U.S. patent application number 12/718635 was filed with the patent office on 2010-12-23 for food container having improved ventilation.
This patent application is currently assigned to Anchor Packaging, Inc.. Invention is credited to Timothy Lee Cimmerer, Satya Garg, Michael Pohlman, Brent Riales, Michael Thaler.
Application Number | 20100320210 12/718635 |
Document ID | / |
Family ID | 43353399 |
Filed Date | 2010-12-23 |
United States Patent
Application |
20100320210 |
Kind Code |
A1 |
Cimmerer; Timothy Lee ; et
al. |
December 23, 2010 |
FOOD CONTAINER HAVING IMPROVED VENTILATION
Abstract
A plastic food container for crisp or crunchy foods includes a
lid adapted for sealing arrangement with a base. Exhaust vents are
selectively disposed on the top surface of the container, such that
when the container is closed, rising vapors in the container easily
flow out of the container. The convection movement of rising hot
vapors causes the induction of ambient air into the container
through a first air intake port and a counterpart air intake port
disposed between the two engaged rims. The first intake port and
its counterpart allow inducted air to enter directly and
horizontally into the container. One or more channels are formed in
the floor of the base and are aligned with a line defined by the
first intake port and its counterpart to allow for the cross flow
of drier inducted air underneath the container's food contents.
Inventors: |
Cimmerer; Timothy Lee;
(Paragould, AR) ; Garg; Satya; (St. Louis, MO)
; Pohlman; Michael; (Valley Park, MO) ; Riales;
Brent; (Paragould, AR) ; Thaler; Michael;
(Roswell, GA) |
Correspondence
Address: |
GALLOP, JOHNSON & NEUMAN, L.C.
101 S. HANLEY, SUITE 1600
ST. LOUIS
MO
63105
US
|
Assignee: |
Anchor Packaging, Inc.
St. Louis
MO
|
Family ID: |
43353399 |
Appl. No.: |
12/718635 |
Filed: |
March 5, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61218770 |
Jun 19, 2009 |
|
|
|
Current U.S.
Class: |
220/367.1 ;
220/810 |
Current CPC
Class: |
B65D 75/22 20130101;
B65D 51/1616 20130101 |
Class at
Publication: |
220/367.1 ;
220/810 |
International
Class: |
B65D 51/16 20060101
B65D051/16; B65D 43/16 20060101 B65D043/16 |
Claims
1. A plastic food container comprising: a lid and a base; the lid
and base each having a peripheral rim; the lid rim adapted for
closing engagement with the base rim; the lid rim and base rim when
in closed engagement forming an interior of the container, a first
intake port disposed between the two rims and a first counterpart
intake port disposed between the two rims; the first intake port
and the first counterpart intake port being further disposed
between the two engaged rims such as to permit air to enter
directly and generally horizontally into the container; the first
intake port and the first counterpart intake port defining a line
in the interior of the container that extends from the first intake
port to the first counterpart intake port; the base comprising a
floor, the floor having at least one channel formed therein that is
aligned with the line defined by the first intake port and the
first counterpart intake port; the lid including a top surface and
one or more outermost side surfaces, the one or more outermost side
surfaces having no vents disposed on them; and the top surface of
the lid having a plurality of exhaust vents disposed on it.
2. The container of claim 1 wherein the plurality of exhaust vents
disposed on the top surface of the container lid numbers between
eight and fourteen vents.
3. The container of claim 1 wherein the lid includes a contour and
the plurality of exhaust vents on the top surface of the lid are
disposed on the lid top surface so that they follow the contour of
the lid shape.
4. The container of claim 1 wherein the exhaust vents disposed on
the top surface of the lid are formed so that they direct rising
gases and vapors outward in relation to the outermost side surfaces
of the lid.
5. The food container of claim 1 wherein the lid rim and base rim
when in closed engagement form a second intake port disposed
between the two rims and a second counterpart intake port disposed
between the two rims; and the second intake port and the second
counterpart intake port are disposed between the two engaged rims
such as to permit air to enter directly and generally horizontally
into the container.
6. The container of claim 5 wherein the second intake port and the
second counterpart intake port define a second line in the interior
of the container that extends from the second intake port to the
second counterpart intake port and the floor has a second channel
formed therein that is aligned with the second line.
7. The container of claim 1 wherein the peripheral rim of the lid
comprises at least two sealing projections, the peripheral rim of
the base has a channel and when the lid and base are in the closed
arrangement the at least two sealing projections of the lid rim are
engaged by the channel in the peripheral rim of the base.
8. The container of claim 1 wherein the lid is hinged to the base.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/218,770, filed on Jun. 19, 2009. The content of
that application is incorporated by reference herein in its
entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
SEQUENCE LISTING, TABLE OR COMPUTER PROGRAM ON COMPACT DISC
[0003] Not applicable.
FIELD OF INVENTION
[0004] This invention relates generally to ventilated plastic food
containers. The invention is more specifically related to
disposable plastic food containers designed to hold heated or
freshly-cooked crisp, crunchy or texture-sensitive foods that
require significant amounts of humidity removal.
BACKGROUND OF THE INVENTION
[0005] It is known to use disposable plastic containers in the food
preparation and restaurant industry to package prepared or take-out
foods. The typical food container of the prior art consists of a
clear or solid color base and a clear lid. The clear lid of the
prior art plastic food container allows visible inspection of the
container contents. The lid and base of the prior art plastic food
container may be separate articles or may be hingedly attached to
each other.
[0006] The lid and base of the prior art plastic container have
complementary interlocking rim structures that seal the container.
This interlocking rim arrangement is beneficial in preventing
spillage of food contents from the container. In addition, this
interlocking rim arrangement promotes heat build-up inside the
container during microwaving and retains the temperature of hot
foods placed in the container. When warm foods are placed in a
closed container, steam and condensation can develop inside the
container. This is particularly so when the container with warm
food is placed into a storage area at room temperature or less.
Steam and condensation may also form inside a container holding
food when the container is stored in an environment where external
heat is applied to it (for example through microwaving, heat
plates, heat lamps, warming tunnels, etc.). The build up of
condensation and steam inside the container can result in the
over-moistening of the contained food. This build up is
particularly unwanted in the case of any food of sensitive texture,
especially crisp or crunchy foods. In addition, undesirable food
moistening is exacerbated when condensation drips down onto the
food contents. In extreme cases, the condensate may pool at the
bottom of the container leaving desirably crisp foods (e.g.,
vegetables) or crunchy foods (e.g., fried chicken or fried seafood)
unpalatably soggy.
[0007] In the case of supermarket fried chicken (or seafood) for
example, the supermarket prepares the fried chicken in its deli
department, resulting in a cooked food product having a temperature
of about 190 degrees Fahrenheit. After cooking, the hot fried
chicken is placed into the container. The container may be sold
immediately. If not, the container containing the fried chicken is
typically placed in a heated display area and made available for
sale as a "hot" food item for up to 4 hours. In the prior art
container, the heat from the hot chicken builds up in the container
and, in turn, causes moisture build-up in the container. As a
consequence to this moisture build-up, the fried chicken's crisp
battered coating becomes soggy.
[0008] The solution to preventing over-moistening of cooked food,
however, is not simply a case of providing unregulated venting. In
the first respect, unregulated venting allows the food to dry out
and over-harden. More importantly, in addition to palatability
concerns, containers for cooked foods must address safety issues.
If the container is vented too much, the temperature of the fried
chicken can drop below the minimum temperature required by health
departments or good food serving practice. These same concerns hold
true for other establishments like restaurants and with respect to
other texture sensitive foods like unbreaded cooked crab that can
degrade if heat and moisture are not properly removed from the
container.
[0009] In order to maintain the crispness of food contents within a
closed container, it is known to provide the prior art food
container with exhaust ventilation means. In this regard, the lid
of the prior art plastic food container typically contains one or
two surface vents in the form of cruciate slits. The cruciate slits
form near-circular tabs that can be deformed upward to permit
egress of steam formed inside the container. The one or two slits
are located on the surface of the container lid, not in relation to
other venting structures of the container, but instead in a manner
that detracts least from the aesthetic appeal of the container.
Though these slits assist in the exhaust venting of steam gases
from the container, moisture build-up inside the container still
occurs.
[0010] In the case of microwavable storage containers (as opposed
to deli case containers) manufacturers have chosen to deal with
removal of moisture damaging steam by constructing container rims
whereby the lid rim can assume two different positions on the base
rim. One position keeps the container sealed. The other position
allows exhaust venting. In the case of these latter containers, the
sealed lid assumes a second fixed exhaust venting position on the
base either through manual repositioning or by the lifting action
of rising pressure inside the container. Once the lid is in the
fixed exhaust venting position, steam can escape the container by
flowing along and between the contour of the rim structures and out
through the container. The contour of these rim structures can
require egressing steam to undergo flow restricting direction
changes (including direction reversals). The drawback to these
exhaust venting solutions is that they still result in the creation
of interior vapors and condensation in the container, particularly
in the case of the self-activating lid Also, because air must flow
around the contour of rims, these containers promote only the
egress of air out of the container and do not allow drying air into
the container.
[0011] U.S. Pat. No. 6,257,401 discloses a thermoplastic container
for food with a cover that is removably attached to the base to
define a food storage chamber. A downwardly extending rib formed in
the cover rim is intermittently provided with a plurality of
notches that are aligned with respective notches formed in an
upwardly extending elongated rib of the base. With the cover in
place atop the base, the conjunction of the base notches and the
cover notches define apertures. However, as is best shown in FIG.
11 of that patent, the notches of the lid rim and base rim are
offset, such that air flow into the container is directed upward
toward the upper apertures of the lid. Another set of apertures for
additional ventilation are provided in the side walls of the
cover.
[0012] Because of the venting drawbacks of the prior art container
with respect to desirably crisp or crunchy foods, container
manufacturers have designed containers having textured surface
grids on the container floor that keep the food contents raised
above pooled food juices or condensate. These grids can create
pooling areas that collect the condensate and juices. The container
of U.S. Pat. No. 6,257,401 includes a plurality of small wells in
the container bottom, the function of which is to purposefully
retain food juices via capillary action or surface tension. These
solutions, however, do not completely remedy the creation of
food-damaging steam and fluids inside the container. In fact, they
can make it worse. In particular, the condensate and juices may
drip into and pool in the wells of the container's floor grid and
be retained. This pooled liquid absorbs heat and creates rising
steam that infuses the lower portion of the container's food
contents with texture damaging moisture.
[0013] There is thus a need in the art for a plastic food container
that reduces steam creation and enhances container venting to
prevent over-moistening of desirably crisp or crunchy foods.
SUMMARY OF THE INVENTION
[0014] The present invention satisfies the need in the art and
provides an aesthetically appealing food container that is easy to
use, while providing for improved moisture removal. In this respect
the present invention container achieves balanced vapor removal by
incorporating structures that enhance the exhaust venting of the
container with structures that allow for efficient air intake. The
container uses convection and guided flow of inducted air to
prevent the over-moistening of food product.
[0015] The present invention comprises a plastic food container
including a lid and a base. The lid and base each have a peripheral
rim. The lid rim is adapted for sealing engagement with the base
rim. When the container is sealed with hot food contents, the heat
load created by the food causes the moisture laden air to rise and
exit through selectively positioned and numbered exhaust vents in
the top surface of the container lid. In this regard, the top
surface exhaust vents are numbered and positioned in relation to
the expected temperature and humidity of the container's contents.
The convection movement of warm moist air upwardly in the container
and through the top surface exhaust vents causes the induction of
air through the intra-rim intake ports hereinafter described.
[0016] It is a further feature of the present invention container
that the lid rim and base rim when in closed engagement form at
least one first intake port disposed between the two rims. To
achieve optimum balanced venting and eliminate humidity dead zones
in the container, each first intake port has a counterpart intake
port disposed between the two rims. Additionally, the first intake
port and its counterpart intake port are oriented such as to permit
air to enter, directly and generally horizontally, into the
container through them and not encounter obstructing rim structures
or have to change directions or angles while traveling through the
rims.
[0017] The first intake port and its counterpart intake port define
a line inside the container. The container's floor can have at
least one channel formed in it, which is aligned with the line
defined by the first intake port and a counterpart intake port. By
aligning the floor channels with at least one intake port, a cross
flow of inducted ambient air is allowed whereby the container
promotes the flow of relatively drier air under the container's
food contents. This flow of air not only helps evaporate collected
condensate and food juices, it removes the vapor away from the
underside of the food content, preventing its damaging absorption.
The container floor may comprise channels aligned with two or more
sets of intake ports.
[0018] In more specific summary, the present invention plastic food
container comprises a lid adapted for sealing arrangement with a
base. The lid has a peripheral rim structure that complementarily
engages the peripheral rim structure of the base. The base has a
floor and a sidewall extending between the floor and the rim. In
contrast to prior art containers utilizing through-the-rim exhaust
or intake venting, it is a feature of the present invention that
when the lid is fully closed to the base, the mating rim structures
create at least two intake ports that allow generally horizontal
and direct (unrestricted) flow of air into the container through
the closed rims. Preferably, each intake port is located on the rim
in opposing relationship to another intake port. Hence, each intake
port is located such that it is across from another intake port on
the other side of the container. The positioning of the intake
ports allows for the cross-flow of air through the container.
[0019] In the preferred embodiment, the rim structure of the lid
has a channel shaped to receive spaced apart projections on the
base rim structure. When the lid is closed to the base, the channel
of the lid rim structure receives the projections on the base rim
structure. The height of the projections emanating from the base
rim structure prevents the lid flange from sealing completely
against the base flange. As a result, when the lid is fully engaged
to the base, the spaces between the base rim projections create rim
air intake ports.
[0020] The present invention container further comprises elevated
(preferably embossed) projecting ribs from the base floor. These
ribs create one or more channels on the container floor that
compared to the prior art are specifically aligned with a line
defined by at least two intake ports located within the engaging
container rims. These ribs and channels provide for several
beneficial effects. First, as in the case with the grid or textured
surface of the prior art container, the ribs keep the food contents
elevated from the base floor and away from collecting liquids.
However, in combination with the intake ports, the aligned channels
act like baffles and allow for the free passage of gases and vapors
underneath the food contents. Thus, should pooled liquids in the
container start steaming, the channels of the present invention
container allow for the evacuation of steam out through the top
surface exhaust vents in the lid instead of into the food. In
addition, by virtue of their alignment with the intake ports, the
channels of the present invention container allow for the
end-to-end cross flow of moisture-removing air underneath the
container's food contents in the event a pressure differential
exists between the ends of the channels. This arrangement not only
enhances the removal of pooled moisture, but also aids in drying of
the bottom of the food contents. Thus, the convective movement of
warm air inside the container causes induction of air through the
rim intake ports. That air, being relatively cooler than the
existing vaporous air inside the container, drops to the floor of
the container. This drop is effected, in part, by the generally
horizontal (not upwardly angled) orientation of the rim intake
ports. Once the cool, dry air reaches the container floor, it flows
as guided by the channels. Thus, the intake ports along with the
aligned, one or more channels allow the direct, unimpeded flow of
relatively dry air to enter into the container from the intake
ports and pass under the food contents. While passing under the
food contents, heat is transferred from the food contents to the
incoming air. That heated air rises, scavenging moisture from the
existing air in the container as it rises.
[0021] To further enhance the convection flow in the container, the
preferred embodiment container includes a plurality of exhaust
vents disposed about the top surface of the container lid and not
along any of the lid's outermost side surfaces. This arrangement of
top-surface-only vents removes the dead-air effect caused by having
apertures on the side of the lid in close proximity to the rim
intake ports. By removing this dead-air effect, convection in the
container is enhanced. In addition, by removing the vents from the
extreme side of the lid by the intake ports, rising air in the
container does not intercept the inducted air from the intake ports
and push it out of the container.
[0022] While the invention is susceptible to various modifications
and alternative forms, a specific embodiment thereof has been shown
by way of example in the drawings and will herein be described in
detail. It should be understood, however, that it is not intended
to limit the invention to the particular forms disclosed. Quite to
the contrary, the intention is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope
of the invention as defined by the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a perspective view of a preferred embodiment of
the present invention container in the open arrangement.
[0024] FIG. 2 is a perspective view of a preferred embodiment of
the present invention container in the closed arrangement.
[0025] FIG. 3 is a plan view of the present invention container in
the open arrangement.
[0026] FIG. 4 is a cross-section view taken along line A-A of FIG.
3.
[0027] FIG. 5 is a side elevation view of the preferred embodiment
present invention container in the closed arrangement.
[0028] FIG. 6 is a perspective view of the inside of the base of
the preferred embodiment present invention container.
[0029] FIG. 7 is a perspective view of the inside of the lid of the
preferred embodiment present invention container.
[0030] FIG. 8 is a side elevation view of the lid of the preferred
embodiment present invention container.
[0031] FIG. 9 is a side elevation view of the base of the preferred
embodiment present invention container.
[0032] FIG. 10 is an enlarged view of detail area Z of FIG. 4.
[0033] FIG. 11 is an enlarged view of detail area Y of FIG. 4.
DETAILED DESCRIPTION
[0034] A preferred embodiment container 10 of the present invention
in the open and closed arrangement is shown in FIGS. 1 and 2. In
practical use, the outer surface of floor 31 of base 25 will
normally rest upon a surface (such as a table top) considered
horizontal in reference to the user. Thus, the directional terms
"vertical" and "horizontal" and the like are used to describe the
container 10 and its components with respect to the orientation
illustrated in FIG. 2 and are employed merely for the purposes of
clarity and illustration. For example, in the orientation shown in
FIG. 2, lid 11 of closed container 10 is spaced "vertically" from
the base 25. The directional terms "inner," "outer," and the like
are used herein with respect to the described container to refer to
directions along the directional component toward and away from the
geometric center of the container.
[0035] Container 10 is preferably thermoformed. As shown by the
figures, container 10 is composed of lid 11 and base 25. Lid 11
includes top surface 12, descending surface (sidewall) 19 and
multi-segment rim 14. Lid 11 and base 25 are manufactured from a
conventional plastic material. Lid 11 is preferably clear. Top
surface 12 may include levels or features of varying height, but is
preferably flat. It may also be contoured and have ribs 16 in
accordance with the prior art to enhance such factors as container
volume, strength, nesting of multiple lids, stackability of closed
containers and see-through visibility. In the preferred embodiment,
lid top surface 12 includes top plateau 15. Sidewall 19 extends
from top surface 12 to horizontal segment 17 and may include ribs
13 for strength. Horizontal segment 17 extends from sidewall 19 to
vertical inner wall 18. Sidewall 19 preferably includes ribs 7 for
strength and, in the depicted preferred embodiment, represents an
outermost side surface of the lid.
[0036] The structure of preferred embodiment lid rim 14 will now be
discussed in further detail. As best shown in FIG. 10, lid rim 14
includes peripherally projecting segment 20, which extends between
inner wall 18 and outer wall 21, creating channel 23. The
cross-section profile of segment 20 is generally horizontal. The
profile, however, can be shaped to include structure such as
ribbing, curves or bends to modulate rim rigidity or flexibility so
as to enhance the closing, sealing and opening functions of the rim
as needed. The drawings depict a preferred embodiment cross-section
profile of this peripherally projecting segment. As viewed in FIG.
10 outer wall 21 extends downwardly between peripherally projecting
segment 20 and peripheral flange 22. Outer wall 21 is preferably
angled to frictionally engage projection 35 further described
below.
[0037] The structure of preferred embodiment rim structure 30 of
base 25 is best shown in FIG. 11. Base 25 includes a bottom-most
level or floor 31 adjoined to sidewall 32. Sidewall 32 extends
between base floor 31 and multi-segment rim 30. Sidewall 32
preferably includes ribs 41 for strength. The structure of base rim
30 is adapted to complementarily engage the structure of lid rim 14
when lid 11 and base 25 are placed in sealing arrangement. In this
respect, the lower portion of base rim 30 includes sidewall-to-rim
transition segment 33. Transition segment 33 flares outwardly from
the top of sidewall 32 and curves upwardly into base shelf 34. Base
shelf 34 extends outwardly from base 25 and curves upwardly to form
sealing projection 35. Preferred embodiment container 10 has at
least two sealing projections 35. As viewed in FIG. 11, sealing
projection 35 comprises outer vertical segment 36 and inner
ascending segment 37. Top sealing segment 38 spans between segments
36, 37. Peripheral flange 42 extends outwardly from segment 36.
[0038] As shown in FIG. 9, projections 35 are located at spaced
apart intervals on shelf 34 so as to create base rim gaps 39
between two adjacent projections. Each base rim gap 39 is
preferably located so as to geometrically oppose a counterpart base
rim gap 39 located on the container. For example, in the disclosed
embodiment square container depicted in FIG. 1, base rim gaps 39
are disposed in opposing relationship on each pair of parallel
container sides. Lid rim structure 14 preferably contains similar
projections 26 located on horizontal segment 17. Projections 26 are
complementarily located on rim structure 14 such that they align
with and frictionally contact projections 35 when lid 11 is closed
to base 25. Projections 26 serve to buttress projections 35 and
keep lid 11 from twisting about base 25. Lid rim gaps 27 are
disposed between projections 26 on lid rim 14. In addition, by
frictionally engaging projections 35, projections 26 make the
engagement between lid 11 and base 25 stronger. As shown in the
drawings, the height of projections 35 emanating from the base rim
structure prevents lid flange 22 from sealing completely against
base flange 42. As a result, when the lid is fully engaged to the
base, projections 35 of base rim 30 are engaged by channel 23 and
projections 26 of lid rim 14. However, the height of engaged
projections 35 is such that flange 22 and flange 42 do not meet
when the lid is engaged by the base. In this regard, when the
container is closed, one or more lid rim gaps 27 between
projections 26 of the lid align both vertically and horizontally
with a base rim gap 39 of the base rim. Hence, base rim gaps 39
between the base rim projections are now roofed by rim 14 and
create at least two rim intake ports 40 that allow air to directly
enter the container generally horizontally.
[0039] In carrying out the invention it is not important which rim,
lid or base, is provided with the projections 35 or the engaging
channel 23. Accordingly, in another embodiment, base rim 30 could
be provided with channel 23 and lid rim 14 could be provided with
projections 35. In fact, other rim engaging methods could be used
as long as the sealing rim structures of the lid and base create
intake ports 40 when the rims are in sealing arrangement.
[0040] When the lid rim and base rim are in sealing arrangement,
the container comprises at least one set of counterpart intake
ports 40 (a first intake port and a first counterpart intake port).
More specifically, in the present invention container, the lid rim
and base rim when in closed engagement form at least one first
intake port disposed between the two rims. In addition, it is a
feature of the invention that each first intake port has at least
one first counterpart intake port disposed between the two rims. In
contrast to prior art containers, the intake ports of the present
invention allow air to flow directly through the rims of the
container and not travel a serpentine course through rim structure.
In addition, in comparison to prior art containers, the intake
ports of the present invention allow air to flow directly into the
container in a generally horizontal manner without having to travel
an angled path. Hence, in the present invention intake ports 40 are
not angled toward the container top.
[0041] The at least one first intake port and its one or more first
counterpart intake ports are disposed between the two rims such as
to permit air to enter the container through an intake port, cross
at least a portion of the interior of the container under the food
contents and then, as it warms, rise and exit the container through
the exhaust vents in the top surface of the lid. For balanced
moisture removal, each first intake port 40 is located in the
engaged rims 14, 30 and has at least one first counterpart intake
port 40 similarly located in the engaged rims 14, 30. In the shown
preferred embodiment container, each first intake port 40 is
located on the closed container such that it geometrically opposes
(is perpendicularly across from) one counterpart intake port 40 on
the other side of the container. This arrangement enables the
cross-flow of air underneath food contents throughout the entire
container in the case of a pressure differential between the ends
of the one or more channels. The invention thus allows drier air to
flow into the container through an intake port 40, under the
container contents and out through the exhaust vents 28 in the top
surface of the lid. Though the depicted embodiment container shows
an intake port 40 to have only one counterpart intake port 40, an
intake port 40 may have more than one counterpart intake port
40.
[0042] Floor 31 includes two or more ribs 50 and may have
alternating levels or elevations for strength and fluid control. To
further enhance food crispness, floor 31 of base 25 comprises ribs
50 in floor recess 51. Floor recess 51 is a preferred embodiment
feature. Ribs 50 project upward from floor recess 51. Spaced apart
elongated ribs 50 are aligned with the line defined by at least one
set of counterpart intake ports 40 and form at least one channel
55. The one or more channels 55 act as flow paths for the
relatively drier air inducted into the container through intake
ports 40. In this regard, the formation of aligned channels 55 on
floor 31 differs from the prior art container with floor bottoms
provided with grids, wells or other structural features intended to
capture and retain liquid. These structural floor elements, though
useful in preventing sloshing of liquids or keeping food raised
above pooled liquids serve as barriers to air flow underneath the
container's food contents.
[0043] In the depicted preferred embodiment the one or more
channels 55 are lengthwise centered along one dimension of the
floor and extend substantially across the length of the floor.
Further, recess 51 is formed in floor 31 so as to guide incoming
air to the channels and allow incoming air to fan (branch) out to
the multiple of channels disposed in it. The at least one channel
55 is oriented such that it extends in the direction of one set of
counterpart intake ports 40 and thus the sides of the channel act
like interior baffles. In the disclosed embodiment, the container
depicts six channels 55 aligned with intake ports 40 disposed on
the ends of the container. By virtue of being oriented in this
fashion, channel 55 allows steam gases that may form from pooled
liquid to rise and be conveyed away from food contents by
convection, thus reducing the over-moistening of the bottom of
food. Additionally, by virtue of the intake ports 40, drier air may
flow into intake ports 40 and around and under the container
contents. Specifically, by virtue of the baffle effect of channel
55, drier air entering into the container through an intake port 40
may flow under food contents and exit out through top surface
exhaust vents 28. In an alternative embodiment, floor 31 could
comprise a plurality of channels 55, at least two of which are
aligned in two different directions so as to provide channels that
align with more than one set of counterpart intake ports 40.
Additionally, in the preferred embodiment, floor 31 includes
textured surface platforms 52. Platforms 52 are embossed (raised)
above the interior surface of floor 31 (and thus substantially
higher than the surface of recess 51). By virtue of this
arrangement, food contents are lifted off the surface of floor 31
and the drier air entering the container from the intake ports 40
can more easily flow under the food contents and into the one or
more channels 55.
[0044] The terms "opposing," "opposed" or "opposite" as used herein
to describe the location of the base rim gaps 39 or intake ports 40
means that the gaps or portals are oriented to allow the flow of
ventilation into the container through one port, through a certain
length or width of the interior of the container and then toward at
least one other intake port. Hence, in the depicted rectangular
container embodiment, a first intake port 40 is situated on one
side of the container and a counterpart intake port 40 is located
across the container on the opposing parallel side of the
container. In this case, the at least one other counterpart intake
port 40 would be preferably, but not necessarily, located
perpendicularly across from the first intake port 40. Similarly,
with a round container, the set of counterpart intake ports 40
would be preferably, but not necessarily, diametrically across from
each other. Variations in the locations of counterpart ports 40
(and gaps 39) and the alignment of the floor ribs 50 and channel 55
may be made such that air only flows through a portion of the
container and not its entire width or length. For example, in a
rectangular container the intake ports 40 could be located on
adjacent sides of the container to promote the diagonal flow of
cross ventilation. The cross flow of ventilation in such an
embodiment would be enhanced by having one or more diagonally
oriented floor channels 55 aligned with the intake ports.
Additionally, each intake port 40 preferably has at least one
counterpart intake port 40 to achieve cross flow ventilation. Thus,
an intake port 40 could have more than one counterpart intake port
40.
[0045] As shown in FIG. 2 to further enhance the convection flow in
the container, the lid of the preferred embodiment container
includes a plurality of exhaust vents 28 disposed about the top
surface 12 of the container lid. For optimum convection movement in
the container, it is critical that exhaust vents 28 be disposed and
arranged on the top surface 12 of the container and not on any of
the outermost side surfaces of the lid. Otherwise, the inductive
action on intake ports 40 is lessened or the inducted air may not
have an opportunity to drop to the container floor before being
pushed out by convection forces. At the same time, to enhance
convective movement inside the container it is preferable that the
plurality of exhaust vents 28 on the top surface 12 of the lid be
disposed away from the lid center so that they follow the contour
(as viewed from overhead) of the lid shape. In the depicted
embodiment shown in FIG. 2, an exemplary number and arrangement of
surface exhaust vents is shown on an approximately 9''.times.8''
rectangular container. Tests on this exemplary embodiment show that
the optimum convection movement in the container occurs with a
plurality of 14 exhaust vents disposed in the shown pattern about
the periphery of the top surface of the lid and located within the
range of 1'' to 11/4'' (measured from the front edge of the vent)
from the nearest outer edge of the top surface of the container.
For most food service applications (side dish sized containers to
entree sized containers) a plurality of at least 8 top surface
exhaust vents 28 works well, with the range of 8 to 14 vents
(cruciate slit type) showing optimum results. As shown in FIG. 2,
it is further preferable that exhaust vents 28 be disposed so that
they direct rising gases and vapors outward in relation to the
container's outermost exterior side surfaces. This arrangement of
exhaust vents on the lid top surface and the absence of vents on
the outermost side surfaces of the lid removes the dead-air effect
caused by having apertures on the side of the lid in close
proximity to (particularly above) the rim vents. By removing this
dead-air effect, convection in the container is enhanced.
[0046] A container constructed in accordance with the present
invention can be manufactured in a variety of shapes and sizes, and
is preferably formed of resins or plastic materials including, but
not limited to, polyethylene, polypropylene, polyvinyl chloride or
polyethylene terephthalate ("PET"). The container lid and base can
be transparent or translucent, and may be colored in either
instance. The size and number of intake and exhaust vents can be
varied to accommodate the food heating environment or the
requirements of the food placed in the container. The container can
be made by a variety of processes including thermoforming, vacuum
forming,, blow molding, extrusion molding or injection molding.
Further, the container can be of any shape, including round or
polygonal. The lid and base of the container may be separate
articles or may include the depicted hinge such that the lid and
base are connected to each other in a clamshell configuration.
[0047] Having described the invention in detail, those skilled in
the art will appreciate that modifications may be made of the
invention without departing from its spirit. Therefore, it is not
intended that the scope of the invention be limited to the specific
embodiment illustrated and described.
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