An electromagnetic flowmeter consists of two parts: a sensor and a converter. It works based on Faraday's law of electromagnetic induction and is used to measure the volumetric flow rate of conductive liquids with a conductivity greater than 5 μ S/cm. It is an inductive instrument for measuring the volumetric flow rate of conductive media. In addition to measuring the volumetric flow rate of general conductive liquids, it can also be used to measure the volumetric flow rate of strong corrosive liquids such as strong acids and alkalis, as well as homogeneous liquid-solid two-phase suspensions such as mud, slurry, and pulp. Widely used in industrial sectors such as petroleum, chemical, metallurgical, textile, papermaking, environmental protection, food, as well as municipal management, water conservancy construction, river dredging and other fields for flow measurement.

The measurement principle of electromagnetic flowmeter is based on Faraday's law of electromagnetic induction. The sensor part is composed of coils and electricityComposed of polar and insulating liningWhen measuring, the excitation coil in the sensor is energized to generate a magnetic field. When the conductive fluid passes through the magnetic field, a small induced electromotive force is generated due to the cutting force of the magnetic field lines. These small induced electromotive forces are collected by the electrodes and transmitted to the converter part of the instrument for signal amplification, correction and other operations. Then, they are converted intoThe corresponding flow data is ultimately displayed on the instrument.

When a conductive fluid flows through a magnetic field perpendicular to the flow direction, the conductive liquid induces an induced voltage E proportional to the average flow velocity. The induced voltage is detected by two electrodes in direct contact with the fluid, amplified, filtered, and shaped by a converter, and sent to the MCU to display and output control the instantaneous flow rate and cumulative flow rate.

E=KBVD In the formula: E - Induced voltage K - Instrument constant B - Magnetic induction intensity V - Average flow velocity inside the measuring tube D - Diameter of the flowmeter

The instrument structure is simple and reliable, with no movable parts and a long working life

No flow blocking components, no pressure loss or fluid blockage.

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

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

Different combinations of PTFE or rubber lining materials and electrode materials such as HC, HB, 316L, Ti can adapt to the needs of different media.

All digital processing, strong anti-interference ability, reliable measurement, high accuracy, and a flow measurement range of up to 150:1.

Full Chinese character menu operation, easy to use and simple to operate.

High definition backlit LCD display.

It has bidirectional flow measurement and bidirectional total accumulation function. It has three internal integrators that can display forward accumulation value, reverse accumulation value, and difference accumulation value respectively.

Output mode: bidirectional output function of current and frequency, and RS-485, MODBUS, HART interfaces.

Using SMD devices and surface mount technology, the circuit has high reliability.

Electromagnetic flowmeter and sensor technical data

Technical data of electromagnetic flowmeter converter

Flow measurement range:

Requirements of electromagnetic flowmeter for external environment:

1. Flow meters should be avoided from being installed in places with large temperature changes or high temperature radiation from equipment. If installation is necessary, insulation and ventilation measures must be taken.

2. The flowmeter should be installed indoors. If it must be installed outdoors, it should be protected from rainwater, waterlogging, and direct sunlight. Moisture and sun protection measures should be taken.

3. Flow meters should be avoided from being installed in environments containing corrosive gases, and ventilation measures must be taken when installation is necessary.

4. For the convenience of installation, maintenance, and upkeep, there should be ample installation space around the flowmeter.

5. The installation site of the flowmeter should avoid strong magnetic fields and vibration sources. If the pipeline vibration is large, there should be fixed pipe supports on both sides of the flowmeter.

Requirements for straight pipe section of electromagnetic flowmeter:

In order to improve the effects of eddy currents and flow field distortions, there are certain requirements for the length of the straight pipe sections before and after the installation of the flowmeter, otherwise it will affect the measurement accuracy (rectifiers can also be installed, avoiding installation near the regulating valve and half open valve as much as possible).

Requirements for process pipes: The flowmeter has certain requirements for the upstream and downstream process pipes of the installation point, otherwise it will affect the measurement accuracy.

The inner diameter of the upstream and downstream process pipes should be the same as that of the sensor, and should meet the requirement of 0.98DN ≤ D ≤ 1.05DN (where DN is the inner diameter of the sensor and D is the inner diameter of the process pipe). The process pipe and sensor must be concentric, with a coaxial deviation of no more than 0.05DN. The requirements for the bypass pipe are: to facilitate the maintenance of the flow meter, a bypass pipe must be installed for the flow rate. In addition, for heavily polluted fluids and flow meters that need to be cleaned and cannot be stopped, a bypass pipe must be installed.

Installation requirements for flow meters on pipelines:

Sensor grounding: In order to ensure reliable operation of the instrument, improve measurement accuracy, and avoid interference from external parasitic potentials, the sensor should have a good separate grounding wire with a grounding resistance of less than 10 Ω. If there is insulation layer or non-metallic pipeline in the pipeline connecting the sensor, grounding rings or built-in grounding electrodes should be installed on both sides of the sensor.

Grounding method on metal pipelines: If there is no insulation layer inside the metal pipeline, ground it according to the following diagram.

Grounding method on plastic pipes or insulated or painted pipes: Grounding rings or built-in grounding electrodes should be installed on both ends of the sensor to short-circuit the measured medium flowing inside the pipe to the ground and have zero potential. Otherwise, the electromagnetic flowmeter will not function properly.