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The working principle of the mass flow meter and the matters to be avoided during the use

The mass flow meter produces a force on the pipe wall as it flows through the rotating pipe. It was discovered by Coriolis when the turbine was studied in 1832, referred to as Coriolis force. The mass flowmeter is based on Coriolis force. There are two parallel T-shaped vibration tubes inside the sensor. The sensor is equipped with a drive coil in the middle. The excitation coil is installed at both ends. The excitation voltage provided by the transmitter is added to the drive. When the coil is on, the vibrating tube vibrates in the reciprocating cycle mass flow period, and the fluid medium in the industrial process flows through the vibrating tube of the sensor, and a Coriolis force effect is generated on the vibrating tube, so that the two vibrating tubes are torsionally vibrated and installed in the vibrating The pick-up coils at both ends of the tube will produce two sets of signals with different phases, which are proportional to the mass flow rate of the fluid flowing through the sensor. The computer calculates the mass flow through the vibrating tube. When different media flows through the sensor The main vibration frequency of the vibration tube is different, and the medium density is calculated accordingly. The platinum resistance installed on the sensor vibration tube can indirectly measure the temperature of the medium.

Therefore, we should avoid the following events during the measurement process:

1. Rigid and unstressed support of the sensor

2. Avoid installing the sensor at the highest position of the pipe, because the bubbles will collect and stay, causing measurement errors in the test system;

3. If the long downstream pipeline (usually not more than 3M) cannot be avoided, an additional flow valve should be installed;

4. The distance from the pump should be at least 4 times longer than the length of the sensor itself (the distance between the two flanges). If the pump causes excessive vibration, it must be isolated by a coiled tube or a connecting tube.

5. Additional devices such as regulating valve and inspection window should be installed at least 1X "L" away from the sensor (L is the distance between the sensor mounting flange)

6, the bracket can not be installed on the flange or the outer casing, generally the distance from the flange is 20~200mm;

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