ES2601224T3 - Oil-free and dampened pressure relief valves that have an integrated filter - Google Patents

Abstract

A unidirectional pressure relief valve (310) for fixing on a vent on an outer surface of a closed container (11) containing a product that produces gas, having the pressure relief valve (310) - a filter layer ( 316) of a strip type material having a periphery (320) and first and second sides (322, 324) defining a body (326) therebetween, the filter layer (316) having a filter element (328 ) which defines opening and barrier portions (330, 332) in the strip-like material that provide a passage of gas through the opening portions (330) and the body (326) and the obstruction of particulate matter by the barrier portions (332); - adhesive (20) on the second side of the filter layer (324) to adhere the pressure relief valve (310) to the outer surface of the closed container (11); and - a flexible joint (318) that includes a flexible cover (44) selectively joined to the first side of the filter layer (322) to form a gas flow path (21) between the flexible cover (44) and the first side of the filter layer (322) along an unbound area of the flexible cover (44) and the filter layer (316) from the filter element (328) to the periphery of the filter layer (320) characterized in that - the flexible seal (318) also includes a first gas impermeable layer (26) above the filter layer (316) and around the opening portions (330) and a second gas impermeable layer (32) supported by the flexible cover (44) on the opening portions (330) of the filter layer (316), the gas impermeable layers (26, 32) having a surface attraction that maintains a gas impermeable layer against the other, the gasket having flexible (318) a first position in which the gas impermeable layers (26, 32) form a jun ta to obstruct the flow of gas through the body and an additional position in which the second gas impermeable layer of the unbound area is at least partially spaced from the first gas impermeable layer by the gas pressure exerted through the filter element (328) to allow unidirectional gas outflow through the gas flow path (21) whereby the pressure relief valve (310) allows unidirectional pressure gas outflow from a inside the closed container (11) through the filter element (328) and the gas flow path (21) while preventing particulate matter from interfering with the closing of the valve (310) once it is reduced the gas pressure inside the container (11).

Description

DESCRIPTION

Oil-free and dampened pressure relief valves that have an integrated filter.

[0001] This invention generally relates to unidirectional pressure relief valves that apply to the

packaging for products, such as coffee, and more specifically to an improved pressure relief valve that has an integrated filter and can be used without a wetting agent.

BACKGROUND OF THE INVENTION

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[0002] US7,178,555 describes a one-way pressure relief valve that can be

fixed to a product packaging to vent the pressurized gases of the packaging. In addition, unidirectional pressure relief valves, such as PLITEK PLI-VALV PV-28 pressure relief valves, are applied to the packaging for products, such as coffee, to allow unwanted gases to be vented from the packaging in 15 so much that sealing the passage of atmospheric gases. Such valves may vary in material and construction depending on the application of the packaging. The valves can be made, for example, of plastic or sheet metal, and are generally self-adhesive, thin, low-profile designs supplied in a polyester lining or of anti-tear paper.

[0003] Valves are usually attached to the product package with a heat-sealed or sensitive adhesive.

the pressure. An adhesive on the back side of the valves can initially mount the valves on the liner. The valves are removed from the liner and the adhesive is used to attach a valve to the container.

[0004] In operation, the valves open at a target pressure and then close at a lower target pressure, whose values depend on the application of the packaging, after the pressure within the

packing drops. The valves ventilate unwanted gases and seal the passage of atmospheric gases from the rigid or flexible packaging or other closures. An advantage of such valves is that they allow a product, such as coffee, to be packaged immediately after roasting and grinding to preserve the freshness of the product. Such unidirectional pressure relief valves allow a product, such as coffee, to degas during packing and transport, while reducing oxidation of the product. The use of such valves allows the elimination of a bulk degassing procedure of the product before packaging. This not only accelerates the procedure as a whole, saving time and money, and space, but also reduces the exposure of the product to oxidation. In this way the product, such as coffee, is provided to consumers at a higher level of freshness and quality.

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[0005] A sealing lubricant (also known as a wetting agent), such as silicone impregnated oil or graphite, can be added between the membrane layers of the valve to moisten the relevant surfaces of the valve to facilitate closure of the valve. The addition of a sealing lubricant to moisten the relevant valve surfaces is typically done just before applying the valve to the packaging. In

In operation, the dry strip membrane of such prior art valves is allowed to flex away from an orifice to vent unwanted gases into the package at the time of reaching the opening pressure determined by the application. When the pressure drops to the closing pressure determined by the application, the dry strip in cooperation with the sealing lubricant that moistens the dry strip, flexes back towards the hole closing the valve and preventing atmospheric gases from entering the packaging.

Four. Five

[0006] Unidirectional pressure relief valves that include a wetting agent are excellent for their intended purpose. However, the stage of lubricating the valves with a wetting agent adds time and cost and is another factor to be controlled in the procedure of applying the valves. Although the moistened valve is often fixed to the outside of the packaging, there may be cases in which it is desirable to place the

The valve inside the package with the product and the inclusion of a wetting agent may not be possible because the wetting agent could come into contact with the product. Therefore, there is a need for a one-way pressure relief valve that does not require the addition of a lubricant.

[0007] WO2011 / 056709A1 describes a gas release valve for releasing gas from the inside of a coffee container, the valve having a narrow dry strip of flexible material between a base and a

covering material with the narrow dry strip being placed on patterns of vents spaced at the base and being pre-greased with a layer of oil. The oil layer between the dry strip and the base works to join the lower face of the dry strip and the upper surface of the base as a result of the surface tension of the oil. This, together with the wetting force provided by the oil coating provides a seal

practically complete of the ventilation hole when the dry strip rests on the upper surface of the base.

[0008] There is also still a need that affects pressure relief valves

5 unidirectional in general which is to protect the pressure relief valves from being clogged by matter in fine particles, such as particles inside the packaging to which a valve is attached. The fouling of the unidirectional pressure relief valve may interfere with the operation of the valve and may prevent the valve from closing completely. Incomplete closure of the valve may allow air to enter the container, damaging the product inside the container. Therefore, there is a need for a unidirectional pressure relief valve that prevents fouling of the valve and contributes to an improved operation of the unidirectional pressure relief valve.

SUMMARY OF THE INVENTION

[0009] Certain embodiments of the present invention are related to providing a valve of

Unidirectional pressure relief for application to product packaging without requiring the addition of a sealing lubricant to moisten the sealing portions of the pressure relief valve. Other examples of unidirectional pressure relief valve that are not according to the invention may include such a sealing lubricant and humectant for optimal operation. A filter integrated with the pressure relief valve prevents the particles from entering the pressure relief valve, providing improved operation of the valve.

[0010] In examples, a unidirectional pressure relief valve may include a gas impermeable base layer having an upper part, a lower part, and an orifice that extends through the base layers from the upper part to the bottom. A flexible joint cooperates with the base layer to open and

25 close the pressure relief valve. A flexible joint may include a layer of gas-like adhesive similar to the base layer and around the base layer hole. In addition, a silicone-coated membrane or other gas-impermeable shedding film covers the base layer hole with the shedding film in contact with the adhesive-like material creating a surface attraction between the shedding film and the similar material. to an adhesive to close the pressure relief valve. 30 When the pressure inside the container exceeds an objective pressure, the layer of adhesive-like material and the release film-coated membrane are separated allowing gas to flow between them and out of the pressure relief valve through a gas flow path.

[0011] The sheathing film coated membrane covering the hole that extends through the base layer 35 may not extend to the edges of the layer of material similar to an adhesive in a

direction, and may not extend to the edges of the base layer in one direction.

[0012] A gas impermeable adhesive layer having a thickness located at the bottom of the base may be provided to fix the base to the packaging. The adhesive layer preferably has a hole,

40 generally aligned with the hole that extends through the base layer, which extends entirely through the adhesive layer.

[0013] A flexible gasket may further include a gas impermeable cover layer and a gas impermeable adhesive layer between the cover layer and the silicone coated membrane or other film of

45 detachment, opposite to silicone or other release film.

[0014] The unidirectional pressure relief valve may also have a gas impermeable intermediate layer having an upper part and a lower part between the layer of adhesive-like material and the base with an orifice that extends through the intermediate layer from the top to the bottom and

50 generally aligned with the hole in the base and the hole in the layer of adhesive-like material. The unidirectional pressure relief valve may also have a layer of filter material between the holes in the intermediate layer and the base, a gas impermeable layer of adhesive between the intermediate layer and the layer of filter material, and a hole that it extends through the layer of adhesive between the intermediate layer and the layer of filter material. The hole may generally be aligned with the holes in the layer of adhesive-like material, the intermediate layer and the base.

[0015] The hole in the base may be larger than the holes in the intermediate layer and the adhesive layer between the intermediate layer and the layer of filter material. The filter material layer can be secured around its periphery by a portion of the adhesive layer between the intermediate layer and the material layer

of filter, and the layer of filter material may be recessed in the hole in the base.

[0016] A plurality of holes of one size to prevent the passage of the product into the holes of the intermediate layer and the base may be included in the layer of filter material.

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[0017] A gas impermeable layer of adhesive may be included between the layer of filter material and the base with a hole that extends through the layer of adhesive between the layer of filter material and the base. The hole may generally be aligned with the holes in the layer of adhesive-like material, the intermediate layer, the adhesive layer between the intermediate layer and the filter material layer, and the base.

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[0018] The layer of filter material may include a plurality of holes of a size to prevent the passage of the product into the hole of the intermediate layer towards the sealing and operating portions of the valve in the area of generally aligned holes that are they extend through the layer of adhesive-like material, the intermediate layer and the adhesive layer between the intermediate layer and the filter material layer.

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[0019] The layer of filter material can prevent the passage of liquid while allowing gas to escape, and it can be an expanded polytetrafluoroethylene material, a breathable liquid-proof textile material, or hydrophobic material, or an oleophobic material .

[0020] In another example that is not according to the invention, a new pressure relief valve is described for

Application to product packaging. Such an example has a gas impermeable base layer having an upper part and a lower part and a hole that extends through the base layer from the upper part to the lower part. A gas impermeable layer is provided on top of the base layer around the hole that extends through the base layer. It is provided with a gas impermeable intermediate layer having an upper part and a lower part between the layer above the base layer and the base and a hole extending through the intermediate layer from the upper part to the lower part and generally aligned with the hole in the base and the hole in the layer above the base layer. A layer of filter material is provided between the intermediate layer and the base aligned with the holes in the intermediate layer and the base. The layer of filter material is secured between the intermediate layer and the base by gas impermeable adhesive.

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[0021] The hole in the base may be larger than the holes in the intermediate layer and the adhesive layer between the intermediate layer and the layer of filter material; The layer of filter material may be secured around its periphery by a portion of the adhesive layer between the intermediate layer and the layer of filter material; and the layer of filter material may be recessed in the hole in the base.

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[0022] A plurality of holes of a size to prevent the passage of the product to the holes of the intermediate layer and the sealing and operating portions of the valve may be included in the layer of filter material.

[0023] A gas impermeable layer of adhesive may be included between the layer of filter material and the

base with a hole that extends through the adhesive layer between the layer of filter material and the base, and generally aligned with the holes in the layer above the base, the intermediate layer, the adhesive layer between the layer intermediate and filter material layer, and base.

[0024] The layer of filter material may include a plurality of holes of one size to prevent passage

from the product to the holes in the intermediate layer and the sealing and operating portions of the valve.

[0025] The layer of filter material can prevent the passage of liquid while allowing the escape of gas.

fifty

[0026] According to the invention, a unidirectional pressure relief valve is provided having the characteristics of claim 1.

[0027] Preferably, the openings defined by filter element may have a suitable form or shapes of any suitable type including shapes selected from the group consisting of circles, slits, spikes,

rectangles, and combinations thereof. The openings defined by the filter element may be arranged in one or more groups. Preferably, the filter element has a mesh size between approximately 30 mesh and 200 mesh.

[0028] Preferably, the second gas impermeable layer has a surface affinity attracted to the first gas impermeable layer to form a gasket therewith which blocks the passage of gas between the first and second gas impermeable layers. In the embodiments, the movement of the flexible joint to the additional position separates the first and second gas impermeable layers to allow gas to flow along the path of

5 gas flow between the first and second gas impermeable layers.

[0029] Other examples may be configured for optimal operation with a wetting fluid on the surface of the valve. In such examples, the flexible joint used in conjunction with the filter layer preferably comprises a closure without joining the filter element and superimposed on the opening portions. A

The cover layer has a second side that maintains the closure against the filter element when it is in the first position. The preferred cover layer has first and second flange zones or outer areas separated laterally and oriented to the first side of the filter layer. The flange areas are connected to the filter layer with the closure and the gas flow path between them. The movement of the cover layer to the additional position by gas pressure separates the closure of the opening portions to allow the gas to exit the pressure relief valve along the gas flow path. Other features and embodiments are described in the drawings and the detailed description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Exemplary pressure relief valves that have an integrated particle filter can

understood by reference to the following description taken in conjunction with the accompanying drawings, in which the same reference numbers identify the same elements throughout the different views. For convenience and brevity, the same reference numbers are used for the same parts between the embodiments. The drawings are not necessarily to scale, instead focusing on illustrating the principles of the invention. In the attached drawings:

fig. 1 is a plan view from above, on a reduced scale, of a fragment of a liner bearing a series of four exemplary pressure relief valves that are not according to the invention;

30 fig. 2 is an exploded perspective view of an example of a pressure relief valve that is not according to the invention;

fig. 3 is an exploded perspective view of an additional example of a pressure relief valve that is not according to the invention, but that includes an integrated filter;

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fig. 4 is an exploded perspective view of another example of a pressure relief valve that is not according to the invention with a membrane between the base layer and a bottom base layer that prevents particles from entering or penetrating, or into another variation, liquid, in the valve seal layer;

40 fig. 5 is an exploded perspective view of a preferred embodiment of a pressure relief valve according to the invention having an integrated filter;

fig. 6 illustrates the exemplary filter layer of the pressure relief valve of fig. 5;

45 fig. 6A is an enlarged view of an exemplary filter element taken along section 6A of fig. 6;

fig. 7 illustrates an additional exemplary filter layer;

50 fig. 7A is an enlarged view of an exemplary filter element taken along section 7A of fig. 7;

fig. 8 illustrates yet another exemplary filter layer;

55 fig. 8A is an enlarged view of an exemplary filter element taken along section 8A of fig. 8;

fig. 9 is an exemplary package that includes a pressure relief valve that has an integrated filter secured to an outer surface of the container;

fig. 10 is an exploded perspective view of the pressure relief valve of fig. 9;

fig. 11 is a sectional view of the pressure relief valve taken along section 11-11 of fig. 9 that

5 shows the valve in a closed state;

fig. 12 is a sectional view of the pressure relief valve taken along section 11-11 of fig. 9, but which shows the valve in a closed state;

10 fig. 13 is a plan view of the pressure relief valve of Fig. 12; Y

fig. 14 is a perspective view of the pressure relief valve of fig. 12.

DETAILED DESCRIPTION 15

[0031] As illustrated in figs. 1-14, the present description refers to an improved unidirectional pressure relief valve 10, 110, 210, 310 and 410 for application to a product package 11 (fig. 9) in which the gases have to be vented from the container 11 and atmospheric gases must be prevented from entering the container 11 through the pressure relief valve 10, 110, 210, 310 and 410. For convenience and brevity,

20 exemplary pressure relief valves 10, 110, 210, 310 and 410 are described for use with an exemplary container 11 of the type illustrated in fig. 9, it being understood that such pressure relief valves 10, 110, 210, 310 and 410 can be used with any suitable container such as those described herein.

[0032] Certain of the pressure relief valves exemplary 10, 110, 210 and 310 illustrated in figs. 1-5 or 25 require a lubricant to moisten and seal the valve of which figs. 1-4 do not show a valve

pressure relief according to the invention. The exemplary pressure relief valve 410 illustrated in figs. 9-14 is not according to the invention and is designed for optimal function when certain valve surfaces are moistened with a lubricant or other wetting agent.

[0033] Certain pressure relief valves 110, 210, 310 and 410 include an integrated filter. Such as

used herein, "integrated filter" means or refers to a filter that is a component part of the pressure relief valve 110, 210, 310 and 410.

[0034] Exemplary pressure relief valves 10, 110, 210, 310 and 410 allow the flow of unidirectional pressure gas 35 outwardly from a closed container, or container 11, to the surrounding environment. A container

"Closed" 11 means or refers to anything that contains, or may contain, a material 13 (figs. 11-12) and that is closed. The closure of the container 11 may result from the manufacturing or packaging process or when the container 11 is closed again after the removal of the material 13 from the container 11. For example, a package 11 containing coffee beans or ground coffee may return to close after the removal of a portion of the coffee beans or grounds 40 from the interior of the container 11.

[0035] The gas to be evacuated from the container 11 is contained within an inner portion 15 of the container 11 illustrated in figs. 9 and 11-12. The gas can be generated inside the container 11 after the packaging and the closure of the container 11 for example, by release of coffee, organic or other material gases 13 from inside the container.

45 closed container 11. By way of an additional example, the trapped gas may be the gas left in a container after the packing procedure. For example, a sack-type container or a type of cement or fertilizer slurry bag (not shown) could contain gas in a head space after packing and such gas could enlarge the volumetric space of the container making the package less compact and requiring more space for container storage. A pressure relief valve 10, 110, 210, 310, 410 can be used to evacuate the gas to reduce the volumetric size of the container.

[0036] Integrated particle filters of the types described herein ensure that the pressure relief valves 110, 210, 310 and 410 function properly preventing the small particle type material 12 from interfering with the closure of the valve pressure relief 110, 210, 310 and 410 after the gas has

The pressure is evacuated from the container 11. The incomplete closure of the pressure relief valves 110, 210, 310 and 410 may allow unwanted atmospheric air to enter the container 11, potentially damaging or damaging the material 13 contained in the container 11 .

[0037] Pressure relief valves 10, 110, 210, 310 and 410 can be used with any type of container

in which it is desired to evacuate the gas from such a container and the container 11 illustrated in fig. 9 is simply an example of a package that can be used with the pressure relief valves 10, 110, 210, 310 and 410. Representative examples of packages 11 include flexible, rigid cans, packages, bags and bags, all of which are known by experts in the field.

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[0038] The pressure relief valves 110, 210, 310 and 410 are preferably glued to an outer surface 17 of the container 11 on a vent 19 through the container 11 allowing the passage of gas out of the container 11 into the surrounding environment. The pressure relief valves 110, 210, 310 and 410 may be attached to any outer surface 17 of the container 11 having a vent 19 that includes, for example, a part

10, a lower part, a front part, a rear part, a side, a lid, a cover, and a cap of the container 11. Pressure relief valves 110, 210 and 310 which do not include a wetting or lubricating agent they can be used on an inner surface of the container 11.

[0039] Referring now to fig. 1, an exemplary series of four pressure relief valves 10 that are not according to the present invention is shown in fig. 1 mounted on a fragment of a liner 12 for removal and

attachment to a container, such as container 11 of fig. 9. The liner 12 carries the pressure relief valves 10 until the valves 10 are removed during the procedure of attaching the valves to the packaging as in US Patent 7,472,524 (Hoffman et al.). However, the valves 10 illustrated in fig. 1 do not require the step of injecting a lubricant, such as by applying a vacuum to separate the layers of the valve 10 to 20 allowing the dispersion of a sprayed, or preferably atomized, lubricant into the holes in the valve 10. The Valves 10 can be sized as appropriate based on the packaging application. As illustrated in fig. 1, the valves 10 are conveniently separated at regular intervals along the liner 12, for example, at an interval of one inch (2.54 cm) between the centers, although repeated spacing also depends on the packaging application.

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[0040] For use in the packaging of a product such as coffee, an opening pressure of less than 27.5 mbar (0.4 psig) and a closing pressure greater than 0.5 mbar (0.008 psig) may be desirable for the valves. In other words, the valve 10 may be designed to open when the pressure inside the container 11 exceeds the pressure external to the container by less than approximately 27.5 mbar (0.4 psig) and the valve 10 may be designed to

30 close when the pressure inside the container 11 exceeds the pressure outside the container 11 by 0.5 mbar (0.000psig) or less.

[0041] As illustrated in the exploded perspective view of fig. 2, the pressure relief valve 10 which is not according to the invention, has a bottom layer or gas impermeable base membrane 16 of

35 polyethylene terephthalate (PET), or other suitable plastic, from approximately 6.35 pm to 1.27 mm (0.25 mils to 50 mils)

[0042] thick. The selection of the general material and the construction of the valve 10 depends not only on the product that is packaged, but also on the nature of the packaging itself, particularly its flexibility or

40 stiffness The material, and particularly the thickness, of the base 16 are determined by those skilled in the art to overcome the flexural strength of the packaging. A hole or hole 18, which is best shown in fig. 2, is generally arranged centrally within the perimeter of the base 16 and extends completely through the base 16.

[0043] To mount the base 16 on the liner 12 for subsequent removal of the liner and attachment to the packaging,

apply an adhesive 20 of approximately 6.35 pm to 0.38 mm (0.25 mils to 15 mils) thick. The adhesive layer 20, which is also gas impermeable, is also provided with a hole or hole 22 conveniently aligned with the hole 18 in the base 16. Suitable adhesives for the adhesive layer 20 may include pressure sensitive and activated adhesives by heat Rubber, silicone and acrylic based adhesives can be used in the adhesive layer 20.

[0044] A corresponding hole or orifice through the liner 12 is not necessary for the valves 10 (and the pressure relief valves 110, 210, 310 and 410), but may result from the manufacturing procedure for the valve 10.

55

[0045] Cooperating with the base 16 to close and, alternatively, open the valve 10 is the flexible joint 318. The flexible joint 318 includes the layer 26, the membrane 36 with the layer 32, the adhesive layer 40, and the cover 44. Flexible joint 318, except for layer 26, flexes in response to an increase in the differential pressure of the gas to allow the gas to exit the valve 10 and flexes back to its original position to close the valve 10

when the differential pressure decreases.

[0046] Referring later to fig. 2, placed on top of base 16, around hole 18, is

a gas impermeable layer 26 of an adhesive-like material, generally referred to as a non-stick removable adhesive substrate, ultra-low tack, adherent, self-wetting, or cohesive film of approximately 6.35 pm to 0.38 mm (0, 25 mils to 15 mils) thick. As illustrated in fig. 2, a hole or hole 28 that extends through the layer of adhesive-like material 26 is also generally conveniently aligned with holes 18 and 22. A layer of silicone or other gas-impermeable dry release film 32 has a PET, or other plastic membrane, gas impermeable 36, 10 approximately 6.35 pm to 0.38 mm (0.25 mils to 15 mils) thick. An example of a silicone material that can be implemented as a release film layer 32 is polydimethylsiloxane. The membrane 36 which includes the release film layer 32 covers the holes 28, 22 and 18, with the release film layer 32 in contact with the layer of adhesive-like material 26 creating a surface attraction between the film layer 32 and the layer of material similar to an adhesive 26. By way of example only, the affinity of the release film layer 32 and the layer of material similar to an adhesive 26 can be described in quantitative terms as an adhesion force comprised between 0.098 g / cm and 3.94 g / cm (0.25 grams / inch to 10 grams / inch) when measured with a tensile test device in accordance with ASTM F-88. As best illustrated in

20 [0047] fig. 2, each of the layers 26, 32 and 36 generally extends the length (L) of the valve 10,

but it is narrower than the width (W) of the valve 10.

[0048] On the upper part of the membrane 36 and the side edges of the upper surface of the base 16 is a gas-impermeable pressure sensitive adhesive layer 40 which is approximately 6.35 pm at

25 0.38 mm (0.25 mils to 15 mils) thick. An upper or PET, or other plastic, gas-impermeable 44 membrane, approximately 6.35 pm to 0.38 mm (0.25 mils to 15 mils) thick, covers the pressure sensitive adhesive layer 40. The adhesive of layer 40 conveniently has more adhesive strength than adhesive 20 so that the bond strength between the pressure relief valve 10 and the liner 12 will be less than the bond strength between the parts or layers of the pressure relief valve 10 and so that a pressure relief valve 10 can be removed from the liner 12 without causing the valve 10 to separate. Suitable adhesives for the adhesive layer 40 may include pressure sensitive and heat activated adhesives. Rubber, silicone, and acrylic based adhesives can be used in the adhesive layer 40.

[0049] As illustrated in fig. 2, although all components 26, 32, 36, 40 and 44 generally 35 have the same extension in one direction, they are not in the transverse direction. More specifically, the layer of

material similar to an adhesive 26, the release film layer 32 and the membrane 36 are not as wide in the transverse direction as the base 16, the pressure sensitive adhesive layer 40 and the covering membrane 44. This has as result what appears in fig. 2, the flanges 46 and 10166 P 0238 EP 48 are lowered along the edges of the adhesive layer 40, and the covering membrane 44, respectively. The 40 flanges 48 prevent any lateral leakage, particularly of air into the container 11, which would be detrimental to the proper operation of the valve 10. To prevent any flexion below the layer of material similar to an adhesive 26, which it could allow the entry of air into the packaging, for the base 16 and the adhesive layer 20 materials of an appropriate thickness and flexibility are used to adapt to the package 11.

[0050] The layer of adhesive-like material 26 and the release film layer 32 may be

of the same size, that is to say having the same exterior dimensions as illustrated in fig. 2. However, in a further example, the release film layer 32 could be reduced in size to result in a lower target opening pressure and a faster closing of the valve 10 making the release layer 32 narrower than the layer of material similar to an adhesive 26. Such sizing would reduce the surface area of the layer of material similar to an adhesive 26 and the release film layer 32 in contact, thereby reducing! the energy required to separate the layers of material similar to an adhesive and release film 26, 32, thus opening! Valve 10 at a lower pressure.

[0051] Holes 18, 22 and 28 are illustrated in this example as circular. However, holes 18, 22 and 55 28 may have a different configuration, such as an oval configuration. The geometry of holes 18, 22 and

28, especially the hole 18 in the base 16, has a direct correlation with the opening pressure. The larger the perimeter of the hole 18, 22 and 28, the lower the opening pressure may be.

[0052] In operation, the base 16 and the flexible joint 318 function as follows. Membrane

36 coated with a release film 32 is separated from the layer of material similar to an adhesive 26 by the accumulation of the target opening pressure within a container, such as the container 11, to allow ventilation of the unwanted gases into the atmosphere. This pressure build-up represents a differential pressure between the pressure inside the container 11 and the atmosphere outside such container 11. The membrane 36, the pressure sensitive layer 40 and the covering membrane 44 of the flexible joint 318 all flex. together upwards under the force of the objective opening pressure to allow the gas to escape from the container 11. The upward bending movement is generally parallel, and not transverse, to the flanges 46 and 48. The gas leaves the valve 10 along the gas flow path 21 delimited by the hole 18 of the base layer 16, the sheathing coated membrane 36 adhered to the covering membrane 44 by the adhesive 40, the base layer 16 and the flanges

10 48 of the membrane 44 adhered to the base 16 by the adhesive 40. When such differential pressure is reduced, the force applied by the covering membrane 44 to the sheathing coated membrane 36 causes the membrane 36 to settle on the layer of adhesive-like material 26 closing the pressure relief valve 10.

15 [0053] After the gases are vented, and the pressure inside the container 11 falls below the

objective closing pressure, the attraction of the release film layer 32 to the layer of material similar to an ultra-low tack adhesive 26 reseals the valve 10 to provide unidirectional functionality and prevent the entry of oxygen and other atmospheric gases through of the valve 10 and inside the container 11.

20 [0054] Referring below to fig. 3, an example of pressure relief valve is shown

filtered 110 which is not according to the present invention. That is, the pressure relief valve 110 has an integrated filter 140. The filtered pressure relief valve 110 can also be mounted on a liner 12 as illustrated in fig. 1 for the valve 10 for removal and fixation to a product package 11. The portions of the valve 110 which are the same as the valve 10 are identified by the same reference numbers.

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[0055] Accordingly, as illustrated in the exploded perspective view of fig. 3, the pressure relief valve 110 has a bottom layer or base membrane 16 to which adhesive 20 is applied to mount the base 16 on the liner 12 for subsequent removal of the liner 12 and attachment to a container, such as the container 11. A hole or hole 118, as illustrated in fig. 3, is circular and is generally arranged in the center

30 within the perimeter of the base 16. The hole 118 extends entirely through the base 16. The adhesive layer 20 is also provided with a hole or circular hole 122 conveniently aligned with the hole 118 in the base 16. Both holes 118 and 122 are larger in diameter than holes 18 and 22 of valve 10.

[0056] The valve 110 has a gas impermeable intermediate layer or membrane 126, similar to the membrane

35 base 16, which can also be PET or other suitable plastic, from approximately 6.35 pm to 1.27 mm (0.25

mils to 50 mils) thick. A hole or hole 128, as illustrated in fig. 3, is generally disposed in the center within the perimeter of the intermediate membrane 126 and extends entirely through the intermediate membrane 126.

[0057] To glue the intermediate membrane 126 to the base membrane 16, an adhesive layer is applied

132 of approximately 6.35 pm to 0.38 mm (0.25 to 15 mils) thick. The adhesive layer 132 is also provided with a hole or hole 134. Both holes 128 and 134, illustrated as circular holes in fig. 3, conveniently, are generally aligned with each other and, conveniently, are generally concentric with the hole 118 in the base 16 and the hole 122 in the adhesive layer 20. The diameter of the holes is more

45 smaller than the diameter of holes 118 and 122.

[0058] A generally circular filter membrane 140 is mounted between the base 16 and the adhesive layer 132. The filter 140 has a diameter larger than the diameter of the holes 128 and 134, but smaller than the diameter of the holes 118 and 122. Accordingly, filter 140 is secured around its

50 periphery on the underside of the adhesive layer 132 under the intermediate membrane 126, and is recessed in the hole 118 of the base 16.

[0059] The filter membrane 140 may be made of a filter material suitable for packaging application with respect to gas flow and particle restriction. For example, for some coffee products,

55 a 10 gsm filter material can be used. The filter material may be a synthetic fabric, more particularly a woven nylon material. An example of a suitable material is the Cerex nylon woven material manufactured by Cerex Advanced Fabrics LP, of Cantonment, Florida, which is a particularly durable and strong material. This material has a high resistance to chemical attack, and is resistant to attack by insects and bacteria and is resistant to mold. Such filter material of filter membrane 140 prevents the entry of particulate material

Thin, such as finely ground coffee, also enters the pressure relief valve 110 and disrupts the proper functioning of the pressure relief valve 110.

[0060] Cooperating with intermediate membrane 126 to close and, alternatively, open valve 110,

5 is flexible joint 318. Flexible joint 318 includes layer 26, membrane 36 with layer 32, adhesive layer 40 and cover 44. As with valve 10, flexible joint 318, except for the layer 26, flexes in response to an increase in differential gas pressure to allow gas to exit valve 110 and flexes back to its original position to close valve 110 when the differential pressure decreases.

10 [0061] Referring then to fig. 3, placed on top of intermediate membrane 126 and around

of hole 128 is a layer 26 of an adhesive-like material. As illustrated in fig. 3, the hole or hole 28 that extends through the layer of adhesive-like material 26 is also circular of the same general diameter as holes 128 and 134 and, conveniently, is generally aligned with holes 128 and 134. Above of the layer of the layer of material similar to an adhesive 26 is the release film layer 15 32 that covers the membrane 36. The membrane 36 may be PET, or other plastic, and may have a thickness of approximately 0.25 thousand to 15 mils as described in relation to the pressure relief valve 10. The sheathing coated membrane 36 covers the holes 28, 128, 134, 118 and 122, with the shedding film layer 32 in contact with the layer of material similar to an adhesive 26 due to a surface attraction between the release film layer 32 and the material similar to an adhesive 26. There should be no side leakage, particularly air inside the package. None of the layers below the layer of material similar to an adhesive 26 should be flexed to allow air to enter the container 11; This is achieved by selecting appropriate materials and thicknesses of each of the layers to suit the packaging application.

[0062] As with valve 10, and as illustrated in fig. 3, each of layers 26, 32 and 36 is

it generally extends the length (L) of the valve 110, but is narrower than the width (W) of the valve 110, and the sheathing coated membrane 36 and the layer of material similar to an adhesive 26 are preferably narrower than the intermediate layer 126 as illustrated in fig. 3. On the upper part of the membrane 36 and the lateral edges of the upper surface of the intermediate membrane 126 is a pressure sensitive adhesive layer 40, with flanges 46, which secures the PET covering membrane, or other plastic, 44, with the flanges 48, covering the pressure sensitive adhesive layer 40. The covering membrane 44 may have a thickness of approximately 6.35 pm to 0.38 mm (0.25 mils to 15 mils) such as described for the pressure relief valve 10.

[0063] Holes 28, 118, 122, 128 and 134 are described and illustrated in this example as circular. Without

However, they may have a different configuration, such as an oval configuration. The valve 110 works in the same way as the valve 10, with the additional function of blocking the passage of small product particles, such as ground coffee, within the valve 110 beyond the base 16. As with the valve 10, an increase in differential pressure within the container 11 causes the flexible joint 318 to move by separating the membrane 36 from 40 the layer similar to an adhesive 26 in the intermediate membrane 126. The separation of the membrane 36 from the layer similar to An adhesive 26 opens the valve 110 allowing the gas to flow through the gas flow path 21 in the direction of the indicator arrows and out of the valve 110.

[0064] The obstruction of the particles by the filter membrane 140 prevents such particles from being lodged

45 between the membrane 36 and the adhesive-like layer 26 in the intermediate membrane 126. The accumulation of particles could potentially prevent the complete surface-to-surface settlement of the membrane 36 on the similar adhesive layer 26 leaving passages between and the layer similar to an adhesive 26 through which air could enter the container 11 through the pressure relief valve 110.

50 [0065] Referring to continuation to fig. 4, an additional example is illustrated which is not according to the

present invention. A pressure relief valve 210 of this example can also be mounted on a liner 12 for removal and attachment to the product package 11 as illustrated in fig. 1 for valve 10. Portions of valve 210 that are the same as valve 10 are identified by the same reference numbers.

[0066] Accordingly, as illustrated in the exploded perspective view of fig. 4, the

pressure relief valve 210 has a bottom layer or base membrane 16 with a hole or orifice 18 generally disposed in the center within the perimeter of the base 16 and extending through the thickness of the base 16. To mount the base 16 on the liner 12 for subsequent removal of the liner and attachment to the packaging, an adhesive 20 is applied. The adhesive layer 20 is also provided with a conveniently aligned hole or hole 22

with hole 18 in base 16.

[0067] The valve 210 has a gas impermeable intermediate layer or membrane 226, similar to the base membrane 16, which can also be, for example, PET or other suitable plastic, of approximately 6.35 pm at

5 1.27 mm (0.25 mils to 50 mils) thick.

[0068] A hole or hole 228, as illustrated in fig. 3, is generally arranged in the center within the perimeter of the intermediate membrane 226 and extends completely through the intermediate membrane 226. Between the intermediate membrane 226 and the base membrane 16 are two layers of adhesive impervious to the

10 separate gas 232 about 6.35 pm to 0.38 mm (0.25 mils to 15 mils) thick. Each layer of adhesive 232 is provided with a hole or hole 234. As illustrated in fig. 4, holes 18, 22, 28, 228 and 234 are circular and, conveniently, are generally aligned with each other.

[0069] A filter membrane 240, which can have the same extension as the base 16, the intermediate membrane 226 and the adhesive layers 232, is mounted between the base 16 and the intermediate membrane 226, more

particularly between the layers of adhesive 232. In a variation, the filter 240 may be made of a material such as polyethylene, polyester or polypropylene, provided with a plurality of holes drilled by laser or punched 242, in the area of the holes 234, 228, 28, 18 and 22, of an appropriate number and size for the application of packaging with respect to gas flow and particle restriction.

twenty

[0070] In another variation, the filter membrane 240 may, without holes 242, be impervious to liquid while allowing unwanted gases to escape from the packaging. Such a filter material could be an expanded polytetrafluoroethylene (ePTFE), breathable liquid-proof fabric, or some other hydrophobic or oleophobic material that prevents the passage of an undesirable liquid to the outside or inside the container 11, and prevents

Consequently, the functioning disorder of the pressure relief valve 210 is disrupted.

[0071] Cooperating with the intermediate membrane 226 to close and, alternatively, open the valve 210 is the flexible seal 318. The flexible seal 318 of the valve 210 includes the layer 26, the membrane 36 with the layer 32, the adhesive layer 40 and cover 44. As with valves 10, 110, flexible joint 318, except the layer

30 26, flexes in response to an increase in differential gas pressure to allow gas to exit valve 210 and flexes back to its original position to close valve 210 when the differential pressure decreases.

[0072] Placed on top of the intermediate membrane 226, around the hole 228, is the layer 26 of an adhesive-like material with the hole or hole 28 extending through the layer of material similar to a

adhesive 26 as described in relation to pressure relief valves 10 and 110. Above the layer of the layer of material similar to an adhesive 26 is a membrane 36 with a layer of release film 32 as described in relationship with the pressure relief valves 10 and 110. The membrane 36 may be made of PET or other plastic material. An example of a silicone material that can be implemented as the release film layer 32 is polydimethylsiloxane. The sheathing coated membrane 36 covers the holes 28, 228, 234, 18 and 22 by virtue of the surface attraction between the shedding film layer 32 and the layer of adhesive-like material 26. As in the valve 10 and as illustrated in fig. 4, each of the layers 26, 32 and 36 generally extends along the length (L) of the valve 110, but is narrower than the width (W) of the valve 210, and the sheathing coated membrane 36 and 45 the layer of material similar to an adhesive 26 are preferably narrower than the intermediate layer 226.

[0073] On the upper part of the sheathing coated membrane 36 and the lateral edges of the upper surface of the intermediate membrane 226 is a layer of pressure-sensitive adhesive 40 that secures the covering membrane of PET, or other plastic 44 , with flanges 48, covering the layer of sensitive adhesive to

50 the pressure 40. The holes 18, 22, 28, 228 and 234 are described and illustrated in this example as circular. However, they may have a different configuration, such as an oval configuration.

[0074] Pressure relief valve 210 is similar in operation to pressure relief valve 10, with the additional function of blocking the passage of particles or liquid, depending on the membrane material of

55 filter 240. As with the valve 10 and the valve 110, an increase in the differential pressure inside the container 11 causes the flexible joint 318 to move separating the membrane 36 from the layer similar to an adhesive 26 in the intermediate membrane 226. The separation of the membrane 36 from the adhesive-like layer 26 opens the valve 210 allowing the gas to flow through the gas flow path 21 in the direction of the indicating arrows and out of the valve 210. The valve of pressure relief 210 is also similar to the valve

pressure relief 110, particularly with respect to the obstruction of particles by the filter membrane 240.

[0075] Reference will now be made to figs. 5-14, which show embodiments and additional examples of unidirectional pressure relief valves having an integrated filter 310, 410. The pressure relief valve

5 310 illustrated in fig. 5 is an oil-free valve according to the present invention that does not require the use of a wetting agent, such as a silicone or graphite impregnated oil, to facilitate complete closure of the pressure relief valve 310. The relief valve of pressure 410 illustrated in figs. 9-14 is not according to the present invention and preferably uses a wetting agent to moisten the relevant valve surfaces to facilitate the total closure of the pressure relief valve 410.

10

[0076] As discussed in more detail below, the pressure relief valves 310, 410 are implemented so that the integrated filter: (1) provides a support base and a point of attachment to the container for the valve pressure relief 310, 410; and (2) provides part of the valve structure that regulates the flow of unidirectional gas through pressure relief valves 310, 410. An important advantage of such a structure

15 is that the pressure relief valves 310, 410 can be manufactured more compact and may be provided with a lower profile than the valves that do not include the novel configuration. This is of great importance in packaging applications that require that pressure relief valves 310, 410 go unnoticed and do not detract, or interfere with, the design elements of the container 11. On the other hand, the relief valve embodiments of pressure 310, 410 illustrate that the principles described in this document can be applied to valves

20 both oil-free and wetted that provide the manufacturer with a range of product options to best meet customer needs.

[0077] Pressure relief valves 310, 410 share many of the same components with pressure relief valves 10, 110 and 210. For simplicity and brevity, the same reference numbers are used

25 to identify the same components throughout the figures and in the text description of the different embodiments.

[0078] Referring again to fig. 5, the oil-free pressure relief valve 310 illustrated therein includes an integrated particle filter component comprising a base filter layer 316 in

30 in combination with a flexible gasket 318. Together, the base filter layer 316 and the flexible gasket 318 regulate the flow of unidirectional gas through the pressure relief valve 310. The filter layer 316 is a type of layer of base because, in this embodiment, the filter layer 316 provides a platform on which the pressure relief valve 310 is constructed and fixed directly to the container 11.

[0079] Referring again to fig. 5, the filter layer 316 includes a periphery 320, a first

side 322 and a second side 324. In relation to the parts comprising the pressure relief valve 310, the first side 322 can be considered an inner side while the second side 324 can be considered an outer side. The first and second sides 322, 324 define a body 326 between the sides 322, 324. In the example, the filter layer 316 is generally smooth, or flat, and is made of a strip-like material. materials

Representative representatives suitable for use in the manufacture of filter layer 316 may include polyethylene, polypropylene, pEt, or other suitable plastic material. The filter layer 316 preferably has a thickness between approximately 6.35 pm and 1.27 mm (0.25 mils and 50 mils) depending on the application.

[0080] In certain "green" applications in which environmentally friendly materials are required

However, it may be desirable that the pressure relief valve 310 is constructed of biodegradable materials,

that is materials that will decompose when they are in a landfill. When biodegradability is desired, the filter layer 316 and other components (for example, cover membrane 44 and membrane 36) of pressure relief valve 310 may be made of polylactic acid, cellulose acetate or other materials suitable for composting

fifty

[0081] Referring to figs. 5, 6 and 6A, the exemplary filter layer 316 includes a filter element 328. The filter element 328 provides the passage of gas through the body 326. Although the filter element 328 allows gas to pass through the body 326 , it also obstructs the passage of small particulate matter from the interior of the container 11 through the body 326. The exemplary filter layer 316 defines the opening portions 330 and

Barrier 552 33. In the example, barrier portions 332 are all parts of filter layer 316 that are not opening portions 330. Barrier portions 332 are preferably continuous gas impervious portions of second side 324 of the filter layer 316 serving as a barrier to the movement of any substance through the body 326.

[0082] Referring to figs. 6 and 6A, the opening portions 330 of the filter layer 316 are preferably holes entirely through the body 326 of the filter layer 316 that provide the passage of gas completely through the body 326. The opening portions 330 consist of Small plural holes. To avoid clouding the drawings, only several such small holes are indicated by reference number 330

5 in fig. 6A. The opening portions 330 may comprise a plurality of laser perforated or die-cut holes of an appropriate number and size for the packaging application given the requirements for gas flow and particle filtration. In the embodiment, the filter element 328 acts as a type of "sieve" that selectively allows the movement of gas through the body 326, but blocks the passage of matter in small particles, keeping that matter in particles throughout the second side 324 of the filter layer 316 and out of 10 the pressure relief valve 310.

[0083] Preferably, the opening portions 330 of the filter element have a mesh size between about 30 mesh to about 200 mesh. As is known, a mesh size 30 would block particles having a particle size greater than about 595 pm while a size of

15 mesh 200 will block particles having a particle size greater than about 74 pm. As illustrated in figs. 5, 6 and 6A, the opening portions 330 may be of a generally round shape when viewed directly from above or below as in these figures. By way of example only, round-type openings 330 that could be used in a pressure relief valve 310 suitable for use in a ground coffee container 11 could have a diameter of approximately 0.254 mm (0.010 inches), or approximately 20 mesh No. 50. As is also known, the No. 50 mesh will block particles larger than about 297 pm, which is a typical size of the small particle matter found in a ground coffee container 11.

[0084] As illustrated in figs. 7, 7A, 8 and 8A, within the scope of the invention, many variations of the filter layer 316 are provided. For example, the opening portions 330 defined by the element of

filter 316 could include small holes that have a shape when viewed directly from above or from below (ie, the plan view) constituted by pins 330a in the embodiment of filter element 316a (figs. 7-7A), or slits in the form of x 330b in the embodiment of the filter element 316b (figs. 8-8A). The opening portions 330 could have other shapes such as rectangles. Combinations of all these 30 forms of opening portion 330 may be used.

[0085] As illustrated in figs. 5-8A, the opening portions 330, 330a, 330b defined by the filter element 328 may be grouped and arranged in one or more groupings 333. The organization of the opening portions 330 in a group 333 is useful for placing the portions opening 330 over the

35 vent 19 to maximize the volumetric flow of gas exiting through vent 19 and the pressure relief valve 310 to the environment.

[0086] The grouping 333 may have a width dimension (W) and a length dimension (L) in the width and length dimensions illustrated in figs. 5 and 10. In the examples of figs. 5-8A, the dimension of

The width (W) of the cluster 333 is approximately the same as the length dimension of the cluster (L) which provides a compact path for the flow of gas through the filter layer 316.

[0087] The dimensioning of the opening portions 330 and / or the amount and location of the clusters 333 can be modified to increase or decrease the gas flow through the pressure relief valve 310

45 as desired for a given application.

[0088] In a further embodiment, the filter layer 316 could be a liquid impermeable membrane. Such an embodiment of the filter layer 316 could be impervious to the liquid while allowing the passage of gas through it. The opening portions 330 may, or may not, be present in such a filter layer 316. The

The material used to construct such a liquid impervious filter layer 316 could include those described above in relation to the filter layer 240 of the pressure relief valve 240 (fig. 4).

[0089] Referring again to fig. 5, the adhesive layer 20 is provided on the second side 324 of the filter layer 316 both to extractablely mount the filter layer 316 in the release liner 12

55 to permanently fix the filter layer 316 and the pressure relief valve 310 to a container 11. In the example, the adhesive layer 20 can be from about 6.35 pm to 0.38 mm (0.25 mils to 15 mils) thick. The adhesive layer 20 should be impervious to gas flow to prevent the escape of gas between the filter layer 316 and the outer surface 17 of the container 11. Suitable adhesives for the adhesive layer 20 may include pressure sensitive and activated adhesives by heat Rubber, silicone and rubber based adhesives can be used

acrylics in the adhesive layer 20.

[0090] Referring again to fig. 5, the adhesive layer 20 is provided with a hole 22 to space the adhesive layer 20 of the opening portions 330 of the filter element 328. The spacing of the layer

5 of adhesive 20 of opening portions 330 may prevent clogging of opening portions 330, which may be desirable in some applications.

[0091] In other examples such as those described below in relation to fig. 10, the adhesive layer 20 could be deposited entirely through the second side 324 of the filter layer 316 and the portions

10 of opening 330 could be formed simultaneously with the openings 22a in the adhesive layer 20. In such an example, laser perforation or die cutting of many opening portions 330 in the filter layer 316 simultaneously form many corresponding openings 22a through the adhesive layer 20 aligned with the opening portions 330 as illustrated for the pressure relief valve 410 in fig. 10. The gas will pass it through the openings 22a and the opening portions 330 as the gas flows through the relief valve 15 of pressure 310. Such a layer of adhesive 20 with openings 22a close to the opening portions 330 it could serve to trap the particles adhered to the adhesive layer 20 preventing such particles from reaching the filter element 328.

[0092] Referring again to fig. 5, as with the pressure relief valves 10, 110 and 20 210, the components, comprising flexible joint 318, provide a type of "gate" or "closure" that

it allows pressure relief valves 10, 110, 210 and 310 to be placed in a closed state and, alternatively, in an open state. In the closed state, the flexible joint 318 is in a first position and the pressure relief valves 10, 110, 210 and 310 are sealed blocking the air inlet to the pressure relief valve 10, 110, 210 and 310 and the container 11. In the open state, the flexible joint 318 is in an additional position 25 in which the pressure relief valves 10, 110, 210 and 310 allow the flow of unidirectional gas from the container 11, through the pressure relief valve 10, 110, 210 and 310 along the gas flow path 21 and outward to the environment. Figs. 11-14 illustrate the closed (fig. 11) and open (figs. 12-14) states of the pressure relief valve 410 which are generally representative of the operation of the pressure relief valves 10, 110, 210 and 310 .

30

[0093] As with the pressure relief valves 10, 110, 210, the pressure relief valve 310 opens and closes based on the pressure differential between the pressure inside the container 11 and the pressure outside the container 11. The pressure relief valve 310 may be designed to open with any desired target pressure differential. Only by way of example, the pressure relief valve can be designed to

35 have an objective opening pressure when the pressure inside the container 11 exceeds the external pressure to the container 11 by less than about 27.5 mbar (0.4 psig). The pressure relief valve 310 may be designed to close when the pressure inside the container 11 exceeds the pressure outside the container 11 by 0.5 mbar (0.008 psig) or less. Other objective opening and closing pressures can be used and the foregoing are simply non-restrictive examples.

40

[0094] As illustrated in fig. 5, the flexible joint 318 comprises the layer of material similar to an adhesive 26, the membrane 36 with the release film layer 32 applied thereto, the covering membrane 44 and an adhesive layer 40 joining the membrane, or flexible covering layer 44, to the membrane 36 and selectively joining the flanges 48 of the covering membrane 44 (i.e., the outer areas of the

45 cover membrane 44 in the example) to the fixing zones 334, 336 of the filter layer 316. As used herein, "selective bonding" means or refers to the joint of the covering membrane 44 alone. to the fixing zones 334, 336 of the filter layer 316 and not to the filter layer 316 between the fixing zones 334, 336. Because the covering membrane 44 is not joining the filter layer 316 between the fixing zones 334, 336, the cover membrane 44 is allowed to flex and move away from the filter layer 316 (for example, see 50

[0095] fig. 12) along unbound areas when in the open state to allow gas to escape from the pressure relief valve. Accordingly, the cover membrane 44 of the example is a type of flexible cover membrane 44.

[0096] The gas flow path 21 indicated by the arrows in fig. 5 extends through the portions of

opening 330 and is delimited by the sheathing coated membrane 36 (adhered to the covering membrane 44 by the adhesive 40 in the example), the filter layer 316 and the flanges 48 of the covering membrane 44 selectively bonded to the membrane of filter 316 through the adhesive 40 along the fixing areas 334, 336. The gas flow path 21 allows the gas to move through the pressure relief valve 310.

[0097] Referring once again to fig. 5, placed on top of the filter layer 316 and through the filter element 328 is the gas impermeable layer 26 of a material similar to an adhesive of the same type described in relation to the pressure relief valves 10, 110 and 210. Such a layer of material similar to an adhesive 26

5 is generally referred to as a non-stick, ultra-low tack, adherent, self-wetting, removable adhesive, or cohesive substrate.

[0098] The layer of material similar to an adhesive 26 preferably has a thickness of about 6.35 pm to 0.38 mm (0.25 mils to 15 mils). The layer of material similar to an adhesive 26 may also include a

10 orifice 28 extending around the filter element 328 and aligned with the filter element 328 and the opening holes 330 and the hole 22.

[0099] In the example, the gas impermeable membrane 36, made of PET or other plastic material, is coated with a gas impermeable silicone, or another layer of dry release film 32. An example 10

15 of a silicone material that can be implemented as the release film layer 32 is polydimethylsiloxane. The membrane 36 preferably has a thickness of about 6.35 pm to 0.38 mm (0.25 mils to 15 mils). The membrane 36 covers the hole 28 in the layer of material similar to an adhesive 26 and covers the filter element 328 with the release film layer 32 in contact with the layer of material similar to an adhesive 26 creating a surface attraction between the film layer 32 and the layer of an adhesive-like material 26 and the membrane sitting tightly against the layer of an adhesive-like material 26 blocking the movement of gas through the filter element 328. Although the release film layer 32 and the layer of adhesive-like material 26 are seated closely together to close the pressure relief valve 310, they are not joined because they can be separated from each other when the pressure differs inside the container 11 exceeds the target pressure and the Flexible joint 318, except the layer of similar material 25 to an adhesive 26, moves to the additional position to open the pressure relief valve 310.

[0100] The layer of material similar to an adhesive 26 comprises a material with an affinity for the release film layer 32. Only by way of example, the affinity of the layer of material similar to an adhesive 26 for the film layer of detachment 32 can be described in quantitative terms as a

Adhesion strength between 0.098 g / cm and 3.94 g / cm (0.25 grams / inch and 10 grams / inch) when measured with a tensile test device in accordance with ASTM F-88. With the appropriate selection of materials and surface energies inherent in the material similar to an adhesive 26 and the release film layer 32, the ability to form joints of controlled adhesion force is established. The affinity of the layer of material similar to an adhesive 26 by the release film layer 32 provides a means to hold the membrane 36 in place against the filter element 328, and to achieve a gas-tight gasket that allows the Valve 310 function as a one-way pressure relief valve.

[0101] As illustrated in fig. 5, each of layers 26, 32 and 36 generally extends through the length (L) of the pressure relief valve 310, but is generally narrower than the width (W) of the

40 pressure relief valve 310; the membrane 36 and the layer of adhesive-like material 26 are located between the flanges 48 in the example, which prevents the covering membrane 44 between the flanges 48 from joining the filter layer 316 by the adhesive 40. This , in turn, allows the cover membrane 44 to flex to open the pressure relief valve 310.

[0102] On the membrane 36 and the fixing areas 334, 336 of the first side 322 of the filter layer 316

this is a layer of gas-sensitive pressure sensitive adhesive 40 that can be approximately 6.35 pm to 0.38 mm (0.25 mils to 15 mils)

[0103] thick. The adhesive layer 40 may be of the same adhesive used for the adhesive layer 20. 50

[0104] The cover membrane 44 is selectively bonded to the fixing zones 334, 336 of the filter layer 316 by the adhesive layer 40 as described above. The cover membrane 44 can be selectively bonded to the filter layer 316 by means other than the adhesive layer 40. For example, the cover membrane 44 could be selectively attached to the filter layer 316 by means of sonic welding.

55 The cover membrane 44 may be of gas impermeable PET or other flexible plastic material. The cover membrane 44 may have a thickness of approximately 6.35 pm to 1.27 mm (0.25 mils to 50 mils).

[0105] The layer of material similar to an adhesive 26 and the release film layer 32 may have the same length and width dimensions. As with the other valve embodiments, the layer of

release film 32 could be sized to result in a lower objective opening pressure and a faster closing of the valve 10 by making the release layer 32 narrower than the layer of material similar to an adhesive 26. Such dimensioning would reduce the surface area of the layer of material similar to an adhesive 26 and the release film layer 32 in contact, thereby reducing the energy needed to separate the layers of material similar to an adhesive and release film 26, 32 allowing that the pressure relief valve 310 opens at a lower pressure.

[0106] Fig. 5 shows that holes 22 and 28 are circular. However, holes 22 and 28 may have a different configuration, such as an oval configuration. The geometry of holes 22 and 28 has a

10 direct correlation with the target opening pressure. The larger the area of each hole 22 and 28, the lower the target pressure necessary to put the pressure relief valve 310 in the open state.

[0107] In operation, the pressure relief valve 310 is initially in a closed state similar to that shown in fig. 11 for the pressure relief valve 410 which is not according to the invention. Coated membrane

15 36 of release film 32 is seated against the layer of material similar to an adhesive 26 and is preferably held in place by surface affinity between the materials comprising the coated membrane 36 of release film 32 and the layer of material similar to an adhesive 26. A wetting agent is not required to form a complete gas impervious gasket between the membrane 36 and the layer of material similar to an adhesive 26 because the surface affinity is sufficient to keep the pressure relief valve in a state 20 closed. The membrane 36 blocks the movement of the gas through the filter element 328 preventing the gas inside the container 11 from escaping into the atmosphere and preventing air from entering the container 11 while retaining the freshness of the material 13 inside the container 11.

[0108] When the pressure inside the container 11 exceeds the target pressure required to open the pressure relief valve 310, both the cover membrane 44 and the flexible seal membrane 318 secured to the

cover membrane 44 by means of the adhesive layer 40 are flexed outwardly together under the force of the objective opening pressure similar to that illustrated in figs. 12-14 for pressure relief valve 410.

[0109] The flexion of the covering membrane 44 and the membrane 36 spaces the membrane 36 of the layer of material similar to an adhesive 26. The flexion of the covering membrane 44 loads on the covering membrane

44 in the same way that a spring is loaded. The flexion of the covering membrane 44 opens the gas flow path 21 indicated by the arrows in fig. 5 allowing as! that the gas escapes from the container 11 and putting the pressure relief valve 310 in the open state.

[0110] The pressure differential required to open the pressure relief valve 310 can be created by

various means, including by releasing coffee gases from the interior of container 11 or by force applied externally against container 11. For example, packages containing a product such as cement slurry or fertilizer can be pressed by adjacent containers when loaded in a pale or when stored. If a pressure relief valve 310 was incorporated into the container, the force applied would be generated by a pressure differential within the container causing the gas inside the outlet to flow through the pressure relief valve 310 advantageously reducing the volumetric size of the container by making easier and more efficient to store or transport the container.

[0111] When the differential pressure is reduced below the target pressure, the cover membrane 45 44 of the flexible joint 318 applies a force as it discharges and returns to its original position. The force

causes the membrane 36 to settle back on the adhesive-like material 26 by closing the filter element 328 and returning the pressure relief valve 310 to its closed state. The procedure of opening the pressure relief valve 310 is repeated when the differential pressure inside the container 11 again exceeds the target opening pressure.

fifty

[0112] The operation of the pressure relief valve 310 is improved by the integrated filter layer 316. The filter layer 316 and the filter element 328 advantageously prevent small particulate matter from inside the container 11 from entering the pressure relief valve 310 and lodge between the membrane 36 and the layer of material similar to an adhesive 26. Such accumulation of particulate matter could create unwanted passages between

55 the membrane 36 and the layer of adhesive-like material 26 that could allow air to enter the container 11 through the pressure relief valve 310. The filter element 328, therefore, ensures complete closure of the pressure relief valve 310 when in the closed state preventing the infiltration of air into the container 11 potentially damaging the contents of the container 11.

[0113] The integration of the filter element 328 with the filter layer 316 and the exemplary selective union of the covering membrane 44 to the filter layer 316 provides an opportunity to build a more compact and profile pressure relief valve 310 low. A more compact and low profile pressure relief valve provides opportunities for the pressure relief valve 310 to go more unnoticed when it is attached

5 to container 11. This is particularly important when a pressure relief valve is glued to an outer surface 17 of container 11.

[0114] Referring now to figs. 9-14, the pressure relief valve 410 illustrated therein is not according to the invention and preferably uses a wetting agent 338 to moisten the surfaces of the

10 filter layer 316 and flexible seal 318 to facilitate the total closure of the pressure relief valve 410. As with the pressure relief valve 310, the pressure relief valve 4109 can be advantageously constructed to be Compact and have an extremely low profile. These advantages are possible because, in the example, the integrated filter layer 316 allows both fixing to a container and providing support for the pressure relief valve 410, thus eliminating! any need for the pressure relief valve 410 to include additional layers of material.

[0115] Referring to figs. 10-12, the pressure relief valve 410 illustrated therein includes a base filter layer 316 in combination with a flexible gasket 318. As with the pressure relief valve 310 (and the valves 10, 110 and 210), filter layer 316 and flexible seal 318 regulate gas flow

Unidirectional 20 through the pressure relief valve 410. The filter layer 316 provides a platform on which the pressure relief valve 310 is constructed and is fixed directly to the container 11 by the adhesive layer 20. Referring again to figs. 10-12, the filter layer 316 includes a periphery 320, first and second sides 322, 324 and a body 326 between the sides 322, 324. The filter layer 316 is generally smooth, or flat, and may be made of polyethylene. , polypropylene, PET, biodegradable polylactic acid and cellulose acetate, or any other suitable material or materials. The filter layer 316 preferably has a thickness between approximately 6.35 pm and 1.27 mm (0.25 mils and 50 mils) depending on the application.

[0116] Exemplary filter layer 316 includes a filter element 328 with opening and barrier portions 330, 332 to provide a passage of gas entirely through the body 326 through the portions of

30 opening 330 while the barrier portions 332 prevent small particulate matter and other objects inside the container 11 from passing through the body 326 and interfering with the operation of the pressure relief valve 410 as described in relation to with the pressure relief valve 310 and the description of the filter layer 316 of the pressure relief valve 310 is incorporated herein by reference with respect to the pressure relief valve 410. Barrier portions 332 are preferably Continuous, gas-impermeable portions of the second side 324 of the filter layer 316 serving as a barrier to the movement of any substance through the body 326.

[0117] The opening portions 330 of the filter element 328 preferably consist of small plural holes that can be formed in the filter layer 316 by laser perforation, die cutting, or any

40 suitable procedure and can be sized and arranged based on requirements of gas flow and particle filtration. As with the pressure relief valve 310, the filter element 328 acts as a type of "sieve" that can have a mesh size of between about 30 mesh to about 200 mesh. The opening portions 330 can have the same shapes and sizes and may be arranged in one or more groups 333 as described in relation to the pressure relief valve 310 and as illustrated in Figs. 6, 6A, 7, 7A, 8 and 8A and the description of such opening portions 330 and clusters 333 is incorporated herein by reference with respect to pressure relief valve 410. Sizing of opening portions 330 and / or the amount and location of the clusters 333 may be modified to increase or decrease the gas flow through the pressure relief valve 410 as desired for a given application.

[0118] Also as described in connection with the pressure relief valve 310, the filter layer 316

it could be a membrane impervious to liquid impervious to liquid while allowing the passage of gas through it.

[0119] Referring again to figs. 10-12, the adhesive layer 20 is provided in the second

55 side 324 of the filter layer 316 to removably mount the filter layer 316 in the detachment liner 12 and permanently fix the filter layer 316 and the pressure relief valve 310 to a container 11. In the example, The adhesive layer 20 can be approximately 6.35 pm to 0.38 mm (0.25 mils to 15 mils) thick. The adhesive layer 20 should be impermeable to gas flow to prevent the escape of gas between the filter layer 316 and the outer surface 17 of the container 11. Suitable adhesives for the adhesive layer 20

they can include pressure sensitive and heat activated adhesives. In the adhesive layer 20 rubber, silicone and acrylic based adhesives can be used.

[0120] Referring again to figs. 10-12, the adhesive layer 20 is deposited entirely through the second side 324 of the filter layer 316 and the opening portions 330 could be formed

simultaneously with the openings 22a in the adhesive layer 20 since the opening portions 330 are formed by laser drilling, die cutting or by other appropriate means. Such an adhesive layer 20 close to the opening portions 330 could serve to trap the particles adhered thereto, for example inside the openings 22a, preventing such particles from reaching the filter element 328.

10

[0121] Referring now to figs. 10-14, the components, comprising the flexible joint 318, of the pressure relief valve 410 provide a type of "gate" or "closure" that allows the pressure relief valves 410 to be placed in a closed state and, alternatively, in an open state as described in relation to the pressure relief valves 10, 110, 210 and 310. In the closed state, the flexible joint

15 318 is in a first position and the pressure relief valve 410 is sealed by blocking the air inlet to the pressure relief valve 410 and the container 11. In the open state, the flexible joint 318 is in an additional position in which the pressure relief valve 410 allows the flow of unidirectional gas from the container 11, through the gas flow path 21 and outward to the surroundings. Figs. 11-14 illustrate the closed (fig. 11) and open (figs. 12-14) states of the pressure relief valve 410.

twenty

[0122] Pressure relief valve 410 opens and closes based on the pressure differential between the pressure inside the container 11 and the pressure outside the container 11. The pressure relief valve 410 may be designed to open with any desired target pressure differential. A target pressure differential may be less than about 0.4 psig greater than the pressure inside the container 11 than outside the

25 container 11 while the pressure relief valve 410 may be designed to close when the pressure inside the container 11 exceeds the pressure outside the container 11 by 0.008 psig or less. As with pressure relief valves 10, 110, 210 and 310, other objective opening and closing pressures can be used and the foregoing are simply non-restrictive examples.

30 [0123] Referring to the exploded view of fig. 10, flexible joint 318 has a

structure that can be moistened with a moisturizing fluid 338 to obtain optimum adhesion between the strip, or closure 340, and the filter layer 316. In the example, flexible joint 318 includes closure 340 (also referred to in the industry as "strip dry ”or simply“ strip ”), the flexible covering membrane 44, and an adhesive layer 40 that joins the covering membrane 44, or layer, to the closure 340 and selectively joining the flanges 48 of the

35 cover membrane 33 (the outer areas of the cover membrane 44 in the example) to the fixing zones 334, 336 of the filter layer 316. As described above, "selective bonding" means or refers to the union of the covering membrane 44 only to the fixing areas 334, 336 of the filter layer 316 and not to the filter layer 316 between the fixing areas 334, 336. Because the covering membrane 44 is not joined to the filter layer 316 where the closure 340 is secured to the covering membrane 44 between the fixing areas

40 334, 336, the cover membrane 44 is allowed to flex and move away from the filter layer 316 as illustrated in figs. 12-14 along unbound areas when in the open state to allow gas to escape from the pressure relief valve. When the unbound portion of the cover membrane 44 moves away from the filter layer 316, the closure 340 also moves at least partially away from the filter layer 316. Accordingly, the cover membrane 44 of the example is a type of membrane, or layer, of flexible coverage 44.

Four. Five

[0124] In the examples, the gas flow path 21 is delimited by the closure 340 (adhered to the covering membrane 44 by the adhesive 40 in the example), the filter layer 316 and the flanges 48 of the membrane cover 44 selectively attached to the filter membrane 316 by the adhesive 40 along the fixing areas 334, 336. The exemplary gas flow path 21 allows the gas to travel through the relief valve of

50 press 310 as described in this document.

[0125] As illustrated in fig. 10, the closure 340 generally extends through the length (L) of the pressure relief valve 410, but is generally narrower than the width (W) of the pressure relief valve 410; the closure 340 is located between the flanges 48 in the example, which prevents the membrane from

55 cover 44 between flanges 48 adheres to filter layer 316 by adhesive 40. This, in turn, allows cover membrane 44 to flex to open the pressure relief valve.

[0126] The closure 340 is secured to the covering membrane 44 by the adhesive layer 40. The closure 340 prevents the adhesive 40 from making contact with the filter layer 416 where it is not joined with the covering membrane

between the fixing zones 335 and 336. The adhesive layer 40 joins the covering membrane 44 to the fixing zones 334, 336 of the filter layer 316. The adhesive layer 40 is a waterproof pressure sensitive adhesive layer to gas 40 which can be approximately 6.35 pm to 0.38 mm (0.25 mils to 15 mils) thick.

5 [0127] The adhesive layer 40 may be of the same adhesive used for the adhesive layer 20.

[0128] The cover membrane 44 can be selectively joined to the filter layer 316 by means other than the adhesive layer 40. For example, the cover membrane 44 could be selectively joined to the filter layer 316 by means of sonic welding. The cover membrane 44 may be gas impermeable PET or

10 other flexible plastic material. The cover membrane 44 may have a thickness of approximately 6.35 pm to 1.27 mm (0.25 mils to 50 mils).

[0129] Referring to figs. 10-14, the optional rails 342, 344 may be attached to the cover membrane 44 by an adhesive 346. If provided, the rails 342, 344 are useful for

15 provide separation between the unbound portion of the cover membrane 44 and any adjacent object so that the pressure relief valve 410 can freely move away from the filter layer 316 to function properly. Adhesive 346 may be of the same material as adhesives 20 and 40.

[0130] In operation, the pressure relief valve 410 is initially in a closed state. The closure 20 340 is seated against the filter layer 316 through the opening and barrier portions 330, 332 closing

the opening portions 330 and preventing the flow of gas through them while retaining the freshness of the material 13 inside the container 11.

[0131] The wetting agent 338 is preferably provided between the filter layer 316 and the closure 340. The wetting agent 338 may comprise, for example, a lubricating oil impregnated with silicone or graphite. He

Wetting agent 338 can be sprayed, or preferably atomized, into opening portions 330 during manufacturing or during application to container 11. Wetting agent 338 improves surface adhesion between first side 322 of filter layer 316 and the seal 340 improving the formation of a gas tight seal when the pressure relief valve 410 is in the closed state.

30

[0132] Referring to figs. 12-14, when the pressure inside the container 11 exceeds the target pressure required to open the pressure relief valve 410, both the cover membrane 44 and the closure 340 secured to the cover membrane 44 by the adhesive layer 40 are they flex together outward under the force of the objective opening pressure.

35

[0133] Referring again to figs. 12-14, the flexion of the covering membrane 44 and the closure 340 spaces the membrane closure 340 of the filter layer 316 and the filter element 328. The flexion of the covering membrane 44 loads the covering membrane 33 of the same way a spring is loaded. The flexion of the covering membrane 44 opens the gas flow path 21 indicated by the arrows 21 allowing

40 ace! that the gas escapes from the container 11 and putting the pressure relief valve 410 in the open state.

[0134] As described in connection with the pressure relief valve 310, the pressure differential required to open the pressure relief valve 410 can be created by various means, including by release of coffee gases or other material 13 from the inside the container 11 or by force applied externally against the

45 container 11. The pressure relief valve 410 allows the unidirectional gas flow out of the container 11 to evacuate such gas or reduce the volumetric size of the container 11 to facilitate storage or transport of the container.

[0135] When the differential pressure is reduced below the target pressure, the cover membrane 50 44 of the flexible joint 318 applies a force as it discharges and returns to its original position. The force

causes the closure 340 to re-settle in the filter layer on the filter element and the opening and barrier portions 330, 332 by returning the pressure relief valve 410 to the closed state. The procedure of opening the pressure relief valve 410 is repeated when the differential pressure inside the container 11 again exceeds the target opening pressure.

55

[0136] As with the pressure relief valve 310, and the pressure relief valves 110 and 210, the operation of the pressure relief valve 410 is improved by the integrated filter layer 316. The filter layer 316 and the filter element 328 advantageously prevent the small particulate matter 13 from inside the container 11 from entering the pressure relief valve 410 and being lodged between the filter layer 316 and the closure 340. Such

accumulation of particulate matter 13 could create unwanted passages between the filter layer 316 and the closure 340 that could allow air to enter the container 11 through the pressure relief valve 410. The filter element 316, so therefore, it ensures the complete closure of the pressure relief valve 410 when it is in the closed state preventing the infiltration of air into the container 11 potentially damaging the contents of the container 5 11.

[0137] The integration of the filter element 328 with the filter layer 316 and the exemplary selective joint of the flexible joint 318 to the filter layer 316 provides an opportunity to construct a more compact pressure relief valve 410. A more compact and low profile 410 pressure relief valve provides opportunities

10 so that the pressure relief valve 410 goes more unnoticed when it is attached to the container 11, which can be very desirable in many packaging applications.

[0138] The drawings show pressure relief valves of particular configurations, and particular materials have been described for illustrative purposes. This invention is not limited to these or any other configuration or

15 particular material. For example, the pressure relief valve of the present invention may be circular or have other geometric shapes as required by the customer. Pressure relief valves may have metal sheet parts instead of plastic, and may optionally include an additional structure such as rails 342, 344 or ribs.

[0139] Only as an example, the present invention has been analyzed primarily in the context

of coffee packaging although it can be easily used for the packaging of other food or non-consumable products.

Claims (9)

1. A unidirectional pressure relief valve (310) for fixing on a vent in an outer surface of a closed container (11) containing a product that produces gas, having the valve of 5 pressure relief (310) • a filter layer (316) of a strip type material having a periphery (320) and first and second sides (322, 324) defining a body (326) therebetween, having the filter layer (316) a filter element (328) defining opening and barrier portions (330, 332) in the strip-like material that provide a passage of gas through 10 the opening portions (330) and the body (326) and the obstruction of particulate matter by the barrier portions (332); • adhesive (20) on the second side of the filter layer (324) to adhere the pressure relief valve (310) to the outer surface of the closed container (11); Y • a flexible joint (318) that includes a flexible cover (44) selectively attached to the first side of the filter layer 15 (322) to form a gas flow path (21) between the flexible cover (44) and the first side filter layer (322) along an unbound area of the flexible cover (44) and the filter layer (316) from the filter element (328) to the periphery of the filter layer (320) characterized because twenty • the flexible seal (318) also includes a first gas impermeable layer (26) above the filter layer (316) and around the opening portions (330) and a second gas impermeable layer (32) supported by the flexible cover (44) on the opening portions (330) of the filter layer (316), the gas impermeable layers (26, 32) having a surface attraction that maintains a gas impermeable layer against the other, 25 the flexible joint (318) having a first position in which the gas impermeable layers (26, 32) form a joint to obstruct the flow of gas through the body and an additional position in which the second gas impermeable layer of the unbound zone is spaced at least partially spaced from the first gas impermeable layer by the pressure of gas exerted through the filter element (328) to allow unidirectional gas outflow through the gas flow path ( twenty-one) 30 whereby the pressure relief valve (310) allows the flow of unidirectional pressure gas from an inside of the closed container (11) through the filter element (328) and the gas flow path (21) while preventing the particulate matter from interfering with the closure of the valve (310) once the gas pressure inside the container (11) is reduced. 35 2. The pressure relief valve (310) of claim 1 wherein the opening portions (330) defined by the filter element (328) are selected from the group consisting of calculations, slits, spikes and combinations thereof. The pressure relief valve (310) of claim 1 or 2 wherein the opening portions (330) defined by the filter element (328) are arranged in a grouping. 4. The pressure relief valve (310) of any one of claims 1 to 3 wherein the opening portions (330) defined by the filter element (328) are arranged in a cluster and the The group has a width dimension and a length dimension. 5. The pressure relief valve (310) of claim 4 wherein the width dimension of the cluster is approximately the same as the length dimension of the cluster. The pressure relief valve (310) of any of the preceding claims wherein the Filter element (328) has a mesh size between approximately 30 mesh and 200 mesh. 7. The pressure relief valve (310) of any of the preceding claims further comprising adhesive that selectively bonds the flexible joint (318) to the filter layer (316) to form the path of 55 gas flow (21). 8. The pressure relief valve (310) of any one of claims 3 to 6 wherein the unbound area of the flexible joint (318) is in a sealing support with the opening and barrier portions (330, 332 ) of the filter element (328) when it is in the first position. 9. The pressure relief valve (310) of any of the preceding claims wherein the Adhesive is selectively applied to the second side and spaced from the filter element. The pressure relief valve (310) of any of the preceding claims wherein the layer Cover (44) of the flexible joint (318) has a first side opposite the filter element (328) and the pressure relief valve further comprises at least one rail (342, 344) fixed to the first side and extending away from it. 10. The pressure relief valve (310) of any of the preceding claims wherein the layer of filter (316) and flexible joint (318) are of a biodegradable material selected from the group consisting of acid polylactic, cellulose acetate, and combinations thereof. 12. The pressure relief valve (310) of any of the preceding claims wherein the first of the gas impermeable layers (26) is of an adhesive-like material and the second of the layers Gas impermeable (32) is made of a silicone material or a dry shedding material. 13. The pressure relief valve (310) of any of the preceding claims wherein the second of the gas impermeable layers is on a membrane (36) supported by the flexible cover (44). twenty