The mass flow meter is a high-precision and high-reliability flow meter that can directly measure the mass flow rate and density of the medium and indirectly measure the temperature of the medium. However, during use, the mass flow meter may also experience some malfunctions, affecting its normal operation. This article will introduce you to common mass flow meter failures and their solutions.

Out of tolerance problem

In the process of using mass flow meters, out-of-tolerance problems often occur. Even if calibration has been performed, the measurement results are still incorrect. This may be due to the sensor not being installed on the same axis of the pipe, or due to stress issues in the pipe causing the sensor to measure inaccurately, resulting in damage to the sensor. In order to avoid this problem, attention should be paid to the installation position of the sensor and the control of pipeline stress to ensure that the sensor can correctly measure the mass flow rate of the fluid.

The curve fluctuates greatly

During the use of mass flow meters, sometimes the problem of large curve fluctuations occurs, which may be caused by factors such as pipeline vibration. At this time, we can adjust the flow rate by controlling the valve, or set a small flow cutoff to reduce the impact of pipeline vibration on the mass flow meter.

Virtual metering phenomenon

Sometimes, the mass flow meter will have a virtual measurement phenomenon, and the accumulated number will change even if there is no flow rate. This may be caused by the flange being asymmetrical during installation, causing stress in the pipe. In order to avoid this problem, attention should be paid to the symmetry of the flange when installing the mass flow meter to ensure that the pipeline can run smoothly.

Electric control valve leaks

If the electric control valve behind the mass flow meter is leaking, it may be because the nominal pressure of the electric control valve is less than the system pressure. In order to solve this problem, the electric control valve whose nominal pressure is greater than the system pressure should be replaced to ensure that the valve can be closed normally.

Regular inspection

During the use of the mass flow meter, the operating parameters should be checked regularly for changes. If there is a large deviation from the actual value, the zero flow calibration should be re-calibrated according to the instructions in the instruction manual to ensure the accuracy and stability of the measurement data. When calibrating, attention needs to be paid to closing the rear valve to ensure that the flow fills the pipe.

Gas-liquid two-phase and excitation current over-limit problems

If the gas-liquid two-phase and excitation current exceed the limit during use of the mass flow meter, the measurement data may be inaccurate or the measurement may not be normal. In order to solve this problem, we need to understand the cause and solution of the problem.

Gas-liquid two-phase refers to the situation where gas and liquid exist at the same time in the flow meter pipe. This can lead to inaccurate measurement data because gas and liquid flow at different speeds and densities in the pipe, causing the sensor to be unable to accurately measure flow. In addition, gas-liquid two-phase flow may also cause pipeline vibration and noise, further affecting measurement accuracy.

The excitation current over-limit problem means that the sensor excitation current exceeds its rated value during use. This may cause the sensor to malfunction, affecting measurement accuracy and stability.

The following is a method to solve the problem of gas-liquid two-phase and excitation current exceeding the limit:

1. Increase system pressure. Increasing system pressure reduces the presence of gas, thereby reducing the effects of the gas and liquid phases. However, this approach may increase the cost and energy consumption of the system.

2. Adjust the valve. After adjustment, the valve can control the flow rate and flow rate and reduce the influence of the gas and liquid phases. In addition, setting up small flow cutoff and reducing pipeline vibration can also reduce the influence of gas and liquid phases.

3. Replace filter. If gas-liquid two-phase flow occurs, it may be caused by the filter screen causing gas-liquid two-phase flow in the pipeline. Replacing the filter with a suitable one may improve this problem.

4. Replace sensor. If the sensor is damaged or the excitation current exceeds the rated value, the sensor needs to be replaced with a new one. When replacing, it is necessary to ensure that the specifications and performance of the new sensor meet the requirements of the flow meter, and that it is installed and debugged correctly.

5. Recalibrate. If there is a large deviation in the measurement data of the flow meter, zero flow calibration can be performed. During calibration, the rear valve needs to be closed to allow flow to fill the pipe to ensure measurement accuracy and stability.

In practical applications, appropriate solutions should be selected according to actual conditions, and care and maintenance should be paid attention to during use. Timely discovery and handling of problems can ensure the normal operation and measurement accuracy of the mass flow meter.