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　　Some people say, Medium-frequency furnace Using it poses certain risks—actually, any equipment carries some degree of risk. However, the typical level of risk often stems from the equipment itself not being sufficiently well-designed or manufactured. So, is the safety of medium-frequency furnaces guaranteed? Let’s first take a closer look at what medium-frequency furnaces are.

　　Medium-Frequency Furnace Protection System:

　　1. Medium-frequency furnace cooling water system

　　The medium-frequency power supply, induction coils, water cables, and other components all require water cooling; therefore, water is essential to the operation of furnace equipment. The risk of damage to furnace equipment caused by cooling-water failures is relatively high. Since most of the components being cooled are energized—such as thyristors, induction coils, and water cables—the conductivity of the cooling water directly used to cool these components must be lower than the specified value. Additionally, the connecting hoses should be carbon-free rubber hoses. Furthermore, the inlet temperature, outlet temperature, water pressure, and flow rate of the cooling water must all comply with the design specifications. The cooling-water system of a medium-frequency furnace is equipped with various sensors to monitor the relevant parameters of the cooling water. If any cooling-water parameter deviates from the norm or exceeds the set values, an alarm will be triggered, or the equipment operation will be automatically halted.

　　 Medium-frequency furnace The cooling water pump station shall be equipped with two identical main pumps (one in use and one on standby), as well as an emergency cooling water system. When the power supply from the grid is interrupted and the main pumps fail to operate, the emergency cooling water system can provide cooling to the furnace body, thereby preventing damage to the furnace.

　　2. Medium-frequency furnace hydraulic system

　　The hydraulic system of the medium-frequency furnace is used for tilting the furnace to pour out the molten metal, as well as for opening and closing the furnace lid. To ensure reliable operation, the hydraulic station of the electric furnace should be equipped with two identical main pumps—one serving as the primary pump and the other as a standby. A throttling valve must be installed at the inlet end of the tilting furnace’s hydraulic cylinder to prevent the furnace body from suddenly dropping due to a loss of pressure in the hydraulic system. In the event of a prolonged power outage, the molten metal inside the electric furnace may cool down and solidify, potentially damaging the furnace lining. It would be extremely dangerous to attempt to melt the solidified metal by running the furnace itself; therefore, the electric furnace’s hydraulic system must be equipped with an emergency backup system. When the power supply is interrupted, this emergency system can be activated—if necessary—to pour out the molten metal from the furnace, thereby preventing it from solidifying inside.

　　3, Medium-frequency furnace Grounding and Furnace Leakage Monitoring Alarm

　　During the operation of a coreless medium-frequency furnace, damage to the furnace lining can lead to furnace leakage accidents. If molten metal leaks through the furnace lining, it can damage the insulation of the induction coil, the coil supports, and the magnetic yoke. If such leakage is not detected promptly, it could result in severe damage. Moreover, if the molten metal burns through the copper tubing of the coil, the water inside the tubing could come into contact with the molten metal, potentially causing an explosion and leading to a serious accident. Therefore, it is absolutely essential to install a furnace lining leakage alarm system. A DC circuit can be connected in parallel with the AC power supply circuit of the induction coil. The molten metal inside the furnace is grounded through the furnace bottom, while the induction coil is connected in series with the DC power source and a milliammeter, and all are grounded as well. Thus, the molten metal, furnace lining, induction coil, and milliammeter form a complete DC circuit. When the furnace lining is in good condition, its resistance is very high, so the milliammeter displays a very small reading. However, if the furnace lining deteriorates and molten metal starts leaking into the lining near the induction coil, the resistance of the lining will decrease, causing the milliammeter reading to increase significantly. Once the current value exceeds the preset threshold, an alarm will be triggered and the main power supply will be automatically cut off, thereby effectively preventing furnace leakage accidents from occurring.

　　4. Automatic Fault Diagnosis for Medium-Frequency Furnaces

　　Modern medium-frequency furnaces are equipped with a computer-based management system. This system features automatic fault-diagnosis capabilities. It scans all the setting points of the equipment, and when it detects abnormal parameter values at any setting point, it immediately triggers an alarm and can display and record detailed information about the fault. Thanks to its rapid scanning speed—up to hundreds of scans per minute—the system is able to identify faults in their very early stages, thus preventing them from causing severe damage to the equipment. Information related to any detected faults is stored in the computer for future reference.

　　In addition to those listed above, Medium-frequency furnace There are also other safety measures in place—for example, when the cabinet door of the medium-frequency furnace power supply is opened, a mechanical interlock will automatically disconnect the incoming power supply. Another example is that each capacitor is equipped with a pressure switch: if the internal pressure of a capacitor exceeds the preset value, an alarm will be triggered and the power supply will be cut off, thereby preventing the capacitor from exploding due to excessive internal pressure.