Heat exchange – Heat transmitter
Reexamination Certificate
2001-04-24
2004-03-02
Bennett, Henry (Department: 3743)
Heat exchange
Heat transmitter
C165S907000, C165S902000, C165S046000, C165S010000, C165S010000, C002S002120, C002S002150
Reexamination Certificate
active
06698510
ABSTRACT:
FIELD OF INVENTION
The present invention relates to the field of temperature regulation devices and, more particularly, to a material containing gel particles that is useful for regulating fluid flow in response to changes in temperature such as the flow of water in a wet suit to control skin temperature of the wearer and to methods for regulating temperature using the same.
BACKGROUND OF THE INVENTION
Exposure suits can be classified into two general categories, wet and dry. Traditional wet suits are usually manufactured of porous neoprene. They allow water to impregnate the suit material, trapping a thin layer of water between the fabric of the suit and the wearer's skin, which is warmed by body heat. Essentially, wet suits rely on limiting the amount of water exchange between the inner surface of the suit and the environment to keep the wearer warm and, for this reason, suit fit is of critical importance. Generally, the degree of protection against the outside environment increases with fabric thickness. Although wet suits are efficient in protection against cold water, they are constricting because they have a tight fit and tend to inhibit free movement due to their thickness. Small punctures will not have a major impact on the functionality of the suit.
Dry suits, on the other hand, are manufactured of impermeable materials, normally have latex rubber seals at the extremities, and are filled with air. The trapped air provides an insulating effect in the suit, but thermal underwear must also be worn for protection against the cold. Although these suits allow ease of movement, they are not practical for swimming, because the buoyancy and displacement effects of the air hamper body control. If punctured, dry suits can take on significant amounts of water, rendering them useless in terms of insulation and dangerous in terms of flotation.
Survival and thermal exposure suits for ice water conditions tend to be of the dry suit type. These suits offer excellent protection by keeping the wearer dry and warm through a combination of the insulating properties of air and the use of underclothing. They are ideally suited to survival conditions because they provide a high level of buoyancy and the highest degree of thermal protection against cold conditions. They are, however, susceptible to leakage and punctures.
Once punctured and saturated with water, dry suits retain roughly 35% of their insulating capability. This asymptotic trend is attributed to the fact that once the suit is saturated, additional water simply fills the space between the suit and the body. At this point the only thermal protection is that offered by the waterlogged suit material. Based on the function of a wet suit, it can be argued that, should the dry suit not limit water exchange once punctured, the remaining insulation capability would drop further.
Tests have been conducted on individuals performing various activities in cold water while wearing wetsuits having different thicknesses. (See Wolff, A. H., Coleshaw, S. R. K., Newstead, C. G., Keatinge, W. R., 1985 “Heat Exchanges in Wet Suits,”
Journal of Applied Physiology
, vol. 58, no. 3, pp 770-777). It was reported that the flow of water between the suit and the skin was responsible for a significant portion of the heat loss in the suit. Typically, up to 30% of the heat loss at rest and up to 60% during exercise was reported to be caused by the forced convection resulting from water being pumped between the skin and the suit.
Consequently, it was reported that, for good insulation, fabric thickness is not as important as the limiting of water exchange under the suit. Wolff et al., reported that the difference in protection offered by a 4 mm and a 7 mm fabric is not radically different once the flow of water is restricted.
Even minor movement drastically increases the flow of water under the suit. The flow at the torso was reported to be roughly double that at the limbs, which can be attributed to the higher degree of suit fit accuracy on the limbs. In all cases, the test subjects were able easily to regulate and stabilize their body temperature for a large range of environmental conditions by controlling the flow through their movement. In cases where they overheated, simple movements would allow them to cool down by increasing water flow.
Various attempts at controlling the temperature of a diver have been made in the prior art. U.S. Pat. Nos. 3,367,319; 3,391,686; 3,402,708; 3,402,709; 3,450,127; 3,566,205; 3,572,314; 3,583,386; 3,884,216; 4,167,932 and 4,294,225 all disclose devices and methods for supplying heated fluid to a diver's suit. Some of those methods rely on exothermic chemical reactions that result from the mixture of two substances. Others rely on the transfer of heat from combustion of fuel to water circulated within the diving suit. All of these devices require a power source, usually strapped to the back of the diver, which will function for a definite time before requiring replenishment. U.S. Pat. No. 3,430,688 discloses a garment that comprises a mesh of tubes in which a fluid is circulated to provide cooling to the wearer. U.S. Pat. No. 5,960,469 describes an undergarment to be used by divers with wet or dry suits. The undergarment has a number of bladders filled with an insulating fluid, which has very low thermal conductivity. Fluid from an external reservoir is pumped into the bladders to provide the desired level of insulation.
All of the aforementioned patents disclose attempts at regulating the temperature in garments for use in extreme environmental conditions, but none address the issue of how to control the temperature and flow of water due to pumping under the wet suit.
U.S. Pat. No. 5,722,482 to Buckley describes a fabric containing a material for use in the manufacture of wetsuits, where the material regulates skin temperature. This apparatus regulates heat transfer through the action of a phase change material, embedded in one or more layers of the fabric. The phase change material stores or provides latent heat energy through its transition between the solid and liquid states. The method seeks to control conductive heat transfer through the wetsuit fabric. Due to the nature of the phase change materials, the suit is effective only until the phase change of the available material is complete, after which the phase change material must be regenerated.
U.S. Pat. No. 5,277,915 to Provonchee et al. describes a gel-in-matrix composition containing a fractured hydrogel that was formed in a foam matrix. The gel is treated to form a network of fractured channels to create hydraulic permeability to allow aqueous media to flow freely through the gel-in-matrix for efficient, intimate contact of the gel with a liquid medium. There is no teaching or suggestion that liquid flow through the gel-in-matrix can be controlled by changes in temperature.
U.S. Pat. No. 5,447,689 discloses a method and apparatus for flow control that consists of sizing materials applied to a porous substrate, such as foam. These materials are able to hold a fluid for a discrete time and then release it, effectively delaying its flow, but they have no capability to regulate flow in response to prevailing environmental conditions such as, for example, a change in temperature.
The latent heat of phase change between liquid and gas has been widely used in the control of heat flux. That takes advantage of the substantially large amount of heat energy that can be stored as latent heat during phase changes. U.S. Pat. No. 5,955,188 to Pushaw discloses a foam substrate that is impregnated with a dispersion of microspheres having such a phase change material encapsulated therein and the method for producing it. The phase change disclosed in Pushaw is associated with latent heat energy for melting a solid material such as a paraffin and, thus, must be regenerated (solidified).
None of the prior art provides a method or a material for controlling fluid flow in a layer containing gel particles in response to changes in temperature.
SUMMARY OF THE INVENTION
The p
Bromberg Lev
Masters Brett P.
Serra Marco
van Reenen Pretorius Jaco
Bennett Henry
Edwards & Angell LLP
Jensen Steven M.
Mide Technology Corporation
Neuner George W.
LandOfFree
Article and method for temperature regulation using a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Article and method for temperature regulation using a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Article and method for temperature regulation using a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3248144