How to modify it to mass flow rate
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One of the flow measurement instruments in our factory – the drawings specify that it should be a mass flow meter, but what is installed on site is a vortex flow meter. Can it be changed to a mass flow meter in the DCS system? If possible, how should it be modified?
The volume flow rate measured by the vortex street sensor; if you have the density, you can convert it into mass flow rate
Adding to what was said above: if the density changes significantly with temperature, an additional temperature transmitter is needed for temperature compensation
Additionally, if it is a gas, temperature and pressure compensation is necessary, as the density of gases varies under different pressures and temperatures! For liquids, only the density is needed to determine the values (provided the requirements are not stringent!)
What was said upstairs is correct – it depends on the medium and the specific operating conditions. The key thing is to know the density. If it’s inconvenient or costly to apply various temperature or pressure compensations, or if the diameter of the pipeline is large, then for more accurate measurements, I think it’s possible to use a bypass with a smaller diameter, along with a mass flow meter of smaller size, in order to determine the density accurately. The original poster should decide based on the specific circumstances~
The instrument used for measuring flow rate is a vortex flow meter; temperature compensation is applied for liquids, while pressure and temperature compensation are used for gases. The value can be converted into mass flow rate in the DCS system.
Reply to 1# longyu123a: Mass flow rate = Volume flow rate * Density
I agree with what was said on floor 5, but installing a smaller mass flow meter also comes at a high cost!
First of all, to determine the mass flow rate from the volume flow rate, it is necessary to know the density of the fluid. Under industrial and operational conditions, changes in pressure and temperature can affect the density of gases; therefore, when measuring gases, it is first necessary to convert the value to the flow rate under standard conditions through temperature and pressure compensation, and then multiply by the density at standard conditions. For liquid measurements, there is no need for such adjustments – simply multiplying the volume flow rate by the density is sufficient. Additionally, vortex flow meters are velocity-type flow meters, and they measure volume flow rate by multiplying the velocity by the pipe diameter
It can be changed, but it is necessary to know the density of the medium under operation. For E+H vortex flowmeters, this can be adjusted using the combination keys on the menu bar; first, the unit must be changed to kg/h or kg/s, and then menu settings should be made. Once the density has been set, the mass flow rate will be calculated as: mass flow rate = volume flow rate * density!
In locations with low requirements, the mass can be obtained indirectly using the volume * density method, and this can be modified in the settings. After all, the specific mass of vortex streets is much cheaper.