How to choose electromagnetic flow meter?

Case introduction

　　Electromagnetic flow meters are flow meters that measure flow according to Faraday's law of electromagnetic induction. Electromagnetic flowmeter has the advantage of very small pressure loss, measurable flow range. The ratio of maximum flow rate and minimum flow rate is generally more than 20:1, applicable to a wide range of industrial pipe diameter, up to 3m, the output signal and the measured flow rate into a linear, high accuracy, can measure the conductivity ≥ 5μs/cm of acid, alkali, salt solutions, water, sewage, corrosive liquids and mud, slurry, pulp, pulp and other fluid flow. But it can not measure the flow of gas, steam and pure water.

　　If you want to choose a suitable electromagnetic flowmeter, you need to consider what factors

　　Caliber and range selection

　　The caliber of the transmitter is usually the same as the caliber of the piping system. If the piping system is yet to be designed, the caliber can be selected according to the range of flow mother and flow rate. For electromagnetic flowmeter, the flow rate of 2-4m/s is more appropriate. In special circumstances. Such as liquid with solid particles, taking into account the wear and tear, can choose the commonly used flow rate ≤ 3m / s, for easy to attach the wall of the fluid, can choose the flow rate of ≤ 2m / s, the flow rate is determined, according to determine the caliber of the transmitter.

　　The range of the transmitter can be selected according to two principles: first, the full range of the instrument is greater than the expected maximum flow rate value, and second, the normal flow rate is greater than 50% of the full range of the instrument to ensure a certain degree of measurement accuracy.

　　Lining selection

　　Electromagnetic flowmeter lining material correct selection method

　　Should be based on the measured medium corrosive, abrasive and temperature to select the lining material:

　　First, natural rubber (soft rubber)

　　1, better elasticity, abrasion resistance and tearing force

　　2, general resistance to weak acids, weak alkali corrosion

　　3, water testing, sewage

　　Second, acid-resistant rubber (hard rubber)

　　Resistant to hydrochloric acid, acetic acid, oxalic acid, ammonia, phosphoric acid and 50% sulfuric acid, sodium hydroxide, potassium hydroxide corrosion at room temperature, but does not resist the corrosion of strong oxidizers.

　　Can measure general acid, alkali, salt solutions.

　　Third, chloroprene rubber (Neoprene)

　　1, very good elasticity, high degree of tensile strength, good abrasion resistance

　　2, general low concentration of acid, alkali, salt solution corrosion, but not resistant to oxidizing media corrosion, and temperature requirements <80 ℃;

　　Can measure water, sewage, mud and slurry.

　　Fourth, polyurethane rubber (Polyurethane)

　　1, very good wear resistance

　　2, poor resistance to acid, alkali, temperature requirements <40 ° C

　　Measurement of neutral strong abrasion of coal slurry, mud and slurry

　　V. Polytetrafluoroethylene (PTFE)

　　1, boiling hydrochloric acid, sulfuric acid, nitric acid, aqua regia, concentrated alkali and a variety of organic solvents

　　2, good wear resistance, poor adhesive properties, temperature requirements -80 ~ +180 ℃;