Ultrasonic circulation measurement is predicated on the precept of transmission and receipt of sound waves, which have a singular high quality of bouncing off most objects – strong, liquid or gaseous. This know-how is vastly totally different from conventional circulation measurement applied sciences that use generators or thermal sensors to measure the circulation fee of fluids.Demand from business for increased accuracy and decrease prices have led to improvement of ultrasonic circulation measurement applied sciences that fulfill meet the necessities of wide selection of purposes and processes. Whereas there are variety of totally different applied sciences in ultrasonic measurement presently out there out there, these can broadly be categorized into 4 varieties. This categorization is predicated on the precept on which these applied sciences are primarily based.
Transit-time TechnologyThis the unique ultrasonic know-how developed for measurement of circulation fee of fluids. The know-how makes use of the transit time of sound waves to measure velocity. An ultrasonic circulation meter primarily based on this know-how has two ultrasonic transducers. These transducers act as each transmitters and receivers of ultrasonic sound waves. To measure the circulation fee or velocity of fluid – both gasoline or liquid by way of the pipe, the circulation meter alternates between sending and receiving bursts of ultrasonic sound waves by way of the transducers. The time taken by the sound waves to journey from the transmitting transducer to the receiving one provides a precise studying of the speed of liquid within the pipe.
Ultrasonic Doppler TechnologyThis know-how additionally works through the use of two ultrasonic sound transducers. Nevertheless, in contrast to the transit-time know-how, Doppler makes use of one transducer as a steady transmitter of ultrasonic sound waves. The opposite transducer acts as a steady receiver. Sound waves launched into the circulation are mirrored or scattered again off suspended particles or bubbles within the fluid and captured by the receiving transducer.The reflection causes a frequency shift within the sound waves, which is named the Doppler Impact. By measuring this frequency shift it’s attainable to find out the circulation velocity of the fluid within the pipe. This velocity, when computed with the cross-section space of the pipe provides the circulation fee of pipe circulation.
Cross-correlation Measurement TechnologyCross-correlation measurement know-how works on the precept that turbulent circulation of a fluid is shaped of eddies which have almost constant traits throughout a small cross-section of circulation. This is named the correlation size. A circulation meter primarily based on cross-correlation measurement know-how has two ultrasonic sensors positioned alongside the path of circulation of fluid.The primary or upstream sensor picks up the signature of turbulence L/V seconds earlier than the second or downstream sensor, the place L is the gap between the 2 sensors and V is the speed of circulation of fluid. The rate thus seems to be L/T, the place T is the time delay in detection between the 2 sensors.
Acoustic Doppler Velocity Profiling TechnologyThe acoustic Doppler Velocity Profiling know-how works on the identical precept because the Doppler know-how, with the distinction that it makes use of three transducers as a substitute of two. One of many transducers is a narrow-beam transducer whereas the opposite two are massive angle ones. The three transducers are organized in a straight line with the slender angle one positioned immediately above the circulation whereas the opposite two ones are positioned on both aspect of it.The center transducer emits ultrasonic sound waves at a hard and fast Pulse Repetition Frequency (PRF), which get scattered from particles inside the fluid. The opposite two transducers obtain these mirrored waves and supply a “pulse-to-pulse” algorithm. This in flip permits the measurement of the Doppler shift in two totally different instructions, which can be utilized to create a 2D velocity profile.