A Novel Device for Optical Imaging of Blast Furnace Burden Surface: Parallel Low-Light-Loss Backlight High-Temperature Industrial Endoscope

Accurate real-time optical imaging of the burden surface shape plays an important role in improving the gas flow distribution, reducing the coke ration, and reducing the emissions of a blast furnace. To overcome the high-temperature, high-dust, and lightless environment and obtain clear images of the burden surface, a parallel low-light-loss backlight high-temperature industrial endoscope is developed. The design of a parallel low-light-loss backlight path and a high-light-efficiency, low-light, color backlight source overcomes the lightlessness issue. Combined with the endoscopic optical imaging method, a high-temperature resistant image-capturing lens and a high-temperature non-resistant photosensitive chip are separated at two ends of the instrument. This separation design method together with the water cooling and industrial nitrogen cooling system enables the equipment to overcome the high temperature issue. Moreover, a new installation strategy, which avoids the material flow and high-dust region, is proposed to overcome the high dust issue. The strategy includes establishing a trajectory model of dust particles to determine the low-dust area and conducting a landing points experiment and a trajectory model of the material flow to determine the no-material-flow region. The industrial experiment results indicate that the developed device obtains real-time images of the burden surface and exhibits clear details of the coke and iron ore particles. The application also demonstrates the validity and better imaging performance of the proposed method compared with conventional detection methods.