Intelligent electromagnetic flowmeter measurement accuracy is high, stable performance, is the most common products in the flowmeter, widely used in petroleum, chemical, food and other industries, especially water resources system, almost everywhere can see the figure of intelligent electromagnetic flowmeter, but in these cases the measured medium is a single liquid.
1. Liquid containing bubbles
The liquid mixed with tiny bubbles can be measured normally, but when the gas content of the mixture volume flow containing the volume of bubbles is increased to form a block flow, the electrode is covered by gas, the circuit may be cut off instantly, and the output will shake, and it cannot function normally.
2. Solid-liquid two-phase flow of liquid
The volume flow of the two phases can also be measured for the solid-liquid two-phase fluid containing non-ferromagnetic particles or fibers. Fluids with high solid content, such as drilling mud, drilling cement mud, pulp, etc. Because the solid flows together in the carrier liquid, there is a slip between the two, the speed is different, single-phase liquid inspection instrument used for solid-liquid two-phase flow will produce additional errors.
In the case of the large particle friction electrode surface in the slurry, the peak slurry noise occurs in the electromagnetic flowmeter with low frequency rectangular excitation, and the flow signal becomes unstable, the high-frequency instrument and the instrument with strong ability to suppress the slurry noise are selected.
3. Liquids containing ferromagnetic substances
The fluid containing strong magnetic substances for the usual electromagnetic flowmeter, the permeability of the measurement tube changes according to the content of the strong magnetic body, resulting in the measurement error, but by placing the magnetic flux detection line in the magnetic circuit of the electromagnetic flowmeter emf compensation, can reduce the influence of the strong magnetic body mixed. The test report shows that the water contains liquid solid weight ratio of about 4:1, granularity ≤0.15mm iron fine ore pulp, 80mm diameter instrument for water and slurry comparison flow test, the usual instrument indicates the value change of 7%-10%, equipped with magnetic flux detection coil instrument, indicating the value error within ±2%Fs.
4. Pulp
The pulp used to measure the ore particles should pay attention to the wear degree of the sensor lining, and the increase of the inner diameter of the measuring tube will cause additional errors. In this case, it is proposed to install the sensor on the vertical pipe while selecting the ceramic liner or polyurethane rubber liner with good wear resistance, so that the wear of the pipe is uniform and the local wear of the lower part of the horizontal installation is eliminated.
