Apparatus for the continuous surface treatment of sheet material

An apparatus for the continuous surface treatment of a length of sheet material, comprising

• a treating chamber adapted to receive therein helium gas or a gas mixture predominantly comprising helium gas and including entrance and exit ports for passage of a length of sheet material therethrough,
• means in the chamber for creating a plasma region in the helium gas or gas mixture,
• vent means for evacuating air from within said chamber,
• feed means for feeding helium gas or a gas mixture predominantly comprising helium gas into said chamber,
• seal means for sealing the entrance and exit ports in a less than gas tight manner to allow leakage of the helium gas or gas mixture, and
• means for continuously moving the length of sheet material into and out of said chamber through the entrance and exit ports,
• whereby the sheet is passed through the plasma region where the sheet on its surface is continuously subjected to plasma discharge treatment.