Method and device for gas filling and sealing of a duct intended to be filled with gas and positioned in a container of a collapsible type, and container blank comprising such a duct
The invention relates to a method and a device ( 16 ) for gas filling and sealing of a duct ( 7 ) intended to be filled with gas and positioned in a container ( 1 ) of a collapsible type. The duct ( 7 ) is defined by two opposite side walls ( 2 ) which are joined along a connecting portion ( 4 ) and comprises an inlet ( 15 ) arranged in one of the side walls ( 2 ). A part of the container ( 1 ) that comprises the inlet ( 15 ) is clamped between an abutment ( 17 ) and a gas module ( 20 ) which is axially movable towards the abutment ( 17 ). Clamping occurs in such a manner that one of the two side walls ( 2 ) included in the duct ( 7 ) is allowed, in response to a gas flow supplied from the gas module ( 20 ) and entering the duct ( 7 ) through said inlet ( 15 ), to bulge to form a free passage into the duct ( 7 ) for filling the same with gas. After completion of the gas filling, the duct ( 7 ) is sealed. The invention also relates to a container blank ( 10 ) having a duct ( 7 ) which is specially developed for the method and the device ( 16 ).
1. A method of gas filling and sealing of a duct intended to be filled with gas and positioned in a container of a collapsible type, said duct being defined by two opposite side walls which are joined along a connecting portion, and comprising an inlet arranged through one of the side walls, the method comprising:
clamping a part of the container, which part comprises said inlet, between an abutment and a gas module which is axially movable towards the abutment, in such a manner that one of the two side walls included in the duct is allowed, in response to a gas flow supplied from the gas module and entering the duct through said inlet, to bulge to form a free passage into the duct for filling the same with gas, the abutment is formed with a recess in its side facing the container to allow said bulge; and
after completion of the gas filling, sealing the duct.
2. The method as claimed in claim 1 , in which said part of the container is clamped by axial displacement of a nozzle and a packing means, which is arranged outside the same and associated with the gas module, in relation to said abutment.
3. The method as claimed in claim 1 , in which the duct is sealed by applying heat and pressure to the part of the duct which abuts against the abutment.
4. The method as claimed in claim 1 , wherein the container is formed of a container blank, said container blank including the duct, characterised in that the duct includes:
a first segment which after gas filling provides a geometry desired in the container;
a second segment adjoining the first segment, said second segment having a significantly smaller cross-sectional area than the first segment; and
a third segment adjoining the second segment and comprising an inlet to the duct.
5. The method as claimed in claim 4 , in which the inlet is a hole formed in one side wall.
6. The method as claimed in claim 5 , in which the third segment is arranged in connection with a duct means of the container blank, through which duct means the container blank is adapted to be filled with its contents.