Vibrations are generated in the ultrasonic cleaner
dirt accumulations and the air filters in the generator
(fig. 5-17) by transducers. These transducers are
compartment door should be cleaned or replaced
welded to plates, called diaphragms. When the
periodical y according to PMS requirements. The
generator fans and cleaner unit blower should be oiled
transducers arc energized, they produce extremely small
vibrations in the plates, 1 or 2 thousandths of an inch
once a year and the water pump should be oiled every 6
months.
(0.001 to 0.002 inch) but with strong accelerating forces.
As the plates vibrate, they cause whatever medium they
are suspended in to assume a similar frequency and
SUMMARY
transmit that frequency throughout the vessel. The
plates are, in effect, a Hi-Fi speaker operating at one
The ultrasonic cleaner is one of the most essential
frequency.
machines on board when it comes to conducting repairs
to other pieces of machinery. Its ability to clean parts
When the medium through which the waves are
and some metallic ventilation filters makes it mandatory
transmitted is a liquid, there is good transmission and
that preventive maintenance procedures be strictly
very little loss of strength since all liquids are relatively
followed to ensure it stays operational.
incompressible. The physical shock of the vibrations on
the item being cleaned cause a "scrubbing" action much
better than a brush because the size of the sound waves
ELECTROSTATIC VENT FOG
allows for cleaning of minute holes and crevices that
PRECIPITATOR
would be impossible for a brush.
The electrostatic vent fog precipitator (fig. 5-18) is
mounted in the lube oil system of reduction gears for
MAINTENANCE
main engines and generators. The purpose of the vent
fog precipitator is to remove entrained oil mist from the
The ultrasonic cleaner is extremely rugged and
vented air of the reduction gears before it is discharged
requires little maintenance other than cleaning and
oiling. The components should be kept free of dust and
into the engine mom or space.
Figure 5-17.--Block diagram of ultrasonic cleaner.
5-30
