Storage and transportation metering
Thread Content
In our measurement system, we have level measurement and mass flow meter measurement; however, for discharging and receiving materials, mass flow meters are used for measurement, while levels are used for verification. But in the final measurement, a significant difference is found – there are several tons of difference each time. Dear experts, how should we measure this in order to make improvements? Thank you!
It’s a long story – has the mass flow meter been calibrated? What is the accuracy of the level gauge? What kind of level gauge is it? Has the level gauge been calibrated? How is it calibrated? Is temperature compensation done? How is density measured? Is the tank capacity table correct? Is the volume calculation correct? Is the mass calculation correct? These are all the places where errors can occur. In short, there is definitely some deviation when converting mass flow meters and level gauges to mass. If there is no such deviation, something is wrong; it’s only possible under extremely strict technical conditions (though this is very rare in China).
So all the problems lie in that damned quality measurement; if we followed foreign practices and used volume-based delivery, there would be far fewer problems, haha.
When there is a discrepancy between the mass flow meter and the level gauge, we generally trust the level gauge. The reason is simple: the volume of the container is known beforehand, and it’s possible to check the level gauge to see if there are any blockages; whereas it’s not so easy to assess the mass flow meter. Moreover, in most cases, the mass flow meter is more likely to develop problems.
The measurement error of mass flow meters is too large; a volume flow meter should be used to measure volume, and the mass can then be calculated by determining the density.
Both parties should standardize the gauge model, calibration dimensions, and measurement units. Storage and transportation generally involve tank inspection
It mainly depends on the method used by the parties involved in the handover, but regardless of the method, if there are repeated instances of significant discrepancies between the readings provided by the flow meter and those from the tank gauge, it is necessary to send the flow meter for inspection and calibration, so as to determine what the exact problem is!
Whenever there is an error or discrepancy in the flow meter, it must be re-evaluated. Generally, we use flow meters as a means for comparison, while manual measurement and weighing are the primary methods.
It is impossible to have no errors in measurement transfers; using two different measurement methods results in even greater errors. The situation described on the second floor is indeed a reality. Therefore, one unit should use one single method for measurement.
In such cases, it is standard practice to rely on manual measurement with a gauge; level gauges and mass flow meters can exhibit significant errors. It is necessary to regularly compare the readings obtained from manual measurements with those from the level gauges and flow meters on multiple occasions, in order to identify any issues and to calibrate or verify these instruments.
Promote more scientific and convenient volume measurement!
Strongly agree, but it’s impossible in China in the foreseeable future, haha.
Personally, I think the principle generally adopted in design is to follow the principles of similar flowmeters； Of course, the possibility of using a volumetric flow meter in this case is quite high ； This is mainly because volumetric flowmeters can be calibrated online, while mass flowmeters generally need to be sent for calibration!
Thank you all for your help. I think I should check the mass flow meter to see if there are any issues.
The accuracy of mass flow meters is higher than that of level gauges; level gauges are not as accurate as manual measurements. We use the data from level gauges only as a reference, and not as data for handover purposes
The accuracy of static measurement is usually better than that of dynamic measurement, and the accuracy of measurement in shore tanks is better than that in ship holds. Manual measurement is required for the handover of quantities.
What’s wrong with quality measurement? Admiring foreign things and subservience to foreigners:@
Static measurement accuracy is usually better than dynamic measurement accuracy, right? Not necessarily