Electromagnetic flowmeter how to use the water in the pool of water calibration

Case introduction

A brief analysis of how electromagnetic flowmeters are calibrated using water in the pool in water plants:

Electromagnetic flowmeters are widely used in sewage. The principle determines that it can only measure conductive liquids. Although it is The reliability and stability are much better than other types of flow meters. Like other flow meters, although the measurement range ratio of the electromagnetic flow meter is 30:1, it is higher than the vortex flow meter and the differential pressure flow meter. , but it also has limitations. When many customers order a meter, they often compare it with a water meter, thinking that it can measure very low flow rates. Under normal circumstances, it can only measure 0.1m/s. Below this flow rate, the electromagnetic flowmeter will It's hard to measure correctly. Therefore, it is necessary to clarify the flow range ratio at the initial stage of ordering. When ordering, you cannot order based on the original pipe caliber. You must determine the instrument caliber based on your actual flow rate.

For the measurement accuracy of water electromagnetic flowmeters in water plants to be verified using the clear pool volume method, a detailed verification test plan must first be formulated to actually measure the planar area of ​​the clear pool and water absorption well, deduct the clear pool and water absorption The area of ​​beams and columns in the well must be adjusted reasonably.

How does the water plant use the water in the pool to calibrate the electromagnetic flowmeter: ① Under normal water inflow conditions, enable the No. 1 clear pool and the No. 1 suction well, run the No. 3 to No. 6 water pumps, and close them The clear water pool connection valve raises the water level of the No. 2 clear water pool to about 3.5m, closes the water inlet valve of the No. 2 clear water pool, and closes the domestic water supply outlet valve. ② Wait for 10 minutes for the stabilization process, accurately record the water levels of the No. 2 clear water tank and the No. 2 suction well, record the accumulated volume of the domestic electromagnetic flowmeter, and use a high-precision steel ruler to manually measure the actual heights of the clear water pool and the water suction well. ③Wait for another 10 minutes and observe the water level changes in the clear pool and suction well. If the water level rises or falls, recheck the closing of each valve to ensure that the water level in each pool is stable. ④Close the main water inlet valve, stop the operation of water pumps No. 3 to 6, close the industrial water supply outlet valve, close the factory water supply valve, open the domestic water supply outlet valve, enable water pumps No. 1 to 2, and put them into normal operation. ⑤ After running for one hour, close the No. 1 to 2 water pumps and the domestic water supply outlet valve, open the main water inlet valve and the industrial water supply outlet valve, start the No. 3 to 6 water pumps, wait for 10 minutes for the stabilization process, and accurately record the No. 2 clean water pool and the No. 2 water pump. The water level in the suction well is recorded, and the accumulated volume of the electromagnetic flowmeter is recorded. At the same time, a high-precision steel ruler is used to manually measure the actual height of the clear water tank and the suction well, and the accuracy of each liquid level transmitter is reviewed.