EXTRUDER AUTOMATIC CONTROL Russian patent published in 2011 - IPC B29C47/00 

FIELD: process engineering.

SUBSTANCE: invention relates to food industry, namely, to automation of vegetable- and animal-origin stock. Proposed method comprises measuring stock pressure and temperature in pre-matrix zone, consumption and moisture content of stock and extrudate at vacuum chamber outlet, heat carrier temperature and flow rate in extruder jacket, vacuum chamber pressure, temperature and flow rate of evaporated moisture derived from vacuum chamber to condensation, extruder drives and vacuum pump output being adjusted. Moisture evaporated from product is condensed in refrigerator steam ejector machine chill receiver. Said machine doubles as condenser operated in closed thermodynamic cycle. Heat is transferred from cooling water to moisture evaporated from product via chill receiver surface separation wall. Note here that steam generator is used to force steam at 0.8-1.0 MPa into ejector nozzle to create lower pressure of 0.0009-0.001 MPa and temperature of 4-7°C in evaporator with coolant circulating via chill receiver. Formed mix of coolant vapors and operating steam is forced in extruder jacket downstream of ejector at 0.2-0.3 MPa. Note here that one portion of water condensate is fed into evaporator to replenish waster stock while another portion, together with condensate, is fed, first, into condensate collector and, then, into steam generator to produced closed-loop process. Note also that water level and steam generator and evaporator pressure are measured, as well as working and ejected steam flow rate, coolant temperature at chill receiver inlet and condensate temperature at chill receiver outlet. Besides, coefficient of heat transfer from coolant to condensed moisture via chill receiver cooling surface by current coolant temperature at chill receiver inlet, evaporated moisture flow rate and temperature and condensate temperature at chill receiver outlet. Current ejection factor related to relation between flow rate of ejected steam and heat flow of evaporated moisture to define coolant flow rate in recirculation circuit "chill receiver - evaporator" with correction by heat transfer factor. Note that with heat transfer factor decreasing from preset range, ejection factor is increased by increasing working steam flow rate. Note that with heat transfer factor increasing from preset range, ejection factor is decreased by decreasing working steam flow rate Heat flow of aforesaid mix is used to correct flow rate of initial stock into extruder. Water level in evaporator and steam generator are stabilised by acting on condensate flow rate in evaporator and stem generator. Note here that with steam generator pressure exceeding preset tolerance, safety valve effects pressure release.

EFFECT: higher accuracy and reliability of control, reduced power consumption, higher quality of extrudate.

1 dwg, 2 tbl, 1 ex