人们解决了利用电子学技术产生超声波的办法，从此迅速揭开了发展与推广超声技术的历史篇章。 From the end of the 19th century to the beginning of the 20th century, after the piezoelectric effect and the anti-piezoelectric effect were discovered in physics, the ultrasonic level meter solved the method of generating ultrasonic waves using electronic technology, and it quickly opened the development and promotion of ultrasonic technology. Historical chapters. In 1922, the first invention patent for ultrasound treatment appeared in Germany. A literature report on the clinical effects of ultrasound treatment was published in 1939. In the late 1940s, the rise of ultrasound treatment in Europe and the United States, until the first international conference on medical ultrasound held in 1949, did not have the exchange of ultrasound treatment papers, laying the foundation for the development of ultrasound therapy. Many papers have been published at the 2nd International Conference on Ultrasound Medicine in 1956, and ultrasound treatment has entered a practical mature stage.
工作原理:超声波液位计的工作原理是由换能器(探头)发出高频超声波脉冲遇到被测介质表面被反射回来，部分反射回波被同一换能器接收，转换成电信号。 At this time, in 1993, American physicists discovered the working principle of the ultrasonic level meter: The working principle of the ultrasonic level meter is that the transducer (probe) sends out high-frequency ultrasonic pulses, which are reflected back on the surface of the measured medium, and partially reflected back. The wave is received by the same transducer and converted into an electrical signal. Ultrasonic pulses propagate at the speed of sound waves. The time interval from transmitting to receiving ultrasonic pulses is proportional to the distance from the transducer to the surface of the measured medium. The relationship between this distance value S and the speed of sound C and the transmission time T can be expressed by the formula: S = CxT / 2. Because the transmitted ultrasonic pulse has a certain width, the reflected wave and the transmitted wave in a small area close to the transducer overlap and cannot be identified, and the distance value cannot be measured. This area is called the measurement dead zone. The size of the dead zone depends on the model of the ultrasonic level gauge.
的概念是与普通声波比较而言的，普通声波的频率是20HZ～20KHZ，而超声波的频率大于20KHZ，其每秒的振动次数(频率)甚高，超声波和普通声波在本质上是一至的，它们的共同点是都是一种机械振动，通常以纵波的方式在介质内传播，是一种能量的传播形式，其不同点是超声波频率高，波长短，在相同介质内传播的距离比普照通声波长，超声波液位计正是利用这一原理制成的，探头向被测物表面发射超声波脉冲信号，经过传导介质到达被测物表面，液位计接收从被测物表面反射回来的回波，测量出超声波脉冲从发送到接收反射回波的时间差，经内部逻辑运算，将这个时间差转换成距离，并以4～20mA的电流信号输出。 The concept of an ultrasonic level gauge is compared with ordinary sound waves. The frequency of ordinary sound waves is 20HZ ～ 20KHZ, and the frequency of ultrasonic waves is greater than 20KHZ. The number of vibrations per second (frequency) is very high. Ultrasound and ordinary sound waves are essentially It is one-to-one. Their common point is that they are all a kind of mechanical vibration. They usually propagate in the medium by longitudinal waves. They are a form of energy transmission. The difference is that the ultrasonic wave has a high frequency and a short wavelength and propagates in the same medium. The ultrasonic wave level gauge is made using this principle. The probe emits an ultrasonic pulse signal to the surface of the measured object and passes through the conductive medium to the surface of the measured object. The level gauge receives the measured object from the measured object. The echo reflected back from the surface measures the time difference between the ultrasonic pulse being transmitted and receiving the reflected echo. After internal logic operation, this time difference is converted into a distance and output as a current signal of 4-20 mA.