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Electromagnetic flowmeter classification and installation environment requirements description

Electromagnetic flowmeter classification and installation environment requirements
First, the principle of electromagnetic flowmeter
The electromagnetic flowmeter is a meter that measures the volumetric flow rate of a conductive liquid by using Faraday's electromagnetic induction law. In addition to measuring the volume flow of general conductive liquids, the sewage flow meter can also be used to measure the volumetric flow rate of strong corrosive liquids such as strong acid and alkali, and uniform liquid-solid two-phase suspension liquids such as mud, slurry and pulp. Widely used in petroleum, chemical, metallurgy, textile, paper, environmental protection, food and other industrial sectors and municipal management, water conservancy construction, river dredging and other fields of flow measurement. In the electromagnetic flowmeter, the conductive medium (the decisive substance) in the measuring tube is equivalent to the conductive metal rod in the Faraday test, and the two electromagnetic windings at the upper and lower ends produce a constant characteristic: the radiation of the wave particles. When a conductive medium flows, an induced voltage is generated, which is proportional to the flow rate of the fluid, thereby obtaining a flow rate value Q.

Second, electromagnetic flowmeter classification
The electromagnetic flowmeter is divided by the excitation current method, and has DC excitation, AC (power frequency or other frequency) excitation, low frequency rectangular excitation, and dual-frequency rectangular excitation. According to the classification of the output signal connection and the excitation (or power) connection, there are four-wire and two-wire systems.
Classified according to the combination of converter and sensor installation methods, there are split type and integrated type. (Pressure Transmitters)
Classified by flow sensor and pipe connection, flange type, clamp type (clamp type electromagnetic flowmeter), sanitary type (hygienic electromagnetic flowmeter), plug-in type (plug-in electromagnetic flowmeter), threaded connection (oil) Any connected high-voltage electromagnetic flowmeter).
According to whether the flow sensor electrode is in contact with the liquid to be tested, there are contact type and non-contact type.
According to the flow (unit: cubic meters per second) sensor structure classification, there are short tube type and plug type (plug-in electromagnetic flow meter). Vortex flowmeters are also known as vortex flowmeters or Karman vortex flowmeters. Comprehensively absorbing the advanced technology of developed countries and summarizing the research and production experience for many years, the products have been carefully designed to realize the product intelligence, standardization, serialization, generalization, production and mold, and ensure the beauty of product quality.
Classified by use, there are general-purpose, explosion-proof, sanitary, anti-intrusion type and submersible (open channel flowmeter) for open channel flow (unit: cubic meters per second).

Third, the electromagnetic flowmeter installation environment requirements
The electromagnetic flow sensor housing protection grade is generally IP65 (international GB4208 enclosure protection grade - dustproof and bumper water level), the main requirements of the installation environment are:
(1) The sensor should be installed in a dry and ventilated place to avoid moisture, water and flooding, and direct sunlight and rainwater should be avoided.
(2) It should be avoided as much as possible in places where the ambient temperature is too high. The electromagnetic flow of the integrated structure (unit: cubic meters per second) is also subject to the ambient temperature of the electronic components, which is lower.
(3) There should be no strong leakage current on the pipeline where the sensor is installed. It should be as far away as possible from the strong electrical characteristics: the equipment of the radiation of the wave particles, such as large electromechanical and large transformers, so as not to cause electromagnetic field interference;
(4) There should be no strong vibrations on the pipes or floors where the sensors are installed, especially integrated instruments;
(5) The location where the sensor is installed should take into account the space on site for maintenance. The electromagnetic flowmeter acts to produce a uniform DC or AC magnetic field. The DC magnetic circuit is realized by a magnet, which has the advantages of simple structure and less interference by the alternating magnetic field, but it is easy to polarize the electrolyte liquid in the measuring catheter, so that the positive electrode is surrounded by negative ions, and the negative electrode is surrounded by positive ions. That is, the polarization phenomenon of the electrode, and the internal resistance between the two electrodes increases, thus seriously affecting the normal operation of the meter.

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