Allowable pressure loss in the instrument flowmeter condition table
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Among the conditions specified for the flow meter used in the instrument, there is one that allows for a certain pressure loss. I’m unsure as to how this value is determined; I asked others and was told that it is generally estimated based on previous projects. I wonder whether this value is simply estimated or if there is a specific calculation method. If it is estimated, what would be a reasonable range for that estimate?
Different types of flowmeters have varying pressure drops. Typically, the orifice plate is at 0.3 bar, the mass flow meter at 1 bar, and the vortex flow meter at 0.5 bar
Of course, it is calculated based on the system requirements.
Could you explain in detail how it’s calculated?
The starting pressure, the ending pressure, the pressure drop in the pipes and equipment, as well as the head of the pump selected – by performing a comprehensive calculation, it can be determined whether the power available is sufficient to overcome the resistance. If the values are very close to each other, it is necessary to set an upper limit for the pressure drop across the flow meter.
How is the head of that pump calculated?
When determining the pump head, it is reasonable to use a pressure drop of 15–3% of the pressure drop in the pipeline system. If the pump head seems to be constrained as part of a retrofitting process, then use 15% of the pipeline’s pressure drop; generally, around 25% is a suitable value
I don’t think it’s necessary to mention this issue of allowable pressure loss – flow meters are already finished products, and if you buy them, you have to accept the pressure loss associated with them. Moreover, the pressure loss differences between different manufacturers are probably not that significant. . . .