Electromagnetic Flow Meter After-Sales Case 2

Field problem

In the field, there are several flow meters with negative instantaneous flow; Although the pipeline is not empty, the transmitter shows zero.

Troubleshooting and analysis 

Upon receiving the feedback from customers, ARTang's technical team immediately understood the situation, checked and analyzed the faults:

1. The electromagnetic flowmeter is not displayed on the display, and the installation position of the electromagnetic flowmeter is close to the printing equipment. When the printing equipment is running, a large amount of steam is discharged, and the surrounding environment is humid. There is water mist on the surface of the instrument shell. In addition, the front and rear covers of the electromagnetic flowmeter are not tight, and the protection is not in place, which causes the circuit board to be damaged by moisture.

2. The electromagnetic flowmeter has negative flow. According to the field investigation, the length of the straight pipe section of the electromagnetic flowmeter does not meet the installation requirements (Front 5D, back 3D).

Solution

1. Replace the circuit board of electromagnetic flowmeter, coat the enclosure seal and tighten the cover.

2. Replace the installation position of electromagnetic flowmeter to meet the installation requirements of front and rear straight pipe sections.

Customer feedback

One month later, customer phone feedback showed that the electromagnetic flowmeter was still working normally.

Tips:

Why should we ensure a long enough straight pipe section when installing electromagnetic flowmeter?

The formula for measuring flow according to electromagnetic flowmeter is known: Q = A *V

A-cross-sectional area of pipeline, V-measured medium flow rate

When the direct pipe section is not enough, that is, when the measured medium flows through the damper (elbow and valve), the flow distribution will be distorted and vortex will occur. At this time, in any part of the pipeline, the flow rate is different and changes at any time. At this time, the measured medium flow cannot be calculated by mathematical formula. Therefore, when we install the electromagnetic flowmeter, the direct pipe section is enough to stabilize the flow and the output of the transmitter.