Environmental control of bushing

摘要

A method and apparatus for eliminating short term yardage variation in the formation of glass filaments is disclosed. This method involves additionally cooling the bushing tips from which molten glass is drawn to form filaments utilizing a separate cooling means in addition to the fin coolers normally employed. The additional cooling means removes heat at a rate of from about 1,000 Btu's per hour to about 3,000 Btu's per hour (293 to 879 watts) based upon a drawing rate of about 35 to about 70 pounds of glass per hour (77 to 154 kilograms per hour). The method further involves either forming a controlled stream of air across the bushing tips from above the additional cooling means or preventing the direct impingement of air upon bushing tips by blocking the air with the additional cooling means, to provide a more stable thermal environment under the bushing.