U.S. patent application number 13/871759 was filed with the patent office on 2013-10-31 for apparatus and method for chilling or freezing objects utilizing a rotary drum having prominences formed on an inner surface thereof.
This patent application is currently assigned to Air Liquide Industrial U.S. LP. The applicant listed for this patent is AIR LIQUIDE INDUSTRIAL U.S. LP. Invention is credited to David C. BRAITHWAITE, Angela A. Doray Chang, Ronald C. Idol.
Application Number | 20130283828 13/871759 |
Document ID | / |
Family ID | 49476142 |
Filed Date | 2013-10-31 |
United States Patent
Application |
20130283828 |
Kind Code |
A1 |
BRAITHWAITE; David C. ; et
al. |
October 31, 2013 |
Apparatus and Method for Chilling or Freezing Objects Utilizing a
Rotary Drum Having Prominences Formed on an Inner Surface
Thereof
Abstract
In an apparatus and method for chilling or freezing objects, an
interior surface of a rotating drum includes recesses formed
between prominences extending inwardly from the interior surface.
One or more liquid CO.sub.2 nozzles inject solid CO.sub.2 towards
the interior surface. The injected snow replenishes a depth of
solid CO.sub.2 in empty or partially empty recesses and/or provides
a fresh layer of solid CO.sub.2 on top of the objects. Because the
interior surface is made of polyethylene and the depth of solid
CO.sub.2 is replenished in empty or partially empty recesses, the
product/drum sticking problem experienced by conventional
apparatuses and methods is reduced or avoided. Optionally, the
CO.sub.2 snow is injected into empty or partially empty recesses by
at least one first liquid CO.sub.2 nozzle and is deposited on top
of the objects by at least one second liquid CO.sub.2 nozzle so
that each opposing surface of the object is in direct contact with
solid CO.sub.2.
Inventors: |
BRAITHWAITE; David C.;
(Houston, TX) ; Idol; Ronald C.; (Cypress, TX)
; Doray Chang; Angela A.; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AIR LIQUIDE INDUSTRIAL U.S. LP |
Houston |
TX |
US |
|
|
Assignee: |
Air Liquide Industrial U.S.
LP
Houston
TX
|
Family ID: |
49476142 |
Appl. No.: |
13/871759 |
Filed: |
April 26, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61638800 |
Apr 26, 2012 |
|
|
|
Current U.S.
Class: |
62/62 ;
62/346 |
Current CPC
Class: |
F25D 3/12 20130101; F25D
3/127 20130101; A23B 4/062 20130101; F25D 2500/02 20130101; A23B
4/09 20130101 |
Class at
Publication: |
62/62 ;
62/346 |
International
Class: |
F25D 3/12 20060101
F25D003/12 |
Claims
1. An apparatus for chilling or freezing objects, the apparatus
comprising a rotatable drum defining an enclosure having an
interior surface, an inlet at one end of the drum, an outlet at an
opposing end of the drum, one or more liquid CO.sub.2 nozzles
disposed in an interior of the drum each one of which is adapted to
inject a stream of solid CO.sub.2 into the enclosure towards the
interior surface, wherein: the interior surface of the drum is
comprised of polyethylene having prominences molded into the
polyethylene; portions of the interior surface in between
prominences form recesses relative to the prominences that are
adapted and configured to retain a depth of solid CO.sub.2; and the
prominences are not directional vanes.
2. The apparatus of claim 1, wherein: said at least two liquid
CO.sub.2 nozzles comprise at least one first liquid CO.sub.2 nozzle
and at least one second liquid CO.sub.2; each of said at least one
first liquid CO.sub.2 nozzles being disposed in an interior of the
drum and being adapted, configured, and oriented to provide a first
stream of solid CO.sub.2 towards a first angular position on the
inner surface; each of said at least one second liquid CO.sub.2
nozzle being disposed in the drum interior and being adapted,
configured, and oriented to provide a second stream of solid
CO.sub.2 towards a second angular position on the inner surface;
and the first angular position is between 70-110.degree. and/or
250-290.degree. with respect to vertical and the second angular
position is between 160-200.degree. with respect to vertical.
3. The apparatus of claim 1, further comprising directional vanes
on the interior surface.
4. The apparatus of claim 1, wherein the prominences extend
approximately 0.25 to 1 inches from the interior surface.
5. The apparatus of claim 4, further comprising directional vanes
on the interior surface.
6. A method for chilling or freezing objects, comprising the steps
of: providing the apparatus of claim 1; rotating the drum;
introducing the objects into the interior the drum; and injecting a
stream of solid CO.sub.2 into the enclosure towards the interior
surface from one or more liquid CO.sub.2 nozzles, wherein the solid
CO.sub.2 is deposited in the recesses and/or on top of the objects;
and removing the objects from the outlet of the drum.
7. The method of claim 6, wherein: said at least two liquid
CO.sub.2 nozzles comprise at least one first liquid CO.sub.2 nozzle
and at least one second liquid CO.sub.2; each of said at least one
first liquid CO.sub.2 nozzles being disposed in an interior of the
drum and injects a first stream of solid CO.sub.2 towards a first
angular position on the inner surface; each of said at least one
second liquid CO.sub.2 nozzle being disposed in the drum interior
and injects a second stream of solid CO.sub.2 towards a second
angular position on the inner surface; and the first angular
position is between 70-110.degree. and/or 250-290.degree. with
respect to vertical and the second angular position is between
160-200.degree. with respect to vertical.
8. The method of claim 7, wherein the first stream(s) deposits a
fresh layer of solid CO.sub.2 in the recesses and the second
stream(s) deposits solid CO.sub.2 on top of the objects tumbling at
or adjacent to a bottom of the drum.
9. The method of claim 6, wherein the objects are food
products.
10. The method of claim 9, wherein the food products are meat
products.
Description
BACKGROUND
[0001] Many food products must be chilled below 40.degree. F. prior
to shipment. Sometimes this is achieved by mixing the product with
solid CO.sub.2 (either dry ice "snow" or dry ice pellets) in a
stainless steel drum. However, the interior surface of the
stainless steel drum becomes so cold that moist products can stick
to the surface, resulting in damaged product, un-recovered product,
and disruption of the flow of product through the drum.
[0002] To solve this problem, many prior art references utilize a
small amount of water that forms an ice layer on the stainless
steel surface. See, e.g., U.S. Pat. No. 5,220,812 to Palbiski et
al. and U.S. Pat. No. 5,603,567 to Peacock. Others position the
CO.sub.2 nozzles so that CO.sub.2 snow is only administered onto
the pieces of food being cooled. See, e.g., U.S. Pat. No. 6,497,106
to Lang et al. Either method fails to provide effective two-sided
exposure of the object to CO.sub.2 snow and thereby extends the
amount of time it takes to chill the product.
[0003] Thus, there is a need in the art for a method of cooling
food with solid CO.sub.2 in a rotating drum without incurring too
much product sticking.
SUMMARY
[0004] There is provided an apparatus for chilling or freezing
objects, the apparatus comprising a rotatable drum defining an
enclosure having an interior surface, an inlet at one end of the
drum, an outlet at an opposing end of the drum, and at least two
CO2 nozzles located within the enclosure, at least one CO2 nozzle
positioned horizontally and at least one CO2 nozzle positioned
vertically, the interior surface being polyethylene having
prominences thereon, wherein the prominences are not directional
vanes.
[0005] There is also provided a method for chilling or freezing
objects, the method comprising the following steps. The
above-provided apparatus is provided. CO.sub.2 snow is ejected from
the at least one CO.sub.2 nozzle positioned horizontally to produce
a blanket of CO.sub.2 snow on the interior surface between the
prominences. The object to be chilled or frozen is introduced into
the inlet of the drum. The drum is rotated. CO.sub.2 snow is
ejected from the at least one CO.sub.2 nozzle positioned vertically
to produce a blanket of CO.sub.2 snow on the object. The object is
removed from the outlet of the drum.
[0006] There is also provided another apparatus for chilling or
freezing objects, the apparatus comprising a rotatable drum
defining an enclosure having an interior surface, an inlet at one
end of the drum, an outlet at an opposing end of the drum, one or
more liquid CO.sub.2 nozzles disposed in an interior of the drum
each one of which is adapted to inject a stream of solid CO.sub.2
into the enclosure towards the interior surface. The interior
surface of the drum is comprised of polyethylene having prominences
molded into the polyethylene. Portions of the interior surface in
between prominences form recesses relative to the prominences that
are adapted and configured to retain a depth of solid CO.sub.2. The
prominences are not directional vanes.
[0007] There is also provided another method for chilling or
freezing objects, comprising the following steps. The above
apparatus is provided. The drum is rotated. The objects are
introduced into the interior the drum. A stream of solid CO.sub.2
is injected into the enclosure towards the interior surface from
one or more liquid CO.sub.2 nozzles, wherein the solid CO.sub.2 is
deposited in the recesses and/or on top of the objects. The objects
are removed from the outlet of the drum.
[0008] The apparatus or method may include any one or more of the
following aspects: [0009] the apparatus further comprises
directional vanes on the interior surface. [0010] the prominences
extend approximately 0.25 to 1 inches from the interior surface.
[0011] the apparatus further comprises directional vanes on the
interior surface. [0012] said at least two liquid CO.sub.2 nozzles
comprise at least one first liquid CO.sub.2 nozzle and at least one
second liquid CO.sub.2, each of said at least one first liquid
CO.sub.2 nozzles being disposed in an interior of the drum and
being adapted, configured, and oriented to provide a first stream
of solid CO.sub.2 towards a first angular position on the inner
surface, each of said at least one second liquid CO.sub.2 nozzle
being disposed in the drum interior and being adapted, configured,
and oriented to provide a second stream of solid CO.sub.2 towards a
second angular position on the inner surface, and the first angular
position is between 70-110.degree. and/or 250-290.degree. with
respect to vertical and the second angular position is between
160-200.degree. with respect to vertical. [0013] the apparatus
further comprises directional vanes on the interior surface. [0014]
the prominences extend approximately 0.25 to 1 inches from the
interior surface. [0015] the apparatus further comprises
directional vanes on the interior surface. [0016] said at least two
liquid CO.sub.2 nozzles comprise at least one first liquid CO.sub.2
nozzle and at least one second liquid CO.sub.2, each of said at
least one first liquid CO.sub.2 nozzles being disposed in an
interior of the drum and injects a first stream of solid CO.sub.2
towards a first angular position on the inner surface, each of said
at least one second liquid CO.sub.2 nozzle being disposed in the
drum interior and injects a second stream of solid CO.sub.2 towards
a second angular position on the inner surface, and the first
angular position is between 70-110.degree. and/or 250-290.degree.
with respect to vertical and the second angular position is between
160-200.degree. with respect to vertical. [0017] the first
stream(s) deposits a fresh layer of solid CO.sub.2 in the recesses
and the second stream(s) deposits solid CO.sub.2 on top of the
objects tumbling at or adjacent to a bottom of the drum. [0018] the
objects are food products. [0019] the food products are meat
products.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] For a further understanding of the nature and objects of the
present invention, reference should be made to the following
detailed description, taken in conjunction with the accompanying
drawings, in which like elements are given the same or analogous
reference numbers and wherein:
[0021] FIG. 1 is a cross-sectional, front (inlet) view of an
embodiment of the disclosed chilling or freezing apparatus taken
along an axis of the rotating drum that illustrates alternative
positions and orientations for the CO.sub.2 snow nozzles.
[0022] FIG. 2 is a side, elevation view of another embodiment of
the disclosed chilling or freezing apparatus that includes
directional vanes but which omits the prominences for the sake of
clarity;
[0023] FIG. 3 is an isometric, schematic view of the rotating drum
of the disclosed chilling or freezing apparatus;
[0024] FIG. 4 is an elevation side view of one embodiment of the
interior surface of the rotating drum;
[0025] FIG. 5 is an elevation side view of a second embodiment of
the interior surface of the rotating drum; and
[0026] FIG. 6 is an elevation side view of a third embodiment of
the interior surface of the rotating drum.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0027] Disclosed is an apparatus and method for chilling or
freezing objects. While the preferred embodiments are disclosed
with respect to food products, and preferably with respect to meat
products, such as chicken, beef, and turkey parts, the disclosed
apparatus and method may also be utilized with any object that
requires chilling or freezing, such as seafood, produce, golf ball
centers and insulated wire scrap.
[0028] In the inventive apparatus and method, an interior surface
of a rotating drum (forming an enclosure) includes recesses formed
between prominences that extend inwardly from the interior surface.
The recesses are adapted and configured to be filled or partially
filled with solid CO.sub.2 from one or more liquid CO.sub.2 nozzles
disposed within the enclosure that inject solid CO.sub.2 towards
the interior surface. In the event that solid CO.sub.2 is
sublimated or tumbles out of recesses in portions of the drum
rotating overhead, a depth of solid CO.sub.2 is replenished by
injection of the solid CO.sub.2 from the nozzle(s). Typically, the
solid CO.sub.2 is deposited into the empty or partially empty
recesses prior to that portion of the inner surface passing under
the objects tumbling inside the rotating drum. In this way, the
depth of solid CO.sub.2 in empty or partially empty recesses is
replenished and the objects to be cooled or frozen at most only
touch the innermost portions of the prominences. Thus, the problem
of product/drum sticking that is experienced by conventional
apparatuses and methods is reduced or avoided.
[0029] Alternatively, or in addition to the above-described solid
CO.sub.2 depth replenishment or partial replenishment, the
nozzle(s) may deposit a fresh layer of solid CO.sub.2 on top of the
objects tumbling at or adjacent to a bottom of the rotating drum.
When combined with the above-described CO.sub.2 depth replenishment
or partial replenishment, each of the opposing surfaces of the
objects are in direct contact with solid CO.sub.2 so that the
efficiency of the cryogenic cooling is enhanced in comparison to
conventional apparatuses and methods.
[0030] The solid CO.sub.2 that is deposited into empty or partially
empty recesses is injected by at least one first liquid CO.sub.2
nozzle and the solid CO.sub.2 that is deposited on top of the
objects is injected by at least one second liquid CO.sub.2 nozzle.
Each of the at least one first liquid CO.sub.2 nozzle is adapted,
configured and oriented to inject a first stream of solid CO.sub.2
towards a first angular position on the interior surface while each
of the at least one second liquid CO.sub.2 nozzle is adapted,
configured and oriented to inject a first stream of solid CO.sub.2
towards a second angular position on the interior surface. The
first angular position is generally around a one quarter revolution
of the drum from a top of the drum while the second angular
position is generally around a half revolution of the drum from a
top of the drum. Typically, the first angular position is between
50-130.degree. or 230-310.degree. (or in the case of two first
liquid CO2 nozzles at a same axial position of the drum, between
50-130.degree. and between 230-310.degree.) with respect to
vertical. Typically, the second angular position is between
140-220.degree. with respect to vertical. More typically, the first
angular position is between 80-120.degree. with respect to vertical
and the second angular position is between 160-200.degree. with
respect to vertical.
[0031] Solid CO.sub.2 has a significant latent heat of
vaporization. When heat is transferred from the object (to be
cooled or frozen) to the solid CO.sub.2, an amount of the solid
CO.sub.2 is sublimated. Solid CO.sub.2 at atmospheric pressure is
at a temperature of around -78.5.degree. C. When the objects to be
cooled or frozen are food products, the liquid CO.sub.2 injected
from the nozzle(s) is typically food-grade CO.sub.2.
[0032] The rotatable drum may have any shape that permits rotation,
including but not limited to cylindrical, a hexagonal prism (i.e.,
elongated hexagon), or an octagonal prism (i.e., elongated
octagon). Typically, it is cylindrical. The axis of the rotatable
drum is generally positioned more horizontal than vertical.
Typically, the drum axis is declined from the inlet towards the
outlet in order to move the objects from the inlet to the outlet by
the force of gravity. The interior surface of the rotatable drum is
polyethylene, typically food-grade polyethylene. Polyethylene
exhibits much less sticking between it and the objects to be cooled
in comparison to conventional drum materials such as stainless
steel.
[0033] The drum has prominences extending inwardly from the inner
surface. Recesses are formed between the prominences. Solid
CO.sub.2 injected by the one or nozzles fills or partially fills
these recesses with CO.sub.2 snow. In this manner, a portion of the
surface of the object adjacent the inner surface of the drum is in
contact with solid CO.sub.2 (filling or partially filling a recess)
instead of with the inner surface of the drum. In this manner, at
most only a portion of each object to be chilled or frozen is in
direct contact with one or more prominences. Thus, the problem of
sticking exhibited by conventional apparatuses and methods is
reduced or avoided. It should be noted that the inner surface of
the drum is continuous and not perforated, so that the solid
CO.sub.2 may not pass through the drum in the radial direction.
[0034] The particular shape of the prominences is not essential to
the invention so long as the prominences are sized and spaced to
form valleys that can be filled with CO.sub.2 snow to cool or
freeze objects extending across them or suspended on the
prominences. The desired shape of the prominences is typically
driven by the ease with which the shapes may be manufactured, such
as by molding, and/or is driven by the shape and size of the object
to be cooled or frozen. While the shapes of each of the prominences
need not be uniform, typically they are. Similarly, while the
spaces in between the prominences need not be uniform, typically
they are.
[0035] By way of a non-limiting example, in the case of meat
products to be chilled or frozen, the heights of the prominences
typically extend approximately 0.25 inches to approximately 1 inch
from the interior surface of the drum. However, one of ordinary
skill in the art will recognize that for larger or smaller objects,
the heights of the prominences may respectively extend a longer or
shorter distance from the interior surface. One of ordinary skill
in the art will of course recognize that the depth of a particular
recess will equal the height of an adjacent prominence. Thus, for
prominences having heights of 0.25 inches or 1 inch, the
corresponding recesses have depths of 0.25 inches or 1 inch,
respectively. Consequently, the solid CO.sub.2 filling the recess
in the foregoing example will have a fill depth of 0.25 inches to 1
inch.
[0036] The prominences may be cylindrically shaped so that each
portion of a planar, circular top surface of the prominence extends
a same height from the interior surface of the drum. Alternatively,
the prominences may be hemispherically shaped so that the height of
the prominence is at a minimum at its outer circumference and is at
a maximum in the center of the prominence. While an outer edge of
each cylindrical or hemispherical projection is typically located
approximately 0.25 inches to 2.00 inches from the outer edges of
adjacent cylindrical or hemispherical prominences, this
prominence-to-prominence spacing distance may be greater or smaller
depending upon the size of the object to be chilled or cooled.
[0037] The cross-sectional shape of the prominences (taken along a
height of the prominences) may take include: crescent moons,
semicircles, ovals, rectangles, parallelograms, trapezoids,
crosses, triangles, squares, pentagons, hexagons, heptagons,
octagons, and the like. Combinations of these shapes may also be
used.
[0038] The prominences may also be shaped as parallel ridges. The
heights of the ridges and the spacing in between adjacent ridges
are not limited and may be varied upon the size and shape of the
object to be cooled or frozen. The parallel ridges may be oriented
parallel to the axis of the drum, perpendicular to the axis of the
drum, or angled to the axis of the drum. Alternatively, the
parallel ridges may be oriented such that they form spirals with an
axis of the spiral being the axis of the drum. In this way, the
spiral-oriented parallel ridges form "rifling" that helps move the
object (to be chilled or frozen) along the axis of the drum from
the inlet to the outlet.
[0039] The prominences are not directional vanes, but instead are
positioned to suspend the object away from the interior surface.
Directional vanes are commonly used in rotatable drums to direct
the object from the inlet to the outlet during rotation.
Directional vanes can further be distinguished from the prominences
of the invention by the fact that directional vanes have a height
dimension (in the radial direction extending inward towards the
axis of the drum) that is at least three times greater than its
width dimension, while the prominences of the invention do not.
Because the directional vanes have such a high aspect ratio (height
to width), they are very poorly suited to contain a depth of solid
CO.sub.2 in between the vanes. In other words, the relatively high
height of the vanes results in a relatively great depth of solid
CO.sub.2 that may tend to accumulate in between the vanes. The
relatively greater depth and corresponding mass of solid CO.sub.2
will greatly increase the energy needed to rotate the drum.
Additionally, the high aspect ratio and corresponding greater
surface area will increase the extent to which there is direct
contact between a chilled vane and a substantial portion of a
surface of the object to be cooled or chilled. One of ordinary
skill in the art will recognize that these disadvantages of
directional vanes do not solve the problem of product/drum sticking
exhibited by conventional apparatuses and methods. Nevertheless,
the disclosed apparatus may include some amount of directional
vanes in addition to the prominences.
[0040] As best illustrated in FIG. 1, the objects 11 to be cooled
or chilled are introduced into the inlet of the drum 12 and the
drum 12 is rotated.
[0041] Solid CO.sub.2 may be injected towards the inner surface 9
of the drum 12 from one or more first liquid CO.sub.2 nozzle 34',
34'' to produce a blanket of solid CO.sub.2 snow 21 on the inner
surface 9 between the prominences 38. The liquid CO.sub.2 is
introduced to the nozzle 34', 34'' via a header 13. In FIG. 1, the
first liquid CO.sub.2 nozzle 34' may be oriented to inject a stream
of solid CO.sub.2 at a first angular position of the drum 12,
generally between 50-130.degree. or the first liquid CO.sub.2
nozzle 34'' may be oriented to inject a stream of solid CO.sub.2 at
a converse first angular position of the drum 12 between
230-310.degree. with respect to vertical. Alternatively, each of
the first liquid CO.sub.2 nozzles 34', 34'' may be utilized, one of
which injects a stream of solid CO.sub.2 to a first angular
position between 50-130.degree. with respect to vertical and the
other of which injects a stream of solid CO.sub.2 to a converse
angular position between 230-310.degree. with respect to
vertical.
[0042] As the drum 12 rotates (assuming for the sake of argument,
in the clockwise direction), the gravity causes the objects 11 to
tumble downwardly from the prominences 37 and solid CO.sub.2 21 in
the recesses formed between the prominences 37 from the "left" side
of the drum (for example, just short of 270.degree.) towards the
bottom of the drum 12 (for example, at around 180.degree.) as that
side is rotated upwardly towards a top (for example, at around
0.degree.) of the drum 12. The drum 12 may be rotated in either
clockwise or counter-clockwise direction and one of ordinary skill
in the art will recognize that the angular positions described
herein may be adjusted to account for any change in rotational
direction. After the object 11 has tumbled away from that side of
the drum 11, solid CO.sub.2 21 is freshly deposited in the recesses
of a portion (for example, at around 270.degree.) of the drum 12
that is being rotated upwardly from a bottom of the drum 12 to a
top of the drum 12. Alternatively (or in addition to the deposition
of snow at around 270.degree.), the solid CO.sub.2 21 is freshly
deposited in the recesses of a portion (for example, at around
90.degree.) of the drum 12 that is being rotated downwardly from a
top of the drum to a bottom of the drum 12. In this manner, solid
CO.sub.2 that is diminished through sublimation or which is jarred
loose by bumping of the objects or which falls out of recesses by
the force of gravity may be replenished or partially replenished in
the recesses that are empty or partially empty. As a result, a
substantial area of the inner surface 9 of the drum 12 is separated
from the objects 11 by a layer of solid CO.sub.2 21.
[0043] A stream 38 of solid CO.sub.2 may also be injected by a
second liquid CO.sub.2 nozzle 36 to produce a blanket of solid
CO.sub.2 (not shown) on top of the object 11. The second liquid
CO.sub.2 nozzle 36 may also be used in conjunction with one or both
of the first liquid CO.sub.2 nozzles 34', 34''. This allows each
opposing layer of the object 11 to be cooled or frozen by contact
with solid CO.sub.2 21. In other words, the object 11 is sandwiched
between the solid CO.sub.2 21 in the recesses and the layer of
solid CO.sub.2 (not shown) on top of the object 11. The combination
of the two nozzle orientations and the prominences 37 allow both
sides of the object to contact the solid CO.sub.2, resulting in
more efficient cooling.
[0044] One of ordinary skill in the art will recognize that the
schematic illustration of FIG. 1 depicts a cross-section of the
invention at an axial position of the drum 12. Typically, there are
multiple first liquid CO.sub.2 nozzles 34' or 34'' each one of
which is oriented to inject a first stream of solid CO.sub.2 35' or
35'' at more or less a same first angular position. Thus, there are
typically multiple first streams 35' or 35'' of solid CO.sub.2 that
are parallel to, and spaced from one another in the axial direction
of the drum 12. Similarly, there are typically multiple second
liquid CO.sub.2 nozzles 36 each one of which is oriented to inject
a second stream 38 of solid CO.sub.2 at more or less a same second
angular position. Thus, there are typically multiple second streams
38 of solid CO.sub.2 that are parallel to, and spaced from one
another in the axial direction of the drum 12.
[0045] The objects 11 can traverse the drum 12 from an inlet to an
outlet of the drum 12 by force of gravity caused by a declination
of the drum 12 from the inlet to an outlet. The objects 11 can also
traverse the drum 12 through the use of direction vanes (not shown
in FIG. 1 that urges the objects 11 from the inlet to the outlet as
the drum 12 is rotated. The objects 11 are then removed from the
outlet of the drum 12.
[0046] As best shown in FIG. 2, the object 11 is introduced into
the inlet 22 of the drum 12 by a conveyor 10. One of ordinary skill
in the art will recognize that alternate methods of introduction
may also be used without departing from the teachings herein.
[0047] In the embodiment depicted in FIG. 2, the drum 12 is rotated
by drive motor 15 and drive wheels 16. One of ordinary skill in the
art will recognize that alternate mechanisms may be utilized to
rotate drum 12 without departing from the teachings herein. During
rotation of the drum 12, directional vanes 14 move the object 11
from the inlet 22 to the outlet 23.
[0048] In the embodiment depicted in FIG. 2, the chilled or frozen
object 11 exits the outlet 23 of the drum 12 via buckets 17 (in a
way well known to those skilled in the art of material handling)
and discharge slide 18. One of ordinary skill in the art will
recognize that alternate outlet mechanisms may be utilized without
departing from the teachings herein.
[0049] In the embodiment depicted in FIG. 2, liquid CO.sub.2 20 is
introduced via liquid CO.sub.2 injection header assembly 13 and
nozzles 22a and 22b. The liquid CO.sub.2 20 is expanded to solid
CO.sub.2 21 at nozzles 22a and 22b. Exhaust ducts 19 prevent the
CO.sub.2 gas from the escaping from drum 12 into the
atmosphere.
[0050] As best illustrated in FIG. 3, the object 11 (not shown in
FIG. 3) is introduced into the inlet 22 of the rotating drum 12 and
removed from the outlet 23. Cutaway portion 24 of rotating drum 12
provides further detail in FIGS. 4-6 of the interior surface 25 of
the rotating drum. FIGS. 4-6 are not drawn to scale.
[0051] As best shown in FIG. 4, one embodiment of the interior
surface 25 of rotating drum 12 includes prominences 37 having a
cylindrical configuration. The cylindrical prominences 37 extend
approximately 0.5 inches from the interior surface 25 as shown by
line z.sub.1 to z.sub.2 (height). Without limiting the scope of the
invention, the diameter of the cylindrical prominence 37 can be
approximately 1 inch as shown by line x.sub.1 to x.sub.2 and the
distance between cylindrical prominences 37 can be approximately 1
inch as shown by line x.sub.3 to x.sub.4.
[0052] As best illustrated in FIG. 5, the prominences 26 are
hemispherical. The hemispherical prominences 37 extend
approximately 0.5 inches from the interior surface 25 to its apex
as shown by line z.sub.1 to z.sub.2 (height). The diameter of the
hemispherical prominence 26 at its base is approximately 1 inch as
shown by line x.sub.1 to x.sub.2. The distance between
hemispherical prominences is approximately 1 inch as shown by line
x.sub.3 to x.sub.4.
[0053] As best shown in FIG. 6, the prominences 37 have a ridge
configuration. The ridged prominences 37 extend approximately 0.5
inches from the interior surface 25 to its apex as shown by line
z.sub.1 to z.sub.2 (height). The distance between ridged
prominences is approximately 2 inches as shown by line x.sub.3 to
x.sub.4. The ridged prominences 26 are approximately 0.5 inches
wide as shown by line x.sub.1 to x.sub.2. The length of the ridged
prominences 37 can vary from as much as one full revolution of the
inner surface of the drum 12 to any fraction of one full
revolution. The ridged prominences 37 may extend around the inner
surface at a same axial distance along an axis of the drum 12.
Alternatively, they may be formed as a single helix or as parallel
helices. One of ordinary skill in the art will recognize that,
depending upon the orientation of the ridged prominences 37, the
length (y.sub.1-y.sub.2) may equal or exceed the circumference of
the rotating drum 12.
[0054] One of ordinary skill in the art will recognize that other
shapes and/or greater or smaller diameters or widths
(x.sub.1-x.sub.2) or lengths (y.sub.1-y.sub.2) or heights
(z.sub.1-z.sub.2) of the prominences 37 or distances
(x.sub.3-x.sub.4) between the prominences 37 may be used without
departing from the scope of this invention. As discussed above, the
diameter and/or height of the prominences 37 is typically driven by
the ease with which they may be manufactured or by the shape and
size of the object 11 to be cooled or frozen. Furthermore, one of
ordinary skill in the art will recognize that uniformity amongst
the prominences is not required to practice the teachings of the
disclosed method and apparatus and that variation of shape, width,
length, height, and distance may occur within one drum 12.
[0055] It will be understood that many additional changes in the
details, materials, steps, and arrangement of parts, which have
been herein described and illustrated in order to explain the
nature of the invention, may be made by those skilled in the art
within the principle and scope of the invention as expressed in the
appended claims. Thus, the present invention is not intended to be
limited to the specific embodiments in the examples given above
and/or the attached drawings.
* * * * *