Apparatus for removal of electric charges from the surfaces of webs of dielectric materials

摘要

An apparatus for the removal of charges of static electricity from the surfaces of a travelling continuous web of dielectric material, e.g. threads of synthetic fibres, comprises a closed tubular member disposed transversely of and adjacent to the travelling web and having an electrically conductive wall pervious to gas in the area thereof immediately adjacent to the travelling web, means for continuously feeding gas under pressure to the interior of the tubular member whereby gas is continuously forced through the pervious area to maintain a blanket of gas of predetermined thickness between the surface of the tubular member and the web travelling thereover, and a low resistance electrical conductor connecting the electrically conductive wall to earth. The electrically conductive wall may be a wall of sintered metal, e.g. sintered bronze or a porous carbon. The tubular member may be cylindrical. In the use of air spreaders employing air emission from the gas pervious passageways in the wall of sintered metal tubular film web guides to remove longitudinal wrinkles from the travelling web, it is found that direct earthing of the guide with a very low resistance conductor (such as a heavy copper wire) in accordance with the invention causes static charges to be completely removed from the web but that the usual earthing of the guide achieved by mounting the guide on the steel framework of the machine is not adequate to effectively neutralize the charge on the web.