Teledyne 306WA - Analog trace oxygen analyzer - Manual (Page 44)

A-6
Appendix Appendix Appendix Appendix Appendix Model 306W Model 306W Model 306W Model 306W Model 306WA A A A A
TELEDYNE ELECTRONIC TECHNOLOGIES
Analytical Instruments
To determine the corrected vent flow rate it will be necessary to know
the ambient temperature (in °K), the ambient pressure (in mm Hg) and the
vapor pressure of water at ambient temperature.
Ambient temperature can be measured in °Centigrade or °F and con-
verted to °K.
Degrees C = 5 (°F -32)
9
Degrees K = °C + 273
Ambient pressure can be measured with an accurate barometer.
P(mm Hg) = P(in Hg) x 760
30.00
or by knowing the altitude
P(mm-Hg) = 760 - (2.50 per 100 ft. of altitude)*
The vapor pressure of water at ambient temperature can be obtained
from Table 1 on page A.8.
To determine the corrected flow (F
corrected
), substitute the ambient tem-
perature, pressure and vapor pressure of water in the following formula:
F
corrected
=150 cc/min x T X 760 mm-Hg X (P+Pwater)
294 °K** P P
Where:
T = ambient temperature (in °K)
P = ambient pressure (in mm Hg)
P
water
= vapor pressure of water at ambient temp. (in mm Hg)
By way of example, suppose that the target’s position on the flow tube
is in question and it has been determined that the ambient temperature is 77
°F and the altitude where the instrument is being used is 5000 ft. above sea
level.
Ambient Temp: °K = 5(77–32) + 273 = 298 °K
9
*
This approximation is within ±0.5% of the ICAO Standard Atmo-
sphere over the range 0-7500 ft. above sea level. Ref: “Fluid Mechanics for
Engineering Technology” by Irving Granet, Prentice Hall, pp 83–84.
**
Reference ambient temperature : 294 °K (21 °C) was the ambient
temperature used in the Faradaic calculations.