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222 Cards in this Set

  • Front
  • Back

A low pressure steam boiler has a maximum allowable working pressure (MAWP) of up to ?

15 psi

The evaporation of 34.5 lb of water/he from and at a feedwater temperature of 212°F

One boiler horsepower

In a firetube boiler, the heat and the gasses of combustion pass ?

Through the tubes

A firetube boiler may be used _

In high or low pressure plants

Because of the large volume of water, the boiler to most likely cause a boiler explosion is?

A firetube

A horizontal return tubular (HRT) boiler is a _ boiler?


As stream pressure in a boiler increases, there is a corresponding increase in the?


A sudden drop in boiler stream pressure without a corresponding drop in boiler water temperature could result in a ?

Boiler explosion

The part of the boiler that has the heat and gases of combustion on one side and water on the other side is known as the ?

Heating surface

The comparison, or ratio, of heat supplied in fuel to heat absorbed by water is defined as _ efficiency?


Baffles stew designed to direct the gases of combustion so that they come into close contact with the _?

Boiler heating surface

The steam and drum of watertube boilers is dished (concave) to eliminate the need for ?


To increase the life of a furnace refractory, some watertube boilers are equipped with?


Vertical firetube boilers require?

High ceilings, less floor space, and the use of staybolts

In a watertube boiler, the heat and gases of combustion pass?

Around the tubes

The _ boiler has a large volume of water in relation to horsepower size?


Stays and braces are needed to prevent bulging in?

A furtive boiler (high or low pressures)

The _ boiler was developed to provide steam at higher pressures?


The mud drum is the lowest part of the waterside of a (n) _ boiler?


Boiler plates and stay bolts are subjected to _ stress?


Safety valve connections must be approved by the ?

American Society of Mechanical Engineers (ASME)

Boiler fittings are necessary for?

Safety and efficiency

The most important fitting on a boiler is the?

Safety valve

To prevent failure from pressure over the MAWP, all steam boilers must be equipped with at least one?

Safety valve

A safety valve will?

Prevent the boiler from exceeding it's MAWP

Safety valves are designed to ?

Pop open

Superheater safety valves are set to open _?

Before the main safety valves are set to open

When testing a safety valve by hand, there must be

at least 75% of the popping pressure

Any repairs to a safety valve should be done by the

safety valve manufacturer or manufacturer’s authorized representative

The setting or adjusting of a safety valve should only be done by the

qualified person who is familiar with the construction and operation of a safety valve

If it is necessary to test the relieving capacity of a safety valve

an accumulation test is put on the boiler

The relieving capacity of a safety valve is measured in

pounds of steam per hour capable of discharging under a given pressure

The main purpose of a water column is to

reduce turbulence in the gauge glass to get a more accurate reading of the water level in the boiler

Try cocks are

a secondary means of determining water level in a boiler

When replacing a broken gauge glass, the water level is checked by

using try cocks

The water column and gauge glass should usually be blown down

once a shift

A whistle valve is used to

warn the operator of high or low water

A steam pressure valve is calibrated in

pounds per square inch

A siphon protects the steam pressure gauge from

high temperature of steam

The pressure at the base of a vertical foot of water is

0.433 psi

The boiler vent is located at

highest part of the steam side of the boiler

The boiler vent is open when warming up a boiler until

there is 10 to 15 psi of steam pressure on the boiler

Steam separators work on the principle of

changing the direction of the steam flow

The dry pipe is located in the

upper part of the steam and water drum

Cyclone separators are used in

boilers equipped with superheaters

Saturated steam is steam at

its corresponding temperature and pressure

When steam is superheated the

temperature increases with no increase in pressure

Superheater tubes are protected from warping or burning out by

a continuous flow of steam

Soot should be
removed from boiler tubes for better heat transfer
Soot blowers are mainly found on
watertube boilers
Steam impinging on boiler tubes would

cut through the boiler tubes in a very short period of time

To ensure that moisture-free steam goes to the soot blower, the steam line to thesoot blower must come off the
highest part of the steam side of the drum
Boilers in battery equipped with manhole openings must have _ according to ASME code
two main steam stop valves
Main boiler stop valves must be_ valves
Os&Y gate
The ASME code will allow an automatic nonreturn valve to be used as a main steamstop valve. If one is used it must be

installed as close to the shell of the boiler as practical on the main steam line

The main stop steam stop valves should be gate valves because they

offer no restriction to the flow of steam

When the boiler is equipped with hand-operated, main steam stop valves, to cut the boiler in on the line, the steam pressure on the incoming boiler should be

slightly lower than line pressure

When a boiler is being inspected, the two main steam stop valves are
closed,locked, and tagged
During a boiler warm-up, to remove any condensate trapped between the two boiler stop valves the
free-blowing drain should be open
During normal usage, the boiler main steam line expands and contracts. To allow for this
expansion bends are used
According to the ASME code, boilers operating at 100 psi or over must have
two bottom blowdown valves
When a blowing down a boiler equipped with a quick-opening valve and a screw-typevalve, the quick-opening valve is
open first and closed last
If a quick-opening valve is used as a bottom blowdown valve, it must be located
between the boiler and the slow-opening (screw-type) valve

The maximum size of the bottom blowdown line and the surface blowdown line is


Bottom blowdown lines on a watertube boiler are located on the

mud drum

The most accurate means of deciding the frequency of blowdown of a boiler is determined by a

boiler water analysis

Surface tension on the water in the steam and water drum is increased by

impurities that float on the surface of the water

To protect sewer lines from the high temperature and high pressure coming from the boiler blowdown lines

blowdown tanks are used

A generating 20,000 lb boiler of steam/hr must be supplied with at least

20,00 lb of water/hr

Oxygen and other noncondensable gases are separated from the feedwater

in the open deaerator feedwater heater

The four systems required to operate a steam boiler are
steam,feedwater, fuel, and draft
In order to produce one pound of steam, it is necessary to evaporate
one lb of water

Steam that has lost its heat and has turned back into water is


Steam is extracted from the turbine after it has passed through some of the turbine stages to

be used for process work and heating

Water from an open deaerating feedwater heater flows

to the feedwater pump

A safe and efficient boiler plant should include pump(s)

one steam and one electric feedwater

A surface condenser has water

passed through tubes to cause steam to condense, causing a vacuum

On the feedwater line near the boiler is a check valve and a stop valve. The valve closest to the shell of the boiler is the _valve


On a boiler burning low pressure gas, the volume (amount) of gas burned is controlled by the

volume of air passing through the venturi tube

On the fuel oil system, the purpose of the duplex strainers on the suction line between the tank and fuel oil pump is to

allow one strainer to be cleaned without securing the boiler

A draft fan located between the boiler and chimney is used in a(n)_ draft system


When steam is superheated it has

more heat energy, thus producing more work

The vacuum on the exhaust side of the turbine

reduces back pressure and steam flow rate

The open feedwater heater is located

above the feedwater pump(s)

NO._ fuel oil must be heater in order to be pumped


Coal stokers were developed because

handfiring was inefficient in larger-sized boilers

Pulverized local coal has the consistency of talcum powder so that it

can come in closer contact with the oxygen for complete combustion

Draft is defined as a difference in pressure that causes

air or gases to flow

Air is mixed inside of the burner register in a(n) _ gas system

high pressure

Natural draft is produced by a(n)

difference in temperature of a column of gas inside the chimney from a column of air outside the chimney

Pulverized coal is burned in the _ in the furnace
Gas leaks should be located and repaired by a

gas company representative

Water weighs approximately _ lb/gal


The automatic city water makeup valve found on an open feedwater heater is used to

maintain a water level in the feedwater heater if there are insufficient condensate returns

The purpose of a feedwater regulator is to
maintain a consistent water level in the boiler
Feedwater regulator sensing elements are located
at the NOWL
The sequence of the three numbers found on the data plate attached to a reciprocating feedwater pump indicates the

diameter of steam piston,diameter of water piston, and the length of pump stroke

A(n)_ draft fan must be used to overcome resistance caused be gases of combustion leaving the boiler when an economizer is used
A reciprocating feedwater pump must have a safety valve located between the

pump and discharge valve

An economizer is used in large boiler plants to heat

feedwater using gases of combustion

The theory of operation of a centrifugal pump is that the centrifugal force of a rotating element
is converted into pressure
Centrifugal feedwater pumps can be started with their discharge valves
open or closed
A turbine feedwater pump differs from a centrifugal feedwater pump in that it is a
positive displacement pump
To protect the turbine pump from excessive pressure, a(n)

safety relief valve must be installed on the discharge line

The feedwater stop valve on the feedwater line is located closest to the shell of the boiler so that the
check valve can be repaired without taking the boiler off-line
Water temperature that is too high in the open feedwater heater could cause

the feedwater pump to become steam bound

Water temperature that is too low in the open feedwater heater could cause

oxygen pitting in the boiler

Aline desuperheater is typically used
when both superheated and saturated steam are needed, with a pressure-reducing station, and with feedwater addition to desuperheat the steam
Burning a fuel releases
heat energy
A clogged vent line fuel oil tank being filled with fuel oil could result in a
buildup,which would cause an oil pressure spill
A high suction line on a fuel oil tank is used when

signs of sludge and water are evident in the tank

The purpose of the fuel oil return line is to

circulate fuel oil during warm-up, return fuel oil that bypasses the burner, and return fuel oil from the relief valve

In both steam and air atomizing burners, atomization is accomplished by

live steam and air

In a low pressure gas burner, a _ shuts of the gas supply if a low water condition exits
manual reset valve
The pneumercator is used to
indicate gallons of fuel oil in the tank
An indication of a dirty fuel oil strainer would be _ across the strainer
a large pressure drop
Duplex strainers are found on _ of the fuel pump
both the suction and discharge sides
Fuel oil heaters must be used when burning No. _ fuel oil
Fuel oil heaters must be protected from excessive fuel oil pressure because they are located _ the fuel pumps
on the discharge side of
The rotary cup burner atomizes fuel oil using
a spinning cup and high velocity air
In a pressure atomizing burner, atomization is accomplished by

rotating, high pressure oil coming out of the plug or sprayer plate

A gas pressure regulator is used to control the
desired pressure at the burner
A solenoid valve is a direct-acting valve in the gas system and is used

as an automatic gas shutoff valve

To prevent caking and to dry the coal entering the pulverizer
warm air is used
Blowers are used in a high pressure gas system to
supply air for combustion
The air-to-gas ratio is maintained by a(n)

air damper, butterfly valve, and modulating motor and linkage

The amount of gas drawn into the air stream in a low pressure gas system is controlled by the
Venturi effect
Boilers are equipped with a combination gas/fuel oil burner for
more flexible operation
The underfeed stoker can burn
anthraciteor bituminous coal
Spreaderstokers burn coal
in suspension and on grates

To achieve complete combustion ina spreader stoker, air is introduced

under and over the fuel bed
The thickness of a fuel bed on a chain grate stoker is regulated by a coal
Pulverized coal burns
The volume of gas to the burner in a high pressure gas system in controlled by a _valve
In order to burn 1 lb of fuel, approximately _ lb of air are needed
Draft is measured in
inches or tenths of an inch of a vertical water column
Draft in the boiler is measured between two points such as the _ and _
atmosphere;inside the boiler setting
Pressure at the discharge side of a forced draft fan is _ atmospheric pressure
greater than
To reduce the heat loss of flue gases going to the chimney, boilers are equipped with
economizers and air heaters
The convection air heater employs a counterflow principle in which the gases ofcombustion
move up while the air goes down
Both air and flue gas temperatures are controlled by
the use of bypass dampers
If the temperature of air entering the heater gets too low, it will cause

condensation on the gas side of the air heater

Airheaters must be cleaned to ensure good heat transfer by
using soot blowers
Airheaters can most successfully be used in plants that
have a fairly constant steam load
If air supplied for combustion mixes with gases of combustion, it could lead to

a loss of air for combustion and lower boiler efficiency

A diaphragm draft gauge is calibrated in
inches of water
Mechanical draft is produced by the
power-driven fans
Mechanical draft can be classified as
forced or induced
The amount of draft available in a natural draft system is dependent on the

height of the chimney

The gases of combustion leaving a boiler that has a natural draft are controlled by
outlet dampers
The induced draft fan is located
between the boiler and the chimney
Mechanical draft is used when burning
fuel oil, coal, and gas
Large steam boilers that are equipped with air heaters and/or economizers must use
both forced and induced draft fans
When using mechanical draft, it is possible to
increase the rate of combustion
Draft pressure maintained at a constant pressure is called a _ draft system
The oldest form of draft used in a boiler is _ draft
Solid particles created in the combustion process are called
fly ash
The temperature at which fuel oil will give off a vapor that will ignite readily when exposed to an open flame is its _ point
In order to determine the heating value of coal in Btu per pound, the

ultimate analysis is used

The temperature at which fuel oil will give off a vapor that burns continuously is its _ point
Rank refers to the _ of the coal
degree of hardness
Grade refers to the _ of the coal
size,heating value, and ash content
A proximate analysis of coal provides information regarding its

moisture content, content of volatile matter, and fixed carbon and ash content

An ultimate analysis of coal provides information regarding
elements present in coal
Bituminous coal has a high _ content
Anthracite coal has a high _ content
When the temperature of fuel oil is raised, its viscosity
is lowered
The lowest temperature at which fuel oil will flow is its _ point
Fuel oil with a low flash point would be
dangerous to use
_coal is the type of coal most likely to have problems with spontaneous combustion when being stockpiled
A _fire extinguisher is the correct type to use on fuel oil fires
foam or dry chemical
Air that controls the rate of combustion is _ air
Air that is supplied to the burner that is more than the theoretical amount needed to burn fuel is _ air
_combustion is when all fuel is burned using only the theoretical amount of air supplied
_combustion is when all the fuel is burned using the minimal amount of excess air
Gases of combustion that cool on contact with the boiler heating surface before combustiobn is completed cause a(n)
formation of soot and smoke
Air needed for the combustion of fuel is made up of approximately _% oxygen and _%nitrogen
Soot and smoke are the result of _ combustion
_is a combustible found in fuel
carbon,sulfur, and hydrogen
Carbondioxide (Co2) in the flue gas indicates

complete combustion

Carbonmonoxide (CO) in the flue gas indicates
incomplete combustion
The Orsat has analyzer measures the percentage of _ in the flue gas

carbon dioxide, carbon monoxide,and oxygen

_is a type of combustion
complete,perfect, incomplete
No._ fuel oil must be heated to reach the required temperature for combustion
Higher number fuel oils produce _ lower numbered fuel oils
more Btu per gallon than
The heating value of a fuel is expressed in

British thermal units

The primary function of a combustion control is to ensure

safe and efficient boiler operation

The ON/OFF control system is usually found on

small package, firetube, and watertube boilers

The purpose of the boiler pressure control found in the ON/OFF control system is to
start and stop the burner on steam pressure demand
The ON/OFF pressure control must be connected to the

highest part of the steam side of the boiler

A steam siphon ensures that _ does not enter the boiler pressure controller
A mercury-tube pressure control will only be accurate when it is installed
invertical positon
The four elements that must be regulated in a combustion control system are

fuel supply; air supply; ratio of air to fuel; removal of combustion gases

The two scales found on the boiler pressure control are used to

set the operating steam pressure range of the boiler

The purpose of the boiler modulating pressure control is to

regulate the high and low firing rates of the burner

The modulating pressure control must be connected to the

highest part of the steam side of the boiler

The blower motor control continues to operate after fuel is shut off the burner during
The programmer in the ON/OFF control system is used to
control the burner firing cycle
To eliminate the danger of a furnace explosion during startup, the firing sequence must first allow for
a prepurge period
The purpose of the scanner is to prove
both the pilot and the main flame
The scanner must be installed on the front of the boiler to sight

both the pilot and the main frame

The flame sensor is sensitive to
infrared or ultraviolet rays
In the event of a flame failure, the programmer will

secure the fuel, purge the firebox, and then shut down

The positioning combustion control system used on older boilers cannot function without _ pressure
The metering combustion control system is sensitive to changes in

steam flow and pressure

Combustion air is controlled by
inlet damper, fan intake vanes, and the fan speed
Gases of combustion are pulled from the boiler by the
induced draft fan
The positioning combustion control system is sensitive to changes in the

steam header pressure

The most common type of pressure control used is the _ type
Pressure gauges are calibrated in pounds per
square inch
Absolute pressure is equal to

gauge pressure plus atmospheric pressure

A boiler steam-pressure gauge should have a range of

1.5 to 2 times the safety valve setting

The boiler steam-pressure gauge must be connected to the _ of the boiler

highest part of the steam side

The boiler steam-pressure gauge is protected from high temperatures by
a siphon
A primary reason for using thermocouples for measuring temperatures is

to take and read the readings for remote plants carefully

Vacuum gauges are calibrated in inches of _ atmospheric pressure
mercury below
Most thermometers used in a steam plant are calibrated in
degrees Fahrenheit
Thermocouples measure
A _reading can be read using a thermocouple

superheated steam, gases of combustion, and condensate return

Liquids in a tank may be measured from a remote location using a
Flowmeters measure the rate of flow of
avariety of fluids
The differential-pressure flow meter functions by receiving a difference ofpressure across a(n)
venture,orifice plate, and flow nozzle