Phase change thermal-sink apparatus
10295268 ยท 2019-05-21
Assignee
Inventors
Cpc classification
F25D3/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25D2303/0845
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D15/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25D2303/082
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25D2303/0831
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F28F7/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D15/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
Cartridges for maintaining objects at a desired temperature for extended periods of time can be constructed by sealing a thermoconductive cover on a flexible base container filled with a phase change material with a phase change temperature identical to the desired temperature.
Claims
1. A thermal sink cooling cartridge, comprising: a base container having a bottom surface, an opening, and exterior side walls extending between the bottom surface and the opening and tapering outwardly from the bottom surface to the opening, said bottom surface and exterior side walls forming an outermost exterior surface of the fully-assembled thermal sink cooling cartridge, said bottom surface further comprising an expansion panel configured to expand in response to an increased pressure within the base container to maintain overall exterior dimensions of the thermal sink cooling cartridge in use; a thermoconductive cover having an undersurface coupled to and enclosing the opening of the base container and adapted to provide a thermally conductive interface between the thermal sink cooling cartridge and an external object placed on the thermoconductive cover in direct contact and to be maintained at a desired cooled temperature; a fluid tight seal interposed between the opening and the thermoconductive cover; and a phase change material comprising an aqueous material having a liquid phase and a solid phase, the solid phase being buoyant within the liquid phase, said phase change material entirely filling the base container in both the liquid and solid phases such that the phase change material is in continuous contact with the undersurface of the thermoconductive cover, wherein solidification of the aqueous medium induces the increased pressure within the base container.
2. The cartridge of claim 1, further comprising a molded feature in contact with the phase change material, the cartridge comprising a volume which reduces in response to the increased pressure to allow for expansion of the phase change material.
3. The cartridge of claim 1, wherein the thermoconductive cover is composed of a thermoconductive material selected from the group consisting of aluminum, copper, silver, an aluminum alloy, a copper alloy, a silver alloy, a titanium alloy, stainless steel, and a magnesium alloy.
4. The cartridge of claim 1, further comprising a temperature sensitive strip coupled to an outer surface of the thermoconductive cover.
5. The cartridge of claim 1, further comprising a contact surface to facilitate handling of the cartridge, wherein the contact surface comprises a portion of at least one of the expandable base container and the thermoconductive cover.
6. The cartridge of claim 1, wherein the phase change material is selected from the group consisting of water, purified water, and water containing an additive selected from the group consisting of glycerol, a salt, polyethylene glycol, an alcohol, a simple sugar, a complex sugar, and a starch.
7. The cartridge of claim 1, wherein the fluid tight seal is selected from a group consisting of an adhesive, a silicone-based adhesive, a compressed gasket, an o-ring, a compression band, a clamp, a crimped seal, a fusion weld, and a rim channel molded into a base portion of the expandable base container.
8. The cartridge of claim 1, further comprising at least one of a ridge, a groove, a peg, a hole, a texture, a feature, a protrusion, an encasement, and an indent to accommodate or receive an external object.
9. The cartridge of claim 8, wherein the external object is at least one of a biological sample, an organic material, an inorganic material, a food, dry ice, an electronic component, an automated machine, a stand, a refrigeration device, a computer chip, a sample tray, a sample tube, a container, an adapter for a container, and a sample rack.
10. The cartridge of claim 1, wherein the cartridge further comprises an external surface for compatibly receiving a storage housing.
11. The cartridge of claim 10, wherein the storage housing is composed of an insulating material selected from the group consisting of polyethylene foam, polypropylene foam, styrene foam, urethane foam, and evacuated containers.
12. The cartridge of claim 1, further comprising one or more ports that are used to access an interior of the expandable base container to add, modify, or replace said phase change material.
13. The cartridge of claim 1, wherein the expandable base container is composed of a material selected from the group consisting of polyethylene and polypropylene polymers.
14. The cartridge of claim 10 wherein the storage housing is a shipping container.
15. The cartridge of claim 1, wherein at least one magnet is attached to the thermally conductive cover.
16. The cartridge of claim 1, wherein the phase change material comprises an antimicrobial material.
17. The cartridge of claim 2, wherein the molded feature is a compressible element.
18. A thermal sink cooling cartridge, comprising: a base container having a bottom surface, an opening, and exterior side walls extending between the bottom surface and the opening, said bottom surface and exterior side walls forming an outermost exterior surface of the fully-assembled thermal sink cooling cartridge, the base container further having an internal volume, and at least one of the bottom surface and the exterior side walls being configured to flex outwardly to provide an increased internal volume of the base container; a thermoconductive cover having an undersurface and enclosing the opening of the expandable base container and adapted to provide a thermally conductive interface between the thermal sink cooling cartridge and an external object placed on the thermoconductive cover in direct contact and to be maintained at a desired cooled temperature; a fluid tight seal interposed between the opening and the thermoconductive cover; and a phase change material having a liquid phase and a solid phase, said phase change material entirely filling the internal and increased internal volumes in both the liquid and solid phases, respectively, such that said phase change material is in continuous contact with the undersurface of the thermoconductive cover, the liquid phase comprising a first volume equal to the internal volume, and the solid phase comprising a second volume that is equal to the increased internal volume.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
DETAILED DESCRIPTION OF THE INVENTION
(17) The present invention provides a passive cooling cartridge or thermal sink that can be used to regulate the temperature of objects placed in contact with the cover of or otherwise in close proximity to the cartridge. The cartridge comprises a flexible base container that contains an aqueous medium. The cover of the container is constructed from any thermally conductive material, often a material with a thermal conductivity in the range of 12 to 430 Watts per meter per degree Kelvin, and directly contacts the solid phase of the phase change material (on the side facing the cartridge interior) and forms a thermally conductive junction with external objects placed on it (the side facing away from the cartridge interior) for the purpose of cooling those objects and/or maintaining them at the phase change temperature.
(18) In some embodiments, the base container is constructed from a semi-flexible plastic or rubber material so that the container does not fracture or rupture, or the thermally conductive surface become distorted when an aqueous or other phase change material that expands upon solidification solidifies. In some embodiments the base container will have molded features that will allow for the expansion of the phase change material upon solidification. Such features include, but are not limited to, invertible recesses, relief cavities, expandable bellows, stress relief ridges, and/or compressible cavities. In other embodiments, the base container comprises an under ridge or protrusions for the purpose of supporting the cartridge on a surface while minimizing direct contact of the container base with the supporting materials. Other embodiments include ridges or projections that allow cartridges to be securely stacked while restricting lateral slippage. As the intended operation of the cartridge depends upon direct contact of the solid phase with the thermoconductive surface, in some embodiments the base container will have a taper to the side walls which will facilitate the separation of the solid phase from the walls shortly after conversion of the solid phase to liquid phase at the solid phase/container interface is initiated. This feature will allow the solid phase to be buoyant for materials for which the solid phase is less dense than the liquid phase (for example, water).
(19) Referring now to
(20) Sealant 115 interposed between an opening of the expandable base container 110 and the thermoconductive cover 105 provides a fluid tight seal. Thus, sealant prevents leakage of the aqueous medium 225 (
(21) In some embodiments, thermoconductive cover comprises a thermoconductive material, such as aluminum, copper, silver, gold, an aluminum alloy, a copper alloy, a silver alloy, a gold alloy, a titanium alloy, stainless steel, and/or a magnesium alloy. Cover 105 may further be constructed from an aluminum alloy sheet that has been type 2 anodized for corrosion resistance. In some embodiments cover 105 comprises a 0.20 inch thick aluminum alloy material, such as a 6000 series aluminum alloy. In particular, in some embodiments cover 105 comprises T-6061 aluminum alloy.
(22) With continued reference to
(23) In some embodiments, base container 110 accommodates an expanding volume of the aqueous medium, upon solidification, without rupture, failure of container seams, or significant distortion of overall dimensions of the base container. For example, in some implementations the expandable base container comprises at least one expansion panel 210, whereby the interior volume of the base container may expand in response to increased pressure within the container, as shown in
(24) With continued reference to
(25) In some embodiments, the undersurface of the thermoconductive cover 205 is laminated with a thin layer of plastic to enhance corrosion resistance. In some embodiments, the thermoconductive cover 205 further comprises one or more magnets whereby to facilitate coupling of the thermoconductive cover to an external object. In some instances, the one or more magnets are imbedded within the material of the thermoconductive cover 205. In other implementations, the one or more magnets are attached to any surface of the thermoconductive cover 205, wherein the one or more magnets magnetize the remaining surfaces of the thermoconductive cover.
(26) Referring now to
(27) In some embodiments, influx of lateral and root surface environmental heat into the cartridge assembly is limited by containing the cartridge in an insulating box 310. Insulating box 310 may be constructed from high density polyethylene foam. As shown in
(28) Referring now to
(29) Referring now to
(30) Some embodiments of the present invention further comprise a non-aqueous medium. For example, a thermal sink cooling cartridge of the present invention may include organic compounds which are capable of transferring heat to a thermoconductive cover of the present invention. The cartridge may further include ammonia or one or more waxes. For substances that have a solid phase that is more dense than the liquid phase, the cartridge can be, for example and without limitation, inverted for the purpose of operation. In such embodiments, a thermal interface with external objects may be accomplished by, but not limited to, the interface shown in
(31)
(32) Some embodiments of the present invention comprise various features and surfaces to accept or compatibly receive an external object. For example, the cooling cartridge may include a feature, a texture, a contour, and/or a shape which engages or interlocks with a feature, texture, contour, and/or shape of an external object. The cartridge may further include at least one of a ridge, a groove, a peg, a hole, a texture, a feature, a protrusion, an encasement and/or an indent to accommodate or receive an external object.
(33) The upper plate 640 is bonded to the plastic container 620 by an adhesive layer 645. The container undersurface comprises an inner recess that has molded bellows 630 for the purpose of allowing expansion of the cartridge contents. The cartridge is contained within a plastic shell housing 605 and 610 wherein it rests upon a molded shelf 625. The interior of the shell housing 615 can be filled with an insulating material such as, but not limited to, styrene or polyurethane foams. An adaptor feature 655 for the purpose of positioning upon or within external devices such as, but not limited to, robotic platens, shaker tables, or storage shelves, is shown.
(34) Referring now to
(35) With reference to
(36) Referring now to
(37)
(38) Referring now to
(39) Some embodiments of the present invention comprise a method for assembling the thermal sink cooling cartridge of the present invention. Some methods include a first step of providing an expandable base container, as described herein. For some methods, and aqueous medium is placed into the interior of the expandable base container prior to sealing the base container with a thermoconductive cover. In some embodiments, the base container is joined and sealed, by means of a flange feature, to the upper thermoconductive cover by a flexible adhesive or sealant, including, but not limited to, a silicone-based adhesive. Prior to joining the base container and the thermoconductive cover, at least one of the base container and the thermoconductive cover is treated with oxygen, such as by heating the surface with an oxygen-rich flame. In other embodiments, the base container is joined by ultrasonic weld of the base container material to a fused deposit of the same or a similar material on the cover.
(40) A method of assembly may further include a step for filling the interior of the expandable base container following assembly of the device. In these instances, a port is provided in at least one of the thermoconductive cover and the expandable base container, whereby the ports provide access to the interior of the base container. In some embodiments, and aqueous medium is inserted directly into the interior of the base container by pouring the aqueous medium through the port. In other embodiments, the assembled cartridge is submerged in a container of aqueous medium, wherein the aqueous medium displaces air within the interior of the cartridge via the port. Access or remaining air within the interior of the base container may be removed by applying a vacuum force to the cartridge via the port. The port is then sealed either temporarily or permanently, as may be desired. In some embodiments, it is desirable to provide further access to the interior of the cartridge, and therefore the port is temporarily sealed with a removable bung or plug.
(41)
(42) Referring now to
(43)
(44) In some embodiments, the thermoconductive cover may contain contours, projections, recesses (as shown in
(45) In some embodiments, the thermoconductive cover can contain embedded channels through which thermal energy can be introduced into or removed from the cartridge. For example, in some embodiments the channels are filled with thermoconductive materials that can extend beyond the limits of the cartridge to interface with external objects. Non-limiting examples of thermoconductive materials that can be used include copper, silver, aluminum, and heat tubes. Thus, in some embodiments the thermoconductive channels permit the use of the cartridge for applications where direct contact of the external object with the upper thermoconductive surface of the cartridge is not appropriate. Non-limiting examples of external objects include refrigeration systems, Peltier coolers, cold sinks, remote thermoconductive adaptors, and objects spatially restricted by functional limitations such as isolation chamber, robotic machines, electronic assemblies, semiconductor chips, heat exchangers, medical devices, and clean rooms.
(46) In some embodiments, the cover has sealable ports by which the phase change material may be inserted into the cartridge cavity or internal space. In other embodiments the thermally conductive cover may have phase change material filling ports that contain self-sealing valves such as Schrader valves. In other embodiments, the base container has sealable ports by which the phase change material is inserted.
(47) In some embodiments, the thermoconductive cover may further comprise embedded magnets for the purpose of temporarily mating the thermoconductive plate to external objects. The objects to be mated may include, but without limitation to, undercarriages of objects to be cooled, thermal conduits, thermally conductive adaptors.
(48) In some embodiments, the base container further comprises tapered or flared walls such that the solid phase of the phase change material may release and float free of contact with the base container following the initial thawing of the outermost portion of the phase change material.
(49) In some embodiments, the base container has an upper flange, ridge, or sleeve by which a sealed interface with the upper cover can be achieved. In some embodiments, the interface seal between the base container and the cover is achieved by an adhesive bond, as discussed previously.
(50) Referring now to
(51) In some embodiments, gasket 1620 comprises a portion of expandable base container 1610. For example, in some embodiments base container 1610 comprises a flexible material, such as Santoprene, which be compressed between thermoconductive cover 1605 and rigid backing ring 1635 to act as its own seal. In other embodiments, base container 1610 or thermoconductive cover 1605 comprise a composite material having an integrated surface layer which may be compressed to act as its own seal. Thus, gasket 1620 may include an independent component, or may include an integral part of base container 1610 or thermoconductive cover 1605.
(52) In some embodiments, the base container is an injection-molded synthetic material. In other embodiments, the base container material is shaped by vacuum or pressure molding. Further, in some embodiments the base container is a flexible bag.
(53) In some embodiments, the cartridge cavity is filled completely with an aqueous medium having a lower density in the solid phase such that the solid phase rises under buoyant forces to remain in constant contact with the underside of the upper thermoconductive cover. In some embodiments, the expandable base container is filled with an aqueous medium prior to sealing with the container with the thermoconductive cover. In other embodiments, a port is provided which provides access to the interior of the expandable base container. For these embodiments, the expandable base container is filled with the aqueous medium by submerging the cartridge into a pool or container of the aqueous medium. Remaining air within the cartridge may be removed by applying a vacuum line to the port, thereby drawing the remaining air from the interior of the base container.
(54) In some embodiments, the cartridge comprises handles, finger grip recesses, and/or ridges to aid in transport. In various embodiments, the cartridge has one or more features that provide secure interface between other cartridges and/or between a cartridge and an external housing. Thus, the thermal sink cooling cartridge of the present invention may further include various features and surfaces to facilitate handling of the device. Referring back to
(55) In some embodiments, the invention provides a cartridge that is selectively inserted into an insulating housing. In some embodiments, all or part of the cartridge is permanently mated with a housing. Such permanent mating can be beneficial, for example, and without limitation for insulating the cartridge, protecting the cartridge from impact damage, and/or secondary containment of the cartridge contents should leakage occur. The thermal sink cooling cartridge of the present invention may further include various features and surfaces to accept or compatibly receive an external storage housing. For example, an external surface of the cooling cartridge may include a feature, a texture, a contour, and/or a shape which engages or interlocks with a feature, texture, contour, and/or shape of an interior surface of a storage housing. A storage housing may include a container comprising an insulating material, such as polyethylene foam, polypropylene foam, styrene foam, urethane foam, and evacuated containers. In some implementations, the storage housing comprising a shipping container.
(56) In some embodiments, the insulation or storage housing directly contains the phase change material. In such an embodiment, the thermally conductive cover is bonded directly to the insulation material. Materials that may be used for such embodiments include but are not limited to closed-cell high density polyethylene foam. Cartridges constructed by this method may comprise undercut recesses on the underside of the insulation for the purpose of maintaining the overall exterior dimensions of the cartridge following the expansion of the phase change material.
(57) In some embodiments, the base container comprises a flange that can be used for suspending the cartridge in an insulated housing. In other embodiments the cartridge thermoconductive cover comprises a flange extension by which the cartridge is suspended in the insulation housing. The flange extension may be manufactured to a high tolerance relative to the top surface of the cover, thereby making the height of the top surface independent of the thickness of the adhesive joint. Precision in the height dimension will be of value in applications wherein the overall height dimension is critical. Examples may include but not be limited to robotic applications and manually operated volumetric dispensation machines.
(58) The cartridges of the invention may be made in any size and shape. The size, thickness, and overall dimensions of the cartridge selected for an application of interest are adjusted to provide the optimal, most functional, cartridge for that application. For illustration and not limitation, one can, for example, alter the internal volume of the cartridge to provide a required cooling duration (smaller volumes providing shorter duration). Illustrative volumes may be, for example, in the range of microliters to milliliters to liters and even thousands of liters.
(59) In some embodiments, the thermoconductive cover is manufactured by machining from billet material. In other embodiments, the cover is constructed from rolled sheet material. In other embodiments, the cover is constructed from cast or sintered metals.
(60) In some embodiments, the insulation housing may comprise permanent or temporary extensions or features for mating with external objects. The extensions may include, but not be limited to, flanges, rails, baseplates, bearings, floats, cushions, bumpers, slides, tracks, mounts, suspensions, shock absorbers, skids, cradles and frames. The external objects to which the insulation housing may mate with include, but are not limited to robotic or manual machine platens, mounting plates, racks, floors, rails, tracks, flanges, rails, baseplates, bearings, floats, cushions, bumpers, slides, tracks, mounts, suspensions, shock absorbers, skids, cradles and frames, and freezer racks, stations, compartments and drawers.
(61) In some embodiments, the cartridge may be used for warming purposes by increasing the temperature of the cartridge contents and using the cartridge as a thermal mass for transient temperature range management. In other embodiments, the cartridge may be used as a passive thermal buffer to counter transient temperature changes.
(62) In some embodiments, the cartridge may be use to control the temperature of objects during shipment, while in other embodiments, the cartridge may be use to control the temperature of food.
(63) Thus, the invention has a wide variety of aspects, embodiments, and applications, as reflected in the following examples and claims.
Example 1. Cartridge of the Invention Provides Superior Cooling
(64) An aqueous sample was placed into a microplate well of a microtiter plate, after which the microplate was placed onto a room temperature thermoconductive adaptor of the type shown in
Example 2. Alternate Cartridge of the Invention Provides Superior Cooling
(65) A cartridge of the invention as described in