- Oct 31, 2017 -
1. Ensure full installation
Electromagnetic flowmeter measuring tube must be full tube state, can not appear non-full tube state. If the pipe is not full pipe or the outlet is vented, the sensor should be mounted on a siphon. Avoid installation in the downstream pipe upstream, to avoid the highest point in the pipeline, easy to gather bubbles.
2 Horizontal and vertical installation
The sensors can be installed horizontally and vertically, but should ensure that the effects of sediment and bubbles on the measuring electrode are avoided and that the axial retention of the electrodes is good. When installed on a horizontal pipe, the two measuring electrodes should not be just above and just below the pipe. Vertical installation, the fluid should flow from bottom to top.
The inlet straight pipe pipe should be greater than 5D, the outlet straight pipe should be larger than 2D. There are specific installation requirements should be based on electromagnetic flowmeter instructions for installation. Plug-in inlet straight pipe should be ≥ 20 D, export straight pipe ≥ 7D (D for the sensor nominal diameter).
3 exit for the installation when venting
When the outlet is empty, the sensor should not be installed in the pipeline vent, should be installed at a lower place. When the sensor is installed in the lower part of the pipeline, it is necessary to ensure that the sensor is filled with liquid, can not appear empty tube state.
4 series installation and parallel installation
If there are several sensors that need to be connected in series on the same pipe, the distance between each sensor should be at least two sensors. If two or more sensors are installed in parallel with each other, the distance of the sensor must be greater than 1 m.
5 installation between the elbow, the valve and the pump
In order to ensure the stability of the measurement, should be set in front and rear of the sensor straight pipe, the length given by the following figure. If you can not do so, you should use a current regulator or reduce the cross-sectional area of the measurement point.
6 installation plus bypass pipe
Pipes in the installation of the flowmeter should be able to cut off the pipeline medium media to facilitate routine maintenance and maintenance. The process does not allow traffic to be interrupted. You can add a bypass pipe to the pipe where the flowmeter is installed.
7 Install in the calibration direction
When the flowmeter sensor has a clear flow indication, it should be installed in the calibration direction.
8 inlet, cable and threading
Flow meter inlet, cable and threading pipe should be bent down, and at the lowest opening, so as not to water, resulting in short circuit.
9 welding flange
Flow meter installation, the flange should be welded first, and then install the flow meter, can not directly with the flow meter sensor directly welded flange, so as not to burn the lining will burn.
10 The distance between the converter and the sensor
The signal line between the converter and the sensor can not be greater than 50m, and the signal line must be worn with a galvanized tube.
11 sensor grounding measures
The sensor generates a very small flow signal and is only a few millivolts at full scale, so the sensor should be grounded well. Electromagnetic flowmeter grounding requirements in two ways:
From the working principle of the electromagnetic flowmeter and the flow of the induced signal current, the ground of the sensor and the converter must be at the same potential as the measured medium.
Ground to the ground for the zero potential, reduce external interference.
Under normal circumstances, the process of pipe are metal pipe, itself is grounded, this requirement is easy to meet. However, in the case of external electromagnetic interference, electromagnetic flowmeter should be set up grounding device, the ground wire with a cross-section greater than 5mm2 multi-strand copper wire, the sensor ground wire must not be connected to the motor or other equipment on the public ground, To avoid leakage current. The grounding resistance should be less than 10Ω.
The sensor is installed on the metal pipe (the metal pipe wall is not insulated coating), according to the figure to ground.
The sensor is mounted on a plastic pipe or on an insulated lining. The sensor should be fitted with a grounding ring, or a ground flange, or a short tube with a ground electrode.
So that the tube flow of the measured medium and the ground short circuit, with zero potential, otherwise, the electromagnetic flowmeter does not work properly.