A good electromagnetic flowmeter has high measurement accuracy and stable product performance. At present, the accuracy of electromagnetic flowmeters is generally 0.3, 0.5, and some small-diameter products can achieve 0.2. Due to the particularity of its measurement principle, the measuring medium needs to have a certain conductivity (generally greater than 8US/cm), and at the same time, there are certain requirements for measuring the initial flow velocity (generally greater than 0.5m/s).
Electromagnetic flowmeters have many advantages in fluid flow, and are currently widely used in various industries.
1. There are no obstructing flow parts in the measuring tube, no pressure loss, and the requirements for straight pipe sections are relatively low;
2. High measurement accuracy, strong stability, and strong ability to engage in vibration interference;
3. The measurement is not affected by changes in liquid density, viscosity, temperature, pressure and conductivity;
4. It has a variety of electrodes and lining options, and has strong media abrasion ability;
5. The range ratio with the trap is generally 10:1 at a flow rate of 0.5~5m/s, and can be 100:1 or even 150:1 under some calibers and flow rates.
Of course, electromagnetic flowmeters also have their unique limitations;
1. The measuring medium must have a certain conductivity (generally greater than 5us/cm), and at the same time, there are certain requirements for measuring the initial flow velocity (generally greater than 0.5m/s)
2. The temperature of the measurement medium is limited by the lining material, and the measurement effect for high temperature medium is not good;
3. Unable to measure gas, vapor and other media;
4. When the measuring electrode works for a long time, scaling may occur, and it can only be measured after cleaning;
5. For the measurement of high viscous medium and solid-liquid medium, high frequency excitation method is required, and low frequency and low magnetic accuracy are poor;
6. Due to the limitation of the sensor structure principle, the cost of large-diameter products is too high, resulting in an increase in the diameter of the product and a linear increase in the price;
7. Due to the limitation of its principle, the instrument sensor coil needs to be energized to generate a magnetic field, and its power consumption is relatively high, which is not suitable for battery power supply.
Although there are some of the above shortcomings, the electromagnetic flowmeter is still widely used in the measurement of most liquid media, and its excellent measurement accuracy and low maintenance cost are deeply loved by customers.
