The gas vortex flowmeter may encounter some problems when measuring coke oven gas. Now let's analyze the causes and solutions of these problems.
The reasons for the malfunction of the on-site measurement system can be regarded as two major reasons, one is caused by the flow meter or its associated equipment; The second reason is that, in addition to reasons related to the flow meter, even if the flow meter is normal, it is difficult to identify the reasons for malfunctions caused by environmental or system factors. In addition to requiring technical personnel to be familiar with the performance of the product, it is also necessary to have extensive knowledge and rich on-site experience for analysis, deliberation, and multi-party testing in order to determine. Minor malfunctions or unexpected events can cause it. Faults other than flow meters generally manifest as unstable output signals. Based on practical experience, the reasons for the unstable output signal of the vortex flowmeter when measuring coke oven gas are:
1. It is widely known that gas vortex flow meters are not suitable for installation in strong vibration environments. However, in situations where the magnetic field frequently changes, vortex flow sensors can also be interfered with and measure signals higher than the general value. Practice has proven that in a field without gas flow, when the vortex flow sensor is in a changing magnetic field, it will sense an erroneous signal output at the moment of magnetic field change. When the change ends and the instrument is in a stable magnetic field, the instrument will output a normal signal.
2. Coke oven gas has a high temperature and humidity when it leaves the factory, so there will be moisture present during the gas transportation process. Gas flow drives water to fluctuate back and forth, thus forming pulsating flow. When the vortex flow sensor is in this fluid state, the output data fluctuates greatly and cannot reflect the production status at all.
3. During the instrument wiring process, the pressure wire is not solid, resulting in intermittent signals during transmission.
4. Due to the high impurities in coke oven gas, it is easy to crystallize and condense at the sensing head, resulting in inaccurate measurement of the flow meter. When the temperature rises, impurities evaporate, sensitivity increases, and signal enhancement occurs; Conversely, it decreases; This leads to data instability.
5. The grounding wire of the instrument does not meet the specification requirements, which causes 50Hz interference in the strong current to enter. When the normal signal is higher than 50Hz, the output signal is normal, otherwise it will output an incorrect signal.
terms of settlement:
1. During the installation and connection of flow meters, every step should be ensured to be error free, including on-site inspection before installation, instrument wiring and system grounding during installation, etc., to ensure the detection of real data and accurate output.
2. Adding heat tracing devices in the metering straight pipe section and instrument section during cold seasons is also beneficial in alleviating the condensation of impurities at the gas vortex flowmeter.
Regularly clean the gas vortex flowmeter as a whole, and if necessary, blow the sensing head of the instrument to avoid the condensation of impurities at the sensing head.
4. For the operational metering system, the methods of "dual track metering, comparative confirmation" and "substitution method" can be used to confirm and eliminate faults in the operational metering instruments.