Now muffle furnaces are widely used in the lab. The article mainly introduces how to select a high-temperature muffle furnace and precautions for the use of a muffle furnace.
Factors to be Considered for Choosing High-Temperature Muffle Furnace
1. Temperature
Select the Z high temperature of the muffle furnace according to the actual temperature. The Z high temperature of the muffle furnace is generally 100°C-200°C higher than the operating temperature.
2. Size
Select the appropriate furnace size according to the weight and volume of the sample to be burned. Generally speaking, the volume of the furnace is more than three times the total volume of the sample.
3. Power supply voltage
Before use, determine whether the voltage of the muffle furnace is 380V or 220V to avoid a wrong purchase.
4. Price
The price of the furnace is an essential factor to consider. It should fit your budget and offer value for money. However, it is also important to ensure that the furnace meets all the required specifications and quality standards.
5. Furnace material
The furnace material is generally divided into two types, which include fiber material and refractory brick material. The fiber material is light in weight, soft in texture, and good in insulation, while the refractory brick is heavy in weight, hard in texture, and general in insulation.
6. Heating element
According to the different requirements of sample burning, the furnace body is determined according to different heating elements. Generally, resistance wire is selected below 1200 °C, silicon carbide rod is basically used at 1300°C-1400 °C and silicon molybdenum rod is widely used at 1400°C-1700 °C.
Precautions for the Use of High-temperature Muffle Furnace
1. When the muffle furnace is just started to use or is used again after a long-term shutdown, it is necessary to dry the furnace. The oven temperature and time shall be 200°C to 200°C for four hours. During use, the furnace temperature shall not exceed the rated temperature to avoid burning the electric heating element. It is forbidden to pour various liquids and soluble metals into the furnace. In order to ensure safe use, it is necessary to install ground wire and ground it well.
2. The muffle furnace and furnace controller need to work in places where the relative humidity is not more than 85% and there is no conductive dust, explosive gas, or corrosive gas. When metal materials such as grease need to be heated, the volatile gas with big stars will affect and erode the surface of electric heating elements, destroying them and shortening the service time of the muffle furnace. Therefore, when heating, the container should be sealed in time.
The working life of the heating element depends on the oxide layer on its surface. Destroying the oxide layer will shorten the service life of the heating element and each shutdown will damage the oxide layer. Therefore, the shutdown should be avoided after startup.
4. The controller of a high-temperature muffle furnace shall be limited to use within the ambient temperature range of 0°C-40°C. Do not pull out the thermocouple suddenly at high temperatures to prevent the jacket from exploding.
5. When the muffle furnace is heated, the furnace jacket will also become hot. Keep the furnace away from inflammable and keep it easy to dissipate heat outside the furnace. Pay attention to safety and avoid scalding.
6. When using the furnace, take care of it frequently to prevent accidents caused by the failure of automatic control. Do not use the furnace when there is no one on duty at night.
7. After using the muffle furnace, cut off the power supply to make it cool naturally. The furnace door should not be opened immediately to avoid sudden cold cracking of the furnace. The furnace door should be opened only when the temperature drops below 200 ° C.
8. According to the technical requirements, regularly check whether the wiring of the electric furnace and controller is in good condition and whether the pointer of the indicator is stuck when moving. Adopt the potentiometer to calibrate the error of the instrument caused by magnetic steel, demagnetization, fatigue of the spring, and balance damage.
In conclusion, selecting the right high-temperature muffle furnace is crucial for achieving accurate and repeatable results in high-temperature applications. When choosing a furnace, it is important to consider factors such as temperature range, heating element, furnace size, control system, atmosphere control, safety features, and price. Additionally, it is important to follow proper operating procedures and safety guidelines when using the furnace to ensure its longevity and prevent accidents. With the right furnace and proper operation, high-temperature muffle furnaces can be valuable tools for a range of applications in industries such as materials science, chemistry, and engineering.
