Is ultrasonic spot welding machine harmful to human body? Wear anti-radiation clothes effective

Ultrasonic waves and infrasound are human ears can not hear but your nerves will feel, long-term harmful to the human body, short-term harmless. For example, in the metal welding ultrasonic flaw detection staff to wear protective clothing, other personnel must be in a circle 40 meters away.

Sound frequency greater than 20,000 Hz sound waves called ultrasound, which is widely used in various fields of industry, such as medical ultrasound is a kind of ultrasound, in addition to medical surgery in the ultrasound emulsification technology is for the body of the effective surgical methods of stone. You can't simply say that it is harmful or not, it all depends on his energy output rate, in the low energy it is beneficial, in the high energy it can be used as a murder weapon.