What we commonly use in our daily life is dry powder fire extinguishers, which spray white powder on the fire to extinguish the fire, but the dry powder will scatter everywhere and have an unpleasant smell. Although ultrasonic fire extinguishers are nothing new, their equipment is bulky, bulky and costly, making it difficult to be widely used at present. Two students from George Mason University in the United States developed a small ultrasonic fire extinguisher that weighs only 20 pounds and most importantly costs only $600. The device consists of a large speaker and a portable terminal. The ultrasonic frequency emitted is 30- Low frequency waves between 60HZ. At present, the invention is still in the prototype stage and can only extinguish some small fires. There are still many technical problems that need to be overcome.
