Valve, and package

Abstract

According to one aspect of the invention, there is provided a pressure relief valve comprising a cup-shaped body (1) configured to be fixed to a flexible packaging material, the body having a bottom (11) and a peripheral wall (12). The bottom has at least one through hole (14) forming a passage through the body. The valve diaphragm is attached to the main body from the packaging side in the area around the through hole (14), and a sealing liquid is arranged between the main body and the valve diaphragm. The valve diaphragm thereby covers the at least one passage opening (14). The peripheral wall (12) has a plurality of recesses (71) on the outside thereof.

Description

Technical Field

[0001] The invention belongs to the field of pressure reducing valves used for food packaging. Background Art

[0002] Certain food products, such as freshly roasted coffee beans or ground coffee, have a tendency to outgas over a period of time. Therefore, corresponding food packaging, such as coffee bags (coffee bags), has a pressure relief valve. The pressure relief valve allows gases (such as carbon dioxide) generated inside the packaging to escape while preventing the surrounding air from entering the packaging, so that no oxygen can enter the packaging, thereby maintaining freshness.

[0003] The pressure relief valve usually has a cup-shaped body, wherein the edge of the peripheral wall of the body is welded or glued to the inside of the packaging material. The bottom of the body and the packaging both have openings. The bottom of the body rests against a disc as a valve diaphragm, which has oil (e.g. silicone oil) as a sealing liquid between the bottom and the disc. If there is an overpressure in the packaging, the gas connected through the bottom opening lifts the disc so that the gas can escape into the inside of the body and from there out of the packaging through the packaging opening. When there is no overpressure in the packaging, the disc resting against the bottom of the body ensures a leak-proof seal.

[0004] The advantage of such pressure relief valves is that they make it possible to pack fresh food directly and deliver it to the end customer without any intermediate repackaging. This has ecological advantages in addition to ensuring freshness for the customer. However, pressure relief valves increase the environmental footprint of the packaging.

[0005] Therefore, the object of the present invention is to overcome the disadvantages of the prior art pressure reducing valves.In particular, the object of the present invention is to provide a pressure reducing valve with a shape design or optimum efficiency and a minimum environmental footprint. Summary of the invention

[0006] The invention relates to a pressure relief valve, comprising a cup-shaped body arranged to be fixed to a flexible packaging material, the body having a bottom and a peripheral wall. The bottom has at least one through hole, which forms a passage through the body. The valve membrane is attached to the body from the packaging side (in the cup formed by the body) in the area around the through hole, with a sealing liquid between the body and the valve membrane. According to one aspect of the invention, the peripheral wall has a plurality of recesses on its outer side.

[0007] The side of the bottom opposite the package side is referred to herein as the "product side".

[0008] It has been found that external undercut measures, which are relatively easy to implement, are suitable for reducing the amount of material required for the pressure relief valve without any impairment of the functionality or the mechanical stability.

[0009] The channels may in particular be in the form of axially extending grooves with ribs between them.The grooves may be regularly arranged around the periphery of the body.

[0010] Cylindrical components with ribbed structures on the outside are known in the art, for example as lids for beverage bottles or other rotatable components, where the ribbed structures enhance the grip and make it easier to manually rotate the corresponding components. However, the body of the pressure relief valve is designed to be fixed to the package, rather than rotating. Nevertheless, the insight of the present invention is that a structure with grooves and ribs or other recesses on the outside of the peripheral wall of the body is advantageous because it helps to improve mechanical stability given a certain material volume - or from a different perspective, reduce the material volume required to achieve a certain mechanical stability.

[0011] In particular, it has been found that a channel structure, in particular a shape having an axially extending groove, acts to strengthen the body.

[0012] The overall shape of the body may be such that the outer surface corresponds to the surface of a substantially disc-shaped body, i.e. cylindrical or slightly conical with a relatively small axial extension, with a concave channel on the outer surface and possibly with a flange protruding outwards. Thus, the pressure relief valve can be processed, in particular attached to the interior of a package, using machines developed for processing prior art pressure relief valves without concave channels. Thus, the method of the invention does not require any additional machinery investment.

[0013] The channels may be evenly distributed - with equal spacing between adjacent channels - around the periphery of the body.

[0014] The number of grooves may be, for example, between 10 and 40, in particular between 15 and 30.

[0015] If the concave channel is an axially extending groove, the shape of its horizontal cross section (a cross section through a plane perpendicular to the axis) can be a continuously curved concave surface. In particular, the concave channel can be shallow because the central angle of the curved cross section is less than 180°, particularly less than 120° or less than 90°.

[0016] In one set of embodiments, the peripheral wall of the main body has a package-side portion of an outwardly protruding flange in addition to the structured portion of the concave channel. The structured portion may extend to the product-side end of the main body.

[0017] In one group of embodiments, the package side portion is a portion with a smooth outer surface, without any grooves or ribs. Likewise, in this group, the structured portion may optionally extend to the product side end of the main body.

[0018] As an alternative to a structured portion extending to the product-side end of the body, the outer surface of the circumferential wall of the body may even have a third portion, which is located on the product side of the structured portion and is also smooth, so that the grooves in this alternative are limited to the central (relative to the axial direction) part of the outer surface of the circumferential wall.

[0019] The bottom of the body is not affected by the recessed channel on the peripheral wall. On the product side, the bottom of the body may include at least one oil distribution groove, a liquid storage tank for containing the sealing liquid.

[0020] In one set of embodiments, in particular if the valve has a permeable membrane, the bottom of the body has at least one recess on the product side, thereby forming a recessed portion. At least one through hole (or at least one of the through holes) has its product side opening in the recessed portion. Thus, the through hole opening on the product side is offset relative to the outermost plane on the product side. This means that if a permeable membrane is present, the through hole opening is offset relative to the plane of the permeable membrane. The recessed portion can effectively constitute a system of venting grooves with spacers in between.

[0021] In some embodiments, the spacer has rounded edges. Thus, when the package is subjected to mechanical stress, there is less risk of damaging the permeable membrane.

[0022] In some embodiments, if the package is used to contain fine-grained products, such as coffee powder (ground coffee), the valve further comprises a permeable membrane attached to the product side of the bottom, covering at least one through hole to prevent the product from blocking the through hole, while being breathable. The permeable membrane may be a fabric membrane. In this article, "fabric" is used to cover all types of flexible materials interlaced by fibers or yarns or threads, including non-woven fabrics, woven or knitted textiles or other textile structures.

[0023] In some embodiments, the valve further comprises a fixing member. The fixing member is shaped to be placed on the packaging side of the valve diaphragm. It prevents the valve diaphragm from falling out of the body even in the event of a large mechanical shock to the valve. The valve may be particularly exposed to such shocks during transport and assembly if the valve is provided in the form of bulk material. In the event of a mechanical shock, the fixing member enables the valve diaphragm to remain in place, even if the adhesion of the sealing liquid may not be sufficient to do so. The fixing member may be fixed relative to the body by forming an undercut in the peripheral wall of the body so that the fixing member can be pressed into the body.

[0024] In some embodiments, the valve may be biodegradable, ie, all components may be made of biodegradable materials.

[0025] In this document, "biodegradable" may mean biodegradable according to European Standard EN 13432 (as of the end of 2021). Additionally or alternatively, it may mean biodegradable according to European Standard EN 14995 (as of the end of 2021). Therefore, "biodegradable" particularly means "biodegradable according to EN 13432 and / or according to EN 14995".

[0026] In the case of water-soluble polymers mentioned in this context, such water-soluble polymers are selectively degradable in sewage treatment plants in accordance with DIN EN ISO 9888 (as of the end of 2021) (aerobic biodegradability); determined according to the so-called Zahn-Whillens test.

[0027] In particular, at least one component of the valve, such as the body, may be made of a polymer composition comprising a water-soluble polymer. In some embodiments, the polymer composition further comprises a salt, in particular a hygroscopic salt.

[0028] In addition to the water-soluble polymer and the salt, the composition may also contain a plasticizer. The plasticizer may be selected from the group consisting of polyols (oligohydroxy compounds and polyhydroxy compounds) and low molecular weight amides.

[0029] In some embodiments, the body and, if present, the permeable membrane and the fixing member are each made of a polymer composition comprising polyvinyl alcohol (PVOH) as a water-soluble polymer, a salt, and glycerol as a plasticizer.

[0030] In some embodiments, the valve membrane is made of a water-insoluble but biodegradable polymer composition, such as polyhydroxybutyrate (PHB).

[0031] In addition to being related to a pressure reducing valve, the present invention also relates to a packaging, in particular a coffee bag for coffee beans or ground coffee. The packaging comprises a flexible, pliable packaging material and a pressure reducing valve as described herein. The body of the pressure reducing valve is attached to the packaging material. In particular, the annular end face of the pressure reducing valve can be attached to the packaging material, wherein the valve diaphragm (and, if present, the fixing member) is arranged in a cavity between the bottom of the body and the packaging material. The packaging material is usually airtight, but has an opening or other permeable structure at a position surrounded by the peripheral wall of the body. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The embodiments of the present invention are described below in conjunction with the accompanying drawings. In the accompanying drawings, the same numbers represent the same or corresponding elements. The accompanying drawings show:

[0033] Figure 1 Exploded view of the pressure reducing valve assembly;

[0034] Figure 2The subject's view;

[0035] Figure 3 a cutaway view of the assembled pressure reducing valve;

[0036] Figure 4 different views of the subject;

[0037] Figure 5 Another view of the subject;

[0038] Figure 6 Another view of the assembled pressure reducing valve in section;

[0039] Figure 7 Alternative embodiments of the subject;

[0040] Figure 8 Yet another alternative embodiment of the subject;

[0041] Fig. 9 a side view schematically showing yet another embodiment of the body; and

[0042] Fig.10 The pressure relief valve in the package is shown schematically. DETAILED DESCRIPTION

[0043] Figure 1 , 3 The pressure reducing valve shown in FIG. 6 includes a main body 1, which is also shown in FIG. Figure 2 , 4 and 5. The main body 1 has the overall shape of a flat cup, with a bottom 11 and a peripheral wall 12. The bottom 11 has a sealing surface and a surface on the product side opposite to the sealing surface.

[0044] The peripheral wall 12 surrounds the sealing surface of the base 11. It has a substantially cylindrical or slightly conical outer surface with axially extending grooves 71 arranged at regular intervals and between these grooves there are ribs 72. The axially extending ribs 72 enhance mechanical stability even if the peripheral wall 12 is relatively thin (i.e. made of minimal plastic material).

[0045] The peripheral wall 12 in this embodiment also has a flange 13, i.e. a shoulder protruding outward, at its end facing away from the bottom 11, so that the annular end face 16 with the energy guiding ribs 18 on the packaging side is wider. The bottom has at least one through hole 14 (three through holes 14 in the described embodiment), which is covered by the valve membrane 2 which is attached to the sealing surface of the bottom 11. There is a thin layer of sealing liquid, especially oil, such as silicone oil, between the bottom 11 and the valve membrane 2.

[0046] In this context, “circumferentially” as well as “radially” or “outwardly” or “inwardly” are referenced to the axis 10 of the body.

[0047] The body 1 comprises, inside the peripheral wall 12 and in the plane defined by the valve membrane 2, an extension accommodating groove 41 which accommodates any extension of the valve membrane so that the valve membrane does not bulge when it expands, for example if the valve membrane absorbs some moisture.

[0048] In some embodiments, the pressure reducing valve has a permeable membrane 3 in addition to the body 1 and the valve membrane 2. The permeable membrane 3 can be a fabric, such as a non-woven fabric. The permeable membrane is attached to the surface of the product side of the bottom and covers at least the through hole 14.

[0049] On one side of the sealing surface, the main body has a plurality of oil distribution grooves. More specifically, the main body has an inner oil distribution groove 21 surrounding the opening, and further has a circle of three first outer oil distribution grooves 22 and a circle of three second outer oil distribution grooves 23, wherein the first outer oil distribution grooves 23 are arranged around the second outer oil distribution grooves 22.

[0050] The outer oil grooves have the function of serving as sealing liquid reservoirs. For this purpose, they are located in a radial position so as to be covered by the valve diaphragm (see e.g. Figure 3 or Figure 6 ).

[0051] In some embodiments, the pressure relief valve has a fixing member 4 in addition to the body 1 and the valve membrane 2 and, if applicable, the permeable membrane 2. The fixing member 4 is optional and can be used as a spacer between the flexible packaging material and the valve membrane 2 to ensure that the valve membrane 2 will not shift even in the event of severe mechanical shock. In the embodiment shown, the fixing member 4 is a star-shaped member with three spokes.

[0052] On the product side, the body 1 is constructed to include a system of venting grooves 31 and spacers 33. This system allows the through holes 14 to be located at the bottom of the venting grooves, ie where the surface on the product side is recessed.

[0053] exist Figure 1-6 In the embodiment of the present invention, the overall shape of the body with the flange 13 and the widened end face 16 (which is bonded to the packaging material) may facilitate the process of bonding the valve to the packaging material and the stability of the bonding. That is, the shoulder defined by the flange as an outwardly protruding shoulder forms a coupling surface 17, and the tool for bonding the valve to the packaging material can directly act on this coupling surface 17. Therefore, the energy (usually ultrasonic energy) coupled into the body 1 by the tool for the bonding process does not need to be coupled through the entire height (axial extension) of the body, but only through the thickness of the flange 13. This makes the bonding process more efficient compared to the case where the tool is pressed against the end face of the body on the product side.

[0054] The tool can be, for example, a tubular sonotrode, the tube diameter of which corresponds approximately to the diameter of the flange 13 .

[0055] However, the flange 13 and the widened end face 16 are only optional. In alternative embodiments, the body 1 does not have such a structure. In these alternative embodiments, the body 1 can also be welded to the packaging material by applying a sonotrode to the end face of the body on the product side. Also in these embodiments, the sonotrode used can optionally be tubular, with a tube diameter greater than the outer diameter of the area with the venting groove system and the spacer. However, alternatively, the sonotrode can have a flat outer coupling face.

[0056] Figure 7 A corresponding embodiment without flanges is shown. Figure 1-6 As in the embodiment of the present invention, the axially extending groove extends from the product side end of the body. On the packaging side, in addition to the portion with the axially extending groove, the outer surface of the peripheral wall also has a second smooth portion 74, but without the same flange as in the previous embodiment. Energy guiding ribs ( Figure 7 The outer surface of the packaging (not visible in the figure) can be arranged on the side end surface of the packaging formed by the peripheral wall.

[0057] Figure 8 Another variant is shown, in which the concave channel is not an axially extending rib, but has an oval shape. Thus, the outer surface of the peripheral wall has not only a first portion with concave channels and a second portion 74 with a smooth portion on the packaging side, but also a third portion 75 on the product side (also a smooth portion).

[0058] Other shapes of the recesses are possible. Fig. 9 It is shown very schematically that there is the possibility that the outer surface of the peripheral wall can have an axially extending groove 71 which does not extend to the product-side surface.

[0059] The pressure relief valve for this purpose is placed in an airtight flexible package, wherein the annular end surface 11 of the peripheral wall is bonded to the inner surface of the package, for example by welding. Fig.10 A package with a valve is schematically shown, with a body 1 welded to a packaging material 60. The packaging material has at least one gas channel (e.g. at least one through hole or permeable portion) at a location surrounded by the annular end surface. If there is an overpressure in the package, the gas will cause the valve membrane 2 to rise from the bottom 12, thereby forming a gas channel. Excess gas can then escape through the through hole 14, between the valve membrane and the bottom and through the gas channel of the package. When there is no overpressure in the package, the valve membrane closes the package by resting against the bottom, and the sealing liquid adheres to the bottom and the valve membrane by capillary forces to form a seal.

Claims

1. A pressure reducing valve, comprising: A cup-shaped body (1) configured to be fixed to a flexible packaging material, comprising a bottom (11) and a peripheral wall (12), wherein the bottom (11) has at least one through hole (14) forming a passage through the body; a valve membrane (2) which abuts against the body from the packaging side in an area around the at least one through hole (14); and a sealing liquid between the body (1) and the valve membrane (2), characterized in that a plurality of grooves (71, 81) are provided on the outer surface of the peripheral wall.

2. A valve according to claim 1, wherein the recesses (71, 81) are evenly distributed around the outside of the peripheral wall (12).

3. A valve according to claim 1 or 2, wherein the channels are axially extending grooves (71) extending from the product-side end of the body and having ribs (72) between the grooves (71).

4. A valve according to any one of the preceding claims, wherein the outer surface of the peripheral wall, apart from the recesses (71, 81), is cylindrical or slightly conical.

5. Valve according to any of the preceding claims, wherein the peripheral wall comprises energy-directing peripheral ribs (18) at the package-side end face.

6. Valve according to any of the preceding claims, wherein the peripheral wall comprises an outwardly protruding flange (13) at the package-side end.

7. A valve according to any one of the preceding claims, wherein the outer surface of the peripheral wall has a structured portion with grooves (71, 81) and also has a smooth portion (74, 75) axially spaced apart from the structured portion.

8. A valve according to any one of the preceding claims, wherein at least one component of the valve is made from a polymer composition comprising a water-soluble polymer.

9. A valve according to any preceding claim which is biodegradable.

10. Valve according to any one of the preceding claims, further comprising a permeable membrane (3) in the form of a fabric fixed to the body (1) for covering at least one through hole (14) on the product side opposite to the packaging side.

11. Valve according to any of the preceding claims, wherein the body has a system of ventilation grooves with spacers between them, at least one of the through holes (14) or the opening of the through hole (14) being located in a ventilation groove.

12. The valve according to any one of the preceding claims, further comprising a fixing member (4) fixed relative to the peripheral wall, such that the valve membrane (2) is sandwiched between the bottom (11) and the fixing member (4).

13. A package for packaging a food product, the package comprising a flexible, pliable packaging material (60) and a pressure relief valve according to any one of the preceding claims, wherein the body (1) is attached to the packaging material (60).

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