Twin Screw Extruder With Black powder
A continuous process of manufacturing black powder using a twin screw extruder is disclosed. Guar gum mixed with the single screw extruder at a concentration in the range from 0.05% to 0.5%, by weight, dramatically reduced the friction in the dies and permitted extrusion of the powder at much lower water levels. Different size dies used in combination with face cutting of the extruded strands produce various sized granules. The process can be operated remotely and automatically. The process reduces the number of buildings, equipment and personnel required to manufacture black powder or black powder substitute. The process produces more uniform and reproducible particle sizes.
The present sheet production extruder is directed to a continuous process of manufacturing black powder and black powder substitute using a twin screw extruder. Previous attempts at processing black powder with an extruder, using water as a processing aid, failed because the composition could not be extruded at the required density. High friction in the dies prevented extrusion.
Applicants found that a guar gum processing aid at a concentration in the range from 0.05% to 0.5%, by weight, dramatically reduced the friction in the dies and permitted extrusion of the powder at much lower water levels. Other materials similar to guar gum, such as karaya gum and gum tragacanth, can be used in the present invention and are to be included within the scope of guar gum.
Different size dies used in combination with face cutting of the extruded strands produce various sized granules. The process can be operated remotely and automatically. The process reduces the number of buildings, equipment and personnel required to manufacture black powder or black powder substitute. The process produces more uniform and reproducible particle sizes.
Referring to the current batch process described in the Background section, above, steps 4-8 of blocking, breaking, milling, screening, and drying are replaced according to the present invention by the metering of ingredients into the twin screw extruder, compounding, extruding, face cutting, and drying. These steps according to the present single screw extruder can be automated and performed remotely without direct personnel control. This results in a safer process to personnel and equipment and to a more predictable, homogeneous twin screw extruder.