Underwater thermal protection panel system having dry cores

Abstract

A thermally insulating panel system has a set of panels arranged adjacent to one another. Each panel includes a foamed rubber frame with a cavity. A dry core is positioned within the cavity. Flexible waterproof material seals the dry core within the foamed rubber frame cavity. The panels are joined to each other to form the thermally insulating panel system.

Description

Navy Case No. 212399 UNDERWATER THERMAL PROTECTION PANEL SYSTEM HAVING DRY CORESStatement of Government Interest

[0001] The invention described herein may be manufactured and used by or for the Government of the United States of America for Governmental purposes without payment of any royalties thereon or therefore.TECHNICAL FIELD

[0002] The invention relates generally to thermally insulating systems, and more particularly to a thermally insulating panel system for use in fabricating underwater thermal protection blankets or covers and dive suits.BACKGROUND ART

[0003] When underwater divers or underwater-deployed systems / vehicles must operate in cold water, some type of thermal protection is typically required.Performance requirements for thermal protection increase for long-duration operations taking place in shallow or deep water or for operations that must take place at increased depths. For example, enhanced thermal protection for divers is needed to extend the depth, range, and endurance of diving operations, while also reducing dangerous physiological hazards associated with hypothermia, decompression sickness, and oxygen toxicity. The above hazards are exacerbated when divers use propulsion devices that draw more water across surfaces of their dive suits at a faster pace than swimming thereby causing a more rapid thermal loss and reduction in a diver’s core temperature.Navy Case No. 212399

[0004] The most used material for passive diver thermal protection is foamed rubber (e.g., foamed neoprene). However, foamed rubber is fundamentally flawed in terms of thermal insulation because foamed rubber loses significant thermal resistance as water depth increases. That is, much of foamed rubber’s thermal resistance relies on gas pockets within the flexible rubber material but the gas pockets compress with depth, increasing the density of the material as well as its thermal conductivity. More specifically, studies have shown that a 5 millimeter (mm) thick sample of foamed rubber / neoprene increases in thermal conductivity by up to 42% at depths of 100 feet (30.48 meters). Thermal conductivity continues to increase with increased depth. Furthermore, the increase in thermal conductivity is even greater for thicker foamed rubber / neoprene, e.g., the thermal conductivity of 12 mm thick neoprene increases by 54% at depths of 100 feet (30.48 meters). Thus, the thermal insulation benefit of foamed rubber dive suits at the surface of a body of water is substantially degraded as water depth increases. Further, thermal protection losses increase with water depth when a thicker foamed rubber material is used. This trend is contrary to a diver’s needs since temperature generally drops with depth and dive suit designers tend to use thicker materials when more thermal protection is needed.Summary of the Invention

[0005] Accordingly, it is an object of the present invention to provide a thermally insulating system for use in underwater environments.

[0006] Another object of the present invention is to provide a thermally insulating system that maintains its thermally insulating properties at pressures andNavy Case No. 212399 temperatures encountered throughout an underwater depth profile that will be encountered during an application.

[0007] Still another object of the present invention is to provide an underwater thermally insulating system that is flexible and elastic such that it readily conforms to a human body or other structure such as an underwater vehicle.

[0008] Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.

[0009] In accordance with the present invention, a thermally insulating panel system includes a set of panels where each panel includes a dry core, foamed rubber encircling the dry core, and flexible waterproof material attached to the foamed rubber. The dry core is encased by the foamed rubber and the flexible waterproof material. Each of the panels is joined to at least one adjacent panel from the set of panels.Brief Description of the Drawings

[0010] Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments and to the drawings, wherein corresponding reference characters indicate corresponding parts throughout the several views of the drawings and wherein:

[0011] FIG. 1 is a schematic view of an underwater-thermal-protection panel system having dry cores.

[0012] FIG. 2 is a perspective view of an underwater-thermal-protection panel system having dry cores.

[0013] FIG. 3 is an exploded view of one panel of an underwater-thermal-protection panel system having dry cores.Navy Case No. 212399

[0014] FIG. 4 is an isolated cross-sectional view of a foamed-rubber form taken along line 3-3 in FIG. 3.

[0015] FIG. 5 is a cross-sectional view of the fully assembled panel shown in FIG.3.

[0016] FIG. 6 is an exploded view of one panel of an underwater-thermal-protection panel system having dry cores.

[0017] FIG. 7 is an isolated cross-sectional view of a foamed-rubber frame taken along line 4-4 in FIG. 6.

[0018] FIG. 8 is a cross-sectional view of the fully assembled panel shown in FIG.6.Detailed Description of the Invention

[0019] Referring now to the drawings and more particularly to FIG. 1 , an underwater-thermal-protection panel system in accordance with an embodiment of the present invention is illustrated schematically and is referenced generally by numeral (10). In general, panel system (10) is a flexible material structure that may be configured in size and shape for underwater use. In some embodiments, panel system (10) may be shaped and sized for use in constructing an underwater dive suit. In some embodiments, panel system (10) may be shaped and sized for use in constructing a thermal protection layer for a structure or vehicle that is to be deployed underwater. As will be described further below, panel system (10) is constructed to provide good thermal insulating properties at underwater depths that would greatly reduce the insulating performance of conventional thermal-insulating materials such as foamed rubber.

[0020] Panel system (10) is constructed using a set of at least two panels. In the illustrated example and for purposes of describing the present invention, theNavy Case No. 212399 illustrated portion of panel system (10) has two panels (12) and (14). Panels (12) and (14) may be the same size / shape or different sizes / shapes without departing from the scope of the present invention. In general, each of panels (12) and (14) includes a dry core (20) sealed within an encasement (30). Each of panels (12) and (14) is joined to one or more adjacent panels from panel system (10). For example, in the illustrated embodiment, panels (12) and (14) are joined to one another. More specifically, panels (12) and (14) are joined to one another at a join interface (40) between portions of the panels’ respective encasements (30). Join interface (40) may be created by one or more of gluing, fusing, and stitching. For example, and as shown in the perspective view illustrated in FIG. 2, join interface (40) may include stitches (50) that pass only through adjacent portions of encasements (30) of panels (12) and (14) thereby maintaining the integrity of dry cores (20). In some embodiments, stitches (50) may be made using conventional wet suit stitching materials and technique.

[0021] Dry core (20) may include one or more dry substances having thermal insulation properties that are exhibited if they remain in their dry state. In some embodiments, dry core (20) may be flexible to provide for conformity to the contours of a person or structure. Suitable substances for dry core (20) include gases (e.g., air, nitrogen, argon or other relatively inert gases), void-containing materials (e.g., sections of hard foam, cellular plastics, thermally insulating fabrics, fiber insulation, down feathers, synthetic downs, or any materials that maintain insulating properties under pressure when dry), aerogels, microballoons, open-cell structures (e.g., a contiguous framework of composite open cells, with cell walls made from a polymer material (e.g., thermoplastic polymers, thermoset polymers, etc.) having incompressible materials mixed therein, which may be microballoons or aerogelNavy Case No. 212399 particles of various diameters and / or volume fractions, selected to have low thermal conductivity (e.g., phenolic resin microballoons) in a composite designed to support the stretching and flexing, where misalignment of cell walls breaks up heat transfer paths and enhances the incompressibility attributes of the composite through layers that resist compression forces along the thickness dimension, as described in U.S. Patent Application No. 17 / 970,672, filed October 21, 2022), and combinations thereof.

[0022] Encasement (30) may be constructed from conventional flexible thermally insulating materials that are suitable for use in an underwater environment and are amenable to conventional wet suit construction techniques. Examples for encasement (30) are described in subsequent paragraphs.

[0023] Referring simultaneously now to FIGs. 3-5, an embodiment of a single panel (e.g., panel (12)) of an underwater-thermal-protection panel system is illustrated. In the illustrated example, encasement (30) includes a foamed natural or synthetic rubber (e.g., foamed neoprene) form configured as an open-top container (32) and a flexible and waterproof skin (34). Container (32), a cross-section of which is illustrated in isolation in FIG. 4, may be a monolithic piece of foamed rubber milled or molded to define a cavity (32A) between sides (32B) and a base (32C) that may incorporate a back side of varying depth or placement with respect to proximity to the object to be insulated. Cavity (32A) terminates at the open top (32D) of container (32). Skin (34) is attached and sealed (e.g., glued, fused, etc.) to the open top (32D) of container (32). Suitable materials for skin (34) include, but are not limited to, waterproof rubber, fabrics coated / treated to be waterproof, thermoplastic elastomers, thermoplastic polyurethanes, flexible plastics, etc.Navy Case No. 212399

[0024] In an example illustrated in FIGs. 3-5, dry core (20) is sealed within cavity (32A) as dry core (20) is encircled by sides (32B) and sandwiched between skin (34) and the base (32C) of container (32). When the above-described panel is to be joined to an adjacent panel via stitches (e.g., stitches (50) shown in FIG. 2), such joining stitches only pass through skin (34) and the portion of container (32) that defines its sides (32B) to thereby maintain the dry-state integrity of dry core (20). In some embodiments, seam sealing of the stitching may be applied to waterproof the stitching.

[0025] Another example of encasement (30) is explained with simultaneous reference to FIGs. 6-8. In this example, encasement (30) includes a foamed-rubber form configured as an open-faced frame (33) having its cavity (33A) defined only by the frame’s sides (33B). The resulting opposing open faces (33E) and (33F) of frame (33) serve as the attachment faces for two waterproof flexible skins (34). In this example, dry core (20) is sealed within cavity (33A) as dry core (20) is encircled by sides (33B) and sandwiched between skins (34) as illustrated in FIG. 8. When the panel illustrated in FIG. 8 is to be joined to an adjacent panel via stitching (e.g., stitches (50) as shown in FIG. 2), such joining stitches only pass through skins (34) and the portion of frame (33) that define its sides (33B) to thereby maintain the drystate integrity of dry core (20). In some embodiments, seam sealing of the stitching may be applied to waterproof the stitching.

[0026] The advantages of the present invention are numerous. The panel system described herein allows for use of conventional thermally insulating materials in a novel structure having a reduced thermal loss as compared to conventional foamed rubber at both shallow and deep underwater depths. The described panel system may be used to construct large thermally insulating sheets or to construct complexNavy Case No. 212399 contour-conforming shapes for use as diver hoods, dive suits, etc. The panel system maintains the dry core material(s) in their dry state required for thermal protection performance. When used to construct a dive suit, the panel system may be readily configured for stretchability to provide comfort as well as the good fit required for thermal protection performance. The panel system provides an underwater thermal protection solution that is less bulky and more comfortable than conventional alternatives. The dry water-impermeable cavity created within the described panel system may be filled with a variety of dry-performing materials that provide better thermal resistance and compression resistance than typical materials. The cavity may include or be filled with custom gas mixes to further maximize thermal protection. The panel system’s encasement is readily adapted for conventional joining techniques (e.g., seaming, stitching, gluing, fusing, sealing, etc.) that will not penetrate or compromise the dry-core-containing cavity. It is anticipated that joining adjacent panels by fusing adjacent portions of the waterproof material may be practical. Likewise, adjacent panels can be joined by gluing adjacent natural rubber frames.

[0027] There are numerous variations and modifications for combining components including: dry cores (20) of different types or materials; diverse panel (12, 14) types or configurations; encasement (30) or frame (33) shapes or materials; and waterproof material (34) type or thickness that will be readily apparent to those skilled in the art for improving performance for scenarios dictating specific durability, flexibility, mass, or depth requirements. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described.

Claims

Navy Case No. 212399 ClaimsWhat is claimed is:

1. A thermally insulating panel system (10) for providing compression-compensating thermal protection in an underwater environment, comprising:a plurality of panels (12, 14) arranged adjacent to one another, characterized in that each panel further comprises:an encasement (30) defining a cavity (32A, 33A);a dry core (20) positioned within the encasement (30) cavity (32A, 33A); flexible waterproof material (34) sealed to the encasement (30) to seal the dry core (20) within the encasement (30) cavity (32A, 33A); and wherein the plurality of panels (12, 14) are each joined to at least one adjacent panel (12, 14) from the plurality of panels (12, 14).

2. The thermally insulating panel system (10) of claim 1, wherein the encasement (30) is a foamed rubber frame (32, 33) and the dry core (20) is made from a material selected from the group consisting of a gas, a void-containing material, a contiguous framework of open cells, a composite having microballoons, an aerogel, and combinations thereof.

3. The thermally insulating panel system (10) of claims 1 or 2, wherein the panels (12, 14) are each joined to at least one adjacent panel (12, 14) by stitches (50) passing only through the flexible waterproof material (34) and the encasement (30) of the panel (12) and adjacent panel (14).

4. The thermally insulating panel system (10) of claim 1, wherein:Navy Case No. 212399 the encasement (30) is a foamed rubber frame (33) that has a first side (33E) and a second side (33F), and the foamed rubber frame cavity (33A) allows communication between the first side and the second side;the dry core (20) is positioned in the foamed rubber frame cavity (33A); andthe flexible waterproof material (34) comprises two pieces of the flexible waterproof material (34) with a first piece (34A) being sealed to the foamed rubber frame first side (33E) and a second piece (34B) being sealed to the foamed rubber frame second side (33F).

5. The thermally insulating panel system (10) of claim 1, wherein:the encasement (30) is a foamed rubber frame (33) that has, in a normal orientation facing the flexible waterproof material (34), a front side (32D) and a back side (32C), the front side (32D) being open and allowing communication with the foamed rubber frame cavity (32A), and the back side (32C) being sealed;the dry core (20) is positioned in the foamed rubber frame cavity (32A); andthe flexible waterproof material (34) is sealed to the foamed rubber frame (32) front side (32D).

6. The thermally insulating panel system (10) of claim 1 , wherein the encasement (30) is a foamed rubber frame (32) that is a container (32) having a base (32C) and sides (32B), the foamed rubber frame (32) cavity (32A) being defined by the base and sides wherein the sides terminate at an open end (32D) of the container (32),Navy Case No. 212399 and wherein the flexible waterproof material (34) is attached to the container (32) at the open end (32D).

7. A thermally insulating panel system (10) for providing compression-compensating thermal protection in an underwater environment, comprising:a set of panels (12, 14) positioned adjacent to one another, characterized in that each one of the set of panels (12, 14) further comprises:an encasement (30) defining a cavity (32A, 33A);a thermally insulating core (20) disposed in the cavity (32A);a flexible waterproof material (34) attached to the encasement (30), wherein the thermally insulating core is encased by a combination of the encasement (30)and the flexible waterproof material (34); andwherein each one of the set of panels (12, 14) is joined to at least one adjacent panel (12, 14) from the set of panels (12, 14).

8. The thermally insulating panel system (10) of claim 7, wherein the encasement (30) is a foamed rubber form (32, 33) and the thermally insulating core (20) is made from a material selected from the group consisting of a gas, a void-containing material, a contiguous framework of open cells, a composite having microballoons, an aerogel, and combinations thereof.

9. The thermally insulating panel system (10) of claims 7 or 8, wherein each panel of the set of panels (12, 14) is joined to at least one adjacent panel by stitches (50) passing only through the flexible waterproof material (34) and the encasement (30).Navy Case No. 212399 10. The thermally insulating panel system (10) of claims 7 or 8, wherein each panel of the set of panels (12, 14) is joined to at least one adjacent panel (12, 14) by fusing adjacent portions of flexible waterproof material (34) associated with one panel (12, 14) with flexible waterproof material (34) associated with another adjacent panel (12, 14).

11. The thermally insulating panel system (10) of claims 7 or 8, wherein each panel of the set of panels (12, 14) is joined to at least one adjacent panel (12, 14) by gluing adjacent portions of the encasement (30) associated with one panel (12, 14) with the encasement (30) of another panel (12, 14).

12. A thermally insulating panel (12, 14) for use in an underwater compressioncompensating thermal protection system, the thermally insulating panel (12, 14) comprising:a foamed rubber frame (32, 33) defining a cavity (32A, 33A), characterized in that the thermally insulating panel (12, 14) further comprises:a dry core (20) positioned within the foamed rubber frame cavity; andflexible waterproof material (34) sealed to the foamed rubber frame (32, 33) to seal the dry core (20) within the foamed rubber frame (32, 33) cavity (32A, 33A).

13. The thermally insulating panel (12, 14) of claim 12 wherein:the foamed rubber frame (33) has a first side (33E) and a second side (33F), and the foamed rubber frame cavity (33A) allows communicationNavy Case No. 212399 between the first side and the second side;the dry core (20) is positioned in the foamed rubber frame cavity (33A);the dry core (20) is positioned in the foamed rubber frame cavity (33A);the flexible waterproof material comprises two pieces of the flexible waterproof material (34) with one piece being sealed to the foamed rubber frame first side (33E) and the second piece being sealed to the foamed rubber frame second side (33F).

14. The thermally insulating panel (12, 14) of claim 12 wherein:the foamed rubber frame (32) has a front side (32D) and a back side (32C), the front side being open and allowing communication with the foamed rubber frame cavity (32A), and the back side being sealed;the dry core (20) is positioned in the foamed rubber frame (32) cavity (32A);andthe flexible waterproof material (34) is sealed to the foamed rubber frame (32) front side (32D).

15. The thermally insulating panel (12, 14) of claim 12, wherein the foamed rubber frame is a container (32) having a base (32C) and sides (32B), the foamed rubber frame (32) cavity (32A) being defined by the base and sides wherein the sides terminate at an open end (32D) of the container, and wherein the flexible waterproof material (34) is attached to the container at the open end.

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