Three common faults of rotor flowmeter

The rotor flowmeter (float flowmeter) is a variable area flowmeter. The liquid flows in the flowmeter pipeline, causing the float in the pipeline to move upward. When the flow rate and flow rate are constant, the area between the float and the pipeline reaches a certain value. This area is proportional to the height of the float and is also proportional to the flow rate. The pointer of the pointer-type rotor flowmeter is displayed on the dial according to the height of the float through the rotation of the internal parts. The electronic head displays the intelligent calculation display of the circuit board.

1. The rotor flowmeter has large measurement errors:

1. Since the gas medium is greatly affected by temperature and pressure, it is recommended to use temperature and pressure compensation to obtain the true flow rate.

2. Due to long-term use and pipeline vibration and other factors, the floating flowmeter sensor magnet, pointer, counterweight, rotating magnet and other active parts are loose, resulting in large errors. Solution: You can first verify it by pushing the pointer by hand. First, press the pointer at the RP position to see if the output is 4mA and the flow display is 0%, and then verify it according to the scale in turn. If it is found to be inconsistent, the position of the component can be adjusted. Generally, professionals are required to adjust it, otherwise the position will be lost and it needs to be returned to the manufacturer for correction.

3. Installation does not meet the requirements: For vertical installation of rotor flowmeter, it should be kept vertical, with an inclination of no more than 20 degrees; for horizontal installation of rotor flowmeter, it should be kept horizontal, with an inclination of no more than 20 degrees; there should be no ferromagnetic objects in the 100mm space around the rotor flowmeter. The installation location should be away from the valve reducer, pump outlet, process pipeline turning port, etc. The requirement of 5D before and 250mm straight pipe section after should be maintained.
4. The large change in density of liquid medium is also a reason for large errors. Because the instrument is converted according to the density given by the user before calibration, and converted into the flow rate of water under the calibration state for calibration, if the density of the medium changes greatly, it will cause a large error in the measurement. The solution is to bring the density of the medium after the change into the formula, convert it into the error correction coefficient, and then multiply the flow measured by the flowmeter by the coefficient to convert it into the real flow.

2. Rotor flowmeter pointer jitter:

1. Severe pointer jitter: mainly due to medium pulsation, unstable air pressure or the pressure, temperature and flow of the gas operation state given by the user do not match the actual state of the rotor flowmeter, and there is a large difference causing the rotor flowmeter to over-range. 2. Slight pointer jitter: generally caused by medium fluctuations. It can be overcome by increasing damping. 3. Moderate pointer jitter: generally caused by the flow state of the medium. For gas, it is generally caused by unstable medium operating pressure. Voltage stabilization or flow stabilization devices can be used to overcome or increase the gas damping of the rotor flowmeter. 3. The pointer of the

rotor flowmeter stops at a certain position and does not move:

the main reason is that the rotor of the rotor flowmeter is stuck. Generally, when the rotor flowmeter is used, the valve is opened too quickly, causing the rotor to quickly impact the stopper upward, causing the stopper to deform and the rotor to be stuck. However, it is not ruled out that the rotor is stuck due to the non-concentricity of the rotor guide rod and the stop ring. When handling, the instrument can be removed, the deformed stopper can be removed and shaped, and check whether it is concentric with the guide rod. If it is not concentric, it can be corrected, and then the rotor can be installed, and the rotor can be pushed by hand. It can be felt that the rotor is unobstructed up and down without obstruction. In addition, when installing the rotor flowmeter, it must be installed vertically or horizontally, and it cannot be tilted, otherwise it is easy to cause the meter to be stuck and bring errors to the measurement.