auxiliary machinery and associated equipment Flashcards
1
Q
what is meant by the term positive displacement pump?
A
each stroke displaces a definite quanitity of liquid, regardless of the resistance against the pump
2
Q
what is an example of a positive displacement pump?
A
reciprocating or rotary pump
3
Q
what are the two main parts of a reciprocating pump?
A
water end and steam end
4
Q
if a riciprocating pump is driven by an electric motor, what is this pump referred as?
A
power pump
5
Q
what is the most common type of reciprocating pump used in the Navy?
A
direct-acting with double action
6
Q
what is meant by the term direct-acting?
A
this is when the pump rod is a direct extension of the piston rod
7
Q
what does the term double-acting refer to?
A
each stroke serves both to draw in liquid and to discharge liquid
8
Q
how is it determined whether a pump is high or low pressure?
A
dependent on the size of the steam cylinder in relation to the size of the cylinder in the liquid end
9
Q
what pressure would a reciprocating pump have, if the steam cylinder was larger than the cylinder in the liquid end?
A
high pressure
10
Q
the term high pressure, when associated with reciprocating pumps means what?
A
that the pressure being discharged is greater than the steam that drives the pump
11
Q
if a reciprocating pump has identified as 12x8x16 VSDA, what would this refer to?
A
the pump has a 12 inch steam cylinder, an 8 inch water cylinder, a 16 inch inch stroke, and is vertical single double-acting pump
12
Q
what is the purpose of cushioning valves at each end of the steam cylinder?
A
these valves are adjusted to trap a certain amount of steam at the end of the cylinder, thus cushioning each stroke.
13
Q
what part of a reciprocating pump is referred to as the power end?
A
steam end of the pump
14
Q
what is the function of the snifter valves?
A
emergency feed pump
15
Q
what publication can you use to find pertinent information on pumps?
A
NSTM 503
16
Q
groaning in the pump end of a reciprocating pump is generally caused by what?
A
over tightening of the pump packing
17
Q
what type of pump works by means of rotating parts, which trap liquid at the suction side, and force it through the discharge outlet?
A
rotary pump
18
Q
rotary pumps are particularly useful for pumping what type of fluids?
A
oil and other heavy viscous fluids
19
Q
why are rotary pumps are particularly useful for pumping what type of fluids?
A
to minimize slippage from the discharge side to the suction side
20
Q
if rotary pumps are operated at higher than normal speeds, what will occur?
A
erosion and excessive wear
21
Q
what type of pump is frequently used as lubricating pump on pumps and other auxiliary machinery?
A
simple gear pump
22
Q
what is the major advantage of using a helical gear pump?
A
smoother discharge and increased capacity
23
Q
what is used on a helical gear pump to properly maintain alignment and reduce friction on the gear shaft?
A
roller bearings
24
Q
what is used on a helical pump to prevent leakage at the shafts?
A
stuffing boxes
25
what type of pump uses the throwing forces of a rapidly revolving impeller?
centrifugal pump
26
the main feed pump is an example of what type of pump?
centrifugal
27
where does the liquid enter the impeller on a. centrifugal pump?
the eye (center)
28
capacity and discharge pressure can be varied on a centrifugal pump by changing what?
pump speed
29
what term refers to the flooding of the pump casing with fluid before it can operate?
pump priming
30
what prevents the main feed pump from overheating at no load and low load conditions?
recirculating lines
31
what is installed on a. centrifugal pump, to eliminate the renewing of an entire impeller and pump casing due to rapid wear?
wearing rings
32
what is installed on the pump shafts to prevent the total replacement of the shaft due to excessive wear and scoring?
shaft sleeves
33
what is the function of seal piping?
to cool the shaft and packing. and to seal the joint between the shaft and the packing against air leakage
34
seal piping leads liquid from the discharge side of the pump to the annular space within what component?
lantern ring
35
main feed pumps are fitted with what two types of governors?
constant-pressure and speed-limiting
36
what supports the weight of the impeller and maintains the position of the impeller both radially and axially?
bearings
37
to minimize leakage from the discharge side of the pump casing to the suction side of a centrifugal pump what must not be maintained?
close clearances
38
what is meant by the term axially flow?
liquid flow that is parallel to the shaft
39
why are centrifugal pumps located below the level from which suctions is to be taken?
to simplify pump priming
40
a main feed pump is classified as what type of pump?
multistage, high speed, turbine driven
41
what provides a positive suction head to the main feed pump?
feed booster pump
42
impellers on main condensate pumps are constructed from special materials to resist what?
cavitation
43
how is entrapped air removed from pump casings?
vent valves
44
what is the function of water flinger rings installed on main feed pump shafts?
to prevent stuffing box leakage from following along the shaft and entering the bearing housing
45
in order to feed the boiler the main feed pump must operate above steam drum pressure?
at least 150 psig above drum pressure
46
how often are main feed pumps checked for proper operation while online?
hourly
47
what type of pump is the main air ejector?
jet pump
48
what is the primary use of jet pumps onboard ship?
to remove air and other noncondensable gases from main and auxiliary condensers
49
what type of jet pump uses liquid rather than steam to operate?
educator type
50
a jet pump contains how many moving parts?
none
51
on a main lube oil or lube oil service pump filled with a constant-pressure governor, were does oil actuating line connect?
discharge side of the pump
52
what is the purpose of the needle valve installed on the constant-pressure governor?
reduces hunting, and stabilizes pump discharge pressure
53
what device allows a steam turbine to operate under all conditions from no load to overload but will not exceed 110 percent of normal operating speed?
speed-limiting governor
54
on a centrifugal-mechanical type governor what causes the steam admission valve to open and close?
the movement of the flyweights and spring compression
55
what device ensures that the steam turbine will not exceed a predetermined speed and shuts off the steam when the turbine exceeds 110 percent?
overspeed trip
56
carbon packing rings must never be lubricated with what?
grease oil
57
the final diameter of the carbon ring jig, including the raised cutting edge, should be equal to what?
the required inside diameter of the carbon ring
58
carbon rings are held together with what type of fastener?
springs
59
when carbon rings are properly fitted what type of joint is formed?
butt joint
60
what systems use carbon rings?
low pressure and low temperature
61
how are carbon rings prevented from rotating with the shaft?
by lugs attached to the springs
62
when examining the shaft after carbon ring ring removal, you notice scoring on the shaft, what is the corrective action?
smooth the shaft with an oil stone
63
labyrinth packing segments are held in place by what?
springs
64
what is the operating principle of labyrinth packing?
the steam passes along the shaft, the pressure drops in the labyrinth
65
what device is designed to take care of very slight misalignment between the driving the driven shafts?
flexible coupling
66
what are the three kinds of friction?
sliding, rolling and fluid
67
what is the maximum allowable temperature rise in oil through a bearing?
50 degrees F
68
what is the maximum allowable bearing temperature?
180 degrees F
69
what are radial sleeve bearings lined with?
Babbitt metal
70
in what publication would you find general information on all bearings?
NSTM 244
71
what type of bearing measurement with the lead wire and micrometer method, how is a reading attained?
by measuring the leads in a several places to see whether they are uniform and measuring them to determine the clearance
72
what size of lead wire is used for bearing measurement?
lead wire must be .003 inch thicker than the desired bearing oil clearance
73
what type of bearing measurement uses a feeler gage to determine clearances?
bridge gage method
74
when using a mandrel to hand fit a bearing, what can be used to indicate high spots on the bearing surface?
Prussian blue
75
what is used to dissipate heat on a radial sleeve bearing?
babbitt metal
76
what rides against the thrust collar, on a kingsbury thrust bearing?
shoes
77
what type of bearing is used for high speeds and heavy loads?
Kingsbury thrust bearing
78
how are the shoes kept in alignment and equalized with pressure?
by leveling plates
79
how is a thrust clearance reading taken on a kingsbury thrust bearing?
by moving the shaft axially in each direction and by measuring the amount of end play with a dial indicator
80
what is babbitt composed of?
lead base and tin base alloys
81
what is another name of a anti friction bearing?
ball bearing
82
what is the function of flexible couplings?
to join the driver and driven shafts and take care of very slight misalignment between the driving and driven shafts
83
what is the flexible comment in a grid type coupling manufactured from?
spring steel
84
when should oil coolers be put into operation on auxiliary machinery?
when the temperature of the lube oil leaving the cooler is 100 degrees F
85
what are the two main types of forced draft blowers used onboard naval ships?
centrifugal and propeller
86
force draft blowers serve what function?
to furnish a large amount of air required for combustion of the fuel oil
87
as a rule, how many main force draft blowers are provided per boiler?
two
88
how is the air intake protected to prevent entry of foreign objects?
screened intakes
89
what publication lists general information on all force draft blowers?
NSTM 554
90
What is the function of the diffuser vanes installed downstream from the fan wheel?
to straighten the air flow as it leaves the blower
91
when the blower is secured, what is the position of the shutters?
locked closed
92
failure to lock the shutters on an idle blower can result in what, if another blower is operating?
windmilling of an idle blower
93
what is the discharge duct of the force draft blower connected to?
boiler air casing
94
on blowers that use nozzle valves, how are they designed to control speed?
by opening in sequence
95
what is the major difference between centrifugal and propeller blowers?
direction of air flow
96
what is the most common force draft blower found onboard naval vessels?
propeller type
97
how is the blower speed checked for revolutions per minute? (RPM)
by the use of tachometers
98
what is installed to prevent the force draft blower turbine from exceeding the maximum safe operating speed?
speed limiting governors
99
what is the power source of the port use blower?
electric motor
100
what type of lubrication system is installed on steam force draft blowers?
force feed
101
what is the temperature of the oil cooler outlet maintained at on all steam driven auxiliary machinery?
between 120 degrees F and 130 degrees F
102
what are the stationary diffuser blades on a vane axial force draft blower called?
stator blades
103
what is the FDB tachometer, that is driven by the governor spindle calibrated to indicate?
main shaft speed in revolutions per minute (RPM)
104
what device prevents carryover in the distilling plants?
moisture or vapor separators
105
what does the term evaporating refer to?
the progress of boiling water setter to separate it into feed water vapor and brine
106
in the distilling plant what is the first stage of distillation defined as?
evaporation
107
what is the second stage of distillation in the distilling plant called?
condensation
108
in the distilling process the term vapor means?
the end product of the evaporated seawater
109
what is the most widely used distilling plant in the navy?
flash type
110
what is the major heating source of the seawater heater?
auxiliary exhaust
111
what type of heat exchanger is used for fuel and lube oil coolers?
counterflow
112
the main condenser is an example of what type of heat exchangers?
cross flow
113
what are the five classifications of heat exchanger?
path flow, direction of flow, number of passes, type of surface, type of construction
114
what does the term parallel flow mean?
when both fluids flow in the same direction
115
what doe the term counter flow mean?
when the flow fluids flow in opposite directions
116
what does the term crossflow mean?
when one fluid flows at ring angles to another
117
if the surface of a heat exchanger is fitted with rings, fins, studs, or some other kind of extension it is termed what type?
extended surface
118
what publication lists general information on heat exchangers, condensers, and air ejectors?
NSTM 254
119
A condenser changes a gas to a liquid by causing the gas to?
lose its latent heat
120
what type of heat exchanger is the deaerating feed tank (DFT)
direct contact
121
a plain surface heat exchanger is constructed to have what type of surface?
very smooth
122
what type of heat exchanger is constructed of pairs of flat oblong strips?
strut tube and plate tube
123
what type of heat exchanger is constructed to have one tube inside another?
double tube
124
what type of heat exchanger is constructed to have coils of tubing?
helical or spiral tube
125
what type of heat exchanger uses U shaped tubes on one tube sheet?
return bend
126
what is the function of an air ejector?
to remove air and noncondensable gases from condensers
127
how is flow through the air ejector maintained?
by jet of high velocity steam passing through a nozzle
128
what is the first stage of the main air ejector called?
intercondenser
129
what is the second stage of the main air ejector called?
aftercondenser
130
where does the aftercondenser take a suction from?
intercondenser
131
what is used to cool the main air ejector assembly?
condensate
132
what prevents the main air ejector from overheating?
thermostatic recirculating valve
133
what system provides steam to the main air ejector?
auxiliary steam system
134
what are the three functions of the main air ejector?
initiates the vacuum in the main condenser
helps maintain the vacuum in the main condenser
removes air and noncondensable gases
135
what is meant by the term helical flow turbine?
when steam enters at a tangent to the periphery of the rotor and impinges upon the moving blades
136
what are the blades on a helical turbine called?
buckets
137
what is the primary purpose of the turbine wheel or rotor?
to carry the moving blades
138
what converts the thermal energy from the steam into rotary movement of the shaft?
the moving blades
139
what is the purpose of the equalizing hole drilled through the rotor on an impulse turbine?
to prevent the development of a pressure difference between the two sides
140
how are impulse blades attached to the rotor?
by either an inverted circumferential dovetail or a pine tree dovetail
141
on an impulse turbine what is the function of the nozzle?
to guide the steam from the steam chest to the moving blades
142
what are the three functions of the deaerating feed tank?
to free the condensate of oxygen and other noncondensable gases
to preheat the feed water
to act as a reservoir in which to store feedwater
143
what is the major heating source of the deaerating feed tank?
auxiliary exhaust
144
the deaerating feed tank is designed to operate at what pressure and temperature?
15 psig and 240 to 250 degrees F
145
what assists the deaerating feed tank atomizing valve in opening?
high pressure drains
146
what protects the deaerating feed tank from excessive internal pressure?
a relief valve
147
what pressure is the deaerating feed tank relief valve set to lift at?
approximately 30 psig
148
what device is installed on the deaerating feed tank to protect it from excessive external pressure from the atmosphere?
vacuum breaker
149
what is the deaerating feed tank vacuum breaker set to lift at?
approximately 13 psig
150
what is the minimum recirculation time of the deaerating feed tank, prior to alignment to the feed system?
10 minutes
151
normally, what is the pressure drop between the auxiliary exhaust steam line and the deaerating feed tank?
1/2 psig or less
152
what component receives a steam-air mixture from the deaerating feed tank and from the glands of auxiliary steam turbines?
gland leakoff condenser
153
what is installed in the deaerating feed tank to minimize turbulence of the water, due to the ships movement?
swash plates
154
what two types of lube oil purifiers are currently in use today?
delavel and sharples
155
a disk type purifier would be constructed by what manufacturer?
delavel
156
a sharples purifier uses what typeof rotating element?
a tubular type
157
both lube oil purifiers employ what type of force to separate water from the oil?
centrifugal
158
for maximum efficiency lube oil purifiers should be operated in what manner?
operate the purifier at maximum designed speed and rated capacity
159
when oil becomes emulsified you should lower the percent of lube oil purifier rated capacity to?
80 percent at rated capacity
160
when a purifier is being operated as a separator the bowl must be primed with?
fresh water
161
how often must you clean an operating lube oil purifier?
it is dependent on the amount of foreign matter in the oil. if the amount of foreign matter is not known you should shut down the purifier and check it. cleaning is normally accomplished after 12 hours of continuous sump to sump purification
162
if the water seal fails on an operating purifier what could be the end result?
lube oil can be dumped to a drain tank or the bilges
163
what can be used to preheat the lube oil prior to it reaching the lube oil purifier
a steam heater
164
information on proper idle condenser lay up can be found in what NSTM?
NSTM 254
165
what is the composition of main condenser tubes?
90/10 copper nickel alloy
166
what divides the main condenser seawater side and condensate side?
a tube sheet
167
ship's not equipped with air ejectors establish main condenser vacuum by
by using vacuum pumps
