BACKGROUND OF THE INVENTION

1. Field of the invention

The present invention relates to a novel and improved valve assembly for bulk containers with liner.

2. Description of related prior art

Products made of thermoplastic materials can be manufactured by a number of different manufacturing procedures. The most commonly used methods are however, injection moulding, vacuum forming, blow moulding and press moulding.

Valves of butterfly and of ball type have been known for some time and they can be manufactured from thermoplastic material. Here injection moulding and press moulding are the most suited manufacturing methods in order to achieve the desired precision. Butterfly valves and ball valves made of thermoplastic materials are mostly used in low-pressure systems. Butterfly valves are often used in ventilation appliances where absolute closing isn't necessary. It is also possible to use the valves for fluid media. It will of course be important to have gaskets both in the valve seat as well as at the end of the valve housing. These gaskets are typically made from an elastomeric material, most commonly a thermoplastic material with a plasticizer additive. In many cases the valve is designed in such a way that material recovery is virtually impossible.

One area where such valves are frequently used is bulk goods where foldable pallet containers are provided with a bag shaped liner having a valve at the base intended for releasing the goods. This type of packaging is often used in the food industry and will therefore need attention regarding choice of material as well as hygiene. Steam sterilization of the valve area is frequently used before a container is connected to further processing and emptied. This will put some demands on the material used for making the components of the valve.

It is furthermore desirable to be able to recover packaging material after use which has proven difficult with previous solutions.

SUMMARY OF THE INVENTION

It has through the present invention been made possible to make the manufacturing process more effective and at the same time allowing considerable improvements in mechanical characteristics.

Accordingly, the present invention relates to a valve assembly intended for use together with a pallet container and a liner. The valve assembly comprises a valve, a valve seal and an outer lip seal, wherein the valve assembly comprises a support member. The support member comprises a lower guide member and an upper guide member. The valve is advantageously a butterfly valve.

The valve is preferably provided with lower and upper axle ends. The lower guide member and upper guide member are provided with guiding holes intended to receive and guide the lower and upper axle ends of the valve.

The valve seal and outer lip seal preferably constitute parts of a mainly tube shaped body. The tube shaped body is further provided with a flange and holes with seals intended to receive lower and upper axle ends of the valve. The tube shaped body is preferably made of a flexible thermoplastic material compatible with that of the liner. The flexibility is mainly obtained by making desired portions of the tube shaped body thin walled.

A suitable material for the tube shaped body is a thermoplastic material selected from the group consisting of low-density polyethylene, linear low-density polyethylene, polypropylene and polyamide.

The tube shaped body acts as a gasket and provides a seal towards the part selected from the group consisting of; valve, an outer media via an outer lip seal, a lower axle end and an upper axle end as well as a combination thereof.

The support member suitably further comprises means for attaching an outer media selected from the group consisting of; a thread, a flange and a combination thereof.

The support member provides mechanical stability and support to the tube shaped body wherein the support member is manufactured of a rigid material selected from the group consisting of; high-density polyethylene, polypropylene, polyamide, polycarbonate, acrylonitrile butadiene styrene co-polymer, polyoxymethylene, polyalkylene terephthalate, polybutylene terephthalate and polyphenylene oxide. This rigid material may further include filler selected from the group consisting of; lime, mica, glass fibre, carbon fibre, aramide fibre and combinations thereof.

The valve itself is suitably of the so-called butterfly type which advantageously is made of a material selected from the group consisting of; high-density polyethylene, polypropylene, polyamide, polycarbonate, acrylonitrile butadiene styrene co-polymer, polyoxymethylene, polyalkylene terephthalate, polybutylene terephthalate and polyphenylene oxide. The valve is advantageously further provided with a circumambient gasket made from a thermoplastic elastomer. This gasket is suitably moulded onto the valve in order to increase its ability to withstand the shear-force during opening and closing of the valve.

The valve outlet according to the present invention is suitably assembled by pressing the valve into the tube shaped body so that the lower and upper axle ends is positioned in the holes with seals. The axle ends may be a part of the moulded valve, but may also be one or more separate parts, which are inserted into the valve once in the proper position in the tube shaped body. The lower guide member and upper guide member are then attached around the tube shaped body so that the guiding holes receive and guide the lower and upper axle ends of the valve.

According to one embodiment of the invention the lower guide member and upper guide member are snap fitted over the tube shaped body. This will allow a quick disassembly without any need for special tools for material recovery purpose.

According to one embodiment of the invention he tube shaped body is provided with an annular internal grove matching the closed position of the valve. This will reduce the risk of leakage, reduce the risk of unintentional opening of the valve and also provide a tactile confirmation when closing and opening a valve. It is, according to an alternative embodiment of the invention possible to achieve a similar effect by providing the support member with an annular internal grove matching the closed position of the valve. DESCRIPTION OF AN EMBODIMENT EXAMPLE

The invention is further described together with enclosed drawing showing a selected embodiment of the invention, wherein,

-figure l a show, in perspective view as seen from below, an embodiment of a valve assembly 3 according to the invention.

-figure lb show, in perspective view as seen from above, an embodiment of a valve assembly 3 according to the invention.

-figure l c show, in perspective view and in exploded view, an embodiment of a valve assembly 3 according to the invention.

The valve assembly 2 as shown in figure l a - l c is intended for use together with a pallet container (not shown) and a liner (not shown). A liner is, in the light of the present invention understood as a flexible, closed bag of two or more layers of polyethylene film. The liner bag is usually provided with a closable opening at the top for filling and a closable opening at the bottom for emptying.

As shown in figure 1 a - c, the valve assembly 2 comprise a valve 3, a valve seal 4 and an outer lip seal 5. The valve assembly 2 further comprise a support member 6. The support member 6 comprises a lower guide member 61 and an upper guide member 62. The valve 3 is provided with lower and upper axle ends 31 and 32 respectively. The lower guide member 61 and upper guide member 62 are provided with guiding holes 63 and 64 respectively, intended to receive and guide the lower and upper axle ends 3 1 and 32 respectively of the valve 3. The valve seal 3 and outer lip seal 5 constitute parts of a mainly tube shaped body 30. The tube shaped body is further provided with a flange 33 and holes with seals 34 intended to receive lower and upper axle ends 31 and 32 respectively, of the valve 3. The tube shaped body 30 is made of the same thermoplastic material type as that of the liner. The flange 33 can then with ease be welded onto the liner itself. The latter is great advantage, which will increase productivity as well as minimise the risk for leakage. The flexibility is mainly obtained by making desired portions of the tube shaped body 30 thin walled. The liner and the tube shaped body 30 are accordingly made from linear low-density polyethylene. The tube shaped body 30 acts as a gasket and provides a seal towards the valve 3, an outer media via an outer lip seal 5, the lower axle end 3 1 and the upper axle end 32. The tube shaped body 30 is further provided with an annular internal grove matching the closed position of the valve 3. The annular internal groove is not visible in the figures, but is coinciding with the position of the valve seal 4 seen in figure l c. This will reduce the risk of leakage, reduce the risk of unintentional opening of the valve 3 and also provide a tactile confirmation when closing and opening a valve 3. It is according to one alternative embodiment of the invention possible to provide the annular internal groove (not shown in the figures) on the inside of support member 6, matching the closed position of the valve 3.

The support member can 6 further comprises means for attaching an outer media a standard thread (not shown). It is further suitable to also provide a cap 6 to protect the outer face of the valve 3 and the outer portions of the tube shaped body 30 from dirt during transport and storage.

The support member 6 provides mechanical stability and support to the tube shaped body 30. The support member 6 is manufactured of polycarbonate, which is a rigid material.

The valve outlet is assembled by pressing the valve 3 into the tube shaped body 30 so that the lower and upper axle ends 3 1 and 32 respectively is positioned in the holes with seals 34 whereupon the lower guide member 61 and upper guide member 62 are attached around the tube shaped body 30 so that the guiding holes 63 and 64 respectively receive and guide the lower and upper axle ends 31 and 32 respectively of the valve 3.

The lower guide member 61 and upper guide member 62 are snap-fitted over the tube shaped body 30. This will allow the assembly as well as a disassembly to be performed with ease. In cases where the liner, including the valve assembly is used for foodstuff, the liner is rarely reused due to hygiene reason. A valve assembly 2 according to the present invention is very easy to disassemble without the need for any special tools. The upper and lower guide member 61 and 62, being made from a material different from the liner bag and tube shaped body 30, can be reused, possibly after cleaning, as it will not be in direct contact with the contents of the liner bag. The material of the liner bag and the tube shaped body 30 attached thereto can be recovered. The invention is not limited by the embodiments shown since these can be varied in different ways within the scope of the invention.