FED-STD-791D
b. Turn on pump, and continue to add oil until level in coking head glass is at or
slightly above the mark 3.8 cm ([1-1/2 in] below top of glass).
c. Fill humidifier half full of distilled water, and adjust air flow control valve to
give an air flow of approximately 150 mL/min.
d. Turn on the coking tube heater, and set controller for 274C (525F). (It is
imperative that this temperature is not exceeded during flow check since higher
temperatures would cause coke formation). As the test oil heats and expands,
drain as necessary to maintain a visible level in the coking head. It is desirable
to have the oil level close to the top of the coking head glass. Valve (29) must
be kept open.
e. Turn on the cooling water, and check the operation of the water solenoid valve
by adjusting "oil-in" temperature controller to open and close solenoid, keeping
water by-pass valve (17) closed and water trim valve (16) wide open. (When
water flow is shut off, the cooler should drain in 10 s or less.)
f. Set "oil-in" temperature control to 149C (300F), keeping water-bypass valve
(17) closed and water-trim valve (16) wide open.
g. As soon as "oil-in" temperature is above 121C (250F), check the setting of
bypass relief valve (34) by cutting off filter flow at valve (35). Adjust the relief
valve to give a pressure of 34.5 kPa gage (5 psig) higher than obtained when
flowing through the filter.
h. Open valve (35) to direct flow through the filter.
i. Shut off coking-tube heater as soon as the "oil-in" temperature reached 138C
(280F). Check hot flow rate by measuring the time required for a discharge of
100 mL of oil through three-way valve (28). Pour the 100 mL of oil back into
the filler tube immediately, keeping valve (29) open. Calculate the flow rate in
mL/min.
j. Turn on the coking tube heater.
k. If first hot flow check shows a rate of 300 5 mL/min, record the actual flow
rate and proceed to step (1). If the flow rate is outside this limit, readjust the
variable-speed-transmission speed control (14) to correct for the difference, and
repeat steps (i) and (j) until a flow rate of 300 5 mL/min is obtained.
l. Direct oil flow through the bypass valve (34) by blocking the flow through the
filter, and again check the hot oil flow as in step (i). If the flow rate is above
255 mL/min, record this value and proceed to 6.15. If the flow rate is below
225 mL/min, the pump is worn or defective and must be replaced or rebuilt
before proceeding further. In this event, after replacing or rebuilding the pump,
repeat 6.13 and 6.14.
NOTE 4:
The entire sequence of flow check procedure (steps j though l) must be
completed within 30 min to avoid excessive oil deterioration.
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