The electromagnetic flowmeter is simply composed of a flow sensor transmitter. The installation requirements of the electromagnetic flowmeter must be installed at the lowest point of the pipeline or the vertical section of the pipeline, but it must be in the case of full pipelines. usage and accuracy requirements.
The measurement principle of the electromagnetic flowmeter does not depend on the characteristics of the flow. If there is a certain amount of turbulence and eddy in the pipeline in the non-measurement area (such as elbows, tangential flow restrictors or a half-open stop valve upstream), it will be the same as the measurement. It doesn't matter. If there is a steady eddy current in the measurement area, it will affect the stability and accuracy of the measurement. At this time, some measures should be taken to stabilize the flow velocity distribution:
1. Increase the length of the front and rear straight pipe sections
2. Use a flow stabilizer
3. Reduce the cross section of the measuring point.
1. Requirements for the external environment
1.1. The flowmeter should be avoided to be installed in places with large temperature changes or high temperature radiation of the equipment. If it must be installed, measures of heat insulation and ventilation must be taken.
1.2. The flowmeter is best installed indoors. If it must be installed outdoors, it should avoid rainwater, flooding and sun exposure. Moisture-proof and sun-proof measures must be taken.
1.3. The flowmeter should be avoided to be installed in an environment containing corrosive gas, and ventilation measures must be taken when it must be installed.
1.4. For the convenience of installation, maintenance and maintenance, there should be ample installation space around the flowmeter.
1.5. The installation site of the flowmeter should avoid magnetic fields and strong vibration sources. If the pipeline vibrates greatly, there should be supports for fixing the pipeline on both sides of the flowmeter.
1. 2. Pipeline electromagnetic flowmeter
2.1. Requirements for straight sections
In order to improve the influence of eddy current and flow field distortion, there are certain requirements for the length of the straight pipe section before and after the flowmeter is installed, otherwise it will affect the measurement accuracy (the rectifier can also be installed, try to avoid installing it close to the regulating valve and half-open valve).
2.2. Requirements for process pipes
The flowmeter has certain requirements on the upstream and downstream process pipes of the installation point, otherwise the measurement accuracy will be affected.
a. The inner diameter of the upstream and downstream process pipes is the same as the inner diameter of the sensor, and should satisfy: 0.98DN≤D≤1.05DN (where DN: the inner diameter of the sensor, D: the inner diameter of the process pipe)
b. The process tube and the sensor must be concentric, and the coaxial deviation should not be greater than 0.05DN
2.3. Bypass requirements
In order to facilitate the maintenance of the flowmeter, it is better to install a bypass pipe for the flowmeter. In addition, for the heavily polluted fluid and the flowmeter to be cleaned and the fluid cannot be stopped, the bypass pipe must be installed.
a. Easy flow meter maintenance
b. Must be installed for heavily contaminated fluids
c. Fluid does not stop and flowmeter needs cleaning
3. Insertion electromagnetic flowmeter installation requirements
3.1. Requirements for straight pipe sections
Inlet/outlet straight pipe section: the inlet should be ≥10×DN; the outlet should be ≥5×DN
3.2. Docking location requirements
In order to make the instrument work reliably and improve the measurement accuracy, it will not be disturbed by the external parasitic potential / the sensor should be well grounded, and the grounding resistance should be less than 10. (If the metal pipe is well grounded, no special grounding device is required)
3.3 Requirements for installation location
Insert the electromagnetic flowmeter according to the situation of the on-site pipeline. The flowmeter without the ball valve should be installed on the pipeline without overwhelm (that is, the flowmeter without the ball valve can be selected for the installation without pressure), and the pipeline should be opened. The diameter is 50, and the connecting welded pipe is ready to be welded on the opening of the pipeline; for the occasions that require continuous flow loading and unloading or do not allow the medium to overflow, a ball valve must be installed, that is, a plug-in electromagnetic flowmeter with a ball valve structure is selected; open holes in the pipeline The diameter is 50, and the connecting welded pipe is ready to be welded on the opening of the pipe.
Insertion electromagnetic flowmeter selection
Measuring range: Recommended range: 0.5m/s～10m/s continuously adjustable. Maximum use range: 0.2m/s～15m/s continuously adjustable
Signal output: 1. The switch value can be set to: pulse output (up to 1000HZ); high/low flow alarm; empty pipe alarm; flow direction indication;
Fault alarm; 2. Current output: 4-20mA output
Configuration method: 1. On-site configuration through three manual keys. 2. On-site configuration through remote control. 3. On-site configuration is carried out through the hand-held communicator.
