WHILE PERFORMING TROUBLESHOOTING PROCEDURES ON FLUID BED DRYER, ORGANO DUST SUSPENDED IN THE FILTER SOCK, DISLODGED, CAUSING A DUST CLOUD OF PROPER CONCENTRATION TO SUSTAIN A FIRE. THE DUST CL OUD WAS IGNITED WHEN IT TRAVELED INTO THE COMBUSTION CHAMBER AND CAME IN CONTACT WITH SMOLDERING ORGANO CLAY THAT HAD BEEN HEATED BY COMBUTION BURNER FLAME. A VALVE BETWEEN THE COMBUSTION CHA