Installation method and skill of electromagnetic flowmeter

Nov 13 , 2019

Electromagnetic flow meter is a flowmeter which measures the flow according to Faraday's electromagnetic induction law. The advantages of electromagnetic flowmeter are small pressure loss and large range of measurable flow. The ratio of the maximum flow rate to the minimum flow rate is generally more than 20:1, which is applicable to a wide range of industrial pipe diameters, with a maximum of 3M. The output signal is linear with the measured flow rate, with high accuracy.

 Installation method and skill of electromagnetic flowmeter

Installation method and skill of flow meter:

I. sensor installation

1) when measuring the mixed phase fluid, select the place that will not cause phase separation; when measuring the two-component liquid, avoid installing it in the downstream where the mixing is not uniform; when measuring the chemical reaction pipeline, install it in the downstream of the section where the reaction is fully completed;

2) try to avoid negative pressure in the measuring pipe;

3) avoid nearby large motors, large transformers, etc., to avoid electromagnetic interference;

4) try to avoid high concentration of corrosive gas in the surrounding environment;

5) avoid direct sunlight as much as possible;


II. Requirements for installation of straight pipe section

First of all, it should be noted that the sensor itself cannot be used as the load support point, it cannot support the adjacent working pipeline, and it should be clamped with the pipeline bearing. In order to obtain the normal measurement accuracy, there must be a certain length of straight pipe upstream of the electromagnetic flow sensor, but its length is lower than most other flow instruments. However, it is necessary to prevent the butterfly valve from extending into the sensor measuring pipe. The length of the upstream and downstream straight pipe sections proposed by each standard or verification regulation is also inconsistent, and the requirements are higher than that of the general requirements as shown in the figure below. This is because to ensure the accuracy of the current 0.5 level instrument requirements.

III. installation position and flow direction

The axis of the measuring electrode must be approximately horizontal;

The measuring pipe must be completely filled with liquid;

At least 5xd (D is the inner diameter of the flowmeter) length straight pipe section shall be provided in front of the flowmeter, and at least 3XD (D is the inner diameter of the flowmeter) length straight pipe section shall be provided in the back;

In order to facilitate installation and disassembly, a pipe expansion joint can be installed behind the flowmeter. The flow direction of the fluid is consistent with the arrow direction of the flowmeter;

If there is vacuum in the pipeline, the lining of the flowmeter will be damaged. Special attention shall be paid;

There should be no strong electromagnetic field near the flowmeter;

There shall be sufficient space near the flowmeter for installation and maintenance;

If there is vibration in the measuring pipeline, there shall be fixed supports on both sides of the flowmeter;