U.S. patent application number 13/271747 was filed with the patent office on 2012-05-10 for method and chamber machine for sealing packaging material.
This patent application is currently assigned to MULTIVAC SEPP HAGGENMUELLER GMBH & CO. KG. Invention is credited to Dietmar Miller.
Application Number | 20120110956 13/271747 |
Document ID | / |
Family ID | 45047521 |
Filed Date | 2012-05-10 |
United States Patent
Application |
20120110956 |
Kind Code |
A1 |
Miller; Dietmar |
May 10, 2012 |
METHOD AND CHAMBER MACHINE FOR SEALING PACKAGING MATERIAL
Abstract
The disclosure relates to a method for sealing packaging
material and a chamber machine or a belted chamber machine for
implementation of the method for pre-heating at least one sealing
bar to a first temperature in order to facilitate the escape of
liquid, preferably
Inventors: |
Miller; Dietmar;
(Ungerhausen, DE) |
Assignee: |
MULTIVAC SEPP HAGGENMUELLER GMBH
& CO. KG
Wolfertschwenden
DE
|
Family ID: |
45047521 |
Appl. No.: |
13/271747 |
Filed: |
October 12, 2011 |
Current U.S.
Class: |
53/440 ; 53/127;
53/285; 53/477; 53/479 |
Current CPC
Class: |
B29C 66/1122 20130101;
B29C 66/71 20130101; B65B 51/32 20130101; B29C 66/0342 20130101;
B29C 66/0242 20130101; B65B 9/12 20130101; B29C 65/18 20130101;
B29C 66/723 20130101; B29C 66/919 20130101; B65B 31/024 20130101;
B29C 66/91951 20130101; B29C 66/944 20130101; B29C 66/92445
20130101; B29C 66/91445 20130101; B29K 2077/00 20130101; B29C
66/91421 20130101; B29C 66/7373 20130101; B29C 66/8322 20130101;
B29C 66/92921 20130101; B65B 51/146 20130101; B29C 66/3494
20130101; B29C 66/81422 20130101; B65B 55/24 20130101; B29C
66/81811 20130101; B29C 66/9672 20130101; B29C 66/849 20130101;
B29C 66/43121 20130101; B29C 66/71 20130101 |
Class at
Publication: |
53/440 ; 53/477;
53/479; 53/285; 53/127 |
International
Class: |
B65B 51/10 20060101
B65B051/10; B65B 63/08 20060101 B65B063/08; B65B 17/00 20060101
B65B017/00; B65B 31/04 20060101 B65B031/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 13, 2010 |
DE |
10 2010 048 401.6 |
Claims
1. A method for sealing packaging materials in a packaging machine,
the method comprising: heating a sealing bar before or during
establishing a contact with the packaging material to a first
temperature, which is lower than a sealing temperature and higher
than a temperature at which liquid product parts are at least
partially disintegrated to facilitate escape of the product parts
from a region in which the packaging material is sealed together
and maintaining the first temperature for a defined holding time;
and increasing the temperature of the sealing bar to the sealing
temperature and maintaining the sealing temperature until sealing
of the packaging material is concluded.
2. The method according to claim 1, wherein the first temperature
is at least 40.degree. C. and corresponds to the vaporization
temperature of water.
3. The method according to claim 1, wherein a first contact
pressure, which acts relatively between the sealing bar and a
counter-pressure strip or a further sealing bar when they are
pressed together, is lower than a sealing pressure during the
sealing process in a sealing time.
4. The method according to claim 1, wherein the packaging material
is a plastic film or a plastic laminated material and is preferably
a bag.
5. The method according to claim 1, wherein the packaging material
has a temperature resistance in a temperature range from
120.degree. C. to 250.degree. C.
6. The method according to claim 1, wherein the sealing temperature
is higher than 250.degree. C.
7. The method according to claim 3, wherein the sealing bar is
heated to a pre-heating temperature before being pressed against
the counter-pressure strip or a further sealing bar.
8. The method according to claim 1, wherein after sealing, the
sealing bar is actively brought to a cooling temperature.
9. The method according to claim 1, wherein an interchange of gas
follows an evacuation process.
10. A belted chamber machine for implementing the method of claim
3, wherein the belted chamber machine has a controller that is set
up to automatically control the temporal progression of the first
temperature and the sealing temperature of the sealing bar and the
contact pressure of the sealing bar against a counter-pressure
strip or against a further sealing bar as well as a holding time
for maintaining the first temperature and a sealing time.
11. The belted chamber machine according to claim 10, wherein the
controller is designed for the closed-loop or open-loop control of
the temperatures of at least two sealing bars enclosing the
packaging material.
12. The belted chamber machine according to claim 10, wherein the
controller comprises an input device on which an operating person
can specify the values, such as temperature, pressure and time,
needed for a sealing process.
13. The method of claim 5 wherein the packaging material comprises
a plastic bag.
14. A method for sealing packaging materials in a packaging
machine, the method comprising: providing a chamber machine having
a chamber and a movable belt that feeds into the chamber;
introducing a packaging material containing liquid product parts
into the chamber via movement of the belt; heating a sealing bar
before or during establishing a contact with an unsealed portion of
the packaging material to a first temperature, which is lower than
a sealing temperature and higher than a temperature at which the
liquid product parts are at least partially disintegrated to
facilitate escape of the liquid product parts from the unsealed
portion of the packaging material, and maintaining the first
temperature for a defined holding time; and increasing the
temperature of the sealing bar to the sealing temperature and
maintaining the sealing temperature until the unsealed portion of
the packaging material is sealed.
15. The method of claim 13, further comprising creating a vacuum
inside the chamber after the packaging material has been introduced
into the chamber.
16. The method of claim 15, wherein the first temperature is in a
range of 40.degree. C. to 220.degree. C.
17. The method of claim 16, wherein the packaging material
comprises a plastic bag and has a temperature resistance in a range
from 120.degree. C. to 25.degree. C.
18. The method according to claim 17, wherein the sealing
temperature is higher than 250.degree. C.
19. The method according to claim 18, wherein a first contact
pressure, which acts relatively between the sealing bar and a
counter-pressure strip or a further sealing bar when they are
pressed together, is lower than a sealing pressure during the
sealing process in a sealing time.
20. A belted chamber machine for sealing packaging material
containing product parts, the machine comprising: a chamber; a
movable belt capable of introducing packaging materials into the
chamber; a sealing bar located in the chamber, the sealing bar
capable of being heated before or during establishing a contact
with a packaging material to a first temperature, which is lower
than a sealing temperature and higher than a second temperature at
which the product parts are at least partially disintegrated to
facilitate escape of the product parts from a region in which the
packaging materials are sealed together; the first temperature of
the sealing bar capable of being maintained for a defined holding
time and also being capable of being increased to the sealing
temperature and maintained at the sealing temperature until sealing
of the packaging materials is concluded; and a controller
associated with the machine, the controller capable of
automatically controlling the temporal progression of the first
temperature and the sealing temperature of the sealing bar and the
contact pressure of the sealing bar against a counter-pressure
strip or against a further sealing bar as well as a holding time
for maintaining the first temperature and a sealing time.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims foreign priority benefits under 35
U.S.C. .sctn.119(a)-(d) to German patent application number DE
102010048401.6, filed Oct. 13, 2010 which is hereby incorporated by
reference in its entirety.
TECHNICAL FIELD
[0002] The disclosure relates to a method for sealing packaging
material, preferably a bag, and a chamber machine or belted chamber
machine for implementing the method.
BACKGROUND
[0003] From the state of the art, chamber machines and belted
chamber machines are known which seal plastic bags under vacuum
and/or modified atmosphere. Here, the operator can specify the
sealing time, sealing temperature and the time point as a function
of the set negative pressure in the chamber. The contact pressure
of the sealing bar onto a counter-pressure strip for the sealing
process is present here at an adequate level and is set by a
pressure reducer. Automatic means of control during the evacuation
and sealing process is not provided.
[0004] In DE 19815763 C2 a method is disclosed of improving the
detachment of the bag from the sealing bar after sealing in that
the sealing bar is heated at a second time point after sealing to a
second temperature which is above the sealing temperature.
[0005] In practice, with particular combinations of the material
property of the bag and the product and its intended use,
requirements arise which cannot be satisfied with the known
solutions in sufficient quality and an adequate level of process
safety is not provided.
[0006] For example, this occurs when packing products which have a
watery wetted surface, e.g. a whole chicken which has had an
aqueous marinade rubbed into it. Often the products are packed into
so-called "boil-proof" bags which in this case have a high
temperature resistance for temperatures of 200.degree. C. or
more.
[0007] Compared to the usual plastic bags, this leads to a very
narrow sealing temperature range of a few degrees Celsius in which
the bag can be sealed. In this respect, if the sealing temperature
is set slightly too high to increase the performance or to shorten
the sealing times or for the improvement of the sealing, then
irreparable melting of the film and an unsealed sealing weld is
produced and thus also a packed product which is unsatisfactory and
has to be eliminated.
[0008] A further problem is presented by deposits, such as for
example product parts of a marinade in the region of the sealing
weld, which are present on the inner sides of the bag due to the
product filling process. For example, this may be a herbal mixture
dissolved in water. Small constituent parts of the herbs, which are
located in the region where the sealing weld is to be produced, are
enclosed within the sealing weld by both sides of the film. Despite
this, they may permit a tight sealing weld and a reliably closed
bag. However, at the usual sealing temperatures the presence of
moisture or water particles leads to an increase in the volume of
the water particles and thus to inadequate sealing, because
firstly, the sealing weld is not closed off throughout or secondly,
weakening of the sealing weld occurs due to blister formation and
local leaks arise due to the inclusion of blisters.
SUMMARY
[0009] The object of the present disclosure is to make a method
available for sealing packaging material with which the
disadvantages described above can be remedied.
[0010] The following steps are provided in a method according to
the disclosure for the closure of packaging material in a packaging
machine.
[0011] At least one sealing bar is heated to a first temperature
before or while contact with the packaging material is established.
The first temperature is lower than a sealing temperature and
higher than a temperature at which liquid product parts are at
least partially disintegrated or dissolved to facilitate escape of
the product parts from a region in which the packaging materials
are to be sealed together. The first temperature is maintained over
a defined holding time.
[0012] The temperature of at least one sealing bar is increased to
a sealing temperature and held until sealing of the packaging
material is concluded.
[0013] The method is particularly advantageous for packaging in
which a product which, for example, has been externally treated
with an aqueous marinade, is enclosed by a packaging material,
preferably introduced into a bag, and the packaging material or the
sealable bag exhibits a particular suitability or a prescribed use
by an end user. For example, later the bag with the product can be
subjected to a higher temperature in an oven or in boiling water
and consequently the packaging material must have a very high
required temperature resistance of up to, for example, 250.degree.
C. Plastic bags of this nature are for reasons of cost preferably
made from a mono-material such as polyamide or nylon.
[0014] The method according to the disclosure is however also
suitable for all other currently available packaging materials in
permitting product parts to escape from the sealing region.
[0015] With aqueous product parts the first temperature preferably
corresponds to a temperature above 40.degree. C. and preferentially
the temperature corresponds to the vaporisation temperature of
water or it lies in a temperature range of 40.degree. C. to
220.degree. C.
[0016] A preferred embodiment of the method provides for a first
pressure, which acts relatively between the sealing bar and a
counter-pressure strip or another sealing bar, being lower than a
second pressure during the sealing process. In this way the
application of heat by the sealing bar into the packaging material
and the possibility of the escape of product parts from the sealing
region are optimised.
[0017] The packaging material can preferably be a plastic film or a
plastic laminated material preferably in the form of a bag.
[0018] Preferably, the packaging material can have a temperature
resistance, preferably for boiling or roasting the product,
preferably in a range from 120.degree. C. to 250.degree. C.
[0019] Preferably the sealing temperature is higher than
250.degree. C. so that the sealing weld remains closed during
boiling or roasting. To permit vapour to escape and for pressure
equalisation of an internal pressure which arises, normally small
holes are pierced in the packaging material or in the bag, for
example with a fork or knife, by the end user.
[0020] To shorten the process time for the packaging process,
preferably at least one sealing bar can be heated to a pre-heating
temperature before being pressed onto the counter-pressure strip or
onto the other sealing bar in order to shorten the warm-up time to
the first temperature.
[0021] The process time can preferably also or additionally be
brought to a cooling temperature by means of active cooling at
which the sealing bar is not immediately removed from the
counter-pressure strip or oppositely situated further sealing bar,
but instead after the sealing weld has solidified.
[0022] Before sealing, gassing may follow the evacuation process in
order to produce a modified atmosphere, or steam purging may occur
instead of evacuation.
[0023] A chamber machine or belted chamber machine according to the
disclosure for the implementation of the method according to the
disclosure comprises a controller which is set up for the
closed-loop or open loop control of the temporal progression of the
first temperature and the sealing temperature of at least one
sealing bar and the pressure of the sealing bar on the
counter-pressure strip or the further sealing bar as well as the
first time and the sealing time.
[0024] Preferably the controller regulates the temperatures of at
least two sealing bars, enclosing the packaging material in order
to ensure an optimised heat transfer from the sealing bars into the
packaging material and to optimise the complete packaging
process.
[0025] Preferably, the controller comprises an input device on
which an operator can specify the values, such as temperature,
pressure and their temporal progression for a process.
[0026] The method can also be used with packaging processes to heat
product parts such as sauces, meat juice and other liquids in the
sealing region before the sealing process such that they change
their state of aggregation and/or escape from the sealing region
due to the temperature change or they can be removed due to the
pressure on the film inner sides of the packaging material on the
product parts.
[0027] In the following, an advantageous embodiment of the
disclosure is presented in more detail with reference to the below
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 illustrates a schematic view of a belted chamber
machine;
[0029] FIG. 2a illustrates a schematic view of the inside of a
belted chamber machine with a sealing bar in an open position;
[0030] FIG. 2b illustrates a schematic view of the inside of a
belted chamber machine with a sealing bar in a closed position;
[0031] FIG. 3a illustrates a schematic view of the inside of a
belted chamber machine with two oppositely situated sealing bars in
an open position,
[0032] FIG. 3b illustrates a schematic view of the inside of a
belted chamber machine with two oppositely situated sealing bars in
a closed position,
[0033] FIG. 4 illustrates a time/temperature and a time/pressure
graph of a method according to the disclosure;
[0034] FIG. 5 illustrates a time/temperature and a time/pressure
graph in a variant; and
[0035] FIG. 6 illustrates a time/temperature and a time/pressure
graph in a further variant.
DETAILED DESCRIPTION
[0036] In the figures identical components are designated with the
same reference numerals throughout.
[0037] FIG. 1 illustrates an embodiment of a belted chamber machine
1 with a feed belt 2 on which bags, which are not illustrated, are
deposited filled with products. The belted chamber machine has a
transport direction R, an insertion end E and an exit end A. In its
lowered position, which is not illustrated, a chamber upper part 3
with a machine table 4 forms a closed chamber which can be
evacuated. A controller 14 controls the processes of the belted
chamber machine 1, displays operational information to an operating
person and is used for the operating person to make entries.
[0038] FIG. 2a illustrates a bag 6 and a product 7. The product 7
in the bag 6 is inserted into a chamber machine or several bags are
fed to a belted chamber machine 1 via the feed belt 2. Then the
chamber is closed and a vacuum is produced inside the chamber in
order to evacuate the bag 6. Here, a neck 8 of the bag is located
between a sealing bar 9 and a counter-pressure strip 10. During the
evacuation process of the chamber the sealing bar 9 is located in
an open position so that the inside of the bag 6 is also evacuated.
Once the evacuation is terminated in that a vacuum value set by the
operating person is reached, the sealing bar 9, as illustrated in
FIG. 2b, is moved against the counter-pressure strip 10 and a
contact pressure P1 is produced so that the sealing bar 9 comes
into contact with the bag 6 and the heat is transferred from the
sealing bar 9 to the bag 6. The heating of the sealing bar 9 is
realised by means of electrical resistance heating elements, for
example, sealing wire. The sealing bar 9 is heated to a first
temperature T1 before or during the contact with the neck 8 of the
bag. Due to the heating of the product residues 11 in the region 12
of the sealing weld to a first temperature T1, the liquid part 11'
of the product parts 11 vaporises and escapes from the region 12.
This first temperature T1 is lower than a sealing temperature Ts of
the packaging material in order to prevent premature sealing. For
the subsequent sealing the temperature of the sealing bar 9 is
raised to the sealing temperature Ts and also a sealing pressure Ps
between the sealing bar 9 and the counter-pressure strip 10 is
produced during a defined period.
[0039] It is also conceivable that the contact pressure P1 is the
sealing pressure Ps right from the start.
[0040] FIGS. 3a respectively 3b illustrate a variant of FIGS. 2a
respectively 2b in which, instead of an unheated counter-pressure
strip 10, a further heatable sealing bar 13 is present. After
producing the contact pressure P1 of the sealing bar 9 on the
sealing bar 13, the heat is transferred from the sealing bars 9 and
13, which are heated to the first temperature T1, from both sides
onto the bag 6. This gives an efficient and fast heat transfer onto
the bag 6. The time for this process or for maintaining the
temperature in the sealing bars 9 and 13 at the first temperature
T1 can be set by the operating personnel and is regulated by the
controller 14.
[0041] The increase of the temperature on the sealing bars from the
first temperature T1 to the sealing temperature Ts can be carried
out before, simultaneously or after the increase in pressure from
the contact pressure P1 to the higher sealing pressure Ps.
[0042] FIG. 4 illustrates a t/P (time/pressure) and a t/T
(time/temperature) graph which relates to the embodiment of the
FIGS. 2a and 2b, respectively 3a and 3b.
[0043] The method according to the disclosure provides for a
variant in which the sealing bars 9 and 13 crimp the bag 6 and a
first temperature T1 is transferred to the bag 6 by the contact
with it during the (holding) time t1. The temperature T1 is higher
or equal to a product temperature Tp which must at least be
attained in order to change the state of aggregation of the product
parts 11. This is preferably carried out until the product parts
11, 11' have escaped from the region 12 of the sealing weld to be
produced to an extent adequate for the sealing. For the sealing the
temperature of the sealing bars 9 and 13 is raised to the
temperature Ts and maintained over the period ts. Thereafter the
sealing bars 9, 13 are cooled to an initial temperature Ta which
corresponds to the ambient temperature. The sealing bars 9, 13 are
here cooled by means of cooling water which passes through cooling
holes in the sealing bars 9, 13. Here, the sealing bars 9 and 13
are first moved away from one another once the temperature has
reduced and cooling and thus hardening of the sealing weld has
taken place. In this way the risk of the sealing weld adhering to
the sealing bars 9, 13 is reduced.
[0044] The graph in FIG. 5 illustrates in relation to a second
variant that the sealing bars 9, 13 are heated to a pre-heating
temperature Tv before the sealing bars 9, 13 are moved together in
order to attain the first temperature T1 quickly. Following that,
the sealing bars 9, 13 are brought into contact with the packaging
material and a contact pressure Ps is established. After the
sealing process, cooling occurs to the pre-heating temperature Tv
or to a cooling temperature Ta which can correspond to the ambient
temperature. The temperature increase from Tv to T1 can also occur
simultaneously or partially overlapping in time with the pressure
increase to Ps.
[0045] The sequence of the method is illustrated in a further
variant in FIG. 6. Here, a contact pressure P1 is set for the
displacement of the product parts 11, 11'. This contact pressure P1
can act during the time t1, but also before or after the heating of
the sealing bars 9, 13 to the first temperature T1. The increase in
the contact pressure P1 to the sealing pressure Ps can be carried
out simultaneously with the temperature increase to Ts. However,
also other variants are conceivable which are not illustrated and
in which the pressure increase occurs after or before the
temperature increase from the first temperature T1 to the sealing
temperature Ts.
[0046] Cooling takes place to a cooling temperature Ta which
preferably corresponds to the ambient temperature or which is set
by the active cooling of the sealing bars 9, 13. At the start of a
new packaging process the sealing bar 9, 13 is heated to the
pre-heating temperature Tv.
[0047] The method according to the disclosure is not restricted to
the previously described processes. The pressure increase to the
contact pressure Ps or P1 can also occur before, during or after
the heating of the sealing bars 9, 13 to T1 or Ts.
[0048] The pre-heating temperature Tv can also be equal to the
first temperature T1 at the start of the packaging process.
[0049] In a preferred variant the temperature closed-loop control
of the sealing bars 9 and 13 occurs using the controller 14 in the
same form in order to improve the effect during the packaging
process and to speed it up, leading to an increase in the
performance of the packaging machine.
[0050] While embodiments of the disclosure have been illustrated
and described, it is not intended that these embodiments illustrate
and describe all possible forms of the disclosure. Rather, the
words used in the specification are words of description rather
than limitation, and it is understood that various changes may be
made without departing from the spirit and scope of the
disclosure.
* * * * *