METHOD OF EXTRUDER AUTOMATIC CONTROL Russian patent published in 1999 - IPC

FIELD: food industry. SUBSTANCE: method may be used for automation of biopolymer processing. It may also be used in devices intended for manufacture of extruded products. Method includes measurement of operating member torque and material temperature at extruder output in prematrix zone. Moisture content and consumption of raw material, heating or cooling agent flow rate, extrudate consumption and moisture content, material pressure in premature zone, as well as power of extruder controlled drive are measured additionally. Rotational speed of extruder worm feeder is determined by measured values of raw material consumption and moisture content. Heating or cooling agent flow rate is determined by material temperature in front of matrix. Control mode is corrected by current value of extrudate final moisture content. If final moisture content of extrudate deviates from preset value towards increasing control mode on first control level is corrected, that is rotational speed of worm feeder is increased till maximum permissible value of material pressure in prematix space is obtained. Then second control level is initiated according to which heating agent flow rate is increased till maximum permissible value of temperature is obtained. If final moisture content of extrudate deviates from preset value towards decreasing rotational speed of extruder worm feeder is reduced till minimum permissible value of material pressure in prematrix space is obtained (first level of control). Then second level of control is initiated according to which heating agent flow rate is decreased till minimum permissible value of temperature is obtained. Value of total power and material consumption cost which falls on unit of obtained product mass is calculated continuously processing from measured values of raw material consumption, heating or cooling agent flow rate and power consumed by extruder controlled drive. Sign of this value derivative is determined by raw material consumption. The sign is used to render effect on initial product consumption in antibate dependence. Method makes it possible to improve extrudate quality. EFFECT: reduced material and power consumption. 1 tbl, 2 dwg