The electromagnetic flowmeter is specially designed with a wide temperature Chinese liquid crystal display with backlight, which is fully functional, practical, intuitive and easy to operate, which can reduce the inconvenience caused by other electromagnetic flowmeters due to the English menu. In addition, the independent design of 4-6 multi-electrode structure, Mingyu automatic control further ensures the measurement accuracy, does not need to be grounded at any time, reducing the volume of the instrument and the trouble of installation and maintenance. Electromagnetic flowmeters can output 4-20mA current signals for recording, adjustment and control while meeting on-site display. At present, they are widely used in chemical industry, environmental protection, metallurgy, medicine, papermaking, water supply and drainage and other industrial technology and management departments.
The electromagnetic flowmeter is a high-precision measuring instrument, so it also requires tightness when used. Otherwise, inevitable errors will occur. So, what causes the error of the electromagnetic flowmeter? So let’s take a look.1. The liquid passing through the pipeline contains solids such as powder, particles or fibers in the solid phase liquid. The possible failures are as followsSlurry interferenceDirt on the electrode surfaceConductive build-up layer or insulating build-up layer covering electrodes or linings;The lining is covered by abrasion or deposits, and the flow cross-sectional area is reduced.2. The liquid in the tube is not full. Due to insufficient back pressure or poor installation position of the flow sensor, the liquid in the measuring tube is not full. Failure phenomena vary depending on the degree of unsatisfaction and flow conditionsWhen a small amount of gas is in a laminar or wavy flow in a tap water pipeline, the fault phenomenon is manifested as an increase in error, that is, the flow measurement value is inconsistent with the actual value; when the flow is bubble flow or plug flow, the fault phenomenon is except that the measured value is inconsistent with the actual value In addition, the output fluctuates because the gas phase instantly covers the electrode surface; when the gas phase part of the flow cross-sectional area in the horizontal piping laminar flow becomes larger, that is, when the degree of liquid not filling the tube becomes larger, the output swings also occur; The lower the liquid level is than the electrode, the more serious the liquid is filled up, and the output may be over-full.3. For the liquid with the possibility of crystallization, in the electromagnetic flowmeter, it is necessary to carefully use chemical substances that are easy to crystallize that can be measured normally under the condition of normal temperature. Since the fluid-conveying pipes have good thermal insulation performance, they will not crystallize during insulation, but it is difficult for the measuring tube of the electromagnetic flow sensor to implement thermal insulation. Therefore, when the fluid passes through the measuring tube, the temperature drops and it is easy to form a solid on the inner wall. Since the flowmeter measurement using other principles also has crystallization problems, in the absence of other good methods, a “loop” electromagnetic flowmeter sensor with a very short measuring tube length can be used to strengthen the upstream pipeline of the flowmeter through thermal insulation. Regarding the piping connection method, considering the ease of disassembly and assembly of the flow sensor, once it has crystallized, it can be easily disassembled and maintained.4. Problems caused by incorrect selection of the electrode and grounding ring materials. The material and the electromagnetic flowmeter that is in contact with the medium due to the mismatch of the measured medium have electrodes and grounding rings. In addition to the problem of corrosion resistance, as long as the electrode surface is incorrectly matched The effect can be. The surface effect is as followsChemical reaction (formation of a dull film on the surface, etc.);Electrochemistry and polarization phenomena (generation of electric potential);Catalysis (fogging on the surface of the electrode, etc.).In addition, the grounding ring also has these effects, but the degree of influence is small.The electromagnetic flowmeter is inspected regularly during use, to check the environment around the instrument, remove dust, prevent water and other substances from entering, check whether the wiring is good, whether a new strong electromagnetic field device is installed near the instrument, or whether a new wire crosses If the measuring medium of the instrument is easy to contaminate the electrode, or is easy to precipitate or scale in the measuring tube, it should be decontaminated and cleaned regularly.
Post time: 21-09-21