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86 Cards in this Set

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Silicone grease is usually
applied between the heat source and heat sink for better?
thermotransfer
honeycomb rf interference
filter is installed on both input and outlet to prevent
stray rf from entering or leaving the equipment cabinet
Some units of electronic equipment are hermetically sealed to prevent
the entrance of moisture.
ethylene glycol is added to the water to prevent
freezing when the
system is exposed to freezing weather.
Type I
Seawater/distilled water(SW/DW) heat exchanger with SW/DW heat exchanger standby
Type II
SW/DW heat exchanger with a chilled water/distilled water (CW/DW) heat exchanger standby
Type III
CW/DW heat exchanger with a CW/DW heat exchanger standby
Type I (SW/DW) systems are used for electronic system installations that can be operated satisfactorily with seawater temperature as high as?
95°F
Type I (SW/DW) systems result in a distilled water supply temperature to the electronics of approximately?
104°F
Type II (SW/DW,CW/DW) systems are used in installations that cannot accept a DW temperature higher than?
90°F
Type III(CW/DW) systems are used in installations where the temperature range is?
critical
The seawater is from the where and the chilled water is from the where?
sea
ship’s air-conditioning plant
seawater from a sea connection is pumped by what in one of the ship’s engineering spaces?
seawater circulating pump
duplex strainer purpose?
to remove all debris and then through the tubes of a heat
exchanger
it is discharged back into the sea at?
an overboard discharge
Another means of providing seawater is through the
ship’s firemain, the seawater is taken from the firemain through a duplex strainer and a?
flow regulator (orifice plate) to and through the heat
exchanger.
Seawater systems are referred to as open-looped or one-pass because?
the seawater flows through the system only once
A temperature regulating valve at the inlet of the heat exchanger regulates the flow of chilled water through the heat exchanger to?
maintain the
required water temperature in the secondary system
(distilled water)
The secondary cooling system is designed to?
transfer heat from the electronic equipment being cooled to the primary cooling system
The secondary system
is a?
closed-loop water system
The temperature regulating valve is installed to equipment for?
partially bypass distilled
water around the seawater- to-distilled-water heat exchanger so that a constant water temperature can be
supplied to the electronic
As the temperature in the distilled water increases, more water is directed to the what and less to the what?
heat exchanger
bypass line
The size of the heat exchanger is designed to handle?
the full cooling load of the electronic equipment plus a 20 percent margin
Is provided in the distilled water system to compensate for changes in the coolant
volume, and to provide a source of makeup water in the
event of a secondary system leak.
expansion tank
When the expansion
tank is located above the highest point in the secondary
system and vented to the atmosphere, it is called a?
gravity tank
If it is below the highest point in the secondary cooling system, then it is called a?
compression tank
demineralize is designed to ?
remove dissolved metals, carbon dioxide, and oxygen
is installed at the output of the demineralizer to prevent the carry-over of chemicals
into the system and to remove existing solids?
submicron falter (submicron meaning less than one
millionth of a meter)
Type II cooling system is similar to the Type I secondary coolant system and uses many of the same components. The major difference is?
in the operation of the CW/DW heat exchanger
A two-way temperature regulating valve is used in the primary cooling loop to regulate the temperature of the
secondary loop
TYPE III COOLING SYSTEM
In a Heat exchanger secondary coolant (distilled water) flows through the what, the
primary coolant (seawater or chilled water) flows
through the what?
shell
tubes
A what counterflow heat exchanger is more efficient than the what heat exchanger,
because there is a more uniform gradient of temperature difference between the two fluids?
single-pass
double-pass
Results because of dissimilar metals in the cooling system?
electrolysis
Used to prevent electrolysis?
Zinc
The expansion tank serves a threefold purpose in a
liquid cooling system.
1. maintains a positive
pressure required on the circulating pump inlet for
proper operation of the circulating pump.
2. compensates for changes in the coolant volume because of temperature changes.
3. vents air from the system and provides a source of makeup coolant to compensate for minor losses because of
leakage or losses that occur during the replacement of
radar equipment served by the system.
The sight glass should normally show the tank to be?
2/3 to 4/5
low-level alarm switch is usually set at what
percent of tank capacity?
20%
are used in the seawater cooling system to remove debris and sea life
Strainers
consists of a Y-pattern body housing a wire mesh basket.
simplex basket strainer
consists of two removable baskets located in parallel at the seawater inlet
duplex strainer
The purpose of the duplex gauge is to provide?
a visual indication of a clogged strainer basket
When the basket is clogged...
the pressure reading is usually 5 to 10 psi above the clean-basket reading
Acts as a spring-load to seat and hold the basket in the housing
basket handle (spring handle)
This valve used where seawater is the
primary cooling medium in the heat exchanger.
three-way valve
This valve is used where chilled water is the primary
cooling medium.
two-way valve
The three-way
regulating valve’s range of operation is within what
degrees of the setting on the valve?
+ or - 5 degress
contains a volatile liquid that vaporizes
and expands when heated.
bulb
is normally installed in the chilled water supply to
the heat exchanger with the thermostatic sensing bulb
installed in the distilled water outlet from the heat
exchanger.
The two-way temperature regulating valve
Both the three-way and two-way temperature regulating valves have a what to provide uninterrupted service?
manual override feature
simplest design of a flow
regulating device, consisting of a steel plate with a hole
in it.
orifice plate
with the chilled-water system This restricts the flow from the heat exchanger and keeps the heat exchanger fully submerged for greater efficiency
constant flow regulator
constant flow regulator ever used in Seawater?
No because the internal parts would easily become fouled with marine growth and deposits
is used to regulate a major section of the coolings system; whereas, the flow regulator is normally used to regulate an individual feeder line to an individual component or cabinet
pressure-regulating valve
is normally found in the secondary cooling system to
monitor the overall coolant flow.
low-flow switch
The main operating parts consist of a low flow switch?
hermetically-sealed reed switch and a permanent magnet attached to an internal shuttle.
is a variable area orifice
meter that functions by maintaining a constant
differential pressure with varying flow
rotameter
flowmeter as the
coolant approaches the contracted portion (throat) of the meter, its velocity must increase as it flows through the contracted zone.
venturi-type
works in the same manner as
the venturi flowmeter, but its construction is much
simpler and less expensive to manufacture
orifice flowmeter
Each cooling system has how many secondary distilled
water circulating pumps?
two
used in the liquid
cooling system are single-stage centrifugal pumps
closely coupled (pump is built onto the motor) to a
constant-speed electrical motor
circulating pumps
The
demineralize is sized so that what % of the cooling system
volume passes through the demineralize every hour.
5%
three different types of cartridges
first cartridge is the organic removal cartridge.
second cartridge is the
oxygen removal cartridge.
third cartridge is the mixed-bed cartridge
In this position, power is
removed from the sensor loop to facilitate maintenance.
CUTOUT
selector switch position simulates an alarm condition
TEST
This is the position for
acknowledging an alarm
STANDBY
is used primarily to
increase the dielectric constant inside the waveguide to prevent rf energy from arcing inside it.
dry air
high-power waveguide runs, the dry air pressure is approximately
20 to 35 psig
low-power waveguide applications, the dry air is
approximately
1 to 8 psig
Type 1 for dry air
30 lb/inch2
Type 2 for Dry air
60 lb/inch2
Type 3 for Dry air
75 lb/inch2
SPS-48 and SPS-49, are supplied with panels designed for
80 to 125 lb/inch2
dehydrator is used to remove the majority of the water and oil in both liquid and gaseous vapor forms from the air
Type 1 dehydrator (refrigerant)
Type II
desiccant
Type III
(combination of refrigeration
and desiccant)
high-power waveguide system requires dry air at apressure of what with a dew point of - at atmospheric pressure.
25 to35 psig
40°F
is the temperature at which water vapor begins to deposit as a liquid.
Dew point
is to remove oil and water in both forms, automatically and
continuously, and to deliver clean, very dry air for
pressurization of equipment waveguides.
desiccant air dryer
removes oil through a
combination of mechanical means and absorption
telltale oil filter
performs a cleaning step by a process known as adsorption.
purifier-dehydrator
difference between absorption
and adsorption.
Absorption takes place in the telltale oil filter when
it removes oil by soaking it up as a liquid.
Adsorption is a surface and a molecular phenomenon. Mobile gaseous and liquid atoms or
molecules are attracted to the surface of any solid
because of unbalanced forces existing at the surface.
The fluid separator and dump trap consist of two
interconnected assemblies
separator and the automatic trap
is a diaphragm-operated, pressure-reducing valve located downstream from the fluid separator and telltale oil filter.
pressure regulator
consists of two desiccant
chambers filled with desiccant in the form of small
spheres
dehydrator
In one 60-second period, each solenoid valve is open for XX seconds and closed for XX seconds.
22
38
is installed downstream
from the dryer to monitor the dew point of the dry air.
moisture monitor probe