The type selection of electromagnetic flowmeter for sewage pipelines is very important in the use process. The after-sales problems caused by the wrong type selection are easy to occur in the sewage treatment industry. Here are some problems that are easy to occur when measuring the flow of electroplating sewage and some treatment methods.
In the electroplating industry, when measuring printing and dyeing wastewater with an acid medium, the flow will fluctuate, sometimes negatively. Treatment process: It is preliminarily judged as on-site interference, and the flowmeter has not been significantly improved after grounding treatment. It is learned that it is wastewater after printing and dyeing, and the medium has a certain adhesion. Flush the pipeline first, if there is no obvious improvement. Use a multimeter to detect the sensor and test the excitation coil. The resistance value jumps. Test the signal line voltage. The voltage is within the normal range. It is preliminarily judged that there is a problem with the sensor itself. After the sensor is replaced if there is still no obvious effect.
A megger can be used to supply power to the measuring electrode of the sensor. Increasing the voltage makes the protective film on the measuring electrode of the sensor break down, and the flow tends to be stable. It is judged that a protective film is generated on the tantalum electrode. It is judged that the measuring medium covers the electrode and the flow cannot be used normally. When the tantalum electrode measures ordinary water, an oxide film will appear, but this possibility will not occur again after the acid treatment. Based on the above judgment, the electromagnetic flowmeter can not be used normally due to the covering of electrodes caused by the adhesive substances of printing and dyeing wastewater on the site, so it is recommended to use an ultrasonic flowmeter.
Judgment steps: resistance value of the electromagnetic flowmeter and excitation coil is generally within 150 Ω, and signal line voltage is generally within 1V. For grounding, generally select the location where there are many metals. It is better to find a metal pipe deep in the ground as the grounding location. The grounding screw of the flowmeter includes the grounding screw of two flange plates and the grounding screw of the flowmeter head.
The above is a typical problem encountered by Wu Gong, an engineer of Hangzhou United Measurement, due to the wrong type selection of sewage pipe flowmeter. For the adhesive oily medium, the use of an electromagnetic flowmeter has certain limitations. According to the specific situation of the site, it is recommended to use a non-contact flowmeter. Through the professional and patient service of Hangzhou United Testing, Wu Gong has reduced a lot of losses for the company. We also hope that you can pay more attention to the selection of electromagnetic flow meters for sewage pipes to avoid difficult after-sales problems and unnecessary economic losses.