Electromagnetic flowmeter instrument installation

Electromagnetic flowmeter instrument installation

Electromagnetic flowmeter is simply composed of a flow sensor transmitter. The installation requirement of the electromagnetic flowmeter is that it must be installed at the low point of the pipeline or the vertical section of the pipeline, but it must be when the pipe is full. The requirement for the straight pipe section is 5D in front and 3D in the back, so as to ensure the efficiency of the electromagnetic flowmeter. usage and accuracy requirements.

The measurement principle of the electromagnetic flowmeter does not depend on the flow characteristics. If there is certain turbulence and vortex in the pipeline in the non-measurement area (such as: elbow, tangential flow restriction or a half-open upstream stop valve) is irrelevant to the measurement. 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< /p>

2. Use a flow stabilizer

3. Reduce the cross-section of the measuring point.

1． Requirements for the external environment

1. The flowmeter should avoid being installed in places where the temperature changes greatly or is subject to high-temperature radiation from the equipment. If it must be installed, heat insulation and ventilation measures must be taken.

2． The flow meter is installed indoors. If it must be installed outdoors, it should be protected from rainwater, flooding and sun exposure. Moisture-proof and sun-proof measures must be taken.

3． The flowmeter should be avoided from being installed in an environment containing corrosive gases. When it must be installed, ventilation measures must be taken.

4． In order to facilitate installation, maintenance and upkeep, there must be ample installation space around the flow meter.

5． The installation site of the flow meter should avoid magnetic fields and strong vibration sources. If the pipe vibration is large, there should be supports to fix the pipe on both sides of the flow meter.

2. Pipeline electromagnetic flowmeter

1. Requirements for straight sections

In order to improve the influence of eddy currents and flow field distortion, the length of the straight pipe sections before and after the flowmeter is installed has certain requirements, otherwise the measurement accuracy will be affected (a rectifier can also be installed, try to avoid Install close to the regulating valve and half-open valve).

2． Requirements for process pipes

The flow meter has certain requirements for 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 meet: 0.98DN≤D≤1.05DN (where DN: sensor inner diameter, D: process pipe inner diameter)

b. The process tube and sensor must be concentric, and the coaxial deviation should not be greater than 0.05DN

2.3. Requirements for bypass pipes

In order to facilitate the maintenance of the flow meter, a bypass pipe must be installed for the flow meter. In addition, for heavily polluted fluids and where the flow meter needs to be cleaned but the fluid cannot be stopped, a bypass pipe must be installed.

a. Convenient maintenance of flow meter

b． Must be installed for heavily polluted fluid

c. The fluid cannot be stopped but the flowmeter needs to be cleaned

Electromagnetic flowmeter instrument installation 3. Installation requirements for plug-in electromagnetic flowmeter

1. Requirements for straight pipe sections

Inlet/outlet straight pipe sections: the entrance should be ≥10×DN; the outlet should be ≥5×DN

2. Requirements for grounding points

In order to make the instrument work reliably, improve measurement accuracy, and not be interfered by external parasitic potentials/sensors should be well grounded, with a grounding resistance of less than 10. (If the metal pipe is well grounded, there is no need to Dedicated grounding device) 3.3 The installation location requirements are as shown in the figure

Insert the electromagnetic flowmeter according to the on-site pipeline conditions. The flowmeter without ball valve should be installed on the pipeline without overturning. Installation (that is, without pressure installation, you can choose a flowmeter without a ball valve), open a hole with a diameter of 50 on the pipeline, and prepare to weld the connecting welded pipe to the opening of the pipeline; for 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 must be selected; the diameter of the opening on the pipeline is 50, and the connecting welded pipe is prepared to be welded to the opening of the pipeline.