Electromagnetic flowmeter because of its own product advantages, the use is very wide, the measured media is relatively more diversified, today electromagnetic flowmeter manufacturers Qingtian meter table for the measurement of special media, to help customers do explain, we remember to collect.
- Electromagnetic flowmeter measures liquid containing ferromagnetic substances
For the fluid containing ferromagnetic material, the measurement error will be caused because the permeability in the measuring tube is changed by the different content of ferromagnet in the ordinary electromagnetic flowmeter.
But the electromagnetic flowmeter EMF with flux detection coil compensation is installed in the magnetic circuit.
The effect of the mixed ferromagnet can be reduced.
The test report shows that the slurry containing iron concentrate ore in water with a liquid-solid weight ratio of about 4:1 and particle size ≤0.15mm is compared with the slurry flow rate test using an 80mm diameter meter. The normal meter shows a change of 7% to 10%. The meter equipped with magnetic flux detection coil shows an error of ±2%Fs.
- Electromagnetic flowmeter measures the liquid of solid-liquid two-phase flow
The volumetric flow of solid – liquid dual – phase fluid containing non – ferromagnetic particles or fibers can also be measured.
Fluids with higher solid content, such as drilling mud, drilling cement slurry, pulp, etc., are actually non-Newtonian fluids.
Because the solids flow together in the carrier liquid, there is a slip between the two and a difference in speed, the single-phase liquid check instrument used for solid-liquid two-phase flow will generate additional error.
It is reported abroad that the error is within 3% when the solid content is 14%.
According to the experimental report of the Institute of Water Resources of The Yellow River Conservancy Commission of China, measuring the flow rate of water with high sediment content, the volume of sediment content is 17%-41% (median sand particle size is 0.35mm), and the meter measurement error is less than 3%.
In the grout there are large particles brush electrode surface, in the low frequency rectangular magnetic electromagnetic flowmeter will produce sharp grout noise, so that the flow signal is not stable, to choose a higher frequency of the instrument or have a strong ability to suppress grout noise, also can choose the utility ac magnetic instrument or dual frequency magnetic instrument.
- The electromagnetic flowmeter measures the liquid containing bubbles
The tiny bubbles mixed into bubble flow can still work normally, but the measured volume flow is the mixed volume flow with bubble volume.
If the gas content increases to form a bomb (block) flow, the electrode may be covered by the gas and the circuit will be disconnected instantaneously, resulting in output shaking and even failure to work normally.
4, electromagnetic flowmeter measurement pulp
In the application of slurry containing ore particles, attention should be paid to the degree of wear on the sensor lining, and additional errors will be generated by the expansion of the inner diameter of the measuring pipe.
In this case, ceramic lining or polyurethane rubber lining with better wear resistance should be selected. Meanwhile, it is recommended that the sensor be installed on the vertical pipe to make the pipe wear even and eliminate the serious wear on the lower part of the horizontal installation.
The nozzle sheath can also be installed at the sensor inlet to extend the service life.