The invention relates to a gas bottle, in particular a portable one, which is preferably going to be used to feed gas to an external user device, for example a barbecue, cookers, lamps and similar devices.

Bottles of the above-mentioned type are known, which basically comprise:

• a sealed container, which is filled with a gas under pressure, for example butane gas or a mixture of butane and propane gas, and is provided, on an upper wall thereof, with a perforable portion to allow gas to be fed to the external user device; and
• an outflow limiting valve, or safety valve, which is positioned inside the container so as to limit or prevent the outflow of gas in case the perforable portion gets perforated and the gas bottle is not connected to the external user device.

In particular, the valve is usually fixed on the inside of the container of the bottle by means of a support structure fitted between the upper wall of the container and its side wall, on which it abuts in the area of a suitable annular inner shoulder.

This solution is quite complicated and, especially, expensive in terms of total selling cost of this type of gas bottles.

Therefore, the need is felt in the industry for alternative valve fixing systems, which should be more simple and less expensive compared to known ones.

WO 2015/092447 shows an outflow limiting valve for a gas bottle, which is fixed, by means of an adhesive substance or by means of a support frame, around the perforable portion of the upper wall of the container of the gas valve.

In particular, the valve is entirely made of an elastically flexible material and comprises a main body, which is fixed to the upper wall of the container, and a movable part, which is perforated, in use, together with the perforable portion when the gas bottle is connected to the external user device.

In case the external user device is detached from the gas bottle, the movable part, pushed by the pressure of the gas, should bend upwards, thus closing the hole made in the perforable portion of the gas bottle. However, it has been proven that the pressure of the gas inside the container of the bottle is not usually sufficient to cause the movable part to obstruct the hole of the perforable portion.

Therefore, the object of the invention is to provide a gas bottle, which fulfils the aforesaid need and, at the same time, allows to overcome the drawbacks of the known solutions mentioned above, in particular ensuring, in use, an effective and reliable closing of the gas bottle after the detachment of the external user device.

The aforesaid object is reached by the present invention, as it relates to a gas bottle according to claim 1.

The invention will be best understood upon perusal of the following description of two embodiments, which is provided by mere way of non-limiting example and with reference to the accompanying drawings, wherein:

• figure 1 shows a perspective view of a gas bottle according to the invention;
• figure 2 is a cross section, on a larger scale, according to line II-II of figure 1;
• figure 3 shows, in a perspective view and on a larger scale, an outflow limiting valve of the gas bottle of figures 1 and 2; and
• figures 4 to 6 are similar to figure 3 and show three different possible variants of the valve of figure 3.

With reference to figures 1 and 2, number 1 indicates, as a whole, a gas bottle manufactured according to the present invention.

The bottle 1 comprises a sealed container 2, which is filled with a gas under pressure, preferably butane gas or a mixture of butane and propane gas, and is provided, on an upper wall 3 thereof, with a perforable portion 4 to allow gas to be fed to an external user device (known per se and not shown), for example a barbecue, cookers or lamps.

The bottle 1 further comprises an outflow limiting valve, or safety valve 5, which is positioned inside the container 2 so as to limit or prevent the outflow of gas in case the perforable portion is perforated and the gas bottle 1 is not connected to the external user device.

In particular, with reference to figure 1, the container 2 preferably has an approximately cylindrical shape with an axis A. More precisely, the container 2 is delimited, besides by the upper wall 3 having a circular profile, by a lower wall 6, which is substantially shaped like a disc, and by a side wall 7, which is approximately cylindrical.

The upper wall 3 is slightly convex toward the outside and has a central circular impression, which is convex toward the inside of the container 2 and defines the perforable portion 4.

The valve 5 is manufactured as one single piece and is fixed, exclusively by means of a layer of adhesive substance 9, to the upper wall 3 of the container 2 around the perforable portion 4.

It is specified that, in the present description and in the claims, the term "around" is used to indicate both the peripheral edge of the perforable portion 4 and the annular area immediately surrounding the perforable portion 4.

In the embodiment shown in figures 1 and 2, the layer of adhesive substance 9 is applied around the perforable portion 4 and is interposed between the valve 5 and the upper wall 3.

The adhesive substance preferably is an acrylic adhesive, which, following different experiments carried out by the Applicant, has been proved to be suitable to crate a particularly long-lasting connection in the dry environment defined by butane gas or by the mixture of propane and butane gas.

With reference to figures 1, 2 and 3, the valve 5 preferably is similar to the one commonly known as "single duckbill valve", is made of an elastically deformable material and integrally comprises:

• a ring portion 10, which is fixed to the upper wall 3 by means of the layer of adhesive substance 9; and
• an opening/closing portion 11, which is shaped like a duck's bill and projects toward the inside of the container 2 starting from the ring portion 10.

The ring portion 10 defines an external annular shoulder 12 with the closing/opening portion 11 and is connected, at its opposite axial end, to the upper wall 3 by means of the layer of adhesive substance 9.

The closing/opening portion 11 is delimited by two flat walls 13, which are inclined and converge toward one another staring from the ring portion 10, so as to form a flat, free end wall 14, which is provided with a linear slot 15.

The closing/opening portion 11 is further delimited, on opposite sides, by respective curved walls 16 with an approximately trapezoidal profile, which connect the corresponding side edges of the flat walls 13 to one another.

In particular, the end wall 14, the flat walls 13 and the curved walls 16 delimit the closing/opening portion 11 of the valve 5 toward the inside of the container 2.

Advantageously, the slot 15 is laterally delimited by material flaps 15a, which can be spread apart in an opening configuration due to the connection to the external user device, and can be closed back against one another along the wall 14 in the absence of a connection to the external user device and due to the pressure exerted upon the flaps 15a themselves by the gas contained in the container 2. Figures 4, 5 and 6 show three possible variants of the valve 5, indicated with numbers 5', 5", 5''', respectively, which will be described hereinafter only in their differences from the valve 5, thus indicating with the same reference numbers those parts that are equal or equivalent to the ones already described.

In particular, the valve 5' of figure 4 basically differs from the aforesaid valve 5 because it is a double duckbill valve; in this case, in practice, the valve 5' comprises a closing/opening portion 11', which is formed by two duck's bills, which intersect one another so as to form a cross-shaped, free end wall 14', which is provided with a cross-shaped slot 15'.

The valve 5" of figure 5 basically differs from the aforesaid valve 5 because it does not comprise a slot along the end wall 14; in this case, therefore, the opening/closing portion 11 is closed and it can be perforated, in use, together with the perforable portion 4 of the upper wall 3 of the container 2.

Similarly, the valve 5''' of figure 6 is of the same type as the valve 5' of figure 5 and basically differs from it because it does not comprise a slot along the end wall 14'; in this case, therefore, the opening/closing portion 11 is closed, as well, and it can be perforated, in use, together with the perforable portion 4 of the upper wall 3 of the container 2.

In use, the bottle 1 must be perforated in the area of the perforable portion 4 before being connected to the external user device.

In case the bottle 1 is fitted with one of the valves 5" or 5''', the perforating operation must be extended to the valves 5", 5''' so as to allow gas to be fed to the external user device.

The presence of the valves 5, 5', 5", 5''' prevents or limits the outflow of gas from the relative bottle 1 in case the latter was perforated but is not connected to the external user device.

In this case, indeed, the flaps 15a close back against one another along the lying plane of the end wall 14 due to the pressure of the gas contained in the bottle 1.

The features of the bottle 1 according to the present invention lead to evident advantages that can be obtained using it. In particular, in both solutions, the fixing of the valve 5, 5', 5", 5''' to the upper wall 3 of the container 2 is carried out in a simple and economic manner.

The duckbill valves 5, 5', 5", 5''' used, following the perforating action that allows the bottle 1 to be used, are kept in the closed condition in a "natural" manner and by means of limited movements of the flaps 15a along the lying plane of the end wall 14, which are generated due to the pressure of the gas inside the container 2. Therefore, in case a still full bottle 1 is detached from the external user device, the valve 5, 5', 5", 5''' is capable of controlling, in an effective and reliable manner, the outflow of the remaining gas from the container 2.

It is clear that the gas bottle 1 described and shown herein can be subjected to changes and variations, without for this reason going beyond the scope of protection set forth in the appended claims.