PROCESS FOR THERMOREGULATING A FLEXIBLE CELLULAR MATERIAL BY COMPRESSION AND EXPANSION OF THE GAS TRAPPED IN ITS CELLS AND ASSOCIATED DEVICE

Abstract

A flexible cellular material is thermoregulated by compressing and expanding gas trapped in its cells A flexible elastomer material of a device that provide thermoregulation includes two layers of different shore hardness and conductivity and is has gas-filled cells. Each cell has a zone to store the gas when compressing the material in the layer C with higher hardness and thermal conductivity and another zone to expand the gas when decompressing the material in the layer D with lower hardness and thermal conductivity. The flexible material can be used as a sole in shoes to maintain a cool temperature. With each step, the cell zones located in the layer C act as adiabatic chambers whose gasses heat with compression. When the foot leaves the ground the zones of cells located in the layer D then act as a reactor nozzle that will expand the air and therefore cool it.

Claims

1. A device for thermoregulation comprising a flexible and elastic material, having sealed cells filled with air or with gas, each cell having two interconnected zones, including: a first zone storing the gas during the compression of said flexible material, and a second zone for expanding the same gas during the decompression of said flexible material.

2. The device according to claim 1, wherein: said material is formed in two layers, including: a first layer with a higher hardness in which are arranged the first zones of the cells for storing gas during the compression of the material, and a second layer with a lower hardness in which are arranged the second zones of the cells for expanding the same gas during the decompression of the material.

3. The device according to claim 1, wherein: said material is formed in two layers, including: a first layer with a higher thermal conductivity in which are arranged the first zones of the cells for storing gas during the compression of the material, and a second layer with a lower thermal conductivity in which are arranged the second zones of the cells for expanding the same gas during the decompression of the material.

4. The device according to claim 2, wherein the flexible and elastic material is used inside a shoe as a sole, the second layer being positioned on a foot side of the sole and the first layer being positioned on a bottom side of the sole to keep a foot cool despite a warm ground.

5. The device according to claim 2, wherein the flexible and elastic material is used inside a shoe as a sole, the first layer being positioned on a foot side of the sole and the second layer being positioned on a bottom side of the sole to keep a foot warm despite a cold ground.

6. The device according to claim 1, wherein the flexible and elastic material is used as a floor mat in an establishment open to the public or in a business with foot traffic so that foot pressure points provide thermoregulation.

7. The device according to claim 2, wherein: the first layer has a higher thermal conductivity, and the second layer has a lower thermal conductivity.

8. The device according to claim 7, wherein the flexible and elastic material is used inside a shoe as a sole, the second layer being positioned on a foot side of the sole and the first layer being positioned on a bottom side of the sole to keep a foot cool despite a warm ground.

9. The device according to claim 7, wherein the flexible and elastic material is used inside a shoe as a sole, the first layer being positioned on a foot side of the sole and the second layer being positioned on a bottom side of the sole to keep a foot warm despite a cold ground.

10. The device according to claim 3, wherein the flexible and elastic material is used inside a shoe as a sole, the second layer being positioned on a foot side of the sole and the first layer being positioned on a bottom side of the sole to keep a foot cool despite a warm ground.

11. The device according to claim 3, wherein the flexible and elastic material is used inside a shoe as a sole, the first layer being positioned on a foot side of the sole and the second layer being positioned on a bottom side of the sole to keep a foot warm despite a cold ground.

12. The device according to claim 2, wherein the flexible and elastic material is used as a floor mat in an establishment open to the public or in a business with foot traffic so that foot pressure points provide thermoregulation.

13. The device according to claim 3, wherein the flexible and elastic material is used as a floor mat in an establishment open to the public or in a business with foot traffic so that foot pressure points provide thermoregulation.

Description

[0012] FIGS. 1 to 3 show the device intended in sections, for example, to be placed as a sole in shoes with the layer D in contact with the foot.

[0013] in FIG. 1, the cellular flexible material is at rest and the gas is uniformly distributed in the cells at the temperature T.sub.a and pressure P.sub.a. A distinction is made between the two layers C and D and the respective zones C and D of the cells.

[0014] in FIG. 2, pressure is applied to the flexible material and since layer D has a lower hardness than layer C, layer C will be less compressed. However, gas located in the D zones of the cells will be pushed into the C zones of the cells. Then, the gas will be compressed at the pressure P.sub.i (depending on the pressure exerted, i.e., about 2 bars for a person weighing 70 kg) and will therefore heat up to the temperature T.sub.i according to the laws of thermodynamics.

[0015] The temperature T.sub.i of the gas will thus be equal to:

T.sub.a×(P.sub.i/P.sub.a).sup.(γ−1)/γ

where γ is the adiabatic constant of the gas (approximately 1.4 for air at 293° K.) and about 376° K. if T.sub.a is 293° K. Since layer C has a greater thermal conductivity, the heat of the gas will then dissipate more easily through this layer to reach the temperature T.sub.f of about 365° K. for a thermal conductivity λ of the layer C de 1 W/m/° K.

[0016] FIG. 3 shows the material once the pressure is released (when the foot leaves the ground). The gas, pressurized, at the temperature T.sub.f, will leave the zones C to expand in the zones D and thus cool down to the temperature:

T=T.sub.f×(P.sub.a/P.sub.i).sup.(γ−1)/γ

or about 285° K., a temperature 8° K. lower than the initial temperature T.sub.a. Thanks to the low heat exchange operated by the D layer, this temperature difference will be maintained thanks to the repeated steps cycles and despite the losses inherent to the materials and to the absorption of the runner's foot.

[0017] In another arrangement, the flexible material may be used as a heating method. It suffices for this to invert the sole and therefore it is the layer C which is in contact with the foot. Thus, the heat generated during the compression will be in contact with the foot while the cold zone will be in contact with the bottom of the shoe.

[0018] The gas contained in the cells may simply be air, but it is advantageous to use gases with a higher adiabatic constant γ such as a monoatomic gas (Ar for example) in order to obtain a higher yield.