On the vortex flowmeter common faults and treatment methods
Time: 2024-07-09
Vortex flowmeter in daily use will inevitably encounter some common glitches, for these faults Supmea Instrumentation staff contact to give the following points, I hope to help you.
Project Overview
- 1.Failure phenomenon: vortex flowmeter to measure the saturated steam flow, the installation of RTD Ptl00 to measure the steam temperature, found that the flowmeter head of steam temperature, pressure are low, resulting in the display of steam mass flow rate is also low. Reason analysis: Because the flowmeter head display of saturated steam pressure is directly derived from the steam temperature, measured temperature is low, will inevitably lead to low pressure. Therefore, the problem of inaccurate temperature measurement should be solved.
Treatment:
- (1)Remove the RTD wiring on the flowmeter side, measure the resistance value of RTD with multimeter and compare it with the temperature control table, then we can judge the problem in the flowmeter or RTD. If the measured value is not low, then the problem is in the flowmeter: if the measured resistance is low, then the problem is in the RTD, may be due to the RTD itself resistance temperature correspondence is inaccurate, but also may be due to the RTD and casing installation problems, resulting in the RTD itself and the temperature of the steam temperature difference.
- (2)Check the field temperature measurement RTD to the instrument along the way whether the installation of variable frequency equipment, transformers or high-power motors, etc. will send out a strong interference of different frequencies, resulting in resistance value measurement results in deviation. At this time, the thermal resistance can be appropriate parallel connection filter capacitor, the AC interference noise short circuit. After checking, it is found that it is due to the measurement error caused by insufficient insertion depth when the RTD is installed. After reinstalling the RTD, the measurement is correct.
- 2.Failure phenomenon: in the use of vortex flowmeter to measure the flow of superheated steam, feel that the measurement results have obvious deviations, in the flowmeter carefully check the flowmeter to determine the meter instrumentation system (flow sensors, display instrumentation, temperature instrumentation and pressure instrumentation) is completely normal. Reason analysis: If the site pipe insulation is not good, superheated steam flow resistance loss is not large (not too many valves and other resistance pieces on the pipeline), due to the rapid reduction in temperature and the possibility of superheated steam by becoming saturated steam, and condensation. At this point, if the meter is still according to the superheated steam law on the density of the operation will bring additional errors, and the emergence of condensate in the pipeline, but also to make the measurement results of the deviation further increase. Treatment: carefully check the flow meter installation pipeline insulation is good, if the pipeline is not heated or part of the pipeline insulation needs to be re-insulated pipeline. Re-insulation of the pipeline after processing, the instrument measurement results show correct. 3. Failure phenomenon: vortex flowmeter measurement used to measure the gas flow, the installation of the guard after the measurement readings found to be unstable. Reason analysis: may be due to site installation problems, meter selection is not allowed, the instrument parameters are set incorrectly.
Treatment:
- (1)Make on-site observations that the sealing gasket was installed correctly. Sealing gaskets that are too small or that are not installed concentrically may cause erratic readings.
- (2)Flow meters are selected incorrectly. If the selection of the wrong type, commonly used flow in the nonlinear region, or even near the critical dead zone, then there may be flow fluctuations. If the process conditions allow, increase the flow rate, if the flow rate is stabilized, then replace the flowmeter with a smaller diameter.
- (3)By experience, or according to the nature of the fluid and working pressure, temperature, etc. to determine whether the fluid exists liquid and gas two-phase flow. Vortex flowmeter can only measure single-phase flow, can not measure two-phase flow, which is determined by the working principle of vortex flowmeter. If the liquid and gas two-phase flow can be installed in the upstream end of the flowmeter degasser.
- (4)Flowmeter parameter settings are incorrect, intelligent instrumentation, its parameter configuration must be correct. After checking found to be due to the installation of the sealing gasket selection is not appropriate to cause unstable flowmeter readings. Replacement of the appropriate sealing gasket after the fault disappears.
- 3.Fault phenomenon: A vortex flowmeter measuring gas flow used to read normally, and suddenly showed incorrect readings. After carefully checking the flowmeter, the flowmeter instrumentation system (flow sensor, display instrument, temperature instrument and pressure instrument) was judged to be completely normal. Reason analysis: may be due to gas corrosion, abrasion or gas impurities in the gas, viscous substances winding or adhesion, so that the flowmeter generator surface changes in the state of the body, and thus the formation of vortex impact, the flow rate and the vortex frequency of the corresponding relationship between the changes that have occurred, thus changing the display value of the flowmeter, the instrument accuracy is greatly reduced.
- Treatment: Check and clean the vortex flowmeter probe. Through the disassembly inspection found that the flowmeter probe is wrapped in plastic, after processing the readings show normal.Supmea Instruments vortex flowmeter production for many years, if you encounter any problems in the process of vortex flowmeter selection, installation, use, maintenance, you can contact Supmea Instruments vortex flowmeter manufacturers staff, we are ready to answer for you.