The main components of the split type electromagnetic flowmeter sensor are: measuring tube, electrode, excitation coil, iron core, and magnetic yoke housing. If the sensor and converter are installed separately and independently, it is called a split type electromagnetic flowmeter. Remember that cable connections are also an important component of electromagnetic flow meters.

The measurement principle of split type electromagnetic flowmeter is based on Faraday’s law of electromagnetic induction. The split type electromagnetic flowmeter consists of a sensor and a converter. The sensor is installed on the measurement pipeline, and the converter is installed within 30 meters or 100 meters from the sensor. The two are connected by a shielded cable.

To prevent external noise from entering, signal cables usually use dual core shielded wires. When measuring liquids with low conductivity and gathering for more than 30m, in order to prevent signal attenuation caused by partial capacitance of the cable, it is also required to connect a shielding driver with the same potential and low impedance source as the core wire to the inner shielding. The converter of the split type electromagnetic flowmeter can be kept away from harsh on-site environments, making electronic component inspection, adjustment, and parameter setting more convenient.

Working principle of split electromagnetic flowmeter measurement

According to Faraday’s principle of electromagnetic induction, a pair of detection electrodes are installed on the tube wall perpendicular to the axis of the measuring tube and the magnetic field lines. When the conductive liquid moves along the axis of the measuring tube, it cuts the magnetic field lines and generates an induced potential. This induced potential is detected by the two detection electrodes, and the value is proportional to the flow rate. Its value is:
E=KBVD

In the formula:
E – Induced potential;
K – coefficient related to magnetic field distribution and axial length;
B – Magnetic induction intensity;
V – average flow velocity of conductive liquid;
D – electrode spacing; (Measuring the inner diameter of the tube)

The sensor uses the induced potential E as a flow signal, which is transmitted to the converter. After amplification, transformation, filtering, and a series of digital processing, the instantaneous and cumulative flow rates are displayed on a backlit dot matrix LCD. The converter has 4-20mA output, alarm output and frequency output, and is equipped with communication interfaces such as RS-485, and supports HART and MODBUS protocols.

Characteristics of split type electromagnetic flowmeter:

1. There are no movable parts inside the measuring tube, which facilitates maintenance and management; No obstruction components, therefore no pressure loss.
2. The conductivity of the tested liquid is ≥ 5 μ s/cm, and when combined with various lining materials, it can be used to measure the flow rate of various acid, alkali, salt solutions, as well as mud, slurry, pulp and other media.
3. The measurement of flow is not affected by changes in fluid density, viscosity, temperature, pressure, and conductivity. The sensor’s induced voltage signal is linearly related to the average flow rate, resulting in high measurement accuracy.
4. Reasonable selection of lining and electrode materials can achieve good corrosion resistance and wear resistance.
5. Low frequency rectangular wave excitation, not affected by power frequency and various stray interferences on site, stable and reliable operation.
6. It is not affected by the direction of the fluid and can be accurately measured in both directions.
7. The range ratio is 1:120 (0.1m/s~12m/s), and the full range flow velocity range is wide.
8. Chinese character LCD backlight display, parameters can be modified online, and the operation is simple and convenient.
9. It has air traffic control measurement and alarm functions, and can adapt to different fluid media.
10. Power off time recording function, automatically records the interruption time of the instrument system power supply, and compensates for missed flow.
11. Hourly total recording function, which records the total flow in hours and is suitable for time-sharing measurement system

Technical parameters

Ambient temperature	-10—+50℃
accuracy level	Pipe type: 0.5 grade, 1.0 grade
Temperature of the measured medium	Ordinary rubber lining: -20 – +60℃; High temperature rubber lining: -20 – +180℃ Polytetrafluoroethylene lining: -30 – +120℃; F46 lining: -30 – +200℃
Rated working pressure	DN10—DN65：2.5MPa DN80—DN150：1.6MPa. DN200—DN1200：1.0MPa DN700—DN3000：0.6MPa.
Output signal and load resistance	4-20mADC,0-500Ω
Electrode material	Molybdenum containing stainless steel, titanium (Ti), tantalum (Ta) Hastelloy (HB) and so on
Class of protection	Submersible type: IP68, other: IP65
Power supply	220VAC、24VDC、3.6V Lithium battery
Length of straight pipe section	Pipeline type: upstream ≥5DN, downstream ≥2DN
Connection mode	The electromagnetic flowmeter is installed in the pipe type, and flange connections are adopted between it and the piping

The split type electromagnetic flowmeter has the advantage of stability, which can output standard current signals (4-20mA) for recording, adjustment, and control while meeting on-site monitoring and display requirements; Can be applied to liquid flow measurement of conductive materials in process pipelines of industries such as chemical, environmental protection, textile, metallurgy, mining, medicine, papermaking, water supply, food, sugar, brewing, etc; In addition to measuring general conductive liquids, it can also measure the flow rate of conductive liquid-solid two-phase flow, high viscosity liquids, salts, strong acids, strong bases and other liquids according to the special needs of users. Applied in chemical fiber, food, papermaking, sugar manufacturing, mining and metallurgy, water supply and drainage.

1. Suitable for liquid flow detection with conductivity greater than 5 μ s/cm. Changes in conductivity do not affect performance changes
2. Electromagnetic flow meters have long-term high measurement accuracy and are actually not affected by fluid physical properties
3. Easy to put into operation, the flowmeter is automatically set within the range of 0-10m/s, without the need to change the measurement range
4. The components in contact with the tested medium have good corrosion resistance and wear resistance, and are widely applicable
5. There are no movable parts or flow blocking components inside the pipeline
6. The measurement results are independent of physical parameters such as flow velocity distribution, fluid pressure, temperature, density, viscosity, etc
7. On site, the range can be modified online according to the actual needs of the user
8. High definition backlit LCD display, Chinese menu operation, easy to use, simple to operate, easy to learn and understand
9. All digital processing, strong anti-interference ability, reliable measurement, high accuracy, flow measurement range up to 150: one
10. There are three integrators inside that can display the forward cumulative and reverse cumulative amounts, as well as the difference cumulative amount. There is also a non power down clock inside that can record the power down time
11. There are communication signal outputs such as 4-20mA, RS485, RS232, Hart, and Modbus
12. It has self checking and self judging functions
13. The electromagnetic flowmeter is easy to use. After installation, simply connect the power supply without any other operation. Connect the signal line to output standard signals, which is convenient for non professionals to use. No mechanical moving parts, regular maintenance