The function of the design in household refrigerators that uses heating tubes with dual fuses

The heating tubes in a refrigerator (such as defrosting heating tubes) are mainly used for: defrosting function: Regularly melting the frost on the evaporator to maintain the cooling efficiency. Prevent freezing: Maintain a slight heating in specific areas (such as door seals) to prevent condensate water from freezing. Temperature compensation: Assist in activating the temperature control system in low-temperature environments. Heating tubes are high-power components. During operation, they may pose risks due to overheating, short circuits or continuous power supply. Therefore, multiple protections are required.

The core significance of double fusesDouble fuses are usually a combination of temperature fuses (disposable) and resettable fuses (such as bimetallic strip fuses), and their functions are as follows: Firstly, they provide dual fault protection, the first line of defense (resettable fuses) : When the heating tube experiences an abnormal current due to a temporary fault (such as a brief overheating), a reset fuse (such as a bimetallic strip fuse) will disconnect the circuit. After the fault is eliminated, it can be reset automatically or manually to avoid frequent replacement. The second line of defense (temperature fuse) : If the resettable fuse fails (such as contact adhesion), or the heating tube continues to overheat (such as control circuit failure), the temperature fuse will permanently melt when the critical temperature (usually 70℃ to 150℃) is reached, completely cutting off the power supply to prevent fire or component burnout. Secondly, it is to deal with different types of faults, such as current overload: responded by resettable fuses. Abnormal temperature: Responded by the temperature fuse (it will still act even if the current is normal but the temperature exceeds the standard). Finally, redundant design enhances reliability. A single fuse may cause protection failure due to its own fault (such as failure to blow in time), while a dual fuse significantly reduces risks through redundant design.