e. Preliminary Instructions
(1) The instructions outlined in this section are preparatory to the calibration
process. Personnel should become familiar with the entire procedure before
beginning the calibration.
(2) Items of equipment used in this procedure are referenced within the text by
common name and item identification number as listed in tables 5 and 6. For the
identification of equipment referenced by items number prefixed with A, see table
5, and for prefix B, see table 6.
f. Equipment Setup
(1) Remove TI from protective case.
(2) Inspect TI bulb and stem for foreign matter and evidence of deterioration.
(3) Hold TI in vertical position and verify that bulb and column are free from gas
bubbles and that stem is free from globules of liquid. If not, perform (1), (2), or
(3) below as applicable.
(a) Eliminate gas bubbles in TI bulb by cooling with dry ice or equivalent
coolant until liquid is drawn into bulb. Tap TI gently against pad of paper.
Bubbles should rise to surface and disperse. Hold TI upright while
allowing it to return to room temperature.
(b) Eliminate gas bubble from stem of TI with expansion chambers by
slowly and carefully heating bulb until bubbles are joined. Carefully tap TI
against pad of paper or against palm of hand.
CAUTION
To avoid damage to TI, exercise extreme care when applying heat. Do not
heat with open flame.
(c) Eliminate globules of liquid inside TI stem by carefully and slowly
heating TI bulb until liquid column merges with globules.
NOTE: If globules tend to unite and reappear after bulb cools, obstructions or oxidation
of mercury may by present, and TI must be rejected.
(4) Prepare temperature standard (A9) for proper ice mantle formation.
g. Zero Point Temperature Check
(1) Performance Check
NOTE: Unless otherwise specified, verify the results of each test and take corrective
action whenever the test requirement is not met before continuing with the calibration.
(a) Insert TI (model 62C) into temperature standard (A9) so that top of
mercury column is below top of mantle.
NOTE: If necessary, an ice bath may be substituted for temperature standard.
(b) After at least 3 minutes, record TI temperature indication.
NOTE: To minimize emergent stem error, observe indication through cell just above ice
mantle.
(c) Repeat (a) and (b) above two times at 5-minute intervals.
(d) Average the three indications recorded in (b) above. If average
indication is not within ƒ0.05 degree centigrade, perform (2) below.
(e) Repeat technique of (a) through (d) above for remaining TI's listed in
table 7. Average indication will be within limits specified.
(2) Adjustments
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