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Intelligent electromagnetic flowmeter

The intelligent electromagnetic flowmeter is a kin
  • Tel:0550-7989666、0550-7989999
  • Fax:0550-7989666
  • Mail:tkjd@tiankang.com

1. Product Overview

The intelligent electromagnetic flowmeter is a kind of induction instrument that measures the volume of the conductive medium in the tube according to Faraday's law of electromagnetic induction. The digital excitation is realized by using the embedded technology of single chip microcomputer. The electromagnetic flowmeter can also display the 4-20mA current signal for recording, adjusting and controlling. It has been widely used in chemical technology, environmental protection, metallurgy, medicine, paper making, water supply and drainage, and other industrial technology and management departments.

The electromagnetic flowmeter can not only measure the flow rate of the general conductive liquid, but also measure the volume flow rate of the solid liquid two phase flow, the high viscosity liquid flow and the salt, strong acid and strong alkali liquid.

Two, working principle

The principle of intelligent electromagnetic flowmeter is based on Faraday's law of electromagnetic induction. The measuring tube of the flowmeter is a non magnetic alloy short tube lined with insulating material. Two electrodes pass through the tube wall along the pipe diameter and are fixed on the measuring tube.The electrode head is basically flush with the inner surface of the lining. When the excitation coil is excited by two way square wave excitation, a magnetic field with a magnetic flux density of B will be generated in the direction perpendicular to the axis of the measuring tube. At this point, if a fluid with a certain conductivity flows through the measuring tube, the cutting force line will be induced to emit the electromotive force E. The electromotive force E is directly proportional to the magnetic flux density B, the product of the inner diameter D of the measuring tube and the average velocity V. The EMF E (flow signal) is detected by the electrode and sent to the converter through the cable. After amplifying the flow signal, the converter can display fluid flow and output pulses, simulate current and other signals for controlling and adjusting the flow.



Formula: E--- is the signal voltage between electrodes (V).

B--- magnetic flux density (T)

D--- measuring tube inner diameter (m)

V--- mean velocity (M / s)

Type K and D are constants. Because the excitation current is constant current, B is also constant, and E=KBdV is known. The volume flow Q is proportional to the signal voltage E, that is, the signal voltage E of flow induction is linearly related to the volume flow Q. Therefore, as long as the E is measured, the flow rate Q can be determined. This is the basic principle of electromagnetic flowmeter.

From E=KBdV, we can know that the temperature, pressure, conductivity, liquid solid ratio of liquid solid two phase fluid and other parameters will not affect the measurement results. As for the flow state, as long as it meets the axisymmetric flow (such as laminar or turbulent flow), it will not affect the measurement results.Therefore, electromagnetic flowmeter is a true volume flowmeter. For manufacturers and users, as long as the actual calibration of ordinary water can be used to measure the volume flow of any other conductive fluid medium without any modification, it is a prominent advantage of electromagnetic flowmeter, and is not available by any other flowmeter. There is almost no pressure loss and high reliability in measuring the inactive and choke components in the tube.

Three, performance characteristics

1. instrument structure is simple, reliable, no movable parts, long working life.

2. no choke block, no pressure loss and fluid blockage.

3. without mechanical inertia, fast response and good stability, it can be applied to automatic detection and adjustment of program control system.

4. the measurement accuracy is not affected by the type of medium and its physical parameters such as temperature, viscosity and pressure.

5. different combinations of PTFE or rubber lining and HC, HB, 316L, Ti and other electrode materials can meet the needs of different media.

6. full digital processing, strong anti-interference ability, reliable measurement and high precision, and the flow measurement can reach 150:l.

7. full Chinese character menu operation, easy to use and easy to operate.

8. high definition backlight LCD display.

9. has two-way flow measurement, two-way cumulative function, and three internal integrators can display positive cumulative value, reverse cumulative value and difference cumulative amount respectively.

10. output mode: current, frequency bidirectional output function and RS-485, MODBUS, HART interface.

11. adopting SMD device and surface mount (SMT) technology, the circuit has high reliability.

Four, technical parameters

1. complete machine and sensor technical data

Executive standard

JB / T9248 l999

Nominal diameter

10, 15, 20, 25, 32, 40, 50, 65, 80, 100, 125, 125, 125, 125, 125, 125, l000, L200, L800, P, C, C, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P, P

Current Speed

15m / S


Level 0.5, level 1 (with caliber).

Fluid conductivity

More than 5uS / cm

ambient temperature

Sensor: (-40 ~ +80) C, converter: (-l5 ~ +50) C

Lining material

Polytetrafluoroethylene, polychloroprene rubber, polyurethane, polyfluoroethylene propylene (F46)

Fluid temperature

Less than 120 degrees centigrade

Electrode materials

316L, Hastelloy C, Hastelloy B, titanium, tantalum, platinum / iridium alloy, stainless steel coated tungsten carbide.

Flange material

Carbon steel and stainless steel

Enclosure protection


Explosion proof sign

Ex II BT6 Gb

2. converter technical data

Power Supply


(18~30) V


(85~265) V (45~63) Hz


< 20W (with sensors)

Internal integrator

Positive volume, reverse flow and difference amount have total integrator.

Output signal


Current output

Output signal: two-way two-way isolation, full isolation (0 ~ l0) mA / (4~20) mA

Load resistance: (0 ~ l0) mA, (0 ~ 1.5) K ohm; (4~20) mA, (0~750) Omega

Basic error: plus l0 A on the basis of the above measurement error.

Frequency output

Forward and reverse flow output, the upper limit of output frequency can be set in 1 ~ 5000Hz.

Transistor collector open circuit bidirectional output with photoelectric isolation

The external power supply is not more than 35V, and the collector current is 250mA when conducting.

Pulse output

Forward and reverse flow output, the upper limit of output frequency can reach 500cp / S

* automatic setting of pulse width or 20ms Fang Bo

Transistor collector open circuit bidirectional output with photoelectric isolation

When the external power supply is not larger than 35V., the collector current is 250mA

Flow direction output

It can measure the fluid flow in positive and negative directions and determine the direction of fluid flow.

Alarm output

Two transistor collector open circuit alarm outputs with photoelectric isolation.

The external power supply is not more than 35V, and the collector current is 250mA when conducting.

Alarm status: fluid ATM, excitation disconnection and flow overrun.

communication interface

RS-485, MODBUS and HART are protected against lightning stroke.

Damping time

In (1~64) s

Normal working conditions

Ambient temperature: (-10 ~ 60) C, relative humidity: 5% ~ 90%

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