In addition to meeting the needs of on-site display, intelligent electromagnetic flowmeters can also output 4-20mA current signals for recording, adjustment and control.
In addition to meeting the needs of on-site display, intelligent electromagnetic flowmeters can also output 4-20mA current signals for recording, adjustment and control. They are now widely used in chemical industry, environmental protection, metallurgy, medicine, papermaking, water supply and drainage and other industries. Technical and management departments. In addition to measuring the flow of general conductive liquids, electromagnetic flowmeters can also measure the volume flow of liquid-solid two-phase flow, high-viscosity liquid flow, and salt, strong acid, and strong alkali liquids.
Structure form of intelligent electromagnetic flowmeter: 1. Sensor: The sensor is mainly composed of measuring catheter, measuring electrode, excitation coil, iron core, magnetic yoke and shell. a. Measuring conduit: It is composed of stainless steel conduit, lining and connecting flange. It is the carrier for measuring the on-site working conditions of the measured liquid. b. Measuring electrodes: A pair of electrodes installed on the inner wall of the measuring conduit, perpendicular to the axial flow direction, to generate signals from the measured liquid. c. Excitation coil: the upper and lower excitation coils that generate magnetic fields in the measurement catheter. d. Iron core and magnetic yoke: introduce the magnetic field generated by the excitation coil into the liquid and form a magnetic circuit. e. Shell: outer packaging of the instrument. 2. Converter: It is an intelligent secondary meter that amplifies the flow signal and processes it with the microcontroller. After calculation, it can display the flow rate and cumulative amount, and can output signals such as pulses and simulated currents for measurement or control of fluid flow. 3. Product assembly form: It is divided into two forms: integrated type and split type. a. Integrated type: The sensor and converter are installed together. b. Split type: The sensor and converter are installed separately, and a flow measurement system is formed by connecting cables. c. In order to adapt to the requirements of different medium measurements, there are many choices for the lining and electrode materials of the sensor.
The main advantages are as follows:
1. The sensor structure of the smart electromagnetic flowmeter is simple, there are no moving parts in the measuring tube, and there is nothing to hinder the flow of fluid. Throttle parts. Therefore, when the fluid passes through the flow meter, it will not cause any additional pressure loss, and it is one of the flow meters with the lowest operating energy consumption among flow meters.
2. It can measure the flow rate of dirty media, corrosive media and suspended liquid-solid two-phase flow. This is because the only flowing parts inside the measuring tube of the instrument are the lining and electrodes of the measuring tube that are in contact with the fluid being measured, and their materials can be selected according to the properties of the fluid being measured. For example, using polytrifluoroethylene or polytetrafluoroethylene as the lining can measure various corrosive media such as acids, alkalis, and salts; using wear-resistant rubber as the lining is particularly suitable for measuring wear and tear particles containing solid particles. Larger liquid-solid two-phase flows such as slurry and cement slurry, as well as various fibrous liquids and suspended liquids such as paper pulp.
3. The intelligent electromagnetic flowmeter is a volume flow measurement instrument. During the measurement process, it is not affected by the temperature, viscosity, density and conductivity (within a certain range) of the measured medium. Therefore, the electromagnetic flowmeter can be used to measure the flow of other conductive liquids only after being calibrated with water.
4. The output of the intelligent electromagnetic flowmeter is only proportional to the average flow velocity of the measured medium, and has nothing to do with the flow state (laminar flow or turbulent flow) under symmetrical distribution. Therefore, the measuring range of electromagnetic flowmeter is extremely wide., its measuring range can reach 100:1, and some even reach the operable flow range of 1000:1.
5. The electromagnetic flowmeter has no mechanical inertia and is sensitive in response. It can measure instantaneous pulsating flow as well as flow in both forward and reverse directions.
6. The diameter range of industrial electromagnetic flowmeters is extremely wide, from a few millimeters to several meters, and there are real-flow calibration equipment with a diameter of 3m in China, which provides a good foundation for the application and development of electromagnetic flowmeters. laid the foundation.
The main deficiencies that still exist in electromagnetic flowmeters are as follows.
1. It cannot be used to measure gas, steam and liquids containing a large amount of gas.
2. It cannot be used to measure liquid media with very low conductivity, such as petroleum products or organic solvents. Currently, electromagnetic flowmeters are unable to do anything.
3. Due to the limitations of the measuring tube lining material and electrical insulation material, ordinary industrial electromagnetic flowmeters cannot be used to measure high-temperature media; they cannot be used to measure low-temperature media without special treatment. To prevent condensation (frost) outside the measuring tube from damaging the insulation.
4. Electromagnetic flow meters are susceptible to external electromagnetic interference.
Hangzhou Economic Development Area，Hangzhou 310018，China
