TECHNICAL FIELD
[0001] The present invention relates to the field of pressure relief one-way valve for hermetic
containers, for example, for hermetic food containers.
PRIOR ART
[0002] Several types of pressure relief one-way valves are known from the prior art. Recently,
the market for these valves has considerably increased, to the point of requesting
an annual production of a few billion units. The high request of the market, which
is still growing at the moment, requires the quick and low cost production of such
valves.
[0003] The valves known from the state of the art normally have rubber membranes, held in
place in the body of the valve by a layer of silicon oil, on the sealing seat of the
membrane. When the high pressure gas, produced by the substance inside the hermetic
container, needs to come out of the container, it pushes the rubber membrane which
separates from its seat, allowing the gas to escape, and then returns to its place.
[0005] The type of valve described above can present inconveniences. In particular, the
closing and opening of the valves of the known type from the state of the art are
often defective. More particularly, some of the known valves do not properly reclose
after the pressure relief operation. In this way, the air can enter inside the container,
compromising the maintenance of the quality of the product inside same. Alternatively,
some of the known valves may not open correctly, preventing the pressure relief and
the dangerous increase of the pressure inside the container.
[0006] Since in some known valves from the state of the art the rubber membrane is held
in place only by the layer of silicone oil, if the air passage is too violent, it
may completely detach the membrane from the body valve. If this happens, the membrane
stops its one-way function because, when the membrane is detached, air can enter inside
the container.
[0007] Moreover, the rubber membrane has to be transported from the place where it is produced
to the place in which it has to be assembled to the other parts of the valve.
[0008] This clearly increases, in a significant way, the time and the costs of the valve
production process.
[0009] It is, therefore, an aim of the present invention to solve the above-cited problems.
[0010] More specifically, it is an aim of the present invention to provide valves for hermetic
containers having optimum opening and closing functions.
[0011] It is a further aim of the present invention to provide economic and easy to assemble
valves for hermetic containers.
SUMMARY
[0012] The present invention is based on the idea of providing a pressure relief one-way
valve comprising a valve body, a valve cap and a membrane, in which the valve cap
comprises at least a rib which holds the valve membrane in its sealing seat in the
valve body and which allows it to lift only on one side of a fixed length. In particular,
according to the present invention, the membrane has only one portion which lifts
up due to the effect of the pressure of the gas contained inside the packaging on
which the valve is applied. The free to lift portion has, in section, a fixed length.
In this way, the valve membrane is firmly held in position by the rib. The probability
that the membrane irreparably exits from its seat is significantly reduced. Furthermore,
since the membrane is free to lift only on one side, the opening of the valve is optimized.
[0013] The valve according to the present invention can be used for hermetic containers
or packages containing food, for example, roasted coffee.
[0014] According to the present invention a pressure relief one-way valve for hermetic packing
is provided, the valve comprising a valve body, a valve cap and a valve membrane,
wherein the valve body comprises a base comprising a sealing seat for the valve membrane
and one or more holes adapted to let the gas flow through the valve, wherein the valve
cap is housed in said valve body and comprises a pressure relief opening wherein said
valve membrane is flexible and is placed between the valve body and the valve cap
in the sealing seat. The pressure relief one-way valve is such that the valve cap
comprises a first rib placed laterally with respect to the pressure relief opening
so as to keep the valve membrane in said sealing seat so that the valve membrane can
lift, during the pressure relief operation, only on one side, and so that the free
to lift portion of said valve membrane has a length equal to or less than the distance
between the first rib and the non-fixed end of the valve membrane. In this way, the
valve membrane, kept in its sealing seat by the first rib, never completely moves
far from it, ensuring the one-way function of the valve. In addition, maximizing the
fixed length of the free to lift portion of the valve membrane, the maximum possible
opening degree for the valve is maximized. Moreover, the configuration of the valve
cap according to the present invention allows working with valve membranes, particularly
thin, that can for example be advantageously obtained by cutting them from a film.
Even if the membrane is very thin, the configuration of the valve cap according to
the present invention ensures the tightness of the valve. In particular, the valve
membrane is efficiently held in its sealing seat even after several opening and closing
operations of the valve.
[0015] According to the present invention, the valve cap comprises a second rib, placed
on the same side of the valve cap with respect to the pressure relief opening, on
which the first rib is placed, so that the portion of the valve membrane free to lift
during the pressure relief operation has a fixed length smaller than the distance
between the first rib and the non-fixed end of the valve membrane. The second rib
is preferably placed between the first rib and the tangent to the pressure relief
opening of the valve cap parallel to the first rib. In this way, the valve membrane
is not only held in its sealing seat by the first and second rib, so that it never
completely move away from it, ensuring the one-way function of the valve, but it ensures
that the opening of the valve, during the pressure relief operation, is smaller and
therefore faster. The opening pressure limit of the valve is, therefore, higher and
the closing of the same is quicker. The position of the second rib, more or less close
to the first rib, determining the length of the free to lift portion of the valve
membrane, affects the opening pressure limit of the valve. Moreover, the configuration
of the valve cap according to this embodiment of the present invention allows working
with particularly thin valve membranes, which can be for example advantageously obtained
by cutting them from a thin film. Even if the membrane is particularly thin, the configuration
of the valve cap according to this embodiment of the present invention ensures the
tightness of the valve. In particular, the valve membrane is efficiently held in the
sealing seat even after several opening and closing operations of the valve.
[0016] According to a further embodiment of the present invention, the fixed length of the
free to lift portion of the membrane is equal to at least half the maximum width of
the membrane, preferably at least two-thirds or four fifths of the maximum width of
the valve membrane. According to a further embodiment of the present invention the
pressure relief opening is at the centre of the valve cap.
[0017] According to a further embodiment of the present invention, the valve membrane has
a thickness comprised between 10 micron and 100 micron, preferably between 40 micron
and 60 micron, preferably equal to 50 micron. These thicknesses improve the flexibility
and elasticity properties of the membrane, optimizing the functionality of the valve.
The membrane can have a diameter of about 9 mm.
[0018] According to a further embodiment of the present invention, the valve cap further
comprises a projecting element adapted to limit the bending of the membrane during
the pressure relief operation. In this way, the valve membrane never completely lies
on the valve cap, ensuring that air does not find barriers in its way out of the valve
during the pressure relief.
[0019] According to a further embodiment of the present invention, the upper surface of
the valve cap is coplanar with the upper surface of the valve body. The valve is therefore
of the flat type.
[0020] According to a further embodiment of the present invention, the upper surface of
the valve cap is on a lower level with respect to the upper surface of the valve body.
[0021] According to a further embodiment of the present invention, the valve cap is two-faced,
namely it is made in such a way that its functionality is identical independently
of the orientation with which it can be inserted into the valve body. In this way,
the valve cap does not need to be oriented according to a preferred orientation in
order to be inserted in the valve body. This, of course, significantly simplifies
the assembly operations of the valve.
[0022] According to a further embodiment of the present invention, the valve cap is symmetrical
with respect to a plane parallel to the base of the valve body and passing through
the centre of the valve cap so that the valve cap does not have to be oriented according
to a preferred orientation in order to be placed into the valve body. This simplifies
and speeds up the assembly operations of the valve. The valve cap, in fact, does not
need to be pre-oriented, before being placed into the valve body.
[0023] According to a further embodiment of the present invention, the sealing seat is covered
with a viscous layer, for example, made of silicone oil, so as to improve the tightness
of the valve membrane. In this way, the valve membrane is kept in its sealing seat
not only by the first and/or the second rib, but also by the viscous layer which ensures
that the membrane closes the one or more holes on the base of the valve body, when
the valve is not working.
[0024] According to a further embodiment of the present invention the pressure relief one-way
valve further comprises a filtering element adapted to filter the gas that flows through
the one or more holes of the valve body. In this way, while the air molecules are
free to pass through the valve, and to exit, therefore, from the hermetic container,
the aroma molecules can be kept inside the container by the filtering element. This
allows optimizing the organoleptic properties of the product contained in the container
to which the valve is applied.
[0025] According to a further embodiment of the present invention the filtering element
comprises a nonwoven polyester, for example, SMASH™. SMASH™ is a particular polyester
made from a nonwoven fabric made of a continuous fabric. SMASH™ is a thermoplastic
material, it is easily deformable at high temperatures and can be hot pressed. Moreover,
it resists very well to hot water and can be steadily extracted. This material is
cheap and it is particularly suitable for conveniently filtering the gas inside the
hermetic container.
[0026] According to a further embodiment of the present invention, the valve body and/or
the valve cap are made of biodegradable material, for example oxo-biodegradable material.
This has the known advantages for the environment.
[0027] According to a further embodiment of the present invention the valve membrane comprises
a non-biodegradable material, for example PET.
[0028] According to a further embodiment of the present invention the weight of the valve
membrane is equal to 0.1% or less of the total weight of the valve, for example equal
to 0.06% of the total weight of the valve. In this way, even if the valve membrane
is not made of biodegradable material, the valve can be considered to be biodegradable,
because the percentage of non-biodegradable material with respect to the total amount
of material of the valve falls within the limits set by the current regulations. For
example, the valve membrane can have a weight of about 0.0006 g and the valve may
have a total weight of about 1 g.
[0029] According to a further embodiment of the present invention the materials of which
the valve is made can be enriched with additives. This allows simplifying the operations
of quality control of the valve during the production process since the additives
allows an easier identification of defects in the structure of the valve.
[0030] According to a further embodiment of the present invention, an hermetic container
is provided, preferably a container for food, to which a valve according to the present
invention is applied. The hermetic container can be, for example, a package for coffee
beans.
[0031] According to the present invention a method is provided for manufacturing a pressure
relief one-way valve for hermetic packaging comprising a valve body, a valve cap and
a valve membrane, in which the valve body comprises a base comprising a sealing seat
for the valve membrane and one or more holes suitable for letting the gas go through
the valve, in which the valve cap is seated in the valve body and comprises a pressure
relief opening and in which the valve membrane is flexible and placed between the
valve body and the valve cap in the sealing seat, in which the method comprises the
following step: the formation in the valve cap of a first rib laterally placed with
respect to the pressure relief opening so as to keep the valve membrane locked in
its sealing seat so that the valve membrane is free to lift, during the pressure relief
operation, only on one side and so that the free to lift portion of the valve membrane
has a length equal to or less than the distance between the first rib and the fixed
end of the valve membrane.
[0032] According to the present invention a method is provided for manufacturing a pressure
relief one-way valve for hermetic packaging comprising a valve body, a valve cap and
a valve membrane, in which the valve body comprises a base comprising a sealing seat
for the valve membrane and one or more holes suitable for letting the gas pass through
the valve, in which the valve cap is seated in the body valve and comprises a pressure
relief hole and in which the valve membrane is flexible and it is placed between the
valve body and the valve cap in the sealing seat, in which the method comprises the
following step: the formation in the valve cap of a first rib, placed laterally with
respect to the pressure relief opening so as to keep the valve membrane in the sealing
seat so that the valve membrane can lift, during the pressure relief operation, only
on one side and so that the free to lift portion of the valve membrane has a length
equal to or less than the distance between the first rib and the non-fixed end of
the valve membrane.
[0033] According to the present invention a method is provided further comprising the following
step: the formation in the valve cap of a second rib placed on the same side of the
valve cap with respect to the pressure relief opening on which the first rib is placed,
so that the portion of the valve membrane free to lift during the pressure relief
operation has a fixed length less than the distance between the first rib and the
non-fixed end of the valve membrane.
[0034] According to a further embodiment of the present invention a method is provided for
the production of a pressure relief one-way valve, in which the valve membrane is
cut from a film and placed in its sealing seat of the valve body in a single operation.
In this way, a fast and cheap method is provided for the production of the valve.
[0035] According to a further embodiment of the present invention a method is provided for
the production of a pressure relief one-way valve, in which the valve body and/or
the valve cap are injection moulded.
BRIEF DESCRIPTION OF THE FIGURES
[0036] The present invention will be described with reference to the attached Figures in
which identical numbers and/or reference signs indicate the same parts and/or similar
parts and/or corresponding parts of the system.
Fig. 1A schematically shows a pressure relief one-way valve for hermetic packaging,
according to an embodiment, not claimed, seen in vertical section along one of its
diameters.
Fig. 1B schematically shows the pressure relief one-way valve shown in Fig. 1A, seen
in vertical section along one of its diameters and applied to a hermetic food container.
Fig. 1C schematically shows the pressure relief one-way valve shown in Fig. 1A, seen
from above.
Fig. 1D schematically shows a 3D view of the pressure relief one-way valve shown in
Fig. 1A, positioned so as to show the base of the valve body.
Fig. 1E schematically shows a 3D view of the pressure relief one-way valve shown in
Fig. 1A, positioned so as to show the valve cap.
Fig. 1F schematically shows a zoom of the region of the pressure relief one-way valve
shown in Fig. 1A, in which the valve cap wedges into the valve body.
Fig. 2A schematically shows a pressure relief one-way valve for hermetic packaging,
according to the present invention, seen in vertical section along one of its diameters.
Fig. 2B schematically shows the pressure relief one-way valve shown in Fig. 2A, seen
in vertical section along one of its diameters and applied to a hermetic food container.
Fig. 2C schematically shows the pressure relief one-way valve shown in Fig. 2A, seen
from above.
Fig. 2D schematically shows a 3D view of the pressure relief one-way valve shown in
Fig. 2A, positioned so as to show the base of the valve body.
Fig. 2E schematically shows a 3D view of the pressure relief one-way valve shown in
Fig. 2A, positioned so as to show the valve cap.
Fig. 3A schematically shows a pressure relief one-way valve for hermetic packaging,
according to a further embodiment, not claimed, seen in vertical section along one
of its diameters.
Fig. 3B schematically shows the pressure relief one-way valve shown in Fig. 3A, seen
in vertical section along one of its diameters and applied to a hermetic food container.
Fig. 4A schematically shows a pressure relief one-way valve for hermetic packaging,
according to a further embodiment of the present invention, seen in vertical section
along one of its diameters.
Fig. 4B schematically shows the pressure relief one-way valve shown in Fig. 4A, seen
in section along one of its diameters and applied to a hermetic food container.
Fig. 5 schematically shows the valve membrane production system for a pressure relief
one-way valve according to an embodiment of the present invention.
DETAILED DESCRIPTION
[0037] In the following, the present invention will be described with reference to particular
embodiments, as shown in the attached Figures. However, the present invention is not
restricted to the particular embodiments described in the following detailed description
and as shown in the Figures, rather the described embodiments merely show several
aspects of the present invention whose scope is defined by the claims. Further modifications
and variations of the present invention will be clear for the person skilled in the
art.
[0038] Figure 1A schematically shows a pressure relief one-way valve for hermetic packaging,
not claimed.
[0039] The hermetic container to which the valve can be applied can be a food container,
for example, a package for roasted coffee.
[0040] The valve comprises three main elements: a valve body A, a valve cap B and a valve
membrane C. The valve body A comprises a base comprising a sealing seat 11 for the
valve membrane C and one or more holes 6 suitable for letting the gas coming from
the container go out through the valve 1. The valve body A further comprises a seat
for the valve cap B. The valve cap B is, in fact, placed in the valve body A. The
sealing seat 11 is formed at the base of the seat for the valve cap B. The valve cap
B comprises a pressure relief opening 4. The pressure relief opening 4 of the valve
cap B can advantageously be placed at the centre of the valve cap B, as shown in Figure
1A. The valve membrane C is flexible and it is placed between the valve body A and
the valve cap B in the sealing seat 11.
[0041] The sealing seat 11 can comprise a cavity formed in the base of the valve body A
and having dimensions corresponding to the dimensions of the valve membrane C. In
particular, the depth of the cavity can be equal to the thickness of the membrane
C. The sealing seat can be filled with sealing material 5, for example, silicone oil
so as to maintain the membrane in contact with the valve cap B and so as to keep the
valve membrane in contact with the valve cap B and so as to ensure the valve tightness
when no portion of the valve membrane C is lifted.
[0042] The valve body A may have a frusto-conical shape, open on the wide side and closed
on the opposite side. We will refer to this closed side of the valve body A as the
base 13 of the valve body. The valve body A comprises, moreover, a flat border 10,
protruding from the valve body, from the open side of the cone, toward the outside
of the same, and parallel to the base 13 of the valve body. The border 10 is suitable
for fixing the valve 1 to the hermetic container, to which the valve is applied.
[0043] The valve 1 shown in Figure 1A is an internal valve. The valve 1, in fact, is suitable
to be applied to the hermetic container by fixing the upper surface of the border
10 of the valve body A to the inner surface of the container itself. In Figure 1B,
the valve 1 is shown applied to a hermetic food container. In Fig. 1B, F is the film
of the hermetic container which is fixed to the valve 1. The film F, after the application
of the valve 1 inside the hermetic container, can be pierced by a needle P, in correspondence
of the pressure relief opening 4 of the valve cap B. The hermetic food container,
schematically shown in Fig. 1B, contains coffee beans.
[0044] On the inner surface of the base 13 of the valve body, that is the one facing towards
the inside of the hermetic container when the valve is applied to the same, a filtering
element 7 can advantageously be placed, as for example, a membrane made of filter
paper or made of a nonwoven polyester, for example, SMASH™. SMASH™ is a particular
polyester made of a nonwoven continuous fibre. SMASH™ is a thermoplastic material,
is easily deformed at high temperatures and can be hot moulded. Moreover, it substantially
resists hot water and can be stably extracted. The filtering element can let air molecules
exit from the hermetic container and at the same time secure inside same the aroma
molecules produced by the food contained in it. Moreover, the filtering element 7
can be permeable to gases but impermeable to liquids. In this case, the valve with
a filtering element with such features can advantageously be applied to hermetic containers
which contain liquids which produce gases, after they have been hermetically packaged,
as for example liquid yeast.
[0045] The valve cap B is wedged in the valve body A, as shown in detail in Fig. 1F, where
the wedging zone between the cap B and the valve body A is shown enlarged. It has
to be noted that the side wall of the seat for the cap B of the valve body A is structured
so as to fit together with the side surface of the valve cap B. In particular, the
side wall of the seat A comprises an indentation 14. The side surface of the valve
cap B comprises a protrusion 15. The indentation 14 accommodates the protrusion 15
so as to fix the valve cap B inside of the valve body A. In this way the valve cap
B is stably fixed inside the valve body A.
[0046] The valve cap B can advantageously be two-faced. The valve cap B shown in Figure
1 A is, for example, made so that its functionality is the same independently from
the orientation with which it can be inserted in the valve body A. In this way, the
valve cap B does not need to be oriented according to a preferred orientation in order
to be placed inside the valve body A. Clearly, this substantially simplifies the assembly
process of the valve 1. In a possible embodiment, not shown in the figure, the valve
cap can be made so as to be symmetric with respect to a plane X parallel to the base
of the valve body and passing through the central point of the valve cap O.
[0047] The valve cap B comprises, moreover, the first rib 2 placed laterally with respect
to the pressure relief opening 4 in order to fix the valve membrane C in the sealing
seat 11 so that the valve membrane C is free to lift during the pressure relief operation,
only on one side and so that the free to lift portion of the valve membrane C has
a fixed length L equal to or less than the distance between the first rib 2 and the
fixed end of the valve membrane C. The first rib 2 may extend along the valve cap
C, between two points of its peripheral edge. The fixed length L can be equal to at
least half of the maximum length of the valve membrane. Preferably, the default length
L can be 4/5 (four fifths) of the maximum length of the valve membrane C.
[0048] As shown in Figure 1A, the first rib 2 divides the membrane C in two portions: a
first portion free to lift as an effect of the gas under pressure contained inside
the container on which the valve is applied and a second portion which cannot lift.
The first portion, seen in section, has length L. The first portion is the only portion
of the membrane C that lifts due to the gas under pressure contained in the container
on which the valve is applied.
[0049] The valve cap B comprises, moreover, a protruding element 3, suitable for limiting
the bending of the valve membrane C during the pressure relief operation. The protruding
element 3 avoids that the valve membrane C completely leans on the valve cap B. In
this way, it is efficiently avoided that the lifted portion of the valve membrane
blocks the exit of the gas from the valve. In other words, the protruding element
3 allows forming exit routes for the gas even when the free to lift portion of the
membrane is completely lifted due to the effect of the gas under pressure coming from
the container on which the valve is applied. The protruding element 3 may comprise
a hemisphere or a sphere placed along one of the diameters of the valve cap B. The
protruding element 3 is advantageously placed laterally with respect to the pressure
relief opening 4 of the valve cap B on the side opposite with respect to the one on
which the first rib 2 is formed.
[0050] The upper surface of the valve cap B, facing the outside of the valve 1, is, in the
embodiment shown in Figure 1A, coplanar with the upper surface of the flat border
of the valve body A. The valve 1 is, therefore, of the flat type.
[0051] The valve membrane C is placed between the valve body A and the valve cap B in its
sealing seat 11. The valve membrane C is a flexible membrane, preferably made of plastic
material, for example PET. The valve membrane C may have a thickness comprised between
10 microns and 100 microns. Preferably, the valve membrane C has a thickness comprised
between 40 microns and 60 microns. For example, the thickness may be equal to 50 microns.
[0052] Between the valve body A and the valve membrane C a layer of viscous material 5,
for example silicone oil can be inserted. This layer contributes with the rib 2 to
keep the valve membrane C in the sealing seat 11, when the valve is in a rest position
and allows the valve to close, in a hermetic way, the one or more holes 6 of the valve
body A. In particular, the layer of viscous material 5 allows optimizing the tightness
between the sealing seat 11 and the portion of the membrane C free to lift during
the pressure relief operation.
[0053] In this case, the thin valve membrane C is held in position, not only by the viscous
layer 5 but also by the first rib 2 of the valve cap C. In this way, if during the
operational phase, that is during the pressure relief phase, the passage of air takes
place in a violent way, there is no risk that the valve membrane C completely exits
from its sealing seat 11. The membrane, in fact, never completely leaves its sealing
seat 11, and once the push of the gas exiting from the hermetic container stops, it
closes returning in the sealing seat. On the contrary, in the valves of the type known
from the state of the art, the membrane made of rubber may completely separate from
its seat. Once the membrane is detached, the valve loses its one way functionality
because the holes of the valve body remain open.
[0054] The valve body A and/or the valve cap B of the valve 1 may advantageously be made
of biodegradable material. More in particular, the valve body A, and/or the valve
cap B may be made in an oxo-biodegradable material. Advantageously, both the valve
body A and the valve cap B are made of biodegradable material.
[0055] Examples of biodegradable materials that can be used according to the present invention
are aliphatic polyester, polylactic acid (PLA) and blends of different proportions
of aliphatic polyester and polylactic acid.
[0056] The valve membrane C can have a weight equal to or less than 0.1 % of the total weight
of the valve 1, for example equal to 0.06 %. For this reason, if the valve body A
and the valve cap B valve are made of biodegradable material, the valve 1 can be considered
to be completely biodegradable even if the membrane C is not made of biodegradable
material, for example if it is made of PET.
[0057] Figure 1C schematically shows the valve 1 shown in Figure 1A, seen from above, that
is, so as to show the valve cap B. From this figure it is possible to see the border
10 of the valve body A, which is suitable to seal the hermetic container to the valve
1, the central opening 4 of the valve cap B and the first rib 2, which keeps the membrane
C in place in its sealing seat inside the valve body A. The first rib 2 may extend
along the valve cap B between two points of its peripheral edge.
[0058] The valve 1, according to the embodiment shown in the figure, has a valve body A
having a circular shape. Moreover, also the seat for the valve cap B has a circular
shape. The valve cap B and the valve membrane C are circular. More in particular,
the valve cap B is such that it can be placed in the seat of the valve body A so as
to close the valve 1. The first rib 2 that keeps the valve membrane C in the seat
11 is made along a first chord of the valve cap B so as not cross the pressure relief
opening 4. The first rib 2 extends along the entire length of the first chord.
[0059] Figure 1D schematically shows the valve 1 in 3D placed so as to show the base of
the valve body 13. In this figure the filtering element filter 7 is visible and the
holes 6 on the base of the valve body 13, under the filtering element 7, are shown
with dotted lines. Figure 1E schematically shows valve 1 in 3D placed so as to show
the valve cap. In this image, the flat border 10 of the valve body A, the pressure
relief opening 4 of the valve cap B and the first rib 2 are visible.
[0060] Figures from 2A to 2E correspond to Figures from 1A to 1E, respectively, and show
a pressure relief one-way valve according to the already indicated views. The difference
between the valve shown in Figures from 1A to 1D and the one shown in Figures from
2A to 2E consists in that the valve 1 shown in Figures from 2A to 2E comprises a valve
cap B further comprising a second rib 8. Figure 2B shows the pressure relief valve
shown in Figure 2A applied to a hermetic container containing roasted coffee. The
film F of the hermetic packaging for food, the needle P which is suitable to perforate
the film F in correspondence to the pressure relief opening of the valve cap and the
coffee beans are shown.
[0061] The second rib 8 is placed on the valve cap B on the same side of the first rib 2
with respect to pressure relief opening 4. More in particular, the second rib 8 is
placed between the first rib 2 and the tangent to the pressure relief opening 4 of
the valve cap B parallel to the first rib 2. The second rib 8 further keeps the valve
membrane C blocked in its sealing seat 11. In this way, during the pressure relief
operation, the valve membrane C can lift only on one side, of a length L', smaller
than L, and equal to the distance between the second rib 8 and the non-fixed end of
the valve membrane 12. During the pressure relief operation, the portion of the membrane
which lifts also bends, rotating around the second rib 8. The second rib 8 may extend
along the valve cap C, between any two points of the peripheral border, parallel to
the first rib 2 but so as to be nearer to the pressure relief opening 4.
[0062] As shown in Figure 2A, the first rib 2 and the second rib 8 divide the membrane C
into three portions: a first portion free to lift due to the effect of the gas under
pressure contained in the container on which the valve is applied, a second portion
between the two ribs 2 and 8 and a third portion. The second and third portion cannot
lift. The first portion, seen in section, has length L'. The length L' can be equal
at least to half of the maximum length of the valve membrane. Preferably, the predefined
length L' can be 2/3 (two thirds) of the maximum length of the valve membrane C. The
first portion is the only portion of the valve membrane C which lifts due to the effect
of the gas under pressure contained in the container on which the valve is applied.
[0063] The valve 1 according to the embodiment shown in Figure 2C has a valve body A with
a circular shape. Moreover, also the housing for the valve cap B has a circular shape.
The valve cap B and the valve membrane C are circular. More in particular, the valve
cap B can be placed in the housing in the valve body A so as to close the valve 1.
The first rib 2 is made along a chord of the valve cap B and the second rib 8 is made
along a second chord of the valve cap B parallel to the first chord on which the first
rib 2 is made and so as to be nearer to the pressure relief opening 4 with respect
to it. The second rib 2 extends along the entire length of the second chord. The second
rib may be a continuous line or a non continuous line, for example, it can be a line
formed by a series of two or more sections separated by empty space.
[0064] The advantages due to the presence of the second rib 8 are the ones already cited
for the first rib 2 and, therefore, related to the security with which the one-way
functionality of the pressure relief valve 1 is ensured. In addition, in this case,
since the length L' of which the membrane C can lift during the pressure relief operation
is smaller than the length L, an opening pressure limit, of the pressure relief valve
1, inside the hermetic container, higher than for the pressure relief valve 1 shown
in Figures 1A to 1E is ensured. More in particular, depending on the needs, valves
can be made having the second rib 8 positioned so that the valve membrane C can laterally
lift of different lengths L', according to the opening pressure limit needed.
[0065] Also in this embodiment the valve cap B is wedge in the valve body A, as described
above, with reference to Fig. 1F.
[0066] Figures 3A and 3B schematically show a pressure relief one-way valve according to
a further embodiment, not claimed.
[0067] Figures 3A and 3B correspond to Figures 1A and 1B, respectively, and show a pressure
relief one-way valve according to the same prospective already indicated. The difference
between the valve shown in Figures 1A and 1B and the one shown in Figures 3A and 3B
is that the valve 1 shown in Figures 3A and 3B comprises a valve body A with a border
10 higher than the upper surface of the valve cap B. In particular, in the cross section
view of Figure 3A it is possible to see that the border 10 of the valve body A is
placed at an upper level with respect to the upper surface of the valve cap B, facing
the outside of the valve. Figures 4A and 4B correspond to Figures 2A and 2B, respectively,
and show a pressure relief one-way valve according to the same prospective already
indicated. The difference between the valve shown in Figures 2A and 2B and the one
shown in Figures 4A and 4B consists in that the valve 1 shown in Figures 4A and 4B
comprises a valve body with a border 10 higher than the upper surface of the valve
cap B, in particular, in the cross section view of Figure 4A it is possible to see
that the border 10 of the valve body A is placed at an upper level with respect to
the upper surface of the valve cap B facing the outside of the valve.
[0068] According to the present invention, a method is provided for the production of a
pressure relief one-way valve which comprises a valve body A, a valve cap B, and a
valve membrane C, in which the valve body A comprises a base comprising a sealing
seat 11 for the valve membrane C and one or more holes 6 suitable to let the gas pass
through the valve 1, in which the valve B is placed in the valve body A and comprises
a pressure relief opening 4 and in which the valve membrane C is flexible and is placed
between the valve body A and the cap B in the sealing seat 11.
[0069] In particular, the method for manufacturing a one-way valve 1 according to the present
invention comprises the following step: formation in the valve cap B of a first rib
2 placed laterally with respect to the pressure relief opening 4 so as to block the
valve membrane C in the sealing seat 11 so that the valve membrane C is free to lift
during the pressure relief operation, only on one side and so that the free to lift
portion of the valve membrane C has a length L, equal to or less than the distance
between the first rib 2 and the non-fixed end of the valve membrane C. According to
the present invention, the valve body A and/or the valve cap B can be injection moulded.
[0070] According to the present invention, the method for manufacturing a one-way valve
further comprises the following step: formation in the valve cap B of a second rib
8, placed on the same side of the valve cap B with respect to the pressure relief
opening 4 on which the first rib 2 is placed, so that the portion of the valve membrane
C free to lift during the pressure relief operation has a fixed length L', less than
the distance L between the first rib 2 and the non-fixed end 12 of the valve membrane
C. Also in this case the valve body A and/or the valve cap B can advantageously be
injection moulded.
[0071] According to a further particularly advantageous embodiment of the present invention,
the valve membrane C is obtained from a film, cut and inserted in its sealing seat
11 inside the valve body A, in one single operation. In particular, the cut of the
valve membrane C from the film and its placing into the sealing seat 11 of the valve
body A are performed in a single step of the method for manufacturing a one way valve
according to an embodiment of the present invention.
[0072] This is schematically shown in Fig. 5. The film 17 made of the same material of which
the valve membrane C is made, is transported from an unwinding bobbin 16 to a winding
bobbin 18. The sliding of the film can be assisted by using one or more guides 21
and 22, for example, by using guiding rollers. Between the bobbins 16 and 17 one or
more cutters can be placed. In the case shown in the Figures, two cutters 19 and 20
are shown, but the number of cutters is not limited to this value. The valve body
A is placed in correspondence to one cutter 19 so that the cutter does not only cut
the valve membrane C from the film 17, but also pushes the cut valve membrane C directly
inside the sealing seat 11 of the valve body A. In practice, every cutter 19, 20 is
configured so as to contemporarily carry out the cutting and the placing of the valve
membrane in the sealing seat 11 of the valve body. For example, in the system shown
in Figure 5, the cutter 19 lowers down to cut the valve membrane C from the film 17
and then continues its run downwards pushing the newly cut membrane C inside the sealing
seat 11 of the valve body A.
[0073] The valve 1 so obtained has considerably reduced production costs, since the valve
membrane C, which is placed into the seat as shown in Figure 5, has production costs
lower with respect to a rubber valve membrane, which has to be transported from the
place in which it is produced to the place in which the valve is assembled.
[0074] Although the present invention has been described with reference to the embodiments
described above, it is clear for the skilled person that several modifications, variations
and improvements of the present invention may be made, in view of the teaching described
above and within the scope of the appended claims, without departing from the object
and the scope of protection of the invention.
[0075] For example, even if the pressure relief one-way valves having a circular shape have
been shown, it is clear that these can be properly made in different shapes, for example,
polygonal, such as square or hexagonal.
[0076] Moreover, the valves according to the present invention may have different dimensions
and thicknesses. For example, according to an embodiment of the present invention
the valve can have a diameter of about 2 cm and a thickness of about 0.4 cm. However,
different ranges of sizes for these quantities are allowable.
[0077] Additionally, those aspects which are deemed to be known by the skilled person have
not been described in order to avoid unduly obfuscating the described invention. Consequently,
the invention is not limited by the embodiments described above but is only limited
by the scope of protection of the appended claims.
REFERENCE SIGNS
[0078]
1: Pressure relief valve;
A: Valve body;
B: Valve cap;
C: Valve membrane;
O: Center of the valve cap
L, L': Length of the portion of the valve membrane which is free to lift;
2: The first rib of the valve cap;
3: Protruding element;
4: Pressure relief opening of the valve cap;
5: Layer of silicone oil;
6: Through holes of the valve body;
7: Filter element;
8: Second rib of the valve cap;
10: Flat rim of the valve cap;
11: Sealing seat of the valve membrane;
12: Non-fixed end of the valve membrane;
13: Base of the valve body;
14: Indentation of the valve body;
15: Protrusion of the valve cap;
16: Unwinding bobbin
17: Film from which the valve membrane is obtained
18: Winding bobbin;
19, 20: Cutters
21, 22: Guides
1. Pressure-relief one-way valve (1) for hermetic packaging, comprising a valve body
(A), a valve cap (B) and a valve membrane (C), wherein said valve body (A) comprises
a base (13) comprising a sealing seat (11) for said valve membrane (C) and one or
more holes (6) adapted to let the gas flow through the valve (1), wherein said valve
cap (B) is housed in said valve body (A) and comprises a pressure-relief opening (4)
and wherein said valve membrane (C) is flexible and is placed between said valve body
(A) and said valve cap (B) in said sealing seat (11), wherein said valve cap (B) comprises
a first rib (2) placed laterally with respect to said pressure-relief opening (4)
so as to keep said valve membrane (C) in said sealing seat (11) so that said valve
membrane (C) can lift, during the pressure-relieve operation, only on one side and
so that the portion of said valve membrane (C) free to lift has a length (L, L') equal
to or less than the distance between said first rib (2) and the non-fixed end (12)
of said valve membrane (C),characterized in that: said valve cap (B) comprises a second rib (8), placed on the same side of the valve
cap (B) with respect to said pressure-relief opening (4) on which said first rib (2)
is placed, so that the portion of said valve membrane (C) free to lift, during the
pressure-relief operation has a fixed length (L') smaller than the distance between
said first rib (2) and said non-fixed end (12) of said valve membrane (C).
2. Pressure-relief one-way valve (1) according to claim 1, characterized in that said fixed length, (L, L') is equal to at least half of the maximum width of said
valve membrane (C), preferably at least two thirds or four fifths of the maximum width
of the valve membrane (C).
3. Pressure-relief one-way valve (1) according to any of the previous claims, characterized in that said pressure-relief opening (4) is in the center of said valve cap (B).
4. Pressure-relief one-way valve (1) according to any of the previous claims, characterized in that said valve membrane (C) has a thickness comprised between 10 micron and 100 micron,
preferably between 40 micron and 60 micron, preferably equal to 50 micron.
5. Pressure-relief one-way valve (1), according to any of the previous claims, characterized in that said valve cap (B) further comprises a projecting element (3) adapted to limit the
bend of said valve membrane (C) during the pressure-relief operation.
6. Pressure-relief one-way valve (1), according to any of the previous claims, characterized in that the upper surface of said valve cap (B) is coplanar with the upper surface of said
valve body (A).
7. Pressure-relief one-way valve (1) according to any of claims 1 to 5, characterized in that the upper surface of said valve cap (B) is on a lower level with respect to the upper
surface of said valve body (A)..
8. Pressure-relief one-way valve (1) according to any of the previous claims, characterized in that said valve cap (B) is symmetric with respect to a plane (X) parallel to said base
(13) of said valve body (A) and going through the center (O) of said valve cap (B)
so that said valve cap (B) has not to be pre-oriented according to a preferential
orientation to be placed into the valve body (A).
9. Pressure-relief one-way valve (1) according to any of the previous claims, characterized in that said sealing seat (11) is covered by a viscous layer (5), for example silicone oil,
so as to improve the sealing of said valve membrane (C).
10. Pressure-relief one-way valve (1) according to any of the previous claims, characterized in that it further comprises a filtering element (7) adapted to filter the gas that flows
through said one or more holes (6) of said valve body (A)
11. Pressure-relief one-way valve (1) according to claim 10, characterized in that said filtering element (7) comprises a non woven polyester, for example SMASH™.
12. Pressure-relief one-way valve (1) according to one of claims 10 or 11, characterized in that said filtering element (7) is impermeable to liquids.
13. Pressure-relief one-way valve (1) according to any of the previous claims, characterized in that said valve body (A) and/or said valve cap (B) are made of biodegradable material,
for example oxo-biodegradable material.
14. Pressure-relief one-way valve (1) according to any of the previous claims, characterized in that said valve membrane (C) comprises a non-biodegradable material, for example PET.
15. Pressure-relief one-way valve (1) according to any of the previous claims, characterized in that the weight of said valve membrane (C) is equal to 0.1% or less of the total weight
of said valve (1), for example equal to 0.06% of the total weight of said valve (1).
16. Hermetic container, preferably for food products, characterized in that it comprises a valve according one of claims 1 to 15.
17. Method for manufacturing a pressure relief one way valve (1) for hermetic packaging,
comprising a valve body (A), a valve cap (B) and a valve membrane (C), wherein said
valve body (A) comprises a base comprising a sealing seat (11) for said valve membrane
(C) and one or more holes (6) adapted to let the gas flow through the valve (1), wherein
said valve cap (B) is housed in said valve body (A) and comprises a pressure-relief
opening (4) and wherein said valve membrane (C) is flexible and it is placed between
said valve body (A) and said valve cap (B) in said sealing seat (11), wherein said
method comprises the following step: formation in said valve cap (B) of a first rib
(2) placed laterally with respect to said pressure-relief opening (4) so as to keep
said valve membrane (C) in said sealing seat (11) so that said valve membrane (C)
can lift, during the pressure-relieve operation, only on one side and so that the
portion of said valve membrane (C) free to lift has a length (L, L') equal to or less
than the distance between said first rib (2) and the non-fixed end (12) of said valve
membrane (C), characterized in that: said method further comprises: formation in said valve cap (B) of a second rib (8)
placed on the same side of the valve cap (B) with respect to said pressure relief
opening (4) on which said first rib (2) is placed, so that the portion of said valve
membrane (C) free to lift, during the pressure relief operation has a fixed length
(L') less than the distance between said first rib (2) and said non-fixed end (12)
of said valve membrane (C).
18. Method for the production of a pressure-relief one-way valve (1) according to claim
17, characterized in that said valve membrane (C) is cut from tape and placed in said sealing seat (11) of
said valve body (A) in a single method step.
1. Einweg-Druckablassventil (1) für hermetische Verpackungen, das einen Ventilkörper
(A), eine Ventilkappe (B) sowie eine Ventilmembran (C) umfasst, wobei der Ventilkörper
(A) eine Basis (13), die eine abdichtende Aufnahme (11) für die Ventilmembran (C)
und ein Loch oder mehrere Löcher (6) umfasst, das/die so eingerichtet ist/sind, dass
sie das Gas durch das Ventil (1) strömen lässt/lassen, wobei die Ventilkappe (B) in
dem Ventilkörper (A) aufgenommen ist und eine Druckablassöffnung (4) umfasst und die
Ventilmembran (C) flexibel ist und zwischen dem Ventilkörper (A) und der Ventilkappe
(B) in der abdichtenden Aufnahme (11) positioniert ist, die Ventilkappe (B) einen
ersten Steg (2) umfasst, der seitlich in Bezug auf die Druckablassöffnung (4) positioniert
ist, um die Ventilmembran (C) in der abdichtenden Aufnahme (11) zu halten, so dass
sich die Ventilmembran (C) während des Druckablassvorgangs an nur einer Seite anheben
kann und der Abschnitt der Ventilmembran (C), der sich anheben kann, eine Länge (L,
L') hat, die genauso groß ist wie oder kleiner als der Abstand zwischen dem Steg (2)
und dem nicht befestigten Ende (12) der Ventilmembran (C),
dadurch gekennzeichnet, dass:
die Ventilkappe (B) einen zweiten Steg (8) umfasst, der an der gleichen Seite der
Ventilkappe (B) in Bezug auf die Druckablassöffnung (4) positioniert ist, an der der
erste Steg (2) positioniert ist, so dass der Abschnitt der Ventilmembran (C), der
sich anheben kann, während des Druckablassvorgangs eine unveränderliche Länge (L')
hat, die kleiner ist als der Abstand zwischen dem ersten Steg (2) und dem nicht befestigten
Ende (12) der Ventilmembran (C).
2. Einweg-Druckablassventil (1) nach Anspruch 1, dadurch gekennzeichnet, dass die unveränderliche Länge (L, L') mindestens so groß ist wie die Hälfte der maximalen
Breite der Ventilmembran (C), vorzugsweise wenigstens zwei Drittel oder vier Fünftel
der maximalen Breite der Ventilmembran (C).
3. Einweg-Druckablassventil (1) nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass sich die Druckablassöffnung (4) in der Mitte der Ventilkappe (B) befindet.
4. Einweg-Druckablassventil (1) nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die Ventilmembran (10) eine Dicke hat, die zwischen 10 µm und 100 µm, vorzugsweise
zwischen 40 µm und 60 µm, vorzugsweise 50 µm beträgt.
5. Einweg-Druckablassventil (1)'nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die Ventilkappe (B) des Weiteren ein vorstehendes Element (3) umfasst, das so eingerichtet
ist, dass es die Biegung der Ventilmembran (C) während des Druckablassvorgangs einschränkt.
6. Einweg-Druckablassventil (1) nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die obere Fläche der Ventilkappe (B) koplanar mit der oberen Fläche des Ventilkörper
(A) ist.
7. Einweg-Druckablassventil (1) nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass sich die obere Fläche der Ventilkappe (B) in einer geringeren Höhe befindet als die
obere Fläche des Ventilkörpers (A).
8. Einweg-Druckablassventil (1) nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die Ventilkappe (W) symmetrisch in Bezug auf eine Ebene (X) ist, die parallel zu
der Basis (13) des Ventilkörpers (A) ist und durch die Mitte (O) der Ventilkappe (B)
hindurch verläuft, so dass die Ventilkappe (B) nicht im Voraus in einer bevorzugten
Ausrichtung ausgerichtet werden muss, um sie in dem Ventilkörper (A) zu positionieren.
9. Einweg-Druckablassventil (1) nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die abdichtende Aufnahme (11) mit einer viskosen Schicht (5), beispielsweise aus
Silikonöl, überzogen ist, um die Abdichtung der Ventilmembran (10) zu verbessern.
10. Einweg-Druckablassventil (1) nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet dass es des Weiteren ein Filterelement (7) umfasst, das so eingerichtet ist, dass es das
Gas filtert, das durch das eine Loch bzw. die mehreren Löcher (6) des Ventilkörpers
(A) hindurchströmt.
11. Einweg-Druckablassventil (1) nach Anspruch 10, dadurch gekennzeichnet, dass das Filterelement (7) ein Polyester-Vlies, beispielsweise SMASH™, umfasst.
12. Einweg-Druckablassventil ein nach einem der Ansprüche 10 oder 11, dadurch gekennzeichnet, dass das Filterelement (7) undurchlässig für Flüssigkeiten ist.
13. Einweg-Druckablassventil (1) nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass der Ventilkörper (A) und/oder die Ventilkappe (B) aus biologisch abbaubaren Material,
beispielsweise OXO-abbaubarem Material, bestehen/besteht.
14. Einweg-Druckablassventil (1) nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass die Ventilmembran (C) ein nicht biologisch abbaubares Material, beispielsweise PET,
umfasst.
15. Einweg-Druckablassventil (1) nach einem der vorangehenden Ansprüche, dadurch gekennzeichnet, dass das Gewicht der Ventilmembran (C) 0,1 % oder weniger des Gesamtgewichtes des Ventils
(1), beispielsweise 0,06 % des Gesamtgewichtes des Ventils (1), beträgt.
16. Hermetischer Behälter, vorzugsweise für Lebensmittelerzeugnisse, dadurch gekennzeichnet, dass er ein Ventil nach einem der Ansprüche 1 bis 15 umfasst.
17. Verfahren zum Herstellen eines Einweg-Druckablassventils (1) für hermetische Verpackungen,
das einen Ventilkörper (A), eine Ventilkappe (B) sowie eine Ventilmembran (C) umfasst,
wobei der Ventilkörper (A) eine Basis (13), die eine abdichtende Aufnahme (11) für
die Ventilmembran (C) und ein Loch oder mehrere Löcher (6) umfasst, das/die so eingerichtet
ist/sind, dass sie das Gas durch das Ventil (1) strömen lässt/lassen, wobei die Ventilkappe
(B) in dem Ventilkörper (A) aufgenommen ist und eine Druckablassöffnung (4) umfasst
und die Ventilmembran (C) flexibel ist und zwischen dem Ventilkörper (A) und der Ventilkappe
(B) in der abdichtenden Aufnahme (11) positioniert ist, und das Verfahren den folgenden
Schritt umfasst:
Ausbilden eines ersten Stegs (2) in der Ventilkappe (B), der seitlich in Bezug auf
die Druckablassöffnung (4) positioniert ist, um die Ventilmembran (C) in der abdichtenden
Aufnahme (11) zu halten, so dass sich die Ventilmembran (C) während des Druckablassvorgangs
an nur einer Seite anheben kann und der Abschnitt der Ventilmembran (C), der sich
anheben kann, eine Länge (L, L') hat, die genauso groß ist wie oder kleiner als der
Abstand zwischen dem Steg (2) und dem nicht befestigten Ende (12) der Ventilmembran
(C), dadurch gekennzeichnet, dass das Verfahren des Weiteren umfasst:
Ausbilden eines zweiten Stegs (8) in der Ventilkappe (B), der an der gleichen Seite
der Ventilkappe (B) in Bezug auf die Druckablassöffnung (4) positioniert ist, an der
der erste Steg (2) positioniert ist, so dass der Abschnitt der Ventilmembran (C),
der sich anheben kann, während des Druckablassvorgangs eine unveränderliche Länge
(L') hat, die kleiner ist als der Abstand zwischen dem ersten Steg (2) und dem nicht
befestigten Ende (12) der Ventilmembran (C).
18. Verfahren für die Produktion eines Einweg-Druckablassventils, (1) nach Anspruch 17,
dadurch gekennzeichnet, dass die Ventilmembran (C) in einem einzelnen Verfahrensschritt aus Band geschnitten und
in der abdichtenden Aufnahme (11) des Ventilkörpers (A) positioniert wird.
1. Valve unidirectionnelle de surpression (1) pour emballage hermétique, comprenant un
corps de valve (A), une coiffe de valve (B) et une membrane de valve (C), dans laquelle
ledit corps de valve (A) comprend une base (13) comportant un siège de scellement
(11) pour ladite membrane de valve (C) et un ou plusieurs trous (6) conçus pour permettre
l'écoulement du gaz à travers la valve (1), dans laquelle ladite coiffe de valve (B)
est logée dans ledit corps de valve (A) et comporte une ouverture de libération de
pression (4) et dans laquelle ladite membrane de valve (C) est souple et est placée
entre ledit corps de valve (A) et ladite coiffe de valve (B) dans ledit siège de scellement
(11), dans laquelle ladite coiffe de valve (B) comporte une première nervure (2) disposée
latéralement par rapport à ladite ouverture de libération de pression (4) de manière
à maintenir ladite membrane de valve (C) dans ledit siège de scellement (11) de façon
que ladite membrane de valve (C) puisse se soulever, pendant la libération de pression,
seulement sur un côté et que la partie de ladite membrane de valve (C) libre de se
soulever ait une longueur (L, L') égale ou inférieure à la distance entre ladite première
nervure (2) et l'extrémité non fixée (12) de ladite membrane de valve (C), caractérisée en ce que : ladite coiffe de valve (B) comporte une seconde nervure (8) située sur le même
coté de la coiffe de valve (B) que ladite première nervure (2) par rapport à ladite
ouverture de libération de pression (4), de façon que la partie de ladite membrane
de valve (C) libre de se soulever pendant la libération de pression ait une longueur
fixe (L') inférieure à la distance entre ladite première nervure (2) et ladite extrémité
non fixée (12) de ladite membrane de valve (C).
2. Valve unidirectionnelle de surpression (1) selon la revendication 1, caractérisée en ce que ladite longueur fixe (L, L') est égale à au moins la moitié de la largeur maximale
de ladite membrane de valve (C), de préférence au moins deux tiers ou quatre cinquièmes
de la largeur maximale de la membrane de valve (C).
3. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
précédentes, caractérisée en ce que ladite ouverture de libération de pression (4) se trouve au centre de ladite coiffe
de valve (B).
4. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
précédentes, caractérisée en ce que ladite membrane de valve (C) a une épaisseur comprise entre 10 microns et 100 microns,
de préférence entre 40 microns et 60 microns, de préférence égale à 50 microns.
5. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
précédentes, caractérisée en ce que ladite coiffe de valve (B) comporte en outre un élément saillant (3) conçu pour limiter
le fléchissement de ladite membrane de valve (C) pendant la libération de pression.
6. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
précédentes, caractérisée en ce que la surface supérieure de ladite coiffe de valve (B) est coplanaire avec la surface
supérieure dudit corps de valve (A).
7. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
1 à 5, caractérisée en ce que la surface supérieure de ladite coiffe de valve (B) se trouve à un niveau inférieur
rapport à la surface supérieure dudit corps de valve (A).
8. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
précédentes, caractérisée en ce que ladite coiffe de valve (B) est symétrique par rapport à un plan (X) parallèle à ladite
base (13) dudit corps de valve (A) et passant par le centre (O) de ladite coiffe de
valve (B), de sorte que ladite coiffe de valve (B) n'a pas besoin d'être préalablement
orientée selon une orientation préférentielle pour être introduite dans le corps de
valve (A).
9. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
précédentes, caractérisée en ce que ledit siège de scellement (11) est couvert d'une couche visqueuse (5), par exemple
de l'huile de silicone, de manière à améliorer le scellement de ladite membrane de
valve (C).
10. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
précédentes, caractérisée en ce qu'elle comprend, en outre, un élément filtrant (7) conçu pour filtrer le gaz qui s'écoule
à travers lesdits un ou plusieurs trous (6) dudit corps de valve (A).
11. Valve unidirectionnelle de surpression (1) selon la revendication 10, caractérisée en ce que ledit élément filtrant (7) comprend un polyester non tissé, par exemple SMASH™.
12. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
10 ou 11, caractérisée en ce que ledit élément filtrant (7) est imperméable aux liquides.
13. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
précédentes, caractérisée en ce que ledit corps de valve (A) et/ou ladite coiffe de valve (B) est/sont formé/s d'un matériau
biodégradable, par exemple un matériau oxo-biodégradable.
14. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
précédentes, caractérisée en ce que ladite membrane de valve (C) comprend un matériau non biodégradable, par exemple
du PET.
15. Valve unidirectionnelle de surpression (1) selon l'une quelconque des revendications
précédentes, caractérisée en ce que le poids de ladite membrane de valve (C) représente 1% ou moins de 1% du poids total
de ladite valve (1), par exemple 0,06% du poids total de ladite valve (1).
16. Contenant hermétique, de préférence pour produits alimentaires, caractérisé en ce qu'il comprend une valve selon l'une des revendications 1 à 15.
17. Procédé de fabrication d'une valve unidirectionnelle de surpression (1) pour emballage
hermétique, comprenant un corps de valve (A), une coiffe de valve (B) et une membrane
de valve (C), dans lequel ledit corps de valve (A) comprend une base comportant un
siège de scellement (11) pour ladite membrane de valve (C) et un ou plusieurs trous
(6) conçus pour permettre l'écoulement du gaz à travers la valve (1), dans lequel
ladite coiffe de valve (B) est logée dans ledit corps de valve (A) et comporte une
ouverture de libération de pression (4) et dans lequel ladite membrane de valve (C)
est souple et est placée entre ledit corps de valve (A) et ladite coiffe de valve
(B) dans ledit siège de scellement (11), dans lequel ledit procédé comprend l'étape
suivante : formation dans ladite coiffe de valve (B) d'une première nervure (2) disposée
latéralement par rapport à ladite ouverture de libération de pression (4) de manière
à maintenir ladite membrane de valve (C) dans ledit siège de scellement (11) de façon
que ladite membrane de valve (C) puisse se soulever, pendant la libération de pression,
seulement sur un côté et que la partie de ladite membrane de valve (C) libre de se
soulever ait une longueur (L, L') égale ou inférieure à la distance entre ladite première
nervure (2) et l'extrémité non fixée (12) de ladite membrane de valve (C), caractérisé en ce que : ledit procédé comprend, en outre : la formation dans ladite coiffe de valve (B)
d'une seconde nervure (8) située sur le même coté de la coiffe de valve (B) que ladite
première nervure (2) par rapport à ladite ouverture de libération de pression (4),
de façon que la partie de ladite membrane de valve (C) libre de se soulever pendant
la libération de pression ait une longueur fixe (L') inférieure à la distance entre
ladite première nervure (2) et ladite extrémité non fixée (12) de ladite membrane
de valve (C).
18. Procédé de production d'une valve unidirectionnelle de surpression (1) selon la revendication
17, caractérisé en ce que ladite membrane de valve (C) est coupée dans un ruban et placée dans ledit siège
de scellement (11) dudit corps de valve (A) en une unique étape de procédé.