In-line coating of steel tubing

摘要

A method and apparatus for applying a coating to a continuous length of tubing (16). A coating chamber (10) having entry (12) and exit (14) ports substantially encloses a portion of the tubing while permitting the tubing to pass continuously therethrough. Airflow into the coating chamber through the exit port strips excess coating material from the tubing surface. Air is withdrawn from the coating chamber by vacuum pumps (28) through one or more separation chambers (24,26) which separate entrained particles or droplets of coating material from the air. The coating chamber is preferably disposed at a distance from the separation chamber(s). The vacuum line (30) connecting the coating chamber with the separation chamber(s) is preferably flexible or breakable. The separation chambers are preferably capable of being operated in series or in parallel. Adjustable masks (52,54) are preferably provided at the entry and exit ports of the coating chamber. A seal (5) is preferably provided at the entry port. $$