U.S. patent application number 16/978686 was filed with the patent office on 2021-02-11 for vacuum skin packaging.
The applicant listed for this patent is LINPAC PACKAGING LIMITED. Invention is credited to Julian BURGESS, Alan DAVEY, Stuart FRASER, Craig HARDWICK, Tom HIRST, Richard KERSHAW, Paul RAWLINGS.
Application Number | 20210039861 16/978686 |
Document ID | / |
Family ID | 1000005223756 |
Filed Date | 2021-02-11 |
![](/patent/app/20210039861/US20210039861A1-20210211-D00000.png)
![](/patent/app/20210039861/US20210039861A1-20210211-D00001.png)
![](/patent/app/20210039861/US20210039861A1-20210211-D00002.png)
![](/patent/app/20210039861/US20210039861A1-20210211-D00003.png)
![](/patent/app/20210039861/US20210039861A1-20210211-D00004.png)
![](/patent/app/20210039861/US20210039861A1-20210211-D00005.png)
![](/patent/app/20210039861/US20210039861A1-20210211-D00006.png)
![](/patent/app/20210039861/US20210039861A1-20210211-D00007.png)
![](/patent/app/20210039861/US20210039861A1-20210211-D00008.png)
![](/patent/app/20210039861/US20210039861A1-20210211-D00009.png)
![](/patent/app/20210039861/US20210039861A1-20210211-D00010.png)
View All Diagrams
United States Patent
Application |
20210039861 |
Kind Code |
A1 |
KERSHAW; Richard ; et
al. |
February 11, 2021 |
VACUUM SKIN PACKAGING
Abstract
A container for vacuum skin packaging a product is provided. The
container includes a surface for supporting the product and one or
more vacuum vents, wherein the one or more vacuum vents are
separated from the supporting surface by one or more separation
walls. A process for vacuum skin packaging a product using the
container and a process for forming the container are also
provided.
Inventors: |
KERSHAW; Richard; (Ossett,
West Yorkshire, GB) ; HIRST; Tom; (Scissett,
Huddersfield, GB) ; RAWLINGS; Paul; (Smolec, PL)
; HARDWICK; Craig; (Wakefield, West Yorkshire, GB)
; BURGESS; Julian; (Strensall, GB) ; FRASER;
Stuart; (Sheffield, South Yorkshire, GB) ; DAVEY;
Alan; (Gateforth, Selby, North Yorkshire, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LINPAC PACKAGING LIMITED |
Pontefract, West Yorkshire |
|
GB |
|
|
Family ID: |
1000005223756 |
Appl. No.: |
16/978686 |
Filed: |
February 25, 2019 |
PCT Filed: |
February 25, 2019 |
PCT NO: |
PCT/GB2019/050503 |
371 Date: |
September 5, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65D 1/34 20130101; B65D
75/305 20130101; B65B 11/52 20130101; B65D 81/2015 20130101; B65D
2543/00296 20130101 |
International
Class: |
B65D 75/30 20060101
B65D075/30; B65D 81/20 20060101 B65D081/20 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 5, 2018 |
GB |
1803513.9 |
Claims
1. A container for vacuum skin packaging a product, comprising a
surface for supporting said product and one or more vacuum vents,
wherein the one or more vacuum vents are separated from the
supporting surface by one or more separation walls.
2. The container according to claim 1, wherein the one or more
vacuum vents are formed in one or more walls of the container.
3. The container according to claim 1, wherein the one or more
separation walls extend substantially perpendicularly from the one
or more walls of the container.
4. The container according to claim 1, wherein the one or more
vacuum vents are located within a well, so as to isolate the one or
more vacuum vents from the supporting surface.
5. The container according to claim 1, wherein the one or more
vacuum vents are formed in a base of the well.
6. The container according to claim 1, wherein the one or more
separation walls comprise a single wall.
7. The container according to claim 1, wherein the one or more
separation walls comprise a plurality of walls.
8. The container according to claim 7, wherein the one or more
separation walls comprise two walls.
9. The container according to claim 1, wherein the one or more
separation walls comprise an air evacuation passage.
10. The container according to claim 9, wherein the air evacuation
passage is of greater dimensions than the one or more vacuum
vents.
11. The container according to claim 9, wherein the air evacuation
passage comprises a recessed area.
12. The container according to claim 1, wherein the one or more
vacuum vents are located in a plane extending from the supporting
surface of the container.
13. The container according to claim 1, wherein the container
comprises one or more corners and one or more vacuum vents are
located in each corner of the container.
14. The container according to claim 1, wherein the one or more
vacuum vents are located in one or more side walls of the
container.
15. The container according to claim 1, wherein the one or more
vacuum vents comprise a hinged flap.
16. The container according to claim 1, comprising a monolayer of
material or multilayer sheet of material(s), said material(s) being
selected from virgin or recycled polymeric material(s) such as
virgin or recycled polyethylene terephthalate (PET), polypropylene
(PP), carton board and pulp, aluminium, or plant-based plastic
alternatives.
17. A process for vacuum skin packaging a product, comprising the
steps of: a) providing a container according to claim 1, b)
positioning the product onto a supporting surface of the container,
c) positioning a film above the product and the container, d)
evacuating air by application of vacuum so that the film contacts
the product and the supporting surface of the container.
18. The process according to claim 17, wherein the container
comprises one or more vacuum vents separated from the supporting
surface by one or more separation walls and comprising the step of
contacting the film to the one or more separation walls before
contacting the film to the one or more vacuum vents.
19. A process for forming a container according to claim 17,
comprising the steps of: a) producing the container comprising the
surface for supporting a product, b) producing one or more
separation walls, c) producing the one or more vacuum vents,
wherein the one or more vacuum vents are separated from the
supporting surface by one or more separation walls.
20. The process according to claim 17, comprising the step of
thermoforming the container from a sheet of plastics
material(s).
21. The process according to claim 17, comprising the step of
thermoforming or stamping the one or more separation walls from a
sheet of plastics material(s).
22. The process according to claim 17, wherein the one or more
vacuum vents comprise a hinged flap.
23. The process according to claim 17, comprising the step of
punching or perforating the container to form one or more vacuum
vents.
24. The process according to claim 17, wherein the process is a
continuous process.
Description
[0001] The present invention relates to containers suitable for use
in the packaging, storage, transportation and/or display of a
product, such as a fresh food product, and to processes for making
such containers. More particularly, the present invention relates
to containers for the vacuum skin packaging of products and
corresponding processes.
[0002] It is known to use plastic containers to package, store,
transport and display fresh food. These containers may be sealed
with a lidding film to protect the food within the container from
the surrounding environment. Alternatively, the products can be
packaged by way of known vacuum packaging processes.
[0003] Vacuum skin packaging processes are widely used for
packaging fresh products such as meat, poultry, fish, cheese and
the like. In conventional vacuum skin packaging processes, the
product to be packed is placed onto a tray or container, which may
be flat or shallow with low walls. The product and tray or
container is placed into a vacuum chamber that provides support at
strategic points (usually under the flange and/or the base of the
tray or container). The vacuum chamber is connected to a vacuum
pump that when energised, evacuates the air from the chamber and
from around the product being packed resulting in the vacuum skin
effect. A film is positioned above the product, whereby the film is
drawn upwards and held against a heated plate or dome, producing a
combination of air and vacuum on opposing sides of the film. The
film is heated by direct thermal transfer (contact heating). Once
the film is heated it is released and the air between the product
and the film is evacuated. The film is drawn downwards until the
film contacts the product and the support thereby forming a tight
"skin" around the product and a seal with the support. In order to
achieve a homogeneous and effective removal of the air, this step
must be carried out gently and relatively slowly. The air is
evacuated through the spaces between the film and the support, more
particularly over the edges or flanges of the support, and once the
film seals the edges of the support, the air can no longer escape.
Rushing this step could result in the premature seal of the edges
of the support and the formation of air pockets which will decrease
the shelf-life of the product. This is therefore a very slow step
in an otherwise high speed packing process.
[0004] Processes in which the support comprises apertures are
described for example in EP 2 735 525 and EP 0 320 294. In these
documents, the support is a deep container with a base and side
walls extending from said base. Apertures are provided in the side
walls so that, as vacuum is applied from below the support, the air
between the film and the support is evacuated conventionally
through the space between the film and the edge of the support and
then through the apertures in the side walls once that space is
sealed.
[0005] The apertures of the prior art containers are located in
close proximity to the flange or mouth of the container.
Accordingly, there is only a short period of time between the film
contacting (1) the flange or mouth of the container and (2) the
apertures. Therefore, the apertures are prematurely sealed by the
film, minimising the volume of air evacuated through the apertures
and slowing down the sealing process. Consequently, the risk of air
pockets remaining between the film and the support still exists.
Therefore, the film does not seal tightly around the packaged
product and visible air pockets are unappealing.
[0006] It is an object of this invention to mitigate problems such
as those described above and to increase the speed at which the
vacuum packaging process can be undertaken.
[0007] According to a first aspect of the invention, there is
provided a container for vacuum skin packaging a product,
comprising a surface for supporting said product and one or more
vacuum vents, wherein the one or more vacuum vents are separated
from the supporting surface by one or more separation walls.
[0008] The container according to the present invention is
advantageously used for packaging food products, in particular
meat, fish or cheese, or any other moisture-containing product
susceptible to leakage of juices or other liquids. In the
containers described in the prior art, any juice seeping from the
product could leak through the apertures during the air evacuation
step of the sealing process. This problem is alleviated by the
container according to the present invention because the vacuum
vents are separated by a separation wall from the supporting
surface, effectively acting as a dam or a barrier against product
juice contamination. Consequently, the risk of leakage of product
juice into the vacuum vents, or contamination and/or blockage of
the vacuum vents by juice or debris is minimised or prevented
altogether, due to the protection of the vacuum vents by the
separation wall. It is therefore possible, for example, to avoid
(a) contamination of the sealing equipment with juices from the
product, (b) contamination and/or blockage of the vacuum vents, and
(c) contamination of other containers in the packing chain.
[0009] Another advantage of the container according to the present
invention is that it improves the packing process and, in
particular, it accelerates the sealing step without compromising
the quality of the seal. As explained above, the skin film is drawn
upwards and positioned above the product and the supporting
surface, and heated. The air between the product and the film held
above the product is then evacuated by application of vacuum from
below the container. During this air evacuation process in the
present invention, the film contacts and adheres to the structures
of the container and the product in a sequential order starting
from the uppermost parts. For example, the film contacts the flange
or the mouth of the container, then the top of the contained
product, then the side walls, then the supporting surface and the
protective wall(s) so that the last structure to be the film
adheres to is the vacuum vents. Thereby effectively sealing the
vacuum vents last, and achieving a total pack seal.
[0010] Preferably, the one or more vacuum vents are formed in one
or more walls of the container (e.g. the base and/or side walls).
In a preferred embodiment, the one or more vacuum vents are formed
in the supporting surface or in the plane extending from the
supporting surface.
[0011] Preferably, a separation wall extends from the container
wall on which its corresponding vacuum vent(s) is/are located. For
example, if the vacuum vent is formed in the base, then the
separation wall(s) preferably extends from the base; if the vacuum
vent is formed on a side wall, divider wall, peripheral flange, or
column as will be described below, then the separation wall(s)
extends from said side wall, divider wall, peripheral flange, or
column, respectively. Preferably, the separation wall forms a
complete or partial barrier around the vacuum vent(s). More
preferably, the separation wall forms a partial or complete barrier
at or around the perimeter of the vacuum vent(s). Preferably, said
one or more separation walls extend substantially perpendicularly
from one or more walls of the container. The separation wall(s)
protects the vacuum vents from any juices leaking from the food
product by forming a physical barrier in the manner of a dam or a
barrier. In addition, during the vacuum process, the skin film will
contact the protective wall so as to delay the sealing of the
vacuum vents.
[0012] The present invention is particularly advantageous for
vacuum skin packaging products in a container comprising one or
more side walls extending from the supporting surface or base (as
opposed to vacuum skin packaging using a flat support). In a
preferred embodiment, one or more vacuum vents are formed in the
plane extending from the supporting surface and said vents are
isolated from the supporting surface by a separation wall extending
substantially perpendicularly from the supporting surface.
[0013] A problem identified in the prior art associated with the
sealing process is that once the film contacts the supporting
surface of the container, air can no longer be evacuated. This is
of particular relevance for deep containers or containers with
non-standard shapes, as the space between the film and the air
evacuation pathway can become sealed prematurely. Air pockets may
remain trapped between the film and the supporting surface, which
are unsightly and reduce the shelf-life of the product.
[0014] The vacuum vents may be formed within the container, e.g. on
the plane extending from the supporting surface, or alternatively
they can be formed on a side wall, a divider wall dividing the
container into two or more compartments, or a column extending
substantially perpendicularly from the supporting surface, or a
flange extending around the outer periphery of the container. In a
preferred embodiment, the vacuum vents are positioned below the
level of the mouth of the container.
[0015] In a preferred embodiment, the one or more vacuum vents are
located within a well, so as to isolate the one or more vacuum
vents from the supporting surface. Preferably, the one or more
vacuum vents are formed in a base of the well.
[0016] More generally, the separation wall forms a compartment, for
example in the form of a well, within which one or more vacuum
vents are formed. In other words, the separation wall forms a
compartment or a well by enclosing the vacuum vent(s), and
effectively acts as a bailey or a dam or a barrier. The separation
wall can completely surround the vacuum vent(s). Alternatively, the
separation wall can surround the vacuum vent(s) together with the
side wall of the container so as to form a compartment, for example
in the form of a well. The wall of the compartment or well shields
the vacuum vents, providing the advantage of preventing any juices
or debris from the product from contaminating or blocking the
vacuum vents.
[0017] The inner space of the well or compartment may have a
substantially circular, oval, triangular square or rectangular
horizontal cross section. More preferably, the inner space of the
well or compartment has a substantially ovoid, teardrop-, egg-, or
pear-shaped cross section. Preferably, the well or compartment has
an asymmetrical cross section. In a preferred embodiment, the inner
space of the well or compartment has an asymmetrical ovoid or
pyriform cross-section. Preferably, the container comprises one
vacuum vent at each corner of the container. More preferably, the
vacuum vent is formed in the base of the larger half of an ovoid or
pyriform well or container. The vacuum vents are isolated from the
product packaged in the container and also serve as a denesting
feature as will be explained below in more details.
[0018] In another embodiment, the one or more separation walls
comprise a single wall. For example, the separation wall may extend
from a container wall or base as a flat single-walled partition
wall. Alternatively, the one or more separation walls may comprise
a plurality of walls, preferably two walls. The separation wall may
comprise a double-walled rib, for example one formed by an
undulation of the container wall or base. In a preferred
embodiment, the separation wall forms a substantially triangular
shape, together with two adjacent side walls of the container so
that the separation wall and side walls partially or completely
surround the vacuum vent.
[0019] Preferably, the upper, in use, edge of the separation wall
extends to the side wall so as to define the mouth of the well or
compartment. Preferably, the extension is substantially parallel to
the supporting surface. In a preferred embodiment, the extension
comprises two portions of different shapes so as to define an
asymmetrical mouth of the well or compartment.
[0020] In a preferred embodiment, the one or more separation walls
comprise an air evacuation passage. The air evacuation passage is
created when the film touches and seals to the outside upper (in
use) surfaces of the separation wall. As the central area of the
separation wall is lower than the outside upper (in use) surfaces
of the separation wall, the air evacuation passage is now the only
channel for air to flow through. The characteristics of the
packaging machine vacuum pump remain constant through the vacuum
skin packaging cycle, which means that the air flow rate through
the air evacuation passage is increased, due to the fact that the
cross section of the channels is now smaller than when the air was
able to flow over the walls into the vacuum vents. The increased
air flow chills the film immediately above the air evacuation
passage (effectively the upper (in use) surface of the air
evacuation passage), making the film less plastic (i.e. the film is
less easily shaped or moulded, less malleable, less pliable or less
pliant). A less plastic film is less inclined to be manipulated or
move. In this way, the channel is maintained open for longer,
allowing as much air as possible to be evacuated from the
container. When all remaining air is extracted from the tray and
around the packed product, the air flow falls to zero and the final
part of the skinning film collapses and seals off the channel.
Accordingly, the film is prevented from collapsing and contacting
(and/or blocking) the vacuum vent(s) until the final moments of the
air evacuation process, i.e. the time point at which the maximum of
volume of air has been evacuated from the container.
[0021] Preferably, the air evacuation passage is of greater
dimensions than the one or more vacuum vents. For example, the air
evacuation passage has a larger surface area than the vacuum
vent(s). During the air evacuation process, the air is evacuated
from the inner region of the container, towards the air evacuation
passage. The air evacuation passage is advantageous in that it
induces the velocity of the air stream (i.e. the flow rate) to
increase in the direction of the vacuum vent(s). In other words,
the air stream accelerates through the air evacuation passage
towards the vacuum vent(s), resulting in a more efficient air
evacuation process. The velocity of the air increases further once
it passes through the vacuum vent(s) (i.e. the final structure of
the container through which air is evacuated), due to the
dimensions of the air evacuation being greater than those of the
vacuum vents.
[0022] Preferably the air evacuation passage comprises a recessed
area. More preferably the air evacuation passage comprises a dip
in, or a channel through the uppermost in use edge of the
separation wall.
[0023] Preferably, the one or more vacuum vents are located in a
plane extending from the supporting surface of the container.
Hence, the vacuum vents are preferably located at the same level as
the supporting surface of the container. In a preferred embodiment,
if the vacuum vent(s) are located in a compartment, then the base
of the compartment is in the same plane as, or level with the
supporting surface. An advantage of this feature is that the
container and the product are efficiently supported during and
after the packing process. For example, there may be a support
below the supporting surface so that the vacuum vent(s) are not
hindered during the vacuum step.
[0024] Within the context of the present invention, it is envisaged
that the vacuum vents are positioned below the level of the
supporting surface, or above the level of the supporting surface,
provided the wall(s) keep the vacuum vents separated from the
supporting surface.
[0025] Preferably, the container comprises one or more corners and
the one or more vacuum vents are located in each corner of the
container. For example, the container may have a square or
rectangular base. It has been identified in the prior art that
during the vacuum sealing process, the film contacts the surface of
the container in the corner locations later than in comparison with
the other areas of the side walls. Accordingly, locating the one or
more vacuum vents in the corner of the container will facilitate an
increased amount of air to be evacuated from within the container.
In addition, when the vacuum vents are located in a corner of the
container they are positioned away from the contained product and
its juices. As a result, the positioning of the one or more vacuum
vents minimises the risk of contamination and/or blockage of the
vents by the juices of the product.
[0026] Additionally and/or alternatively, the one or more vacuum
vents are located in a plane different from the plane extending
from the supporting surface of the container. This is advantageous
in circumstances where the shape of the product and/or container
render vacuum vents located at the same level as the supporting
surface unsuitable, or if the vacuum is applied from a location
different than from underneath the container or from multiple
directions.
[0027] Preferably, the one or more vacuum vents are located in one
or more side walls of the container. These vacuum vents may be
provided with or without a protective separation wall. It is
envisaged that the vacuum vents are formed in the side walls of the
container and surrounded as described above by a protective
separation wall. However, a vacuum vent formed in the side wall
could be prematurely sealed during the vacuum process. In addition,
the protective separation walls around said vacuum vents could
themselves cause air pockets to form by creating shielded areas
from which it is difficult to remove air. It is therefore preferred
that the container comprises one or more vacuum vents are formed
in, at or below the level of the supporting surface.
[0028] Preferably, the one or more vacuum vents comprise a hinged
flap. In conventional containers, apertures are created by punching
a hole through the wall of the container, thereby detaching small
pieces of material from the container which must be removed in
order to prevent contamination. The high-speed high-throughput
process and the small size of the detached material makes it
difficult to keep the packing environment clean. Once the vacuum
vent has been punched through the wall of the container, the hinge
is of sufficient flexibility to prevent the premature and/or
accidental closure of the vacuum vents. Where the flap is directed
towards the (in use) inside of the container, the flap prevents the
film from closing and/or blocking the vacuum vents until all of the
air has been evacuated, i.e. the final moments of the air
evacuation process. Similarly, where the flap is directed towards
the (in use) outside of the container, the flap prevents accidental
closure and/or blockage of the vacuum vents.
[0029] As a result, the presence of this skeletal waste increases
the risk of contamination of the product, subsequently decreasing
the shelf-life of the product and/or causing the product to be
unsafe for use. The skeletal waste may also contaminate other
products in the supply line, and/or the sealing equipment.
Furthermore, open holes may potentially allow air and other
particles to enter the container after completion of the vacuum
sealing process, therefore reducing the shelf-life of the product.
Additionally, skeletal waste is problematic, thorough cleaning of
the packing plant is required and the issues of environmental
impact and recycling arise.
[0030] In order to overcome this problem, the containers according
to the present invention are produced by partially perforating the
wall of the container so that the perforated material remains
attached to the container. Accordingly, the container is perforated
to create the hinged flap. The perforation does not require any
removal of material from the container; therefore the problems
relating to skeletal waste are circumvented. Additionally, the
hinged flap prevents air or other particles from (re-)entering into
the container after completion of the vacuum sealing process,
thereby maintaining a vacuum atmosphere within the container, and
prolonging the shelf-life of the product.
[0031] Preferably, the container comprises a monolayer of material
or multilayer sheet of material(s), said material(s) being selected
from virgin or recycled polymeric material(s) such as polyethylene
terephthalate (PET), polypropylene (PP), carton board and pulp,
aluminium, or plant-based plastic alternatives.
[0032] The advantages of these materials are that they are widely
known industrial standard materials and approved by the meat
packing industry. The majority of the materials are recyclable. The
features of the separation wall and vacuum vent operate
independently of the material(s) of which the container
comprises.
[0033] According to a second aspect of the invention, there is
provided a process for vacuum skin packaging a product, comprising
the steps of:
[0034] a) providing a container as described above,
[0035] b) positioning the product onto a supporting surface of the
container,
[0036] c) positioning a film above the product and the
container,
[0037] d) evacuating air by application of vacuum so that the film
contacts the product and the supporting surface of the
container.
[0038] In a preferred embodiment of the process, the container
comprises one or more vacuum vents separated from the supporting
surface by one or more separation walls and comprising the step of
contacting the film to the one or more separation walls before
contacting the film to the one or more vacuum vents.
[0039] In a most preferred embodiment, the sealing sequence
comprises the following steps:
[0040] 1. The film contacts and adheres to the flange or mouth of
the container.
[0041] 2. The film contacts and adheres to the top of the contained
product.
[0042] 3. The film contacts the side walls of the container
(gradually from top to bottom).
[0043] 4. The film contacts to the supporting surface.
[0044] 5. The film contacts and adheres to the protective
separation wall.
[0045] Lastly, the film contacts and adheres to the one or more
vacuum vents.
[0046] Preferably, the process for forming a container comprises
the steps of:
[0047] a) producing the container comprising a surface for
supporting a product,
[0048] b) producing the one or more separation walls,
[0049] b) producing the one or more vacuum vents, wherein the one
or more vacuum vents are separated from a supporting surface by one
or more separation walls. The container may be formed separately,
for example, at a packaging factory or on an integrated product
packaging line, i.e. where the container is formed on the same line
as the product is packaged, such as a form fill seal type line.
[0050] Preferably, the process comprises the step of forming the
container by thermoforming a sheet of plastics material(s).
Preferably, the process comprises the step of thermoforming or
stamping the one or more separation walls from a sheet of plastics
material(s). The advantages of thermoforming are that it is an
inexpensive and efficient process for forming containers. The
separation wall(s) are preferably integrally moulded to the
container.
[0051] In a preferred embodiment, the one or more vacuum vents
comprise a hinged flap. Preferably, the process comprises the step
of punching or perforating the container to form one or more vacuum
vents. Punching through the sheet of plastics material(s) creates a
strong hinge that cannot be closed easily by the film. The vacuum
vent covered by the hinged flap is made with large radii to
increase the closing strength of the hinged flap.
[0052] Preferably, the process for forming the container is a
continuous process. Continuous processes according to the present
invention are efficient, cost effective and achieve high-speed and
high-throughput, without compromising on the quality of the vacuum
seal. Accordingly, there are no air pockets, which are unsightly
and thus the shelf-life of the product is prolonged, without the
risk of contamination. However, within the context of the present
invention, it can also be envisaged that the process is a batch
process or a parallel process, for example, a form fill seal
process.
[0053] Within the context of the present invention, the term
"vacuum vent" includes an opening or aperture through the container
allowing passage of air between inside the container and outside
the container. The vent may be of any shape, pattern and/or
dimension to allow the evacuation of air from between the film and
the product/supporting surface.
[0054] Within the context of the present invention, the expression
"inside the container" refers to the space defined by the inner
surface of the container which is intended to receive the product
to be packaged. By contrast, the expression "outside the container"
refers to the space defined by the outer surface of the
container.
[0055] Within the context of the present invention, the expressions
"separation wall", "protective wall", "surrounding wall" are used
interchangeably to designate the wall separating the vacuum vent(s)
from the supporting surface. One wall may surround one or more
vacuum vents. A plurality of walls may surround one or more vacuum
vents. One or more vacuum vents may be surrounded by a separation
wall and a side wall of the container.
[0056] The invention will be further described with reference to
the drawings and figures, in which
[0057] FIG. 1 is a schematic representation (top view) of a
container according to the present invention;
[0058] FIG. 2 is a schematic representation (front view) of the
container of FIG. 1;
[0059] FIG. 3 is a schematic representation (bottom view) of the
container of FIG. 1;
[0060] FIG. 4 is a schematic representation (partial perspective
view) of the corner of the container of FIG. 1;
[0061] FIG. 5 is a schematic representation (partial top view) of
the corner of the container of FIG. 1;
[0062] FIG. 6 is a schematic representation (front view) of the
container of FIG. 1;
[0063] FIG. 7 is a schematic representation (perspective view) of
the bottom of the container of FIG. 1;
[0064] FIG. 8 is a schematic representation (perspective view) of
the container of FIG. 1;
[0065] FIGS. 9A and 9B are schematic representations (side views)
of the container of FIG. 1;
[0066] FIGS. 10A, 10B and 10C are partial (cross sectional)
schematic representations of a container according to the present
invention;
[0067] FIGS. 11A and 11B are partial (cross sectional) schematic
representations of separation walls formed in a container according
to the present invention;
[0068] FIG. 12 is a partial schematic representation of a
separation wall according to the present invention;
[0069] FIGS. 13a to 13e are schematic representations of denesting
elements used in a container according to the present
invention;
[0070] FIGS. 14a and 14b illustrate the positioning of the air
evacuation passage in a container according to the present
invention;
[0071] FIG. 15A is a schematic representation (perspective views)
of a second container according to the present invention;
[0072] FIG. 15B is a schematic representation (perspective views)
of a third container according to the present invention;
[0073] FIG. 16 is a schematic representation (perspective views) of
a fourth container according to the present invention;
[0074] FIG. 17 is a schematic representation (perspective views) of
a fifth container according to the present invention;
[0075] FIG. 18 is a schematic representation (perspective views) of
a sixth container according to the present invention; and
[0076] FIG. 19 is a schematic representation (perspective views) of
a seventh container according to the present invention.
[0077] Referring to FIG. 1, there is illustrated a container 1 for
vacuum skin packaging a product, comprising a surface 2 for
supporting said product and one or more vacuum vents 3, wherein the
one or more vacuum vents 3 are separated from the supporting
surface 2 by one or more separation walls 4.
[0078] The container 1 comprises a peripheral flange 11 surrounding
the mouth of the container 1. In use, including during packaging
and displaying the product, the container 1 is positioned with the
peripheral flange 11 being the uppermost structure. In other words,
the mouth of the container 1 is upwards and the supporting surface
2 and/or the base of the container 1 is down. In this embodiment,
the cross section of the container 1 is substantially rectangular
and comprises corners 8, but other shapes of container are
envisaged, such as circular, squares, triangle or less conventional
shapes to fit specific product shapes. The container 1 further
comprises a plurality of walls 5, including side walls 9 extending
from the supporting surface 2 and/or the base 7 of the well 6.
[0079] In the present embodiment, each corner 8 of the container 1
comprises a vacuum vent 3. Each vacuum vent 3 is separated from the
supporting surface 2 by a separation wall 4. The separation wall 4
acts a dam and is a barrier between the vacuum vents 3 and the
supporting surface 2 and the product (not shown). Thus, the
separation wall 4 protects the vacuum vents 3 and prevents
contamination of the vacuum vent 3 from any juices seeping from the
product.
[0080] With reference to FIG. 10A, the vacuum vents 3 are located
in a plane extending from the supporting surface 2. However, in
other embodiments (see FIGS. 10B and 10C), the vacuum vents 3 are
located in a plane different from the plane extending from the
supporting surface 2. For example, the vacuum vents 3 can be
located in a plane above (in use) the plane extending from the
supporting surface 2. Alternatively and/or additionally, the vacuum
vents 3 can be located in a plane below (in use) the plane
extending from the supporting surface 2. The dimensions, for
example, the height, of the separation wall 4 can be altered
accordingly.
[0081] The separation wall 4 extends from the supporting surface 2
and is integrally formed with the container 1. Preferably, the
separation wall extends from the supporting surface 2 in the shape
of a double-walled rib. In this embodiment, the vacuum vents 3 are
located at the corners of the container 1. One vacuum vent 3 is
located within a compartment, for example the well 6 of the
container 1. The well 6 is formed of a base 7 (in which the vacuum
vent is formed), the separating wall 4 and part of the side wall 9
of the container 1. However, the well 6 could equally be formed of
a separation wall 4 surrounding the vacuum vent 3, separate from
the side wall 9 of the container. The well 6 acts as a protective
barrier between the vacuum vent 3 and the supporting surface 2 and
the product.
[0082] Referring to FIG. 11A, the separation wall 4 can be a single
partitioning wall. In this embodiment the separation wall 4
comprises a single rib 12 extending from the container 1, and the
rib 12 partially surrounds the base 7 of the well 6. In another
embodiment, the separation wall 4 comprises a double-walled rib 13
(FIG. 11B). The double-walled rib 13 can extend partially or fully
around the perimeter of the well 6. Additionally and/or
alternatively, the double-walled rib 13 follows the contour of the
side wall 9 and/or the corner 8 of the container 1 so as to provide
additional support and rigidity during the packing process, and
subsequently during handling, transport, storage, display and use
of the container 1. This specific shape also strengthens the
structure of the well 6 during the sealing process, in particular
during the vacuum step. This is because during the vacuum step, the
container 1 is mostly supported from under the supporting surface
2. The base 7 of the well 6 is unsupported or partially supported
so as to leave the vacuum vents 3 unhindered. Therefore, when
vacuum is applied, the corners 8 of the container 1 comprising the
separation wall(s) 4 can withstand a fair degree of pressure.
[0083] Referring to FIG. 12, the specific profile of the upper (in
use) edge 14 of the separation wall 4 creates an air evacuation
passage 4a. In this embodiment, the specific profile of the upper
(in use) edge 14 of the separation wall 4 creates a recessed area
4b, or a channel or a dip through which air can form an accelerated
stream during the air evacuation process. The accelerated air flow
holds the film in a raised position in order to keep the film
elevated and away from the vacuum vent(s) 3 until the final moments
of the air evacuation process. The air evacuation passage 4a, or
channel or dip can be formed within the separation wall 4.
Preferably, a dip in the separation wall 4, together with the film
at or above the uppermost (in use) edge 14 of the separation wall
4, can form the air evacuation passage 4a.
[0084] The velocity of air in the region of the air evacuation
passage 4a is higher than in other inner regions of the container 1
and therefore the film is prevented from collapsing and sealing off
the air evacuation passage 4. The higher velocity air also chills
the film immediately above the air evacuation passage 4a, making
the film less plastic (i.e. the film is less malleable or flexible)
preventing premature sealing of the film to the separation wall 4
and/or the vacuum vents 3.
[0085] The air evacuation passage 4a causes the air stream to
accelerate in the direction of the vacuum vents 3, facilitating the
efficient evacuation of air from the container 1. The accelerated
air stream formed by the evacuation passage 4a prevents the film
from closing until all of the air within the container 1 has been
evacuated. Additionally, the air evacuation passage 4a causes the
velocity of air flowing from the inner region of the container 1 to
accelerate prior to evacuation of the air via the vacuum vents 3.
This is particularly advantageous at the end of the vacuum sealing
step, where the majority of the air has been evacuated. The air
flow is accelerated so as to quickly and efficiently remove the
final remnants of air.
[0086] The base 7 of the well 6 is shaped so as to follow the
contour of the container 1 and of the inner contours of the
separating wall 4. A vacuum vent 3 is located in the base of the
well 6. In the present embodiment, the vent 3 is offset from the
centre of the base 7 of the well 6. However, it can be positioned
centrally or it can form the whole base 7 of the well 6.
[0087] With reference to FIG. 4, the separation wall 4 comprises a
middle portion 15a, in which the air evacuation passage 4a is
formed. The upper edge of the separation wall 4 extends,
substantially parallel to the supporting surface 2, to the side
wall 9 of the container, so as to define the mouth of the well 6.
In this embodiment, the mouth of the well 6 is asymmetrical so that
the extension comprises one larger 15b side portion and one smaller
side portion 15b, on either side of the mouth of the well 6.
[0088] As mentioned above, the well 6 and the separation wall 4
also serve as a denesting feature to prevent nested containers from
being stuck to each other. Preferably, the denest feature is a
AB-type denesting feature, in which the denest element of a first
top container is different from the denest element from a second
bottom container. The containers according to the present invention
comprise denest elements such that the denest element of a first
bottom container in a pile of nested container, is formed at a
45.degree. angle relative to the corresponding denest element of a
second top container nested in said first container. In a preferred
embodiment, the denest element of a first bottom container in a
pile of nested container, is formed as a mirror image of the
corresponding denest element of a second top container nested in
said first container. In a most preferred embodiment, the denest
element of a first bottom container in a pile of nested container,
is formed at a 45.degree. angle relative to the corresponding
denest element of a second top container nested in said first
container and is formed as a mirror image to said second denest
element, as illustrated in FIGS. 1 and 13a to 13e.
[0089] The air evacuation passage 4a is formed in the separation
wall 4 so as to be aligned with the well 6 as illustrated in FIGS.
14a and 14 b and to enable efficient air flow from the containing
space of the container 1 to the well 6, through the vacuum vent 3.
Preferably, the middle portion 15a of a first bottom denest element
is formed as a mirror image of the corresponding middle portion 15a
of a second top container nested in said first container (also
shown in FIGS. 14a and 14b).
[0090] Whether the separation wall 4 is single-walled or formed
with a plurality of walls it is preferred that it is integrally
formed for robustness, to prevent deformation during the vacuum
step and so that the manufacturing process is simpler and less
costly.
[0091] The vacuum vents 3 comprise a hinged flap 10. The hinged
flap 10 is produced by punching or perforation of the container 1.
The cross-section of the hinged flap 10 in a horizontal plane
perpendicular to the container 1 (in use) is a semicircle, whereby
the straight, non-perforated/non-punched edge of the semicircle
forms the hinge. However, other shapes of hinged flap are
envisaged, including square and rectangular. Each hinged flap 10 of
the vacuum vent 3 is formed in the base 7 of the well 6.
Accordingly, the vacuum vent 3 and hinged flap 10 are positioned at
the lowermost location of the well 6 of the container 1 (in use).
Each vacuum vent 3 is formed in the base 7 of a well 6. In this
embodiment, the area of vacuum vent 3 and thus the hinged flap 10
is smaller than the area of base 7 of the well 6. Therefore, the
vacuum vent 3 and the hinged flap 10 do not cover the entirety of
the base 7.
[0092] The container 1 according to the present invention can be
produced by thermoforming. The container 1 comprises a monolayer or
multilayer sheet of material(s), said material(s) being selected
from virgin or recycled polymeric material(s) such as virgin or
recycled polyethylene terephthalate (PET), polypropylene (PP),
carton board and pulp, aluminium, or plant-based plastic
alternatives.
[0093] In use, the container 1 is formed by thermo-forming a sheet
of plastics material(s). The container 1 comprises a monolayer or
multilayer sheet of material(s), said material(s) being selected
from virgin or recycled polymeric material(s) such as such as
virgin or recycled polyethylene terephthalate (PET), polypropylene
(PP), carton board and pulp, aluminium, or plant-based plastic
alternatives. A product is placed on the supporting surface 2 of
the container 1 and the supported product is placed in a vacuum
chamber.
[0094] A film (not shown) is positioned above the supported product
and the container 1, for example by being drawn upwards by applying
a vacuum, to form a dome shape above the container 1. The film is
heated at temperatures ranging from 160.degree. C. to 240.degree.
C., which are high enough so that the film material softens. The
film is then sucked downwards towards the product and the support,
preferably by application of vacuum.
[0095] The film contacts and adheres to the structures of the
container 1 and the product in a sequential order starting from the
uppermost structures (in use). For example, the film contacts the
flange 11 of the container 1, then the top of the contained
product, then the side walls 9, then the supporting surface and the
protective separation wall(s) 4 so that the last structure to be
the film adheres to is the vacuum vents 3. The sealing sequence is
therefore as follows: [0096] 1. The film contacts and adheres to
the flange 11 or edges of the container 1. This is of particular
significance for deep containers where (a) there is a larger volume
of air to be evacuated and (b) the film has an increased distance
to travel. [0097] 2. The film contacts and adheres to the top of
the contained product between the flange 11 and the supporting
surface 2. [0098] 3. The film contacts the side walls 9 of the
container 1 (gradually from top to bottom). In the prior art
containers comprising apertures in close proximity to the flange,
it will be at this point in the air evacuation process that the
apertures are contacted by the film and closed off. Accordingly,
the apertures can no longer evacuate air after closure by the film.
Thus, there is still a risk that air pockets will remain and
consequently that the shelf-life of the product will be reduced.
[0099] 4. The film contacts to the supporting surface 2. [0100] 5.
The film contacts and adheres to the protective separation wall 4.
[0101] 6. Lastly, the film contacts and adheres to the one or more
vacuum vents 3.
[0102] Therefore, the one or more vacuum vents 3 are the final
structure(s) to be contacted and adhered to by the film due to the
presence of the surrounding separation wall 4. Accordingly, the
vacuum vents 3 are the final structure around which air is
evacuated, it is therefore possible to accelerate the sealing
process without compromising on the quality and homogeneity of the
sealing, thus providing for a fast, efficient and forgiving sealing
step.
[0103] Owing to the structure of the container 1 according to the
present invention, the sealing step, and therefore the vacuum skin
packaging process as a whole, can be carried out at high speed
without compromising the quality of the seal. However fast the
sealing step is carried out, the film will sequentially adhere to
the surfaces of the container 1 and seal the vacuum vents 3 last.
The product can be packaged without any unsightly air pockets,
without decreasing the shelf-life, and without contamination from
juices seeping from the product during the vacuum step.
[0104] FIGS. 15 to 19 illustrate further embodiments of containers
according to the present invention, wherein vacuum vents are
provided which are separated from the supporting surface by one or
more separation walls. A detailed description of features which may
be included in the containers according to the present invention
are described above and the following paragraphs provide
information on additional or alternative features of containers
according to the present invention.
[0105] FIG. 15A shows a container 101 for vacuum skin packaging a
product comprising a surface 102 for supporting said product and
one or more vacuum vents 103, wherein the one or more vacuum vents
are separated from the supporting surface by one or more separation
walls 104. The container 101 may further comprise ribs or shelves
120 extending from one or more side walls 109. The ribs or shelves
120 prevent the product and/or its juices from blocking the vacuum
vents 103. In this embodiment, elongated shelves 120 extend from
each of the four side walls 109. Each shelf 120 comprises a
platform 121, side walls 122 and a front wall 123 extending from
the edges of said platform. The side walls 122 may extend
perpendicularly or non-perpendicularly from the platform 121 edges.
The edges of each shelf 120 are rounded so as to avoid damage to
the product. The shelf 120 preferably extend along a side wall 109
of the container 101, from one separation wall 104 in a corner of
the container 120 to the separation wall 104 in the next corner of
the container 120.
[0106] The container of the present invention may also comprise one
or more divider walls 130 for dividing the supporting surface into
two or more compartments. In a preferred embodiment, the container
comprises one substantially S-shaped divider wall dividing the
container into two compartments. In these embodiments, each
compartment is in gas communication with one or more vacuum vents
so as to allow the vacuum skin packaging of the products placed in
each compartments. The dividing wall extends from one side wall of
the container to the opposite side wall, or from one shelf to the
opposite shelf depending on the configuration. The height of the
divider wall may be such that it levels with the peripheral flange.
However in the context of the present invention, it is preferred
that the top of the divider wall is lower than the plane of the
peripheral flange so as to allow the products in each compartments
to be individually vacuum skin packaged.
[0107] FIG. 15B shows a variation of the container 101 of FIG. 15A,
a container 201 for vacuum skin packaging a product comprising a
surface 202 for supporting said product and one or more vacuum
vents 203, wherein the one or more vacuum vents are separated from
the supporting surface by one or more separation walls 204. The
container 201 may comprise a divider wall 230 to divide the
container 201 into two compartments. Instead of a rib or shelf 120
extending along the side wall 109, the container 201 comprises two
ribs or protrusions 220 extending from the side wall 209, i.e. one
on each side of the separation wall 204. Preferably, the two
protrusions 220 are separate and leave a gap therebetween so as to
allow the passage of gas, but to prevent hindering of the vacuum
vents 203 by the product.
[0108] FIG. 16 shows a container 301 for vacuum skin packaging a
product comprising a surface 202 for supporting said product and
one or more vacuum vents 303, wherein the one or more vacuum vents
are separated from the supporting surface by one or more separation
walls 304. This container 301 differs from the preceding
embodiments in that the vacuum vents 303 are positioned outside the
side walls 309 of the container 301. In this embodiment, the
container 301 comprises a first peripheral flange 311 extending
around the mouth of the container 301 and a second peripheral
flange 340 extending outwardly from the side walls 309 of the
container 301. The height of the second peripheral flange 340 on
the side wall 309 is such that the vacuum vents 304 formed therein
are substantially in the plane extending from the supporting
surface 302. A compartment or well 306 is positioned, for example
at each corner of the container 301, and a vacuum vent 304 can be
formed, punched or perforated in each compartment or well 6
(preferably, in the base thereof).
[0109] FIG. 17 shows a container 401 for vacuum skin packaging a
product comprising a surface 402 for supporting said product and
one or more vacuum vents 403, wherein the one or more vacuum vents
are separated from the supporting surface by one or more separation
walls 404. This container 401 differs from the preceding
embodiments in that the vacuum vents 403 are positioned on the
divider wall 430. More particularly, the container 401 comprises a
recess 431 extending substantially along the upper surface of the
divider wall 430. The recess 431 is separated from the supporting
surface of the container 401 by one or more separation walls 404,
formed on either side of the recess 431 so as to partially or
completely surround the recess 431. The vacuum vents 403 are formed
along said recess 431. In this embodiment, it is preferred that the
upper surface of the divider wall 430 is below the plane of the
peripheral flange 411 surrounding the mouth of the container 401 so
as to allow efficient evacuation of the atmosphere within the
container 401.
[0110] FIG. 18 shows a container 501 for vacuum skin packaging a
product comprising a surface 502 for supporting said product and
one or more vacuum vents 503, wherein the one or more vacuum vents
are separated from the supporting surface by one or more separation
walls 504. This container 501 differs from the preceding
embodiments in that the vacuum vents 503 are formed on columns 540
extending from the supporting surface 502. Preferably, the
container 501 comprises one or more columns 540 extending from its
supporting surface 502. Where the supporting surface 502 is divided
into two or more compartments, for example by a divider wall 530,
each compartment comprises at least one column 540. In this
embodiment, the column 540 is substantially cylindrical but may
have alternative shapes. One or more separating walls 504 extend
(in use, vertically) from the upper surface of said column 540 so
as to partially or completely surround a vacuum vent 503 formed in
the upper surface of said column 540. In this embodiment, it is
preferred that the upper surface of the columns 530 is below the
plane of the peripheral flange 511 so as to allow efficient
evacuation of the atmosphere within the container 501.
[0111] FIG. 19 shows a container 601 for vacuum skin packaging a
product comprising a surface 602 for supporting said product and
one or more vacuum vents 603, wherein the one or more vacuum vents
are separated from the supporting surface by one or more separation
walls 604. The container 601 may or may comprise a divider wall 630
for dividing the container 601 into two compartments. In this
embodiment, the vacuum vents 603 are formed in the plane extending
from the supporting surface 602, but separated from said supporting
surface by one or more separation walls 604. The container 601 may
also comprise one or more ribs or protrusions 620 extending from
the side wall 609 of the container 601 and adjacent each vacuum
vent 603 (preferably on either side thereof) so as to prevent the
product from hindering the vacuum vent 603.
[0112] Thus, from the above description, it can be seen that the
present invention provides a container having advantages including
minimising and/or preventing the leakage of juice from a
moisture-containing product during the air evacuation step and
accelerating the vacuum sealing step without compromising the
homogeneity, i.e. the quality, of the seal. The container according
to the present invention thus prolongs the shelf-life of the
contained product.
* * * * *