A method for the manufacture of composite cans and a composite can made by the method

Abstract

A method for manufacturing and filling a composite can (201), the method comprising: —forming a tubular body (203) by bending a body blank (16) and bringing two opposing edges of the body blank (16) together in an end-to-end join; —sealing the join by welding a sealing strip (214) over the join, thereby forming an intermediate can (403; 503); —sealing a top opening (211) by attaching a top sealing member (227) across the top opening (211); —applying a top rim (223) to the intermediate can (403; 503) by welding an inserted part of the top rim (223) to the inner surface of the tubular body (203); —turning the intermediate can (403; 503) upside-down and placing the intermediate can (403; 503) on a conveyor (2a) with the top rim (223) resting on the conveyor (2a); filling the intermediate can (403; 503) through the bottom opening (213); —sealing the bottom opening (213) of the tubular body (203) by attaching a bottom sealing member (215) across the bottom opening (213); —turning the intermediate can (403; 503) to bring the top rim (223) in an upward-facing position; —attaching a reclosable lid (221) at the top end of the tubular body (203). The intermediate can is kept in a protective gas atmosphere from said filling of said intermediate can until said bottom opening (213) of said tubular body (203) has been sealed. An assembly line (1) for manufacturing and filling of composite cans (201) is also disclosed.

1 . A method for manufacturing a composite can and filling of dry or moist goods in said composite can, said method comprising:
 picking a body blank from a pile of body blanks and transferring said body blank to a body forming station;   forming a tubular body by bending said body blank and bringing two opposing edges of said body blank together in an end-to-end join, said join extending in a height direction of said tubular body;   sealing said join by welding a sealing strip over said join on an inner surface of said tubular body, thereby forming an intermediate can;   transferring said intermediate can to a top sealing station;   sealing a top opening at a top end of said tubular body by welding a peripheral flange of a top sealing member to said inner surface of said tubular body at a distance from a top end edge of said tubular body;   transferring said intermediate can to a conveyor and placing said intermediate can on said conveyor a bottom opening at a bottom end of said tubular body facing upward in a vertical direction;   transferring said intermediate can to a filling unit;   filling said intermediate can with said dry or moist goods through said bottom opening of said tubular body;   subjecting said intermediate can to a protective gas atmosphere either during said filling of said intermediate can or by introducing said filled intermediate can into a vacuum chamber to draw off air;   transferring said filled intermediate can to a sealing unit, said filled intermediate can being transported to said sealing unit in a closed conveying system while maintaining said protective gas atmosphere;   sealing said bottom opening of said tubular body by welding a peripheral flange of a bottom sealing member to said inner surface of said tubular body at a distance from a bottom end edge of said tubular body, sealing of said bottom opening being carried out while maintaining said protective gas atmosphere;   turning said filled and bottom sealed intermediate can to bring said top end of said tubular body in an upward-facing position in said vertical direction and transferring said intermediate can to a lid attachment unit; and   attaching a reclosable lid at said top end of said tubular body with an inner surface of said reclosable lid in direct contact with an upper surface of said top rim.   
     
     
         2 . The method according to  claim 1 , wherein the following steps are performed after sealing of said top opening:
 transferring said intermediate can to a top rim application station;   applying a top rim to said intermediate can by inserting at least a lower part of said top rim into said top opening, above said top sealing member;   welding said inserted part of said top rim to said inner surface of said tubular body;   transferring said intermediate can to said conveyor and placing said intermediate can on said conveyor with said top rim resting on said conveyor and said bottom opening at said bottom end of said tubular body-R facing upward in a vertical direction;   
     
     
         3 . The method according to  claim 1 , wherein tightly fitted lead-in and outlet tunnels are arranged at an inlet and at an outlet of said sealing unit. 
     
     
         4 . The method according to  claim 1 , wherein said method comprises supplying a protective gas such as nitrogen, carbon dioxide or a mixture of nitrogen and carbon dioxide to said dry or moist goods during filling of said intermediate can and/or after filling of said intermediate can. 
     
     
         5 . The method according to  claim 1 , wherein said sealing unit is arranged in an external housing and is arranged to operate in a protective gas atmosphere in said external housing. 
     
     
         6 . The method according to  claim 5 , wherein an outlet port for said intermediate can is arranged in said external housing of said sealing unit-, wherein a size of said outlet port is adapted to a size of said intermediate can being processed. 
     
     
         7 . The method according to  claim 6 , wherein said outlet port comprises a short tunnel arranged at an end of an outlet conveyor member, wherein a stationary sliding plate constitutes a floor in said tunnel. 
     
     
         8 . The method according to  claim 6 , wherein an inlet port for said intermediate can is arranged in said external housing of said sealing unit- and a closable hatch is arranged at said inlet port. 
     
     
         9 . The method according to any one of the preceding  claim 1 , wherein said method further comprises:
 applying a bottom rim to said bottom end of said bottom sealed intermediate can;   placing said bottom sealed intermediate can on a conveyor with said bottom rim resting on said conveyor-Rd) during said transfer of said intermediate can to said lid attachment unit.   
     
     
         10 . The method according to  claim 1 , wherein a scoop is applied between said top sealing member and said reclosable lid before attaching said reclosable lid at said top end of said tubular body, said scoop being applied directly on said top sealing member or being placed in a scoop holder which is arranged above said top sealing member. 
     
     
         11 . The method according to  claim 1 , wherein two or more intermediate cans are processed simultaneously during one or more of:
 sealing said top opening;   applying said top rim;   welding said top rim;   filling said intermediate can;   sealing said bottom opening; and   attaching said reclosable lid.   
     
     
         12 . An assembly line for manufacturing of composite cans and filling of dry or moist goods in said composite cans according to the method of  claim 1 , said assembly line comprising a plurality of machine units connected by conveyors, wherein said machine units comprise:
 a body forming unit;   a filling unit;   a sealing unit; and   a lid attachment unit.   
     
     
         13 . The assembly line according to  claim 12 , wherein a gas box is arranged between said filling unit and said sealing unit. 
     
     
         14 . The assembly line according to  claim 12 , wherein said sealing unit comprises a can sealing station and a rim application station. 
     
     
         15 . The assembly line according to  claim 12 , wherein said sealing unit is arranged in an external housing and is arranged to operate in a protective gas atmosphere in said external housing.