What media flow measurement is the vortex flowmeter mainly used for?

Can vortex flowmeters measure liquids? Can vortex flowmeters measure gases? How is the performance of vortex flowmeters in measuring steam? The vortex flowmeter must ensure at least 15 times the pipe diameter in front of the flowmeter and 5 times the pipe diameter after the flowmeter. If there are interference sources such as elbows, indentations, expansions, etc. in front of the flowmeter, it is necessary to ensure 30-40 times the pipe diameter in front of the flowmeter and 6 times the pipe diameter after the flowmeter. The flowmeter should be installed upstream of the regulating valve, pressure or temperature sensor.

What media flow measurement is the vortex flowmeter mainly used for: such as gas, liquid, steam and other media. By setting a triangular prism-shaped vortex generator in the fluid, regular vortices are generated alternately from both sides of the vortex generator. This vortex is called a Karman vortex, and the vortex columns are arranged asymmetrically downstream of the vortex generator. Common problems mainly include long-term inaccurate indication; no indication at all; indication fluctuates over a large range and cannot be read; indication does not return to zero; no indication at low flow; indication is OK at high flow, but inaccurate at low flow; indication changes cannot keep up with flow changes; instrument K coefficient cannot be determined, and multiple data are inconsistent. Summarizing the main reasons for these problems, they mainly involve the following selection issues.

The improvement of vortex flowmeter technical indicators is the pursuit of industry development, such as the measurement range, resistance from superconducting to 1014Ω, and temperature from near absolute zero to 1010℃. For example, in terms of measurement accuracy, time measurement has increased from 1 second in 300,000 years to 1 second in 6 million years. Pursuit of high stability and high reliability With the continuous expansion of the application fields of instrumentation and measurement and control systems, reliability technology plays an important role in maintaining normal operation in large-scale projects and industrial production such as aerospace, electric power, metallurgy, and petrochemicals. The vortex flowmeter that ensures the normal operation of the measurement and control system of field instruments also requires high stability and high reliability. Due to the emergence of new materials and the development of various processing technologies, modern reliability has increased by 3 times compared with 10 years ago in terms of mean time between failures. The application occasions of miniature portable vortex flowmeters have gone out of the laboratory. Both on-site calibration and the actual needs of environmental protection require portable vortex flowmeters.

The thermal detection element of the vortex flowmeter has high sensitivity and is suitable for measuring gas scenes at lower temperatures (<200℃) and lower densities. However, because the thermistor is encapsulated with glass, it is relatively fragile and easily affected by dirt, harmful substances and particulate matter in the fluid, so the measured medium should also be a clean liquid or gas. Piezoelectric elements are resistant to dirt, so they are widely used, but they are not suitable for measuring low-density, low-flow gas and occasions with large environmental vibration. The medium temperature range is -32～110℃. At room temperature, piezoelectric ceramics are insulated and have an impedance of 10～100MΩ, but if they work at 300℃, the impedance will drop to 1MΩ, or even tens of kilo-ohms, and the output signal will become smaller, resulting in the deterioration of the low-frequency characteristics of the measurement system, so it cannot be used for high-temperature media. The ultrasonic vortex flowmeter has strong vibration resistance, but the medium temperature cannot be higher than 200℃. If it exceeds this range, the ultrasonic probe will be damaged. Ultrasonic vortex flowmeters also cannot be used in situations where the measured medium has obvious pulsation, such as the fluid at the outlet of a reciprocating compressor, because they are highly sensitive to small flows.