Classifications

• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47C—CHAIRS; SOFAS; BEDS
  • A47C7/00—Parts, details, or accessories of chairs or stools
  • A47C7/62—Accessories for chairs
  • A47C7/72—Adaptations for incorporating lamps, radio sets, bars, telephones, ventilation, heating or cooling arrangements or the like
  • A47C7/74—Adaptations for incorporating lamps, radio sets, bars, telephones, ventilation, heating or cooling arrangements or the like for ventilation, heating or cooling
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47C—CHAIRS; SOFAS; BEDS
  • A47C21/00—Attachments for beds, e.g. sheet holders, bed-cover holders; Ventilating, cooling or heating means in connection with bedsteads or mattresses
  • A47C21/04—Devices for ventilating, cooling or heating
  • A47C21/042—Devices for ventilating, cooling or heating for ventilating or cooling
  • A47C21/046—Devices for ventilating, cooling or heating for ventilating or cooling without active means, e.g. with openings or heat conductors
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47C—CHAIRS; SOFAS; BEDS
  • A47C27/00—Spring, stuffed or fluid mattresses or cushions specially adapted for chairs, beds or sofas
  • A47C27/002—Mattress or cushion tickings or covers
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47G—HOUSEHOLD OR TABLE EQUIPMENT
  • A47G9/00—Bed-covers; Counterpanes; Travelling rugs; Sleeping rugs; Sleeping bags; Pillows
  • A47G9/10—Pillows
  • A47G9/1036—Pillows with cooling or heating means
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
  • A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
  • A61G5/10—Parts, details or accessories
  • A61G5/1043—Cushions specially adapted for wheelchairs
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
  • A61G7/00—Beds specially adapted for nursing; Devices for lifting patients or disabled persons
  • A61G7/05—Parts, details or accessories of beds
  • A61G7/057—Arrangements for preventing bed-sores or for supporting patients with burns, e.g. mattresses specially adapted therefor
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
  • A61G7/00—Beds specially adapted for nursing; Devices for lifting patients or disabled persons
  • A61G7/05—Parts, details or accessories of beds
  • A61G7/057—Arrangements for preventing bed-sores or for supporting patients with burns, e.g. mattresses specially adapted therefor
  • A61G7/05707—Arrangements for preventing bed-sores or for supporting patients with burns, e.g. mattresses specially adapted therefor with integral, body-bearing projections or protuberances
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
  • A61G7/00—Beds specially adapted for nursing; Devices for lifting patients or disabled persons
  • A61G7/05—Parts, details or accessories of beds
  • A61G7/057—Arrangements for preventing bed-sores or for supporting patients with burns, e.g. mattresses specially adapted therefor
  • A61G7/05784—Arrangements for preventing bed-sores or for supporting patients with burns, e.g. mattresses specially adapted therefor with ventilating means, e.g. mattress or cushion with ventilating holes or ventilators
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F7/00—Heating or cooling appliances for medical or therapeutic treatment of the human body
  • A61F7/10—Cooling bags, e.g. ice-bags
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
  • A61G2210/00—Devices for specific treatment or diagnosis
  • A61G2210/70—Devices for specific treatment or diagnosis for cooling

Definitions

• the present invention relates to support surfaces that remove heat from human or other mammalians.
• the normal core temperature of the human body is between 36° and 38°C. Skin temperature typically ranges between about 30°C and about 34°C, depending on ambient temperature, the amount and type of clothing being worn, the core temperature, and where the skin is located on the body.
• tissue metabolic rates increase by approximately 10 % for each one degree Celsius increase in temperature. Warmed tissue generates an increased demand for blood supply that can be met when the skin is not under significant load. At interface pressures of 20 or more mm Hg, as occur under the bony prominences on a mattress or seat, blood flow can not be increased to meet this demand and the tissue becomes ischemic.
• a study demonstrated that skin tissue with reduced blood supply has been shown to be less susceptible to injury when tissue temperatures were slightly reduced.
• Temporary skin cooling can be accomplished by increasing the heat input required to increase the temperature of the surface.
• the quantity of heat required to increase the temperature of a given quantity of material by a specific temperature is called the specific heat.
• the specific heat can be expressed in Joules/kg-degree K.
• the quantity of heat required to raise the temperature of a given body is referred to as the heat capacity of the body. If a large sample and a small sample are both made of the same material, for example, the larger sample will have a greater heat capacity although both will have the same specific heat.
• a surface composed of high specific heat material such as silicone gel or fluid, or even a waterbed, will provide temporary cooling because a great deal of the body's heat will flow from the skin, initially at approximately 30 to 34° C to the surface, initially at 23° C room temperature. The skin will continue to be cooled as long as the surface remains cooler than the skin. Materials with low specific heat, such as a urethane foam, warm rapidly toward body temperature and therefore cool the skin only very briefly. [0010] In order to provide continuous, steady-state cooling, heat is removed and transferred to the environment or to another system that is external to the surface to be cooled. A need exists for non-powered, or, stated otherwise, self-powered, relatively inexpensive devices to provide steady state cooling at the level of the expensive, externally powered LAL surfaces currently in use.
• the skin is cooled passively by conduction (not convection) without external power.
• Heat is transferred from the body via a highly thermally conductive layer or layers of material(s) (referred to in this specification as the Conducting Component) that are soft, pliable, and comfortable to sit or lie on.
• the layer is connected with conductive materials that are configured to transport heat and diffuse the heat to a cooler environment.
• the heat wick may be positioned within a powered surface to enhance cooling.
• the device may be embedded in, on placed upon, a surface in which the power drives a stream of air that convectively cools the region adjacent to the patient and the patient..
• the heat wick may be configured to efficiently draw heat from region adjacent to the patient into the stream of moving air. The air-stream enhances heat withdrawal from the diffuser region.
• Figure 1 is a perspective view of a mattress with one embodiment of the cooling surface shown in the central position of the mattress 16.
• Figure 2 is a sectioned view of a mattress according to one embodiment of the invention.
• Figure 2A is a sectioned view of a mattress according to another embodiment of the invention.
• Figure 3 is a perspective view of a mattress according to an additional embodiment of the invention.
• Figures 4 and 5 are sectioned views of mattresses according to additional embodiments of the invention.
• Figure 5A is an exploded view of a mattress according to an additional embodiment of the invention.
• Figure 5B is a sectioned view of the mattress as shown in Figure 5A.
• Figure 6 is a perspective view of a bed comprising an embodiment of the invention.
• Figure 6A is a perspective view of a bed comprising an embodiment of the invention.
• Figure 7A is a perspective view of a bed comprising an embodiment of the invention.
• Figure 7 is a perspective view of a multi-cellular mattress, seat cushions, or seat backs.
• Figure 8 is a perspective view of a multi-cellular seat cushions.
• Figure 9 is a perspective view of a multi-cellular seat backs.
• Figure 10A is a perspective view of a duvet comprising an embodiment of the invention.
• Figure 10B is a perspective view of a bed cover comprising an embodiment of the invention.
• These conductive materials may be pitch-based carbon fibers or polymers with thermal conductivities in excess of 40 W/m-K.
• the predominant orientation is across the mattress (i.e., perpendicular to the long axis of the mattress), they have a zig-zag or somewhat sinusoidal or wavy configuration.
• This geometry allows the support region 2 to stretch in the predominant fiber direction (in this case, perpendicular to the long axis of the mattress) without imposing undue stress on the conductive materials (i.e., the fibers or polymers) themselves.
• This geometry provides structural support to the conductive materials that is not afforded when the fibers run strictly transverse to the mattress without zig-zag or wavy motions.
• the conductive fibers, polymers, or nanotubules may be chopped to the length of each zig-zag. At each corner the overlap between fiber bundles should be substantial (greater than or equal to 2 mm) to ensure continuity of the heat conduction path.
• the conductive material is preferred to be encased in a thin envelope or attached to a layer 4 of protective sheeting (such as urethane) or fabric (such as Lycra).
• the envelope may be a closed or an open sheath, like a duvet cover that provides protection and can be laundered, allowing the conductive material to avoid the harsh cleaning process.
• a stretchy material is preferred because it provides additional protection to the conductive materials.
• small slits 5 may be provided that allow for distension of the envelope or sheet when a load is placed upon it.
• the conductive elements of the support region 2 overlap with those of the thermal diffuser region 6. This region receives heat that is transported conductively from the support region that is adjacent to the body.
• the same highly conductive material as the support region may be used so that heat is rapidly distributed over a relatively broad, but cooler, area and diffused into the still cooler environment.
• the diffuser region is peripheral to the support region and may present at the edges or sides of the seat or mattress, or underneath, or suspended slightly to the side of the surface.
• the Conducting Component is not a simple one-dimensional "pipe,” and it may have complex geometries that enable it to perform its heat transfer function efficiently for a given application.
• Another embodiment is shown in Figure 3.
• Conductive material 3 in the support region 2 is formed in a wavy configuration.
• the fibers are continuous with, but not overlapping, the fibers in the diffuser region 6.
• This continuity of fibers between support and diffuser regions is shown in Figure 4.
• the fiber direction changes as the fibers reach the edge of the support region, and have a different orientation in the diffuser region.
• the continuity, or discontinuity, of fibers between these regions may be used with either the wavy or the zig-zag configurations. This configuration may not require that every single fiber is continuous across the surface.
• the cooling surface is shown in use as a mattress overlay on top of the mattress ticking 1. It may be used beneath the ticking, as shown in Figures 1 and 2, and may be used either beneath, or on top of, a seat cushion or seat cover.
• the diffuser region 6 may be at the edge or sides of the bed, and may extend underneath the mattress or seat cushion. For a seat back embodiment, the diffuser region extends to the reverse side of the seat back.
• the support and diffuser regions overlap with one another 7 and are oriented so that they most efficiently direct heat from warmer regions to cooler regions. A right angle intersection may allow for conduction of heat from the body outwardly, and then to direct the heat along the edges of the bed or other support.
• FIG. 5B is an end-view of the conduction device in use with a mattress and a mattress overlay.
• the diffusers hang vertically from the edge of the bed and are not under the mattress.
• the device is on top of the ticking.
• Various embodiments may be positioned inside or outside the mattress with similar effectiveness. Because the diffuser positions are not clamped between the mattress and the bed frame, when the user puts his/her weight on the support region and compresses the center portion of the device, and the edge diffuser regions are free to draw inward to accommodate this compression. Because the stress on the loaded conductive fibers 3 is much less with the diffusers 6 untucked, the fibers may not be wavy or zig-zagged.
• Figure 6A depicts another embodiment. Parallel fibers, or more generally, conductive materials 3, extend from the support region 2. The device is presented as a long rectangle, or double arrow-shape, if the diffuser is longer in the center.
• the device is an H shape, in which the cross segment of the H is the support region that runs across the bed, and the vertical segments of the H represent the diffuser regions.
• the two ends of the rectangle (or arrow) form the diffuser regions 6. They may be positioned underneath the mattress 16, or they may hang along the sides of the bed.
• the device is effectively a long "heat wick" made up of generally parallel conductive materials 3 that are shaped like a long scarf, and may be positioned at any point in the bed or seating surface to draw heat away from the selected anatomic site.
• the diffusers may extend along the edge of the mattress, or they may be positioned under the mattress, or they may hang freely at the side of the bed, as shown in Figures 6 and 6A.
• the diffuser region is preferred to be located at the periphery of the region to be cooled, and maintained at a distance from it.
• the diffuser region may be located on the vertical edges of the mattress or seat, and it may wrap to the underside of the mattress or seat, or around to the seat back for seat back cooling.
• the support region 2 and the diffuser regions 6 are in thermal contact. They may be continuous, as shown in Figure 3 in which the conductive material bundles simply change direction in the diffuser regions to aid in the distribution of heat over a broader area in these cool regions of the surface. Alternatively, they aere continuous, but do not change direction, as in the long scarf-shaped heat wick configuration described above ( Figure 6A).
• Figures 5 and 6 depict embodiments that are appropriate for use with multi-cellular mattresses, seat cushions, or seat backs.
• a variety of quality support surfaces employ an array of relatively small air, foam, gel, or elastomer cells 8 that project toward the user and comfortably conform under weight loading. Because these surfaces sometimes overly warm the skin, a conductive cooling device may be integrated into the surface or used in conjunction with it.
• the strips can be bound together loosely using a small amount of elastic thread from strip to strip.
• the device is incorporated into a cooling seat and seat back.
• Conductive strips 9 run between the cells 8 and draw heat to the cooler diffuser regions at the periphery 10 and 11.
• the conductive strips may be separated 10, or overlap a conductive sheet at the periphery, to enhance cooling area 11.
• the multi-strip configuration may be placed on top of the surface, or the strips may be embedded in the surface between the cells.
• Reference number 14 identifies the base cushion or base seat back which is present in the existing seat to prevent bottoming.
• Reference number 15 identifies the periphery of the seat, which may be constructed of a firmer foam or elastomer to add seating stability.
• the seating surface may comprise conductive material or be overlaid with conductive material 3 to aid in thermal diffusion to the environment.
• the conductive material 9 is built into a base cushion 14 that runs beneath and between the cells 12. This base cushion may also form a rim at the periphery to add stability.
• the conductive elements 3 in the conductive layer 12 extend to the edge that surrounds the multi-cellular region and forms the diffuser region at the edge of the surface.
• the conductive layer may wrap into a lip at the outer edge of the seat cushion or to the rear of the seat back to increase the surface area exposed to ambient conditions for heat dumping to the environment.
• the next series of figures demonstrate placement of the device over the user rather than underneath.
• the cooling blanket of Figure 10A is shown as a duvet insert.
• FIGs 11 A and 11B are cross-sectional views of two possible embodiment of the embedded device.
• the diffuser regions 6 reach through the ticking and extend through the frame toward the floor. This is a particularly efficient configuration for cooling.
• Figure 11 B the diffusers wrap under the mattress and are inside the ticking.
• Figures 12, 13 and 14 depict the device with surfaces that use power to drive a stream of coolant, which may be air, through the mattress. Such surfaces may be referred to as "low air-loss surfaces”.
• the wick 23 is positioned in the region of the powered mattress 24 that supports the region of the body to be cooled, which, as shown, is the central region of the torso and hips.
• a control box for the mattress that contains the pump or blower unit 25 is present. Air is transported from the box to the mattress through air hose 26, and enters a small manifold 30 along the foot end of the mattress.
• An air hose oriented transversely to the mattress may be used as a manifold. Air escapes from air vents 28, and streams of air blow through the mattress to carry heat away from the heat wick, particularly in the diffuser region. As a result of this enhanced heat removal from the diffuser region, the temperature gradient between the support region and the diffuser region is increased, thus enhancing cooling.
• Figure 13 is a top view of the wick 23 in use with a slightly different type of low air-loss surface 24.
• the air stream is vented directly from the support cushions through small holes 29. These vents may be positioned directly under or adjacent to the Heat Wick and once again, function to draw heat away from the wick and into the air stream from which it is expelled from the mattress.
• Figure 14 is a perspective view of a wick 23 in use with a mattress 24 similar in construction to that depicted in Figure 13 with the air stream directed through the mattress via air vents 29 in a hose or manifold 30.
• Figure 14 shows the diffuser regions 6 of the heat wick which, as previously discussed, may be positioned in a number of configurations to exhaust heat.
• Cooling mattresses and mattress inserts, cushions and seat back inserts, overlays, tickings, and bedding materials such as blankets and duvet inserts may be configured to absorb heat from a user's skin and transport this heat to a cooler environment.
• the non-powered wick can enhance cooling of both non-powered surfaces, such as foam, or powered surfaces that cool the body with moving air, such as low air-loss surfaces.
• Various materials with high levels of thermal conductivity and mechanical compliance may be configured within a specific range of geometries to cool the skin in a highly effective and cost-effective manner.
• the support region may be positioned under the user, for example, as a seat cushion, mattress, or mattress overlay, or against the user, for example, as a seat back, or over the user, for example, as a blanket or a duvet cover.
• the heat wick itself is preferred to have no moving parts and no external source of power, relying on geometric configurations of conductive materials to cool the skin.
• the Conductive Component in the heat wick has high thermal conductivity, is relatively compliant, and therefore comfortable to use. The device should not have excessive levels of electrical conductivity or flammability that may endanger the user.
• the Conducting Component has sufficiently high directional thermal conductance to accommodate heat transfer along its length as required by the specific application.
• the Conducting Component absorbs, transports, and dumps heat.
• the Conducting Component runs throughout the device, but functions to absorb heat from the skin in the warm support region, and diffuse it to the environment in the cooler diffuser region.
• the Conducting Component serves a transport function in moving heat from one region to the other.
• the Conducting Component is essentially a heat conduit or series of conduits that is absorbs heat at one end (the support region), transports it to another end (the diffuser) where it releases heat to the environment.
• the Conducting Component may be consist of sheets, strips, fibers, or yarns formed of highly conductive materials (typically highly conductive carbon fibers, nanotublules or polymers), or comprised of such materials interleafed or otherwise combined with insulation or cushioning materials.
• the Conducting Component may be a layer within the heat wick cooling device that comprises layers to enhance durability, cushioning, or otherwise enhance usability.
• the mean conductivity of the Conducting Component between top surface of the conductive layer and the bottom surface of the conductive layer is greater than or equal to 8 W/m-K.
• the top of this layer is defined as the surface closest to the skin of conductive material (defined as greater than or equal to 8 W/m-K).
• the bottom of this layer is the surface of the Conducting Component that is farthest from the skin, with this layer being having thermal conductivity greater than or equal to 8 W/m-K.
• this entire Conducting Component which may be comprised of several layers of varying thermal conductivities, has a mean conductivity of greater than or equal to 8 W/m-K in the direction of preferred heat transfer.
• the surface of Conductive Component closest is preferred to be within 3 inches (7.5 cm) of the body. That is, this Conducting Component may extend to several inches depth but the edge closest to the body is within 3.0 inches of the body when in use. The closest edge of the Conducting Component is within 3.0 inches of the skin whether it is on top of the body (i.e., a blanket) or below it and compressed by the weight of the human body (a cushion or mattress) or pressed against it (a seat back).
• a blanket i.e., a blanket
• the fibers or bundles of conductive elements are preferred to be oriented to draw heat away from the body and toward a cooler diffuser region.
• the conductive elements are generally parallel to the surface of the skin in the support region but there may be a relatively small number of bundles in the support region that have a component that is perpendicular to the skin to enhance the flow of heat from the skin to the deeper regions of the conductive layer.
• Some fiber bundles may be oriented with a component that is perpendicular to the primary direction of heat conduction described above. When present, they are oriented such that a component is perpendicular to the surface.
• the Conducting Element may be enclosed in an envelope of material such as urethane film, or may be enclosed in, or attached to a cloth material, particularly a stretchy cloth such as Lycra.
• the Conducting Element may or may not be embedded in or adjacent to additional cushioning material such as batting, gel, foam, or elastomer.
• the conductive elements may be laid between surface layers with no binding or carrier agent, or they may be bound with an adhesive material, to stabilize the fiber positioning and add additional strength with a binding material.
• Other suitable binding agents include spray urethane, and other glues that maintain conformability when dry.
• the fibers may be incorporated into the ticking or seat cover, glued or sewed to the underside of the ticking or seat cover, glued or sewed on the mattress underneath the ticking, or interleafed with layer or layers of the ticking as by lamination process.
• the conductive layer may be incorporated in to the mattress or cushion materials such as foam in a single or multiple layer, interleafing configuration.
• the Conducting Component is compliant in the support regions so that it deforms significantly under the weight of the body.
• a 1.0 kg steel ball placed in the center of the support region of the intact surface i.e. the surface of a mattress, seat cushion etc. with the cooling device in place
• a 1.0 kg steel ball placed in the center of the support region should cause the surface of the Conducting Component to compress by greater than or equal to 0.25 mm.
• There should be sufficient mechanical compliance to the conductive layer so that it is not stiff and uncomfortable to the user.
• the conductive material required to achieve preferred heat conductivity and transport sufficient heat to cool according to the application of interest may be quantified.
• the numbers represent the mean directional thermal conductivity k (in Watts per meter degree Kelvin or W/m-K) and the total thickness T in m of the Conducting Component. The two values are specified together because there is an inverse relationship between the mean thermal conductivity k of the material used in the Conductive Component and the thickness of the layer required to conduct sufficient heat to cool the skin under the set of thermal conditions present in the applications of interest here.
• Table 1 reflects constraints on the conductivity (k) of the material used in the transport layer and the thickness of this layer (T), such that k x T is greater than or equal to 0.006 W/K, and less than or equal to 12 W/K.
• k x T in the range of 0.05 to 6 W/K are optimal, because a number of applications for this cooling technology have been proposed, a broad range of k x T has been specified to accommodate the various types of geometries that are possible.
• • k x T greater than or equal to 0.006 and less than or equal to 12 W/K is the overall range of interest specified
• • k x T greater than or equal to 0.02 and less than or equal to 10 W/K is the preferred range of interest specified
• • k x T greater than or equal to 0.05 and less than or equal to 6 W/K is the highly preferred range of interest specified 10.
• the conductive layer is not continuous when viewed from a point not in the plane of the surface.
• the layer may be separated into parallel strips or bundles of conductive material when viewed from a point perpendicular to the surface such as above a mattress or in front of a seat back.
• the conductive material is positioned between the air cells that may form a grid or run perpendicular to the body. In such cases, the k x T requirement applies to the mean thickness of conductive material across the region to be cooled, including these separations between bundles.
• the conductive layers may be positioned only in the central region of the bed or seat to cool the buttocks and / or low back, and may be positioned at any location on the bed, seat, or seat back surface to cool different regions of the body or, in some cases, may be positioned to cool the entire body.
• the conductive elements may be distributed across the entire seat cushion and seat back.
• Conductive materials can now be purchased in a variety of thermal conductivity levels and the selection of the appropriate material is based on cost, mechanical characteristics, electrical characteristics (high electrical conductivity is undesirable for a support material in the hospital environment), etc.
• the table below gives additional specificity as to the quantity of thermally conductive material required. [0081] The Table contains only the first range listed in #9 above. This is the Overall Range of interest. We have also specified a Preferred Range (B.) and a Highly Preferred Range (C.)
• This fiber orientation is preferred because conductivity is typically oriented disproportionately along the axis of the fibers or wire.
• the filaments normally lie parallel to the surface of the mattress or seat and conduct heat away from the body.
• a small number of highly conductive fiber bundles oriented perpendicular to the surface in the primary region of cooling in the center of the mattress or seat may be used.
• All configurations of conductive layers, fibers, or fiber bundles may be used inside the ticking, or outside the ticking, as a mattress or seating overlay.
• thermal diffuser regions are equivalent in function to that of a radiator in a typical heat transfer application.
• the thermal diffuser is underneath a ticking and bedding, the bulk of the heat sinking from the diffuser is done not by radiation but conduction to the surface of the mattress ticking and bedding materials. Heat is released from this outer surface to the environment primarily by radiation and convection.
• the term "thermal diffuser" is used, because it transports heat from the support surface to the environment by any of the possible modes of heat transfer, and not only by radiation.
• the thermal diffuser regions may be positioned at the distal regions of the support surface or blanket, away from the region to be cooled, such that heat conducted from the warm central region flows to this cooler diffuser area.
• the diffuser(s) may be along the top surface of the bed or seat, along the periphery, and/or it may extend to the sides of the surface, such as the edges of the bed or seat. Another preferred position is for the diffuser regions to simply hang down below the bed or seat for exposure to the cool air under the bed or chair. They may also extend to the opposite side of the support surface, such that they extend underneath the bed, underneath a seat, or around to the back side of a seat back.
• the thermal diffuser regions may be thermally connected to the thermal conduction layer of the support surface.
• the thermal diffuser material may be very similar to, if not identical to that of the conductive layer in the support region.
• the diffuser is the region of the conductive layer that extends substantially away from the support region to increase the heat exhaustion area.
• the thermal diffuser is constructed of material with high thermal conductivity (greater than or equal to 8 W/m-K).
• the thermal diffuser may comprise conductive cloth, strips, sheets, foils, louvers or fibers, yarn, or fabric woven of conductive material.
• the diffuser may, in some applications, be enclosed in or attached to a protective covering.
• the thickness of the Conductive Element in the diffuser area conforms to a k x T criterion (see Table 1) of k x T > 0.001 W/K and ⁇ 10 W/K.
• the surface area of the thermal diffuser may be variable, depending on the application because the amount of heat to be exhausted, and the heat transfer conditions from the diffuser surface. In general, however, the surface area is at least 0.25 times as great as the area of the body that is being cooled. Under typical heat transfer conditions, the diffuser area is 1.5 to 5.0 times the area of the region of the body to be cooled. In less favorable environments or when more cooling is required, the area may be 10 or more
• the capabilities are specified to an extent by the k x T parameter
• A Area of slab perpendicular to the direction of heat flow in square meters (m 2 )
• L length of slab in direction of long axis of body. In other words, this is the length of the body to be cooled (m)
• X Length of conduction path in meters. In the figure below, this is the distance from the hot face to the cold face of the slab in meters (m).
• Hot - ⁇ cold Temperature difference between hot and cold faces of slab in degrees K (K).
• the specified quantity k x T can be used to calculate the amount of heat per unit length of the body that can be withdrawn under a set of environmental constraints.
• a ⁇ and X are constraints that are set by the application: A ⁇ is the temperature difference between the support and the diffuser regions and X is the distance between them.
• the k x T parameter therefore is an attempt to quantify a range of constraints on the thickness and conductivity of the Conducting Element to ensure that the device can perform the skin cooling function in the expected range of environments (i.e., thermal and geometric) in which it performs.
• the described devices of the present inventions may be utilized as a therapeutic support surface, such as a mattress, mattress overlay, a wheel chair cushion, seat cushion or seat back or seat overlay for home, office, or vehicle applications.
• support region region of the support surface (mattress, mattress overlay, seat cushion or seat back) intended to be close to, adjacent to or in contact with the body 3.
• conductive material typically high thermal conductivity carbon fibers, polymers or nanotubules
• thin envelope or layer of protective sheeting such as urethane) or fabric (such as Lycra) that encases conductive material
• slits which may or may not be added o the envelope or protective sheet material to enhance the distension of the surface to accommodate weight loading.
• thermal diffuser region the cooler region at the edge of the support surface to which the body's heat is transported. From the thermal diffuser, it is transported to the cooler environment by air flowing past it or conduction to adjacent materials 2.
• Mattress overlay that may or may not be used with conductive device, which is placed on top of mattress and ticking in this configuration 9. base cushion at bottom of seat cushion or rear of seat back to prevent bottoming out 10.
• Periphery of seat which may include conductive material at edge to form thermal diffuse 11.
• standard mattress that conductive cooling device can be placed on top of, placed inside of, or built into.
• cooling insert that can be placed in duvet (blanket cover) of a cooling blanket 13.
• blanket cover or duvet that cooling blanket can be slipped inside to enhance comfort and provide protection 14.
• structural sheet or blanket to which cooling elements can be attached 15. support region of cooling blanket 16.diffuser region of cooling blanket 17.
• thermally conductive strips that may or may not be covered for protection 18.
• Powered air surface to which non-powered wick has been added to enhance cooling 20 Control box for air surface with blower 21.Air hose that takes air from control / blower box to powered air surface to which non-powered wick has been added or built into 22. Air bladders of air surface 23. Air vents from which air is blown into the mattress and ultimately across the non-powered wick to enhance cooling. 24. Vents in cushions of low-air loss air surface that blow air onto the non- powered wick to enhance cooling. 25. Manifold from which air vents into mattress

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• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Nursing (AREA)
• Otolaryngology (AREA)
• Pulmonology (AREA)
• Mattresses And Other Support Structures For Chairs And Beds (AREA)
• Thermotherapy And Cooling Therapy Devices (AREA)

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• 2005
  • 2005-06-02 WO PCT/US2005/019413 patent/WO2006001980A2/en active Application Filing
  • 2005-06-02 EP EP05793951A patent/EP1768627A4/de not_active Withdrawn

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