Introduction - PAC Alcor JFTOT II Manual

1. INTRODUCTION

1.1 The Calibration Manual provides procedures to
calibrate or check three major components.
Examples of displays are shown to illustrate the
calibration procedure. The dates, times, tem-
peratures, and pressure readings are provided
only as examples, and will vary to reflect the
actual condition of the equipment.
1.1.1 Calibration of Heater Tube Tempera-
ture Controller (AUTOCAL). This
procedure should be performed at least
once every six months.
Checking Validity of ∆P Transducer.
1.1.2
This procedure should be performed at
least once every six months.
1.1.3 Checking Validity of Fuel Flow Rate.
1.2 The AUTOCAL procedure provides calibration
of the temperature controller and heater tube
thermocouple using three temperature stan-
dards:
• Ice bath, 0°C
• Freezing point of Tin (Sn), 232°C
• Freezing point of Lead (Pb), 327.5°C.
The heater tube thermocouple is exposed to
each of the temperature standards. The
JFTOT measures and records the temperature
detected for each standard. Then corrections
are calculated to display calibrated tempera-
tures.
NOTE - A quick reference card is provided as a
guide when performing the AutoCal procedure.
This card, entitled "JFTOT II CALIBRATE THER-
MOCOUPLE OPERATION," is on the opposite
side of the main operations card. This card can
be placed near or attached to the JFTOT for
quick reference.
1.3 The standardization of the ∆P transducer is done
by applying a defined pressure that is created by
a fuel of known density at room temperature.
The term "standardization" is used here instead
of calibration to differentiate between the work
that can be done to assure the transducer is
operating properly (standardizing) and the
absolute value that only can be verified with the
ALL OPERATORS MUST READ ALL OF SECTION 3 IN THE
OPERATION MANUAL BEFORE USING THE JFTOT II.
JFTOT II Calibration Manual Rev. C
Bureau of Standards procedures and specially
calibrated instruments (calibrating). For our
purposes, standardizing is sufficiently accurate to
determine if there is a problem with a transducer.
Basically, the air is removed from the lines
throughout the system and the transducer is
zeroed. Then a measured height of fuel is added
and the theoretical differential pressure calculated.
This value is compared to the value displayed on
the screen. The difference, if any, should fall
within a small range of acceptable error. Values
beyond this minimum error are suspect, and the
test should be performed again to confirm the
error. If confirmed, a persistent error suggests
that a transducer may have drifted in accuracy; it
can then be calibrated by existing Standard
techniques.
The transducer is factory calibrated to give a
pressure reading that is equivalent to that which
would result from using the original fuel/mercury
manometer. When a static check is made to
confirm that the transducer is functioning properly,
the reading includes the offset tare for the flow
compensation and the bias due to the basis being a
mercury-kerosene manometer. The readings,
therefore, are consistent with all JFTOTs (ASTM
D3241) (see description of the differential pres-
sure system in the Operation Manual Appendix).
1.4 The standardization of the flow rate is done by
determining the amount of fuel displaced during
the test, then calculating the flow rate. The term
"standardization" is used here instead of calibra-
tion to differentiate between the work we can do
to assure the pump system is operating properly
(standardizing) and the absolute value that only
can be verified with Bureau of Standards proce-
dures and specially calibrated instruments (cali-
brating). For our purposes the standardizing is
sufficiently accurate to determine if there is a
problem with the flow rate.
Basically, the volume of water that drips from the
air trap assembly during the 150 minute test period
when the heater is on is measured. The fuel
pumped is equal to the volume measured. Flow
rate is calculated by dividing the Fuel Displaced by
the Elapsed Time.
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