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What are the advantages and disadvantages of ultrasonic flowmeters?

Ultrasonic flowmeter is a new type of flow measuring instrument. It adopts advanced multi-pulse technology, signal digital processing technology and error correction technology to make the flow meter more adaptable to the industrial scene environment, and the measurement is more convenient, economical and accurate. Today we will introduce the advantages and disadvantages of ultrasonic flowmeters in detail, and hope to help everyone.
advantage
Ultrasonic flowmeters are non-contact meters that measure both medium flow in large diameters and media that are difficult to access and observe. Its measurement accuracy is very high, and it is hardly interfered by various parameters of the measured medium. In particular, it can solve the problem of flow measurement of strong corrosive, non-conductive, radioactive and flammable and explosive medium that other instruments cannot.
Disadvantage
The shortcomings of today are mainly that the temperature range of the measurable fluid is limited by the temperature resistance of the ultrasonically-transformed aluminum and the coupling material between the transducer and the pipe, and the original data of the sound velocity of the fluid to be measured at a high temperature is incomplete. At present, China can only be used to measure fluids below 200 °C. In addition, the measurement line of the ultrasonic flow meter is more complicated than the general flow meter. This is because the flow rate of liquid in general industrial metering is often several meters per second, and the propagation speed of sound waves in liquid is about 1500 m/s. The change of flow velocity (flow rate) of measured fluid brings about the change of sound velocity. ** is also 10-3 orders of magnitude. If the accuracy of measuring the flow rate is required to be 1%, the accuracy of measuring the speed of sound needs to be on the order of 10-5 to 10-6, so it is necessary to have a perfect measuring circuit to achieve this. Ultrasonic flowmeters can only be used in practical applications under the premise of rapid development of integrated circuit technology.
Ultrasonic flowmeter consists of three parts: ultrasonic transducer, electronic circuit and flow display and accumulation system. The ultrasonic transmitting transducer converts electrical energy into ultrasonic energy and emits it into the fluid to be measured. The ultrasonic signal received by the receiver is amplified by the electronic circuit and converted into an electrical signal representing the flow to be supplied to the display and the integrated meter for display. And the total calculation. This enables the detection and display of traffic.
Ultrasonic flowmeters are commonly used in piezoelectric transducers. It utilizes the piezoelectric effect of the piezoelectric material and applies an appropriate transmitting circuit to the piezoelectric element of the transmitting transducer to generate ultrasonic vibration. Ultrasonic waves are incident into the fluid at an angle and then received by the receiving transducer and converted to electrical energy by the piezoelectric element for detection. The transmitting transducer utilizes the inverse piezoelectric effect of the piezoelectric element, while the receiving transducer utilizes the piezoelectric effect.
The piezoelectric element of the ultrasonic flowmeter transducer is often made into a circular sheet that vibrates along the thickness. The diameter of the sheet exceeds 10 times the thickness to ensure the directionality of the vibration. The piezoelectric element material is mostly lead zirconate titanate. In order to fix the piezoelectric element, the ultrasonic wave is injected into the fluid at a suitable angle, and the component is required to be in the human voice wedge to form the entire transducer (also called the probe). The material of the acoustic wedge not only requires high strength and aging resistance, but also requires that the ultrasonic energy after the wedge is small, that is, the transmission coefficient is close to 1. The commonly used acoustic wedge material is plexiglass, because it is transparent, and the assembly of piezoelectric elements in the wedge can be observed. In addition, some rubber, plastic and bakelite can also be used as the acoustic wedge material.

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