Wuxi oubai instrument technology co. LTD
Focus on flow meter development
Iso9001-2000 international quality system certification
 Hello, welcome to visit wuxi oubai instrument official website! We serve you wholeheartedly! 
Sitemap               Message          Contact
Online customer service
 Work Time
Mon to Fri :8:30-17:30
Sat to Sun :9:00-17:00
 Contact Details
 Work Time
Mon to Fri :8:30-17:30
Sat to Sun :9:00-17:00
 Contact Details

Structure and characteristics of electromagnetic flowmeter

Issuing time:2018-01-30 09:31

Structure and characteristics of electromagnetic flowmeter

Instrument is introduced

Electromagnetic flowmeter (EMF) is a new type of flowmeter developed rapidly with the development of electronic technology from 1950s to 1960s. The electromagnetic flowmeter is an instrument which USES the principle of electromagnetic induction to measure the flow rate of the conductive fluid according to the electromotive force induced when the conductive fluid passes through the external magnetic field.


The structure of electromagnetic flowmeter is mainly composed of magnetic circuit system, measuring pipe, electrode, shell, lining and converter.

Magnetic circuit system: its function is to produce a uniform dc or ac magnetic field. Dc magnetic circuit to achieve with a permanent magnet, its advantage is simple structure, the ac magnetic field interference is small, but it is easy to make by measuring the electrolyte liquid polarization in the ducts, the positive electrode is surrounded by negative ion, negative electrode is surrounded by positive ions, the electrode polarization, and lead to increased internal resistance between two electrodes, thus seriously affect the normal work of the instrument. When the pipe diameter is large, the permanent magnet is also large, bulky and uneconomical, so the electromagnetic flowmeter generally USES an alternating magnetic field, and is generated by 50HZ power-frequency power supply.

Measuring catheter: the function of the measuring catheter is to let the conductive liquid pass through. In order for the magnetic flux to be shunt or short-circuit when the magnetic field line passes through the measuring catheter, the measuring catheter must be made of materials with non-magnetic conductivity, low electrical conductivity, low thermal conductivity and certain mechanical strength, and non-magnetic stainless steel, glass fiber reinforced plastics, high-strength plastics, aluminum and so on.

Electrode: the function of the electrode is to elicit an inductive potential signal proportional to the measured value. The electrodes are generally made of non-magnetic stainless steel and are required to be flush with the lining so that the fluid can pass unimpeded. It should be installed in the vertical direction of the pipe to prevent sediment accumulation on it and affect the measurement accuracy.

Case: made of ferromagnetic material, it is the outer cover of the distribution system excitation coil and isolates the interference of external magnetic field.

Lining: a complete electrical insulating lining is provided on the inside of the measuring conduit and on the flange sealing surface. It directly contacts with the measured liquid, and its function is to increase the corrosion resistance of the measuring pipe and prevent the inductive potential from being short-circuiting by the metal measuring pipe wall. Lining materials for corrosion resistance, high temperature resistance, wear - resistant polytetrafluoroethylene plastics, ceramics and so on.

Converter: the induction potential signal generated by liquid flow is very weak, which is greatly affected by various interference factors. The role of converter is to amplify the induction potential signal and convert it into a unified standard signal and suppress the main interference signal. Its task is to convert the induction potential signal Ex detected by the electrode into a unified standard dc signal through amplification.

1. The measurement is not affected by changes in fluid density, viscosity, temperature, pressure and conductivity;

2. There are no obstructing flow parts and no pressure loss in the measuring pipe, and the requirements for the straight pipe section are relatively low. It has unique adaptability to the measurement of slurry.

3, reasonable selection of sensor lining and electrode materials, that is, with good corrosion resistance and wear resistance;

4. The converter adopts novel excitation mode with low power consumption, stable zero point and high accuracy. Flow range up to 150:1;

5. The converter can be of the same shape or separated type with the sensor;

6. The converter adopts a 16-bit high-performance microprocessor, 2x16LCD display, convenient parameter setting and reliable programming;

7. The flow meter is a two-way measurement system with three integrators: total forward, total reverse and total difference; Can display positive and negative flow, and has a variety of output: current, pulse, digital communication, HART;

8. The converter adopts surface mounting technology (SMT), with self-inspection and self-diagnosis functions;

9. The measurement accuracy is not affected by the changes of fluid density, viscosity, temperature, pressure and conductivity, and the sensor induced voltage signal has a linear relationship with the average flow velocity, so the measurement accuracy is high.

10. Measure the unimpeded flow in the pipe, so there is no additional pressure loss; There are no moving parts in the measuring pipe, so the sensor life is extremely long.

11. As the induced voltage signal is formed in the whole space filled with magnetic field, which is the average value of the pipeline surface, the straight pipe section required by the sensor is shorter, and the length is 5 times the diameter of the pipeline.

12. The converter adopts the latest and most advanced MCU and SMT, with reliable performance, high precision, low power consumption, stable zero point and convenient parameter setting. Click Chinese LCD to display cumulative flow, instantaneous flow, flow rate, flow percentage, etc.

13. Two-way measurement system can measure forward flow and reverse flow. Special production process and high quality materials are adopted to ensure the stability of product performance in a long time.

Share to:








Customer Cases

Customer Cases

Customer Cases

Product name:
electromagnetic flowmeter Date of purchase: May 2015 Purchase quantity: 8 sets
Product name:
vortex street flowmeter
Date of purchase: July 2016
Purchase quantity: 5 sets
Wuxi Shenli
Buy product name:
differential pressure transmitter
Date of purchase: March 2017
Purchase quantity: 7 sets
Walter machinery
Purchase product name:
digital display table
Date of purchase: April 2018
Purchase quantity: 11 sets
Wanyuan environment
Wuxi oubai instrument technology co., ltd. has a number of excellent r & d team, and with jiangnan university, wuxi business school and other universities and enterprises cooperation. The company has a sound sales and after-sales service system and efficient marketing team; The product sales coverage keeps growing all the year round.
In the industry, it is one of the production and sales enterprises of flow meters with a complete range of products and a large scale, which produces good electromagnetic flowmeters, liquid flowmeters, gas flowmeters, etc.
The company focuses on user practice and product research and development, and has obtained a number of patents and research and development results, and has mature experience in the research and development, design, manufacturing and installation of flow meter equipment in various industries.
7 * 24-hour service system, one year guaranteed, so that you at any time product problems we can solve as soon as possible for you, to ensure the interests of customers;
Set up a group of professional teams, engaged in design, production, sales and installation services;
To the well-known large projects have done supporting, set up many classic cases;
index | electromagnetic flowmeter | vortex street flowmeter | open channel flowmeter | product center | case analysis | about our | news center | contact us
Address: 11-2-4, jinshan fourth branch road, beitang district, wuxi city, jiangsu province Hot line: 0510-89052999 0510-82358878 The true: 0510-89052999 Hand machine: 18661273788
Q Q: 630441747
Mail box: sales@wxobai.com
Mail editor: 214000
Technical support: le shi tong