How to Calibrate Magnetic Flowmeters

Flow meters go through several processes before they are finally ready for use; some include coil winding, electrode, and lining processing. These processes could lead to dispersion and errors in the flow meter.

Accordingly, a corrective process is then required to adjust and correct the error. Basically, there are two common methods of calibrating magnetic flow meters.

  • The Static Mass Method
  • The standard Meter Method

The Static Mass Method

The method known as static mass employs a liquid flow device that uses water, and relies on constant pressure from the environment, as well as a weighing system, a test pipeline, control equipment, and equipment to start and stop the test. To use this method, one must first install the mag meter in the pipeline and ensure that a water source is connected to it. The water flow from this source must be regulated with a flow-regulating valve to achieve a balance with the environmental pressure and to provide enough water to flow through the calibration pipeline. The commutator directs the water into the weighing container, where the pulse counter and timer are simultaneously started. During the weighing period, the temperature of the fluid is taken and the density of the fluid is measured at that temperature to determine its volume. Once this practical method is employed, values for weight, time, temperature, density, volume, and flow pulse can be obtained. These values can then be compared with standard data, the meter’s volume indication, or cumulative pulse number to calculate the meter constant and accuracy of the mag meter. The static mass method can achieve an accuracy level of 0.1%.

The Standard Meter Method

The standard meter method is comprised of a liquid flow standard device, a test pipeline, a fluid force, a control device, and a standard flow meter. The fluid continuously passes through the tested flow meter and standard flow meter before its output and values are compared. You could also use commutative flow values gotten after some time and compare them with the measurement of the new flowmeter to be tested. The gravimetric method is a more suitable option for liquid flowmeter calibration of water-based mag meters are then sent to a calibration laboratory. The standard flowmeter is based on the verification flow range or the verification flow point. This method is commonly used in the global flowmeter industry, and it is best for improving the verification efficiency and expanding the flow range.

With these two approaches to calibration, you can ensure the normal operation of your electromagnetic flow meters and deliver accurate measurements to your control system.

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