ELECTRIC HEATER CONTROL PROCESS

摘要

FIELD: controlling electric heaters. ^ SUBSTANCE: proposed control process for electric heaters connected to power supply mains using control unit includes serial push-pull turn-on cycles for electric heater at temperature below desired value and its turn-off cycle at temperature equal to or higher than desired value. Electric heater power is regulated by full-power connection of heater during first cycle in case temperature under control is below desired value and its disconnection if temperature is equal to or higher than desired value; electric heater power is set at each step of next cycles with temperature below desired value to equal sum of mean heater power in preceding cycle and first power correction affording stability margin in case of variations in external disturbances in the form of heat loss; at temperatures higher than or equal to desired value it is set to equal difference between mean value of electric heater power in preceding cycle and second corrected power affording stability margin of control process in case of variations in external disturbances in the form of heat supply at temperature variations exceeding admissible limits; control is effected from first cycle whose second step involves heater power setting at temperature below desired value equal to sum of mean heater power within cycle preceding initiation of first cycle and first power correction; at temperature equal to or higher than desired value it is set to equal difference between mean heater power in cycle preceding origination of first cycle and second power correction. ^ EFFECT: enhanced reliability of heated medium temperature control. ^ 1 cl, 2 dwg