This test method describes a procedure for determining the deposit
and sludge forming
tendencies of aircraft gas
turbine lubricants when a sample
of the oil is circulated under
controlled conditions for a prescribed
period of time through an
aerated test chamber containing
an aluminum tube
held at a constant temperature.
The coking tube is held at 590 degree F while oil heated
to 300 degree F is circulated by a pump
from the chamber through a
cooler and a line filter and back
into the chamber. The oil flow is
regulated to 300 ml per minute while air flow is the same amount.
At the end of
the test, the weight of solid decomposition
products on the
heated tube and in the
line after are determined. Also, changes
in the viscosity and neutralization number
of the oil can be determined if
desired.
