US20020130131A1

US20020130131A1 - Thermal container

Info

Publication number: US20020130131A1
Application number: US10/100,794
Authority: US
Inventors: Hans Zucker; Werner Sommer; Matthias Worf
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-03-19
Filing date: 2002-03-19
Publication date: 2002-09-19
Also published as: DE10113183C1

Abstract

A thermal insulation container for storing materials at predetermined temperatures over extended periods including thermal energy storage units and means for substantially eliminating thermal conductors and providing improved insulation properties by mechanically absorbing temperature induced frictional forces. Highly efficient vacuum thermal insulators embedded within components of the container contribute significantly to its superior temperature maintaining characteristics.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention, in general, relates to a novel thermal insulation container wherein materials may be stored at a predetermined substantially constant temperature over extended periods of time and, more particularly, to a container provided with vacuum insulation, thermal energy storage units, at least one storage chamber, various highly insulating components and a temperature monitoring, storing and data transmission device. Containers of the kind here under consideration are suitable for storing their contents not only at high temperatures but also, and perhaps more importantly, at very low or cryogenic levels of temperature.

2. The Prior Art

Various usually double-walled containers for storing different media or materials, such as, for instance, low boiling point liquefied gasses, are well known. Also, containers are known for transporting or storing materials at temperatures ranging from very hot to very cold. Such containers are often provided with shells which are made from, or include, different insulating materials, such as, for example, polyurethane, Styropor®, cork plates, evacuated intermediate cavities and/or vacuum insulation panels. Thus, containers are known for transporting live fish, food, living organs, micro organisms and other materials which require storage or transportation at a substantially constant temperature. Storing such materials within a certain temperature range does not usually pose any problems, since temperature differences in stationary containers can easily be adjusted or compensated locally. Transport containers are, however, subject to different conditions which mitigate against guaranteed constant temperatures over extended periods of time, as would be of the utmost importance, for instance, in the context of transporting biological materials over long distances, such as during intercontinental flights, for example. Any undesirable changes in temperature may, and very often do, lead to spoiling of the stored material.

OBJECT OF THE INVENTION

It is, therefore, a primary object of the invention to overcome, or at least minimize, the disadvantages of known thermal containers and of insulating components and thus to provide a storage or transport container operable at substantially constant temperatures over extended periods of time.

It is a more particular object of the invention to provide a thermal container suitable for transporting and storing deep frozen biological specimens, organs, cultures and the like at a constant temperature in the range of from about −90° C. to −75° C. in excess of 50 and preferably more than 100 hours.

Another object of the invention is to provide thermal containers of the kind referred to the thermal energy storage units of which require recharging only after more than 100 hours.

It is a further object of the invention to provide a light weight thermal container which is simple to manufacture.

A still further object of the invention is to provide a thermal container of the kind referred to which offers a favorable ratio of net weight to tare weight and of net volume to tare volume thereby to reduce materials and costs.

Another object of the invention is to provide a container of the kind referred to which in general avoids the need for liquefied nitrogen or similar coolant.

SUMMARY OF THE INVENTION

In the accomplishment of these and other objects, the invention provides for a container, hereinafter sometimes referred to as a thermal container, which ensures stable temperatures by virtue of highly effective insulation properties as a result of the use of novel and favorable combinations of various insulating materials in which critical zones in particular, such as the transitional areas between internal and external walls, the access areas and the areas of transition between different structural materials are protected from, and insulated against, impinging heat. Sensory rechargeable or chemical thermal energy storage units may either be inserted into, or are incorporated in, the container to ensure substantially constant temperatures for periods of ≧140 hours.

In accordance with the invention the combination of individual insulating components is based upon the complementing use of

high vacuum super insulation in outer shells, including spacers and metalized reflexive foil having a heat transfer coefficient of about 0.1 mW/mK;

dimensionally stable foam insulation including reinforced margins and having a heat transfer coefficient of about 10 mW/mK;

high vacuum super insulation in cavities with supporting structure and a heat transfer coefficient of 0.1 mW/mK;

reflection materials between the inner and outer walls of the high vacuum super insulation;

vacuum and high vacuum insulating components made of plastic, glass, ceramics and/or metal with supporting structures provided in the evacuation zone and spacers and metal coated reflection foil for insertion in a dimensionally stable foam insulation;

known gettering techniques in the evacuated interior chamber and dispensing of the getter material from appropriate devices;

material-saving cambered container walls as well as material-saving and expanded connections between an outer and an inner shell moveable in two degrees of freedom for reducing the flow of heat by extending the heat path and for lowering the weight of the thermal container; and

alternative foil vacuum insulations (vacuum insulation panels) as highly effective heat shields with a heat transfer coefficient of about 4 mW/mk.

The alternatively used foil vacuum insulation as a highly effective heat shield is usually supported by a powder or by a filler and may be structured like a disk, plate, annulus, bowl, cylinder, tube or circular segment. Preferably, its wall elements and structure are rigidly encased in foam. In areas of potential heat bridges or thermal conductors, the foil vacuum insulation is arranged vertically or horizontally displaced.

The high vacuum super insulation consists of a double-walled system of an enclosed hollow body formed by external and internal walls disposed substantially parallel or concentrically of each other and having an internal atmosphere in the high vacuum range.

For the prevention of heat losses both ends of the internal wall are of reduced circumferential thickness and are extended to provide one or more bends, and they are welded to the external wall to form a vacuum seal. These ends offer at least two degrees of freedom and thus function in the manner of a resilient or expansive element. In accordance with the invention, the ends of the internal and/or external wall are configured such that they in effect provide an extended thermal path. Circumferential beads formed in the internal and/or external walls provide stability against implosion and make possible the use of walls of reduced thickness. In addition, the beads provide for increased elastic compensation between the internal and external walls.

The structurally stable foam insulation is inserted in bowl-shaped shells which may be made from stainless steel or plastic, for instance. The foam serves to arrest and protect embedded insulation components of many different shapes, as well as mechanically to stabilize enclosing, connecting or closing structures and to eliminate or at least reduce heat bridges or thermal conductors which would otherwise absorb or dissipate unwanted thermal energy.

The high vacuum super insulation of hollow bodies provided with supports in enclosing, connecting or closing structures consists of a casing which forms an internal space provided with internal supportive structures. The supportive structures partially or almost completely fill the internal space in one or more adjacent and/or superposed layers. The supportive structures consist of superposed or adjacent layers of circular or polygonal cells displaced in such a manner that only point contact exists between the walls of abutting cells. The supportive structures of circular or polygonal cells are a material forming vertically arranged cells made, for instance, from coated paper, glass, ceramic or plastic structures.

The supportive structures may also be annularly shaped substantially tube-like configurations (torus) or solid rings and may be annularly arranged within the internal space, preferably as several adjacent rings. The toroidal or solid ring supportive structures consist of fiber-glass reinforced plastic.

In accordance with the invention, insulating components are being proposed which are provided with evacuated zones having supportive structures therein. The insulating components are provided for particularly critical zones of thermal containers such as lids, insulating or annular flanges, pedestals as well as for connecting elements used for the stacking several containers in superposition. They are disposed within the walls of the lids, the pedestals and the connecting elements as well as of the insulating flanges. The walls are preferably made of plastic.

In accordance with the invention, a thermal container is being proposed which constitutes a closed hollow body formed by internal and external walls disposed in substantially parallel or concentric relationship and forming an annular enclosure for an internal atmosphere reduced to high vacuum pressure range. The opening at one end of the container is closed by a pedestal; the opening at the opposite end is closed by a lid. In an alternate embodiment, the other opening of the container may be closed by a lid recessed in an annular rim or flange. Furthermore, the thermal container may be provided with one or more thermal energy storage units as well as with a storage chamber.

The hollow body is preferably of tubular construction and forms a hollow cylinder the outer wall of which constitutes an external tube and the inner wall of which constitutes an internal tube. At their respective end portions the tubes are connected to each other by a hermetic seal. In the area of the hermetic seals the internal tube and the external tube are provided with circumferential structures or fillets, hereinafter called “fillets”, functioning as resilient or expansive elements to impart at least two degrees of freedom. These fillet complement or counteract any material deformations as may result from different temperatures affecting the internal and external walls. The fillet of the external and internal walls form an imaginary annular chamber the shape of which is a body which results from a planar figure moving along a closed curve as, for instance, by rotating the figure about the axis disposed in the plane of the figure without intersecting it. In accordance with the invention, the circumferential fillet at the front and rear ends of the internal and external tubes may be of different shapes; preferably, however, they are of double sine or arcuate cross-section. In any case, the fillet extend or prolong the heat path between internal and external tubes. Heat transfer is also reduced by these fillet in consequence of their material thickness being about one fourth less than the material thickness of the internal and external tubes.

In accordance with the invention, the pedestal closing one of the openings of the hollow body and the flange closing the other opening of the hollow body are held in their position by inwardly and/or outwardly protruding circumferential stabilizing elements near the respective end surfaces of the hollow body, or by frothing adhesives. Advantageously, the stabilizing elements are formed as beads. In order further to improve thermal insulation, the internal tube is provided with a super insulation coil consisting of spacers, radiation reflecting materials and, optionally, insertion of a chemical getter or of an adsorption material.

As mentioned before, at its upper and lower sections the thermal container is respectively provided with a flange for receiving a lid and a pedestal. These components for closing the opposite ends of the hollow body are made of highly insulating foam materials encased in a shell. Further highly insulating components are arranged in the respective shells of the flange, lid and pedestal,.

In another embodiment of the thermal container the lower end surface of the hollow body is provided with a double bottom. The double bottom consists of bulging sheet metal plates preformed in a predetermined manner. One of the plates closes the internal wall, the other plate closes the external wall, and between them they form an intermediate space connected with the space between the internal and external walls of the hollow body thus forming a single evacuation chamber. At their margins the bottom plates are crimped and the bulge or camber in a predetermined manner in the direction of their centers. The plates are preferably made of steel, and after having been respectively welded to the internal and external walls, they form resilient or expansive elements offering at least two degrees of freedom. Annular beads provided in the sheet metal plates constitute additional resilient or expansive elements. The connection between the plates and the respective external and internal walls is hermetically sealed. The material thickness of the plates is at least one fourth less than the thickness of the internal and external walls.

Supportive spacer elements are provided between the plates. As the space between the plates separated by the spacers is evacuated, the plates tend to camber towards each other in a predetermined manner. A conventional evacuation opening and a container for storing and dispensing getter material are provided at the outer bottom plate.

In accordance with the invention the bottom section of the container is seated in a pedestal consisting of a plastic shell the interior of which is filled by dimensionally stable foamed plastic. The major function of the pedestal is to provide protection for the container bottom and for the joints between external wall and bottom plate.

For purposes of being transported as large units, thermal container in accordance with the invention may be stacked in superposition such that several containers form a single storage unit when connected by one or more connecting elements. In a manner similar to the pedestal and the closing flange, the connecting elements are either affixed to circumferential inwardly and/or outwardly directed stabilizing elements or beads disposed at the respective end surfaces of the hollow body, or they are secured by frothing adhesive.

The insulating components, in particular those to be placed in the lid, insulating flange, pedestal and connecting element of the thermal container are encased by a single or multipart hard plastic shell in the interior of which different insulating units are embedded in dimensionally stable plastic foam. An insulating unit may be of shallow cylindrical configuration and is preferably used in the lid or pedestal of the thermal container. The insulating unit consists of a cylindrical wall the upper and lower openings of which are closed by preformed cambered plates preferably made from a web of stainless steel of a thickness at least one fourth less than the conventional walls of a vacuum insulated thermal container. In accordance with the invention, the two plates and the wall are provided in their marginal portions with circumferential fillet formed as resilient or expansive elements offering at least two degrees of freedom. Annular beads are provided as additional resilient or expansive elements in the two plates. Independently of the fillet, the plates are clinched at their margins and welded to the wall in a hermetically sealed manner to form a substantially shallow hollow body. The dimensions of the hollow body are such that it almost completely occupies the surface area of a lid or pedestal. In this manner, heat bridges are eliminated or at least minimized as much as possible. The interior of such a hollow body is almost completely filled by supportive structures, and after evacuation the interior essentially constitutes a finished insulation unit. The purpose of the supportive structures is to transmit forces between opposing plates, and their configuration is such that they are stacked in several layers in displaced or offset disposition. One or more layers of perforated foils and/or evacuation drainages, preferably layers of fiber glass mats, are inserted between one or more layers of the supportive structures. The supportive structures may be disposed in a circular, annular, segmental or pointed disposition, or such that they almost completely fill the interior of the hollow body.

An insulating unit of this kind is positioned in a lid or pedestal of a container so that the wall of the insulation unit contacts neither the plastic shell of the lid nor of the pedestal. The insulating unit is encased, and thus rendered immobile, in plastic foam within the hard plastic shell of the lid or pedestal. In addition, one or more layers of a reflection material are embedded in the lid and in the pedestal as an additional radiation shield against the ambient atmosphere. The reflection material may also be placed in the hard plastic shell. Once the lid and the pedestal have been filled with foam, they are closed by further parts of precisely fitting hard plastic shells and sealed by seams between the parts of the shell. It is within the ambit of the invention so to fabricate the pedestal that it precisely fits the external wall of the container. In this manner, only one seal would be required between the rim of the pedestal and the casing of the container.

Yet another insulating unit is proposed for the lid and the pedestal. Instead of placed separately into the lid or pedestal, the insulating unit is specially constructed integrally with the lid or the pedestal. To this end, given a particular configuration and proceeding from the exterior to the interior, the following layers of different materials are adhesively connected to, or sealed with, one another. An exterior curable or hardenable cover layer, preferably made of epoxy resin and provided with an inserted radiation reflection foil is followed by several laminated layers. The lamination is preferably made of fibre glass and epoxy resin. Depending upon the structure and configuration of the lid and the pedestal, cavities between individual layers are filled with plastic foam. Metalized plastic foils, preferably compound aluminum foil or metal foils, are alternatingly embedded between layers of fiber glass mats such that by inserting supportive structures in the interior of the lid and pedestal, a cavity is formed in a diffusion tight foil which can be evacuated. Within an insulating unit constructed in this manner there may be arranged supportive structures of the kind mentioned before. Several layers of fiber glass mats are embedded between such supportive structures. In accordance with the invention, layers of fiber glass mats are also provided for completely enclosing the supportive structures. The properties of the fiber glass mats are selected such that they function also as evacuation drainages. Preferably, perforated reflection foils are additionally disposed between layers of supportive structures. The interior of the insulating unit is evacuated in the conventional manner by way of an evacuation cock. The evacuation cock is suitably connected to the upper median lid portion so that in case the vacuum decreases over time, the insulation unit may again be evacuated from the exterior. During fabrication of the lid or pedestal the insulating unit is encased in further laminate layers and/or foamed plastic such that it cannot lose its shape.

As described supra, both the insulating unit with its tubular wall and cambered plates and the insulating unit with a hollow cylindrical interior are provided with fillets closely adjacent to their seams or welding seams. These fillets constitute resilient or expansive elements providing for at least two degrees of freedom. As regards the fillets reference is made to their previous description.

A connection element will be used for connecting two or more thermal containers in superposition to form a larger unit in the manner referred to supra. Such connection element would constitute a particularly critical zone. For that reason, a further embodiment of an insulating unit is inserted into the connection element. It is of double or end-to-end tubular structure and may be used either as a connection element or as an annular container flange for receiving a lid to close the container. The insulating unit consists of an internal and an external cylindrical tube which are vacuum sealed together at their respective ends by a welding seam. They thus form a hollow cylindrical body and the space formed between them is partially or almost completely filled with supportive structures for transmitting forces between the internal and external tubes.

In the interior of the thermal container there are provided thermal energy storage units, such as, for instance, sensory storage devices, latent storage devices or chemical storage devices. The thermal energy storage units may be of different geometric configurations. They may be inserted as single or multiple layered plate elements near the lid and/or pedestal. Depending upon the materials to be stored, the thermal energy storage units may also be inserted in the storage chamber of the thermal container as cylindrical, hollow cylindrical, planar, segmental or sectoral bodies.

The thermal container is provided with a conventional temperature measuring device, the data of which, as well as data regarding location, stored material, temperature curve and other data may be retrieved, stored and reset at any time. A connection between data retrieval and processing of several containers is also provided.

Since the goods such as, for instance, transplant organs, to be shipped in containers in accordance with the invention usually are rather valuable, it is desirable to utilize the most up to date and, in the event, most reliable devices, such as, e.g., chip cards incorporating a temperature recording function. Thus, a chip card incorporating sensor, memory, battery and time-defining elements may serve to identify the goods being transported.

The containers including the specific insulating components and insulating units in accordance with the invention may either be used as individual or as stacked containers. The thermal container proposed by the invention is suitable for the transportation and storage over extended operating times in very different temperature ranges, in connection with, for instance,

biological materials in general, for instance living cell cultures, at 37° C.;

classic storage of thrombocytes at about 22° C.;

whole blood at about 4° C.;

blood plasma at about −40° C.;

cell cultures, umbilical blood, skin, and others at −90° C. to −75° C.

The container in accordance with the invention is also suitable for operation in other temperature ranges.

Thermal containers fabricated in the manner described ensure a useful life of the evacuation chamber and of the insulating units in lid, pedestal, insulation flange and connection element of at least five years. At a temperature range between about −90° C. and −75° C., and provided appropriate thermal energy storage units are being utilized, the operational period of the thermal containers lasts about 140 hours. At other temperature ranges the operational time will differ accordingly.

DESCRIPTION OF THE SEVERAL DRAWINGS

The novel features which are considered to be characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, in respect of its structure, construction and lay-out as well as manufacturing techniques, together with other objects and advantages thereof, will be best understood from the following description of preferred embodiments when read in connection with the appended drawings, in which: [0052]
FIG. 1 is a view in axial section of a thermal transport container in accordance with the invention; [0053]
FIG. 2 is a view in partial section of an external tube; [0054]
FIG. 3 is a view in partial section of an internal tube; [0055]
FIG. 4 is a view in partial section of a rim portion of a prior art container; [0056]
FIG. 5 is a view in partial section of a rim portion of a container in accordance with the invention; [0057]
FIG. 6 is a view in partial section of a rim portion of one embodiment of a thermal container in accordance with the invention; [0058]
FIG. 7 is a view in partial section of a rim portion of another embodiment of a thermal container in accordance with the invention; [0059]
FIG. 8 is a view in partial section of a rim portion of three different embodiments of a thermal container in accordance with the invention; [0060]
FIG. 9 is a view in axial section of two stacked thermal containers in accordance with the invention; [0061]
FIG. 10 is a view in partial section of the bottom portion of a thermal container without pedestal; [0062]
FIG. 11 is a schematic view in section of a lid including insulation component for a thermal container in accordance with the invention; [0063]
FIG. 12 is a schematic view in section of a pedestal including insulation component for a thermal container in accordance with the invention; [0064]
FIG. 13 is a schematic view in section of the structure of a connection element including insulating component for a thermal container in accordance with the invention; and [0065]
FIG. 14 Is a schematic view in section of the structure of a lid including a further embodiment of an insulation component for a thermal container in accordance with the invention.[0066]

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

EXAMPLE 1

A thermal container in accordance with the invention will be described using as an example a container for transporting different kinds of cell cultures at a temperature range of about −80° C. [0067]
FIG. 1 depicts a [0068] thermal transport container 1 in axial section. It includes a casing 30, a lid 12 and a pedestal 9. The interior of the container 1 constitutes a storage chamber 17 with thermal energy storage units 3 protruding from and complementing the lid 12 and the pedestal 9 respectively. Before being placed in the chamber 17, the thermal energy storage units 3 would have been cooled to about −120° C. At its upper section, the rim of the container 1 is encompassed by an insulation flange 11. The lid 12 is seated in an opening formed centrally of the insulation flange 11. The insulation flange 11, the pedestal 9 and the lid 12 each consist of a generally bowl-shaped member made of plastic and of one or more conventional and preferably foamed insulation materials. Foil vacuum insulations configured as disks, plates, rings, pots, cylinders, tubes or annular segments are disposed as insulating components 10 within the insulation materials. It is within the scope of the invention to structure the insulating components 10 as vacuum or high vacuum containers made of plastic, glass, ceramic materials, and/or metal provided with supportive structures in their evacuated zones, and of reflective materials. The vacuum insulating components 10 are embedded in insulating foam within the plastic shell members of lid 12 and pedestal 9 as well as, optionally, in the insulation flange 11.
At their exterior, the [0069] thermal container 1 and its lid 12 are respectively provided with handles 31 and 32. The container is also provided with closure and security devices.
The [0070] casing 30 consists of a double-walled tubular body which in the embodiment shown is preferably made of a sheet or web of stainless steel. At its internal wall or tube 15 the tubular double-walled body is provided with a super insulation coil consisting of a spacer and a radiation reflecting foil. A chemical getter or an adsorption material may also be inserted.
FIGS. 2 and 3 respectively depict partial sectional views of an external wall or [0071] tube 33 provided with an evacuation cock 34 and an internal wall or tube 15 as components of the casing 30. At several positions, the external tube 33 is provided with outwardly protruding circumferential beads 35. The internal tube 15 is provided at its upper and lower edges with outwardly extending fillets 36 which in cross-section are shaped in the manner of an S or double sine curve.
For a better explanation of the invention, FIG. 4 depicts the rim section of a prior art container, including a [0072] lid 41, in partial section.
The container rim portion shown in FIG. 4 consists of an [0073] external wall 37 with an internal vessel 38 and an outer wall 39. An insulating material 40, usually made of polyurethane, Styropor®, glass wool, cork plates or other material, is embedded within the wall 37. It is also known to provide vacuum pressure within the wall 37. Where vacuum is used to provide thermal insulation, the internal and external walls are usually made of stainless steel or aluminum alloy sheets of a thickness not less than 2 mm. Materials of lesser thicknesses often lead to fractures, especially at the connections between internal and external walls, and to fissures and ruptures of welded seams or implosions of the container wall. It is important to note, however, that the transition zone between internal and external walls or the rim portion of the container in fact constitutes a heat bridge or thermal conductor of the kind causing high temperature losses by absorbing or dissipating thermal energy.
FIG. 5 is a partial view of the rim portion of a container in accordance with the invention. An internal tube or [0074] wall 15 of the container is made of a stainless steel sheet of no more than 0.6 mm thickness, and its top and bottom transitional areas (only the upper transitional area is shown in FIG. 5) are provided with a radially S-shaped fillet 36 circumferentially extending around the internal tube or wall 15, with its outermost leg 42 being long relative to its S-shaped bends and provided with a lip 43.
The end of the [0075] external tube 33 is chamfered slightly inwardly towards the lip 43 of the double sine or S-shaped fillet 36, and during fabrication of the casing 30 it is welded to the internal tube 15 at the seam 44. The connection between internal tube 15 and external tube 33 at the opening opposite from the lid 12 or insulation flange 11 is substantially identical to the lid 12.
The [0076] external tube 33 is disposed around the internal tube 15 such that it forms therewith a hermetically sealed hollow cylinder wherein a high vacuum super insulation 13 in the range of ≦10⁻⁴Pa is generated by way of an evacuation cock 34 to ensure a useful operational life of the vacuum and super insulation of about five years. The vacuum is stabilized by gettering or insertion of an absorption material.
The double-sine or S-shaped [0077] fillet 36 makes the connection between internal tube 15 and external tube 33 resilient. In fact, the S-shaped fillet 36 constitutes a resilient or expansive element providing at least two degrees of freedom. In accordance with the invention, the fillet 36 may, however, be structured in whatever manner ensures an extended heat path.
As mentioned supra, the thickness of the material of [0078] internal tube 15 is 0.6 mm. By drawing the material, its thickness, in the area of the double-sine or S-shaped fillet 36, is deliberately reduced to 0.4 mm. This results not only in a substantially reduced heat flow but also in an extended heat path in consequence of the double-sine or S configuration of the fillet 36. The special structure provides for the lowest or weakest possible heat bridges or thermal conductors.
As shown in FIG. 5, the entire container rim section is encased by the [0079] insulation flange 11. The flange 11 is press-fitted onto the container rim by stabilizing elements such as outwardly and/or inwardly bulging beads 45. Alternatively, the flange 11 may be formed in situ of insulating foam molded directly to the container rim, by special molds. In this connection, it has been found to be particularly advantageous if, in accordance with the invention, the insulation flange 11 is cast within a shell and if part of it extends along the internal tube or wall 15 of the container over the S-shaped fillet 36 and along its outer leg 42, its lip 43 and downwardly along the external tube 33 to be anchored to a bead 45. The overlapping rim 46 thus created provides for additional and securely anchored insulation.
The [0080] insulation flange 11 is disposed securely around the upper rim of the container and seals it. In connection with the reduced material thickness inherent in the circumferential beads 45, the overlapping rim 46 extending, as described, along the outer wall 33 reduces heat bridges in the external wall 33.
The [0081] pedestal 9 is attached to the lower container rim in a manner similar to the mounting of the flange 11. The pedestal 9 is made as a compact structure from an encased insulating material and is provided with feet and/or rollers. It is also used as a receptacle for one or more conventional thermal energy storage unit 3. As in the lid 12 and insulation flange 11, insulating components 10 are also embedded in the encased foam of the pedestal 9.
The [0082] lid 12 is also made of an insulating material encased in a shell and is set in the insulation flange 11 to form a secure seal therewith. To complement the thermal energy storage units 3 at the pedestal 9, one or more thermal energy storage units 3 are disposed in the interior of the transport container near the lid 12. The thermal energy storage units 3 used may be rechargeable sensory storages, latent storages or chemical storages.
The [0083] insulation flange 11 is provided with a conventional temperature measuring, memory and data transmission device not shown in the drawing, as well as with one or more closure and locking devices. To prevent freeze-locking of the closure devices, appropriate vent slots or condensation ducts are provided in the insulation flange 11.
The hollow cylinder thus fabricated of stainless steel sheet of 0.6 or 1 mm maximum thickness and closed at the opening at one end by an [0084] insulation flange 11 and lid 12, and by a pedestal 9 at the opening at the opposite end ensures a useful operating period or cycle time of up to 140 hours in a temperature range of −90° C. to −75° C.

EXAMPLE 2

A [0085] transport container 1 similar to Example 1 is provided, in accordance with the invention, with an insulation flange 48 which tightly and sealingly engages the internal tube or wall 15, the leg 42 and the lip 43 which in the area of the double-sine or S-shaped fillet 36 forms an annular cavity. In the present context, “annular cavity” is intended to connote a chamber similar to a body resulting from moving a planar figure along a closed curve—for instance by revolving about an axis disposed in the plane of the figure without intersecting it. In the embodiment shown in FIG. 6, the figure chosen resembles the segment of a circle limited by one of the curves of the S-shaped fillet 36 and the marginal surface 50 of the insulation flange 48, the rotational axis of the figure being the axis of symmetry of the transport container 1. In accordance with the invention, the annular cavity 49 of the container described need not be shaped like a segment of a circle; it may have other profiles as well.
Accordingly, instead of being S-shaped [0086] fillets 36, the connections between internal tube 15 and external tube 33 may be structured differently, for example, as rounded fillets directed obliquely in an upward direction or as consecutive double-S-shaped bends.
It will be understood that such different profiles at the transition between the [0087] internal tube 15 and external tube 33 may be analogously applied at the pedestal 9, or that the transitions of the container of Example 1 may also be configured in this manner.
The cavity or [0088] annular chamber 49 is filled with a thermally insulating and preferably frothing adhesive when the insulation flange 48 is securely mounted or press-fitted over the bead 45.
In accordance with the invention, the elements of Examples 1 and 2 of configuring the transitional zone between [0089] internal tube 15 and external tube 33 and more particularly those relating to securing the insulation flange 11 may be combined.

EXAMPLE 3

A [0090] transport container 1 substantially similar to that of Example 1 differs structurally at the rim of the openings of the hollow body, i.e. at the connections between its internal tube 15 and its external tube 33. FIG. 7 offers a sectional view of the area of a container rim of the embodiment to be described.
An [0091] annular flange 51 is provided close to the outer circumference of the external tube 33 of the casing 30. A gap 52 in the flange 51 is filled with a suitable adhesive, for instance a silicon adhesive, after the flange 51 has been attached to the casing 30. This results in a particularly sturdy connection between the flange 51 behind the bead 45 in the external wall 33. Such a structure is suitable for closing either end of the tubular hollow body.

EXAMPLE 4

A [0092] transport container 1 generally similar to Example 1 has a differently structured rim at the openings of the hollow body. The transitional zone between its internal tube 15 and its external tube 33 differs as may be seen from the four configurations depicted in FIG. 8. At their top and bottom ends the internal tube 15 and the external tube 33 converge approximately semi-circularly and are joined by a welded seam 44. In addition, the internal tube 15 is provided with outwardly and inwardly directed beads 45 and 54. This results in a reduced material thickness and, hence, provides for a heat path of extended length.
Three further examples shown in FIG. 8 depict variations of the connections between [0093] internal tube 15 and external tube 33. Prior to being joined by the welding seam 44, the two tubes are shaped in different ways. Each one of these variations does ensure at least two degrees of freedom between the tubes and thus accommodates the desired properties of resiliency and expansion.

EXAMPLE 5

At the rim of the openings of the hollow body, a [0094] transport container 1 of the kind generally similar to Example 1, is structured as described in the previous examples. FIG. 9 depicts two stacked containers 1 which are releasably connected to each other by a connection element 55. In essence, the connection element 55 constitutes a double insulation flange 11; 48; 51 structured for receiving casings 30 in its opposite surfaces. The connection between two casings 30 is established as previously described with the stabilizing elements or beads acting as anchoring means. Its construction as a highly insulating body is not unlike that of the lid 12 and pedestal 9 previously described. Preferably, the insulating component 10 is of annular configuration and occupies as much space or volume as possible within the foam insulation of the connection element 55. The connection element 55 is of annular shape so that the storage chamber 17 of the upper container 1 may be connected with the storage chamber 17 of the lower container to form a single larger chamber.
For reasons of structural stability, the [0095] connection element 55 is provided with honey-comb supportive structures of the kind described in Example 1. The connection element is also encased in a substantially rigid plastic shell.

EXAMPLE 6

As shown in FIG. 10, at the lower end the [0096] container 1 the internal tube 15 and the external tube 33 are closed by convexly and concavely crowned metal sheets 6, 6′ forming a double bottom. The margin of a preformed and crowned circular sheet 6 of a diameter corresponding to the inner diameter of the internal tube 15 is welded to the rim of the internal tube 15 along a seam 44 to form a hermetic seal. A preformed crowned sheet 6′ is similarly connected to the external tube 33 along a welding seam 44. Both sheets 6, 6′ are provided with circular beads 8. Before the crowned sheet 6′ is affixed to the external tube 33, a supportive structure 4 is introduced into the chamber formed between the two sheets 6, 6′ for keeping them apart. Closing the lower openings of internal and external tubes 15, 33 by the crowned sheets 6, 6′ results in a hermetically sealed chamber between the tubes 156, 33 which is connected with the space between the two sheets 6, 6′. The internal atmosphere of the chamber is evacuated by an evacuation cock (not shown in FIG. 10). Since the thickness of the sheets 6, 6′ at about 0.4 mm to about 0.6 mm is relatively insignificant, the sheets 6, 6′, under vacuum pressure, will tend to buckle towards each other. Such buckling is, however, resisted by the supportive structure 4 within the chamber.
A [0097] cartridge 7 for storing and dispensing a getter material is provided at the outer sheet 6′. The cartridge 7 is structured and arranged such that getter material may be dispensed into the super insulation high vacuum chamber 13 for replenishing as needed, without affecting the vacuum.
As described in Example 1, the applied supportive structure is a cellular one. The [0098] supportive structure 4 is placed into the chamber in a side by side or stacked manner in order partially or almost entirely to fill the chamber. In FIG. 10, the supportive structure between the sheets 6, 6′ is arranged in a circular pattern in two superposed layers offset such that the ends of its cellular walls contact each other at points only. Reflective materials (not shown in FIG. 10) are disposed between the sheets 6, 6′ and/or the layered supportive structures 4. Preferably, the reflective materials, particularly those between the support element layers, are perforated.
The bottom of the [0099] container 1 formed by the crowned sheet 6′ is encased in a pedestal made of a plastic shell to which the container 1 is secured by foamed plastic. Insulating components otherwise inserted in the pedestal are not needed since the pedestal serves only as a protection device.
The useful life of the high vacuum [0100] super insulation 13 evacuated to ≦10⁻⁴Pa of a container bottom made in the described manner by connection of the internal tube 15 and the external tube 33 with the crowned sheets 6, 6′, lasts up to five years and ensures safe storage or transport of biological substances for ≦140 hours at temperatures of −90° C. to −75° C. At or towards the end of the constant temperature time, the thermal energy storage units may be exchanged or recharged.

EXAMPLE 7

FIG. 11 depicts a [0101] lid 12 of a vessel or transport container 1 which is operable at different temperatures.
In this embodiment, the [0102] lid 12 is formed of plastic and within its foamed core, there is embedded a flat cylindrically configured insulating body 2. The cylindrically configured insulating body 2 consists of a cylindrical wall 5 of steel of 0.4 mm thickness. Each end of the cylindrical wall 5 is closed by a crowned sheet 6. The margins of the two crowned sheets 6 are connected to the wall 5 by a vacuum-tight welding seam 44.
In accordance with the invention, the two [0103] sheets 6 and the wall 5 are provided at their marginal sections with circumferential fillets similar to those shown in FIGS. 12 and 13 at the end of the tubes 15; 33 or 18; 19. The circumferential fillets are formed as resilient or expansive elements providing at least two degrees of freedom. The two sheets 6 are provided with circular beads as additional resilient or expansive elements. While they are not depicted in the drawing, they nevertheless form an element of the invention.
In the interior of the insulating [0104] body 2, there are provided cellular supportive structures 4 disposed in several stacked layers. The interior atmosphere of the insulating body 2 is evacuated by way of an evacuation cock or opening not shown in FIG. 11. During the evacuation process the thin-walled sheets 6 tend to bulge towards each other but are prevented from collapsing by the supportive structures 4 between them. The configuration of the supportive structures depends upon the insulation body 2 and may either partially or completely fill the evacuated chamber in an annular pattern. Perforated foils are placed between the individual superposed offset supportive structures.

EXAMPLE 8

FIG. 12 depicts a [0105] pedestal 9 with an internal latent thermal energy storage unit 3. The pedestal is arranged at the bottom section of a thermal or transport container 1 and tightly closes the container. The pedestal 9 is provided with a cylindrically configured insulating body 2. The insulating body is immovably embedded in the foamed core of the pedestal 9 and is sealed at its margins. The pedestal 9 consists of a hard plastic shell.
In principle, the structure of the insulating [0106] body 2 and of the supportive structures 4 disposed in the interior thereof is identical to that in the lid 12 described in example 7. Accordingly, high vacuum super insulation is also ensured for the pedestal 9.

EXAMPLE 9

FIG. 13 depicts a partial section of two [0107] thermal containers 1 connected to each other at the ends of their internal and external tubes 15, 33. The schematically indicated and superposed containers 1—as described in greater detail in Example 5—are intimately connected to each other by a connection member 55. The connection member 55 consists of a hard plastic shell with an insulating body 10 immovably embedded in the dimensionally stable foam in the shell. In this embodiment, the insulating body 10 consists of a cylindrical internal tube 19 and a cylindrical external tube 18 joined in a vacuum tight manner at their ends by a welding seam 44. Near the hermetic seal at the internal tube 19 and/or the external tube 18 there are provided circumferential fillets structured as resilient or expansive elements providing at least two degrees of freedom. In the example shown, fillets are provided only at the internal tube 19.
[0108] Supportive structures 4 similar to those shown in Example 7 are provided in the chamber of the insulating body 10. Here, too, the supportive structures serve to transmit or balance such forces as may arise between internal tube 19 and external tube 18 during evacuation of the internal atmosphere of the insulating body 10. The insulating body 10 is structured as a double cylinder and occupies the largest possible space or volume within the dimensionally stable foam insulation of the connection element 55. To avoid or at least minimize heat bridges, the insulating body 10 overlaps the ends of internal and external tubes 15, 33 of the container 1. In this manner, excellent thermal insulation may be provided to the internal chamber made up of several stacked thermal containers 1. Using suitable thermal energy storage units, the stacked containers 1 have an operational period of about 140 hours at temperatures ranging from about −90° C. to about −75° C. Other temperature ranges result in different operating periods.
In accordance with the invention (but not shown in the drawings), the external tube [0109] 18 of the insulating unit 10 may, at its center section, be configured such that the space between the casing of an upper and a lower container is substantially occupied towards the welding seams 44 of external tube 33 and internal tube 15. This improves the insulation, and any heat bridges between external tube 18 of the insulation body 10 and internal tube 15 of the container 1 are further minimized.

EXAMPLE 10

The following description is not shown in any drawing. [0110]
An [0111] insulation flange 11 for receiving a lid 12 is structured similarly to an arrangement, structure and insert of an insulation body 10 of the kind provided with an internal tube 19 and external tube 18 as well as internal supportive structures 4 within a connection element 55.
For closing the [0112] container 1, the lid 12 is recessed in the insulation flange 11. Similar to Example 9, an insulating body 10 is disposed within the annular flange 11 as close to the margin of the lid 12 and of the container 1 as manufacturing techniques permit, in order to minimize or totally eliminate heat brides. Such an arrangement may be fabricated by forming the insulation flange 11 of a hard and preferably two-part plastic shell into which the insulating body 10 is then inserted. Any remaining voids in the interior of the shell are then filled with dimensionally stable plastic foam.

EXAMPLE 11

In the embodiment shown in FIG. 14, the [0113] lid 12 including insulating body 14 is made substantially of plastic. The insulating body 14 is encased in one or more layers of a metalized plastic foil 22 or thin metal foil deposited on one or more layers of fiber glass mats 23 which are supported by one or more layers of supportive structures 4. In the embodiment shown there are two layers of supportive structures. The layers of fiber glass mats 23 and of metalized plastic foil 22 or thin metal foil between the supportive structures 4 are perforated to facilitate quick and substantially complete evacuation of the internal chamber. One or more tiers of laminate layers 21, preferably made of epoxy resin bonded fiber glass, are arranged around the insulating body 14. The lid 20 is coated with a cover layer 20, preferably of epoxy resin. One or more layers of a metalized plastic foil 22 or of thin metallic foil are embedded in the cover layer 20. During manufacture of the lid 12, the lower portion of the lid 12 facing the interior of the container 1 is made first, followed by the application of several tiers of laminate layers 21 to its extending upper marginal portion for imparting structural stability. Finally, the upper portion of the lid 12 is provided with a cover layer 20, and a handle 32 is attached. The interior of the insulating body 14 is evacuated in a well-known manner by way of an evacuation cock (not shown in FIG. 14) to form a high vacuum super insulator. For practical purposes, this may be done by the upper internal section of the lid.
The multi-layered [0114] supportive structures 4 are made of connected polygonal cell structures as has been described in prior examples. Fiber glass mats 23 and/or metalized plastic foils 22 are interposed where the supportive structures are stacked in an offset manner. The complete structure of the lid ensures positive sealing and bonding of the metalized plastic foil 22 and a high vacuum having a useful life in excess of one year. For reasons of stability, the fiber glass mats 23 in the insulating body 14 may for special requirements be of a special thickness. In such conditions a thicker fiber glass mat layer 23 may be utilized as an evacuation drain.
In accordance with the invention, a structure similar to the [0115] lid 12 of high vacuum insulation properties as described in this embodiment is also used in connection with the pedestal 9. In principle, the insulating body 14 thus takes the place of the cylindrically structured insulating body 2 described in Example 8 and FIG. 12. In contrast to Example 8, the insulating body 14 is not immovably embedded in plastic foam, but is formed instead by several layers of metalized plastic foil 22, fiber glass mat layers 23 and laminate layers 21, all of which are sealed and bonded together by epoxy resin.
The use of such an insulating [0116] body 2; 14 in the lid 12 and in the pedestal 9 and of a insulating body 10 in the connection element 55 and in the insulation flange 11 results in the greatest possible decoupling or insulation of the interior of the thermal container 11 from ambient atmosphere.
It will be understood by those skilled in the art that the invention is by no means limited to the embodiments specifically described herein; but that the various structural elements and configurations may be interchanged to form different novel combinations. Nor is the invention confined to movable thermal containers of the kind referred to. It is equally applicable to stationary containers. In any event, the containers may either be equipped with integrated temperature control and compensating apparatus or they may be designed for connection to external apparatus of that kind. [0117]

Claims

What is claimed is:

1. A thermal container, comprising:

a casing forming an open-ended substantially cylindrical chamber and comprising substantially coaxially disposed external and internal cylindrical walls forming an open ended annular chamber;

means for resiliently and expansively connecting the external and internal walls along circumferential margins at at least one end thereof to provide at least two degrees of freedom between the external and internal walls;

an annular insulation flange encasing the connected ends and extending over a portion of the external and internal walls in intimate contact therewith;

a lid releasably seated in the flange for selectively closing one end of the cylindrical chamber;

thermal insulators embedded in the flange and in the lid; and

means for closing the opposite end of the cylindrical chamber.

2. The container of claim 1, wherein the means for connecting comprises a fillet of substantially S-shaped cross section integrally formed with one of the external and internal walls and having a free end connected to an end of the other of the external and internal walls by a welded seam.

3. The container of claim 2, further comprising at least one circumferential bead in at least one of the external and internal wall.

4. The container of claim 3, wherein the insulation flange extends over the bead.

5. The container of claim 3, wherein the external wall is provided with means for evacuating the annular chamber.

6. The container of claim 2, wherein the external and internal walls are formed of sheet metal of predetermined material thickness and wherein the material thickness of the fillet is about one fourth less than that of the walls.

7. The container of claim 1, wherein the means for closing the opposite end of the cylindrical chamber comprises first and second plates disposed at a predetermined spacing from each other and respectively connected to the external and internal walls by a hermetic seal thereby forming a chamber integral with the annular chamber.

8. The apparatus of claim 7, further comprising means in the chamber for maintaining the spacing between the first and second plates.

9. The apparatus of claim 7, wherein the spacing means comprises at least one layer of open cell structures.

10. The container of claim 1, wherein the thermal insulator in the lid comprises a substantially cylindrical cavity.

11. The container of claim 2, further comprising a second fillet integrally formed with the opposite end of one of the external and internal walls and provided with a free end connected to the other of the external and internal walls by a welding seam.

12. The container of claim 11, further comprising a pedestal provided with an annular flange encasing the opposite end of the external and internal walls and extending in intimate contact over a portion of the surfaces thereof.

13. The container of claim 12, wherein the annular flange and the pedestal are made of foamed plastic encased in a hard shell.

14. The container of claim 11, wherein the hard shell comprises a plurality of joined sections.

15. The container of claim 10, wherein thermal insulators comprising at least one evacuated cavity containing at least one layer of supportive structures and enveloped by at least one layer of metalized impervious foil bonded by resinous adhesive to at least one layer of fiber glass mat are embedded in the annular flange and in the pedestal..

16. The container of claim 15, wherein the cylindrical cavity is formed of sheet metal and comprises a tubular wall forming first and second axial openings hermetically sealed by sheet metal plates.

17. The container of claim 16, wherein the sheet metal plates are provided with circular beads.

18. The apparatus of claim 8, wherein a supportive structure is provided within the thermal insulators.

19. The apparatus of claim 18, wherein the supportive structure comprises at least one layer of cellular structures.

20. The apparatus of claim 19, wherein supportive structure is made of fiber glass reinforced plastic.

21. The apparatus of claim 19, wherein the supportive structure comprises a plurality of superposed layers axially displaced for providing point contact between open cell structures thereof.

22. The apparatus of claim 21, further comprising a perforated web between the axially displaced layers.

23. The apparatus of claim 1, wherein the annular flange comprises two substantially identically formed axial surfaces for axially connecting two containers.

24. A thermal insulation unit, comprising:

an open ended substantially tubular member;

first and second plate members for closing the open ended tubular member;

at least one fillet of substantially S-shaped cross-section integrally formed with one of the tubular member and first and second plate members and sealingly connected to the other of the tubular member and first and second plate member for providing two degrees of freedom therebetween.