The detailed introduction of electromagnetic flow sensor

Electromagnetic flow sensor can be defined as: it is made of conductive liquid flow induced electromotive force signal device. 1 magnetic circuit system

the role of the magnetic circuit system '331 is the uniform of dc or ac magnetic field. Dc excitation include constant excitation permanent magnetic field and constant excitation current magnetic field. This article adopts ac excitation, are using a 5 hz low frequency sine wave excitation. In a full package of electromagnetic flowmeter sensor measuring tube is composed of two exciting winding up and down, the full package of electromagnetic flow field current converter excitation circuit, leading to the excitation coil, magnetic field produce work. 2 electromagnetic flowmeter tube

measurement catheter under magnetic field, in the center of the sensor, fluid through, it must be able to undertake the work of fluid pressure, but also can afford excitation coil for measuring electrode electrostatic shielding effect, so the measuring tube material must be permeability, high resistivity and low thermal conductivity and has certain mechanical strength and generally adopt stainless steel, high strength glass fiber reinforced plastic, aluminum and other materials. The measuring tube is stainless steel material selection. 3 electromagnetic flow sensor

the lining of the work of one of the basic conditions for electromagnetic flowmeter, measurement of pipe wall in addition to the electrode area, the rest of the normal current is zero, the need to measure the wall insulation, it can protect induction electromotive force from the metal tube short circuit, therefore, the measurement of conductive metal pipe wall and the flange face lined with insulating lining 【 21, at the same time, the insulation lining also has the function such as corrosion resistance, abrasion resistance, here is lined with ptfe as insulation materials, under normal circumstances, the lining material with ptfe, rubber, PVC, polyurethane rubber, industrial ceramics, etc. Here with the ptfe has chemical performance is stable, resistance to boiling hydrochloric acid, sulfuric acid, aqua regia, strong alkali corrosion. Four electromagnetic flow sensor measurement of electrode

electrode direct contact with the liquid to be tested, so must be corrosion resistant, wear-resisting, leakproof, permeability on the structure. Three 316 l of measuring electrode material selection, applied to industrial wastewater, and the weak corrosive acid, alkali, salt solution, and the price is low. Electrodes for the measured medium corrosion resistance is to choose the material first consider factors, can choose other than the 316 l metal materials, such as steel, molybdenum acid hartz alloy B, C, titanium, tantalum, platinum-iridium alloy, etc. Grounding electrode selection and measuring electrode of the same material, can be achieved reliably and stably datum of conductive liquid as differential flow signal and signal converter connected, it forms a similar or roughly equal between the liquid and the polarization potential, the instrument can be stable output. 5 differential pressure sensor

in the electromagnetic flow sensor differential pressure sensor is a kind of used to measure the difference between the two pressure sensors, can be used for measuring gas flow rate and liquid level height. Measuring principle of differential pressure sensor, there are many, the resistance strain chip, chip, piezo-resistive type semiconductor strain, inductive, capacitive, resonant and capacitance acceleration type. Here it can be used to measure the function of the liquid level height, realize the liquid level measurement. Liquid level height measuring method, measuring the liquid surface pressure difference value, according to the liquid density, liquid level value conversion. One end of the differential pressure sensor in the measuring pipe to the bottom of the other side in measurement at the bottom of the tube, when the fluid to be at the full package, the differential pressure sensor to measure the difference between the liquid and gas pressure signal, through computational fluid can be obtained the current level value. Applied in the full GuanKaiFeng electromagnetic flowmeter, need to be aware of the matters, the differential pressure sensor can measure the dielectric is a conductive liquid and gas, and high precision. Otherwise, the liquid level in a small fluctuations, differential pressure sensor cannot perceive, cannot achieve accurate measurement of fluid level.