Defrosting control apparatus.

摘要

The accumulation of ice on a surface such as an evaporator fin (2) in a refrigerator unit is detected by a mechanical probe (4) which is moved by a bimetal bender element (8) upon periodic timer-controlled energisation of a bimetal heater (12) so as to pass over the surfaces of an evaporator fin (2). If the movement of the probe is obstructed by ice on the evaporator fin surfaces a switch (24) is operated by a bistable mechanism (16, 18, 19), causing energisation of a defrosting heater (25) and switching off the refrigerator compressor motor (C). If no ice is detected the probe (4) returns to its original reset position without operating the defrost control switch (24).