Electromagnetic flow meters have high measurement accuracy and stable performance, and are widely used in the sewage treatment and wastewater discharge treatment industry. Intelligent electromagnetic flow meters can be seen in the petroleum and chemical industries. Electromagnetic flowmeter is used to measure conductive liquids, so what will be the result of measuring mixed liquid electromagnetic flowmeter?
Liquid containing bubbles
The medium mixed with tiny bubbles can be measured normally, but when the volume of the bubbles is too large, the electrode may be covered by gas, and the circuit will be instantly cut off, causing the output to shake and unable to function properly.
Liquid in solid-liquid two-phase flow
Solid liquid two-phase fluids containing non-magnetic particles or fibers can also measure the volumetric flow rate of the two phases. Fluids with high solid content, such as drilling mud, drilling cementing cement slurry, pulp, etc. Due to the solid flowing together in the carrier liquid, there is sliding between the two, resulting in a difference in speed. Instruments used for single-phase liquid testing for solid-liquid two-phase flow will produce additional errors.
When large particles in the slurry rub against the surface of the electrode and peak shaped slurry noise occurs in a low-frequency rectangular excitation electromagnetic flowmeter, and the flow signal becomes unstable, high-frequency instruments and instruments with strong ability to suppress slurry noise should be selected.
Liquid containing ferromagnetic substances
Fluid containing strong magnetic substances can cause measurement errors in conventional electromagnetic flow meters, as the permeability inside the tube varies according to the content of the strong magnetic material. However, by placing a magnetic flux detection line on the outer side of the electromagnetic flow meter emf for compensation in the magnetic circuit, the influence of the mixing of strong magnetic materials can be reduced. The test report shows that the water contains iron ore slurry with a liquid-solid weight ratio of about 4:1 and a particle size of ≤ 0.15mm. When comparing the flow rate of clean water and slurry using an 80mm caliber instrument, the typical instrument reading changes by 7% -10%. The instrument equipped with a magnetic flux detection coil has an indication error within ± 2% Fs.
slurry
When measuring slurry containing ore particles, attention should be paid to the degree of wear on the sensor lining, as expanding the inner diameter of the measuring tube may result in additional errors. In this case, it is proposed to install sensors on vertical pipes while selecting ceramic or polyurethane rubber liners with good wear resistance, so that the wear of the pipes is uniform and the disadvantage of severe local wear in the lower half of horizontal installation is eliminated.
The above brief introduction shows that intelligent electromagnetic flow meters can be used to measure mixtures, avoid related problems, and also achieve good measurement results.