| abstract |
A system of precipitating dust includes providing a screen arrangement either in the form of a ceiling with walls or in the form of a canopy with the screen being penetrable by air. Inside the screen and particularly adjacent edges of the screen or the canopy there are provided negative ion emitters positioned in rows so as to generate a curtain of ions precipitating the dust from the air onto the ground for collection. Within the screen can be defined either a clean zone or the screen can be used to confine a dust producing process so as to precipitate the dust immediately adjacent the process to prevent it spreading to other areas. Emitters are provided in the form of a carbon fiber yarn which projects outwardly through openings in a channel member with the yarn being doubled back upon itself in some cases to provide a highly directional emission. |