drbitboy
Lifetime Supporting Member
1. I found several references that documented that orifice plates installed backwards always read low on the order of 10-35% from actual flow rate.
Heh.
I once saw an orifice plate so eroded/corroded on both sides there where radial gullies on both sides, and if you held it up to the light you could see pinholes where the gullies had met.
Flow is notoriously difficult to measure, anyone who believes an industrial (i.e. outside of a precision lab or test setup) measurement is better than 10-50% is making a bad judgement.
My dad and his colleagues at GE use to measure large steam turbine performance to better than a quarter percent accuracy; the key was that they did not need the flow nozzle measurement to get there, but instead inferred total flow from the process.