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Author
Dehart, M. G. | Musser, D. A. | Krajkowski, E.
Title
Elimination of Rolled Powder Fires. Phase 2. Final Report. March 1991-March 1992..
Coporate
Hercules Inc., Radford, VA
Report
ES-1AA-6-855364; ARAED-CR-92003, September 1992, 248 p.
Distribution
AUTHORIZED TO U.S. GOVERNMENT AGENCIES ONLY
Contract
DAAA-09-77-C-4007
Keywords
powders | propellants | carbides
Identifiers
roll fires; solventless propellant; propellant paste; rool mills; prerolls; evenspeeds
Abstract
This project was tasked to investigate equipment and/or process changes in solventless propellant manufacture to eliminate, if possible, rolled powder fires. It was previously determined that the majority of fires are caused by adiabatic compression of gases trapped in blisters, wrinkels, and folds of the propellant sheets during rolling. This mechanism of propellant ignition was investigated, and it was determined that ignition occurred primarily between 70 and 130 seconds of rolling. Reducing the preroll speed by 1/3 during this "critical fire window" resulted in no fires. In addition, detailed studies were conducted to investigate an alternate roll cleaning material, an experimental roll polishing machine, and a nickel and tungsten carbide coated roll for the preroll mills. Implementation of the equipment and process changes recommended as a result of these studies could potentially reduce all process oriented preroll fires to virtually zero.