The output signal of coke oven gas measured by vortex flowmeter is unstable

The vortex flowmeter is a volumetric flowmeter developed based on the Karman vortex principle to measure the volume flow rate, standard volume flow rate or mass flow rate of gas, steam or liquid. It is mainly used for flow measurement of industrial pipeline media fluids, such as gas, liquid, steam and other media.

The gases measured by the vortex flowmeter include: steam, oxygen, hydrogen, natural gas, nitrogen, air, gas, chlorine, carbon dioxide, coal gas, biogas, etc.

FAMIT Vortex Flowmeter

When the vortex flowmeter measures coke oven gas, the reasons why the output signal is unstable are as follows:

1. The vortex flowmeter is not suitable It is well known to users that it is installed in places with strong vibrations. However, in places where the magnetic field changes frequently, the vortex flow sensor will measure a signal output higher than the normal value. Practice has proved that when there is no gas flow at the site, when the vortex flow sensor is in a changing magnetic field, the vortex flow sensor will sense an error signal and output it at the moment when the magnetic field changes. When the change ends, the instrument is in a stable magnetic field. , the instrument will output a normal signal.

2. Because the coke oven gas has high temperature and high humidity when it leaves the factory, there will be moisture during the gas transportation process. The gas flow drives the moisture to reciprocate, thus forming a pulsating flow. When the vortex flow sensor is in this fluid state, the output data fluctuates between high and low, which cannot reflect the production status at all.

3. Because coke oven gas contains many impurities and is easy to crystallize, the impurities condense on the sensor head, causing measurement inaccuracy. When the temperature rises, the impurities volatilize, the sensitivity increases, and the signal is enhanced; on the contrary, it decreases. This results in data instability.

4. The wires are not pressed firmly during the instrument wiring process, resulting in intermittent signals during the transmission process.

5. The instrument grounding wire does not meet the specification requirements, so that the 50Hz interference in the strong current enters. When the normal signal is higher than 50Hz, a normal signal is output, otherwise an error signal will be output.

Solution:

1. During the instrument installation and connection process, every link should be ensured to be accurate, including site inspection before installation, instrument wiring during installation, System grounding wire, etc., to ensure that real data is detected and output accurately.

2. For the running metering system, the "dual-track metering, comparison and confirmation" method and the "substitution method" can be used to confirm and eliminate the faults of the metering instruments in operation.

3. Clean the instrument as a whole regularly. If necessary, purge the sensing head of the instrument to prevent impurities from condensing on the sensing head. In the cold season, adding heating devices to the metering straight pipe section and the meter section will also help alleviate the condensation of impurities at the metering meter.

FAMIT Vortex Flowmeter

4. Drain the pipeline regularly, especially the water in front of the straight pipe section. According to the specific situation, set up a dedicated person to drain regularly to reduce the meter as much as possible.Measure the moisture in the pipe section and eliminate the pulsation in the fluid to the maximum extent.

5. Strengthen the management of metering system data, set up a scheduled printing function, and analyze the operation of the instrument based on the printing data and production status.