LDB Intelligent Type Electromagnetic Flow Meter

The LDB intelligent type electromagnetic flow meter consists of a sensor and a converter. It is based on Faraday's law of electromagnetic induction, which is used to measure the volume flow of conductive liquid with conductivity greater than 5μs/cm. It is an inductive meter for measuring the volume flow of conductive medium. In addition to measuring the volume flow of general conductive liquid, it can also be used to measure the volume flow of strong corrosive liquids such as strong acid and alkali and uniform liquid-solid two-phase suspension liquid such as slurry, pulp and paper pulp.


■ Full digital processing, strong anti-interference ability, reliable measurement, high precision, flow measurement range can reach 150:1;

■ Ultra-low EMI switching power supply, large voltage range of suitable power supply, good anti-EMI performance;

■Use 16-bit embedded microprocessor, with fast operation speed, high precision, and programmable low-frequency rectangular wave excitation,improving the stability of flow measurement and low power consumption;

■Use SMD parts and surface mount (SMT) technology, high circuit reliability;

■ No moving parts in the pipe, no flow blocking parts, and there is almost no additional pressure loss in the measurement;

■ It can modify the range online on site according to the actual needs of users;

■The measurement results are independent of the physical parameters such as flow velocity distribution, fluid pressure, temperature, density, viscosity;

■High-definition backlit LCD display, full Chinese menu operation, easy to use, easy to operate, easy to learn and understand;

■With digital communication signal output such as RS485, RS232, Hart and Modbus (optional);

■With self-test and self-diagnosis function;

■ With hourly total recording function, recording the total amount of flow in hours, suitable for time-sharing measurement (optional);

■ There are three Integrators, which can display the forward accumulation amount ,the reverse accumulation amount and the difference calculation amount respectively.. There is an internal power-down clock, which can record 16 power-down times. (optional);

■ With infrared handheld operator, 115KHZ communication rate, it can operate all functions of converter remotely without contact (optional).

Instrument Classification

1.According to the instrument structure, the vortex flowmeter can be divided into three categories, namely:

 ■ Full pipe type electromagnetic flow meter

Full pipe type electromagnetic flow meter

① No resistance parts in the measuring pipe, no pressure loss.

① With simple structure, the electromagnetic flowmeter measuring pipe can use different lining according to different qualifications, and the reliability is high.

■Separate type electromagnetic flowmeter

Separate type electromagnetic flowmeter

The converter and the  main body  are  installed  separately, which  is  convenient  for centralized installation and easy to read data.

■Plug-in type electromagnetic flowmeter

Plug-in type electromagnetic flowmeter

It is widely applicable to the flow measurement of large caliber conductive liquid medium in various industries.

①Wide nominal diameter range, suitable for all caliber pipes between DN150~DN3000.

②The sensor uses novel excitation mode, low power consumption, stable zero point and high precision. The flow range can reach 1500:1

Technical Parameters

(1) Electromagnetic sensors general specifications                                              Table 1


Nominal diameter (mm)

(Special specifications can be customized)

JB/T 9248-2015

Pipe type PTFE lining: DN10~DN600;

Pipe type rubber lining ink: DN40~DN2200

Plug-in type: DN150~DN3000

Flow direction

Range ratio

Repeatability error

Positive and negative


±0.1% of the measured value

Accuracy grade

pipe type: 0.5 grade, 1.0 grade; Plug-in: 1.5 grade, 2.0 grade

Measured medium temperature

Normal rubber lining: -20~+60°C

High temperature rubber lining: -20~+90°C

PTFE lining: -30~+100°C

High temperature tetrafluoro lining: -20~+180°C

Rated operating pressure

(high pressure can be customized)





Flow rate range

Conductivity range


The conductivity of the measured fluid is ≥5μs/cm

Signal output

4-20mA (load resistance 0~750Ώ), pulse/frequency, control level

Communication output

Power supply

RS485 communication MODBUS protocol, HART communication interface

220VAC or 24VDC

Required straight pipe length

Upstream ≥5DN, downstream ≥2DN

Connection mode

The flowmeter and the pipe use flange connection, and the flange meets the national standard: GB/T9115.1-2000

Explosion-proof grade

Protection grade

Ambient temperature

Relative temperature

Total power consumption


IP65, it can be customized up to IP68



Less than 20W

Meter Selection

(1) Product selection                                                                                                 Table 2




Full pipe type electromagnetic flowmeter


Plug-in type electromagnetic flowmeter

Nominal diameter                       




Integrated type


Separate  type

Electrode material


Stainless steel


Ti (titanium)






Pt platinum


Ni nickel

Output mode


No output





Lining material








Polyurethane rubber

Local display


No local display


Local display

Communication mode


No communication


RS485 communication (MODBUS protocol)


HART communication


GPRS wireless communication

Grounding ring


Without grounding ring


With grounding ring


Ground electrode

Upper limit flow


Upper limit flow (range) m3/h

Various types of electromagnetic flow meters

Installation Dimension

Flange connection type electromagnetic flow sensor

Separate flange connection type electromagnetic flow sensor

Electromagnetic Flowmeter Installation Precautions

1. Installation location

The pipe must be completely filled with liquid, which is critical, otherwise the flow display will be affected and measurement errors will occur. The pipe structure must be designed to ensure that the flow pipe is always filled with fluid.When the fluid is diverted or combined with solid particulate deposits,vertical installation is recommended, but for vertical installations,it need to follow the fluid direction from bottom to top to ensure that the pipe is full of fluid.

Installation position of electromagnetic flow meter

Avoid air bubbles. If air bubbles enter the flow pipe, the flow display will be affected ,and measurement errors will occur. When the fluid contains air bubbles, the pipe must be designed to prevent air bubbles from accumulating in the flow pipe. If there is a valve near the flow measuring pipe, place the pipe upstream of the valve as much as possible to avoid pressure reduction and bubble generation.

Electromagnetic flowmeter installed to avoid air bubbles

2. Installation direction

If the electrode is perpendicular to the ground, bubbles gathered at the top or deposits deposited at the bottom can cause measurement errors. Install the separate type flow pipe junction box and the integrated type converter on top of the pipe system to prevent water from entering.

3.  Straight pipe Sections Requirements and Environmental Requirements

Do not install anything near the flow pipe that may interfere with the magnetic field, the induced signal voltage, and the flow field distribution of flow pipe. In general,it is necessary to ensure a 5D of straight pipe section for the upstream and a 3D of straight pipe section for the downstream. If there are interference flow parts such as elbows and valves, the length of the straight pipe section required should be larger. It is highly recommended to install the valve at the downstream end to avoid flow fluctuations in the flow pipe and to avoid counting from the empty pipe status.

Installation diagram of electromagnetic flowmeter

4. Maintain stable fluid conductivity

Avoid installing the flowmeter in the position of uneven fluid conductivity. If chemicals are injected near the upstream end of the electromagnetic flowmeter, it may affect the flow display. To avoid this, it is recommended to inject chemicals to the downstream end of the flowmeter. If it must be injected from the upstream end, use a long enough straight pipe (approximately 5D) to ensure that the fluid is well mixed with the chemicals.


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