| 摘要 |
PROBLEM TO BE SOLVED: To provide a defrosting heater which prevents inflammable refrigerant from catching fire even in the case that defrosting operation is carried out under an environment where leakage of the refrigerant occurs. SOLUTION: The defrosting heater is constituted of first glass tube 53, second glass tube 54 installed so as to cover the outer circumference of the tube 53, a heater wire 52 comprised of a metal resistive element which is installed inside the first glass tube 53, a stopper 58 blocking up openings of both ends of the first glass tube 53 and the second glass tube 54, and a lead wire 55 penetrating the stopper 58 and being connected to an end of the heater wire 52. A connection part of the heater wire 52 and a code 55 is provided with a positioning plate 57 which is held by the stopper 58 and which prevents the connection part from deviating. The size of clearances 58b formed by the stopper 58 and the positioning plate 57 is arranged in accordance with an amount of the trapped inflammable refrigerant and a surface temperature of the heater wire 52 during current-carrying to the heater wire 52. Therefore, since flame is not propagated, safety is kept at all times.
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