Smart Electromagnetic Flowmeter

Overview

DWP series pipeline type intelligent electromagnetic flowmeter is an electromagnetic induction flowmeter, designed according to JB/T9248-999 "Electromagnetic Flowmeter", suitable for flow calculation of conductive liquid with conductivity greater than 5us/cm; nominal diameter range is 5 To 3000, it is a series of electromagnetic flowmeter products integrating intelligence, small and lightweight integration, multi-function, high precision and high reliability. It consists of two parts: sensor and smart converter.

DWP electromagnetic flowmeter has a wide range of uses. It can output a standard current signal (4-20mA) in line with the HART communication protocol while meeting the on-site monitoring and display, for recording, adjustment, and control; it can be widely used in chemical industry, environmental protection, and textile industry. , metallurgy, mining, medicine, papermaking, water supply, food, sugar, brewing and other industries for liquid flow measurement of conductive media in process pipelines; in addition to measuring general conductive liquid, according to the special needs of users, it can also measure conductive liquid-solid two-phase Flow, flow of high viscosity liquids and liquids such as salts, strong acids, and strong alkalis.

The structures

(1) Sensor:

The sensor is mainly composed of a measuring catheter, a measuring electrode, an excitation coil, an iron core, a magnet and a housing.

Measuring conduit: It is composed of stainless steel conduit, lining and connecting flange, and is the carrier for on-site measurement of the liquid to be measured.

Measuring electrodes: a pair of electrodes installed on the inner wall of the measuring conduit, perpendicular to the axial flow direction, so that the measuring liquid generates signals.

Excitation coil: The upper and lower excitation coils that generate a magnetic field in the measurement catheter.

Iron core and magnetism: The magnetic field generated by the excitation coil is introduced into the liquid and forms a magnetic circuit.

Shell: the outer packaging of the instrument.

(2) Converter:

It is an intelligent secondary meter, which amplifies the flow signal and calculates it with a single-chip computer to display the flow and cumulative amount, and can output pulse, analog current and other signals for the measurement or control of fluid flow.

(3) Product assembly form:

It is divided into two forms: integrated type and split type.

Integrated type: The sensor and converter are installed in one piece.

Split type: The sensor and converter are installed separately, and the flow metering system is formed by connecting cables. In order to meet the requirements of different media measurement, the lining and electrode materials of the sensor can have many choices.

Working principle

The working principle of electromagnetic flowmeter is based on Faraday's law of electromagnetic induction. That is, when the conductive liquid flows through the electromagnetic flowmeter, an induced electromotive force will be generated in the conductor. The induced electromotive force is proportional to the flow rate of the conductive liquid, the magnetic induction intensity, and the width of the conductor (inner diameter of the flowmeter), as shown in the figure.

The induced electromotive force is detected by a pair of electrodes on the wall of the flowmeter, and the flow rate can be obtained through calculation.

The induced electromotive force equation is: E=KBVD

In the formula: E induced potential; D measuring tube inner diameter;

B magnetic induction intensity; V average flow velocity;

K is a coefficient related to the magnetic field distribution and axial length.