U.S. patent application number 10/100794 was filed with the patent office on 2002-09-19 for thermal container.
Invention is credited to Sommer, Werner, Worf, Matthias, Zucker, Hans.
Application Number | 20020130131 10/100794 |
Document ID | / |
Family ID | 7678022 |
Filed Date | 2002-09-19 |
United States Patent
Application |
20020130131 |
Kind Code |
A1 |
Zucker, Hans ; et
al. |
September 19, 2002 |
Thermal container
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.
Inventors: |
Zucker, Hans; (Berlin,
DE) ; Sommer, Werner; (Berlin, DE) ; Worf,
Matthias; (Luebben/Spreewald, DE) |
Correspondence
Address: |
Law Offices of Karl Hormann
P.O. Box 381516
Cambridge
MA
02238-1516
US
|
Family ID: |
7678022 |
Appl. No.: |
10/100794 |
Filed: |
March 19, 2002 |
Current U.S.
Class: |
220/592.2 |
Current CPC
Class: |
F25D 2201/1282 20130101;
F17C 13/001 20130101; F25D 3/06 20130101; F17C 3/06 20130101; F25D
3/00 20130101; B65D 81/3806 20130101; F25D 2201/14 20130101; F17C
2203/0391 20130101; F25D 2331/804 20130101; F17C 3/04 20130101;
B65D 81/18 20130101; F17C 3/08 20130101 |
Class at
Publication: |
220/592.2 |
International
Class: |
B65D 081/38; B65D
083/72 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 19, 2001 |
DE |
101 13 183.6 |
Sep 25, 2001 |
DE |
101 48 586.7 |
Sep 27, 2001 |
DE |
101 48 587.5 |
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.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] 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.
[0003] 2. The Prior Art
[0004] 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.RTM., 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
[0005] 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.
[0006] 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.degree. C. to
-75.degree. C. in excess of 50 and preferably more than 100
hours.
[0007] 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.
[0008] It is a further object of the invention to provide a light
weight thermal container which is simple to manufacture.
[0009] 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.
[0010] 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
[0011] 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
.gtoreq.140 hours.
[0012] In accordance with the invention the combination of
individual insulating components is based upon the complementing
use of
[0013] high vacuum super insulation in outer shells, including
spacers and metalized reflexive foil having a heat transfer
coefficient of about 0.1 mW/mK;
[0014] dimensionally stable foam insulation including reinforced
margins and having a heat transfer coefficient of about 10
mW/mK;
[0015] high vacuum super insulation in cavities with supporting
structure and a heat transfer coefficient of 0.1 mW/mK;
[0016] reflection materials between the inner and outer walls of
the high vacuum super insulation;
[0017] 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;
[0018] known gettering techniques in the evacuated interior chamber
and dispensing of the getter material from appropriate devices;
[0019] 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
[0020] alternative foil vacuum insulations (vacuum insulation
panels) as highly effective heat shields with a heat transfer
coefficient of about 4 mW/mk.
[0021] 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.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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,.
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] 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.
[0044] 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,
[0045] biological materials in general, for instance living cell
cultures, at 37.degree. C.;
[0046] classic storage of thrombocytes at about 22.degree. C.;
[0047] whole blood at about 4.degree. C.;
[0048] blood plasma at about -40.degree. C.;
[0049] cell cultures, umbilical blood, skin, and others at
-90.degree. C. to -75.degree. C.
[0050] The container in accordance with the invention is also
suitable for operation in other temperature ranges.
[0051] 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.degree.
C. and -75.degree. 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
[0052] 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:
[0053] FIG. 1 is a view in axial section of a thermal transport
container in accordance with the invention;
[0054] FIG. 2 is a view in partial section of an external tube;
[0055] FIG. 3 is a view in partial section of an internal tube;
[0056] FIG. 4 is a view in partial section of a rim portion of a
prior art container;
[0057] FIG. 5 is a view in partial section of a rim portion of a
container in accordance with the invention;
[0058] FIG. 6 is a view in partial section of a rim portion of one
embodiment of a thermal container in accordance with the
invention;
[0059] FIG. 7 is a view in partial section of a rim portion of
another embodiment of a thermal container in accordance with the
invention;
[0060] 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;
[0061] FIG. 9 is a view in axial section of two stacked thermal
containers in accordance with the invention;
[0062] FIG. 10 is a view in partial section of the bottom portion
of a thermal container without pedestal;
[0063] FIG. 11 is a schematic view in section of a lid including
insulation component for a thermal container in accordance with the
invention;
[0064] FIG. 12 is a schematic view in section of a pedestal
including insulation component for a thermal container in
accordance with the invention;
[0065] 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
[0066] 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.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
EXAMPLE 1
[0067] 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.degree. C.
[0068] FIG. 1 depicts a 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.degree. 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.
[0069] At their exterior, the 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.
[0070] The 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.
[0071] FIGS. 2 and 3 respectively depict partial sectional views of
an external wall or 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.
[0072] For a better explanation of the invention, FIG. 4 depicts
the rim section of a prior art container, including a lid 41, in
partial section.
[0073] The container rim portion shown in FIG. 4 consists of an
external wall 37 with an internal vessel 38 and an outer wall 39.
An insulating material 40, usually made of polyurethane,
Styropor.RTM., 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.
[0074] FIG. 5 is a partial view of the rim portion of a container
in accordance with the invention. An internal tube or 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.
[0075] The end of the 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.
[0076] The 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
.ltoreq.10.sup.-4 Pa 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.
[0077] The double-sine or S-shaped 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.
[0078] As mentioned supra, the thickness of the material of
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.
[0079] As shown in FIG. 5, the entire container rim section is
encased by the 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.
[0080] The 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.
[0081] The 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.
[0082] The 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.
[0083] The 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.
[0084] 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 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.degree. C. to -75.degree. C.
EXAMPLE 2
[0085] A 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.
[0086] Accordingly, instead of being S-shaped 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.
[0087] It will be understood that such different profiles at the
transition between the 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.
[0088] The cavity or 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.
[0089] In accordance with the invention, the elements of Examples 1
and 2 of configuring the transitional zone between internal tube 15
and external tube 33 and more particularly those relating to
securing the insulation flange 11 may be combined.
EXAMPLE 3
[0090] A 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.
[0091] An 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
[0092] A 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.
[0093] Three further examples shown in FIG. 8 depict variations of
the connections between 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
[0094] At the rim of the openings of the hollow body, a 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.
[0095] For reasons of structural stability, the 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
[0096] As shown in FIG. 10, at the lower end the 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.
[0097] A 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.
[0098] As described in Example 1, the applied supportive structure
is a cellular one. The 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.
[0099] The bottom of the 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.
[0100] The useful life of the high vacuum super insulation 13
evacuated to .ltoreq.10.sup.-4 Pa 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 .ltoreq.140 hours at temperatures of -90.degree. C.
to -75.degree. C. At or towards the end of the constant temperature
time, the thermal energy storage units may be exchanged or
recharged.
EXAMPLE 7
[0101] FIG. 11 depicts a lid 12 of a vessel or transport container
1 which is operable at different temperatures.
[0102] In this embodiment, the 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.
[0103] In accordance with the invention, the two 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.
[0104] In the interior of the insulating 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
[0105] FIG. 12 depicts a 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.
[0106] In principle, the structure of the insulating 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
[0107] FIG. 13 depicts a partial section of two 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.degree. C. to about
-75.degree. C. Other temperature ranges result in different
operating periods.
[0109] In accordance with the invention (but not shown in the
drawings), the external tube 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
[0110] The following description is not shown in any drawing.
[0111] An 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.
[0112] For closing the 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
[0113] In the embodiment shown in FIG. 14, the 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.
[0114] The multi-layered 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.
[0115] In accordance with the invention, a structure similar to the
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.
[0116] The use of such an insulating 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.
[0117] 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.
* * * * *