Construction and operating performance of apparatus for rotating irradiation fiber curing

Apparatus for rotating irradiation fiber curing was designed and constructed for the radiation curing on the synthesis of heat resistant silicon-carbide fiber from organic polycarbosilane fiber. The radiation curing of organic fiber was carried out by high energy electron beam irradiation under helium gas flow atmosphere by rotating fiber bobbin during irradiation. The trapped radicals in the fibers by irradiation were diminished by heat treatment in inert gas in order to prevent oxidation after irradiation in air. This apparatus is composed of irradiation fiber bobbin, irradiation chamber, heat treatment vessel, adiabator insertion box, and evacuation systems. irradiation chamber and heat treatment vessel have the airtight shutters, and the fiber bobbin is transfered from irradiation chamber to heat treatment vessel without any contact with air (oxygen). In order to decrease temperature rise of the sample by electron beam heating, helium gas cooling fins connected to water cooling pipe are provided in the inside wall of irradiation vessel. The dose of sample fiber on the bobbin is 7 kGy/mA min when 2 MV and 0.5 mA electron beam is irradiated under the bobbin rotation by 1 rpm. Using this apparatus, polycarbosilane fiber of maximum 5 kg can be cured by one time irradiation. The temperature inhomogeneity in the heat treatment vessel is enhanced at higher temperature, but heat treatment of sample can be homogenized by rotation during heat treatment. This apparatus is operated as the pilot plant for the design of industry plant. (author)