Boilers Flashcards

1
Q

Steam is produced as water is heated at its boiling point at ___ F

A

212F at atm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Thermal efficiency

A

Ratio of heat absorbed by the water to the heat provided by the fuel.

I.e. - 100% thermal efficiency occurs when all heat supplied by the fuel is absorbed by water in the boiler

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Feedwater

A

Combination of condensate and make-up water. Is also treated.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Fahrenheit conversion

A

F = (1.8 x C) + 32

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Complete combustion

A

Combustion that occurs when all fuel is burned using the minimum amount of air above the theoretical amount of air required to burn the fuel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Approximately how many lbs of air is required to burn a lb of fuel?

A

14-15lb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

MATT

A

M - mixture of fuel and air
A - atomization to break up fuel into small particles to max contact of fuel with air
T - temperature
T - time required to achieve complete combustion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Fire tube boiler

A

A boiler in which heat and gases of combustion pass through tubes surrounded by water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Water tube boiler

A

Water passes through tubes surrounded by gases of combustion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

A low pressure steam heating boiler is a boiler operated at pressures of not more than ___

A

15 psi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

A low pressure hot water heating boiler is a boiler in which water is heated for the purpose of supplying hot water at pressures of not more than ____ and temperatures of not more than ____

A

160psi

250F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which section in the ASME code applies to steam boilers up to 15psi?

A

Section IV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which section of the ASME code capture the requirements for power boilers for industrial processes?

A

Section I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The safety valve capacity must equal or exceed the boiler______

A

Pounds per hour rating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The ASME Boiler and Pressure Vessel Code states that all boilers with more than 500sqft of heating surface shall have ?

A

Two or more safety valves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The capacity of the safety valve must be large enough that what for low and high pressure boilers?

A

LP - cannot rise more than 5 psi above the MAWP

HP - cannot rise more than 6% above the highest pressure at which any valve is set, but not 6% above the MAWP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Hydrostatic Pressure

A

Weight of water (.433 psi per vertical foot)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

At what temperature do minerals and salt form scale?

A

150F approximately

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Continuous blowdown

A

A blowdown that discharges boiler at a controlled rate to regulate proper chemical concentration in the boiler water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Operating Control

A

Pressure control that senses steam pressure and automatically signals the burner to initiate the start-up sequence when steam pressure is needed and initiate the burner shutdown sequence when steam demand is met.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

High Limit Control

A

Pressure control that senses steam pressure automatically shutdown the burner if the operating control fails.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

ASME Controls and Safety Devices for Automatically Fired Boilers (CSD-1) requires a high limit control to have?

A

A manual reset that requires the operator to reset the control before operation can be restarted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Modulating Control

A

A pressure control that works with the operating control to vary the burner firing rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Water expanding into steam has an expansion rate of approximately ______ times its original volume at atmospheric pressure.

A

1600

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
To change 1lb of water at 212F to 1lb of steam at 212F requires _____ BTU.
970.3
26
Every 11 degrees added to the feedwater prior to going into the boiler increases boiler efficiency by?
1%
27
Thermostatic steam trap
Has a bellows filled with a fluid that boils at steam temperature. The bellows expands or contracts depending on whether it is surrounded by steam or condensate.
28
Float thermostatic steam trap
Has a ball float that opens and closes a discharge valve depending on the amount of condensate in the chamber
29
Inverted Bucket Steam Trap
Steam enters the bottom and flows into an inverted bucket.
30
Distillate Fuel
Fuel oil that has low viscosity and includes No. 1 and No. 2 fuel oil
31
Therm
The quantity of gas required to produce 100,000 btu
32
How many lbs of air is needed to burn a pound of fuel.
14 to 15 lbs of air
33
Air proving switch
An air pressure-actuated switch that closes after proving sufficient pressure of combustion air from the forced draft fan.
34
Turndown ratio
Is the ratio of the maximum firing rate of the burner to the minimum rate
35
Draft
The flow of air or gases of combustion caused by a difference in pressure between two points
36
Breeching
A duct used for the transport of gases of combustion from the boiler to the stack
37
Induced draft
Mechanical draft from air pulled through the boiler furnace with fans located in the breeching
38
Manometer
A device that measures draft by comparing pressures at two location and is measured in inches or tenths of an inch
39
Draft can be converted to pressure by multiplying inches of water column times ______.
0.036
40
Stack condensation in conventional boilers is most likely to occur?
In heating boiler installations where light loads and intermittent firing cause a cool stack condition.
41
The feedwater is heated to a maximum of _____ for reducing the amount of dissolved ______ and _______ in the feedwater.
210F; oxygen ; carbon dioxide
42
Boiler water pH typically should be between ?
10 and 11.5
43
ASME Symbol Stamps ``` S A E V M L PP H ```
``` S - Power Boiler A - Boiler Assembly E - Electric Boiler V - Safety Valve M - Miniature Boiler L - Locomotive Boiler PP - Pressure Piping H - Heating Boiler ```
44
A pressure reducing valve for make-up water on a low pressure boiler system should reduce the pressure to:
12-18psi
45
The aquastat starts and stops the burner based on different demands depending on boiler type. What is it for hot water? Steam?
Hot water - water temperature demand Steam - pressure control based on pressure demand
46
The pressure relief valve on a low pressure hot water boiler cannot exceed _____ or the MAWP designated on the boiler.
160 psi
47
One-pipe hot water heating system
One pipe to supply heated water from the boiler in a loop to return the water through the same pipe
48
One-pipe series system
Circulates water through one pipe that loops through each heating unit in order
49
One-pipe primary-secondary system
Use diverted valves to control water through a secondary loop to the heating unit
50
Two-pipe hot water heating system
One pipe to supply heated water from the boiler and one pipe to return water to the boiler
51
Two-pipe direct return system
Circulates supply water in the opposite direction of the circulation of the return water
52
Two-pipe reverse return system
Circulates supply water in the same direction as return water
53
Modulation
Accomplished by reducing the fuel and air input to the combustion process. Similar to changing the throttle setting on an internal combustion engine.
54
Turndown ratio
The ability of a boiler to reduce its heat output rate. Is the reciprocal of the lowest possible decimal percentage of full-heat output rate the boiler can maintain. I.e. - a boiler can maintain stable operation down to 20% of its maximum heat output rate, it would have a turndown ratio of 5:1.
55
Unconfined space
Must have a minimum of 50ft^3 volume per 1000 btu/hr. Of gas input rating of all gas-fired appliances in that space.
56
The NFPA code states that the minimum dimension of any rectangular supply air duct is ____ inches and any screening covering these openings cannot be finer than _____ inch mesh.
3 inches 1/4 inches
57
The number of blowdowns require is determined by?
Feedwater analysis
58
A ____ pump is a boiler accessory that draws condensate back from the system by producing a negative pressure on the condensate return lines
Vacuum
59
Oxygen in the boiler water causes
Pitting
60
A therm is equivalent to____ BTU
100,000
61
A ____ draft fan is located before the furnace
forced
62
Impurities that increase the surface tension of boiler water are removed with a ____ blowdown
Surface
63
The primary function of the water column on a low pressure boiler is to _____
Reduce water movement
64
The boiler vent is opened when ____
warming and draining the boiler
65
A low water condition requires _____ immediately
securing fuel to the burner
66
CO in the flue gas is an indication of _____ combustion
incomplete
67
T/F - Oxygen is required for teh combustion of fuel
True
68
T/F - A siphon is located between the boiler and steam pressure gauge to prevent water from entering the Bourdon Tube.
False
69
T/F - At the NOWL, the gauge glass is approximately half full.
True
70
T/F - A low water conditon in the boiler can cause overheating of the tubes.
True
71
T/F - City Water does not require treatment for use in a boiler
False
72
T/F - Steam traps, prevent the flow of condensate back to the deewater pump
False
73
T/F - Clogged fuel oil strainers cause high suction readings
True
74
T/F - Anthracite coal is hard coal
True
75
T/F - Draft is measrured with a manometer
True
76
T/F - Sludge is removed from teh boile with a surface blowdown
False
77
T/F - A dearator is a boiler water treatment accessory that heats feewater to the temperature of saturated steam within the pressure vessel.
True
78
T/F - All valves are closed when completing a dry lay-up
True
79
T/F - The boiler room log is used to record boiler operation events.
True
80
T/F - Forced circulation hot water heating systems are more common in a large building than natural circulation hot water heating systems.
True
81
T/F - The pressure reducing valve in a hot water heating system regulates the water pressure of water returning from heating units
False
82
T/F - A boiler is an open vessel in which water is transformed into steam under pressure by the application of heat
False
83
T/F - An HRT boiler is a watertube boiler
False
84
In a watertube boiler, the ____ passes through the tubes and the ____ passes across the ourside surface of the tubes.
water; combustion gases
85
The three most common fuels used in steam production are _____
natural gas, fuel oil, coal
86
T/F - In a natural draft furnace, the amount of draft, is affected by the height of the stack
True
87
Fuel oil grades commonly used in boilers are designated by No. ____ for the lightest grade of fueld oil through No.____ for the heavies grade of fuel oil.
2; 6
88
A boiler has quick - and slow-opening blowdown valves . The sequence used for the blowdown is_____
open quick-opening, open slow-opening, close slow-opening, close quick-opening
89
The most important boiler fitting is the _____
safety valve
90
The valve with the least amount of restriction is the _____ valve.
Gate
91
Steam boiler safety valves must be sized to prevent steam pressure from exceeding the MAWP by ____%
6%
92
Flame safeguard systems can monitor ______
pilot and main flame
93
Sensors used for flame detection in boilers include ____
lead sulfide cell, ultraviolet scanneer, thermocouple
94
A ___ blowdown is performed to remove sludge from the boiler
bottom
95
a pH level of 7.0 is an indication that the boiler water is _____
neutral, neither basic or acidic
96
At seal level, atmospheric pressure is approximately ___ psia
14.7
97
Specific gravity is the ratio of weight of a volume of a substance to the weight of the same volume of _____
water
98
Heat transfer can occur by ___
conduction, convection, radiation
99
Water weighs approximately ____ lb/gal
8.3
100
Boiler safety valves should be repaired by a ____
authorized safety valve repair company
101
T/F - MSDSs should only be available to supervisors and managers
False
102
T/F - The EPA does not regulate discharges of waste water from utility and industrial boiles
False
103
Foaming of boiler water from floating foreign matter causes an increase in ______
surface tension
104
Blowing down is most effective during a period when the steam output is _____
at a low rate
105
The water column must be located ___
at the normal operating water level
106
A boiler that is priming has ____
water carried over with the steam
107
If the low water alarm sounds ____
secure the fires
108
A feedwater pump can become steambound from _____
feedwater temperature too high
109
Infrared or ultraviolet rays are sensed by the _____
flame scanner
110
As the steam pressure increases in a boiler, there is a corresponding increase in the _____
boiler temperature of the water in the boiler
111
Complete combustion is _____
burning all the fuel with the theoretical amount of air
112
When testing a safety valve by hand on a low pressure steam boiler, the boiler must be at a minimum pressure of ____ before the try lever can be lifted without damaging the valve
5 psi
113
Draft in a boiler is a measured in _____
inches of water
114
A positive pressure before the furnace indicates ____ draft
forced
115
Preparation for a boiler inspection requires having the boiler _____
cool, opened and thoroughly cleaned
116
The firing rate of the burner is controlled by ____
modulating pressuretrol
117
A fan located between the breeching and the stack is a ___
induced draft fan
118
Class ____ fires are electrical fires, such as motor or transformer fires
C
119
A main steam stop valve would most likely be an ____
os&y gate valve
120
The evaporation of 34.5 pounds of water per hour from and at 212F is defined as ______
one boiler horsepower
121
A compound gauge is a pressure gauge that indicates _____
vacuum in inches of mercury or pressure in psi on the same gauge
122
When burning No. 6 fuel oil, a ____ is required.
Fuel oil heater
123
A ____ prevents the flow of boiler water back to the city water supply.
backflow preventer
124
The amount of british thermal units (BTU) per pound or gallon of fuel is the _____.
heating value
125
____ is the accumulation of minerals such as calcium and magnesium on boiler heating surfaces.
Scale
126
Tubes in a firetube boiler are mounted into the _____ located at the front and rear of the boiler.
tube sheet