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Regarding ultrasonic descaling equipment and the corrosion that occurs during the descaling of heat exchangers, ultrasound functions by converting electrical energy into magnetic energy and then into mechanical energy. The principles of descaling are as follows: 1. Shear effect – due to the different elastic coefficients of the pipes, the scale, and water, the amplitude of vibrations varies, which leads to the formation of cracks and gaps between them, eventually causing the scale to fall off. During this process, the pipeline is also subjected to continuous reciprocating vibrations, which causes stress corrosion or cracks to occur in those parts of the pipeline that are more vulnerable or under greater stress. 2. Ultrasonic cavitation (cavities) – this is also considered an effective aspect of ultrasonic descaling. The principle is that ultrasonic waves generate a large number of bubbles and voids during operation; the formation and collapse of these bubbles and voids create intense, large-amplitude oscillations in the water, which are transmitted throughout the pipeline, thereby preventing scale from accumulating on the pipe walls. But this same cavity gives rise to another problem: cavitation. Cavitation is most commonly encountered in water pumps and propellers. As the impellers of these devices rotate, a negative pressure is created at the inlet; once this reaches the cavitation threshold, a large amount of gas is generated. This gas then disappears, and during this process the space occupied by the bubbles is filled back with water, resulting in powerful shock waves similar to those caused by water hammers. Over time, these shock waves cause severe erosion of the impellers and propellers. I hope experts with similar or different opinions can come together to discuss this issue