The new technology of radar measurement of molten steel level detection

Radar technology is no stranger to ordinary people. In the military, radar is often used to measure the height of flying objects. The radar antenna emits a beam of microwave signals, and the microwaves will be reflected by the clouds and aircraft, and then received by the radar antenna. Due to the difference in the material and density of clouds and aircraft, the reflected signals produced are different. The use of computer recognition technology can clear radar technology, which is not unfamiliar to ordinary people. In the military, radar is often used to measure the height of flying objects. The radar antenna emits a beam of microwave signals, and the microwaves will be reflected by the clouds and aircraft, and then received by the radar antenna. Due to the difference in the material and density of the cloud and the aircraft, the reflected signals produced are different. Using computer recognition technology, the cloud and the aircraft can be clearly distinguished. The application of radar technology to industry to measure the molten steel level of ladle and mold has been developed in recent years with the development of radar technology and the increasingly high requirements for measurement technology in the industry. The use of radar measurement technology to detect the level of molten steel is actually radar ranging. The radar antenna sends out a beam of microwave signal, which will be reflected when it reaches the reflecting surface. The radar determines the distance between the antenna and the reflecting surface by measuring the delay between the transmitted wave and the reflected wave. Because the microwave measurement is not affected by the environment and is very stable, theoretically it can be measured very accurately. In military radar ranging, because the distance is large, a beam of signals is emitted, and it takes a long time to return after reaching the object, so the measurement is relatively simple. If it is used to measure the molten steel level, especially the molten steel level of the mold, the distance between the radar antenna and the molten steel level will not exceed 1 meter, and the delay between the transmitted wave and the reflection technique will be extremely short, making the test very difficult. In recent years, due to the rapid development of microwave measurement technology and computer technology, it is possible to use radar technology to detect the molten steel level of the mold and the tundish. At present, the MIWIS radar liquid steel level detector newly launched by Canada Jiachuang Company in mainland China has a measuring range of 0.2 to 20 meters, and its liquid steel level detection resolution has reached 1 mm. Radar liquid steel level detection system Radar liquid steel level detection system consists of horn antenna, radar signal transmitting and receiving unit, computer processing unit and display unit. When detecting the molten steel in the mold, the antenna of the radar measurement system emits a microwave signal, which is reflected after reaching the molten steel surface of the mold, and then received by the horn antenna, processed by the signal transmitting and receiving unit, and processed by the computer Later, it can provide analog or digital output signals to the molten steel level control system, or the signals can reach the display unit for level display. In fact, the measuring system can be installed with a bracket beside the mold or in the lower part of the tundish. The measurement system and the horn antenna have an air-cooled system to ensure normal operation under long-term high-temperature baking. The characteristics of the radar mold molten steel level measurement system. During the continuous casting of molten steel, the working environment above the mold is very harsh. At present, the eddy current detection method is mostly used for the detection of bloom and slab mold liquid level. Due to the detection characteristics of the eddy current probe, the probe is not more than 100 mm away from the molten steel surface. If steel overflow occurs, it is easy to cause damage to the probe. The distance between the antenna of the radar measurement system and the molten steel can accurately measure the molten steel level from 200 mm to 20 meters, so the test system can work very safely. The radar antenna is a radar signal in the form of a beam, and the echo signal reflected back is still received by the antenna. By measuring the transmission time of the radar microwave pulse signal from transmission to reception, the distance from the horn antenna to the molten steel surface can be calculated. Therefore, the biggest advantage of using radar technology to measure the molten steel level is that it does not need to be calibrated. As long as the installation is stable, the molten steel level can be accurately measured. The radar measurement range is very large, and it can accurately measure the molten steel level of the entire mold height, which cannot be reached by any other mold level detection device. Radar measurement can meet the needs of automatic pouring, but automatic pouring cannot be performed using eddy current probe measurement. Usually, during continuous casting of molten steel, there is a layer of protective slag on the surface of molten steel. The microwave signal emitted by the antenna will also be reflected when it encounters the mold powder. Because the density and surface smoothness of the mold powder are very different from those of molten steel, the reflected signal will also be very different. Through the signal recognition unit of the MIWIS radar measurement system, the reflected signal of the molten steel level can be distinguished, and the purpose of accurately measuring the molten steel level of the mold can be achieved. The MIWIS radar liquid steel level measurement system of Canada Jiachuang Company has two horn antennas, one of which is a microwave antenna and the other is an infrared temperature probe. During normal casting, for a certain steel grade, the temperature of molten steel in the mold is basically a fixed value, but the thickness of the mold slag increases, and the temperature of the mold slag surface will decrease. Through the temperature difference detected by the infrared temperature probe, the thickness of the protective slag can be calculated. Therefore, the MIWIS radar molten steel level measurement system can accurately measure the thickness of the protective slag, and provide analog or digital signal output for the automatic slag adding machine to work. Because the MIWIS radar liquid steel level measurement system is particularly convenient to install and has a large measuring range, some steel plants are also used to detect the liquid steel level of the tundish car.