For the selection of vortex flowmeters, if operation is stable without temperature and pressure compensation, how can such compensation be achieved?
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For the selection of vortex flowmeters for measuring gases, the requirement is a flow rate under standard conditions, as the operating conditions are stable. If a flowmeter without temperature and pressure compensation is to be used, how can accurate measurements be achieved? Is it necessary to perform compensation in the DCS?
If the operating conditions remain stable, it is possible to convert it to standard-condition flow rates; the gauge head can also be configured accordingly. However, the DCS is the most straightforward approach
It’s best for you to obtain the manufacturer’s flow calculation sheet; only with that can we develop a suitable solution for you. If the conditions specified in your process are not clear, things will get complicated. Therefore, the manufacturer’s calculation sheet should be taken as the standard. If the process specifies operating pressure and temperature, and the flow rate is given in Nm3/h, then as long as your actual operating conditions match those specified, no conversion is necessary – the measured value already represents standard conditions. This is because the manufacturer has already made the conversion during the calibration process, since standard-condition flow rates are required. You need to understand what thermal and pressure compensation is – it is required only when there is a difference between your actual operating conditions and the specified conditions. Of course, this is just compressed air; if it were steam, its flow rate would be the operating condition flow rate, so temperature and pressure compensation is necessary.
The unit of the conditioned flow rate in the process is Nm3/h. Under standard operating conditions, the process requirements specify that vortex flowmeters do not need temperature and pressure compensation. The manufacturer says it can provide flowmeters without such compensation (other manufacturers may not do this), but the measurements will be inaccurate, as the operating temperature is bound to change. Please advise on the exact procedure to follow: According to the process requirements, if vortex flowmeters are used without temperature and pressure compensation, can the flowmeters supplied by the manufacturer still give accurate readings?
The above is the compensation formula; temperature and pressure sensors are installed on the pipeline, the data is fed into the DCS, and a compensation formula can be created there
Take a look at my reply; I hope it can help you
The first one can convert the cube of the operating condition measurement into a standard cube. In vortex flowmeters, the meter head can be compensated by setting parameters such as the conversion temperature and pressure of the meter head, as well as the density of standard gases, to enable conversion of the meter head. The second method is to achieve conversion of temperature and pressure settings through the logical blocks within the DCS. The third is to achieve conversion through an integrator with temperature and pressure compensation. This is needed for measuring instruments
Floor 8 is very detailed; his answer is sufficient
Since it has been confirmed that the operating conditions are stable and a flow meter without temperature and pressure compensation was chosen, why is it still necessary to consider pressure stabilization compensation? Taking it a step further, if either the temperature or pressure is stable, it is sufficient to compensate only for the unstable one, rather than compensating for both temperature and pressure every time.