Electromagnetic flowmeter has bubble noise solution explained

Electromagnetic flowmeter is to measure the volume flow rate in the closed pipeline in the conductive liquid and slurry, including acid, alkali, salt and other strong corrosive liquids. Electromagnetic flowmeter in the iron and steel industry cooling water measurement in the false alarms occur mostly by bubbles rubbing over the electrode, the formation of a short period of time, the induction signal is zero, which is a kind of cavitation phenomenon. So, how can the bubble noise problem be avoided?

• 1、Increase the meter damping time can effectively solve the impact of this pulsating bubble noise, but also brings the disadvantage of slow response, that is, when the real flow fluctuations, the meter response is very slow. This requirement for sensitive control of cooling water systems is undoubtedly a difficult problem. In order to solve this problem, intelligent electromagnetic flowmeter can use software logic to determine that the method of gross error processing. In the event of such a failure, by adjusting the flow of insensitive time and change the magnitude of the limit of these two conditions to determine whether the flow of change, or bubbles rubbing over the electrode. If it is not a bubble rubbing the electrode noise, the CPU according to the normal sampling, computing and digital filtering; if it is determined that the bubble noise, cut off the measured value, maintaining the previous flow measurement value. In this way, the normal flow measurement during the damping time is still 3 ~ 6 s. Only in the bubble noise, according to the length of the pulse width setting will be insensitive to the time will be longer, the system control time will also be longer.

• 2、Reasonable setting of the flowmeter damping time and function, can also be resolved to appear bubble noise measurement of false alarms. Damping time selection is based on the flow signal in the occurrence of bubble noise pulse width to select. Generally should take the damping time for the bubble noise pulse width of 3 to 5 times. Such as bubble noise pulse width is 10s, damping time should be taken 30~50s. specific selection should be based on the required control accuracy, 3 times the pulse width control error in 5%, 5 times the pulse width control accuracy is higher than 1%.
• 3、Should be installed to meet the electromagnetic flowmeter upstream straight pipe length requirements, standardize the installation of the instrument, choose to stay away from the heat source of the installation site, the rational use of pipeline flow rate, the use of high finish PFA fluorine plastic lining and high purity alumina industrial ceramic conduit. These measures will help prevent or minimize the occurrence of vortex and gas separation. In other words, it is possible to avoid the problem by improving the manufacturing process of the sensor, improving the environmental conditions and installation conditions of the instrument, and adopting measures such as installing an air vent upstream of the instrument.

Above is the electromagnetic flowmeter manufacturer Supmea on the bubble noise solution details, there are any related issues can be directly online consultation with us.