U.S. patent application number 13/989473 was filed with the patent office on 2013-12-19 for heat sealer with algorithm for regulating sealing temperature.
This patent application is currently assigned to Sunbeam Products, Inc.. The applicant listed for this patent is Landen Higer, Zhu Liu, Terry Sun, Francis Wong. Invention is credited to Landen Higer, Zhu Liu, Terry Sun, Francis Wong.
Application Number | 20130333336 13/989473 |
Document ID | / |
Family ID | 46146418 |
Filed Date | 2013-12-19 |
United States Patent
Application |
20130333336 |
Kind Code |
A1 |
Liu; Zhu ; et al. |
December 19, 2013 |
Heat Sealer with Algorithm for Regulating Sealing Temperature
Abstract
A vacuum and sealing appliance comprises a heat sealing element
for sealing a container during a sealing cycle. A controller
controls the temperature of the heat sealing element during the
sealing cycle based on a signal from a temperature sensor that
senses the real-time temperature of the heat sealing element. A
seal indicator light is provided which is lighted during the
sealing cycle and extinguished at its completion. The signal from
the controller energizes the heating element for a time to heat the
sealing element to a pre-determined temperature for sealing the
container and initiates a dwell time corresponding to cooling the
heating element after sealing the container. Values of the
real-time temperatures of the heat sealing element and values of
the sealing times and the dwell times that correspond to the values
of the real-time temperatures of the heat sealing element are
stored in a look-up table.
Inventors: |
Liu; Zhu; (Dongguan City,
CN) ; Sun; Terry; (Dongguan City, CN) ; Wong;
Francis; (Dongguan City, CN) ; Higer; Landen;
(Alameda, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Liu; Zhu
Sun; Terry
Wong; Francis
Higer; Landen |
Dongguan City
Dongguan City
Dongguan City
Alameda |
CA |
CN
CN
CN
US |
|
|
Assignee: |
Sunbeam Products, Inc.
Boca Raton
FL
|
Family ID: |
46146418 |
Appl. No.: |
13/989473 |
Filed: |
November 23, 2011 |
PCT Filed: |
November 23, 2011 |
PCT NO: |
PCT/US11/62030 |
371 Date: |
July 25, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12953637 |
Nov 24, 2010 |
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13989473 |
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10897327 |
Jul 21, 2004 |
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12953637 |
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60491876 |
Jul 31, 2003 |
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Current U.S.
Class: |
53/507 ;
53/370.7; 53/512 |
Current CPC
Class: |
B65B 57/18 20130101;
B29C 66/861 20130101; B29C 65/224 20130101; B29C 66/8324 20130101;
B29C 66/91211 20130101; B29C 66/7373 20130101; B29C 66/91445
20130101; B29C 66/91935 20130101; B29C 66/949 20130101; B29C 66/961
20130101; B29C 66/1122 20130101; B29C 66/00145 20130101; B65B
51/146 20130101; B29C 65/223 20130101; B29C 66/91423 20130101; B29C
66/91231 20130101; B29C 66/91421 20130101; B65B 31/00 20130101;
B29C 66/8748 20130101; B29C 66/8491 20130101; B29C 66/919 20130101;
B29L 2031/7128 20130101; B29C 66/91641 20130101; B65B 31/048
20130101; B29C 66/8221 20130101; B29C 66/81811 20130101; B29C
66/9121 20130101; B29C 66/91431 20130101; B29C 66/232 20130101;
B29C 66/43121 20130101; B29C 66/91655 20130101 |
Class at
Publication: |
53/507 ;
53/370.7; 53/512 |
International
Class: |
B65B 51/14 20060101
B65B051/14; B65B 57/18 20060101 B65B057/18; B65B 31/00 20060101
B65B031/00 |
Claims
1. A sealing appliance having a controller performing a method of
sealing, the method comprising the steps of: sensing with a sensor
a first temperature of at least one heat sealing element;
determining an actuation control signal based on the first
temperature for use during a sealing operation cycle, the sealing
operation cycle including at least a sealing time corresponding to
energizing and heating the at least one heat sealing element to a
predetermined temperature for sealing a container and a dwell time
corresponding to cooling of the at least one heating element after
sealing the container; and extinguishing a seal indicator light
when the sealing operation cycle is complete; whereby values of the
first temperatures of the at least one sealing element and values
of the sealing times and the dwell times that correspond to the
values of the first temperatures are stored in a look-up table.
2. The sealing appliance of claim 1, wherein the look-up table
corresponds to values of first temperatures, sealing times and
dwell times for an alternating current power source.
3. The sealing appliance of claim 1, wherein the look-up table
corresponds to values of initial temperatures, sealing times and
dwell times for a direct current power source.
4. The sealing appliance of claim 1, wherein the sealing operation
cycle includes the step of evacuating a container placed into the
sealing appliance.
5. The sealing appliance of claim 1, wherein the sealing operation
cycle is commenced when a seal button is depressed.
6. The sealing appliance of claim 1, wherein a vacuum and sealing
operation cycle is commenced when a seal and vacuum button is
depressed.
7. The sealing appliance of claim 1, the method further including
the step of lighting a ready indicator light after the sealing
operation has been completed and the seal indicator light has been
extinguished.
8. A vacuum and sealing appliance, comprising: a least one heat
sealing element for sealing a vacuum packaging container placed in
the vacuum and sealing appliance during at least one sealing cycle;
a temperature sensor for sensing a first temperature of the at
least one sealing element prior to the beginning of the at least
one sealing cycle; a heat sealing element controller that controls
the temperature of the at least one heat scaling element during the
at least one sealing cycle based on a signal from the temperature
sensor; a seal indicator light which is lighted during the at least
one sealing cycle and extinguished at the completion of the at
least one sealing cycle; wherein the signal from the controller
energizes the heating element for a first time to heat the at least
one heat sealing element to a pre-determined temperature for
sealing the vacuum packaging container and a dwell time
corresponding to cooling of the at least one heating element after
sealing the vacuum packaging container, and values of the first
temperatures of the at least one heat sealing element and values of
the sealing times and the dwell times that correspond to the values
of the first temperatures are stored in a look-up table.
9. The heat sealing device of claim 8, wherein the look-up table
corresponds to values of first temperatures, sealing times and
dwell times for an alternating current power source.
10. The heat sealing device of claim 8, wherein the look-up table
corresponds to values of initial temperatures, sealing times and
dwell times for a direct current power source.
11. A sealing appliance including a controller performing a method
of sealing, the method comprising the steps of: sensing with a
first sensor a first temperature of at least one heat sealing
element; sensing with a second sensor a second temperature of a
base of the sealing appliance; determining whether the first
temperature of the at least one heat sealing element is below a
first threshold temperature and whether the second temperature of
the base is below a second threshold temperature; disabling all
vacuum and sealing operation keys if both the first temperature of
the at least one heat sealing element is not below the first
threshold temperature and the second temperature of the base is not
below a second threshold temperature and flashing a seal indicator
light; initiating a sealing operation cycle if both the first
temperature of the at least one heat sealing element is below the
first threshold temperature and the second temperature of the base
is below a second threshold temperature and lighting the seal
indicator light, the sealing operation cycle including: determining
an actuation control signal based on the sensed first temperature
of the heat sealing element for use during the sealing operation
cycle, the sealing operation cycle including at least a sealing
time corresponding to energizing and heating the at least one heat
sealing element to a pre-determined temperature for sealing a
container and a dwell time corresponding to cooling of the at least
one heating element after sealing the container; and extinguishing
the seal indicator light when the sealing operation cycle is
complete; whereby values of the initial temperatures of the at
least one sealing element and values of the sealing times and the
dwell times that correspond to the values of the initial
temperatures are stored in a look-up table.
12. The sealing appliance of claim 11, the method further including
selecting the first threshold temperature to be 75.degree. C.
13. The sealing appliance of claim 11, the method further including
selecting the second threshold temperature to be 65.degree. C.
14. The sealing appliance of claim 11, the method further including
lighting a ready indicator light after the sealing operation has
been completed and the seal indicator light has been
extinguished.
15. The sealing appliance of claim 14, wherein the ready indicator
light is green when lighted.
16. The sealing appliance of claim 11, wherein a sealing operation
cycle is commenced when a seal button is depressed.
17. The sealing appliance of claim 11, wherein a vacuum and sealing
operation cycle is commenced when a seal and vacuum button is
depressed.
18. The sealing appliance of claim 11, wherein the seal indicator
light flashes red when the vacuum and sealing operation keys are
disabled if both the first temperature of the at least one heat
sealing element is not below the first threshold temperature and
the second temperature of the base is not below a second threshold
temperature.
19. The sealing appliance of claim 11, wherein the look-up table
corresponds to values of first temperatures, sealing times and
dwell times for an alternating current power source.
20. The sealing appliance of claim 11, wherein the look-up table
corresponds to values of first temperatures, sealing times and
dwell times for a direct current power source.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a heat sealer, and more
particularly to, a heat sealer utilizing an algorithm to regulate
the sealing temperature.
BACKGROUND OF THE INVENTION
[0002] Presently, various appliances and methods are used for the
purpose of vacuum sealing plastic bags and containers to protect
perishables, such as foodstuffs, and other products against
oxidation. Conventional commercial appliances and some consumer
appliances are generally expensive to manufacture, complex in
construction and/or cumbersome to operate. There are also different
types of heat sealing mechanisms contained in these prior art
devices that have limited success in hermetically sealing the
evacuated bags.
[0003] One type of conventional vacuum sealing appliances uses a
vacuum nozzle that is inserted within a plastic bag for evacuation
purposes. Although adaptable for low-volume home use, this type of
system is cumbersome to use and normally requires a liquid
separator or filter to prevent liquids or powders, retained within
the bag, from being drawn into a vacuum pump connected to the
nozzle. Further, a heat sealer employed therein must be closely
synchronized with the positioning and withdrawal of the vacuum
nozzle from the bag. This greatly adds to the cost and complexity
of the device itself.
[0004] U.S. Pat. No. 3,928,938 discloses another type of vacuum
sealing appliance that employs a heat sealing mechanism. In this
appliance a user places a portion of a bag, containing a product to
be packaged, in a first vacuum chamber and extends an open end or
neck of the bag into a second vacuum chamber. The first vacuum
chamber is then evacuated to expand the neck of the bag to isolate
the chambers from each other. Then a vacuum is drawn in the second
vacuum chamber to evacuate the bag. Thus, isolation of the two
chambers from each other, during evacuation of the second vacuum
chamber, is dependent on the physical properties composing the neck
of the bag and very close synchronization and calibration of the
evacuation and sealing procedures and controls therefore. This
complex process in conjunction with the heat sealing mechanism is
not reliable.
[0005] These prior art appliances described above and others
require the use of special bags that must be purchased from the
manufacturer. Due to the cost of the vacuum useable bags, it is
desirable to conserve the material as much as possible. One problem
with the above appliances is that there is a substantial amount of
wasted vacuum bag material between the end of the bag and the heat
seal as shown in Prior Art FIG. 12. FIG. 12 shows a container 20,
with heat seals 21 and 22. For example, the vacuum sealed container
20 of FIG. 12 may be approximately 10 inches in length. The length
between the end of the container 20 and each heat seal (21 and 22)
is approximately an inch and a half. Therefore 3 inches of bag
material is essentially unused for a 10 inch vacuum sealed bag.
Therefore prior art devices waste approximately 30% of the vacuum
bag material per use.
[0006] Another problem with prior art vacuum packaging appliances
is that the temperature of the heat sealing mechanism is not
accurately controlled. This is because the prior art appliances use
a simple on/off time switch to excite the heat sealing elements.
Under the heat seal control mechanism of the prior art, sealing
multiple bags without allowing the heat sealing element to cool
results in bags beginning to seal before the vacuum process is
complete. This causes ineffective seals and prevents complete
evacuation of gas from the bags, that results in expensive
packaging bag waste. Further, activating the elements without
considering real-time temperature may cause damage to the appliance
due to element overheating.
[0007] Therefore there exists a need for a vacuum packaging
appliance that accurately controls the temperature of the heat
sealing elements and optimizes the placement of the heat sealing
elements within the appliance.
SUMMARY OF THE INVENTION
[0008] In an embodiment, there is provided a sealing appliance
including a controller performing a method of sealing, the method
comprising the steps of: sensing with a sensor a first temperature
of at least one heat sealing element, determining an actuation
control signal based on the first temperature for use during a
sealing operation cycle, the sealing operation cycle including at
least a sealing time corresponding to energizing and heating the at
least one heat sealing element to a pre-determined temperature for
sealing a container and a dwell time corresponding to cooling of
the at least one heating element after sealing the container, and
extinguishing a seal indicator light when the sealing operation
cycle is complete, whereby values of the first temperatures of the
at least one sealing element and values of the sealing times and
the dwell times that correspond to the values of the first
temperatures are stored in a look-up table.
[0009] In another embodiment, there is provided a vacuum and
sealing appliance comprising a least one heat sealing element for
sealing a vacuum packaging container placed in the vacuum and
sealing appliance during at least one sealing cycle, a temperature
sensor for sensing a first temperature of the at least one sealing
element prior to the beginning of the at least one sealing cycle, a
heat sealing element controller that controls the temperature of
the at least one heat sealing element during the at least one
sealing cycle based on a signal from the temperature sensor, a seal
indicator light which is lighted during the at least one sealing
cycle and extinguished at the completion of the at least one
sealing cycle, wherein the signal from the controller energizes the
heating element for a first time to heat the at least one heat
sealing element to a pre-determined temperature for sealing the
vacuum packaging container and a dwell time corresponding to
cooling of the at least one heating element after sealing the
vacuum packaging container, and values of the first temperatures of
the at least one heat sealing element and values of the sealing
times and the dwell times that correspond to the values of the
first temperatures are stored in a look-up table.
[0010] In another embodiment, there is provided a sealing appliance
including a controller for performing a method of sealing, the
method comprising the steps of: sensing with a first sensor a first
temperature of at least one heat sealing element, sensing with a
second sensor a second temperature of a base of the sealing
appliance, determining whether the first temperature of the at
least one heat sealing element is below a first threshold
temperature and whether the second temperature of the base is below
a second threshold temperature, disabling all vacuum and sealing
operation keys if both the first temperature of the at least one
heat sealing element is not below the first threshold temperature
and the second temperature of the base is not below a second
threshold temperature and flashing a seal indicator light,
initiating a sealing operation cycle if both the first temperature
of the at least one heat sealing element is below the first
threshold temperature and the second temperature of the base is
below a second threshold temperature and lighting the seal
indicator light. The sealing operation cycle includes the step of
determining an actuation control signal based on the sensed first
temperature of the heat sealing element for use during the sealing
operation cycle, the sealing operation cycle including at least a
sealing time corresponding to energizing and heating the at least
one heat sealing element to a pre-determined temperature for
sealing a container and a dwell time corresponding to cooling of
the at least one heating element after sealing the container, and
the step of extinguishing the seal indicator light when the sealing
operation cycle is complete, whereby values of the initial
temperatures of the at least one sealing element and values of the
sealing times and the dwell times that correspond to the values of
the initial temperatures are stored in a look-up table.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A more complete understanding of the present invention, and
the attendant advantages and features thereof, will be more readily
understood by reference to the following detailed description when
considered in conjunction with the accompanying drawings
wherein:
[0012] FIG. 1 is an isometric view of one embodiment of the vacuum
packaging apparatus of the invention with the lid in a closed
position.
[0013] FIG. 1A is an isometric view of an alternate embodiment of
the vacuum packaging apparatus of the invention with the lid in a
closed position.
[0014] FIG. 2 is an isometric view of the underside of the
apparatus shown in FIG. 1.
[0015] FIG. 2A is an isometric view of the rear of the apparatus
shown in FIG. 1A.
[0016] FIG. 2B is an isometric view of a DC power adapter for use
with the apparatus shown in FIGS. 1A and 2A.
[0017] FIG. 3 is an expanded isometric view of the control panel of
the apparatus shown in FIG. 1.
[0018] FIG. 3A is an isometric view of the control panel of the
apparatus shown in FIGS. 1A and 2A.
[0019] FIG. 4 is an isometric view of the apparatus shown in FIG. 1
with the lid in an open position.
[0020] FIG. 5 is an isometric view of the apparatus shown in FIG. 1
with the lid in an open position and with the trough removed from
the apparatus.
[0021] FIG. 6 is an isometric view of the trough removed from the
apparatus.
[0022] FIG. 7 is transverse cross-sectional view of the device
shown in FIG. 1.
[0023] FIG. 8 is another embodiment of a transverse cross-sectional
view of the device shown in FIG. 1.
[0024] FIG. 8A is another embodiment of the heat sealing element
wires.
[0025] FIG. 9 is schematic diagram of the control circuitry of the
heat sealing element.
[0026] FIG. 10 is a flowchart showing method steps of the present
invention.
[0027] FIG. 11 shows a vacuum sealed bag in accordance with the
present invention.
[0028] FIG. 12 shows a Prior Art vacuum sealed bag.
[0029] FIG. 13 is a flowchart showing method steps of the present
invention.
[0030] FIG. 14 is a flowchart showing method steps of the present
invention.
[0031] FIG. 15 is a flowchart showing method steps of the present
invention.
[0032] FIG. 16 is a flowchart showing method steps of the present
invention.
[0033] FIG. 17 is a flowchart showing method steps of the present
invention.
[0034] FIG. 18 is a flowchart showing method steps of the present
invention.
[0035] FIG. 19 is a flowchart showing method steps of the present
invention.
[0036] FIG. 20 is a flowchart showing method steps of the present
invention.
[0037] FIG. 21 is a flowchart showing method steps of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0038] The present invention sets forth several embodiments
relating to the position and control of heat sealing elements
within vacuum packaging appliances.
[0039] The heat sealing element may be mounted on the lid or the
base of the appliance. The placement of the heat sealing element
within the appliance minimizes wasted bag material, as the heat
seal is placed closer to the end of the bag itself. The present
invention also includes a heat sealing controller that may adjust
the amount of current applied to the heat sealing element based on
a number of different inputs. It will be understood by those
skilled in the art that the description of the methods and
structures of the vacuum packaging appliance described below is not
intended to be limiting in anyway.
[0040] FIG. 1 shows a vacuum packaging appliance 100 for vacuum
packaging articles in a container. The vacuum packaging appliance
100 has a lid 102 and a base 104 that are pivotally connected at a
back side 106 of the appliance 100. The lid includes a blade handle
108 that is associated with a blade (not shown) that is slideably
engaged within a slot 110 that extends substantially the entire
length of the vacuum packaging appliance 100. The blade is for
cutting sections of flexible vacuum bag material that may be stored
inside the appliance 100.
[0041] FIG. 1 also shows that the base 104 of the vacuum packaging
appliance 100 includes an aperture 112 that is covered by a door
114. The door 114 is slideably mounted in the interior of the base
104 and includes a protrusion 116 that allows a user to more easily
slide the door 114 between an open and closed position. A trough
for collecting debris may be placed into the appliance 100 through
this door 114. A control panel 118 is coupled with the base 104 and
extends above the lid 102. As will be described with reference to
FIGS. 3 and 9, the control panel 118 provides and allows operator
input to control the heat sealing process of the vacuum packaging
appliance 100.
[0042] FIG. 1A shows an alternate embodiment of a vacuum packaging
appliance 150 similar to the vacuum packaging appliance 100 above.
A control panel 168 is disposed on a base 155 adjacent a lid 152.
The lid 152 is pivotally mounted to the base 155 at the backside of
the appliance 150. As will be described with reference to FIGS. 3A
and 9, the control panel 168 provides and allows operator input to
control the heat sealing process of the vacuum packaging appliance
150. There is a slot 160 between the lid 152 and the base 155 where
a container 20 (FIG. 12) may be inserted for sealing by heating
elements 420 controlled by a controller 92 (FIG. 9). There is also
a port 175 for attaching a tube for evacuating an external
container (not shown).
[0043] FIG. 2 is an isometric view of the underside of the vacuum
packaging appliance 100. The vacuum packaging appliance 100
includes an alternating current (AC) power cord 202 that is coupled
with the base 104. The base 104 also has a recess 204 for storage
of the power cord 202. To at least partially retain the power cord
in the recess 204, the base also includes cord retention flanges
206. In the embodiment shown in FIG. 2, the power cord 202 will
supply electrical power to the heating elements and the vacuum pump
of the vacuum packaging appliance 100.
[0044] Optionally, in the alternate embodiment of the vacuum
packaging appliance 150 shown in FIG. 2A, in addition to an
alternating current (AC) power cord 202 (not shown) a direct
current (DC) power cord 220 (FIG. 2B) may be provided to supply
electrical power to the heating elements and the vacuum pump of the
vacuum packaging appliance 150. The power cord 220 includes a plug
221 on a first end that plugs into an outlet 215 (FIG. 2A) disposed
in the base 155. A second end of the power cord 220 connects to a
source of DC power such as a 12 volt cigarette lighter outlet in an
automobile. The power cord 220 may include on the second end a
cigarette lighter adapter 223 that plugs into the cigarette lighter
outlet in the automobile.
[0045] FIG. 3 is a magnified view of the control panel shown in
FIG. 1. The control panel 118 has a face plate 302 that is
removably coupled with the base 104. The control panel 118 has a
rotary dial 304, a cancel control button 306, an instant seal
button 308, an extended vacuum control button 310, an accessory
port 312 and an indicator light 314. In alternate embodiments,
various other controls maybe included in the control panel 118
and/or various controls maybe excluded from the control panel
118.
[0046] The rotary dial 304 has multiple positions that can control
various aspects of the vacuum packaging appliance 100, for example:
"Accessory", 1, 2, 3 and "Seal Only". However in other embodiments,
the rotary dial may have more or fewer settings that can control
various aspects of the vacuum packaging appliance 100. When the
rotary dial 304 is in the accessory position, the accessory port
312 is activated and accessories (not shown) can be attached to the
vacuum packaging appliance 100 either directly or via a vacuum
hose. When the rotary dial 304 is in any position other than the
accessory position, the accessory port 312 is sealed off and a
vacuum is not drawn through the accessory port 312.
[0047] Positions 1, 2 and 3 of the rotary dial 304 allow the user
to control the duration of the evacuation process and the length of
time the heat sealing element is activated. Position 1 may activate
the sealing mechanism for a first predetermined period producing a
light seal. Position 2 may activate the sealing mechanism for a
second predetermined period producing a medium heat seal, and
position 3 may activate the sealing mechanism for a third
predetermined period resulting in a heavy heat seal. Position 1
would correspond to a fragile content mode, wherein an actuation
control signal would have a sealing time period shorter than a
normal content mode sealing time period. Thus, the user can select
the duration of the sealing process. For example sealing potato
chips or fruit may require a fragile or light seal; whereas sealing
meat would require a heavy seal. The seal only position allows a
user to use the apparatus to operate a sealing mechanism only,
without requiring evacuation of a primary evacuation chamber.
[0048] Although the apparatus shown in FIG. 3 includes a rotary
dial 304 with five positions, in alternate embodiments the
apparatus can include a rotary dial 304 that has more or fewer
positions. For example a "smart seal" setting may be included. When
the "smart seal" is selected the appliance automatically controls
the current to the heat sealing elements in accordance with the
actual element temperature. After repetitive uses the heat sealing
elements may become hot; therefore it requires less electrical
power to heat the sealing elements to a sealing temperature. The
control of the heat sealing elements is described below with
reference to FIG. 9.
[0049] The cancel button 306 allows a user to cancel a vacuum
operation or sealing operation at any time during the operation.
The instant seal button 308 allows a user to terminate the
evacuation process and begin the sealing process at any time during
operation of the vacuum packaging appliance 100. The extended
vacuum button 310 allows a user to extend the length of time for
which the container (not shown) is evacuated. The accessory port
312 allows a user to connect the apparatus to various containers as
described in U.S. Pat. No. 4,491,310, by Harms J. Kristen, issued
Jul. 17, 1990, and assigned to the same assignee as this patent
application, the complete contents of which is incorporated herein
by reference.
[0050] The indicator light 314 serves to notify a user of the
status of the vacuum packaging appliance 100. In the embodiment
shown in FIG. 3, the indicator light is off when the device is
inactive, solid green while the device is actively evacuating a
container and emits intermittent green flashes when the device is
sealing a container. However, in alternate embodiment the light may
emit light of various colors and/or intensities and/or at various
intervals to indicate various operations that the machine is
performing. For example, the indicator light 314 may flash amber or
some other color to indicate that the device is currently drawing
an extended vacuum or the indicator light 314 may glow red to
indicate that the accessory port 312 is active.
[0051] In still further alternate embodiments, the control panel
118 may not include an indicator light 314.
[0052] In the alternate embodiment of the vacuum packaging
appliance 150 shown in FIG. 3A, the rotary dial 304 has been
replaced with a single seal button 370 on a control panel 168
similar to the "smart seal" button above for controlling the
current to the heat sealing elements.
[0053] There is also on the control panel 168 a seal and vacuum
button 372 and a plurality of indicator lights 381-385 which may be
light emitting diodes (L.E.D.'s). The indicator lights 381-385 emit
a solid green light to indicate the progress of the vacuum
operations. A lever 375 is provided which is moveable between a
first open position to a second position to latch the lid 152
closed to perform the vacuum and sealing operations. A ready
indicator light 380 is provided to indicate that the lid 152 is
latched in the closed position. The ready indicator light 380 emits
a solid green light to indicate that the appliance 150 is ready to
perform vacuum and scaling operations. A seal indicator light 386
indicates when the sealing operation is being performed on the
container 20 by emitting a steady red light which is extinguished
when the sealing operations are completed and the sealed container
20 may be removed from the appliance 150. The control of the heat
sealing elements is described below with reference to FIG. 9.
[0054] FIG. 4 is an isometric view of the apparatus 100 shown in
FIG. 1 with the lid 102 in an open position. The lid 102 includes a
primary evacuation chamber 408 that is surrounded by a flexible
gasket 406. The primary evacuation chamber 408 is coupled to a
vacuum source housed inside the vacuum packaging appliance 100. The
lid also includes a heat sealing element 433. The heat sealing
element 433 touches electrical contacts 431 and 432 on the base of
the device when the lid is closed. In this manner power is supplied
to the heat sealing element via the contacts. This is desirable, as
no power cord is necessary to run through the device hinges into
the lid 102. This reduces the complexity of the device itself. In
alternate embodiments, the heat sealing element may be 2 wires or a
wider element to ensure a proper heat seal.
[0055] The base 104 of the vacuum packaging appliance 100 includes
an electromechanical switch 416, positioned on the base such that
when the lid 102 is in a closed position, the protrusion 414 is
substantially vertically aligned with the electromechanical switch
416. Thus, when the lid 102 is in a closed position and then is
further depressed, the protrusion 414 can actuate the
electromechanical switch 416 and activate the vacuum packaging
appliance 100.
[0056] The base 104 of the vacuum packaging appliance 100 shown in
FIG. 4 has a recess 422 that is adapted to hold container material
424. The vacuum packaging container material 424 is a roll of
flattened, tubular container material and is supported on
rotational supports 426.
[0057] The rotation supports 426 are designed to engage the ends of
the roll of container material 424 and rotate freely within the
recess 422. In a further embodiment, the roll or container material
424 may simply be place or stored in the recess 422 without any
support mechanism to facility dispensing the container material
424.
[0058] The roll of container material may be a single roll of
continuously bonded plastic as described in U.S. Pat. No. RE34,929,
by Hanns J. Kristen, issued May 9, 1995 a reissue patent based on
U.S. Pat. No. 4,756,422, by Hanns J. Kristen, issued Jul. 12, 1988,
assigned to the assignee of the present application, the complete
contents of which is incorporated herein by reference. However, in
alternate embodiments, the roll of container material 424 may be
any convenient material.
[0059] The thermal sealing mechanism 433 includes one or more
electrically conductive wires that produce heat when a voltage
differential is applied across the length of the wire. In the
embodiment shown, the electrically conductive wires are covered
with a Teflon tape.
[0060] However, in alternate embodiments, the wires maybe exposed
or wrapped in a material. If the sealing mechanism 433 is activated
and container material 424 is disposed between the sealing gasket
406 and the sealing mechanism 433, the container material 424 can
be hermetically sealed. Although the apparatus 100 is described as
including a sealing mechanism 433 that is integrated with the
apparatus, in alternate embodiments, the sealing mechanism 433 may
be on the base of the device while the electrical contacts are
located on the lid. Additionally in alternate embodiments, various
other placements of the heat sealing mechanisms 433 may be employed
in order to seal the container material 424.
[0061] In operation, when the lid 102 is in a closed position and
is depressed such that the protrusion 414 actuates the
electromechanical switch 416, the vacuum pump or source is
activated. Evacuation of the primary evacuation chamber 404 and
trough 430 is then performed. When the lid 102 is in a closed
position, the gasket 406 surrounding the primary evacuation chamber
408 and the trough 430 are substantially vertically aligned such
that a vacuum circuit is obtained or formed.
[0062] For cleaning purposes, the trough 430 is removable from the
base 104 of the vacuum packaging appliance 100 through the aperture
112 when the door 114 is in an open position. In the embodiment
shown in FIG. 4 the door 114 is manually slideable between and open
and a closed position. However, in alternate embodiments, the door
can be mechanically operated and/or can open in any convenient
fashion. In still further alternate embodiments, the door 114 may
not be present.
[0063] In operation, a user inserts an open end of a container 20,
such as a flexible bag, into the trough 430 or attaches a container
to the accessory port 312. The user then selects a setting on the
rotary dial 304, closes the lid 102 and depresses the lid 102 past
the closed position to actuate the electromechanical switch 416
with the protrusion 414. The vacuum source 434 will then evacuate
the latch chambers 402 to hold the lid 102 relative to the base
104. Once the lid 102 is secured relative to the base 104, the
primary evacuation chamber 408 and the trough 430 are evacuated
thus evacuating the open container inserted into the appliance 100.
When the vacuum strength reaches a predetermined level, the sealing
mechanism 433 will be activated to seal the container. The
evacuated and sealed container may then be released from the vacuum
packaging appliance 100.
[0064] FIG. 5 is an isometric view of the apparatus shown in FIG. 4
with the trough 430 removed and the door 114 in an open position.
The embodiment shows a recess 502 in which the trough 430 may be
inserted and removed. The recess 502 has retention flanges 504 that
are designed to prevent substantial vertical and rotational
movement of the trough 430 within the recess 502. The recess 502
has a slot 506 at the end of the recess 502 opposite the door 114.
The slot 506 is designed to mate with a protrusion in the trough
430 in a snap-fit manner. The snap-fit mating of the slot 506 and
the recess in the trough 430 is designed to restrict horizontal
movement of the trough 430 within the recess 502.
[0065] FIG. 6 is an isometric view of the trough 430. The trough
430 includes an extension that includes a protrusion 602. The
protrusion 602 is designed to mate with the slot 506 in a snap-fit
manner. The embodiment shown in FIG. 6 includes flanges 604 that,
as described with reference to FIG. 5, are designed to engage with
the retention flanges 504. The embodiment shown in FIG. 6 also
includes a handle 606. The handle is included to facilitate removal
and insertion of the trough 430.
[0066] FIG. 7 is a sectional view of the apparatus shown in FIG. 1,
cut along the section line A-A. FIG. 7 shows the lid 102 in a
closed position relative to the base 104. The base 104 includes the
thermal sealing mechanism 420 that is positioned in substantial
vertical alignment with the sealing gasket 406 in the lid 102 of
the appliance. When the lid 102 is in a closed position relative to
the base 104, the gasket 406 that surrounds the primary evacuation
chamber 408 and the trough 430 are in substantial vertical
alignment and are in contact, thus defining an evacuation chamber.
The embodiment shown in FIG. 7 also shows a roll of container
material 424 that is stored within the appliance 100, and a vacuum
pump 434.
[0067] The embodiment of FIG. 7 shows a heat sealing element 420
mounted adjacent to the trough 430. In operation, the element 420
receives electrical current from a power source or sources that
causes the element to heat up to temperatures exceeding 130 degrees
thereby heat sealing the vacuum bag. As the location of the heat
sealing element 420 is behind the gasket 406, this results in a
seal that is close to the bag edge which results in the
minimization of bag material necessary for packaging. Sensor 90 is
a temperature sensor and is located adjacent to the sealing
elements 420. Sensor 91 is a liquid sensor that senses the amount
and presence of liquid in the trough 430. Both of these sensors
feed signals back to a controller as shown in FIG. 9, that supplies
power via control signals to the heat sealing elements 420. The
present invention is described as a piston-type vacuum, however the
vacuum source 434 may be any convenient mechanism capable of
drawing a vacuum.
[0068] FIG. 8 shows a vacuum sealable container 804 being placed
into the appliance. In this embodiment the front side of the trough
430 includes the heat sealing elements 420 and an extension that
includes a protrusion 802. The protrusion 802 is designed to seal
the evacuation chamber and trough with the gasket 406. This view of
the appliance shows the vacuum chamber 430 and lid 102 in an open
position. A vacuum packaging bag 804 that is designed to be heat
sealed by elements 420 is placed into the front of the appliance by
the user. The gasket 406 is one continuous loop around the
rectangular trough and vacuum chamber 430. The front side of gasket
406 is wider than the back side of the gasket. The gasket 406 is
wider on the front side as the gasket 406 is performing multiple
functions and this ensures that a proper vacuum seal is
obtained.
[0069] As can be seen from FIG. 8, the gasket is used to create a
seal but also to hold the vacuum packaging receptacle 804 in
contact with the heat sealing elements 420 located adjacent to the
trough 430. The presence of the bag 804 also requires a wider
gasket 406 to ensure a proper seal. The back side of the gasket 406
does not perform multiple functions as the front side does,
therefore it may be smaller in width. The gasket 406 is also only
located on the lid 102 of the appliance. In this embodiment there
is no need for an additional gasket mounted around the trough in
the base of the appliance. This is another feature and advantage of
the present invention.
[0070] Also shown in FIG. 8 are valves 808 and 812 and passages 806
and 810. The valve 808 is electrically controlled (by a controller
as shown in FIG. 9) and is used to open and close an opening into a
passageway 806. When the valve 808 is opened, the exhaust from the
vacuum pump is directed through the passage 806. The passage runs
underneath the entire length of the heating elements 420. The
exhaust moving through the passage provides a cooling effect to
reduce the temperature of the elements 420. After the exhaust has
passed through the passage 806 and cooled the elements, the exhaust
travels through an exit passage 810 and an exit valve 812.
[0071] The opening of the valve 808 is controlled by a signal from
a heat sealing element controller that receives a temperature
sensor input. The valve 808 is opened by the controller in response
to a predetermined temperature of the heat sealing elements being
exceeded. For example, if the heat-sealing layer of the vacuum
packaging bag melts at 130 degrees, the predetermined temperature
may be set at 120 degrees. This ensures that the heat sealing
elements 420 stay below a melting temperature, so as to not
prematurely produce a heat seal while the vacuum packaging bag is
being evacuated. The controller may also open and close the valve
808 as necessary, in order to keep the heat sealing elements at a
constant predetermined temperature or within some range below the
predetermined temperature. A flowchart of the steps in this process
is shown in FIG. 19.
[0072] FIG. 8A shows an embodiment of the present invention wherein
the vacuum packaging appliance has two heat sealing elements. FIG.
8A shows a view looking at the base of the appliance 100 from
above, as a vacuum bag 804 is placed in to the appliance and into
the trough 430. In this embodiment the heat sealing elements are
comprised of two separate wires, 441 and 442. Each wire when
actuated with a current signal from a controller, becomes hot
enough to melt the sealing layer of the vacuum packaging receptacle
804. As will be described below with reference to FIGS. 9 and
13-18, these two heat sealing wires 441 and 442 are individually
controlled to allow for precise temperature control based on a
number of predetermined settings and/or predetermined conditions.
For example, heavy seals are created by energizing both wires,
while lighter seals are produced energizing only one of the two
wires 441 or 442, wherein the heavy and light seals may be desired
for a variety of reasons as described below.
[0073] A schematic diagram of the control circuitry of the heat
sealing element of the above embodiments of the appliance 100 and
150 is shown in FIG. 9. Included is the temperature sensor 90 that
feeds a real-time temperature signal TC1 of the heating elements
back to the controller 92. Also included is a temperature sensor 93
that feeds a real-time temperature signal TC2 of the base 104 (FIG.
1) or 155 (FIG. 1A) in the proximity of the heating element 420
back to a controller 92. The controller 92 is an application
specific integrated circuit or (ASIC) device. The controller 92 may
also be a programmable logic device (PLD) or any other type of
microprocessing device capable of being programmed to control the
functions of the vacuum packaging appliance as described
herein.
[0074] As mentioned above, problems with overheating and faulty
sealing result from inaccurate temperature control of the heat
sealing elements 420. The sensor 90 allows the controller 92 to
supply more or less electrical power to the elements based on this
temperature.
[0075] For example, in the vacuum sealing appliance 100 a standard
heavy seal would be to supply current to the elements for a
predetermined period of 5 seconds creating an optimal predetermined
vacuum bag temperature of 130 degrees (54.degree. C.) (required to
melt the interior heat sealing layer). If the present heat sealing
element temperature is already 110 degrees (43.degree. C.), a heavy
seal may be produced by only supplying current for a duration of 2
seconds. The total time T the indicator light 314 (FIG. 3) would
flash intermittently green to indicate sealing would be for 5
seconds taking into account the amount of time T1 of 2 seconds the
current was on and a delay time D of 3 seconds. This process or
algorithm thereby increases the power efficiency of the appliance
and does not damage the heat sealing elements 420 by overheating
them with a full 5 second duration heavy seal pulse.
[0076] Thus, as the sensor 90 senses that the heat sealing elements
420 are getting too hot, the actual sealing time T1 (time the
current to the heating elements 420 is on) is shortened and the
dwell time D is increased. If the sensor 90 senses that the heating
elements 420 are cooler, then the actual sealing time T1 is
increased and the dwell time D is shortened. In the alternate
embodiment vacuum sealing appliance 150 it has been found that
varying the actual sealing time T1 and dwell time D in this manner
significantly increases the number of repetitive sealing cycles
(greater than 25) that may be performed without the vacuum
packaging appliance 150 overheating. A sealing operation cycle
begins when the single seal button 370 is depressed. A vacuum and
sealing operation begins when the vacuum and seal button 372 is
depressed. The vacuum portion of the sealing operation cycle is
described above in the embodiment of the vacuum and sealing
appliance 100 and is substantially identical in operation in the
alternate embodiment appliance 150.
[0077] As the vacuum and sealing operation cycle continues progress
indicator lights 381-385 are energized indicating various stages of
progress of the vacuum portion of the vacuum and sealing operation
cycle. For example, in the illustrated embodiment there are five
progress indicator lights 381-385 which are lighted in succession
during five corresponding portions of the vacuum portion of the
vacuum and sealing operation cycle described below. The progress
indicator light 381 is lighted during the first twenty percent
portion of the vacuum operation cycle, the progress indicator light
382 is lighted during the second twenty percent portion, etc.
[0078] There could be many possible numbers and/or configurations
of progress indicator lights and portions of the vacuum operations
of the vacuum and sealing operation cycle are divided into so the
above example is not meant to be limiting. The plurality of
progress indicator lights 381-385 emit a solid green light when
energized but could emit any other color light including red or
amber.
[0079] The sealing portion of the both the sealing operation cycle
and the vacuum and sealing operation cycle includes both the time
T1 the current was being supplied to the heater elements 420 and
the dwell time D after the current was shut off. Seal indicator
light 386 is also energized and lighted when the sealing operation
is being performed and is not extinguished until the sealing
operations are completed. The seal indicator light 386 emits a red
color light when energized but could emit any other color including
green or amber.
[0080] Examples of seal timings or the total time T for sealing
(current on time T1+dwell time D) that have been found to be
advantageous for the vacuum sealing appliance 150 according to the
real-time heat sealing element temperature TC 1 of the heat sealing
elements 420 for both AC power and DC power sources may be stored
in look-up tables such as Tables A and B below:
TABLE-US-00001 TABLE A AC Power Source TC1 .ltoreq. 40.degree. C.,
TI = 9 seconds, D = 3 seconds 40.degree. C. < TC1 .ltoreq.
45.degree. C., TI = 8 seconds, D = 4 seconds 45.degree. C. < TC1
.ltoreq. 50.degree. C., TI = 7 seconds, D = 5 seconds 50.degree. C.
< TC1 .ltoreq. 55.degree. C., TI = 6 seconds, D = 6 seconds TC1
> 55.degree. C., TI = 5 seconds, D = 7 seconds
TABLE-US-00002 TABLE B DC Power Source TC1 .ltoreq. 30.degree. C.,
TI = 20 seconds, D = 3 seconds 30.degree. C. < TC1 .ltoreq.
45.degree. C., TI = 18 seconds, D = 5 seconds 45.degree. C. <
TC1 .ltoreq. 50.degree. C., TI = 8 seconds, D = 7 seconds TC1 >
50.degree. C., TI = 5 seconds, D = 7 seconds.
[0081] Note that the time T1 the current being supplied to the
heater elements 420 is longer in Table B for a DC power source
since the amplitude of the current from a DC power source is
typically less than that which can be provided by an AC power
source. Alternately, the above values may be computed using an
algorithm known to one of ordinary skill in the art in order to
energize the heating elements 420 to an optimum pre-determined
sealing temperature.
[0082] The controller 92 may prevent the above vacuum and sealing
operations in the vacuum sealing appliance 150 if the sensor 93
detects that the temperature TC2 of the base 155 exceeds 65.degree.
C. or the temperature TC1 exceeds 75.degree. C. If either of these
conditions is met, the controller 92 will flash the seal indicator
light 386 red and disable all operational controls including the
single seal button 370 and the seal and vacuum button 372 until the
temperature TC2 is below 65.degree. C. and the temperature TC1 is
below 75.degree. C.
[0083] In addition to changing the pulse duration, the controller
may also change the amplitude of the pulse or change both amplitude
and duration if desired. When controlling actuation pulses to the
two elements as shown in FIG. 8A, the controller 92 may actuate
only one of the wires 441 or 442 based on temperature conditions as
described above. For example, if the elements are already warm,
only one element 441 is energized. If the elements are cool, both
wires 441 and 442 are actuated by the controller 92.
[0084] The liquid sensor 91 feeds a signal back to the controller
92 indicating the presence or amount of liquid in the trough 430.
This is important as the presence of liquids may require higher
sealing temperatures of the elements 420, as liquids tend to reduce
the effects of the heat sealing elements. Therefore the controller
92 would produce a heat seal activation signal of greater duration
when liquids are present, or send sealing actuation pulses to both
sealing elements 441 and 442 as shown in FIG. 8A. FIG. 15 shows
this process in detail. Regarding the details of the liquid sensor,
patent application with Ser. No. 60/492,046, entitled "Fluid
Sensing in a Drip Tray", by inventors Charles Wade Albritton,
Landon Higer and John Peters, which is hereby incorporated by
reference.
[0085] FIG. 10 shows a method of controlling the vacuum packaging
device. In step S10 the process is begun when the operator seals a
first end of the container bags. It may be desired to seal a first
and second end of the vacuum bags in the exact same manner by the
operator.
[0086] Sealing both ends of the bag in the same manner ensures an
ease of operation that results in less operator errors and thereby
decreases the wasted bag material. After a first end of the bag has
been sealed the operator places items to be packaged into the bag.
The bag that is ready for sealing is then placed into the device
for evacuating and heat sealing the second end of the container in
step S20. In step S30 the operator selects the appropriate type of
seal. In step S40 the heat sealing element may be moved into
position by closing the lid of the device itself. In step S50 the
heat sealing controller instigates the chosen type of seal by
controlling the current to the sealing element or elements. As
described above, the heat sealing process is controlled by the
controller 92 in accordance with the inputs from multiple sensors
and internal logic and programming. The process is then finished in
step S60.
[0087] The sealed bag of the present invention is shown in FIG. 11.
The vacuum sealed container 10 has heat seals 11 and 12 after being
processed by the vacuum packaging appliance.
[0088] The length of bag material between the ends and the heat
seals 11 and 12 is minimized. By incorporating the heat sealing
element adjacent to the trough, the seal may be placed closer to
the container end, thereby resulting in less bag waste. This is a
substantial improvement over prior art bags as shown in FIG. 12.
FIG. 12 shows heat seals 21 and 22 that are far from the bag ends
resulting in substantial waste and cost to the user.
[0089] FIG. 13 shows a method 1300 of controlling the vacuum
packaging device. In step S1302 the process begins when the
operator couples the storage receptacle to the vacuum circuit by
placing the container into the vacuum packaging appliance. In step
S1304, the vacuum circuit is closed when the operator closes the
lid of the device. In step S1306 the type of heat seal is
determined. As is described below and as shown in FIGS. 14-18, this
step may contain inputs from a variety of parameters in order to
determine the exact nature of the control signal applied to the
heat sealing elements. In step S1308 the container is evacuated and
is ready for sealing. In step S1310 the heat sealing element is
actuated according to the determined control signal. This step may
include determining if one or both wires 441 and 442 (as shown in
FIG. 8A) are to be actuated. In step S1312 feedback of the heat
sealing process is provided to the user. For example lights on the
control panel may indicate that sealing is being performed and/or
that the heat sealing process is complete. As shown in FIG. 9, the
heat sealing controller determines and actuates the current
provided to the heat sealing element. As described above, the heat
scaling process is controlled by the controller 92 in accordance
with the inputs from multiple sensors and internal logic and
programming.
[0090] FIG. 14 shows in more detail how the control signal is
determined in step S1310 above. The process begins in step S1402 by
receiving the user input regarding the type of heat seal selected.
This input comes from the control panel shown in FIG. 3 and
described above.
[0091] In step S1404 the proper control signal is determined by the
controller 92. In this manner the time of the control signal to the
heat sealing elements is input. As will be described below, the
control signal set by the operator may change in accordance with
the amount of liquid sensed in the trough and/or the temperature of
the heating elements.
[0092] FIG. 15 shows in more detail how the control sigral may be
adjusted in step S1310 above. The process begins in step S1502 by
monitoring the presence and amount of liquid in the trough during
the evacuation process in step S1308. The liquid sensing electrodes
as shown in FIG. 7 provide this information to the controller
circuit 92. In step S1504 it is determined by the controller if a
predetermined threshold of liquid has been exceeded. If the liquid
is below a certain level, step S1508 is enacted and the time of the
control signal to the heat sealing elements is set to a normal
period (as set by the operator). If it has been determined in step
S1504 that a predetermined amount of liquid is present, step S1506
adjusts the set time of the control signal to the elements to be
high or energizes both heat sealing wires 441 and 442 as shown in
FIG. 8A. By incorporating the liquid sensing electrodes into the
trough of the appliance, the heat seal may be controlled in a more
precise manner, thereby resulting in less bag waste. This is a
substantial improvement over prior art devices that are incapable
of monitoring and adjusting the heat sealing process in accordance
with the amount of liquid detected during the evacuation
process.
[0093] FIG. 16 also shows in detail how the control signal is
determined in step S1310 above. The process begins in step S1602 by
monitoring the present temperature of the heat sealing elements.
The temperature sensor as shown in FIG. 7 provides this information
to the controller circuit 92. In step S1604 the controller
determines if a predetermined threshold of temperature has been
exceeded. If the temperature is below a certain level, step S1608
is enacted and the vacuum packaging appliance continues with the
evacuating and heat sealing operations in a normal manner. If it
has been determined in step S1604 that a predetermined temperature
has been exceeded, step S1606 waits or suspends operations for a
predetermined period of time until the heat sealing elements have
cooled.
[0094] By incorporating the temperature sensor adjacent to the
trough of the appliance, the heat seal may be controlled in a more
precise manner, thereby resulting in less bag waste. This is a
substantial improvement over prior art devices that are incapable
of monitoring and adjusting the heat scaling process in accordance
with a plurality of sensor inputs and control modes.
[0095] In addition to suspending the heat sealing operations as
described above, the present invention is also capable of adjusting
the control signal times based on the temperature of the elements.
FIG. 17 shows a flowchart of steps 1700 enacted by the controller
92. The controller 92 stores control signal times for all the heat
seal settings from which the operator may select.
[0096] A light or heavy seal control signal time duration may also
be increased or decreased based on the real-time feedback of the
temperature of the heat sealing elements. The controller 92 may
therefore be programmed to keep the heat sealing elements at a
constant temperature while sealing or within a predetermined
temperature range while sealing.
[0097] The process begins in step S1702 when the temperature of the
heat sealing elements is detected and sent to the controller. In
step S1704 the controller adjusts the duration of the control
signal applied to the heat sealing elements based on their
real-time detected temperature. As per the algorithm mentioned
above, more or less current may be applied to the elements based on
their sensed temperature. For example a warm heating element may
require 3 seconds of current to produce a seal, whereas a cold heat
sealing element may require 5 seconds of current to produce a
similar heat seal. In addition to varying the activation signal
duration, other embodiments may adjust the amplitude and/or
duration of the control signal in a real-time manner as applied to
each individual sealing wire 441 and 442 as shown in FIG. 8A. Step
S1704 may also include waiting for the heat sealing elements to
cool down.
[0098] The algorithm enacted by controller 92 can also adjust
waiting times for cooling periods. For example a wait time of 20
seconds may be required for a hot element at 150 degrees to cool
down to 100 degrees, and a wait time of 10 seconds may be required
for an element at 135 degrees to cool to 100 degrees. It is also
contemplated that the algorithm can maintain the element
temperature at some constant temperature during the sealing
process.
[0099] FIG. 18 shows another method of the present invention. In
this method the controller 92 adjusts the control signal provided
to the elements based on inputs from the control panel, the
temperature of the heat sealing elements, and the amount of liquid
sensed in the trough. The process begins in step S1802 by receiving
the user selected type of heat seal. In step S1804 the controller
receives information regarding the temperature of the heat sealing
elements from the temperature sensor 90. In step S1806 the
controller receives information regarding the amount of liquid in
the trough from the liquid sensor 91. In step S1808 the controller
takes into account all the information described above and adjusts
the control signal based on the selected seal setting, the
temperature of the elements and the amount of liquid in the trough.
The appropriate control signal is then sent from the controller to
actuate the sealing elements in step S1810.
[0100] For example, the operator may select a medium heat seal
which would have a control signal duration of 4 seconds. If the
temperature of the heat sealing elements was detected to be 110
degrees, 0.5 seconds of time duration may be subtracted from the
control signal, as the heat sealing elements are already warm. If a
substantial amount of liquid is detected by the liquid sensors, the
controller may add 1.0 second of time to the duration of the
control signal. This results in an appropriate control signal
duration of 4.5 seconds to be applied to the heat sealing elements.
The controller 92 may use an algorithm or look-up table such as
Tables A and B to determine these adjusted control signal periods
based on these pertinent parameters.
[0101] In another embodiment, the process as shown in FIG. 18 is
also applied to the heat sealing wires as shown in FIG. 8A. In this
environment, the controller 92 adjusts the control signal (in an
on/off manner) provided to the plurality of elements based on
inputs from the control panel, the temperature of the heat sealing
elements, and the amount of liquid sensed in the trough. For
example, when the elements are detected to be hot (a predetermined
temperature has been exceeded) as sensed by the temperature sensor,
only one of the two wires may be energized. When liquids are
detected, both wires 441 and 442 are activated to ensure that the
presence of liquid does not effect the heat seal. The operator may
also select a "light" or "heavy" seal by using the control panel
switches. In this instance a "light" seal would activate only one
wire, while a "heavy" seal would activate both wires.
[0102] FIG. 19 shows a flowchart of steps in another embodiment of
the present invention. The process begins in step S1902 by
monitoring the present temperature of the heat sealing elements as
the vacuum packaging appliance is evacuating a receptacle. The
temperature sensor as shown in FIG. 7 provides this information to
the controller circuit 92. In step S1904 the controller determines
if a predetermined threshold of temperature has been exceeded. If
the temperature is below a certain level, step S1908 is enacted and
the vacuum packaging appliance continues with the evacuating and
heat sealing operations in a normal manner.
[0103] If it has been determined in step S1904 that a predetermined
temperature has been exceeded, step S1906 is enacted wherein the
controller produces a signal that opens a valve which enables the
vacuum pump exhaust to be blown under the heat sealing elements in
order to cool the elements. This process provides real-time
feedback and control of the heat sealing elements temperature. This
process reduces the amount of faulty seals that occur when the
elements are warm from previous use and begin to prematurely melt
the heat sealing layer within the vacuum packaging bags before they
are completely evacuated. This process also ensures that the heat
sealing elements maintain an acceptable temperature range so that
they may be subsequently controlled by the controller using the
methods described above.
[0104] FIG. 20 illustrates a preheat method according to another
embodiment of the present invention. This method is well suited to
particularly thick vacuum packaging receptacles and vacuum
packaging receptacles that have large ridges or patterns thereon. A
step S100 begins by energizing a sealing mechanism to a preheat
level. The preheat step S100 is typically done in conjunction with
an evacuation step, rendering the receptacle ready for easy and
prompt sealing. The preheat step S100 could raise the sealing
mechanism temperature to any suitable level, for example somewhat
lower than the actual sealing temperature. This prepares the
receptacle for actual sealing, but does not initiate substantial
sealing that tends to interfere with evacuation. A step S102
completes the sealing process by fully energizing the heat sealing
mechanism.
[0105] FIG. 21 shows in more detail how the control signal may be
adjusted in step S1310 above in the sealing operations of the
vacuum sealing appliance 150. In step S2102, it is determined
whether the temperature TC2 of the base 155 as measured by sensor
93 is less than 65.degree. C. or if the temperature TC1 of the
heating elements 420 is less than 75.degree. C. If both of these
conditions are not satisfied, in step S2104 the controller 92
flashes the seal indicator light 386 red and disables all
operational controls including the single seal button 370 and the
seal and vacuum button 372 until these conditions are met. If both
of these conditions are met, then in step S2106 the controller 92
may energize the heating elements 420 and the seal indicator light
386.
[0106] In step S2108, the container 20 is sealed by energizing the
heater elements 420 for a length of time T1 according to the
real-time temperature TC1 of the heater elements 420. For example,
if the real-time temperature TC1 of the heat sealing elements 420
was detected to be less than or equal to 40.degree. C. (104.degree.
F.), the heater elements 420 would be energized for a time T1 of 9
seconds. The time T1 that the heater elements 420 is energized for
a given real-time temperature TC1 may be derived from an algorithm
or stored as values retrieved from a look-up table such as tables A
and B above.
[0107] After the time T1 of 9 seconds has elapsed, in step S2110
the controller 92 de-energizes the heater elements 420 and
initiates a dwell time D of 3 seconds that corresponds to the time
T1. The dwell time D may be derived from an algorithm or may be
values retrieved in look-up tables such as Tables A and B above
along with the corresponding heater elements 420 temperature
TC1.
[0108] After the dwell time D has passed, in step S2112 the
controller 92 extinguishes the seal indicator light 386. Another
vacuum and sealing operation cycle or sealing operation cycle, if
desired, may then be initiated. Without the dwell time D after the
sealing operation, the heater elements 420 may be too hot to allow
another container 20 to be inserted into the appliance 150 in a
subsequent sealing operation cycle. The dwell time D ensures the
heater elements 420 have cooled sufficiently to allow another
container 20 to be inserted in to the appliance 150.
[0109] The appliances described above show the heat sealing
mechanism external to the vacuum chamber. However, the teaching of
the present invention works equally well with appliances having the
heat sealing mechanism internal to the vacuum chamber. One suitable
example of this is commonly assigned U.S. provisional patent
application 60/492,090, filed Jul. 31, 2003, and incorporated
herein by reference. Additionally, the appliances described
illustrate the receptacle external to the vacuum chamber. As will
be appreciated, the teachings of the present invention work well
with in-chamber vacuum packaging appliances.
[0110] The vacuum packaging device described herein therefore
provides numerous embodiments and methods to cool the heat sealing
elements and embodiments and methods to control and energize the
heat sealing elements that may be used in combination or separately
as desired. It will be understood by those skilled in the art that
the above-presented description is provided by way of example only
and is not intended to be limiting in anyway. Those skilled in the
art will readily understand that numerous other embodiments of the
invention are contemplated and possible which meet the scope and
spirit of the invention.
[0111] All references cited herein are expressly incorporated by
reference in their entirety.
[0112] It will be appreciated by persons skilled in the art that
the present invention is not limited to what has been particularly
shown and described herein above. In addition, unless mention was
made above to the contrary, it should be noted that all of the
accompanying drawings are not to scale. A variety of modifications
and variations are possible in light of the above teachings without
departing from the scope and spirit of the invention, which is
limited only by the following claims.
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