Installation requirements for vortex flowmeters and electromagnetic flowmeters
Comparison of Installation Requirements for Vortex Flowmeters and Electromagnetic Flowmeters
Both installations have core requirements that revolve around maintaining a stable flow field, full pipe operation, and avoiding interference. However, due to differences in principles, the specific requirements are significantly different:
I. Installation Requirements for Vortex Flowmeters
1. Requirements for the straight pipe section
The standard requires a straight pipe section of 10D in the front and 5D at the back (D represents the pipe diameter). If there are obstructive components such as elbows or valves upstream, a flow straightener should be installed, which can be shortened to 5D in the front and 2D at the back. Installation is strictly prohibited near the pump outlet (to avoid fluid pulsation).
2. Installation Position
Horizontal installation: The axis of the vortex generator must be parallel to the horizontal plane to prevent impurities from depositing on the surface of the generator.
Vertical installation: The fluid should flow from bottom to top, ensuring full pipe and preventing bubble retention.
When measuring steam, it should be installed horizontally, with the pressure tapping point located in the horizontal direction of the pipeline, which is convenient for installing a condenser tank.
3. Avoidance of Environmental Interference
Keep away from strong vibration sources (such as motors and compressors), as vibration can cause distortion of the frequency signal; maintain a distance of ≥ 0.5 meters from the frequency converter and power cables, and install shielding sleeves if necessary.
4. Requirements for fluid state
The operation must be continuous. The gas content of the medium should be less than 5%, and the solid content should be less than 1%. This is to prevent the generation of vortices in the two-phase flow.
5. Other Requirements
The installation of the flange should be coaxial with the pipeline, and the sealing gasket must not protrude into the pipeline; for high-temperature conditions, a high-temperature-resistant flange should be selected to prevent the sealing from failing.
II. Installation Requirements for Electromagnetic Flowmeters
1. Requirements for the straight pipe section
It should be lower than vortex flow meters. For conventional types, a straight pipe section of 5D in the front and 3D at the back is required. If there are severe turbulence-inducing components upstream (such as three-way valves or ball valves), the length should be extended to 10D in the front and 5D at the back.
2. Installation Position
Horizontal installation: The electrodes should be placed horizontally or vertically in the pipeline. Horizontal installation can prevent bubbles from adhering to the electrodes, while vertical installation can reduce the deposition of impurities.
Vertical installation: The fluid flows from bottom to top. This is the optimal installation method, which can completely solve the problems of full pipe and bubbles.
When measuring corrosive media, it is necessary to ensure that the inner lining is compatible with the medium and avoid scratching the inner lining during installation.
3. Grounding and Interference Avoidance
It is necessary to perform equipotential grounding, with the grounding resistance being no more than 4Ω. The sensors, pipelines, and transmitters should be connected to the same grounding body; keep away from strong electromagnetic interference sources (such as frequency converters and high-frequency equipment), and the signal cables should be laid separately in shielded conduits.
4. Requirements for Fluid State
Strictly operate in full pipeline mode. Air leakage will cause the measured value to drift. It is possible to measure slurry with a solid content of ≤ 10% (such as mud and ore slurry), but large particles must be avoided to prevent wear on the inner lining.
5. Other Requirements
During installation, it is strictly prohibited to strike the sensor housing to prevent electrode damage; for negative pressure conditions, a model resistant to negative pressure should be selected to avoid the inner liner being deformed.
