TE-5170V VFC TSP 25 Operations Manual
Use of Look-Up-Table to Determine Flow Rate
(NOTE: Individual Look-Up Tables will vary.)
1. Suppose the ambient conditions are:
Temperature: Ta = 20 oC
Barometric Pressure: Pa = 749.3 mm Hg (this must be station pressure which is not
corrected to sea level)
2. Assume system is allowed to warm up for stable operation.
3. Measure filter pressure differential, Pf. This reading is the set-up reading plus pick-up
reading divided by 2 for an average reading. This is taken with a differential
manometer with one side of the manometer connected to the stagnation tap on the
filter holder (or the Bulkhead Fitting) and the other side open to the atmosphere.
Filter must be in place during this measurement.
Assume that:
Set-up Reading (clean filter): Pf = 12.6 in H2O
Pick-up Reading (dirty filter): Pf = 16.0 in H2O
Pf = (12.6 + 16.0)/2 = 14.3 in H2O.
4. Convert Pf = to same units as barometric pressure.
Pf = 14.3 in H2O / 13.61 x 25.4 = 26.687729 mm Hg
Pf = 26.69 mm Hg
5. Calculate pressure ratio.
Po/Pa = 1 - (Pf/Pa)
NOTE: Pf and Pa MUST HAVE CONSISTENT UNITS
Po/Pa= 1 - (26.69 / 749.3)