Ultrasonic wave is a kind of mechanical wave, which is a kind of propagation process of mechanical vibration in elastic medium. It is characterized by high frequency, short wavelength, small diffraction phenomenon, good directionality, and can be directional and propagated as rays. Ultrasonic waves have little attenuation in liquids and solids, so they have strong penetrating power. Especially in solids that are opaque to light, ultrasonic waves can penetrate for several tens of meters. When they encounter impurities or interfaces, they will have significant reflection. Ultrasonic liquid The bit meter works by using this principle.
In the ultrasonic testing technology, regardless of the ultrasonic instrument, the electrical energy conversion ultrasonic wave must be emitted, and then received and converted into an electrical signal. The device that performs this function is called an ultrasonic transducer, and is also called a probe. The ultrasonic transducer is placed above the liquid or level to be measured, and the ultrasonic wave is emitted downward. The ultrasonic wave passes through the air medium and is reflected back when it encounters the water surface or the object interface, and is then received by the transducer and converted into an electrical signal. After detecting this signal, the electronic detection part turns it into a level signal and outputs a standard signal for use by other instruments or control devices. The principle of propagation of ultrasonic waves in the medium can be known, if the medium pressure, temperature, density, humidity When the conditions are constant, the propagation speed of the ultrasonic wave in the medium is a constant. Therefore, when it is measured that the time required for the ultrasonic wave to be received from the arrival of the object surface or the liquid level reflection is received, the path through which the ultrasonic wave passes can be converted, thereby indirectly measuring the level or level data. The working principle of the ultrasonic level gauge is that the high-frequency ultrasonic pulse emitted by the transducer (probe) is reflected back on the surface of the measured medium, and the partially reflected echo is received by the same transducer and converted into an electrical signal. The ultrasonic pulse propagates at the acoustic velocity, and the time interval from the transmission to the reception of the ultrasonic pulse is proportional to the distance of the transducer from the surface of the measured medium. The relationship between the distance value S and the speed of sound C and the transmission time T can be expressed by:
S=CxT/2.
Since the transmitted ultrasonic pulse has a certain width, the reflected wave and the transmitted wave in a small region closer to the transducer overlap, and cannot be recognized, and the distance value cannot be measured. This area is called the measurement dead zone. The size of the blind spot is related to the model of the ultrasonic level gauge.
Ultrasonic level gauge installation requirements:
When the transducer emits an ultrasonic pulse, it has a certain emission opening angle. From the lower edge of the transducer to the surface of the medium to be measured, there shall be no obstacles in the area radiated by the transmitted ultrasonic beam. Therefore, the measures in the tank should be avoided as much as possible during installation, such as: ladder, limit Switches, heating equipment, brackets, etc. Also note that the ultrasonic beam must not intersect the feed stream.
When installing the instrument, please pay attention: the highest material level must not enter the measurement blind zone; the instrument must be kept at a certain distance from the tank wall; the instrument should be installed as far as possible so that the transducer's emission direction is perpendicular to the liquid surface.
Concerned about surprises
Label: Ultrasonic pulse Ultrasonic level gauge Transducer Installation requirements CxT
Previous: Using RADIOSS software to strengthen the roof of a certain model Next: Analysis of fatigue strength of the telescopic frame of subway car
Water Pipe,Connection Parts,Machine Part
Chuang Hong Mei Metal Products Co., Ltd. , http://www.tzcastingmfg.com