A VACUUM PNEUMATIC PROCESS FOR FILLING LARGE DRY CHEMICAL FIRE EXTINGUISHERS

Abstract : A pneumatic conveying system was developed for filling large fire extinguishers with dry chemical powder. The system is intended particularly for air stations and similar field establishments; it could even be used for reloading extinguishers at the site of a fire. The essential components are a 1-1/2 horsepower vacuum cleaner and an especially designed device which is used in place of the extinguisher fill cap which separates the powder from the air stream, and also provides entry for a powder level gage stick. In trials at the Laboratory this system reduced the filling time for a 400-lb. capacity dry chemical air lift extinguisher from 46 to 6 minutes, reduced dusting to a negligible amount, and allowed correct gaging of adequate charge amounts.