Manufacture of roll formed tubes

A welded tube roll forming apparatus (200) comprising a roll forming section (202) configured to form a metal strip (102) into a tube (100), followed by a welding section (201) comprising a high frequency induction weld coil (203) and a pair of weld rollers (204) and being configured to weld together the longitudinal edges (101) of a metal strip (102), which is being roll formed into a tube (100), while the tube is forwarded through the apparatus in a travel direction (T),

• wherein the apparatus further comprises vacuum extraction section (205) configured to extract solid particles produced inside the tube (100) during the high frequency induction welding of the tube edges, said vacuum extraction section (205) being located between the weld coil (203) and the roll forming section (202) where the edges (101) of the roll formed tube have not yet been welded together,
• wherein the vacuum extraction section (205) comprises the seam guide assembly (1), said seam guide assembly (1) comprising a front seam guide tip component (2), which is attached to a holder (3) in such a way that an elongated tip (4) protrudes from a first side (5) of the holder (3), said tip (4) being configured to be inserted between the tube edges (101) to be welded,
• wherein a through channel (6) is provided in the holder (3), said channel having an inlet opening (7) located on said first side (5) of the holder, adjacent the front seam guide tip component (2) in a longitudinal direction of the holder, and an outlet opening (8) located on a second side (9) of the holder, said outlet opening being configured to be connected to a vacuum source, and
• wherein the through channel (6) is configured for removal of emission of solid particles resulting inside the tube (100) due to welding by means of applying a vacuum at the outlet opening (8), and the inlet opening (7) of the channel (6) has an elongated shape directed in the longitudinal direction of the holder (3).