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United States Patent 4931229
Douris , ê et al. June 5, 1990

Method and apparatus for protecting a screw extruder producing strand-shaped explosives and propellants

Krimmel , Ê et al. June 5, 1990

Abstract

A method and apparatus for protecting a mixing apparatus for producing strand-shaped explosives and propellants in a twin-shaft screw extruder, the housing of which is formed of housing parts connected to a clamping device acting under hydraulic pressure. In order to compensate for excessive pressure and to prevent abrupt opening of the mixing chamber, the torque developed at the screw shafts is continuously monitered and fed to a control and storage device together with temperature and pressure values measured at the end of the screw shaft in the material being processed. If one of the measure values exceeds a permissable limit, a signal is produced to change the operating condition of the screw extruder, particularly to stop and withdraw the extruder from the housing, to halt the drive motor of the extruder shafts and to open the extruder housing by relieving the clamping device.