Function and advantages
The continuous shear roll mill SRM is an open twin-screw extruder originating from the plastic industry for continuous mixing and homogenization.
It has been redesigned and most suitably adopted for the processing of solventless multibase propellants. Other applications in the propellant and explosives industry are presently under intensive development.
The main advantages of the continuous open shear roll mill are:
- Continuous production
- High production flexibility
- Remote control
- Only small quantities of intermediate products in one room, resulting in a high degree of safety
- High effectiveness of process
- The open construction permits a continuous optical observa- tion of the process
- The operation method permits at any time to control and change the parameters
Two horizontal rollers with spiral and – if required – longitudinal grooves operate in a counter rotational direction in order to transport the product continuously from the feeding side to the discharge side.
The transport of the product is effected by the helical shearing grooves in the rolls’ surface. Both rolls are individually heatable, disposing of two heating zones, and the temperature is adjustable in all 4 heating zones from 5 °C to 120 °C. Only 2 - 5 kg of the product are in the continuous process at one time, depending upon the type of SRM.
Gap pressure, friction, retention time and temperature are the variable parameters which are individually adjustable. These are the decisive factors that ensure an excellent homogenization and gelatinization of the product.