Classification and field application of electromagnetic flowmeter
安装环境要求电磁流量传感器外壳防护等级一般是IP65(国际GB4208外壳防护等级——防尘防碰水级)，安装环境的主要要求是： I. Environmental requirements for the installation of electromagnetic flowmeters The protection level of the electromagnetic flow sensor housing is generally IP65 (International GB4208 enclosure protection level-dustproof and water-proof). The main requirements for the installation environment are:
(1) The sensor should be installed in a dry and ventilated place, avoiding humid and easily flooded places, and avoid direct sunlight and rain directly.
(2) Avoid installing in places where the ambient temperature is too high. The integrated structure of the electromagnetic flowmeter is also subject to the ambient temperature of the electronic components, which should be lower.
(3) There should be no strong leakage current on the pipeline where the sensor is installed, and it should be as far away as possible from equipment with strong electromagnetic fields, such as large electromechanical and large transformers, so as not to cause electromagnetic field interference;
(4) The pipeline or ground on which the sensor is installed should not have strong vibration, especially the integrated instrument;
(5) The place where the sensor is installed should consider the space for the staff to repair on site.
原理电磁流量计是利用法拉第电磁感应定律制成的一种测量导电液体体积流量的仪表。 2. Principle of electromagnetic flowmeter The electromagnetic flowmeter is a meter for measuring the volumetric flow of conductive liquid, which is made by using Faraday's law of electromagnetic induction. In the electromagnetic flowmeter, the conductive medium in the measuring tube is equivalent to the conductive metal rod in the Faraday test, and the two electromagnetic coils at the upper and lower ends generate a constant magnetic field. When a conductive medium flows through, an induced voltage is generated, which is proportional to the flow velocity of the fluid, and the flow rate value Q is obtained.
分类电磁流量计按激磁电流方式划分，有直流激磁、交流(工频或其他频率)激磁、低频矩形波激磁和双频矩形波激磁。 3. Classification of electromagnetic flowmeters Electromagnetic flowmeters are classified according to the excitation current, including DC excitation, AC (power frequency or other frequency) excitation, low-frequency rectangular wave excitation, and dual-frequency rectangular wave excitation. According to the system classification of output signal connection and excitation (or power) connection, there are four-wire system and two-wire system.
According to the converter and sensor assembly methods, there are split type and integrated type. (Pressure Transmitters)
Classified by the connection method of flow sensor and pipeline, there are flange type, clamping type (clamping electromagnetic flowmeter), sanitary type (sanitary electromagnetic flowmeter), plug-in type (plug-in electromagnetic flowmeter), thread connection (oil Any connected high-pressure electromagnetic flowmeter). Note:
According to whether the flow sensor electrode is in contact with the measured liquid, there are contact type and non-contact type.
According to the structure of the flow sensor, there are short tube type and plug-in type (plug-in electromagnetic flowmeter).
Classified by purpose, there are general-purpose, explosion-proof, sanitary, anti-invasion and submersible (open channel flow meters) for open channel flow measurement.