Electromagnetic flowmeter
  • Electromagnetic flowmeter

Electromagnetic flowmeter

The LDE series electromagnetic flowmeter is an induction type instrument that measures the volume flow rate of conductive media inside a tube based on Faraday's electromagnetic induction law.

1、 Product Overview:

The LDE series electromagnetic flowmeter is an induction type instrument that measures the volume flow rate of conductive media inside a tube based on Faraday's electromagnetic induction law. It adopts embedded microcontroller technology to achieve digital excitation, and CAN fieldbus is used on the electromagnetic flowmeter. While meeting on-site display requirements, it can also output 4-20mA current signals for recording, adjustment, and control purposes. In addition to measuring the flow rate of general conductive liquids, the meter can also measure the volume flow rate of liquid-solid two-phase flow, high viscosity liquid flow, and salt, strong acid, and strong alkali liquids.

Integrated electromagnetic excitation utilizes constant current low-frequency ternary rectangular waves or dual frequency rectangular waves, which not only has the advantages of rectangular wave magnetic fields but also overcomes the disadvantages of sine wave magnetic fields; It can also eliminate errors caused by fluctuations in power supply voltage, changes in power supply frequency, and changes in excitation coil impedance; And it has zero point stability and is not affected by fluid noise interference. Therefore, it has the characteristics of high stability and high reliability. An electromagnetic flowmeter consists of a sensor and a converter. The sensor is installed on the measurement pipeline, and the converter can be combined and connected with the sensor to form an integrated flowmeter.

The split electromagnetic flowmeter adopts a split design, which is convenient for maintenance and increases the service life of the electromagnetic flowmeter. Wall mounted flow converter effectively protects the sensor conversion circuit, which is beneficial for anti-corrosion, moisture-proof, and waterproof. The product has simple wiring and convenient installation. The split electromagnetic system 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 shielded cables to measure the volume flow rate of conductive liquids. The main components of the sensor are: measuring tube, electrode, excitation coil, iron core, and magnetic yoke housing. Mainly used to measure the volume flow rate of conductive liquids and slurries in closed pipelines.

2、 Working principle:

The LDE series electromagnetic flowmeter is based on the Faraday electromagnetic induction principle, and a pair of detection electrodes are installed on the tube wall perpendicular to the axis and magnetic field line of the measuring tube. When the conductive liquid moves along the axis of the measuring tube, it cuts the magnetic field line and generates an induced potential. This induced potential is detected by two detection electrodes, and the value is directly proportional to the flow rate. Its value is: E=KBVD. In the formula:

E - Induced electromotive force;

K - coefficient related to magnetic field distribution and axial length;

B - Magnetic induction intensity;

V - average flow rate of conductive liquid;

D - electrode spacing; (Measuring the inner diameter of the tube)

The sensor takes the induced electromotive force E as the flow signal and transmits it to the converter. After amplification, transformation filtering, and a series of digital processing, the instantaneous flow and cumulative flow 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. It also supports Hart and MODBUS protocols.

3、 Application scenarios:

The LDE series electromagnetic flowmeter is mainly used to measure the volume flow rate of conductive liquids and slurries in closed pipelines. Such as water, sewage, mud, pulp, various acid, alkali, salt solutions, food slurries, etc., are widely used in industries such as petroleum, chemical, metallurgical, textile, food, pharmaceutical, papermaking, as well as environmental protection, municipal management, water conservancy construction, and other fields.

4、 Structural form:

1. Sensors:

The sensor mainly consists of a measuring tube, measuring electrode, excitation coil, iron core, magnetic yoke, and housing.

a、 Measurement catheter: composed of stainless steel catheter, lining, and connecting flange, it is the carrier for measuring the on-site working conditions of the measured liquid.

b、 Measurement electrode: A pair of electrodes installed on the inner wall of the measurement catheter, perpendicular to the axial flow direction, to generate a signal for the measurement liquid.

c、 Excitation coils: The upper and lower excitation coils that generate a magnetic field inside the measuring conduit.

d、 Iron core and magnetic yoke: Introduce the magnetic field generated by the excitation coil into the liquid and form a magnetic circuit.

e、 Shell: Instrument outer packaging.

2. Converter:

It is an intelligent secondary meter, which amplifies and processes the flow signal through microcontroller operation, and can display flow rate, cumulative measurement, and output pulse, analog current and other signals for fluid flow measurement or control.

3. Product assembly form:

It is divided into two forms: one type and the other type.

a、 Integrated installation of sensors and converters.

b、 Split type: Sensors and converters are installed separately, forming a flow metering system through connecting cables.

c、 To meet the requirements of different media measurements, there are multiple options for the lining and electrode materials of sensors.

5、 Main features:

1. The instrument has a simple and reliable structure, no movable parts, and a long working life;

2. No interception and flow blocking components, no pressure loss or fluid blockage phenomenon;

3. No mechanical inertia, fast response, good stability, can be applied to automatic detection, adjustment, and programmable control systems;

4. The measurement accuracy is not affected by the type of medium being measured and its physical parameters such as temperature, viscosity, density, pressure, etc;

5. The use of PTFE or rubber material lining and different combinations of electrode materials such as Hc, Hb, 316L, Ti can adapt to the needs of different media;

6. There are various types of flow meters available, including pipeline and plug-in types;

7. Using EEPROM memory, the measurement and operation data storage protection is safe and reliable;

8. It has two types: integrated and separated;

9. High definition LCD backlight display.

6、 Technical parameters:

1. Instrument accuracy: pipeline type 0.5 level, 1.0 level; Plug in 2.5 level.

2. Measurement medium: Various liquids and liquid-solid two-phase fluids with a conductivity greater than 5 μ S/cm.

3. Flow rate range: 0.2-8m/s.

4. Working pressure: 1.6MPa.

5. Environmental temperature: -40 ℃~+50 ℃.

6. Medium temperature: PTFE lining ≤ 180 ℃; Rubber lining material ≤ 65 ℃.

7. Explosion proof sign: Exmibd Ⅱ BT4.

8. Explosion proof certificate number: GYB01349.

9. External magnetic interference: ≤ 400A/m.

10. Shell protection: Integrated type: IP65;

Separation type: sensor IP68 (underwater 5 meters, * * * limited to rubber lining); Converter IP65.

11. Output signal: 4-20mA DC, Load resistance 0-750 Ω.

12. Communication output: RS485 or CAN bus.

13. Electrical connection: M20 x 1.5 internal thread, with a diameter of 10 cable holes.

14. Power supply voltage: 90-220V AC, 24 ± 10% V.DC.

15. Power consumption: ≤ 10VA.