Defrosting control device

Abstract

Abstract PURPOSE: To avoid the overheating during defrosting and to eliminate the defrosting completion timer by arranging such that a heater or a part of a heater is made into a positive-characteristic thermister with a large positive temperature coefficient of resistance. CONSTITUTION: A circuit is formed of heater 2 having a positive characteristic thermister element with a very large positive temperature coefficient of resistance, switching element 3, which controls the heater, control circuit 4, which gives the switching element control signals, and sensor 5, which detects the current in the circuit. Switching element 3 is set ON by the signal from the control circuit, current flows in heater 2, and heat is generated, and thereby defrosting starts. The heat generated during the time of defrosting is absorbed by frost, and thus the temperature rise in the heater is checked but the temperature rises on completion of defrosting. As a result of this temperature rise, resistance increases sharply, and the current decreases and the heat generation is reduced. In this way, the excess heating after completion of defrosting is prevented without using a defrosting completion sensor. COPYRIGHT: (C)1979,JPO&Japio

Inventors

• 👤 Ryoichi Fujimoto
• 👤 Kazuo Takasugi

Bibliographic Details