Proper use of muffle furnaces increases laboratory efficiency
Precautions for the use of muffle furnace
1. It should be placed on flat ground or on a concrete platform. It is better to pad the base of the furnace with an asbestos board to prevent the countertop from overheating. The controller should avoid vibration, and the location should not be too close to the electric furnace to prevent overheating and preventing the electronic components from working properly.
2. According to the rated voltage of the muffle furnace, configure plugs, sockets, fuses, etc. with appropriate power. The furnace shell and the controller shell are connected to the ground wire, and a thick rubber sheet is laid on the ground in front of the high-temperature furnace to avoid danger and ensure safety. The thermocouple should be inserted into the center of the furnace, and the gap between the hole and the thermocouple should be filled with asbestos rope. It is best to use compensation wires (or insulated copper core wires) to connect the thermocouple and the controller and be careful not to connect the positive and negative poles incorrectly.
3. When the muffle furnace is used for the first time or after a long period of inactivity, it must be pre-baked. Different models of muffle furnaces have different oven times.
4. When burning or melting the sample in the muffle furnace, the sample must be placed in a high-temperature-resistant porcelain crucible or porcelain dish, and the operating conditions must be strictly controlled to prevent the sample from splashing due to excessive temperature. Corrosion and bonding of the hearth. An asbestos board is placed at the bottom of the furnace, and the slag, metal oxides, or other impurities on the asbestos board should be cleared in time to protect the smoothness and cleanliness of the furnace.
5. The silicon carbon rod used in the resistance furnace of the muffle furnace ages naturally during use, and can be adjusted to the highest level step by step. If the heat generation is insufficient (that is, the power does not reach the rated value), the silicon-carbon rod should be replaced with a new one.
6. When putting crucibles, crucible racks, and other items into the furnace, do not touch the thermocouple, because the hot junction of the thermocouple extending into the furnace is easy to break under high temperature. After the burning is completed, the power supply should be cut off immediately, but the furnace door cannot be opened immediately, so as to avoid the furnace chamber from breaking due to sudden cold. Generally, a small slit is first opened to make the furnace temperature drop quickly, and then the furnace door is opened, and the burned object is taken out with crucible tongs.
7. The voltage must be gradually increased to increase the temperature, and the furnace temperature must not exceed the maximum temperature to avoid burning the heating element. Always look after it during use to prevent accidents such as burning of the furnace wire due to failure of automatic control. After use, cut off the power supply and close the furnace door to prevent the furnace chamber from being corroded by moisture.
8. No flammable and explosive materials should be stored around the muffle furnace, and no explosive dangerous materials should be burned in the furnace.
