The Analysis of Principle and Running Fault of Gas Flow Meter

1. Principle of gas flow meter

1.1 structure principle

A gas flow meter is a volume meter measuring the flow of gas through the pipe. It consists mainly of the shell, the conjugate rotor and the deceleration counting device. Its metering process and working principle are shown in figure 1 (the figure shows one quarter cycle). A pair of conjugate rotors installed in the metering chamber and the two rotors can withstand the rotation torque alternately under the pressure difference of the outlet pressure of the circulating gas (P in > P out), . When rotor rolls 1 cycle, it outputs four times meterage of effective volume of the gas flow. By coupling magnetic seal device and retarding mechanism, the revolutions of the rotor passed to integrating instruction counter, which shows the output of the gas flow. By changing the value for these wheels, the flow meter of the error adjusts. The conjugate ball bearings are equipped with lubricating devices.

1.2 application scope

Gas flow meter has a wider range of work pressure and wide flow rate range. It also has high precision and reliable use and other features. And it has strong adaptability circulation medium, so it can be widely used as air flow measurement such as in natural gas, the artificial coal gas and inert gas. Domestic and foreign city gas, oilfield chemical, scientific research and other departments adopt the flow measurement device, which plays a significant role in the modernization management, economic accounting and energy saving of enterprises. Flow meter is mainly composed of two main parts, the measuring part and integrating part (figure 2 is the meter structure schematic drawing). It can display the accumulated flow on the spot. According to the need, it can be configured to send news agencies, to make the flow measurement over a long distance.

2 Analysis of principle and running fault of gas flow meter

After the site pipeline is checked, the compressed air whose pressure is about 5.5~6kg/cm2 enters the plant. The compressed air is supplied by the bypass pipe, but the main pipe of the gas flow meter loop is not applied. In the front of the gas meter is equipped with filtering valve for gas filtration. But when the gas flow meter was being installed at the beginning, because of a lack of technical data and the correct valve installation instructions, the gas meter was inverted, and the integrating header was inverted. Magnetic coupling which is synchronized with box body then became a storage place; The gear and bearing were not properly maintained, so the gear rusting was serious, and the bearing seized and the rotor cannot rotate. The filter valve was corroded, and the filter adhered with the impurities. And the flow meter was clogged with slag, so the air flow decreased and caused the gas supply failure.

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