U.S. patent application number 10/370451 was filed with the patent office on 2003-11-27 for bag for vacuum packaging.
Invention is credited to Salvaro, Marziano.
Application Number | 20030219177 10/370451 |
Document ID | / |
Family ID | 11462184 |
Filed Date | 2003-11-27 |
United States Patent
Application |
20030219177 |
Kind Code |
A1 |
Salvaro, Marziano |
November 27, 2003 |
Bag for vacuum packaging
Abstract
A bag for vacuum packaging, comprising an inner layer, made of
sealable material, and an outer layer that is substantially
impermeable to gases, and at least one sheet element, which is
positioned at least partially proximate to the opening of the bag
so as to keep at least one portion of the inner layer spaced from
at least one portion of at least one face of the at least one sheet
element, in order to form air suction channels.
Inventors: |
Salvaro, Marziano; (Negrar,
IT) |
Correspondence
Address: |
MODIANO & ASSOCIATI
Via Meravigli, 16
MILANO
20123
IT
|
Family ID: |
11462184 |
Appl. No.: |
10/370451 |
Filed: |
February 24, 2003 |
Current U.S.
Class: |
383/101 |
Current CPC
Class: |
B65D 81/2023 20130101;
B65D 81/2038 20130101 |
Class at
Publication: |
383/101 |
International
Class: |
B65D 033/01 |
Foreign Application Data
Date |
Code |
Application Number |
May 24, 2002 |
IT |
VR2002A000059 |
Claims
What is claimed is:
1. A bag for vacuum packaging, comprising: an opening; an inner
layer made of sealable material; an outer layer that is
substantially impermeable to gases; air suction channels; and at
least one sheet element, which is positioned at least partially
proximate to the opening of said bag so as to keep at least one
portion of said inner layer spaced from at least one portion of at
least one face of said at least one sheet element in order to form
said air suction channels.
2. The bag for vacuum packaging of claim 1, wherein said sheet
element is arranged at the opening of the bag so as to keep at
least one portion of both faces of the sheet element spaced from a
respective portion of said inner layer.
3. The bag for vacuum packaging of claim 2, wherein said at least
one sheet element comprises any of a plurality of protrusions and
convexities on said at least one portion of said at least one face
thereof.
4. The bag for vacuum packaging of claim 2, wherein said at least
one sheet element has a substantially undulated structure.
5. The bag of claim 1, comprising a first wall and a second wall,
including each at least one inner layer made of sealable material,
and at least one outer layer which is arranged outside said at
least one inner layer, said outer layer being connected to said
inner layer and being made of a material that is substantially
impermeable to gases, said first and second walls being connected
at a substantially perimetric portion thereof, said at least one
sheet element being interposed between said first and second
walls.
6. The bag according of claim 1, wherein said at least one sheet
element comprises a film made of sealable material.
7. The bag of claim 6, wherein said at least one sheet element is
fixed to said inner layer at least at a region that is proximate to
the opening of said bag.
8. The bag of claim 7, wherein said at least one sheet element is
fixed to said inner layer by means of a food-safe adhesive.
9. The bag of claim 7, wherein said at least one sheet element has
a plurality of micro-openings.
10. The bag of claim 9, wherein each one of said plurality of
micro-openings is conical.
11. The bag of claim 6, wherein said sealable material is selected
from a group comprising polypropylene, polythene and
polyethylene.
12. The bag of claim 11, wherein said substantially gas-impermeable
material is selected from a group comprising polyester and
polyamide.
13. A tubular element for obtaining a vacuum packing bag, having
the features set forth in claim 1.
14. The tubular element of claim 13, wherein the outer and inner
layers form respective first and second bag walls, said bag walls
being constituted, respectively, by a first and a second flat
element, said flat elements being substantially rectangular and
joined at opposite long sides thereof, said sheet element being
interposed between said two flat elements.
15. The tubular element of claim 14, being constituted by at least
one segment of preset length cut from a tubular length of material,
said segment being sealed at one end thereof in order to provide
said bag with said opening.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a bag for vacuum packaging,
particularly suitable for the food sector.
[0002] Vacuum packaging machines of the so-called "external
suction" type are commercially available which in a first step
produce vacuum inside bags, generally made of synthetic material,
by aspirating the air from the inside of the bags, and in a second
step seal the opening of the bags so as to prevent the subsequent
return of air into the bags.
[0003] Usually, bags used in this sector are constituted by two
substantially rectangular walls that are heat-sealed at three of
their four sides.
[0004] Each wall is constituted by two layers, an inner one made of
sealable material generally suitable for food use, such as
polyethylene, polythene or polypropylene, and an outer one, which
is substantially impermeable to gases: some polymers, including
polyester or polyamide, for example, have been found to be suitable
for the purpose. The two layers, the inner one and the outer one,
are connected one another.
[0005] When using bags of this type with external suction devices,
it has been found that long before all the air that they contain
has been aspirated, the walls of the bag make contact with each
other, adhering to each other proximate to the nozzle, or more
generally at the suction region, of the suction pump; accordingly,
the pump is prevented from extracting all the air contained in the
bags.
[0006] Various solutions have been proposed in order to solve this
problem. In one of these solutions, the user deforms the walls of
the bag proximate to the suction nozzle (by forming folds, for
example) in order to form suction channels.
[0007] It is evident that although this solution allows to reduce
the drawback noted above it is very awkward and moreover does not
give assurance of fully evacuating the air from the inside of the
bag.
[0008] A different attempt to solve the problem described above
(reference should be made in this regard to U.S. Pat. No.
2,778,173, U.S. Pat. No. Re. 34,928 and EP 0 216 327 B1) consists
in acting on the shape of at least one of the inner layers by
adding or removing material, so as to obtain protrusions and/or
recesses capable of making evacuation channels available to the
air.
[0009] In this manner, even if the two walls adhere one another,
the presence of such channels ensures that the pump can fully
aspirate the air from the inside of the bag.
[0010] Even this solution, though providing a considerable
improvement of the suction conditions, is not devoid of
drawbacks.
[0011] First of all, the protrusions, which are formed at at least
one of the inner layers, allow to obtain suction channels but do
not allow to perform, at the end of the suction step, optimum
sealing of the two walls: accordingly, the seal produced is often
not efficient.
[0012] Furthermore, if only the face of the inner layer that is
directed inward is deformed, leaving flat the face meant to couple
to the outer layer, material (polyethylene in particular) is wasted
without thereby obtaining any advantage in terms of gas tightness
(tightness is ensured by the thickness of the outer layer) or in
terms of sealability.
[0013] On the other hand, the provision of incisions on the inner
surface of the bag to form said channels can reduce the thickness
of the layer made of a material that is impermeable to gases, with
a consequent decrease of its tightness.
[0014] If instead one uses an inner layer that is deformed so as to
have, for example, protrusions at the face meant to be directed
inward and respective recesses on the opposite face, air bubbles
form between said inner layer and the outer layer and, since the
inner layer is made of a material that is permeable to gases,
migrate over i time into the bag, consequently compromising its
tightness.
SUMMARY OF THE INVENTION
[0015] The aim of the present invention is to eliminate or at least
drastically reduce the drawbacks noted above in known types of
vacuum packaging bag.
[0016] Within this aim, an object of the present invention is to
provide a bag, particularly for vacuum packaging,, that ensures
total evacuation of the air.
[0017] Another object of the present invention is to provide a bag
for vacuum packaging that is capable of ensuring perfect
sealability, so as to ensure its perfect tightness over time.
[0018] Another object of the invention is to provide a bag for
vacuum packaging that is capable of ensuring, over time, a gas
tightness and particularly a tightness against the inflow of air
that is comparable to that of bags used with chamber-type
machines.
[0019] Another object of the present invention is to provide a bag
for vacuum packaging that allows to extract air at a substantially
faster rate than the bags currently in use.
[0020] Another object of the present invention is to provide a bag
for vacuum packaging that has a low production cost, in order to be
advantageous also from the economical standpoint.
[0021] This aim and these and other objects which will become
better apparent hereinafter are achieved by a bag for vacuum
packaging, comprising an inner surface made of sealable material
and an outer surface that is substantially impermeable to gases
characterized in that it comprises at least one inner sheet
element, which is positioned at least partially proximate to the
opening of said bag and is adapted to keep at least one portion of
said inner surface spaced from at least one portion of at least one
face of said at least one sheet element in order to form air
suction channels.
[0022] Advantageously, said sheet, element is adapted to keep at
least one portion of both of its faces spaced from a respective
portion of said inner surface.
[0023] According to another aspect, the present invention provides
a tubular element for providing said bag, characterized in that it
comprises an inner surface made of sealable material and an outer
surface that is substantially impermeable to gases and in that it
comprises internally at least one sheet element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Further characteristics and advantages of the invention will
become better apparent from the description of a preferred but not
exclusive embodiment of a bag for vacuum packaging according to the
invention, illustrated only by way of non-limitative example in the
accompanying drawings, wherein:
[0025] FIG. 1 is a perspective view of a bag for vacuum packaging
according to the invention; and
[0026] FIG. 2 is a partial sectional perspective view of a wall of
the bag, taken along the line II-II of FIG. 1;
[0027] FIG. 3 is an enlarged-scale partial sectional perspective
view of a sheet element, taken along the line III-III of FIG.
1;
[0028] FIG. 4 is a schematic view of an apparatus adapted to
provide a tubular element;
[0029] FIG. 5 is a top view of the apparatus of FIG. 4;
[0030] FIG. 6 is a schematic view of a device for providing the bag
according to the invention;
[0031] FIG. 7 is a view of a bag according to the invention that
has a reduced length; and
[0032] FIG. 8 is a view of a bag according to the invention that is
longer than the bag of FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] With reference to the figures, a bag for vacuum packaging
according to the invention, generally designated by the reference
numeral 1, can be constituted for example by a first wall 2 and by
a second wall 3, which substantially have the same shape (in the
drawings, the first wall 2 and the second wall 3 are substantially
rectangular but can have other shapes as well) and are generally
heat-sealed to each other along three sides, so as to form a
receptacle, which can be accessed through an opening 1a and is
meant to contain, for example, food products to be preserved in
vacuum.
[0034] As an alternative, the bag 1 can be constituted by a
monolithic tubular body, not shown in the figures, which is closed
at one end, for example by heat-sealing, in order to form the
bottom of the bag 1, and is open at the other end, so as to form
the opening 1a.
[0035] The opening 1a is designed to engage the suction region
(nozzle or, optionally, chamber), not shown in the figures, of a
pump associated with a vacuum packaging machine of the external
suction type.
[0036] The first wall 2 and the second wall 3 have respectively an
inner sealable surface or layer, which allows to close hermetically
the bag 1 once the air has been aspirated from its interior, and an
outer surface or layer that is substantially impermeable to gases
and prevents the air from entering the bag 1 and compromising the
preservation of any food contained therein.
[0037] In particular, the first wall 2 and the second wall 3 are
structured so as to have an inner layer 4, made of sealable
material such as for example polypropylene or polythene or
polyethylene, which also have the characteristic of being suitable
for food use, and an outer layer 5 made of a material that is
substantially impermeable to gases.
[0038] Polymeric materials, such as polyester, polyamide or
Nylon.RTM., have been found to be particularly suitable to provide
said outer layer 5.
[0039] The inner layer 4 and the outer layer 5 are connected and
perfectly coupled, so that they do not trap between them bubbles or
pockets of air, which over time might migrate through the inner
layer 4 and reach the inside of the bag 1.
[0040] According to the invention, the bag 1 is provided internally
with at least one sheet element 6, which is arranged at least
partially proximate to the opening 1a.
[0041] Also according to the invention, said sheet element 6 is
adapted to keep at least one portion of the inner surface of the
bag 1 spaced from at least one of its faces 6a, or from part of its
faces 6a, so as to form air suction channels 8.
[0042] More particularly, as shown in the drawings, the sheet
element 6 can be structured so as to keep both the first wall 2 and
the second wall 3 spaced from each other and from the sheet element
6 itself, so as to form said suction channels 8 between said sheet
element 6 and the first wall 2 and between said sheet element and
the second wall 3.
[0043] Advantageously, the sheet element 6 is capable of preventing
the mutual collapse of the first wall 2 and of the second wall 3 by
providing protrusions, such as for example, ribs or studs and/or
recesses, such as for example slots or cavities, on a portion, or
on the entirety, of one or both of its faces 6a.
[0044] As an alternative, as shown more clearly in FIG. 1, the
sheet element 6 has an undulated structure, with an alternation of
peaks or convexities and troughs or concavities arranged
transversely to the opening 1a.
[0045] The peaks and troughs, as shown in FIG. 1, may be replaced
by corresponding ribs or studs and recesses or slots or cavities in
the embodiments mentioned above.
[0046] Conveniently, the sheet element 6, in addition to being
rigidly coupled laterally to the edges 1b of the bag 1, has a
plurality of micro-openings 7, which are designed to increase
suction by connecting the suction channels delimited by the first
wall 2 and by the sheet element 6 to the channels delimited by the
second wall 3 and by said sheet element 6 and vice versa.
[0047] In the illustrated embodiment, in order to facilitate the
rapid and easy outflow of the air, each one of said micro-openings
7 is frustum-shaped, but nothing prevents them from being
cylindrical.
[0048] The sheet element 6 can also be arranged along at least half
of the bag 1, so as to also affect part of the region occupied by
the products introduced therein.
[0049] This, if the separation action applied by the sheet element
6 fails, prevents the mutual adhesion of the first wall 2 and the
second wall 3 in the region between the suction nozzle and the
product to be packaged, which would prevent complete evacuation of
the air.
[0050] Preferably, the region of the sheet element 6 that is
substantially proximate to the opening 1a and is arranged along the
edge of said opening is fixed to the inner surface of the bag 1, by
heat-sealing or food-safe adhesive, so that the edge of the sheet
element 6 that is proximate to the opening 1a does not hinder the
insertion of the products to be packaged and preserved inside the
bag 1.
[0051] Moreover, one face 6a of the element 6 can be coupled,
preferably by means of a food-safe adhesive and/or by heat sealing,
to the inner surface of the bag 1 along its entire extension or
optionally on part thereof and particularly at a substantially
median region thereof, which lies substantially longitudinally with
respect to the bag 1, starting from the region proximate to the
opening 1a and up to a region that lies substantially opposite said
region.
[0052] Operation of the invention is rather evident from the above
description: once the product to be packaged has been inserted in
the bag 1, the opening 1a is coupled to an external suction device,
which by way of said suction nozzle or chamber extracts the air
contained inside the bag.
[0053] Full extraction of the air is ensured by the fact that
notwithstanding the tendency of the first wall 2 and of the second
wall 3 to collapse during aspiration, the sheet element ensures
that suction channels remain open through which the air can flow
out, arriving even from the furthest regions, such as for example
the bottom of the bag 1.
[0054] The presence of the micro-openings 7 allows, if some
channels are blocked for any reason, to bypass said channels,
providing the extracted air with a path to access other
channels.
[0055] Advantageously, the user can obtain the bag 1 starting from
a tubular element (possibly available in rolls), formed
monolithically or constituted by a pair of flat elements that are
substantially rectangular and joined at the two opposite long
sides.
[0056] According to the invention, a sheet element 6 is arranged
and anchored, in the manner described above, inside said tubular
element.
[0057] Conveniently, and in the same manner described for the first
wall 2 and the second wall 3, the tubular element has a sealable
inner surface and an outer surface that is substantially
impermeable to gases.
[0058] By cutting, performed by means of any bladed instrument,
such as for example scissors, the user can obtain at least one
piece of preset length of the tubular element.
[0059] Said piece can be closed and sealed at one end, by using
suitable heat-sealing means, so as to obtain the bag 1 according to
the invention having the length dimensions required-by the
user.
[0060] Therefore, users, according to the requirements or the
dimensions of the food to be preserved, can easily have available a
short bag 1 or a long bag 1, as shown respectively in FIGS. 7 and
8.
[0061] With particular reference to FIGS. 4, 5 and 6, a preferred
method of manufacturing the bag 1 according to the invention and a
suitable apparatus for carrying out the method are described
briefly and merely by way of example.
[0062] A first continuous lamina 10 and a second continuous lamina
11, each provided with a face made of sealable material and another
face made of a material that is substantially impermeable to gases,
are mutually coupled on the side of the respective sealable face,
with the interposition of a third continuous lamina 13, which is
meant to constitute the sheet element 6, by means of a pair of
coupling rollers 12.
[0063] Downstream of the set of coupling rollers 12, two opposite
heat-sealing rollers heat-seal the first and second laminas at
their lateral edges, so as to form in practice said tubular element
constituted by two flat elements, which is then gathered in a roll
16 with the possible aid of conveyor rollers 15.
[0064] The resulting tubular element can subsequently feed a device
17 for mass-producing the bags 1 or can be used directly by the
user in the manners specified above.
[0065] If the device 17 is used, the roll 16 is unwound and the
tubular element is made to advance in the direction indicated by
the arrow 100 intermittently by traction rollers 18 toward a feeder
roller 19, which is arranged opposite a supporting surface 20.
[0066] Said feeder roller 19 is designed to feed the tubular
element to cutting and heat-sealing means 21, which are provided
with a blade 22 that lies transversely to the tubular element and
can move alternately toward and away from it, so as to cut it and
obtain therefrom a piece of preset length.
[0067] Downstream of the blade 22, the cutting and heat-sealing
means 21 further have a heat-sealing bar 23, which also lies
transversely to the tubular element and can move alternately in the
same manner as, and optionally in step with, the blade 22.
[0068] The heat-sealing bar 23 is meant to seal one end of the
piece of tubular element obtained by way of the action of the blade
22 and thus complete the forming of the bag 1.
[0069] The bag 1, once formed, is finally removed from the cutting
and heat-sealing means 21 by conveyor means 24, for example of the
belt type.
[0070] In practice it has been found that the invention has
achieved the intended aim and objects.
[0071] As clearly shown by the description given above, in a bag 1
according to the invention both the first wall 2 and the second
wall 3 are substantially smooth, have a constant thickness and are
therefore capable of being produced by way of a process of
extrusion of the layer of sealable material 4 and of the layer of
substantially gas-impermeable material 5.
[0072] This ensures not only optimum sealability but also, at the
same time, perfect gas-tightness.
[0073] The invention thus conceived is susceptible of numerous
modifications and variations, all of which are within the scope of
the appended claims.
[0074] The bag, according to the invention may, for example, be
used in the medical or chemical field, for packing compositions
which require special preservation conditions.
[0075] In practice, the materials used, as well as the dimensions
and shapes, may be any according to requirements.
[0076] The disclosures in Italian Patent Application No.
VR2002A000059 from which this application claims priority are
incorporated herein by reference.
* * * * *