flows through the reducing valve where it is
it to 190F, and distributes it to the masker
reduced to 38 psi. It then branches out into two
emitter rings outside the ship's hull. This reduces
piping systems going to the demister pads. When
or modifies the machinery noise being transmitted
anti-icing is activated, bleed air is discharged
through the hull to the water. Refer to figure 4-11,
on the inlet side of the demister pads through
a diagram of the CG, and DD masker air
flexible piping to prevent icing on the demister
system, to help you understand the following
pads for both module cooling air and combustion
paragraphs.
air. Bleed air is also provided to the intakes for
Bleed air at 500 to 800F and at 75 psig from
module cooling and combustion air to heat the
the bleed air header enters the masker air system
inlet air after it has passed through the demister
within each engine room and is directed to the
pads.
masker air cooler valve. After the hot bleed air
has passed through the masker cooler valve, it is
MASKER AIR SYSTEM
piped to the masker air cooler where it is cooled
to 190F. The masker air cooler is a shell and tube
Because of the existing differences between the
type of cooler. It uses seawater as the cooling
ship classes, we will describe their masker air
medium. The cooled masker air is piped through
systems separately.
to the masker air filter to remove any solid
contamination and then to the masker/start
transfer valve. The masker/start transfer valve
CG, and DD Masker Air System
controls the flow of the 190F masker air to either
The CG, and DD, masker air system
the masker air system or to the gas turbine
takes hot bleed air from the bleed air system, cools
start/motor air system. Push buttons at the
Figure 4-11.--CG, and DD masker air system.
4-20
