Technical field of the present invention
[0001] The present invention relates to an apparatus for reducing a temperature of at least
one item, in particular of at least one food item; more specifically, the present
invention relates to a high turbulence cooling apparatus.
[0002] The present invention further relates to a method of reducing a temperature of at
least one item, in particular of at least one food item.
Technological background of the present invention
[0003] Cryogenic food cooling/freezing apparatus, such as freezing tunnels, have limited
capacity based on the heat transfer coefficient of the apparatus. For example, a majority
of conventional food freezing tunnels increase heat transfer by increasing air flow
velocities. There are, however, practical and economical limitations to this method
of increasing heat transfer.
[0004] What is needed is apparatus and/or methods which allow for increases in overall heat
transfer of a cooling/freezing apparatus. Overall heat transfer increases may allow
for fabrication of smaller systems to achieve a desired throughput, or greater throughput
in conventionally-sized systems. An area of interest for increasing overall convective
heat transfer is through generation of turbulence within the cooling zone of a cooling/freezing
apparatus.
Disclosure of the present invention: object, solution, advantages
[0005] Starting from the disadvantages and shortcomings as described above as well as taking
the prior art as discussed into account, an object of the present invention is to
overcome the limitations and problems that earlier apparatus and methods have experienced.
[0006] This object is accomplished by an apparatus comprising the features of claim 1 as
well as by a method comprising the features of claim 13. Advantageous embodiments,
expedient improvements and other optional features of the present invention are set
forth herein and disclosed in the respective dependent claims.
[0007] The present invention basically provides for an apparatus, such as a freezing apparatus
or a freezing tunnel, for reducing a temperature (such as cooling or freezing) of
items, such as food items, comprising: a housing comprising a ceiling, a floor and
side walls defining a chamber within the housing; at least one conveyor extending
into the chamber between the ceiling and the floor; at least one gas circulation device
disposed in the chamber; and at least one turbulence-generating device disposed in
the chamber and between the at least one conveyor and the at least one gas circulation
device.
[0008] Also provided is a method of reducing a temperature of at least one item (such as
at least one food item) using a cooling apparatus (such as a freezing apparatus or
a freezing tunnel), including (for example comprising) at least one gas circulation
device for generating a flow of circulating gas in a flow path toward at least one
conveyor, comprising: providing at least one turbulence-generating device disposed
in the flow path between the at least one conveyor and the at least one gas circulation
device for disrupting the flow of the circulating gas at the flow path.
[0009] In certain embodiments, the method may further comprise moving the at least one turbulence-generating
device relative to movement of the at least one conveyor.
[0010] In certain embodiments, the circulating gas may comprise a cryogenic substance.
[0011] The at least one turbulence-generating device creates a turbulent heat transfer zone
through which the items are transported via the conveyor. Items entering a cooling
apparatus have a boundary layer of air surrounding them, which insulates the item
from a surrounding environment. Generation of turbulent flow around the items reduces
the boundary layer, allowing for increased heat transfer from the items to the surrounding
environment.
[0012] In certain embodiments, heat transfer may be increased by up to about thirty percent
as compared with conventional cooling/freezing apparatus.
[0013] In certain embodiments, the at least one turbulence-generating device may comprise
at least one elongated member disposed to disrupt gas circulation within the chamber.
[0014] In certain embodiments, the at least one turbulence-generating device may comprise
at least one cylindrical member, such as a cylindrical member capable of generating
vortex shedding.
[0015] For example, an array of cylindrical members, such as tubes or stainless steel tubes,
may be situated between a gas circulation device and a conveyor, within the flow path
generated by the gas circulation device. As gas passes around the cylindrical members
and/or through the array, vortices are created along the trailing edges of the cylindrical
members.
[0016] The vortices between the cylindrical members interact and shed as they impinge onto
the surface of the items to be cooled/frozen.
[0017] The diameter of the tubes, spacing between the tubes, and distance from the bottom
of the cylindrical member surface to the items to be cooled/frozen may be optimized
to provide a desired flow turbulence via routine experimentation in a particular application.
[0018] In certain embodiments, a long axis of each member of the array of cylindrical members
may be perpendicular to a long axis or path of travel of the conveyor.
[0019] In certain embodiments, depending on the particular application, the at least one
turbulence-generating device may be co-extensive with the entire flow path between
the at least one gas circulation device and the at least one conveyor, or may occupy
only a portion of such flow path.
[0020] In certain embodiments, depending on the particular application, the at least one
turbulence-generating device may be co-extensive with the width of the conveyor.
[0021] In certain embodiments, a plurality of turbulence generating devices may be positioned,
such as in an offset manner, above/below one another in the direction of flow within
the apparatus, such as in order to generate further increases in turbulence.
[0022] In certain embodiments, the at least one turbulence-generating device may be adapted
for oscillation within the flow path, in order to further increase turbulence generated
by the turbulence-generating device. For example, an array of cylindrical members
may be oscillated in a direction perpendicular to a long axis of each member of the
array of cylindrical members, such as in directions parallel and counter to the axis
of travel of the conveyor, in order to allow for further interaction of the vortices
created by the cylindrical members.
[0023] In certain embodiments, such as those in which the at least one turbulence-generating
device comprises at least one tube, one or more of the at least one tube may be adapted
for injection or spraying of a coolant and/or cryogen, such as liquid nitrogen and/or
solid/liquid/gaseous carbon dioxide, into the chamber of the cooling/freezing apparatus,
toward the items. This may allow for even higher heat transfer coefficients.
[0024] The term "cryogen" as used herein is similar to the term "coolant", and is not intended
to necessarily be limited to materials which have a purely cryogenic effect, although
that meaning is intended to be included in the use of "cryogen".
[0025] The term "coolant" as used herein means any material which provides a cooling effect
to or reduces a temperature of an item.
[0026] In certain embodiments, the cooling/freezing apparatus may comprise a shroud or baffle
being arranged for coaction with the at least one gas circulation device.
[0027] In certain embodiments, the at least one shroud or baffle may direct the flow of
the circulating gas to be forced through the at least one turbulence-generating device
toward the at least one item on the at least one conveyor.
[0028] In certain embodiments, the at least one shroud or baffle may enclose the at least
one gas circulation device so that the circulating gas may be forced through the at
least one turbulence-generating device.
[0029] In certain embodiments, the at least one shroud or baffle may be constructe as at
least one longitudinal member extending within the chamber from the at least one turbulence-generating
device to close proximity of an inlet of the at least one gas circulation device for
directing the flow of the circulating gas to said inlet.
[0030] During operation of a cooling/freezing apparatus as described herein, snow and/or
ice may build up on the surface(s) of the at least one turbulence-generating device.
A manual or automatic cleaning system may be incorporated into the cooling/freezing
apparatus in order to periodically remove snow and/or ice from the at least one turbulence-generating
device.
[0031] For example, in embodiments in which the at least one turbulence-generating device
comprises an array of cylindrical members, a scraping device may be installed which
scrapes the cylindrical members using a plate with half-round shapes. The plate may
be permanently or temporarily engaged with an extending member to permit travel along
the length of the array of cylindrical members.
[0032] In these embodiments, snow and/or ice may preferentially accumulate on the surface
of the cylindrical members which faces opposite the direction of gas flow, and therefore
the half-round shapes may be sufficient to remove most, if not all, of snow and/or
ice accumulated on the cylindrical members.
Brief description of the drawings
[0033] For a more complete understanding of the present embodiment disclosures and as already
discussed above, there are several options to embody as well as to improve the teaching
of the present invention in an advantageous manner. To this aim, reference may be
made to the claims dependent on claim 1 as well as on claim 13; further improvements,
features and advantages of the present invention are explained below in more detail
with reference to particular and preferred embodiments by way of non-limiting example
and to the appended drawing figures taken in conjunction with the following description
of exemplary embodiments, of which:
- FIG. 1
- is a cross-sectional view of a first embodiment of a cooling/freezing apparatus as
described herein, said apparatus working according to the method of the present invention;
- FIG. 2
- is a cross-sectional view of a second embodiment of a cooling/freezing apparatus as
described herein, said apparatus working according to the method of the present invention;
- FIG. 3
- is a cross-sectional view of a first embodiment of a turbulence-generating device
as described herein;
- FIG. 4
- is a cross-sectional view of a second embodiment of a turbulence-generating device
as described herein; and
- FIG. 5
- is a cross-sectional view of a third embodiment of a turbulence-generating device
as described herein.
[0034] The accompanying drawings are included to provide a further understanding of the
apparatus and method(s) provided herein and are incorporated in and constitute a part
of this specification. The drawings illustrate embodiments of the apparatus and method(s)
provided herein and, together with the description, serve to explain the principles
described herein but are not intended to limit the specification or any of the claims.
In the accompanying drawings, like equipment is labelled with the same reference numerals
throughout the description of FIG. 1 to FIG. 5.
Detailed description of the drawings;
best way of embodying the present invention
[0035] Before explaining the present inventive embodiment in detail, it is to be understood
that the embodiment is not limited in its application to the details of construction
and arrangement of parts illustrated in the accompanying drawing, since the present
invention is capable of other embodiments and of being practiced or carried out in
various ways. Also, it is to be understood that the phraseology or terminology employed
herein is for the purpose of description and not of limitation.
[0036] In the following description, terms such a horizontal, upright, vertical, above,
below, beneath and the like, are used solely for the purpose of clarity illustrating
the present invention and should not be taken as words of limitation. The drawings
are for the purpose of illustrating the present invention and are not intended to
be to scale.
[0037] In particular and referring to FIG. 1, there is shown an illustrative apparatus 10,
such as a freezing apparatus or tunnel, for cooling or freezing items 12, such as
food items, having a housing 14 with a ceiling 16, a floor 18 and side walls 20, which
define a chamber 22 within the housing 14.
[0038] A conveyor 24 extends into the chamber 22 between the ceiling 16 and the floor 18.
A gas circulation device 26 (such as an axial flow fan, as depicted in FIG. 1) in
mechanical communication with a motor 28, is disposed in the chamber 22, and generates
the flow of the circulating gas 30.
[0039] A turbulence-generating device 32 is disposed in the chamber 22 in the flow path
between the gas circulation device 26 and the conveyor 24. An optional shroud 34 encloses
the gas circulation device 26 so that the circulating gas 30 is forced through the
turbulence-generating device 32 toward the items 12 on the conveyor 24.
[0040] In particular and referring to FIG. 2, there is shown an illustrative apparatus 50,
such as a freezing apparatus or tunnel, for cooling or freezing items 12, such as
food items, having a housing 54 with a ceiling 56, a floor 58 and side walls 60, which
define a chamber 62 within the housing 54.
[0041] A conveyor 24 extends into the chamber 62 between the ceiling 56 and the floor 58.
A gas circulation device 66 (such as an centrifugal blower, as depicted in FIG. 2)
in mechanical communication with a motor 68, is disposed in the chamber 62, and generates
the flow of the circulating gas 30.
[0042] A turbulence-generating device 32 is disposed in the chamber 62 in the flow path
between the gas circulation device 66 and the conveyor 24. An optional shroud or baffle
74 constructed and arranged for coaction with the gas circulation device 66 directs
the flow of the circulating gas 30 to be forced through the turbulence-generating
device 32 toward the items 12 on the conveyor 24.
[0043] The shroud 74 can be constructed as a longitudinal member extending within the chamber
62 from the turbulence-generating device 32 to close proximity of an inlet of the
gas circulation device 66 for directing the flow of the circulating gas 30 to said
inlet.
[0044] In particular and referring to FIG. 3 through FIG. 5, there is shown the illustrative
turbulence-generating device(s) 32 comprising an array of cylindrical members 78 (such
as tubes), constructed of a material which may be suitable for use in the apparatus
of FIG. 1 and/or FIG. 2.
[0045] The cylindrical members 78 generate turbulent gas flow 80 when the circulating gas
30 passes between and around the cylindrical members 78. The cylindrical members 78
generate vortex shedding 86, and the vortices may interact with each other in order
to further increase the turbulence of the turbulent gas flow 80.
[0046] The turbulent gas flow 80 reduces a boundary layer around each item 12 being transported
on the conveyor 24, thereby allowing for increased heat transfer from the items 12
to the circulating gases 30, 80.
[0047] FIG. 4 depicts an alternative embodiment of the turbulence-generating device 32,
in which the cylindrical members 78 may be oscillated, such as in parallel with and
counter to the axis of travel of the conveyor 24, as represented by arrows 82.
[0048] FIG. 5 depicts an alternative embodiment of the turbulence-generating device 32,
in which one or more of the cylindrical members 78 may be adapted with outlets and/or
nozzles for injecting/spraying 84 cryogen into the turbulent gas flow 80 and toward
the items 12 on the conveyor 24 for heat transfer.
[0049] In certain embodiments, the cryogen may be liquid nitrogen (LIN) and/or solid/liquid/gaseous
carbon dioxide.
[0050] It will be understood that the embodiments described herein are merely exemplary,
and that one skilled in the art may make variations and modifications without departing
from the spirit and scope of the present invention. All such variations and modifications
are intended to be included within the scope of the present invention as described
and claimed herein. Further, all embodiments disclosed are not necessarily in the
alternative, as various embodiments of the present invention may be combined to provide
the desired result.
List of reference signs
[0051]
- 10
- apparatus, in particular cooling apparatus or freezing apparatus, in particular freezing
tunnel
- 12
- item, in particular food item
- 14
- housing
- 16
- ceiling
- 18
- floor
- 20
- side wall
- 22
- chamber
- 24
- conveyor
- 26
- gas circulation device, in particular axial flow fan
- 28
- motor
- 30
- circulating gas
- 32
- turbulence-generating device, in particular elongated member
- 34
- shroud
- 50
- apparatus, in particular cooling apparatus or freezing apparatus, in particular freezing
tunnel
- 54
- housing
- 56
- ceiling
- 58
- floor
- 60
- side wall
- 62
- chamber
- 66
- gas circulation device, in particular centrifugal blower
- 68
- motor
- 74
- shroud or baffle, in particular longitudinal member
- 78
- cylindrical member, in particular tube, for example stainless steel tube
- 80
- turbulent gas flow
- 82
- direction of axis of travel of conveyor 24
- 84
- cryogen injection or cryogen spray
- 86
- vortex shedding
1. An apparatus (10; 50) for reducing a temperature of at least one item (12), in particular
of at least one food item, comprising:
- a housing (14; 54) comprising a ceiling (16; 56), a floor (18, 58) and side walls
(20; 60) defining a chamber (22; 62) within the housing (14; 54);
- at least one conveyor (24) extending into the chamber (22; 62) between the ceiling
(16; 56) and the floor (18, 58);
- at least one gas circulation device (26; 66) disposed in the chamber (22; 62); and
- at least one turbulence-generating device (32) disposed in the chamber (22; 62)
and between the at least one conveyor (24) and the at least one gas circulation device
(26; 66).
2. The apparatus according to claim 1, wherein the at least one gas circulation device
(26; 66) generates the flow of circulating gas (30).
3. The apparatus according to claim 2, wherein the at least one turbulence-generating
device (32) comprises at least one elongated member disposed to disrupt the flow of
the circulating gas (30) within the chamber (22; 62).
4. The apparatus according to claim 2 and to claim 1 or 3, wherein the at least one turbulence-generating
device (32) comprises at least one cylindrical member (78), in particular an array
of cylindrical members (78), for generating turbulent gas flow (80) when the circulating
gas (30) passes between and/or around the at least one cylindrical member (78).
5. The apparatus according to claim 4, wherein the at least one cylindrical member (78)
generates vortex shedding (86).
6. The apparatus according to claim 5, wherein the vortices interact with each other
in order to further increase the turbulence of the turbulent gas flow (80), said turbulent
gas flow (80) reducing a boundary layer around the at least one item (12) being transported
on the at least one conveyor (24), thereby allowing for increased heat transfer from
the at least one item (12) to the circulating gas (30) and/or to the turbulent gas
flow (80).
7. The apparatus according to at least one of claims 4 to 6, wherein the at least one
cylindrical member (78) is oscillated, in particular in parallel with and counter
to the direction (82) of the axis of travel of the at least one conveyor (24).
8. The apparatus according to at least one of claims 4 to 7, wherein the at least one
cylindrical member (78) is provided with at least one outlet and/or nozzle for injecting/spraying
(84) a coolant or a cryogenic substance, in particular liquid nitrogen and/or solid/liquid/gaseous
carbon dioxide, into the turbulent gas flow (80) and toward the at least one item
(12) on the at least one conveyor (24) for heat transfer.
9. The apparatus according to at least one of claims 1 to 8, wherein at least one shroud
or baffle (34; 74) is arranged for coaction with the at least one gas circulation
device (26; 66).
10. The apparatus according to claim 2 and 9, wherein the at least one shroud or baffle
(34; 74) directs the flow of the circulating gas (30) to be forced through the at
least one turbulence-generating device (32) toward the at least one item (12) on the
at least one conveyor (24).
11. The apparatus according to claim 9 or 10, wherein the at least one shroud or baffle
(34) encloses the at least one gas circulation device (26).
12. The apparatus according to claim 2 and to at least one of claims 9 to 11, wherein
the at least one shroud or baffle (74) is constructed as at least one longitudinal
member extending within the chamber (62) from the at least one turbulence-generating
device (32) to close proximity of an inlet of the at least one gas circulation device
(66) for directing the flow of the circulating gas (30) to said inlet.
13. A method of reducing a temperature of at least one item (12), in particular of at
least one food item, using a cooling apparatus (10; 50), including at least one gas
circulation device (26; 66) for generating a flow of circulating gas (30) in a flow
path toward at least one conveyor (24), comprising:
providing at least one turbulence-generating device (32) disposed in the flow path
between the at least one conveyor (24) and the at least one gas circulation device
(26; 66) for disrupting the flow of the circulating gas (30) at the flow path.
14. The method according to claim 13, further comprising moving the at least one turbulence-generating
device (32) relative to movement of the at least one conveyor (24).
15. The method according to claim 13 or 14, wherein the circulating gas (30) comprises
a coolant or a cryogenic substance, in particular liquid nitrogen and/or solid/liquid/gaseous
carbon dioxide.