Is Master The Skills Of Ultrasonic Transducers And Be Successful.
According to the principle of piezoelectric ultrasonic transducer for flowmeter ,it can be divided into ultrasonic piezoelectric , ultrasonic electromagnetic and ultrasonic laser . ultrasonic piezoelectric ultrasonic waves are excited by the piezoelectric crystal as a transducer. When piezoelectric ultrasound using the non-destructive testing, they need to use probe and the measuring object between the use of water, oil and other media as a coupling agent ,thus limiting its application. Although automatic testing equipment of piezoelectric ultrasonic has the defects of slow detection speed, complicated operation and need coupling agent, in the ultrasonic non-destructive testing of pipelines, because the crude oil in the pipeline can be used as the coupling medium, the piezoelectric ultrasonic transducer for milk is still widely used, and the technology is mature. ultrasonic Electromagnetic is the use of electromagnetic induction principle to stimulate ultrasound. It uses a periodic current in the metal under test produces a periodically changing induced current, the induced current under the action of an applied magnetic field, resulting in a periodically changing Lorentz force, acting on the metal crystallization point Array, make the crystal transducer produce periodic vibration, thus stimulating the ultrasonic transducer sensor datasheet .The application of electromagnetic ultrasonic non-destructive testing, no coupling medium, you can on the high temperature, high speed, surface roughness, the surface of the scale and paint objects directly detected. The disadvantage is that only the detection of metal materials, detecting sensitivity is low, susceptible to electromagnetic interference. As for the oil pipeline, since the pipe wall is made of metal material, and the wall of the pipe has a wax layer, it is particularly suitable for electromagnetic ultrasonic testing, but electromagnetic interference and low detection sensitivity must be solved. There are already electromagnetic ultrasonic testing device put into use. Laser ultrasound flow meter transducer for water tube will be a bunch of high-energy laser pulse incident on the surface of the measured object, due to its instantaneous thermal effects, so that the incident point to absorb heat and expansion, thus stimulating the ultrasound. Regardless of whether the incident laser beam is perpendicular to the surface of the object to be measured, the generated ultrasonic waves are perpendicular to the surface of the object to be measured. Therefore, an object with a rough surface, a large curvature and a complex geometric shape is also suitable. In addition, the entire measurement process will not be electromagnetic noise interference. Due to the narrow pulse width of the laser ultrasonic wave, its ability to detect small defects is stronger than other methods. The disadvantage is that the sensitivity of the receiving device is low.