PAC Alcor JFTOT II Manual page 45

regulator, then drips from a line into an open
container. The drip line allows visual
monitoring of the flow rate.
A2.4 Cooling System
A self contained, closed loop cooling system
provides for bus connector cooling. The JFTOT
has a flow adjustment valve and rotameter type
flow indicator to set the rate at 10 Gal/hr (38 ± 8
L/h). A coolant reservoir provides coolant to a
water pump. The water is pumped through a fan
cooled radiator to cool the water before entering
the bus bars. The water lines are electrically
insulated from the bus connectors by means of
polyethylene tubing. The water flows through the
flow control valve and the rotameter before
returning to the coolant reservoir.
A2.5 Fuel Aeration System
• A system provides dry, filtered air at 1.5
L/min for 6 min. The 9.0 liters thus passed
through the fuel ensures at least 97% of
air saturation. An air pump, flow adjust-
ment valve, and rotameter type flow
indicator provides the air flow. The
JFTOT automatically turns the air pump
off after 6 min.
• A silica gel filled container is used to dry
and filter the air before it enters the fuel.
• A sintered glass tube is used to bubble the
air through the fuel in a sparging action.
A2.6 - Electrical System
1. Heating and Temperature Control System
• The heater tube is heated by conduction of
an electrical current of approximately 200
to 300A at 0.3 to 0.5 VAC. The heater
tube is clamped at each end into busses
having corrosion resistant contact sur-
faces. The busses are cooled by internal
water lines; they receive electrical power
from a low voltage transformer that is
matched to the electrical resistance of the
heater tube.
• The JFTOT provides both temperature
JFTOT II Operation Manual Rev. C
indication (MAN mode) and automatic
control (AUTO mode). The input signal to
the JFTOT computer is from a thermo-
couple inserted through the top of the
heater tube and positioned at the point of
maximum temperature. This thermocouple
can be positioned at any point along the
heated portion of the tube for the purpose
of obtaining a temperature profile. The
sliding scale assembly is provided to define
the position of the thermocouple junction
with the 0.0 position being the heater
tube's lower shoulder.
2. Differential Pressure Measurement System
• A Differential Pressure Transducer
(DPT) is used to measure the differential
pressure across the test filter as the filter
fouls with products from the fuel degrada-
tion. The transducer is connected across
the test filter as per Figures A2.2.1
through A2.2.4. The DPT is controlled by
two valves: FLOW CONTROL SELEC-
TOR VALVE and an electric bypass
valve located inside the JFTOT. The first
valve provides a means to vent and
eliminate any air from the system when
required. The second valve allows the test
fluid to bypass the filter. The bypass valve
is operated automatically by the JFTOT
when the pressure across the filter
exceeds 250 mm Hg. This allows the test
to continue to obtain heater tube deposits
for the full test period.
• The JFTOT records the following:
a. the differential pressure every 30 min.
b. the time when the pressure reaches 2,
10, 15, 25, 50, 75, and 125 mm Hg
respectively.
c. the time to 25 mmHg, the maximum DP,
and the time to open bypass for view on
the display at the end of the test.
• The differential pressure system is cali-
brated to include a 6% bias. This bias is
added to make DPT readings equivalent to
the early JFTOTs that used a mercury
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