In the petrochemical, chemical, power, metallurgy, municipal, pharmaceutical and other industries, the technical difficulty and complexity of flow measurement are quite high, the study of flow measurement for improving product quality, reduce the operating costs of enterprises to solve energy conservation and environmental protection play an important role. Electromagnetic Flow Meter with no resistance, no pressure loss advantages, can fully reduce the resistance within the pipeline, in line with the requirements of energy saving, Electromagnetic Flow Meter in the industry has been widely attention. However, although the Electromagnetic Flow Meter has the above advantages, but also in terms of reliability and stability than most other types of flowmeter much better, but in the actual use of the process, or there will be some problems, the following instrument control Jun for everyone to list Electromagnetic Flow Meter in engineering applications need to pay attention to the main points.
According to the use of different flowmeter environment, the type of flowmeter is constantly changing, but how to choose the correct flow meter? The following is about the introduction (electric) magnetic flow meter knowledge. It is important to know how to choose the main knowledge.
Universal Electromagnetic Flow Meter products and special type of instrument can be classified from different angles.
According to the excitation current mode, there are DC excitation, AC (frequency or other frequency) excitation, low frequency rectangular wave excitation and dual frequency rectangular wave excitation.
According to the output signal connection and excitation (or power) connection standard classification, there are four-wire and two-wire system.
According to the converter and sensor assembly classification, there are separate and integrated.
According to the flow sensor and pipe connection method classification, a flange connection, flange clip connection, sanitary connection and threaded connection.
According to whether the flow sensor electrode and the measured liquid contact classification, contact and non-contact type.
Sort by flow sensor structure, with short tube type and insert type.
According to the use of classification, a general-purpose, explosion-proof, health type, anti-invasive type and diving type.
Electromagnetic Flow Meter (EMF) The measuring channel is a smooth straight pipe with a non-blocking flow detector. It is not easily blocked. It is suitable for the measurement of liquid-solid two-phase fluids containing solid particles or fibers such as pulp, coal slurry, pulp, Wait. EMF does not produce the pressure loss caused by the detection flow, the resistance of the instrument is only the same length of the pipeline along the resistance, energy-saving effect is significant, for the low resistance loss of large diameter water supply pipe is most suitable. The volumetric flow measured by the EMF is in fact not significantly affected by changes in fluid density, viscosity, temperature, pressure and conductivity (as long as above a certain threshold). Compared with most other flow meters, the front straight pipe requires less. EMF measurement range, usually 20: 1 ~ 50: 1, optional flow range. Full value The liquid flow rate can be selected from 0.5 to 10 m / s. Some models can be expanded and shrunk in the field as needed (for example, with a 4-digit potentiometer to set the meter constant) without having to be removed for offline calibration. EMF caliber range than other varieties of flow meter width, from a few millimeters to 3m. Can be measured positive and negative two-way flow, can also be measured pulse flow, as long as the pulse frequency is much lower than the excitation frequency. The instrument output is essentially linear. Easy to choose with the fluid contact material varieties can be applied to corrosive fluids.
EMF can not measure liquids with very low conductivity, such as petroleum products and organic solvents. Can not measure the gas, steam and contain more large bubbles of liquid. General type EMF due to lining materials and electrical insulation materials, can not be used for high temperature liquid; some models for too low temperature room temperature liquid, due to condensation outside the tube (or frost) and damage insulation