The speed of the ultrasonic beam(ultrasonic pulse) in the fluid is affected by the direction of flow and the flow rate, or the movement of particles in the fluid affects the frequency or phase of the ultrasonic beam. These phenomena can be used to measure the flow rate(flow rate) of the fluid, resulting in an ultrasonic flowmeter.
The world's first ultrasonic flowmeter was born in Germany in 1928 and has developed rapidly since then. Up to now, nearly ten domestic companies have manufactured or represented this product, from the original only liquid ultrasonic flowmeter to the present gas ultrasonic flowmeter. With the rapid development of electronic technology, the performance and application of this product have been greatly improved. Its main advantages are:
1. No interference flow field, no pressure loss, no moving vulnerable parts, the same as electromagnetic flowmeter.
2. It can measure conductive and non-conductive fluids. It can be used for multiple uses on multiple pipelines(clamping types) and can be used as an auxiliary instrument for field verification.
3, the ultrasonic flowmeter sensor(transducer) can be inserted into the wall of the tube to make it "online", which can achieve higher measurement accuracy(liquid, four-channel, accuracy 4-0 .5 %), and can also put the transducer into the measuring tube. The outer wall, Non-contact measurement, high pressure fluid, toxic fluid, corrosion fluid flow measurement problems.
However, it also has some disadvantages. For example, the output signal of the converter is vulnerable to electromagnetic interference, zero instability, and relatively troublesome operation. The installation of new worktables usually requires professionals to debug on site, which requires higher sensor installation requirements, and attention should be paid to cleaning the adhesives on them during use.
Considering the price of the product and the technical requirements for installation and commissioning, it is recommended that the product be used for large and medium-sized diameter flow detection points. The process pipeline to be measured should be regular, the wall thickness is uniform, there are no rust spots, precipitation and liquid accumulation, etc.(as far as possible in the form of a "pipe segment").