both lock screws. Screw the lifter (fig. 4-39) onto the
bowl shell, and by turning in on the jackscrew the
shell will loosen from the spindle. Using the chain
hoist, lift the shell from the frame.
After the bowl parts have been disassembled,
remove the rubber rings and clean the tubular shaft
and disks with a brush, using JP-5 as the cleaning
fluid. Reassemble in the reverse order.
0-rings and gaskets should never be hung
vertically; lay them neatly on a clean, flat surface.
Hanging will seriously distort the shape of 0-rings
and gaskets. When installing 0-rings, always inspect
them for nicks, cuts. or abrasions; use only good 0-
rings. Examine the 0-ring retaining slots and other
contact surfaces for nicks and burrs, and remove such
before installing the ring. Make sure that the
retaining slot and contact surface are clean, and coat
the 0-ring with a light machine oil before installation.
Maintain the lubrication system in a perfect
condition. Refer to the manufacturer’s instruction
manual and current Instructions about the type and
amount of lubricant.
PRESSURE GAGES
Pressure gages are used throughout the AvFuels
system to measure and indicate pressure so the
operator of the equipment can maintain pressure at
safe and efficient operating levels. A wrong pressure
indication is often the first sign of trouble with the
Figure 4-39.—Bowl shell lifter.
equipment. Any excess or deficiency in pressure
should be immediately investigated.
There are three types of gages the ABF will
typically use in operating the AvFuels system:
Simplex pressure gages, compound gages; and
differential pressure gages.
Simplex pressure gages measure pressure only.
The gage readings range from zero to the gage’s
maximum rated pressure. A Simplex pressure gage
has two pointers: One, usually black or white,
indicates the actual operating pressure of the system
the gage is attached to; the other, usually red, is
manually positioned to indicate the normal operating
pressure of the system the gage is attached to. These
gages are normally installed on the discharge side of
pumps.
Compound gages are nearly identical to simplex
pressure gages, with one exception. Compound gages
can measure vacuum. The gage readings typically
start at 30 inches of vacuum and increase to the
gage’s maximum rated pressure. The pointers are
exactly the same as on the simplex pressure gage.
These gages are normally installed on the suction
side of pumps and the main deck filling connections.
Differential pressure gages are used to measure
the pressure between two pressure lines. A
differential pressure gage has only one pointer and
does NOT measure actual pressure. It measures the
pressure DIFFERENTIAL between two pressure
sources. These gages are normally installed on
vertical and reclaim filters.
TANKS
Storage of aviation fuel aboard carriers has
always presented a serious fire and explosion hazard.
With the introduction of JP-5 as the primary jet fuel,
hazards in handling were lessened and, because of
the high flash point of JP-5 (minimum 140°F),
protective storage is not required.
Basically, there are four types of JP-5 tanks:
wing, deep centerline, double-bottom, and peak
tanks. See figure 4-40 for the types and locations of
JP-5 tanks.
Tank types generally relate to the relative
location of the tanks in respect to the hull of the ship.
Wing tanks are deep tanks located in a forward
and aft row along the contour of the hull on the port
and starboard sides of the ship. There are normally
two rows of wing tanks on each side. These tanks are
located between voids and are an integral part of the
ship’s underwater protective system. The top of the
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