Due to its narrow measurement range and low signal strength, the micro flow mass flowmeter is much more sensitive to installation environment, process conditions, and maintenance strategies than conventional flowmeters. To ensure its long-term stable operation, a maintenance system needs to be constructed from four dimensions: installation, calibration, environmental control, and process adaptation. The following are specific implementation points:

1、 Zero stress installation: eliminating mechanical interference

The vibration amplitude of the measuring tube of the micro flowmeter is extremely small, and the installation stress will directly cause zero drift. It is necessary to ensure that the sensor flange is concentric with the process pipeline, and that the flange bolts are evenly stressed to avoid additional stress caused by pipeline misalignment or uneven bolt tightening. When installed vertically, the sensor measuring tube should be naturally emptied to prevent liquid residue; When installing horizontally, it is necessary to adjust the two measuring tubes to the same horizontal plane to avoid the influence of gravity asymmetry on vibration characteristics. For situations prone to vibration interference, independent support brackets should be installed at both ends of the sensor, and it is prohibited to use the sensor body as a pipeline support point.

2、 Dynamic zero calibration: addressing temperature drift and stress accumulation

Zero drift is the main source of error in small flow measurement. It is recommended to15-30Zero point calibration can be conducted on a daily basis, and important monitoring points can be shortened to once a week. Before calibration, it is necessary to ensure that there is no medium flow in the pipeline. First, close the downstream valve to empty the pipeline, and then close the upstream valve to create a static environment. By using the zero calibration function on the transmitter panel5-10Complete benchmark locking within minutes. If the error still exceeds the tolerance after calibration, it is necessary to check whether the installation stress of the sensor has been fully released, or whether there is hidden stress caused by pipeline thermal expansion.

3、 Precise control of process conditions: avoiding two-phase flow and parameter boundary crossing

Micro flow meters are extremely sensitive to the state of the medium, and it is necessary to ensure that the fluid is a single-phase flow. For easily vaporized media, a pressure gauge should be installed downstream of the flow meter to maintain the pressure at saturated vapor pressure by adjusting the back pressure valve1.5Multiple times or more, to prevent vaporization and the generation of bubbles. For media containing solid particles, it is necessary to install it upstream of the flowmeter100Above the target filter, regularly clean the filter screen to avoid particle blockage of the measuring tube or wear on the inner wall of the sensor. At the same time, it is necessary to strictly control the temperature of the medium within the rated range of the flowmeter to avoid deformation of the measuring tube caused by thermal expansion.

4、 Intelligent diagnosis and preventive maintenance

Utilize the self diagnostic function of the transmitter to monitor key parameters such as driving voltage and phase difference in real-time. If the driving voltage continues to rise, it may indicate scaling or leakage of the measuring tube; If the phase difference fluctuates beyond±2%It is necessary to check whether the medium contains gas or turbulence. Establish a flowmeter health record, record each calibration data, maintenance records, and process parameter changes, and predict fault trends through big data analysis. For example, if the zero drift increases linearly, it may indicate sensor aging; If the drift suddenly increases, it is necessary to check whether the installation environment has changed.

5、 Regular real flow verification: Verify measurement accuracy

According to the usage scenario, each6-12Conduct a real flow verification once a month. Using a medium similar to the actual working conditions (such as using actual liquid instead of water for calibration), at the rated flow rate of the flowmeter20%-100%Select within the scope5More than one measuring point, each measuring point runs stably30Record data in minutes. If the verification error exceeds the allowable range, the flow coefficient needs to be adjusted or the sensor needs to be replaced. For trade measurement scenarios, it is recommended to entrust someone withCNASQualified metrology institutions conduct calibration to ensure the legal validity of data.