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Introduction to the installation of commonly used electromagnetic flowmeters

The standard meter method uses an electromagnetic flowmeter as a standard device in series with the flowmeter to be inspected, and can be verified by a static method or a dynamic method. By comparing the readings of the two flow meters, the error of the electromagnetic flowmeter to be tested is obtained.

Standard table flow meter standard device features:

1. Standard table method is suitable for measuring various fluids (including liquids and gases), and also for liquids of various viscosities.

2. The indication value is checked. The flow meter as the standard meter is installed in series with the flowmeter to be tested in the same closed pipeline system. Generally, there is no time measurement error.

3. The electromagnetic flowmeter as a standard meter can be the same as or different from the flowmeter to be tested.

4. When the flow meter is verified by the standard meter method, the airflow or liquid flow can be not cut off, so it is suitable for online verification, and is also suitable for the measurement standard for the closed pipeline.

5, the standard table method is easy to achieve automation, sealed and safe, does not pollute the environment.

6. Small size, light weight, simple device structure, convenient operation, easy transportation and installation, and low cost.

7. Standard meter flowmeters have low accuracy and poor stability, and often need to be compared regularly or irregularly to monitor their metering performance. The standard table has a shorter verification period. The bell jar method is poured into an upper open cylindrical reservoir filled with a sealing liquid (water or other liquid) due to an open container shaped like a bell jar. The bell jar floats in the sealed liquid, and the volume inside the bell jar is known. The gas flow rate can be obtained by measuring the volume of the gas that is sucked (or discharged) when the bell jar rises (or descends) during the measurement time interval. The bell jar device is a volumetric gas flow meter device. When the electromagnetic flowmeter is verified by the bell cover method, two methods of detecting the intake mode or the discharge mode may be employed. The working mode of the intake mode is higher than the residual pressure of the bell jar, and the flow rate is large. The working pressure of the exhaust mode is generally smaller than the residual pressure of the bell jar, and the flow rate is small. The bell jar has a water seal and an oil seal type. For a water-sealed bell jar, if the flow meter is used to check the flow meter, when the temperature of the meter is lower than the water temperature in the bell jar, the water vapor knot in the air should be considered. The error caused by exposure.

The bell jar method can only be used to measure air flow meters close to atmospheric pressure. The gas meter and the wet gas flow meter are usually verified by this method, and the flow range is small, and the flow meter with the upper limit flow rate of (3000-5000) m3/h can be verified. The accuracy of the device is 0.2%~0.5%.

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