(i) When calibrating thermometer set 7910479, select TI model 62C as
first item to be calibrated.
(j) Adjust temperature bath (A7) to approximately -30,C.
(k) Lower resistance thermometer into temperature bath along with TI
selected in (i) above.
(l) Allow sufficient time for TI and resistance thermometer to stabilize,
and record TI temperature and temperature of resistance thermometer
NOTE: Temperature of resistance thermometer is determined by resistance bridge and
resistance ratio table supplied with resistance thermometer.
(m) Compute TI emergent stem correction as follows:
Stem correction - Kn (T - t).
K = 0.00016 for Celsius thermometers
= 0.00009 for Fahrenheit thermometers
T = TI indication in ,C
n = Number of degrees on TI scale from top of liquid level to temperature
indication.
t = Mean temperature of emergent TI stem.
(n) Apply stem correction determined in (m) above to TI temperature
recorded in (1) above, and record result as corrected temperature.
(o) Compare TI corrected temperature recorded in (m) above with
temperature of resistance thermometer recorded in (1) above. Record
deviation of TI from resistance thermometer.
(p) Repeat (k) above three times at 5-minute intervals.
(q) Determine average of deviations recorded in (o) above. If average
deviation is not within ƒ0.05 degree, perform b below.
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