automatically spray water stored in additional reservoirs 110 onto elements 120, but any such approach would likely be far more complex and far less practical than the various capillary distribution means already discussed. If automated means are used, it can include commonly available means to determine when extra water is needed.
Assuming capillary or wicking action is used, water will be drawn automatically from the reservoir to drier parts of the device as needed. Alternatively, instead of being essentially sponges, additional reservoir(s) 110 can be watertight bottles from which fluid can drip or flow by gravity through tubes or channels that connect additional reservoir(s) 110 to various parts of the device. If the system depends on gravity to deliver the water (a more complicated and less efficient solution), the user will need to manually turn the water delivery system on and off, or an automatic system will be needed that can sense the dryness of an area and activate valves to start and stop water flow. This configuration would also require additional reservoirs (110) to have watertight lids, an extra hassle for the user to deal with.
a shows a variation on the shape of elements 120, in this case to add more surface area. Elements 120 can have any shape as long as they wick fluid and conduct heat.
In
c is essentially the same, but has a more rounded top part 122 to make the outside of the device smoother to the touch.
A permanent two-part element system can be created as a do-it-yourself kit, allowing consumers to turn existing garments or accessories into cooling devices.
f-h show three different ways to make a removable two-part element system that would allow users to manually insert elements 120 without a special tool. All three are based around a central pin-like stud that will penetrate through the fabric of an article of clothing without tearing it.
g show a system in which the sharp protrusion from bottom element part 121 is a male threaded stud 203, and top element part 122 has a female threaded socket 204 to receive it. The user simply presses bottom element part 121 through the article of clothing, then threads top element part 122 onto it.
h shows bottom element part 121 as a simple pointed stud with a slightly protruding ridge 208 that keeps top element part 122 from being easily pulled off bottom element part 121. Top element part 122 is much like a binder clip; it has two fluid-wicking fins 205, a “C” spring 206, and clip jaws 207. Fluid-wicking fins 205 must either be stuff enough to withstand being squeezed together many times by the user, or must be framed around the edges with a very stiff material. “C” spring 206 functions to hold top element part 122 to bottom element part 121. Clip jaws 207 are curved to make solid thermally conducting contact with bottom element part 121. The user simply presses bottom element part 121 through the article of clothing, then clips top element part 122 onto it.
In all three approaches, top element part 122 and bottom element part 121 must be created to mate closely to maintain maximum thermal conductivity between them. Top element part 122 must have wicking surfaces that will make a wicking contact with clothing article 164 when installed. Once the user has installed a plurality of elements into the article of clothing, he or she will put the article on and wet it. Water from the clothing will wick onto the fluid-wicking surfaces of top element parts 122 and evaporate, cooling the user.
Neither top element part 122, nor bottom element part 121, nor a single-piece element 120 can be made too large before it starts detracting from the flexibility and comfort of the device. However, if elements 120 are corrugated, they will themselves become flexible and can therefore be made much larger.
i shows how by taking strips of aluminum, making capillary micro-grooves in the surface (not seen in this edge view), and corrugating them in two dimensions (like the inside layer of corrugated cardboard), elements 120 can cover larger areas of the body while remaining flexible. The flexibility, however, is limited to one dimension, therefore any device making use of such corrugated strips will need to limit the width of each strip both for the user's comfort as well as for the sake of maintaining maximum contact between skin-facing surface 125 of the device and user's skin 150.
j shows a cooling vest made of such corrugated, fluid-wicking aluminum strips 126. In this configuration, the fluid storage and wicking functions performed by primary fluid reservoir 100 in previous embodiments are now assumed by the flexibility and fluid-wicking ability of 2-D corrugated element strips 126 themselves. Because little fluid can be stored in the capillary micro-grooves of elements 120, additional fluid reservoirs 110 (absorbent fabric or fluid-wicking foamy material) are provided. By placing them at the edges of the device, additional fluid reservoirs 110 double as a way to finish the sharp aluminum edges of strips 126 with a soft material that is comfortable to the skin.
It is desirable to keep the overall design elastic in order to maintain skin-facing surfaces 125 of elements 126 in contact with user's skin 150. To accomplish this, 2-D corrugated element strips 126 are connected via elastic connectors 115, preferably absorbent elastic fabrics. Fluid-wicking surfaces 124 face the outside, and skin-facing surfaces 125 are placed against the user's skin. When a user wets additional fluid reservoirs 110, water quickly spreads by capillary action onto the surface of 2-D corrugated element strips 126 and evaporates directly into the surrounding air. As with the previously described embodiments, the reason this improves on natural perspiration is because the corrugations in elements 120 create a surface area greater than the user's skin, thereby making much more water available at the surface for evaporation, which in turn increases the heat pump effect.
As previously mentioned, the disadvantage of 2-D corrugated element strips 126 is that they are not flexible in three dimensions.
l shows how, as in
m shows how a cooling vest can be made from a single sheet of 3-D corrugated, fluid-wicking, thermally conductive material. Once the main body of the vest is formed, a manufacturer need only add additional fluid reservoirs 110 and hook-and-loop fasteners 131. One or more elastic belts 116 can also be provided to maintain contact between the device and the user's skin.
In the approaches described using corrugated materials, only the outside-facing surface of the device is treated or created to promote the wicking of a fluid. In another variation, skin-facing surface 125 of the device can also be created or treated to promote the wicking of water, with means to allow water to migrate from one surface to the other. A simple way to accomplish this is to make the device of a thin piece of aluminum with crosshatched grooves that penetrate more than 50% of the thickness on both sides. By making the grooves horizontally on one side, and vertically on the other, small gaps will be formed where the grooves intersect in the center of the thickness, allowing water to migrate from on side to the other. This configuration permits the user's own perspiration to add to the moisture being evaporated on the outside surface of the device. The drawback is that water added to the outside surface will be wicked onto the user's skin, creating potentially uncomfortable sensations.
The benefit of using a corrugated or deformed thermally conductive material created or treated to wick water is that it is extremely inexpensive to produce. The drawback is that it is far less flexible than the approach of interconnecting smaller elements 120 with a flexible material (such as a spandex fabric) as previously described, and is therefore less comfortable for the user.
In systems using both the 2-D and the 3-D corrugation embodiments just described, the more peaks and valleys per inch, and the taller the peaks and valleys, the greater the surface area and therefore the greater the cooling effect. A limit will be found, however, whereby the corrugations are so tight that air cannot move efficiently between the walls, and the evaporation rate will reach a practical maximum. In either approach, holes can be cut or punched in the aluminum sheet either before or after any of the other processes, to allow the user's skin to “breathe”.
In the previously described embodiments, the system derived its flexibility from the fact that elements 120 were joined by reservoir 100, which is at least flexible and preferably elastic. A variation just described provides flexibility by making corrugations or deformations in elements 120.
The limitation of this configuration is that, without reservoir 100 or some other means to convey water between the elements, there is no obvious way to wet elements 120 and keep them moist. As previously mentioned, the device can incorporate means to manually or automatically spray water on elements 120, but any such approach is far more complex and tedious than by supplying water as previously described through a flexible reservoir such as an elastic fabric. Additional reservoirs can be suspended in the blank squares between elements 120, but that is almost the same as returning to embodiment #1, with elements 120 being supported by reservoir 100.
p shows a method that provides flexibility while also storing and distributing water and letting the user's skin breathe. Elements 120 penetrate the edges of elastic wicking fabric 115 (or other elastic wicking material), which stores water and wets both the inside and outside surfaces of elements 120. The square spaces between fabric 115 and elements 120 give the user's skin access to the surrounding air. This approach is essentially the same as was described in Expression #1 embodiments if holes had also been punched through reservoir 100.
g shows another variation in which elastic connectors 125 can be any material that is both fluid-wicking and flexible (preferably elastic), such as foam, elastic fabric, porous rubber, or porous elastomeric plastics. The resulting device will have air spaces that allow the user's skin access to the surrounding air so it can breathe. In this approach, water will be forced to migrate from one element to the next through elastic connectors 125.
Elements 120 preferably penetrate reservoir 100 and are secured to it by any effective means, including glue, or by virtue of the shape of elements 120 gripping or interlocking with reservoir 100 as discussed above. However, elements 120 do not need to penetrate reservoir 100; they can be attached to the edges of holes punched in reservoir 100. In either case, contact between elements 120 and reservoir 100 must allow fluid from reservoir 100 to migrate directly onto the surface of elements 120 by capillary action.
Elements 120 can also be made of a foamed thermally conductive material (such as foamed aluminum), which would serve two purposes: 1) to wick fluid up the elements for evaporation, and 2) to transfer heat from the skin to the evaporating fluid. However, the foamed aluminum available today is either far too expensive or not porous enough to wick water. In any case, it is anticipated that foamed aluminum or copper would not perform the thermal conductivity function as well as solid aluminum or copper with a micro-grooved surface.
Treatments to promote water to wick across the surface of elements 120 include but are not limited to:
Option 1 is inefficient because in general the coating itself acts as a thermal insulator, allowing water to evaporate, but reducing the heat transfer effect. Option 2 is technically difficult to produce and is not likely to be useful because anything printable on the surface (even aluminum powder) would need to include binders, which are at least mildly thermally insulating. For option 3, one of many effective capillary powder coatings can be made by adhering 100 mesh silicon carbide grit (commonly used for sandblast etching) to the surface of the aluminum elements using a urethane-based glue. Option 4 is not as effective as option 5 because it provides less surface area from which water can evaporate.
Option 5, described earlier as the preferred method, is by far the most effective because it does not insert any thermally insulating substances (such as glues, inks, powders, or granules) between the thermally conductive elements and the air. In addition, the cross-hatched or crisscrossed groove pattern provides for maximum water to migrate onto the surface for evaporation.
Micro-deformation using finning discs was earlier described as the preferred method of creating surface grooves. Such grooves can alternatively be formed by means of engraving, micro-machining, laser cutting, wire EDM (electrical discharge machining), and other methods. Grooves or channels can also be created by composing the elements of innumerable layers of extremely thin material, such as alternating widths of thin aluminum. When the layers are fused or adhered, the narrower layers form the bottoms of the capillary channels, while the wider layers form the walls of the channels. Such a process, however, is not likely to be cost effective.
An alternative way to prevent water from leaking onto the user's skin is to provide fluid-wicking surfaces on elements 120 only on the outside-facing areas of reservoir 100, but not continuing through to skin-facing surface 125. This approach, however, is not as waterproof as that mentioned just above. It would also be difficult to manufacture elements 120 using finning discs such that the cross-hatched grooves stop short of the skin-touching areas.
The combination of reservoir 100 plus any additional reservoir barriers 101 and/or 102 must be strong enough to withstand the stresses of normal use when worn by a user. To help maintain tensile strength, each row of elements 120 can be offset so that slits 104 in reservoir 100 don't line up, since aligning them would effectively create an easy-to-tear perforated line. Other approaches can be employed to strengthen the device, such as by reinforcing reservoir 100 with a strong, flexible material at various points within and/or around the edges of the device. If such material also had wicking properties, it can double as an additional reservoir 110.
Problems can be created if elements 120 are placed in areas of the device that might come in contact with objects, such as the back of a chair or car seat. Solutions include:
Also, to prevent water in the device from wicking onto external objects, such as a car seat, or a fabric chair, pants bottoms, shirt backs, or vest backs can be isolated from the rest of the device.
If the stiff material for distributing weight were continuous (as in a thin sheet of plastic), it would have the effect of preventing the surrounding air from moving freely around elements 120, which would mediate the cooling effect. Using a fan to move the air in such areas would turn that area of the device into a forced-air embodiment as described next. If the stiff material for distributing weight were discontinuous (such as with a stiff plastic mesh), it can allow air to continue to circulate around elements 120 without the need for a fan.
The above-described fan-free embodiments are ideal for use in situations where:
When consistent, maximum cooling is needed, forced-air embodiments provide an ideal solution to the problem of maintaining maximum cooling comfort in hot temperatures. Forced air embodiments fall into two categories: 1) embodiments in which an external air barrier to confine airflow to the area surrounding elements 120 is integrated, and 2) embodiments in which an existing article of clothing, accessory, or piece of gear is used as the external air barrier. The former is discussed as Expression #2; the later will be discussed later as Expression #3.
a illustrates a simple forced air embodiment for cooling the forehead. Comparing this with
Referring to
c depicts a forced-air embodiment that cools the forehead as well as the scalp around the sides and back of the head. As previously described, a fan 170 is provided, along with a plurality of elements 120 that penetrate reservoir 100 into air space 165 formed by barrier 160. In this embodiment, the skin-facing surfaces of elements 120 around the sides and back of the head have the same kind of rounded, rod-like extensions described for the fan-free baseball cap (
e shows the device embodied as a forced-air cooling vest. The principle is the same as depicted in the cooling headbands described above, but here reservoir 100 and elements 120 cover the user's entire torso. Additional fluid reservoirs 110 provide centralized locations for the user to insert water, which migrates throughout the device, feeding moisture to elements 120. Additional fluid reservoirs 110 provide an easy way to wet the device. Sponge 112 has notch 114, which increases sponge surface area, allowing it to absorb water as quickly as it is being inserted. A user would insert the tip of a water bottle into reservoir opening 221 and squeeze; the water will move through notch 114, rapidly wetting sponge 112, and, through capillary action, will also wet all of reservoir 100. Fans 170 draw air into the device through air intake vents 166 at the edges of the vest and circulate air through air space 165, speeding evaporative cooling from elements 120.
Backpackers have the problem of needing to cool their back, but unless the backpack is held away from their body by a frame or spacer, the fan cannot be located on the back because it would be blocked by the pack. In this case, a vest such as the one depicted in
f and 5g show reservoir 110 from above. Reservoir 110 interfaces with elements 120 either by sitting on top of elements 120 as in
In all Expression #2 embodiments, outer air barrier 160 itself can fulfill the function of additional fluid reservoir 110 simply by making it of a wicking material. Such a wicking material can also be coated with a waterproof material either to prevent water from evaporating directly in the surrounding air or to prevent the outside of the device from wicking water onto anything the user may be leaning against.
h shows the device embodied as a forced-air baseball cap. Comparing this with
i shows a forced air blanket embodiment. Fan 170 can be run using either battery 172 or power from a wall outlet. The user would add water to additional reservoirs 110, turn on fan 170, and enjoy cooling comfort all night. If needed, a very thin piece of soft fabric can be provided to keep skin-facing surface 125 of the blanket (not shown) from touching the user's skin, making it feel cozier to the user.
Just as with clothing, the idea that a blanket can actually cool, rather than warm, a user may seem fairly radical. Once the idea is embraced, however, it's easy to see how this method can easily be applied to shawls and wraps. People are often uncomfortably hot and may not wish to change into clothing embodiments of the device to get cooler. In such instances, using a fan-free or forced-air embodiment such as a shawl, scarf, or wrap can bring welcome, cooling relief.
A forced-air pet cooler very similar to the version depicted in
In situations where consistent, maximum cooling is needed along with hazard protection, forced-air embodiments can be created in which outer air barrier 160 is made of whatever material is necessary to protect the user from physical, thermal, chemical, biological, or radioactive hazards. If double or triple protection is needed, outer reservoir barrier 101 and/or inner reservoir barrier 102 can also be made of whatever protective material is needed. If quadruple protection is needed, reservoir 100 can itself be made of any flexible and absorbent protective material, which is preferably also elastic.
In protective garments to be used in extremely hazardous situations, the device may need to keep external air from touching the skin of the user. For these devices, the entire air stream as it enters the device, travels around elements 120, and exits the device, must be isolated from the user's skin as well as the air the user is breathing.
j shows an integrated forced-air embodiment providing physical protection for bikers. This device uses leather as outer air barrier 160, which forms motorcycle jacket shell 184. Fan 170 is located in the middle of the back, and air intake vents 166 are located near all edges of the device. Beneath motorcycle jacket shell 184 is an inner layer like that depicted in
Construction workers, cyclists, and other people wearing helmets would also appreciate being cooled in hot weather.
k shows a motorcycle helmet embodiment. Helmet 182 has a thick layer of foam padding 183 inside, which can double as additional fluid reservoir 110. Water can be added from the bottom side of elements 120 (with cooling element extensions 123 now shown) or through one or more holes in the top of helmet 182. As water soaks through foam padding 183, it migrates onto and across fluid-wicking surfaces 124 of elements 120, and into primary fluid reservoir 100. When the user turns on fan 170, air is drawn in through air intake vents 166, across elements 120, and out through fan 170, cooling the user's head. In another variation, elements 120 are attached directly to foam padding 183, eliminating the need for reservoir 100 as a means to support elements 120. In this configuration, foam padding 183 itself acts as the primary fluid reservoir and, because of its thickness, can hold a tremendous amount of water.
m depicts a thermostat-controlled jacket. Thermostat 140 is connected to a temperature sensor 141 on the inside of the device, a control circuit 142, and fan 170 (not shown; in the center of the back). When a user sets the thermostat to a desired temperature, control circuit 142 will respond as follows:
If control circuit 142 turns off fan(s) 170 to stop the cooling action, it can also trigger the blocking of all open edges of the device with controllable edge air barriers 162 to speed the internal warming of the device. Controllable edge air barriers 162 can be opened or closed by any suitable means, such as by inflating plastic “balloons” along the edges, thereby sealing the air vents, or by using mini servo-motors, linear actuators, or nitinol-type wires (or other material that expands or contracts with the application of an electrical charge) to mechanically slide or close flaps. The edges might also be blocked without the use of a control circuit by using vents with very lightweight flaps that stay open only when a fan or other air-moving device is forcing air through them.
A similar effect can also be achieved without the use of a control circuit. Thermostat 140 can be used as a mechanical switch for fan(s) 170 in the same manner that analog thermostats control home furnaces. But an advantage of having a control circuit is that it can sense the rate of change of the user's skin temperature and adjust the speed of fan(s) 170 accordingly, thereby creating a stable thermal environment that does not subject the user to rapid changes in temperature that would result if the device is either on or off. This will be a great boon to users who are extremely sensitive to sudden or even slight temperature changes.
Referring to
Barriers 162 can be closed manually by blocking the air intake and exhaust areas. This can be accomplished by tightening a drawstring, closing a flap, zipping two flaps together, clipping one part to another, etc. Options that can be activated either manually or automatically include pivoted flaps, sliding flaps, rotating vents, interconnecting cells with parallelogram shapes that stand up or collapse as a unit, and inflatable “balloons”, etc.
If, in a thermostat-controlled embodiment, outer air barrier 160 were itself a thermal insulator (such as down, wool, fleece, fur, synthetic insulation, etc.), the range of temperatures that a warming/cooling jacket (or any other embodiment) can accommodate is greatly increased. When the jacket is in cooling mode, an insulated version of outer air barrier 160 would keep hot air and sunlight from mediating the cooling effect of the device, thereby increasing its efficiency. When the jacked is in warming mode, an insulated version of outer air barrier 160 would more efficiently retain the user's body warmth. Such a warming/cooling jacket can automatically keep a user comfortable year-round in either hot or cold weather. The warming/cooling approaches described in this section would apply just as well to all other embodiments mentioned, such as clothing and accessories for humans, protective garments, embodiments for pets and other animals, blankets and wraps. For example, by simply adding one or more thermostats 140, sensors 141, and control circuits 142, the forced-air blanket embodiment shown in
Reservoir 100, elements 120, inner and outer reservoir barriers 101 and 102, and outer air barrier 160 can appear in a different order than previously shown.
Stabilizing fabric 103 can be an open mesh and can also be partially or completely closed or watertight. If it is an open mesh, or, as in
q shows another option in which reservoir 100 is used both at the tops and the bottoms of elements 120. In this configuration, only one of the two reservoirs would need to be wet by the user because water from one would wet the other by migrating through elements 120. Migration can be speeded by providing one or more wicking materials as bridges between the two layers. Such bridges would have to be intermittent so as not to block air from moving through air space 165.
Although additional layers of fabrics, barriers, or reservoirs can be placed at levels between the tops and the bottoms of elements 120, there would probably be no advantage. Doing so would cause many disadvantages, including:
A concern that must be addressed in all forced air embodiments is the possibility of the formation of mold or mildew between the layers of the device. The fact that outer air barrier 160 restricts airflow to the space surrounding elements 120 is good for maximizing cooling, but also good for trapping moisture inside the device when not in use. For this reason, reservoir 100, outer air barrier 160, and any other layers of the device (including inner reservoir barrier 102 or outer reservoir barrier 101) can be impregnated with a chemical that will suppress the formation or mold or mildew. Additionally, the user can be instructed to remove outer air barrier 160 and/or keep fan 170 on until the device has thoroughly dried before putting it away.
Fan 170 can draw air in from the outside and push it through the device and out the edges, or it can draw air into the device from the edges and out through the fan. However, if the fan is pushing air into the device, it will tend to cause outer air barrier 160 to billow away from elements 120, which might look unappealing. For this reason, configuring the fan(s) to pull air through the device and out through the air is considered a superior solution.
If for any reason fans should need to push air into and through the device, there are several ways to prevent outer air barrier 160 (or any pre-existing outer garment worn over an embodiment designed to accommodate existing garments as described under Expression #3) from billowing away from the device, including the following:
For the device to be most effective, a sufficient volume of air must flow from intake to exit across all of elements 120. Unless the fan or fans are situated in the middle of an area of elements 120 (in most embodiments, this is often impossible or impractical), the device will need one or more permanent edge air barriers 161 to block too much air from entering or exiting any one region of the device at the expense of other regions.
Outer air barrier 160 not only bounds the space around elements 120 to restrict airflow, but visually hides elements 120, providing the possibility of virtually unlimited fashion options. Outer air barrier 160 can be made replaceable, allowing users to buy one base unit and as many outer coverings as suits their needs and desires.
Forced air embodiments can be created for any body part using corrugated elements 126 or deformed elements 127 described under Expression #1 simply by adding at least an outer air barrier 160 and a fan 170 or other means to move air through the resulting spaces.
Expression #3 of my cooling system comprises a group of embodiments in which the function of outer air barrier 160 is fulfilled by an existing article of clothing or piece of gear.
Referring to
c shows an embodiment designed to be used with an existing hat or cap. Fan 170 is on the edge of the device so it won't be blocked by the user's headwear. The user wets reservoir 100, puts on the device, then puts his or her own existing hat or cap 168 over it. When the user turns the device on (battery and switch not shown), fan 170 is activated and begins to circulate air around elements 120, promoting evaporative cooling. Cooling element extensions 123 on the bottoms of elements 120 are not shown.
Embodiments can be created to work with existing articles of protective gear. For example, an existing chemically resistant suit can perform the function of outer air barrier 160 by slipping it over an embodiment of the device designed to provide proper air circulation for that specific suit.
As an example of an article designed for physical protection, a device can be made to accommodate a biker's existing leather jacket. Such a device should not place a fan in any location that would be blocked by the jacket; one or more fans would have to be located at the bottom or top edges of the device, and possibly also at the ends of both sleeves.
From the above descriptions and drawings, it can be seen that my flexible evaporative cooling system clearly improves on prior-art personal cooling systems while simultaneously making possible a whole new range of personal thermal comfort devices. It delivers a powerful, long-lasting cooling effect directly to the skin of a human or animal user, without requiring the user to hold the device or expend any effort. It does not need to wet the user's clothing or skin. It requires little or no battery power to run (none in the fan-free embodiments). It is flexible, and can therefore be worn comfortably on or against a user's body. It can be easily adapted for use on pets and other animals. It can be embodied as clothing, accessories, uniforms, and protective garments. It can be worn under a backpack, motorcycle leathers, or under other garments, uniforms, or protective gear, and it can be used as a sheet, blanket, scarf, or shawl. It can even be embodied as a variety of automated, thermostat-controlled, personal warming/cooling devices.
Some of the many far-reaching ramifications of my cooling system include its ability to:
Many variations on the embodiments described above can be employed within the intended scope of the invention, as elaborated below.
Reservoir 100 can:
Reservoir barriers 101 and 102 can:
External reservoir 109 can:
Additional reservoir(s) 110 can:
Elements 120 can:
Fluid-wicking surfaces 124 of elements 120 can:
Temperature control system (thermostat 140, temperature sensor 141, and control circuit 142) and other electronics can:
Outer air barrier 160 can:
Air space 165 can:
Fan(s) 170 or other air-moving means can:
Fluid delivery means:
Power for electronics and/or air-moving means can be provided by any means, including:
Low water detection and alert systems can include:
The cooling fluid can be varied as follows:
Other variations are possible:
Overall configurations can be varied as follows:
Devices can vary in size, shape, color, and design, and still fall within the intended scope of the invention. The major elements can be put in different positions than shown (e.g., batteries can be located where a water reservoir is depicted, etc.). Thus, the scope of the invention should be determined by the descriptions given above, along with the appended claims and their legal equivalents, rather than by the examples given alone.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2875447 | Goldmerstein | Mar 1959 | A |
| 3125865 | Bemelman | Mar 1964 | A |
| 4451934 | Gioello | Jun 1984 | A |
| 5157788 | Schultz | Oct 1992 | A |
