Scraping bar for use in pocket of e.g. paper machine, has distribution duct system standing in connection with air duct, where air layer is formed between bar and boundary layer air from air flow of boundary layer air

摘要

The bar (1) has air duct for supplying an air flow of boundary layer air (8) into a pocket (50), where the bar is made of fiber-reinforced plastic composite material. A distribution duct system stands in connection with the air duct, for accepting an influence of temperature- and/or humidity distribution of pocket air in a transverse direction. The air flow of the boundary layer air flowing over a scraping blade (10) is controllable, such that an air layer is formed between the bar and the boundary layer air from the air flow of the boundary layer air, for cooling and/or isolating the bar. Independent claims are also included for the following: (1) a method for influencing on a fibrous web in a fibrous web-machine (2) a method for protecting a scraping bar from an environmental thermal stress.