U.S. patent application number 16/069572 was filed with the patent office on 2019-01-17 for system allowing automatic extraction of cold gases in a freezer cabinet operating with a cryogenic fluid.
This patent application is currently assigned to L'Air Liquide, Societe Anonyme pour I'Etude et I'Exploitation des Procedes Georges Claude. The applicant listed for this patent is L'Air Liquide, Societe Anonyme pour I'Etude et I'Exploitation des Procedes Georges Claude. Invention is credited to Didier PATHIER, Christian REYMOND.
Application Number | 20190017738 16/069572 |
Document ID | / |
Family ID | 55806530 |
Filed Date | 2019-01-17 |
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United States Patent
Application |
20190017738 |
Kind Code |
A1 |
PATHIER; Didier ; et
al. |
January 17, 2019 |
SYSTEM ALLOWING AUTOMATIC EXTRACTION OF COLD GASES IN A FREEZER
CABINET OPERATING WITH A CRYOGENIC FLUID
Abstract
The invention relates to a cabinet used for freezing or storing
food, medical or biological products, using a cryogenic fluid as
cooling fluid, said cabinet being of the type that is: provided
with one or more convection fans located in the enclosure of the
cabinet and capable of moving the air inside the cabinet and thus
of contributing to the thermal exchange that occurs therein; and
provided with a system for extracting the gases formed in the
enclosure of the cabinet due to the vaporization of said cryogenic
fluid, said extraction system including an extraction tube
connecting to one wall of the cabinet and linking the enclosure to
the outside; characterized in that it includes a flap, located on
said wall, at the point where the extraction tube enters the
cabinet, and extending into the cabinet, the shape, position and
direction of said flap making it possible to divert all or part of
the turbulence created by the or said convection fans towards the
extraction tube.
Inventors: |
PATHIER; Didier; (Voisins Le
Bretonneux, FR) ; REYMOND; Christian; (Montmorency,
FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
L'Air Liquide, Societe Anonyme pour I'Etude et I'Exploitation des
Procedes Georges Claude |
Paris |
|
FR |
|
|
Assignee: |
L'Air Liquide, Societe Anonyme pour
I'Etude et I'Exploitation des Procedes Georges Claude
Paris
FR
|
Family ID: |
55806530 |
Appl. No.: |
16/069572 |
Filed: |
January 10, 2017 |
PCT Filed: |
January 10, 2017 |
PCT NO: |
PCT/FR2017/050050 |
371 Date: |
July 12, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25D 3/122 20130101;
F25D 17/045 20130101; F25D 3/102 20130101; F25D 17/005
20130101 |
International
Class: |
F25D 17/04 20060101
F25D017/04; F25D 3/10 20060101 F25D003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 13, 2016 |
FR |
1650248 |
Claims
1. (canceled)
2. A deep-freezing or storage cabinet for food, medical or
biological products using a cryogenic fluid as cooling liquid,
comprising: a cabinet with an enclosure; one or more convection
fans located in the enclosure and capable of agitating air inside
the cabinet and thus of contributing to the thermal exchange that
occurs therein; and a system for extracting gases formed in the
enclosure due to vaporization of said cryogenic liquid, said
extraction system including an extraction tube that is connected to
one wall of the cabinet and links the enclosure to the outside, the
extraction system including a flap that is located on said wall at
a point where the extraction tube enters the cabinet and that
extend into the cabinet, a shape, position and orientation of said
flap making it possible to divert, toward the extraction tube, all
or part of turbulence created by the one or more convection
fans.
3. The deep-freezing or storage cabinet of claim 1, wherein the
flap is in the form of a scoop.
4. The deep-freezing or storage cabinet of claim 1, wherein the
flap is in the form of a truncated cylinder.
5. The The deep-freezing or storage cabinet of claim 1, wherein the
flap is in the form of an elbow tube.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a .sctn. 371 of International PCT
Application PCT/FR2017/050050, filed Jan. 10, 2017, which claims
.sctn. 119(a) foreign priority to French patent application FR 1
650 248, filed Jan. 13, 2016.
BACKGROUND
Field of the Invention
[0002] The present invention relates to the field of cabinets used
for deep-freezing or storing food, medical or biological products,
using a cryogenic fluid as cooling liquid, and relates more
particularly to the gas extraction system which is fitted to such
cabinets and which is an important element.
Related Art
[0003] Indeed, when the cabinet is in operation, it is cooled by
injection of a cryogenic fluid such as liquid nitrogen or liquid
CO.sub.2 into the closed enclosure of the device, and this fluid is
the cold source and its transition from the liquid state to the
gaseous state is associated with expansion of the gas. This
liquefied gas vaporizes in the enclosure and must subsequently be
evacuated from the machine to outside the production facility.
[0004] To that end, use is frequently made of an extraction tube
(in the manner of a chimney) which connects the enclosure to the
outside of the building. The gas then escapes naturally from the
enclosure to the outside. The slight overpressure created in the
enclosure is sufficient to cause the gas to flow to the outside of
the enclosure.
[0005] In other cases, the gases are made to flow actively. In such
cases, active extraction (fan, turbine, etc.) is installed on the
tube and serves to draw the gases to the outside.
[0006] When the cabinet is new and functions correctly, the
above-mentioned system operates very well.
[0007] However, after a certain time, the operating conditions
deviate slightly from ideal operation. Indeed, it has been noted
that, over time, the seals of the door(s) of the cryogenic cabinets
become less effective since no material can withstand the very low
temperatures of cryogenic deep-freezers without ultimately becoming
rigid or brittle. They therefore allow a greater or lesser quantity
of gas to pass through, which can in extreme cases lead to anoxia
(lack of oxygen) or intoxication (carbon dioxide) in the personnel
present in the production facility.
[0008] In order to avoid this, sites are obliged to change the
seals very frequently which, in practice, does not always happen,
and cryogenic deep-freezer cabinets therefore operate with
imperfect seals.
[0009] When production facilities are adequately ventilated, this
small leakage of gas due to imperfect seals can be regarded as not
presenting a critical problem since the gas leaks are ventilated by
the ventilation of the facility, and the installation can operate
without risk.
[0010] However, when the ventilation of the production facility is
not adequate for evacuating this gas leak to the outside, two
solutions are frequently used: [0011] The first solution involves
installing a system for permanent heating of the seals so as to
avoid their temperature dropping too low such that they lose their
elastic properties. Thus, the seals remain flexible and leak-tight
for longer than when they are subjected to low temperatures. The
problem of leaks is then delayed without being eliminated, which is
sometimes satisfactory. However, the cost of this technique is
considerable. [0012] The second solution involves installing active
extraction (a fan in the extraction tube, see above), which serves
to create a reduced pressure inside the cryogenic enclosure. Thus,
the leaks occurring at the door seals will no longer translate into
an escape of gas into the production facility, but rather an
ingress of air into the deep-freezing enclosure. Thus, the
deep-freezer no longer allows gas to escape into the production
facility, and the small ingress of air into the apparatus in no way
disrupts the deep-freezing process, provided that this ingress of
air remains at a limited level.
[0013] Thus, in order to compensate for the imperfect seal of the
door seals, and to eliminate the associated problem of gas leakage,
active extraction is installed. This extraction consists of a fan
installed in the extraction tube, an electricity supply and a
control system which triggers operation when necessary. This whole
assembly has a considerable cost in the total cost of the
deep-freezing installation and, where possible, an installation
without active extraction will always be preferred by the
production site.
SUMMARY OF THE INVENTION
[0014] As will be seen in greater detail below, the present
invention has the object of proposing a technical solution which
aims to dispense with the problem of the door seals of cryogenic
cabinets, at negligible cost.
[0015] To that end, the invention proposes using the fans that are
in any case present in deep-freezing cabinets (the primary function
of these fans is to agitate the air in the cabinet and thus
contribute to the thermal exchange that occurs therein) such that
they continue to perform this primary function but such that they
also perform a function of active extraction of the gases to the
outside.
[0016] The proposed solution comprises a flap (the cost of this
flap being negligible) which is located at the inlet of the
extraction tube in the deep-freezing cabinet, this flap extending
toward the interior of the cabinet and the shape, position and
orientation of the flap making it possible to take advantage of the
turbulence created by the fans. When the fans are running, the
turbulence created is redirected in part by the flap toward the
extraction tube, thus pushing the gases toward the outside of the
enclosure and thus creating a reduced pressure inside the
deep-freezing enclosure.
[0017] The shape and orientation of this flap will be chosen
depending on the type of fan used in the cabinet and their
direction (clockwise or counterclockwise) of operation.
[0018] Moreover, this flap must be studied so as to present minimum
disruption to the deep-freezing process of the cabinet (studied for
example by modelling or simply by testing on a real cabinet), in
particular in order to verify that the flap provides the desired
effect, which is to establish a reduced pressure within the
cabinet, that the flap does not excessively disrupt the flow of air
in the cell, and that it does not impair the coefficient of thermal
transfer in the deep-freezing cabinet.
BRIEF DESCRIPTION OF THE FIGURES
[0019] The appended figures show four exemplary embodiments of
these flaps, depending on whether the extraction is located at the
bottom or at the top of the deep-freezing cabinet, and depending on
whether the fans rotate in the clockwise or counterclockwise
direction.
[0020] appended FIG. 1 shows (in the left-hand view, extraction
tube not equipped with a flap) that the turbulence created by the
fans passes in front of the inlet to the extraction tube (located
in the lower portion of the cabinet) whereas, with the aid of the
flap positioned at the inlet to the extraction tube towards the
interior of the deep-freezing cabinet (middle view), at least part
of the turbulence enters the inlet of the extraction tube
(right-hand view). In this case, the flap is in the form of a
"folder" or "scoop".
[0021] appended FIG. 2 shows (in the left-hand view, extraction
tube not equipped with a flap) that, here too, the turbulence
created by the fans passes in front of the inlet to the extraction
tube and, with the aid of the flap positioned at the inlet to the
extraction tube towards the interior of the deep-freezing cabinet
(middle view), at least part of the turbulence enters the inlet of
the extraction tube (right-hand view). In this case too, the flap
is in the form of a "folder" or "scoop".
[0022] appended FIG. 3 shows a situation of clockwise operation of
the fans, and in which the extraction is located at the top of the
deep-freezing cabinet. Here too, by virtue of the flap positioned
at the inlet to the extraction tube towards the interior of the
deep-freezing cabinet (middle view), at least part of the
turbulence enters the inlet of the extraction tube (right-hand
view). In this case, the flap is in the form of a truncated
cylinder.
[0023] and appended FIG. 4 shows a situation of counterclockwise
operation of the fans, and in which the extraction is again located
at the top of the deep-freezing cabinet. Here too, by virtue of the
flap positioned at the inlet to the extraction tube towards the
interior of the deep-freezing cabinet (middle view), at least part
of the turbulence enters the inlet of the extraction tube
(right-hand view). In this case, the flap is in the form of an
"elbow tube".
[0024] It is clear that the forms of the flaps illustrated here are
only illustrative examples of the invention, and it will be
possible to use other forms but also to invert the forms in the
cases mentioned above (it will for example be possible to use an
elbow tube in the configuration of FIG. 1).
DETAILED DESCRIPTION OF THE INVENTION
[0025] Thus, the invention relates to a cabinet used for
deep-freezing or storing food, medical or biological products,
using a cryogenic fluid as cooling liquid, said cabinet being of
the type that is: [0026] provided with one or more convection fans
located in the enclosure of the cabinet and capable of agitating
the air inside the cabinet and thus of contributing to the thermal
exchange that occurs therein; [0027] and provided with a system for
extracting the gases formed in the enclosure of the cabinet due to
the vaporization of said cryogenic liquid, said extraction system
including an extraction tube that is connected to one wall of the
cabinet and links the enclosure to the outside;
[0028] characterized in that it includes a flap, located on said
wall, at the point where the extraction tube enters the cabinet,
and extending into the cabinet, the shape, position and orientation
of said flap making it possible to divert, toward the extraction
tube, all or part of the turbulence created by the or said
convection fans.
[0029] Tests carried out with a system in accordance with one of
the examples mentioned above have demonstrated excellent results:
[0030] the reduced pressure created in the enclosure can be
adjusted by changing the speed of the fans, and can reach 200 Pa (2
mbar). [0031] this device acts similar to an active extractor (fan
installed in the extraction conduit) such as implemented according
to the prior art, but with no active fan and without the associated
cost (the cost of the flap implemented here is entirely
negligible). [0032] in practice, this permits entirely safe
operation whatever the situation, with imperfect door seals and
with no leakage of gas into the production facility. [0033] the
deep-freezing process is not disrupted. [0034] this system is
suitable for deep-freezing cabinets operating with liquid nitrogen
or liquid CO.sub.2. It will be particularly useful for applications
operating with CO.sub.2 since, in this case, even small gas leaks
often have a large impact on the production floor and are rarely
tolerable.
[0035] While the invention has been described in conjunction with
specific embodiments thereof, it is evident that many alternatives,
modifications, and variations will be apparent to those skilled in
the art in light of the foregoing description. Accordingly, it is
intended to embrace all such alternatives, modifications, and
variations as fall within the spirit and broad scope of the
appended claims. The present invention may suitably comprise,
consist or consist essentially of the elements disclosed and may be
practiced in the absence of an element not disclosed. Furthermore,
if there is language referring to order, such as first and second,
it should be understood in an exemplary sense and not in a limiting
sense. For example, it can be recognized by those skilled in the
art that certain steps can be combined into a single step.
[0036] The singular forms "a", an and "the" include plural
referents, unless the context dearly dictates otherwise.
[0037] "Comprising" in a claim is an open transitional term which
means the subsequently identified claim elements are a nonexclusive
listing i.e. anything else may be additionally included and remain
within the scope of "comprising." "Comprising" is defined herein as
necessarily encompassing the more limited transitional terms
"consisting essentially of" and "consisting of"; "comprising" may
therefore be replaced by "consisting essentially of" or "consisting
of" and remain within the expressly defined scope of
"comprising".
[0038] "Providing" in a claim is defined to mean furnishing,
supplying, making available, or preparing something. The step may
be performed by any actor in the absence of express language in the
claim to the contrary.
[0039] Optional or optionally means that the subsequently described
event or circumstances may or may not occur. The description
includes instances where the event or circumstance occurs and
instances where it does not occur.
[0040] Ranges may be expressed herein as from about one particular
value, and/or to about another particular value. When such a range
is expressed, it is to be understood that another embodiment is
from the one particular value and/or to the other particular value,
along with all combinations within said range.
[0041] All references identified herein are each hereby
incorporated by reference into this application in their
entireties, as well as for the specific information for which each
is cited.
* * * * *