Sewage flowmeter maintenance methods in daily use

Case introduction

Discuss and analyze the maintenance methods of sewage flow meters in daily use

Flow meters are one of the major categories of process automation instruments and devices. They are widely used in metallurgy, electric power, coal, chemical industry, Various fields of the national economy such as petroleum, transportation, construction, textiles, food, medicine, agriculture, environmental protection and people's daily life are important tools for developing industrial and agricultural production, saving energy, improving product quality, and improving economic efficiency and management level. It occupies an important position in the national economy. But users must also pay attention to what aspects need to be paid attention to in daily maintenance?

1: Manual zeroing method: refers to using a multimeter to manually zero the differential pressure transmitter. This method can be used when the zero point of the differential pressure transmitter has a slight drift. The method is as follows: Differential There are two signal lines, positive and negative, on the pressure transmitter. Remove one of them, adjust the multimeter to the 4-20mA DC range, and string the multimeter in. The differential pressure transmitter has a zero adjustment screw (marked zero on it). (Zero adjustment button). When adjusting clockwise, the current will increase, and counterclockwise will decrease. When the multimeter displays 4mA, it means that the zero point has been adjusted properly. 2: Valve switching sequence during condensation (mainly for steam): During normal operation, the middle valve of the three-valve group is closed, and the valves on both sides are open. If it is necessary to drain or re-condensate, first close the valves on both sides, and then open the middle valve. Finally, open the root drain valve for draining. If condensation is complete, you want to close the middle valve, and then slowly open the valves on both sides, so that the system is in normal operation. 3: When the measurement medium is steam, online zero adjustment should be performed, because there may be a slight height difference in the condensation plate during installation. When the flow rate of the measured fluid is small, the height difference will have a greater impact on the flow rate. (1 centimeter of water column is 100Pa) Maintenance method: 1. The probe of the vortex flowmeter should be cleaned regularly. During the inspection, it was found that the detection holes of some probes were blocked by dirt or even wrapped in plastic sheets, which affected normal measurement. 2. Since the determination of the K coefficient is very important in the entire process of the vortex street, the accuracy of the K coefficient directly affects the accuracy of the loop. The replacement of instrument parts and the wear and tear of the process pipeline may affect the K coefficient. However, Dongfang Chemical Plant lacks the means and capabilities for calibration and can only send out calibration. Due to the influence of process operation, it takes 5 or 6 days for calibration to remove the vortex street from the pipeline and send it out. It is difficult to meet the technical requirements, so it cannot be determined. K factor. This year, through the transformation of the flow meter room, although the calibration conditions for smaller-diameter vortex streets have been met, it is still unable to do anything for larger-diameter vortex streets. In the future, attention should be paid to the on-site calibration method of vortex streets, using standard frequencies and portable ultrasonic waves. Flowmeter, measure the instantaneous flow rate in the pipeline and the pulse output frequency of the sensor, calculate the K coefficient on site 3, and install the probe in a humid environment. It should be dried regularly or treated with moisture-proof treatment. Since the probe itself is not moisture-proof, its operation will be affected if it gets damp. 4. Regularly check the grounding and shielding conditions to eliminate external interference. Sometimes indication problems are caused by interference. 5. Instrument dataThe management should pay enough attention to facilitate future work.

Keywords: sewage flow meter, Fujian sewage flow meter, Fujian electromagnetic flow meter, sewage treatment flow meter, water measurement flow meter, split electromagnetic flow meter, large diameter electromagnetic flow meter