Canning and Fish Packaging Technology

Unit 3 - Unit operations in canning

3.2.4.2.Double seamers
In the joining of metal lid to the can body, curved edge of the lid is joined to edge of the body protruding out (flange) is bent and pressed with help of a machine (seamer) in two successive operations so that an air tight joint (seam) is formed. The efficiency and quality of the seam depends on the care taken during adjustment of various parts of can seamer, mechanical perfection of two interlocking hooks (body and cover) and the presence of thin lining of rubber compound. Several types of double seamers have been developed to form a seam, starting from hand operated to semi-automatic to completely automatic vacuum seamers are in use. Some seamers are slow speed whereas others seam several hundred cans per minute. Even though, there are differences in design and fabrication of various seamers, the essential parts of any seamer are as follows.

• Chuck
• Base plate
• First operation roller
• Second operation roller

Base plate holds the can in position, chuck holds the lid kept on cans in pressed condition, 1st operation roller curls the edge of the lid, presses down the flange and hooks the body flange with the cover. 2nd operation roller presses these parts close to the body and the double seam is formed.