Working principle：
When the fluid flows through the orifice plate of the orifice plate flow meter device, the cross-sectional area decreases, the velocity increases, and the corresponding pressure decreases, and the degree of reduction is proportional to the fluid velocity of the flow state. Therefore, the flow rate can be calculated by detecting the pressure difference, and then the flow rate can be calculated.
Operating condition:
Outlet flow of lean methanol water cooler, measure the flow of injected methanol, medium: lean methanol, temperature: 42℃, pressure 4.31Mpa, this table is only for display, without linkage.
Fault phenomenon:
Indicated fluctuation
Fault analysis:
1. Whether the pressure guide pipe is blocked;
2. Whether the three valve groups are blocked;
3. Transmitter itself;
4. Flexible leakage point;
5. Transmitter zero drift;
6. The transmitter range is not set correctly;
7. Process issues.
Treatment method:
1. First check the live joint of the pressure guide pipe and the sealing position of the three valve groups and no leakage is found.
2. Close the positive and negative pressure root valves and open the transmitter blowdown plug for blowdown. At this time, it is not found that the medium is not flowing smoothly, and the possibility of blocking the pressure guide tube and the three valve groups is excluded.
3. Open the balance valve of the three valve groups of the flow meter and remove the blowdown screw plug. At this time, the check finds that the central control still has the flow indication when the meter head indicates zero. At this time, a multimeter is used in series to measure the output of the transmitter to 8.01mA, and the reason is judged to be the transmitter itself.
4. At the same time, it can be judged that the measurement capsule and converter display are normal through the on-site scheduling check process.
5. Remove the differential pressure transmitter and disassemble it. It is found that the terminal block is seriously corroded.
6. Clean up the corrosive substances in the differential pressure transmitter, check whether the circuit board components are damaged, replace the terminal block of the differential pressure transmitter, and re-weld the terminal block with a wire.
7. Assemble the differential pressure transmitter, and check its zero output normal through the power supply.
8. Differential pressure transmitter back assembly.
9. Before installation, check whether there is debris in the pipe to prevent debris from blocking or damaging the standard orifice plate.
Thank You
