Ultrasonic Flowmeter the basic principles and types of ultrasound in the flow of transmission fluid when it contains information on the fluid flow. So to receive through the ultrasonic can be detected in the fluid flow, thus converted into traffic. According to the test, the speed difference can be divided into law, the Doppler method, beam offset, noise law and related laws, such as different types of ultrasonic flowmeter. Acoustic flowmeter from the past 10 years with the rapid development of integrated circuit technology before the start of a non-contact instruments, not suitable for measuring contact and observation of the large diameter and fluid flow. It can be linked with the water level gauge for measuring the flow of open water. The use of ultrasonic flow than not in the fluid measuring devices installed in it will not change the flow of fluid, and no additional resistance, installation and maintenance of the instrument can not affect the production pipeline operation and is thus an ideal energy-saving flow meter.

It is well known that the current industrial flow measurement widespread large diameter, large flow measurement difficult issues, this is because the general flow meter diameter measurement with the increase will bring the manufacturing and transport difficulties, the cost increase, the energy loss increases , Not only the installation of these shortcomings, ultrasonic flowmeter can be avoided. Because of various types of ultrasonic flowmeter can be installed outside, non-contact flow measurement, gauges and measured pipes cost basically nothing to do aperture size, and other types of flowmeters with the calibre to increase, a substantial increase in cost, the greater the calibre of ultrasonic flowmeter Other than the same function type flowmeter features more superior than the price. Is considered a better flow of large diameter measurement instruments, Doppler ultrasonic flowmeter can be measured two-phase media traffic, it can be used for sewerage and sewage water flow measurements, such as dirt. In power plants, using portable ultrasonic flowmeter into the water turbine, steam turbine cycle, such as large diameter water flow, than in the past from the skin to facilitate the flow of much more. Ultrasound can also be used for juice flow of gas measurement. Diameter of 2 cm from the scope of application to 5 m, from a few meters wide open, 500 m wide culvert to the river can be applied.

In addition, ultrasonic measuring instruments accurately measuring the flow of fluid almost from the measured temperature, pressure, viscosity, density and other parameters of the impact can be made of non-contact and portable measuring instruments, it addresses other types of instruments are difficult to measure The strong corrosive, non-conductive, radioactive and flammable and explosive medium flow measurement problems. In addition, in view of non-contact measurement characteristics, reasonable Coupled with the electronic circuits, a variety of instruments can adapt to a variety of diameter measurement and measurement of the flow. Ultrasonic Flowmeter the ability to adapt to other instruments is unparalleled. Ultrasonic Flowmeter with some of these advantages it has received increasing attention to the products and serialization, General Development, is now made of different channels of standard-based, high-temperature-and anti-explosive type, wet-type instrument to adapt to different media and different occasions And the different conditions of the pipeline flow measurement.

Ultrasonic Flowmeter the current existence of the major shortcomings can be measured by the fluid temperature range of ultrasonic transducer and aluminum transducer coupled with the pipeline between the temperature and extent of the restrictions, and the fluid under high temperature measured the speed of the original audio data Incomplete. China can only be used to measure 200 following the fluid. In addition, ultrasonic flowmeter measurement line than the general flow meter complex. This is because, in general industrial measurement of liquid flow is often several meters per second, while the liquid in the acoustic propagation velocity of about 1500 m / s around, measured fluid flow (traffic) brought changes in the velocity of change is also the largest 10 -- 3 orders of magnitude. If the flow rate measurement accuracy of 1%, while the speed of sound measurement accuracy required for the 10 -5 to 10 -6 order of magnitude, so there must be a sound measurement circuits can be achieved, and this is precisely ultrasonic flowmeter only in IC Before the rapid development of technology that could be the reason for their practical application.

Ultrasonic Flowmeter from ultrasonic transducer, electronic circuits and traffic display and the cumulative system consists of three parts. Ultrasonic transducer fired power will be converted to ultrasonic energy, and launched into the measured fluid in the receiver to receive the ultrasonic signals, the electronic circuits and converted to enlarge the representative of the traffic signals showed that the supply and Totalizer instrument display And Totalizer. This realization of the flow of detection and display.

Ultrasonic Flowmeter common piezoelectric transducer. It uses the piezoelectric effect of piezoelectric material, used to launch an electric circuit to launch transducer added to the piezoelectric components, to produce ultrasound-advised. To a certain point of view into the ultrasonic transmission fluid, and then by receiving transducer receiving, and the piezoelectric components into electrical energy, in order to detect. Launch transducer use of piezoelectric components of the inverse piezoelectric effect, while receiving transducer is the use of piezoelectric effect.

Ultrasonic Flowmeter the piezoelectric transducer components often caused circular sheet, along the thickness of vibration. Slice thickness of the diameter of more than 10 times to ensure that the vibration of direction. Use of piezoelectric material components PZT. To a fixed piezoelectric components, so that ultrasound into the right angle to the fluid, the components needed to wedge Lee Sheng, a transducer as a whole (also known as the probe). Sound wedge of material requires not only high strength, anti-aging, but also the sound of ultrasonic energy loss after small wedge that is, transmission coefficient close to 1. Acoustic materials commonly used wedge is plexiglass, as it transparent, sound wedge can be observed in the piezoelectric components in the assembly. In addition, certain rubber, plastic and bakelite can remain silent wedge material.

Ultrasonic Flowmeter the electronic circuit, including the launch, reception, signal processing and display circuit. Measured the instant flow of traffic and the cumulative value of using digital or analog display.

Based on the principles of signal detection, ultrasonic flowmeter generally can be spread by poor (including: direct jet lag, the time difference, phase, frequency difference) beam offset, Doppler law, the relevant law, space Filtering and noise and other types of law, as shown. One method to noise principle and structure of the most simple, easy to carry and measurement, are cheap but relatively low accuracy, suitable for the flow measurement accuracy Yaoqiubugao use of the occasion. As a direct jet lag, the time difference, frequency difference phase of law and the basic principles are by measuring the ultrasonic pulse-down and counter-current timekeeping to reflect the difference between the speed of the flow of fluid, it also collectively referred to as the transmission speed of poor law. One frequency difference of law and the time difference to overcome the speed of sound with the fluid temperature changes brought about by error, a higher degree of accuracy, that are widely used. Transducer in accordance with the allocation of different ways, speed Cibo is divided into: Z (by law), V (reflection), X (cross-law). Beam offset by the use of ultrasonic beam in the transmission fluid in the direction of fluid flow with the changes arising from migration to reflect the fluid flow rate, low-velocity, low sensitivity little applicability. Doppler method is the use of acoustic Doppler principle, by measuring the scattering of uneven fluid in the scattering of ultrasound to determine the Doppler frequency shift of fluid flow, applicable to the suspension of particles, such as bubble fluid flow measurement. Relevant law is to use technology related to measuring flow, principle, this method of measurement accuracy and the speed of sound in the fluid has nothing to do with the so fluid temperature, concentration, and other irrelevant and thus measurement accuracy, a wide range of application. However, the relevant price is expensive, more complex circuits. Wider application in the microprocessor, this shortcoming can be overcome. Noise (listening) is to use channels within the fluid flow when the noise and velocity of the fluid of the principle, expressed through the detection of noise or traffic flow value. The method is simple, cheap equipment, but the accuracy of the low.

Several methods have different features above, should be based on the measured fluid nature. Velocity distribution, installation of pipelines and the location of measurement accuracy of factors such as the requirement to choose. Generally speaking because of the quality of industrial production in the often can not maintain a constant temperature, the use of frequency difference in time of poor law. Only in diameter much of the time difference when direct. The transducer installation method of choice in general principle is: When the fluid flow along the axis parallel, optional Z; flow direction and when the uranium is not parallel or pipeline locations for the installation interval can be restricted, the use of V X law or law. When the flow field and the uneven distribution of the table before the straight and shorter, may also have multi-channel (such as two-channel or four-channel) to overcome the disturbance of the flow velocity measurement error. Doppler method suitable for measuring flow, conventional instruments can be avoided by the suspension of the tablets or bubble plug, wear, attachment and can not run the shortcomings, which are developing rapidly. With industrial development and the work of energy conservation, kerosene mixed (COM), a coal cement (CWM) and the delivery of fuel and fuel oil combustion-supporting water and other energy-saving methods of development, both for the Doppler ultrasonic flowmeter applications open up vast Prospects.