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Gas distribution garmentRelated Patent Categories: Apparel, Guard Or ProtectorGas distribution garment description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060026743, Gas distribution garment. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] The present invention relates to a personal gas distribution garment, preferably a ventilated cooling garment. One embodiment is directed to a ventilated cooling garment for use by a wearer who is clad in a sealed overall suit and breathing system which is designed to protect the wearer from harmful chemical, biological or other environmental hazards. It is also a function of the ventilated cooling garment of the present invention that it may be adapted to use filtered ambient air as the ventilating cooling medium. Further desirable attributes of the garment are high cooling power, low weight, low bulk, good flexibility, and high water vapour permeability, all of which contribute to the comfort of the wearer. BACKGROUND OF THE INVENTION [0002] It is well known that subjecting a person to prolonged periods of inadequate heat dissipation leads to an increase in body temperature (heat stress), indicated by undesirable effects such as discomfort, increased fatigue, decreased physical and intellectual performance and, in extreme cases, death. Body core temperatures in excess of 38.degree. C. will, for example, lead to impaired decision making and increased reaction times whereas core temperatures in excess of 40.degree. C. can cause physiological damage and fatalities. Increased body temperature can result from accumulation of heat from external sources, metabolic processes due to exertion, or a combination of both. Personnel such as fire-crews, "hazmat" operatives such as those working on toxic or generally hazardous cleanup operations, and chemical plant operatives handling hazardous products are potential victims of such heat stress. Such personnel have usually to wear virtually totally sealed garments which severely inhibit cooling effects that would naturally occur due to ambient air flow over the persons skin and clothing. [0003] One possible measure to prevent the onset of heat-stress is to blow a cooling gas, usually air, optionally cooled, over the subject's body, which results in cooling of the subject by a combination of convective and evaporative cooling. Studies of heat stress effects have shown that, to minimise such effects, the average desirable amount of cooling supplied to a subject undergoing moderate exertion is a minimum of 100 watts over the area of the torso. (Ref.:"Techniques for Estimating Ventilation Requirements for Personal Air-cooling Systems", J. W. Kaufman, Naval Air Warfare Center report NAWCADPAX-99-92-TR.) [0004] Various approaches have been proposed to achieve "air-cooling" of subjects. For example, a system disclosed in U.S. Pat. No. 5,243,706 to Frim et al. is one such approach. The construction of the garment disclosed in this reference comprises an air-impermeable layer and an air distribution layer attached together with a corrugated mesh spacer layer in between. A further mesh spacer layer is positioned between the air-permeable layer and the body of the wearer. Cooling air is fed into the space between the air-permeable and air-impermeable layers, exits the air permeable layer, and is distributed over the body of the wearer. Given the multi-layer construction of the garment and the inclusion of the corrugated spacer layer the flexibility, fit and comfort of the garment would be severely compromised and would be unlikely to meet the desirability criteria defined supra. Also, the relatively high resistance of the mesh fabrics to the flow of air necessitates a high pressure air source not readily available in a portable (or non-tethered) system. [0005] U.S. Pat. No. 5,564,124 to Elsherif et al. discloses a personal ventilation apparatus which comprises a garment incorporating areas of air permeable material, such as open cell foam, to direct air to selected areas of the body. The system also comprises a battery powered blower unit which, optionally, includes thermoelectric heating or cooling devices or filters. Given the small areas over which the cooling air is vented relative to the total area of the torso, the cooling power of the garment disclosed in this reference is likely to be severely limited and not meet the cooling criteria previously defined. [0006] U.S. Pat. No. 5,970,519 to Weber discloses a cooling garment for medical personnel which comprises a simple two ply construction of an air impermeable layer and an air permeable layer, each having minimal thickness, defining a cavity into which air is blown. The cavity has no spacers, or intermediate material or structures except in the shoulder regions to prevent the collapse of the garment in that area when the garment is worn under a heavy apron such as a radiological shield. One distinct shortcoming of such a system is the absence of any intermediate layer to control airflow within the cavity resulting in uneven air distribution. A further shortcoming is the lack of a means for controlling air distribution between the inner air permeable layer and the body of the wearer. The absence of such mechanisms may cause excessive cooling of some areas of the wearer's body, especially next to the air inlet port, while not supplying sufficient cooling in other areas. It is an objective of the present invention to overcome the shortcomings of the systems described above. SUMMARY OF THE INVENTION [0007] The present invention is directed to a gas distribution garment system which can be used with sealed garments such as are used in hazardous or toxic environments, as well as in other applications where the subject is exposed to high heat stress situations such as fire-fighters, clean room operatives or hospital theatre operatives. In a preferred embodiment, a gas distribution cooling garment system most conveniently comprises a vest which delivers cooling air only to the torso, but may also be a jacket with sleeves, a coverall with sleeves and legs, or any other form which delivers cooling air to specific areas of the body. For optimum comfort and cooling efficiency it is desirable that the garment conforms closely to the body shape of the wearer. [0008] It is an object of the present invention that the cooling gas can be ambient air and that the air can be filtered to remove undesirable components from the cooling air. The cooling gas may also be passed through a heat exchanger to lower the temperature of the gas or through a de-humidifier to further increase its cooling capability. Furthermore, it has been determined that the most efficient cooling using air at an ambient temperature of about 35.degree. C. is achieved by having an air flow of about 4 to 8 liters/second (l/s) over the subject and that the flow should be confined to layer no more than about 4 mm from the body of the subject. [0009] Another object of the invention is to provide a high degree of cooling to the wearer, in addition to natural cooling experienced by the wearer, for an extended period of time. Preferably, more than 50 watts of additional cooling is provided over the torso for a period of at least about three hours; more preferably greater than about 80 watts of additional cooling, and further preferred greater than about 100 watts of additional cooling is provided over the torso of a wearer for a period of at least about three hours. [0010] Yet a further object of the invention is that by the use of a gas distribution manifold and a plurality of discrete elements within the cavity defined by the substrates comprising the invention, substantially uniform cooling is achieved over the torso of the wearer. [0011] It is a further object of the invention to provide a personal cooling system that is "non-tethered" and is light-weight. In a preferred embodiment the total weight of the system is less than 3 kilograms. [0012] A further object of the invention is to provide a cooling garment which comprises substrates having high water-vapour-permeability thereby minimising the build-up of perspiration on the wearer's body even when the garment is not supplied with cooling gas. [0013] One embodiment comprising the gas distribution garment of the present invention comprises a first and a second substrate sealed to define at least one cavity. The first substrate is substantially gas-impermeable but water-vapour-permeable. The second substrate is gas-permeable and preferably water-vapour-permeable. The surface of one or both substrates which is orientated towards the inside of the cavity are provided with a plurality of raised protrusions in the form of discrete elements, and the cavity is adapted to contain a gas distribution manifold which is in fluid connection with a gas supply system. The surface of the second substrate external to the cavity is also provided with a plurality of raised protrusions in the form of discrete elements. [0014] In one preferred embodiment, the garment is in the form of a vest, and in use the second substrate will form the inside of the vest such that gas exiting the cavity through the gas-permeable second substrate will flow over the torso of the wearer. The plurality of discrete elements on the surface of the second substrate external to the cavity provides a space between the substrate and either the body of the wearer or any other garment worn thereon. The height of the discrete elements are chosen such that the space between the wearer's body, or any other clothing worn next to the wearer's body, and the gas permeable second substrate is sufficiently wide to allow uniform flow of cooling gas but not so wide that it reduces the cooling effect of the gas. The in-plane spacing between the discrete elements is optimised to distribute the flow of gas exiting the cavity and give substantially uniform cooling of the torso. [0015] The plurality of discrete elements on one or both surfaces of the substrates within the cavity provides a space between the surfaces thereby allowing optimal distribution of the cooling gas within the cavity, and therefore across the wearer's body. [0016] In another embodiment, a gas distribution garment system comprises protrusions external to the cavity that are disposed on an additional substrate that is interposed between the body of the wearer and the external surface of the second substrate forming the cavity. The interposing substrate is preferably water-vapour-permeable and may be gas-permeable. The interposing layer may be attached to the substrates forming the cavity or detached from the cavity substrates. [0017] The plurality of discrete elements contributes to increased conformability of the garment of the present invention by allowing flexing between protrusions compared with prior art garments which utilise mesh or mesh-like spacers. The flexibility of substrates suitable for use in the present invention, having a pattern or plurality of discrete elements thereon, is not substantially less than the flexibility of substrates without any discrete elements. In contrast, the three dimensional structures of the mesh or mesh-like spacers of the prior art lack flex points and they are generally bulky and stiff; therefore the use of these structures results in garments having poor flexibility and conformability. [0018] Furthermore, the plurality of discrete elements also result in a garment construction having lower resistance to gas flow compared with garments of the prior art that utilise mesh or mesh like materials as spacers. Mesh spacers are constructed with material that can interfere with the air flow, whereas materials of the present invention have no intervening material between the discrete elements to interfere with air flow. The low resistance to gas flow afforded by the discrete elements facilitates the use of low power fans to supply cooling gas to the invention and obviates the need for the garment to be "tethered" to a power supply or a high pressure supply of cooling gas. Thus, a preferred embodiment comprises a "portable" or "non-tethered" gas distribution garment system which, as used herein, refers to a system which is not tethered to a (stationary) power supply or a high pressure gas supply. The cooling gas may be ambient air blown into the cavity by battery powered fans which may be optionally fitted with filter elements or other gas treatment systems to remove noxious or other undesirable contaminating components. DESCRIPTION OF THE DRAWINGS [0019] FIG. 1 represents an embodiment of the invention in the form of a vest and comprising a fan as a means to drive ambient air through a manifold into the cavity of the garment. [0020] FIG. 2 is plan view of the body side of the vest illustrating the relative disposition of the discrete elements on the substrate and perforations in the said substrate. Continue reading about Gas distribution garment... Full patent description for Gas distribution garment Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Gas distribution garment patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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