Yj-lde series Electromagnetic current amount meter In the process of measuring the medium, the phenomenon of measurement value fluctuation will occur occasionally. Today, I will introduce some general reasons for the fluctuation of measured value.
Fluctuation reason 1: the liquid in the pipe is not full. Due to the insufficient back pressure or the poor installation position of the flowmeter sensor, the liquid in the measuring pipe of the electromagnetic flowmeter can not be filled up. The fault phenomenon is different due to the degree of non filling and the flow condition. If a small amount of gas appears stratified flow or wavy flow in the water pipe, the fault phenomenon is that the error of the flowmeter increases, that is, the flow measurement value and the real value If the flow is bubble flow or plug flow, in addition to the measured value is inconsistent with the actual value, the flow meter output shaking will occur due to the gas phase covering the electrode surface instantaneously; if the flow cross-section area of the horizontal pipeline increases in stratified flow, that is, the liquid is not full, the flow meter output shaking will also occur; if the liquid is not full, the flow meter output shaking will occur If the tube is in a serious condition and the liquid level is below the electrode, the output will exceed the full capacity.
Fluctuation reason 2: the liquid passing through the pipeline contains solid phase, and the liquid contains powder, particle or fiber and other solid. The possible faults include: ① slurry noise; ② electrode surface contamination; ③ conductive deposition layer or insulation deposit layer covering electrode or lining; ④ lining is worn or covered by sediment, and the flow cross-sectional area is reduced.
However, it is difficult to measure the temperature of the crystallizing fluid with the electromagnetic heat preservation tube when the temperature of the crystallizing fluid is easy to be measured by the electromagnetic heat preservation tube It causes a layer of solid on the inner wall, which leads to the error of electromagnetic flowmeter. Because there is no other better method, a kind of "ring" electromagnetic flow sensor with very short measuring tube length can be selected, and the heat tracing and insulation of upstream pipeline of flowmeter can be strengthened. Once the flow rate sensor is conveniently disassembled and removed, the method can be easily considered when disassembling the flow sensor.
Fluctuation reason 4: problems caused by improper material selection of electrode and grounding ring. The electromagnetic flowmeter with fault caused by material mismatch with measured medium has electrode and grounding ring. Besides corrosion resistance, electrode surface effect is the only reason for improper matching. The surface effects include: ① chemical reaction (formation of blunt film on the surface, etc.); ② electrochemical and polarization phenomena (generation of electric potential); ③ Catalysis (formation of gas mist on the electrode surface). In addition, the grounding ring may cause the error of electromagnetic flowmeter, but the influence degree is smaller.