Figure 2-10.--Views through a refractometer.
Remove the black plastic rod from the
bottom of the refractometer. Using the rod
(or a screwdriver), adjust the setscrew
In the oil lab, your job of sampling and
until the shadow line meets the zero line of
critical to the effective operation of your ship's
views A and B.)
engineering equipment and systems. Oils
reduce friction, dissipate heat, and prevent
corrosion. In addition, they conduct friction-
generated heat away from bearings, act as a
seal to protect lubricated areas from
What you have done is added water to the
fuel. By shaking the sample, you
materials such as rust preventatives, anti-
allowed the icing inhibitor to leach into the
water. By adjusting the setscrew until you
read zero, you have made the refractometer
ready to compare the FSII in the fuel to the
scale inside the instrument.
equipment. Contamination occurs in oils
much in the same manner as it does in fuels.
Open the plastic cover and wipe the
Whereas fuels are really used only once, oils
water from the window and cover.
are purified and used over and over again.
Carefully turn the drain cock so several
This is where a good sampling and testing
drops of water can trickle into a clean,
program comes into play.
dry aluminum dish. Open the hinged
plastic cover and place two or three
In the following sections, we will discuss
drops of water from the funnel on the
typical sampling and testing procedures for
window. Close the cover. Look through
oils. In most of our discussions, we will use
the eyepiece and read the point where
2190 TEP as a typical oil because you will
the shadow line is on the scale. This
come into contact with this oil more than any
reading should give you the percentage
of the others. Later in this section, we also
of FSII by volume. (Study view C.)
will tell you about the other types of oils and
the sampling and testing procedures you will
be required to perform on them. Because you
will perform sampling more frequently than
Remember to put only water on the
testing, let's talk about oil sampling first.
refractometer, no fuel. Use clean water or
water with additives only. If fuel is in the
sample you put on the refractometer, you may
get a false reading.
Oil sampling will always be your simplest,
most frequently used, and first-line procedure
Upon completion of the test, empty the
of defense against equipment failure. While
funnel and properly dispose of the fuel.
assigned to the oil lab, you will need to know
Clean the equipment with soap and
the conditions for which you
water, then thoroughly rinse it with