I am often asked, since more than the human ear can hear the range of sound waves called ultrasonic, then why in the ultrasonic cleaning machine work, why we can still hear such a harsh noise?
The reasons are as follows.
1, ultrasonic cleaning sound is mostly generated by ultrasonic cavitation, so also called “cavitation noise”. As long as the use of cavitation effect to clean, cavitation noise is basically inevitable, it must be accompanied by the cavitation effect occurs and generated.
Simply put, cavitation noise is generated: ultrasonic waves in the water to produce ultrasonic cavitation, cavitation bubble closure will produce fundamental harmonics (consistent with the ultrasonic frequency f0) and sub-frequency harmonics (1/2f0, 1/3fo …), these harmonics are superimposed together to form a cavitation noise, where the frequency of sub-frequency harmonics is low, it is possible to enter the human ear can hear the frequency Within the range, become the main source of sound emitted during ultrasonic cleaning. The lower the ultrasound frequency, there are more cross-frequency harmonics can be heard, so the louder the sound.
2, the other part of the sound from the vibration of the cleaning tank. Most of the ultrasonic cleaning machine manufacturers will be in the bottom of the cleaning tank directly bonded ultrasonic transducer, one because the cost is lower, the second is easier to dissipate heat, which will lead to ultrasonic vibration directly on the tank, not only will produce more noise, but also accelerate the fatigue of the tank, causing leakage of welds, cracks in the tank and other problems. So professional manufacturers prefer to use the input type or vibration plate type of ultrasonic installation.
