U.S. patent application number 09/977999 was filed with the patent office on 2002-04-18 for controlled gas packaging.
Invention is credited to Costello, Anthony William, Hoddinott, Charles Geoffrey.
Application Number | 20020043050 09/977999 |
Document ID | / |
Family ID | 19928189 |
Filed Date | 2002-04-18 |
United States Patent
Application |
20020043050 |
Kind Code |
A1 |
Costello, Anthony William ;
et al. |
April 18, 2002 |
Controlled gas packaging
Abstract
A method and apparatus for controlled or modified atmosphere
packaging of products such as foodstuffs, whereby the product (17)
is weighed prior to or in the packaging machine and regulating the
amount of gas inserted into the package in proportion to the weight
of the product. User controlled variables may be used to determine
the amount of gas to be injected into a package for a given weight
or size of package, typically 1.5 to 1.75 liters of Carbon Dioxide
per Kg of meat cut depending upon the type of meat, number/size of
voids and bag size.
Inventors: |
Costello, Anthony William;
(Tauranga, NZ) ; Hoddinott, Charles Geoffrey;
(Auckland, NZ) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET 2ND FLOOR
ARLINGTON
VA
22202
|
Family ID: |
19928189 |
Appl. No.: |
09/977999 |
Filed: |
October 17, 2001 |
Current U.S.
Class: |
53/434 ;
53/512 |
Current CPC
Class: |
B65B 31/06 20130101;
B65B 31/024 20130101; B65B 31/048 20130101; B65B 51/146
20130101 |
Class at
Publication: |
53/434 ;
53/512 |
International
Class: |
B65B 031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 17, 2000 |
NZ |
507613 |
Claims
We claim:
1. Apparatus for controlled or modified atmosphere packaging of
products, including means for weighing a product to be packaged;
means for insertion of a product into a package; means for
evacuating the package; means for injecting a gas into the package;
means for regulating the amount of gas injected based on
information on the weight of product from the weighing means and
means for sending the package.
2. Apparatus as claimed in claim 1, wherein the weighing means
provides an output to a control device such as microprocessor which
in turn can be used to control the amount of gas injected into the
package.
3. Apparatus as claimed in claim 1, wherein the weighing means
forms part of the packaging machine.
4. Apparatus as claimed in claim 1, wherein the weighing means is a
weigh station situated prior to the packaging machine.
5. Apparatus as claimed in claim 1, wherein the weighing means is
closely associated with the apparatus.
6. Apparatus as claimed in claim 1, wherein the weighing means is
associated with a conveyor conveying product to the packaging
machine so that the weight of the product is determined before the
product reaches the packaging machine.
7. Apparatus as claimed in claim 1, wherein the packaging machine
has a manual control to enable the user to set the amount of gas
per weight or type of product.
8. A method of controlling the amount of gas injected into a
package by determining the weight or type of product, and
automatically varying the amount of gas injected based on the
weight of the product.
9. A method as claimed in claim 8, wherein the method involves
setting a user determined variable to regulate the desired amount
of gas per weight of product, and combining this setting with the
weight of the product.
Description
FIELD OF INVENTION
[0001] This invention relates to method and apparatus for
packaging, and has particular application to the packaging of
spoilable materials, e.g. foodstuffs, and in particular meat cuts
in a controlled or modified atmosphere bag.
BACKGROUND
[0002] Previous methods of packaging spoilable material have
involved packing the product within a plastic bag or the like,
evacuating the bag, then injecting a standard amount of gas or gas
mixture in place of the air. This is sometimes called "controlled
atmosphere packaging" or "modified atmosphere packaging". One
example of such machines is our Captech machine described in U.S.
Pat. No. 4,926,614. Prior art machines required operators to
inspect the product prior to gas injection. In some cases a small
pack could be overfilled with injected gas leading to ballooning or
bursting of the bag. In other cases the bag would be underfilled,
resulting in crushing of the pack when the gas was absorbed by the
meat.
OBJECT
[0003] It is an object of this invention to provide an improved
packaging method and/or apparatus, or one, which will at least
provide the food industry with a useful choice.
STATEMENT OF INVENTION
[0004] In one aspect the invention provides a method of controlling
the amount of gas injected into a package by determining the weight
of the product, and automatically varying the amount of gas
injected in proportion to the weight of the product.
[0005] Preferably the method involves setting a user determined
variable to regulate the desired amount of gas per weight or type
of product, and combining this setting with the weight of the
product, which preferably is automatically weighed in the packaging
machine or prior to the product reaching the packaging machine.
[0006] In another aspect the invention provides apparatus for
controlled or modified atmosphere packaging of products, including:
means for weighing a product to be packaged; means for insertion of
a product into a package; means for evacuating the package; means
for injecting a gas into the package; means for regulating the
amount of gas injected based on information on the weight of
product from the weighing means and means for sending the
package.
[0007] Preferably the weighing means provides an output to a
control device such as microprocessor which in turn can be used to
control the amount of gas injected into the package.
[0008] Preferably the weighing means is closely associated with the
apparatus. In one version of the invention, the weighing means can
form part of the packaging machine, and in another aspect, the
weighing means can be a weigh station situated prior to the
packaging machine, more preferably its forms part of a conveyor
conveying product to the packaging machine so that the weight of
the product is determined before the product reaches the packaging
machine.
[0009] Preferably the packaging machine has provision to enable the
user to set the amount of gas per weight of product, as the user
may wish to vary the amount of gas per weight of product depending
upon type of product, its capability of absorbing the injected gas,
the number and type of voids associated with the product, the size
of the bag, or the physical size or shape of the product.
[0010] By way of example, the packaging of meat there is an
industry "rule of thumb" that lamb or beef cuts will absorb about
one liter of carbon dioxide per kilogram of meat. Based on this
figure, some Meat Processors prefer to inject about 1.5 liters of
carbon dioxide per kilogram of meat, while some may prefer to set
their machine to attempt to insert 1.75 liters of carbon dioxide
per kilogram of meat. It is difficult to ensure the meat cuts are
precisely the same weight, and for example a meat pack intended to
contain 10 kg of meat on average, may contain anywhere between 8
kg-11.5 kg of meat.
DRAWINGS
[0011] These and other aspects, which should be considered in all
its novel aspects will become apparent from the following
description, which is given by way of example only, with reference
to the accompanying drawings, in which:
[0012] FIG. 1 illustrates a schematic view of a preferred packaging
apparatus.
[0013] FIG. 2 illustrates a top plan view of conveyor and gas
filling machine.
[0014] FIG. 3 illustrates a front elevation of the conveyor and
gas-filling machine of FIG. 2.
[0015] In example 1 the weighing means can be part of the chamber,
but in the case of example 2 the weighing means can be situated
prior to the chamber.
EXAMPLE 1
Weighing Means
[0016] In this example weighing of the product to be packaged can
take place as the product enters the chamber--preferably before
evacuation takes place. A weigh scale 12A can be situated on or
form part of the base 12 of the chamber. Information on the weight
of the product can then be used to automatically adjust the amount
of gas to be injected into the package--see below.
[0017] By way of example we use a chamber 10 defined by a removable
cover 11 and a base 12, although any other type of gas flushing
apparatus can be used with this inventive concept.
[0018] Gas passages are provided, connecting the apparatus to a
vacuum source 23 and one or more gas sources 24. One passage 25
includes a snorkel 13 intended for connection with a container held
in the chamber 10, as detailed below, and a second passage 14
provides access to the chamber 10 itself. In some applications, it
may be desirable to provide pairs of passageways, one connected to
the vacuum source and one to a gas source. Alternatively, as shown
single passageways may be used with appropriate valves to switch
the passageway between the two functions.
[0019] Preferably the chamber 10 is of a size able to comfortably
accommodate a box 15 and heat sealable bag 16 with its contents
17.
[0020] In its preferred form the apparatus includes clamping and
sealing apparatus for the bag 16, inside the chamber 10, separate
and independently movable from the cover 11. This apparatus
includes clamping bars 18 mounted around the snorkel 13 for
temporarily clamping the mouth of the bag around the snorkel 13,
and sealing bars 19 positioned beyond the snorkel 13 for sealing
the mouth of bag 16 between the snorkel and the product 17.
[0021] One or both sealing bars 19 are movable, preferably by the
use of a pneumatic cylinder 20, such that the mouth of the bag can
be left open or sealed shut between the snorkel 13 and the product
17. The upper clamping bar 18 and sealing bar 19 can be mounted on
a pivotable jaw 21 with a handle 22 by which it may be moved up or
down. All this apparatus is contained in the chamber 10 along with
the product 17 and its packaging, and is covered by the lid 11. An
airtight seal is formed between the lid 11 and the base 12 in
normal use.
[0022] It is preferable for the clamping bars 18 to be positioned
behind the sealing bars 19 as shown, rather than in front of them.
If the clamping bars 18 were positioned in front of the sealing
bars 19 with the snorkel 13 protruding through them, it would be
necessary to withdraw the snorkel before sealing the bag, and
furthermore a small pocket of air would inevitably be trapped
between the clamping bars and the seal, and would be released into
the bag upon removal of the clamping bars. With the arrangement of
the present invention the snorkel is not required to move, and
there is no air entrapment at the mouth of the bag.
[0023] In use, the product 17 to be packed is placed within a heat
sealable bag 16 and box 15, and is then placed within the chamber
10. The chamber has appropriate seals about its edge, so that the
chamber itself can be evacuated as well as the bag. The bag is
placed within the chamber 10 and the mouth of the bag 16 fitted
over the snorkel 13. The bag is then clamped off across the snorkel
with the pair of clamp bars 18.
Evacuation
[0024] The chamber 10 and the bag 16 are evacuated, preferably
simultaneously, so that the bag is completely emptied. By
controlling the pressure within the chamber as the bag is
evacuated, the bag can be controlled so that it does not collapse
too soon, cutting off communication between contents and the
snorkel 13. Preferably both the chamber and the bag are evacuated
from the same source, but the snorkel 13 is narrower than the
passageway 14. This means that the chamber is evacuated faster than
the bag, and the bag expands inside the chamber as it is emptied,
rather than collapsing. This prevents air being trapped in pockets
in the bag. Alternatively, the bag and the chamber could be
evacuated at the same rate. Even if the bag empties slightly faster
than the chamber and collapses as a result, the difference between
the air pressure in the bag and the air pressure around it will not
be great enough to trap air inside.
[0025] When a desired vacuum level in the chamber is achieved, a
vacuum pressure switch 26 stops the evacuation and holds the
chamber at that vacuum level. The evacuation of the bag continues
through the nozzle 13, and the bag collapses as a result. When the
desired vacuum level in the bag is reached a second pressure switch
27 is activated. The chamber and the bag are then refilled. The use
of pressure switches to turn the system on and off allows the
vacuum level to be accurately determined and achieved without undue
stress being put on the bag in the process. By using the same
vacuum source to evacuate both chamber and bag it is easy to avoid
having any great difference between the pressures in each.
[0026] To speed up the last stages of evacuation of the bag, it may
be found desirable to refill the chamber slightly after activation
of the first pressure switch and initial collapse of the bag, to
put greater pressure on the bag and squeeze the last of the air
out. Such collapsing of the bag could result in entrapment of air,
but because the bag is already substantially evacuated at this
stage this will in general not be a problem.
[0027] This system also allows visual checking, in that the bag can
be seen to inflate and collapse within the chamber (given one or
more windows in the chamber lid or walls) at different times in the
process. If, for example, the proper vacuum is not achieved in the
bag for any reason, it will not collapse even if a partial
reduction of pressure has occurred, because the internal pressure
will still be greater than that in the chamber.
Gas Filling
[0028] When the bag is fully empty, or as empty as the vacuum pump
can make it within the desired cycle time, the chamber and the bag
are refilled, preferably at the same rate. This time the bag is
filled with a selected gas or gas mixture introduced through the
nozzle 13. In the case of packaging meat the gas is commonly carbon
dioxide, although other gases or gas mixtures may be used.
Depending upon the nature of the contents of the bag other gas
mixtures may be used to control the storage, ripening, or other
qualities of the item stored within the bag.
[0029] While the bag is being filled with a gas or gas mixture, the
chamber is also filled, most conveniently with air, although other
gases could be used. By filling the chamber at a controlled rate at
the same time as filling the bag, it is possible to balance the
pressure between the gas within the bag, and the air within the
chamber. This allows the bag to be filled accurately with a metered
quantity of gas, and also avoids undue pressure being placed on the
bag.
[0030] The amount of gas injected into the bag can be controlled by
the microprocessor, which determines the amount of gas based on the
user settings and the weight of the product. For example, one meat
processor may wish to achieve set rates of 1.5 liters of Carbon
Dioxide per Kg of meat cuts, whilst another may prefer to achieve
fill volumes of 1.7 liters of Carbon Dioxide per Kg of meat cuts.
By entering the required settings the machine can calculate the
required amount of gas based on the weight of the product. This has
not been possible in prior art equipment where the average pack
size may be for example 10 kg but packs may range in size from 8 kg
to 11.5 kg for example.
[0031] When atmospheric pressure has been reached in the chamber,
the cover 11 of the chamber can be removed, and the sealing bars 19
brought together to seal the bag 16. If two chambers are used
together, the cover 11 can be shifted to the second chamber at this
stage, and evacuation of another bag commenced while the first is
being sealed. When the bag is sealed, the clamping bars 18 can be
released and the bag removed from the chamber.
[0032] This example has the advantage that the bag can be well
evacuated to leave a very low amount of residual air, and then
accurately filled with a known quantity of gas, and avoids the
disadvantages of prior vacuum packaging methods in which the bag is
exposed to atmospheric pressure during the vacuum and gas flushing
operations. It also has the advantage that only the bag is filled
with the required amount of gas calculated on the weight of the
product and any user settings, and no gas is allowed to escape into
the chamber. It is also believed that the bags are less likely to
be damaged in the operation as there can be little or no stress on
the bag during filling.
EXAMPLE 2
[0033] In this example, any type of packaging machine can be used,
and for example it may be a packaging machine 10 of the type
illustrated and described with reference to FIG. 1, so that the
product can be inserted into a package, the package evacuated and
then gas filled to provide a controlled atmosphere prior to sealing
of the bag. (Except that the weigh station 12A is replaced by
external weigh station 54 situated prior to the product reaching
the packaging machine).
[0034] FIGS. 2 and 3 show the use of such as machine, in
association with an indexing in feed conveyor 50 and an output
conveyor 51.
[0035] Preferably the indexing in feed conveyor has an associated
weight station 54 situated beneath the conveyor belt so that the
product is weighed just before it enters the packaging machine.
[0036] Information on the way the product can be feed to the
microprocessor (not shown here but represented by numeral 30 in
FIG. 1) which in turn controls the evacuation of the bag and the
amount of gas injected, once the bag has been evacuated.
ADVANTAGES
[0037] By this means it is possible to more accurately determine
the amount of gas to be inserted into the bag, based on the weight
of the product.
[0038] This has the advantage that a production line can pack the
meat packs, and fill them with the required amount of gas more
accurately, and at a faster rate than conventional controlled
atmosphere packaging lines. Conventional lines require the operator
to visually inspect, and in some cases to manually adjust the
amount of gas per package based on the visual indication of the
size of the package. This slows down the process, and unless the
operator is extremely careful, will result in the ballooning or
bursting of some packages where excess gas is injected into a
smaller pack size, or too little gas is injected into a pack
resulting in the absorption of the gas into the meat during
transport, and subsequent crushing of the package. In neither case
the end result is acceptable.
[0039] Whilst it is possible to regulate the amount of gas
precisely based on the exact weight of the package, we prefer to
determine a number of weight bands for example, 8-8.5 kg, 8.5-9 kg,
9-9.5 kg, 9.5-10 kg, 10-10.5 kg, 10.5-11 kg, 11-11.5 kg and 11.5-12
kg and to determine if the weight of the package falls within one
of these bands, and then to inject a predetermined amount of gas
into the package in proportion to the amount specified for that
particular weight band. In addition the gas to be injected can be
varied depending upon the type of product, the transit time from
packing to retail display and purchased by the consumer. In some
cases we prefer to inject both carbon dioxide and nitrogen, so that
the amount of gas can be controlled carefully, allowing the carbon
dioxide to be absorbed by the meat during transport, whilst the
nitrogen remains as a buffer gas preventing crushing of the package
(which would be the case if only carbon dioxide was present and it
was fully absorbed by the meat).
[0040] By setting the parameter relating to the type of product to
be packed (for example ground beef which has a greater surface area
than a meat cut) and then using the automatic weighing, and
automatic regulation of the gas to be injected in proportion to the
information on a package weight, it is possible to greatly speed up
the controlled atmosphere packing of food products (and in
particular meat) whilst at the same time minimising the risk of
damage or spoilage to the product.
VARIATIONS
[0041] Whilst it is preferred the weighing of the product occurs in
the chamber as in example 1, or shortly prior to the chamber by
having a weigh station associated with the indexing and feed
conveyor 50, it is possible to weigh the combined package or their
contents separately, some distance from the machine, for example
when the meat cuts have been prepared, and then transmit this
information to the microprocessor. In either event the total
package weight (or the aggregate weight of the individual meat cuts
making up that package will be fed to the microprocessor so that
the required amount of gas can be injected automatically.
[0042] Finally, it will be appreciated that various alterations or
modifications maybe made to the foregoing without departing from
the scope of this invention.
* * * * *