Description of maintenance points of electromagnetic flowmeter in pipeline measurement

Electromagnetic flowmeter If the measured medium is relatively dirty for a long time, the electromagnetic flowmeter will produce fouling on the electrode after working for a period of time. When the conductivity of the fouling substance is different from the conductivity of the measured medium, measurement error will occur. The adhesion of sludge and oil to the electrodes will also cause the instrument output to oscillate and drift. Therefore, in this case we need to regularly maintain and clean the electromagnetic flowmeter electrodes. What are the main points of maintenance of electromagnetic flowmeters in pipeline measurement?
 
1) Platinum surface contamination seriously forms an oxide film. The surface of platinum or gold can be polished with toothpaste, then washed with pure water, and then immersed in 3.5MOL/L potassium chloride solution for 6 hours.
 
2) For inorganic contamination, the electrode can be immersed in 0.1 mol/L dilute hydrochloric acid for 30 minutes, washed with pure water, and immersed in 3.5 MOL/L potassium chloride solution for 6 hours before use.
 
3) For the contamination of organic oil and oil film, the surface of platinum or gold can be washed with detergent and then washed with pure water, and then immersed in 3.5MOL/L potassium chloride solution for 6 hours.
 
4) Dipping in 4% hydrogen fluoride solution for 3 to 5 s, taking it out and rinsing with distilled water, then immersing it in 0.1 mol/L hydrochloric acid solution for several hours, rinsing with distilled water, and calibrating.
 
Precautions for measuring wastewater with electromagnetic flowmeter
 
Waste water is used for pipeline discharge. Most of them choose electromagnetic flowmeter to measure. Because there is no obstacle in the sensor, there is no fear of debris in the medium, but it is necessary to pay attention to the medium must be full. If the tube is not full, it must be piped to sink a section. Pipeline to ensure that the flowmeter is full. Note that the flowmeter cannot be installed at the drain of the pipe. The length of the straight pipe should meet the requirements of the flowmeter.
 
Wastewater is used for ditches. Most of them use ultrasonic open channel flowmeters. A measuring tank is installed in the discharge port. An ultrasonic probe is installed directly above the tank, so that the flow rate of the flowing water can be measured. The meter is generally powered by 24V. : 4-20MA.
 
Electromagnetic flowmeters are primarily used to measure volumetric flow in conductive liquids and slurries in closed conduits.
 
The electromagnetic flowmeter measurement principle is based on Faraday's electromagnetic induction law. The pipeline electromagnetic flowmeter consists of a sensor and a converter. The sensor is mounted on the measuring pipeline. The converter can be combined with the sensor and is called an integrated electromagnetic flowmeter. When it is installed within 30 meters or within 100 meters of the sensor, the connection between the two is called a separate electromagnetic flowmeter.
 
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, an induced voltage is generated. The two electrodes inside the pipe measure the induced voltage generated. The measuring tube is electromagnetically isolated from the fluid and the measuring electrode by a non-conductive inner liner (rubber, Teflon, etc.).
 
Electromagnetic flowmeters are used to measure the flow of conductive fluids in the departments of tap water, steel, petroleum, chemical, electric power, industry, water conservancy, water resources, water resources, etc., and can also measure corrosive conductive liquids such as acids, alkalis, and salts.