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 FIRE. THE DUST CLOU D WAS IGNITED WHEN IT TRAVELED INTO THE COMBUSTION CHAMBER AND CAME IN CONTACT WITH SMOLDERING ORGANO CLAY THAT HAD BEEN HEATED BY COMBUSTION BURNER FLAME.A VALVE BETWEEN THE CHAMBER AND DRYE