How to detect the lining thickness of high temperature electric furnace?
Time：2020-11-06 09:14 Click：
Furnace lining refers to the furnace wall of the furnace, which is made of high temperature resistant ceramics. The service life of the high-temperature electric furnace lining directly affects the overall service life of the high-temperature electric furnace. So, how to detect the thickness of the lining of a high-temperature electric furnace?
1, capacitance method
The capacitance method is similar to the resistance method. A coaxial circular capacitor sensor is embedded inside the furnace lining. The capacitance value corresponds to its length. The thickness of the blast furnace masonry can be determined by measuring the capacitance value.
2, stress wave method
The stress wave signal is highly sensitive to structural defects. When the stress wave propagates in the medium, such as holes, cracks and other interface discontinuities, reflection, refraction, scattering and mode conversion will occur, using the characteristics of the stress wave The thickness of the stave material can be determined.
3. Resistance method
The resistance element is embedded in the furnace lining, and the front end of the sensor is aligned with the inner surface of the furnace lining. The resistance value of the resistance element is related to its length. As the resistance element and the furnace lining loss synchronously, the resistance will change. Use the corresponding measurement The meter measures the electrical signal output by the component, and then the remaining thickness of the furnace lining can be measured online.
4, heat flow detection method
According to thermodynamics, temperature difference, thermal conductivity and furnace wall thickness determine the heat flow intensity. For blast furnace lining, the thermal conductivity is fixed, and the furnace wall thickness can be obtained from the temperature difference and heat flow intensity.
The heat flow detection sensor is installed in the lower temperature part of the furnace lining. The heat flow intensity is calculated through the water temperature difference of the cooling wall of the hearth, and then combined with the temperature value measured by the thermocouple in the brick lining to calculate the thickness of the furnace wall.
5. Ultrasonic method
is the use of the characteristics of ultrasonic propagation in solid media for thickness measurement. At a certain temperature, ultrasonic waves are incident on the furnace lining and enter the furnace, and the propagation time of ultrasonic incident and reflection in the furnace lining is used to obtain the residual thickness of the furnace lining.
6. Multi-head thermocouple method
is to install several thermocouples of different lengths in a protective sleeve, and then install them in the brick lining to be inspected, and infer the erosion of the masonry by measuring the temperature change of each thermocouple. When the temperature of each point and the temperature gradient between each point are basically stable, when the brick lining is gradually eroded to a certain part, the galvanic couple in that part will be destroyed and the temperature signal will be abnormal.
7. Model inference method
is the use of thermocouples as detection elements, the application of thermodynamics and other theories to establish a mathematical model of the hearth and bottom temperature site, through software programming and numerical analysis methods, the approximate location of the molten iron solidification line and carbon brick erosion line can be calculated.