The role of ultrasonic equipment in liquids is achieved through cavitation, so the greater the ultrasonic energy, the stronger the cavitation effect, and the greater the noise generated. From another perspective, the higher the noise, to some extent, it actually indicates that the equipment power is higher.
Of course, noise must be controlled. As noise is a byproduct of cavitation, we cannot reduce it by reducing cavitation. Therefore, we can only control noise by cutting off or blocking the transmission path of noise.
Internationally, the following requirements are put forward for noise control. In 1967, the International Organization for Standardization recommended using A sound level as the noise standard to adapt to the widespread use of A sound level as a noise evaluation indicator in various countries. This standard proposed that workers work 8 hours a day in a noisy environment, and the A sound level of continuous noise is allowed to be 90 decibels; For every half of the time, the sound level can be increased by 3 decibels, but in no case should it exceed 115 decibels. In 1971, ISO proposed a hearing protection standard based on the equivalent sound level L when there are fluctuations in sound levels. The protection standard was proposed as L=90 decibels, and workers who work in a 90 decibel noise environment for a long time still have the possibility of hearing loss. Currently, there is debate internationally on using 90 or 85 decibels as hearing protection standards. In summary, the proposal of noise standards is mainly aimed at protecting the human hearing system. Here, we use 85 decibels as the noise standard, Currently, we can protect a person’s hearing system through the following methods:
- Operators should wear soundproof earplugs, most earplugs in the market can generally reduce noise by 40 decibels.
- Adding remote control to the ultrasonic system can effectively reduce the chances of personnel coming into close noise, thereby cutting off the impact of noise.