SYSTEMS AND METHODS OF PASSIVE BODY TEMPERATURE MANAGEMENT

Abstract

A cooling blanket, including a wall defining a body portion, a plurality of elongated chambers positioned within the body portion, a plurality of baffles positioned within each respective elongated chamber, at least one respective port operationally connected to each respective elongated chamber, and cooling fluid positioned within each respective elongated chamber. The respective elongated chambers are respectively sized to restrict fluid flow towards the ends.

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application claims priority to co-pending U.S. Provisional Patent Application Ser. No. 63/134317, filed Jan. 6, 2021.

BACKGROUND

The average adult human body emits over 100 watts of latent heat. Blankets are used to regulate personal body temperature by increasing the resistance to thermal diffusion across a barrier. As heat accumulates the local body temperature increases. Passive heating blankets, such as down comforters and wool blankets, as well as active heating blankets, such as electric blankets and electric heating pads, are known in the art. These devices regulate a user's body temperature by concentrating the thermal energy produced by the user, and in the case of active blankets, adding thermal energy to the consumer through the use of resistive electrical elements. While blankets are efficient at increasing body temperature, few options exist for decreasing body temperature.

Conventional strategies for decreasing body temperatures rely on decreasing the temperature of the entire ambient environment, often through air conditioning or open ventilation with the environment. This method is highly energy inefficient where the ambient temperature of an entire room or even house is adjusted for the sake of personal cooling. In addition, environmental changes may adversely affect the comfort levels of other individuals resting in the ambient environment.

Previous attempts to make a cooling pads or blankets have relied on open circuit actively recirculating systems where a fluid filled pad or blanket is continuously flushed with fresh fluid provided by a fluid reservoir and pump. While these systems are effective, they are not suitable for passive cooling applications. They also need to periodically change the fluid in the fluid reservoir once the fluid temperature approaches body temperatures. As a result, these systems typically only provide transient benefits of up to a few hours.

Other attempts to make cooling blankets have focused on thermal absorption through the use of high heat capacity acrylate gels; however, these systems are also only effective for a short period of time lose their effectiveness once the gel approximates body temperature. While the high viscosity acrylate polymers enable relatively even distribution across the blanket, the high viscosity also limits thermal conductivity and cooling rates. In addition, polymer filled blankets must be shipped as a prefilled structure due to the sealed design and hazardous nature of poly-acrylate gels, or the like. As a result, previous attempts to utilize polymer gel filled chamber to impart cooling have achieved limited success.

Thus, there is a need for a more efficient means for decreasing personal body temperature regulation without the need for adjusting the ambient environment. The present invention addresses this need.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1. is a diagrammatic representation of a horizontal cross section of a first embodiment of the present invention.

FIG. 2. is a perspective view the embodiment of FIG. 1.

FIG. 3. is a diagrammatic view of a first weld patter according to a second embodiment of the present invention.

FIG. 4. is a diagrammatic view of a second weld patter according to a second embodiment of the present invention.

FIG. 5. is a diagrammatic view of a third weld patter according to a second embodiment of the present invention.

FIG. 6. is a diagrammatic view of a fourth weld patter according to a second embodiment of the present invention.

FIG. 7 schematically illustrates introducing a fluid having surfactants and active cooling agents through a port into a cooling blanket of FIG. 1.

DETAILED DESCRIPTION

Before the present methods, implementations, and systems are disclosed and described, it is to be understood that this invention is not limited to specific synthetic methods, specific components, implementation, or to particular compositions, and as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting.

As used in the specification and the claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed in ways including from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another implementation may include from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, for example by use of the antecedent “about,” it will be understood that the particular value forms another implementation. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. Similarly, “typical” or “typically” means that the subsequently described event or circumstance often though may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

A cooling blanket 10 according to one embodiment of the present disclosure comprises a body 35 with an internal, fluidically isolated volume defined by the blanket wall 20. The body 35 may form a bulk volume 25, a series of channels 30 mechanically fixed to a predetermined orientation, or a series of isolated chambers 15 mechanically fixed to a flexible structure (such as the wall 20). The body 35 and/or respective chambers 15 may further include baffles 40 to regulate the movement of fluids 45 between channels 30 within the chamber 15. The cooling blanket 10 may also include a cooling fluid 45 (typically a cooling liquid), at least one access port 50 to enable fluidic communication between the body 35 and/or the respective chambers 15 and the external environment. The cooling fluid 45 may contain wetting agents or surfactants 65 and/or active cooling agents 70. The cooling blanket 10 may also contain ventilation channels 85, fasteners 90, and /or covers 75.

Cooling blankets 10 may be constructed of a single layer 55 material where the chamber wall 20 also defines the external contact surface, or multiple layers 55, where a non-permeable layer is protected by an external fabric or material, such as nylon reinforced polyethylene, wherein a polyethylene material defines the non-permeable internal boundary of the chamber 15, and the nylon provide mechanical support and abrasion resistance to environmental surfaces during normal use. Layers 55 may be formed utilizing molding processes such as blow-molding of plastic preforms, or heat-sealing of multiple layers together to form internal hollow cavities. While blow-molded structures are capable of producing seamless structures that are molded to access ports, they are typically costly at low volumes due to the mold expense. Hot sealed structures are preferred for low volume and multilayer construction. Hot seal seams 60 are typically formed by heating one or more layers 55 to the plastic softening point thereby forming a multi-layer union. The seams 60 are typically 3 mm to 6 mm wide and form a flat seal that surrounds the chamber walls 20 and defines the edge of the chamber volume. A three-dimension chamber 15 may then be formed by filling the chamber 15 with a fluid 45 through the access port 50.

A chamber 15 may be formed by a flexible, non-permeable material such as vinyl, polypropylene, mylar, polyester, polyethylene, such as high-density polyethylene (HDPE) or low-density polyethylene (LDPE), or nylon reinforced polyethylene, or the like. Multiple layers 55 may be pre-bonded together, as in the case of nylon reinforced polyethylene or polyurethane reinforced polyethylene, to form a single film prior to sealing. To layer of multilayer film may then be layered such that their non-permeable surfaces are facing one another, and sealed using conventional techniques. Non-permeable surfaces may further be modified by wetting agents or surface modifiers 65 (such as by conventional surfactants, such as alkoxylate surfactants, silicone surfactants, polysiloxanes, sulfosuccinates, polyacrylates, fluorinated polyacrylates, or star shaped polymers) so as to prefer to remain in certain predetermined portions of the body 35. A multilayer structure may also contain one or more metalized layers 55 (such as aluminized polyester or aluminized mylar) or metal foil layers 55 (such as aluminum or copper foil) to further enhance thermal transmission and reflect infrared radiation. In some embodiments, a metalized or metal foil layer 55 is only used on one side of a multi-layer, hot sealed cooling blanket 10 intended to enhance thermal transmission away from the user.

An access port 50 may be constructed of an open portion of the chamber 15 left exposed during initial construction, and used to fill with a fluid 45 prior to permanently sealing, or may be made of a separate mechanical structure such as a fill tube 50, which may be sealed permanently through conventional techniques or temporarily through a pinch valve or like technology, a check valve, a screw cap, or any combination thereof. The access port 50 may be used to fill the blanket 10 prior to packaging and be permanently sealed, or sealed by the end user.

A fluid 45 may fill or partially fill a chamber 15 to further enhance thermal communication across the cooling blanket 10. The fluid 45 is preferably a low viscosity fluid with typical viscosity of less than 1,000 Centipoise (CP), more typically less than 500 CP, still more typically less than 100 CP, yet more typically less than 50 CP, and still more typically less than 15 CP. In one embodiment, the chamber 15 may be filled with water, such as deionized water or tap water. A wetting agent or surfactant 65 as previously described may be added to the fluid 45 to improve thermal communication or applied to the chamber walls 20 prior to filling with a working fluid 45. The fluid 45 may enter the chamber through access port 50. The volume of fluid 45 typically added to a chamber 15 is less than the maximum chamber volume, and more typically less than 50 percent of the maximum volume, and still more typically less than 35 percent of the maximum chamber volume. Air is typically removed from the chamber 15 prior to filling and residual air is typically removed once the chamber 15 is sufficiently filled. The residual air forms a head space in the chamber 15, which is typically less than 10 percent of total chamber volume, more typically less than 2 percent of total chamber volume, and still more typically less than 1 percent of total chamber volume.

In some embodiments, the fluid 45 includes an active cooling agent 70. The active cooling agent 70 enhances cooling across the chamber 15 by undergoing a temperature dependent physical change across the chamber 15. The active cooling agent 70 may be a miscible volatile chemical, such as isopropanol, butanol, or the like, selectively soluble volatile compound, such as butane, a salt with a temperature dependent solubility, such as calcium chloride, potassium nitrate, ammonium nitrate, silver nitrate, cesium sulfate, sodium nitrate, potassium chlorate, or the like, or a magnetically active fluid, such as a ferrofluid. The active cooling agent 70 may be added to the fluid 45, such as water, such that it forms an undersaturated, saturated, or supersaturated solution, depending on the anticipated environmental conditions. In some embodiments a super saturated salt solution may precipitate or form concentrated solutions on a first surface and dissolve or form more dilute solutions on a second surface, such that thermal transmission is enhanced across chamber volume.

The cover 75 may be a cleanable fabrics or film, such as cotton, bamboo cloth, polyesters, percale, sateen, or flannel, expanded polytetrafluoroethylene (PTFE), or the like. The cover 75 may be solid, woven, knit, formed, spun, or the like. The cover 75 may be water permeable or non-permeable, textured or smooth. The cover 75 may further include fasteners 90, such as buttons, hook and loop connectors, zippers, or the like for mechanically adhering the cover 75 to the cooling blanket 10.

The chamber 15 may form a channel 30 that may be defined as a geometrically restricted structure within the larger cooling blanket 10. Channels 30 define the fluid path within the chamber 15 and may be used to resist the tendency for a fluid to selectively migrate away from the user during operation. Typically channels 30 represent tubular structures, that may be between 25 mm and 100 mm wide prior to filling with a fluid 45, and may traverse the length of the blanket 10. Channels 30 may form interdigitated structures or may weave back and forth across the blanket 10. Channels 30 are generally formed longitudinally along the length of the blanket 10 such that they are positioned from head to toe during use. Channels 30 may vary in width along their path, which may be typical with a longitudinal of 50 mm to 100 mm connected by to a parallel channel 30 via a side channel 30 of 10 mm to 50 mm. Channels 30 are typically narrower towards their oppositely disposed ends.

One or more baffles 40 may be used to regulate and/or retard fluidic communication between one or more channels 30 within a chamber 15. A baffle 40 may include flaps formed by additional film or fabric, semipermeable plugs, such as nitrocellulose or polyester fabrics, or valves, such as check valves formed by weights, balls, needle valves, access ports, or the like. Baffles 40 may also be formed by capillary channels of less than 25 mm wide.

The cooling blanket 10 may also contain non-movable weights 95 made of a dense material, such as lead, tin, aluminum, or iron, that may be bound into the blanket structure to provide greater mechanical stability by providing a constant force on the user during fluidic shifts, which may help to keep the blanket stationary as the user tosses and turns throughout the night.

Air-filled bladders 80 may be added to the blanket 10 and maintained fluidically isolated from fluid filled channels 30 to enhance mechanical rigidity along the air-filled bladder 80. Air bladders 80 may also be used to decrease or modulate the relative cooling efficacy along the blanket 10 and allow for greater comfort. In one embodiment, air bladders 80 are positioned within the blanket 10 in thermal communication with the user's arms and legs to prevent over-cooling of the user's extremities.

A ventilation hole 85 may be formed by removing excess film formed beyond the hot seal seam 60 during manufacturing; these holes 85 enable direct ambient communication across the sides of the cooling blanket 10 to prevent body moisture accumulation and suffocation during use. In some embodiments, ventilation holes 85 may be small (for example 3 mm to 10 mm across their longest axis) or large (for example 100 mm to 500 mm across their longest axis).

In another embodiment, the body 35 may form a bulk volume 25, further including a series of point welds 100 mechanically fixed to either side of the body 35, thereby constricting the body's 35 volumetric expansion. The welds 100 may be solid or rings with hollow centers. The rings may be sonically welded. They may be 5 to 25 mm in diameter, and for hollow rings, may have a weld thickness of at least 5 mm, more typically at least 8 mm, more typically at least 10 mm thick. The chamber 15 may be constructed of poly urethane of at least 60 durometer, more typically at least 70 durometer, and still more typically 80 durometer. Welds 100 of the present embodiment may form an array ranging between 25 to 250 mm apart. The weld pattern 105 may be more constricted on the sides of the blanket 10 resulting in hydrostatic pressure to urge fluids 45 toward predetermined portions of the body portion 35 of the blanket 10, typically such so as to keep the fluid 45 elevated above the user. Typically, a low viscosity fluid will drain to the sides of the individual, thereby decreasing cooling efficiency and capacity. By restricting the volumetric expansion of the chamber 15, a hydrostatic pressure is produced due to the elasticity of the chamber walls 20, resulting in fluid elevation and fluid concentration at higher elevations. Examples of weld patterns may be found in FIGS. 3-6.

In other embodiment, each respective individual chamber 15 may have welds 100 operationally connected thereto to restrict expansion.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination may in some cases be excised from the combination, and the claimed combination may be directed to nigh-infinite subcombinations or variations of a subcombination.

Claims

1. A cooling blanket, comprising:

a wall defining a body portion;

a plurality of elongated chambers positioned within the body portion;

a plurality of baffles positioned within each respective elongated chamber;

at least one respective port operationally connected to each respective elongated chamber; and

cooling fluid positioned within each respective elongated chamber;

wherein the respective elongated chambers are respectively sized to restrict fluid flow towards the ends.

2. The cooling blanket of claim 1 and further comprising a plurality of fasteners connected to the body portion and a cover connected to the fasteners.

3. The cooling blanket of claim 1 wherein the fluid further comprises one of the group consisting of surfactants, wetting agents, active cooling agents, and combinations thereof.

4. The cooling blanket of claim 1 wherein the wall is a multilayer material.

5. The cooling blanket of claim 4 wherein the multilayer material includes a metallized layer for reflecting infrared radiation away from the blanket.

6. The cooling blanket of claim 1 and further comprising at least one air bladder positioned within the body portion.

7. The cooling blanket of claim 6 wherein respective air bladders are positioned within respective elongated chambers.

8. The cooling blanket of claim 1 wherein the wall is at least partially coated with a wetting agent.

9. The cooling blanket of claim 8 wherein the wall is selectively coated with the wetting agent to encourage the fluid to prefer predetermined portions of the body portion.

10. The cooling blanket of claim 1 and further comprising a plurality of welds operationally connected to the body portion and positioned to restrict volumetric expansion of the body portion to generate hydrostatic pressure to urge fluid to predetermined portions of the body portion.

11. A thermal reduction blanket, comprising:

a flexible body portion separating an interior volume from an exterior environment;

a plurality of welds formed on the flexible body portion for restricting volumetric expansion of the interior volume;

a liquid at least partially filling the interior volume;

a plurality of baffles positioned withing the interior volume; and

a wetting agent at least partially covering the flexible body portion in the interior volume;

wherein the plurality of welds and the wetting agent establish a hydrostatic pressure to urge the liquid toward predetermined portions of the flexible body portion.

12. The thermal reduction blanket of claim 11 wherein the plurality of welds are oriented to define a predetermined pattern.

13. The thermal reduction blanket of claim 11 and further comprising weights disposed within the interior volume.

14. The thermal reduction blanket of claim 11 and further comprising a plurality of air bladders positioned within the interior volume.

15. The thermal reduction blanket of claim 11 and further comprising a plurality of channels disposed within the interior volume.

16. The thermal reduction blanket of claim 11 and further comprising a plurality of ventilation passages formed through the thermal reduction blanket.