Note: Descriptions are shown in the official language in which they were submitted.
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SLOW COOKER WITH THERMOMETER FOR INDICATING A
TEMPERATURE CONDITION OF THE FOOD IN THE COOKING VESSEL
BACKGROUND OF THE INVENTION
Slow cooker appliances have been broadly used in households since at least the
1970's and are commonly used for a variety of purposes. Slow cookers are
convenient
ways to cook a wide variety of foods including, but not limited to, soups,
stews, dips,
chilis, roasts, and other large cuts of meat at a lower temperature for
extended periods of
time. One benefit of slow cookers is that a user may add all the ingredients
for a meal,
namely, the meat, starches, vegetables, and so forth, together into one
appliance and it will
"slow cook" during the day and be ready for consumption at dinner time. Many
slow
cookers only have a "cooking" setting and an "off' setting. Some slow cookers
may
include a "warm" setting however the "warm" setting often may only be
activated after a
pre-determined cooking cycle has been completed.
Often times, slow cookers are used at potluck dinners, family reunions,
smaller
restaurants/bars, parties or other applications for holding and serving food
items for an
extended period of time. In this situation, the slow cooker is often
transported from the
cooking location to the serving location. Further, these events often require
the food to be
made available for serving for prolonged periods of time. Once the desired
food product
has finished cooking in the slow cooker, it is desirable to keep the food
product at a
comfortable consuming temperature in the slow cooker, rather than at the
"cooking"
temperature. Unfortunately, as stated above, since most slow cookers only have
a
"cooking" setting and an "off' setting, keeping the food product at a
comfortable
consuming temperature is oftentimes problematic. Thus, to prevent the served
food
product in the slow cooker from (1) being too hot to eat, (2) burning or over
cooking, or
(3) drying out the contents due to boiling off of the liquid or moisture
associated with the
food product, most users often serve the food product with the slow cooker
turned off.
This situation presents other undesirable issues including not being able to
control the
serving temperature of the food product in the slow cooker.
Leaving a food product unheated for a prolonged period of time presents
obvious
risks. First, if food is left unheated too long, it may become too cold and
will not be at an
ideal consuming temperature. Second, if the temperature of the food product
gets too low,
CA 02805830 2013-02-11
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bacteria may reappear and/or start to grow. Thus, to prevent the served food
product from
getting too cold so as to be unappetizing, or worse, harmful to the consumer,
it is desirable
to monitor the temperature of the contents of the food in the slow cooker.
There is
therefore a need for a slow cooker which provides users with some indication
of the actual
temperature of the food product inside the cooking vessel so that a user can
selectively re-
heat the food product, if necessary, to keep the food product at an optimal
serving
temperature. There is also a need for a slow cooker that incorporates a heat
sensor and/or
thermometer combined with a visual/graphic indicator which will allow a user
to monitor
the temperature of the food product inside the cooking vessel after cooking
and while the
food product is being served.
SUMMARY OF THE INVENTION
The present invention teaches the construction and operation of several
embodiments of a slow cooker that incorporates a thermometer for providing a
visual
indicator of the food product temperature contained therein thereby allowing a
user to
monitor the temperature of the food contents inside the cooking vessel. The
present slow
cooker includes components associated with typical slow cookers including, but
not
limited to, a housing, a cooking vessel, a lid having a lid handle, a food
temperature
indicator display, an electronic control panel, a heating element controlled
by the
electronic controls, a power cord and a pair of handles extending from the
slow cooker
housing for transporting the slow cooker from one location to another. The
slow cooker
may also include a latch mechanism for securing the lid to the cooking vessel
and to the
housing.
In one embodiment, the present slow cooker may include an opening in the lid
which may include a one-way valve that acts as a vent. The vent may release
steam or
vapor when the pressure inside the cooking vessel gets above a pre-determined
limit.
Alternatively, the opening may also allow for insertion of a temperature probe
directly into
the food contents being heated inside the cooking vessel. The present slow
cooker may
additionally include a pair of arms coupled to the outer surface of the
housing, these arms
being configured to allow the power cord to wrap therearound for stowing the
power cord
when not in use or during transport.
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In one embodiment, the thermometer used with the present invention may be a
capillary thermometer positioned under the cooking vessel. The capillary
thermometer
measures the actual temperature of the outer wall of the cooking vessel and
uses an
established correlation to estimate and display the approximate temperature of
the food
items inside the cooking vessel. Since
the capillary thermometer measures the
temperature of the cooking vessel, and not specifically the temperature of the
food product
therewithin, a temperature difference does exist between the measured cooking
vessel
temperature and the actual temperature of the food product contained
therewithin. A
correlation can be established to account for this differential in temperature
between the
actual temperature of the food product within the cooking vessel and the
measured
temperature of the cooking vessel. For example, this temperature differential
can be
established by experimental testing or other means such that the temperature
displayed on
the food temperature indicator represents at least an approximate temperature
of the food
contents inside the cooking vessel as will be hereinafter further explained.
The capillary thermometer may be positioned in a housing assembly located
beneath the cooking vessel of the slow cooker. The housing assembly includes a
top cap
which may protrude through an opening in the bottom of the slow cooker housing
so that
the upper portion of the top cap is in direct contact with the bottom wall of
the cooking
vessel when the cooking vessel is positioned and seated in the housing. The
upper portion
of the top cap and the capillary thermometer disposed therein may be spring
loaded to
ensure that the upper portion of the top cap is always urged against the
bottom wall of the
cooking vessel. The capillary thermometer may be connected to a graphic offset
display
positioned in the control panel on the outside of the slow cooker housing. The
graphic
display is offset based upon the estimated correlation to account for the
differential
between the actual temperature of the food product inside the cooking vessel
and the
measured temperature of the exterior wall of the cooking vessel as sensed by
the capillary
thermometer. The food temperature indicator may indicate whether the food in
the
cooking vessel is hot, cool, or is in some range between hot and cool.
For example, one embodiment of the food temperature indicator display may have
a dial which points to color coded degradations on the display face that
signify whether the
estimated food temperature is "cool" which may be represented by a yellow
degradation,
"hot" which may be represented by a red degradation, or a degradation, for
example of a
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color between yellow and red, to represent a temperature between cool and hot.
The food
temperature indicator may be connected to the capillary thermometer via a tube
associated
with the capillary thermometer and housed within the housing assembly. The
tube and
capillary thermometer may be filled with a fluid that has a coefficient of
expansion which
results in the fluid expanding and contracting as the capillary thermometer is
heated and
cooled.
The expanding and contracting fluid within the capillary thermometer causes
the
fluid in the tube to fl ow back and forth inside the tube and, as it does so,
the fluid urges
against a spring biased dial indicator associated with the food temperature
indicator
display thereby causing the dial indicator to rotate to a color degradation
corresponding to
an approximate temperature of the food product within the cooking vessel.
Thus, the
approximate temperature of the food may be visually illustrated on the
exterior of the slow
cooker, i.e., cool, hot, or somewhere in between using the capillary
thermometer and the
food temperature indicator. One embodiment of the present invention includes a
capillary
thermometer and display requiring no power in order to measure and display the
temperature of the food within the cooking vessel. As a result, the
temperature of the food
within the cooking vessel may be constantly measured and displayed despite the
power
cord of the slow cooker being disconnected from a power source.
The present cooking vessel may also include a sidewal 1 that is thicker than
the
sidewall associated with typical cooking vessels of this type. This may be
beneficial to
prolong the heat retention of the food product within the cooking vessel.
Other aspects and advantages of the present invention will be apparent from
the
following detailed description of the several embodiments and the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings form a part of the specification and are to be read
in
conjunction therewith, in which like reference numerals are employed to
indicate like or
similar parts in the various views.
FIG. 1 is a perspective view of one embodiment of the present slow cooker
constructed in accordance with the teachings of the present invention;
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FIG. 2 is a cross-sectional view of the housing of the slow cooker of FIG. 1
taken
along line 2-2 of FIG. 1;
FIG. 3 is a front elevational view of one embodiment of a control panel
associated
with the present slow cooker constructed in accordance with the teachings of
the present
invention;
FIG. 4 is a cross-sectional view of one embodiment of a thermometer and a
thermometer housing assembly constructed in accordance with the teachings of
the present
invention;
FIG. 5 is a bottom view of the thermometer and thermometer housing assembly of
FIG. 4;
FIG. 6 is a cross-sectional view of the present slow cooker of FIG. 1 taken
along
the line 6-6 of Fig. 1; and
FIG. 7 is a partial top view of one embodiment of a vent in the lid of the
present
slow cooker constructed in accordance with the teachings of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
The following detailed description of the present invention references the
accompanying drawing figures that illustrate specific embodiments in which the
invention
can be practiced. The embodiments are intended to describe aspects of the
present
invention in sufficient detail to enable those skilled in the art to practice
the invention.
Other embodiments can be utilized and changes can be made without departing
from the
spirit and scope of the present invention. The present invention is defined by
the
appended claims and, therefore, the description is not to be taken in a
limiting sense and
shall not limit the scope of equivalents to which such claims are entitled.
Slow cooker appliances such as that disclosed herein include, but are not
limited
to, the slow cookers disclosed in US Patent Nos. 6,740,855; 6,587,739; and
7,312,425,
The slow cooker of the present invention includes a thermometer which detects
the
temperature of the cooking vessel and relates that temperature to the
temperature of the
food product being cooked within the cooking vessel.
Referring to FIG. 1, there is illustrated a slow cooker 10 including, but not
limited
to, a housing 12 having a thermometer 14 (see FIG. 2) operably disposed
therein, a
cooking vessel 16 seated within the housing 12, and a lid 18 configured to
removably seat
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on and cover cooking vessel 16. As best shown in FIG. 2, housing 12 includes a
sidewall
20, a bottom wall 22, and an open top 24 defined by a top annular rim 26.
Sidewall 20
includes an inner wall 28 and an outer wall 30 defining a sidewall thickness
therebetween.
Bottom wall 22 includes a bottom inner wall 32 and a bottom outer wall 34 also
defining a
bottom thickness therebetween. Inner wall 28 of sidewall 20 and/or inner wall
32 of
bottom wall 22 includes an opening or recess 40 defined therein for receiving
the
thermometer 14 therethrough or therewithin. Housing 12 further includes at
least one
heating element 38 positioned and located between inner walls 28 and 32 and
outer walls
30 and 34 as shown.
Inner walls 28 and 32 may be comprised of a wide variety of materials
including
aluminum, stainless steel, copper, or any other known commercial alloy or
other suitable
material. Metal inner walls 28 and 32 are beneficial in transferring heat from
housing 12
to the cooking vessel 16. Outer walls 30 and 34 may also be comprised of
aluminum,
stainless steel, copper, or any other known commercial alloy, glass, carbon
fiber,
composite, ceramic, or some temperature resistant plastics depending upon the
amount of
heat that is transferred to outer walls 30 and 34. The selection of the
material of outer
walls 30 and 34 may be made for both functional and aesthetic reasons. Other
similar and
functionally equivalent materials now known or hereafter developed may be used
for both
inner walls 28 and 32, and outer walls 30 and 34. Outer wall 30 of sidewall 20
may also
include opposing handles 42 coupled thereto as shown in FIGS. 1 and 2.
Referring back to FIG. 1, a control panel 44 may be coupled to outer wall 30
as
shown. FIG. 3 illustrates one embodiment of control panel 44 that includes a
plurality of
electronic controls including, but not limited to, one or more of the
following: an on/off
switch 46, a timer 48, a cooking mode indicator 50, a cooking mode switch 52,
and a food
temperature graphic display 54. Slow cooker 10 is generally a standard plug-in
type
electrical cooking device which includes a power cord 59 as best illustrated
in Fig. 6. It is
however also recognized and anticipated that slow cooker 10 could be
configured to be
alternatively powered by battery or some other power source. On/Off switch 46
turns
slow cooker 10 on and off. Timer 48 may display the current time, the
remaining cooking
time, the actual cooking time, and/or other timer or clock features now known
or hereafter
developed.
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Cooking mode indicator 50 displays which cooking mode or temperature range has
been selected by a user through cooking mode switch 52. Common examples are:
low,
medium, high, or warm. As shown in FIG. 3, one embodiment includes indicators
which
are designated as "HI," "LO," and "WM." Alternatively, cooking mode indicator
50 may
display an actual cooking temperature and/or time duration to be selected by
the user.
Cooking mode indicator 50 may also include an indication of cooking time
ranges
associated with each cooking temperature range. For example, in the embodiment
illustrated in Fig. 3, control panel 44 may include a cooking mode indicator
50 that
displays several operating times for each of the HI and LO settings such as
preset times of
4 hours and 6 hours for the HI setting, and 8 hours and 10 hours for the LO
setting. In one
embodiment, slow cooker 10 may operate at a high temperature for about four
(4) hours
and then switch to a warming mode. One embodiment may also include a warming
mode
that is either (1) activated after the completion of the selected cooking mode
and time
duration, or (2) a separate setting chosen by the user. Still further, mode
indicator 50 may
be an LED or other light positioned next to the written description of the
cooking mode,
time or temperature. It is recognized and anticipated that still other
settings may be used
and any configuration of preset times and cooking temperatures may be
incorporated into
control panel 44 and slow cooker 10 and all such variations are intended to be
within the
scope of the present invention.
As best shown in FIGS. 1 and 2, housing 12 may also include a plurality of
legs 56
extending away from bottom wall 22. Legs 56 may be integrally formed with
bottom wall
22 or they may be coupled thereto using any known coupling or fastener means.
One
embodiment of housing 12 may include hooks 60 that are configured to engage a
latch
mechanism associated with lid 18 as will be further described below.
As best illustrated in FIGS. 2 and 4, housing 12 of slow cooker 10 includes a
thermometer 14 having a temperature sensing device 61 positioned and located
within a
thermometer housing assembly 62 that is received into or extends through the
housing
recess or opening 40. As shown in FIG. 4, thermometer housing assembly 62
includes a
top cap 64, a bottom cap 66 configured to receive top cap 64, and a spring
member or
other biasing member 68 operably positioned between top cap 64 and bottom cap
66. Top
cap 64 further includes an annular sidewall 70, a top wall 72, and an open
bottom 74
defined by a bottom rim 76 of sidewall 70. Sidewall 70 includes an inner
surface 78 and
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an outer surface 80. Top wall 72 also includes a top inner surface 82 and a
top outer
surface 84 as shown. One embodiment of top cap 64 includes a plurality of legs
86 which
extend downwardly away from rim 76, the legs 86 extending through
corresponding
openings or slots 104 in the bottom cap 66 for holding the top cap in
operative position on
the bottom cap.
Bottom cap 66 includes an annular sidewall 88, a bottom wall 90, and an open
top
92 defined by top rim 94. Sidewall 88 includes an inner surface 96 and an
outer surface
98. Bottom wall 90 includes a bottom inner surface 100 and a bottom outer
surface 102.
Bottom outer surface 102 may include one or more slots 104 therein, the slots
104 being
complimentary to legs 86 of top cap 64. Legs 86 may pass through slots 104 and
thereby
function as a guide to properly orient the respective caps to each other and
to prevent top
cap 64 from rotating within bottom cap 66. Alternatively, top cap 64 may
include other
guiding mechanisms, such as pins, rods, grooves, projections or other similar
structures
(not shown) that engage bottom cap 66.
Although any temperature sensing device 61 (FIG. 2) can be used in the present
invention to measure the temperature of the cooking vessel 16, as illustrated
in FIGS. 4
and 5, a preferred embodiment of the temperature sensing device 61 includes a
capillary
thermometer having a capillary fluid reservoir 106 positioned against top
inner surface 82
of top cap 64 as shown. Capillary fluid reservoir 106 may be coupled to the
top wall 72 of
top cap 64 using one or more mounting flanges 108 as shown in FIG. 5. The top
wall 72
and the capillary fluid reservoir 106 are in thermal communication with each
other and
both are in thermal communication with the bottom surface of the cooking
vessel as will
be further explained. The capillary thermometer further includes a capillary
tube 110 that
is in fluid communication with both the capillary fluid reservoir 106 and the
food
temperature display 54 as will likewise be further explained.
Capillary fluid reservoir 106 and capillary tube 110 may contain any fluid now
known or hereafter developed which expands and contracts when it is heated and
cooled.
In one embodiment of the present invention, tube 110 and capillary reservoir
106 are filled
with kerosene which has a thermal coefficient of expansion of 0.00100/ F.
Other suitable
fluids having similar coefficients of expansion, such as ethyl alcohol or
gasoline, may also
be used. However, it shall be appreciated by a person of skill in the art that
there are
numerous configurations of the volume of fluid, diameter of tube, and
sensitivity of food
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CA 02805830 2013-02-11
temperature display 54 that may be used to accurately and successfully measure
the
temperature of cooking vessel 16. The expanding and contracting fluid within
the
capillary thermometer causes the fluid in the tube 110 to flow back and forth
inside the
tube and as it does so the fluid urges against a spring-biased dial indicator
55 associated
with food temperature display 54 so as to cause the dial indicator 55 to
rotate to a color
degradation or other scale parameter corresponding to at least an approximate
temperature
of the food product within the cooking vessel 16. This enables a user to at
least visually
determine what the approximate temperature of the food product is at all
times, namely,
hot, cool or somewhere in between. The accuracy of the correlation between the
measured
cooking vessel wall temperature and the actual temperature of the food
contents
therewithin will determine the accuracy of the estimated temperature of the
food contents
as discussed below. In another embodiment, the food temperature display 54 may
be
replaced with an electronic digital display having light emitting diodes to
represent a color
degradation or other scale parameter corresponding to at least an approximate
temperature
of the food product within the cooking vessel 16. A portable or replaceable
power source
such as batteries or other power means unrelated to the power source powering
the slow
cooker 10 such as power cord 59 can be utilized to power the electronic
digital display 54
when the slow cooker 10 is unplugged and is being utilized in its serving
mode.
Other temperature sensing devices 61 may also be used in place of a capillary
thermometer, including a digital thermometer operating on conventional battery
power or
a rechargeable battery that charges while slow cooker 10 is plugged in, a
liquid crystal
thermometer, a temporal thermometer, a bi-metal mechanical thermometer, an
alcohol
thermometer, a resistance thermometer, a pyrometer, or any other temperature
sensing
device now known or hereafter developed. Generally, a capillary thermometer is
preferred
because it requires no power source whatsoever to display at least an
approximate
temperature of the food contents even when the slow cooker 10 is unplugged.
The use of
other temperature sensing devices as indicated above can be used so long as
they can
operate independent of the power source which powers the heating elements 38
associated
with the slow cooker 10, or which operate on a power source separate and apart
from the
power cord 59. This enables a user to monitor the temperature of the food
contents within
the present slow cooker 10 during the serving mode without continuously
heating the food
contents.
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As shown in FIG. 6, one embodiment of housing 12 may also include two or more
opposing legs 58 coupled to outer wall 30 of sidewall 20 for allowing a power
cord 59 to
be wrapped around the legs 58 and stored thereon. Moreover, FIG. 6 illustrates
a cooking
vessel 16 including a sidewall 112, a bottom wall 114, and an annular rim 116
defining an
open top 118. Sidewall 112 includes a sidewall inner surface 120 and a
sidewall outer
surface 122 defining a sidewall thickness therebetween. One embodiment of the
present
invention may include a cooking vessel 16 having a sidewall thickness that is
greater than
the sidewall thickness typically associated with cooking vessels used in the
art. For
example, one embodiment may include a sidewall thickness of about two-times
the
sidewall thickness of conventional slow cookers. An increase in sidewall
thickness may
reduce the rate at which the food contents within the cookware vessel 16 lose
heat when
no heat is being applied thereto by the heating element 38. Annular rim 116
may further
include a ledge 124 defined therein which may be a recess associated with a
portion of
inner surface 118. Ledge 124 may be configured to receive and support lid 18
as shown
and further described below.
Bottom wall 114 further includes a bottom inner surface 126 and a bottom outer
surface 128 defining a bottom thickness therebetween. One embodiment of
cooking
vessel 16 may include a thermometer engagement zone 130 wherein a portion of
engagement zone 130 may include a portion of bottom outer surface 128 being
recessed to
engage top cap 64. Alternatively, engagement zone 130 may be either flat or
include a
portion thereof projecting outwardly so as to be received by a complimentary
recess
associated with top cap 64. Further, in one embodiment, an air space 132 may
be present
between the inner walls 28 and 32 of housing 12 and the outer surfaces 122 and
128 of
cooking vessel 16.
As further illustrated in FIG. 6, lid 18 includes an outer surface 134, an
inner
surface 136, an annular rim 138, and a handle 140. Annular rim 138 of lid 18
is
configured to rest upon ledge 124 as shown. When annular rim 138 rests upon
ledge 124,
cooking vessel 16 is substantially enclosed thereby capturing heat and
moisture which
assist the cooking process.
Handle 140 may be coupled to or otherwise attached to the outer surface 134 of
lid
18 through the use of a fastener 144 which passes through an aperture 146
extending
through both inner surface 134 and outer surface 136 of lid 18 and which is
received into
CA 02805830 2013-02-11
handle 140 as shown. Another embodiment (not shown) may include a lid 18
having
handle 140 integrally formed therewith.
Lid 18 may further include a vent 148 as illustrated in FIG. 6. Vent 148 may
be
simply an opening (fixed or adjustable) for allowing vapor to escape
therethrough during
cooking, or for allowing a user to insert an instrument (not shown) such as a
temperature
probe or sensor to directly measure the temperature of the food contents
within the
cooking vessel 16 during cooking or during serving. Alternatively, vent 148
further
includes an elastomeric membrane 150 that is configured to provide a barrier
in lid 18 that
allows pressure to escape out of the enclosed cooking vessel 16 during cooking
when a
predetermined pressure is reached, or otherwise. The membrane 150 can also be
configured for allowing a user to insert an instrument (not shown) such as a
temperature
sensor (not shown) through vent 148. One embodiment of vent 148 is shown in
FIG. 7.
This embodiment includes vent 148 being configured to be a one-way valve
allowing
pressure to escape the enclosed cooking vessel 16. As shown, vent 148 may
include
membrane 150 having a pattern of slits 142 through membrane 150. Membrane 150
may
be fabricated from a material and thickness wherein membrane 150 only
displaces under a
predetermined level of pressure thereby allowing one or more slits 142 to open
and release
pressure within enclosed cooking vessel 16 when the predetermine pressure
level is
reached. Alternatively, any type of vent 148 now known or hereafter developed
may be
used in concert with lid 18, including one-way or two way valves, or any other
type of
vent.
Lid 18 may further include at least one latch 152 as best illustrated in FIG.
1. FIG.
1 illustrates two latches 152 at opposing sides of lid 18 proximate annular
rim 138. As
shown, latches 152 may include a handle 154 and a loop 156 wherein loop 156 is
configured to engage hooks 60 of housing 12 as shown. Loops 156 are secured
within a
recess 158 in hook 60 when handle 154 is in a raised position. As shown in
FIG. 1, when
handle 154 is levered downwardly, lid 18 is secured to cooking vessel 16 upon
ledge 124
and both are secured to housing 12 as shown.
In use, a user will place the food items desired to be cooked in cooking
vessel 16.
The user may place the food items in cooking vessel 16 with cooking vessel 16
either
inside or outside of housing 12. If the food items are placed in cooking
vessel 16 outside
housing 12, the user will nest cooking vessel 16 into housing 12 and housing
12 will
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receive cooking vessel 16 through the open top 24. In any event, when cooking
vessel 16
is received into housing 12, rim 116 of cooking vessel 16 bears upon rim 26 of
housing 12
thereby suspending cooking vessel 16 within housing 12. The weight of the
cooking
vessel 16 prevents it from being unwantingly removed from housing 12. Further,
when
cooking vessel 16 is received into housing 12, thermometer contact zone 130 of
bottom
wall surface 128 of cooking vessel 16 engages outer surface 84 of top wall 72
of top cap
64 as shown in FIG. 6. As a result, capillary fluid reservoir 106 is in
thermal
communication with bottom surface 128 of cooking vessel 16.
In one embodiment, a user will use on/off switch 46 to turn the slow cooker on
and
employ cooking mode switch 52 to select a cooking temperature and a cooking
time. The
food product will cook at the preset cooking temperature for the preset
cooking time.
During the cooking stage, the fluid within capillary fluid reservoir 106 will
heat up and
expand thereby exerting a pressure upon the spring dial 55 of food temperature
indicator
54 resulting in a visual temperature indication of "hot."
If a user desires to serve the food items contained inside the slow cooker 10,
the
slow cooker 10 can be unplugged and moved to another location for serving, or
the on/off
switch can simply be turned off While unplugged or in its off condition, the
fluid within
the capillary fluid reservoir 106 will continue to measure the temperature of
the bottom
wall surface 128 of cooking vessel 16. Once heating has stopped, either by
turning the
slow cooker 10 off or unplugging it, thermometer 14 will provide the user with
at least an
estimated or approximate indication of the temperature of the food contents in
cooking
vessel 16.
Thermometer 14 measures the actual temperature of the exterior of cooking
vessel
16 at a specific wall location for furthering estimating and displaying the
approximate
food temperature inside cooking vessel 16. Capillary thermometer 14 is
connected to a
food temperature indicator 54 positioned in control panel 44 or elsewhere on
the front of
the slow cooker housing 12. Food temperature indicator 54 indicates whether
the food in
cooking vessel 16 is hot, cool, or is in some range between hot and cool. This
information
is useful for determining whether the food inside cooking vessel 16 has cooled
such that
re-heating may be warranted. Food temperature indicator 54 is calibrated to
account for
the differential between the actual temperature of the food product within the
cooking
vessel 16 and the measured temperature on the exterior 122 and/or 128 of
cooking vessel
12
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=
16 as measured by the capillary thermometer 14. The relationship between the
temperature of the food product at the center of cooking vessel 16 and the
exterior surface
122 or 128 of cooking vessel 16 can be experimentally observed and obtained as
set forth
in Table 1 below.
Time After Heat Temperature of
Temperature of Center Difference
Removed (minutes) Bottom Surface of of Stoneware Vessel ( C)
Stoneware Cooking ( C)
Vessel ( C)
0 120.0 100 -20
104.0 100 -4
89.0 97.7 8.7
(1/2 hr) 82.0 94.8 12.8
80.0 91.9 11.9
78.0 89.7 11.7
(1 hr) 76.0 87.3 11.3
73.0 85.0 12.0
70. 82.9 12.9
(1 1/2 hrs) 69.0 81.4 12.4
100 68.0 79.1 11.1
110 67.0 77.3 10.4
120 (2 hrs) 66.0 75.4 9.4
130 65.0 73.5 8.5
140 63.0 72.9 9.9
150 (2 1/2 hrs) 62.0 71.3 9.3
160 61.0 70.1 9.1
170 60.0 68.8 8.8
180 (3 hrs) 59.0 67.9 8.9
190 58.0 66.6 8.6
200 57.0 65.5 8.5
210 (3 1/2 hrs) 56.0 64.3 8.3
220 55.0 63.0 8.0
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230 54.0 62.0 8.0
240 (4 hrs) 53.0 60.7 7.7
Average 8.17
Table 1. Temperature of Bottom of Cooking Vessel and Center of Stoneware
Vessel
versus Time After the Heat Source Has Been Removed.
Experimental values of the temperature differential between the actual
temperature
of the food within cooking vessel 16 and the measured temperature of bottom
wall 128 of
cooking vessel 16 after heating elements 38 were turned off are shown in Table
1 above.
For example, after the first ten minutes, the temperature differential between
the actual
temperature of the food within cooking vessel 16 and the measured temperature
on
exterior surface 128 of cooking vessel 16 was 4 C. After four (4) hours with
no heat
applied to the cooking vessel 16, the temperature differential was mostly in a
range
between about 8 C to about 13 C with the average temperature differential
being around
8.2 C. As such, a correlation temperature offset of 8 C (correlation factor)
could be used
to calibrate the dial indicator 55 to the approximate temperature of food
product within the
cooking vessel 16.
Thus, the approximate temperature of the food product within vessel 16 may be
visually determined at all times during the serving process, that is, cool,
hot, or somewhere
in between. If food temperature dial 55 moves toward the "cool" end of the
dial, a user
may then plug-in or otherwise turn-on heating elements 38 of housing 12 to re-
heat the
food contents. Thus, a user will always have a visual indicator of the
temperature of the
food contents using slow cooker 10 of the present invention.
Although it is preferred that the thermometer 14 be a capillary thermometer as
disclosed above and illustrated in FIGS. 4 and 6, it is recognized that other
types of
thermometers as discussed above can likewise be utilized in the present
invention so long
as the thermometer is able to read and correlate at least an approximate
temperature of the
food product being cooked within the cooking vessel 16 when the slow cooker 10
is
disconnected from its power source. In those instances where the thermometer
requires a
power source, a portable or replaceable power source such as batteries or
other power
means unrelated to the power source powering the slow cooker 10 such as power
cord 59
14
CA 02805830 2013-02-11
can be utilized to power the thermometer 14 when the slow cooker 10 is
unplugged and is
being utilized in its serving mode. It is also recognized and anticipated that
other fluids
besides kerosene can be utilized with a capillary thermometer as discussed
above. Still
further, it is also recognized and anticipated that the overall dimensions of
the present slow
cooker 10 including the thermometer 14, the housing assembly 62, and the
overall
configuration of the temperature sensing device 61 as well as the specific
shape and
configuration of these members are subject to wide variations and may be sized
and
shaped into a wide variety of different sizes and configurations so as to be
compatible with
the size and shape of a particular slow cooker assembly, or to conform with
any space
limitations associated therewith. Other variations and modifications to the
various
components comprising the present structures are also contemplated.
Thus, there has been shown and described several embodiments of a novel slow
cooker with a thermometer for indicating a temperature condition of the food
product
contained in the cooking vessel, which slow cooker fulfills all of the objects
and
advantages sought therefor. Many changes, modifications, variations and other
uses and
applications of the present invention will, however, become apparent to those
skilled in the
art after considering this specification and the accompanying drawings. The
scope of the
claims should not be limited by particular embodiments set forth herein, but
should be
construed in a manner consistent with the specification as a whole.
