| ABSOLUTE
PRESSURE |
Pressure
above zero pressure;
the sum of the gauge
and atmospheric
pressures.
|
| ACCUMULATOR |
(STEAM) A pressure
vessel containing
water and/or steam,
which is used to
store the heat of
steam for use at a
later period and at
some lower pressure.
|
| ACID
CLEANING |
The process of
cleaning the
interior surfaces of
steam generating
units by filling the
unit with dilute
acid accompanied by
an inhibitor to
prevent corrosion,
and subsequently
draining, washing
and neutralizing the
acid by a further
wash of alkaline
water.
|
| ACIDITY |
Represents the
amount of free
carbon dioxide,
mineral acids and
salts (especially
sulphates of iron
and aluminum) which
hydrolyze to give
hydrogen ions in
water and is
reported as
milliequivalents per
liter of acid, or
ppm acidity as
calcium carbonate,
or pH the measure of
hydrogen ions
concentration.
|
| ADIABATIC
FLAME TEMPERATURE |
The theoretical
temperature that
would be attained by
the products of
combustion provided
the entire chemical
energy of the fuel,
the sensible heat
content of the fuel
and combustion above
the datum
temperature were
transferred to the
products of
combustion. This
assumes: No heat
loss to surroundings
and no dissociation.
|
| AIR |
The mixture of
oxygen, nitrogen,
and other gases,
which with varying
amounts of water
vapor, forms the
atmosphere of the
earth.
|
| AIR
ATOMIZING OIL BURNER |
A burner for
firing oil in which
the oil is atomized
by compressed air,
which is forced into
and through one or
more streams of oil
which results in the
breaking of the oil
into a fine spray. |
| AIR
DEFICIENCY |
Insufficient air,
in an air-fuel
mixture, to supply
the oxygen required
for complete
oxidation of the
fuel. |
| AIR-FREE |
The descriptive
characteristic of a
substance from which
air has been
removed. |
| AIR-FUEL
RATIO |
The ratio of the
weight, or volume,
of air to fuel. |
| AIR
INFILTRATION |
The leakage of air
into a setting or
duct. |
| AIR,
SATURATED |
Air which contains
the maximum amount
of water vapor that
it can hold at its
temperature and
pressure. |
| AIR
VENT |
A valved opening
in the top of the
highest drum of a
boiler or pressure
vessel for venting
air. |
| ALARM |
A suitable horn,
bell, light or other
device which when
operated will give
notice of
malfunction or off
normal condition. |
| ALKALINITY |
Represents the
amount of
carbonates,
bicarbonates,
hydroxides and
silicates or
phosphates in the
water and is
reported as grains
per gallon, or ppm
as calcium
carbonate. |
| ALLOWABLE
WORKING PRESSURE |
See design
pressure. |
| AMBIENT
AIR |
The air that
surrounds the
equipment. The
standard ambient air
for performance
calculations is air
at 80 °F, 60%
relative humidity,
and a barometric
pressure of 29.921
in. Hg, giving a
specific humidity of
0.013 lb of water
vapor per lb of dry
air. |
| AMBIENT
TEMPERATURE |
The temperature of
the air surrounding
the equipment. |
| ANALYSIS |
Quantitative
determination of the
constituent parts. |
| ANALYSIS,
ULTIMATE |
Chemical analysis
of solid, liquid or
gaseous fuels. In
the case of coal or
coke, determination
of carbon, hydrogen,
sulfur, nitrogen,
oxygen, and ash. |
| AQUASTAT |
Water limit
temperature control,
a safety device
often used on
boilers. |
| ARRESTER |
A device to impede
the flow of large
dust particles or
sparks from a stack,
usually screening at
the top. |
| AS-FIRED
FUEL |
Fuel in the
condition as fed to
the fuel burning
equipment. |
| ASH |
The incombustible
inorganic matter in
the fuel. |
| ASH-FREE
BASIS |
The method of
reporting fuel
analysis, whereby
ash is deducted and
other constituents
are recalculated to
total 100%. |
| ASH
PIT |
A pit or hopper
located below a
furnace where refuse
is accumulated and
from which refuse is
removed at
intervals. |
| ASME |
The American
Society of
Mechanical
Engineers. |
| ASPIRATING
BURNER |
A burner in which
the fuel in a
gaseous or finely
divided form is
burned in
suspension, the air
for combustion being
supplied by bringing
into contact with
the fuel, air drawn
through one or more
openings by the
lower static
pressure created by
the velocity of the
fuel stream. |
| AS-RECEIVED
FUEL |
Fuel in the
condition as
received at the
plant. |
| ATMOSPHERIC
AIR |
Air under the
prevailing
atmospheric
conditions. |
| ATMOSPHERIC
PRESSURE |
The barometric
reading of pressure
exerted by the
atmosphere. at sea
level 14.7 lb per sq
in. or 29.92 in. of
mercury. |
| ATOMIZER |
A device by means
of which a liquid is
reduced to a very
fine spray. |
| AVAILABLE
DRAFT |
The draft which
may be utilized to
cause the flow of
air for combustion
or the flow of
products of
combustion. |
| AVAILABILITY
FACTOR |
The fraction of
time during which
the unit is in
operable condition. |
| AXIAL
FAN |
Consists of a
propeller or disc
type of wheel within
a cylinder that
discharges air
parallel to the axis
of the wheel. |
|
Back to
Index |
|
B
|
|
| BAFFLE |
A plate or wall
for deflecting gases
or liquids. |
| BAFFLE TILE |
A tile for
deflecting gases. |
| BAFFLE-TYPE
COLLECTOR |
A device in gas
paths utilizing
baffles so arranged
as to deflect dust
particles out of the
gas stream. |
| BAG
FILTER |
A device
containing one or
more cloth bags for
recovering particles
from the dust laden
gas or air which is
blown through it. |
| BAG-TYPE
COLLECTOR |
A filter in which
the cloth filtering
medium is made in
the form of
cylindrical bags. |
| BAROMETRIC
PRESSURE |
atmospheric
Pressure as
determined by a
barometer usually
expressed in inches
of mercury. |
| BASE
LOAD |
Base load is the
term applied to that
portion of a station
or boiler load that
is practically
constant for long
periods. |
| BEADED
TUBE END |
The rounded
exposed end of a
rolled tube when the
tube metal is formed
over against the
sheet in which the
tube is rolled. |
| BLIND
NIPPLE |
A nipple, or a
short piece of pipe
or tube, closed at
one end. |
| BLOWDOWN |
Boiler Water that
is removed from the
Boiler in order to
maintain the desired
concentration levels
of suspended and
dissolved solids in
the Boiler and
removal of sludge. |
| BLOWDOWN
SAFETY VALVE |
The difference
between the pressure
at which a safety
valve opens and at
which it closes. |
| BLOWDOWN
VALVE |
A valve generally
used to continuously
regulate
concentration of
solids in the
boiler, not a drain
valve. See continuous
blowdown |
| BLOW-OFF
VALVE |
A specially
designed, manually
operated, valve that
connects to the
Boiler for the
purpose of reducing
the concentration of
solids in the Boiler
or for draining
purposes. (often
called bottom
blowdown.) |
| BLOWER |
A fan used to
force air under
pressure. |
| BOILER |
A closed vessel in
which Water is
heated, steam is
generated, steam is
superheated, or any
combination thereof,
under Pressure or
vacuum by the
application of heat
from combustible
fuels, electricity
or nuclear energy. |
| BOILER
EFFICIENCY |
The term boiler
efficiency is often
substituted for
combustion or
thermal efficiency.
True boiler
efficiency is the
measure of
fuel-to-steam
efficiency. |
| BOILER
HORSEPOWER |
The evaporation of
34-1/2 lbs of water
per hour from a
temperature of 212
°F into dry
saturated steam at
the same
temperature.
Equivalent to 33,475
Btu/hr. |
| BOILER
RATING |
The heating
capacity of a boiler
expressed in boiler
horsepower,
Btu/hour, or pounds
of steam/hour. |
| BOILER
SHELL |
The outer
cylindrical portion
of a Pressure
vessel. |
| BOILER
WATER |
A term construed
to mean a
representative
sample of the
circulating boiler
water, after the
generated steam has
been separated and
before the incoming
feed water or added
chemical becomes
mixed with it so
that its composition
is affected. |
| BOILING |
The conversion of
a liquid into vapor
with the formation
of bubbles. |
| BOILING
OUT |
The boiling of
highly alkaline
water in boiler
pressure parts for
the removal of oils,
greases, etc. |
| BOOSTER
FAN |
A device for
increasing the
Pressure or flow of
a gas. |
| BREECHING |
A duct that
transports the
products of
combustion between
parts of a steam
generating unit or
to the stack. |
| BRIDGEWALL |
A wall in a
furnace over which
the products of
combustion pass. |
| BRITISH
THERMAL UNIT |
(Btu) A Btu is
essentially 252
calories. The mean
British Thermal Unit
is 1/180 of the heat
required to raise
the temperature of 1
lb of water from 32
°F to 212 °F at a
constant |
| BUCKSTAY |
A structural
member placed
against a furnace or
boiler wall to
restrain the motion
of the wall. |
| BUNKER
C OIL |
Residual fuel oil
of high viscosity
commonly used in
marine and
stationary steam
power plants. (No. 6
fuel oil) |
| BURNER |
A device for the
introduction of fuel
and air into a
furnace at the
desired velocities,
turbulence and
concentration. |
| BURNER
WINDBOX |
A plenum chamber
around a burner that
maintains an air
pressure sufficient
for proper
distribution and
discharge of
secondary air. |
| BURNER
WINDBOX PRESSURE |
The air pressure
maintained in the
windbox or plenum
chamber measured
above atmospheric
pressure. |
| BY-PASS |
A passage for a
fluid, permitting a
portion of the fluid
to flow around its
normal pass flow
channel. |
|
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Index |
|
C
|
|
| C |
Carbon element,
the principal
combustible
constituent of all
fuels. |
| CaCO3 |
Calcium Carbonate. |
| CALORIE |
The mean calorie
is 1/100 of the heat
required to raise
the temperature of 1
gram of water from
Zero C to 100 °C at
a constant
atmospheric
pressure. It is
about equal to the
quantity of heat
required to raise
one gram of water 1
°C. Another
definition is: A
calorie is 3600/860
joules. |
| CALORIMETER |
Apparatus for
determining the
calorific value of a
fuel. |
| CAPACITY
FACTOR |
The ratio of the
average load carried
to the maximum
design capacity. |
| CARBON |
Element. The
principal
combustible
constituent of all
fuels. |
| CARRYOVER |
The chemical
solids and liquid
entrained with the
steam from a boiler. |
| CASING |
A covering of
sheets of metal or
other material such
as fire resistant
composition board
used to enclose all
or a portion of a
steam generating
unit. |
| CENTRAL
STATION |
A power plant or
steam heating plant
that generates power
or steam. |
| CENTRIFUGAL
FAN |
Consists of a fan
rotor or wheel
within a housing
that discharges air
at a right angle to
the axis of the
wheel. |
| CHEMICAL
ANALYSIS |
Determination of
the principal
chemical
constituents. |
| CHEMICAL
FEED PIPE |
A pipe inside a
boiler drum through
which chemicals for
treating the boiler
water are
introduced. |
| CHIMNEY |
A brick, metal or
concrete stack. |
| CIRCULATION |
The movement of
water and steam
within a steam
generating unit. |
| CIRCULATION
RATIO |
The ratio of water
entering a circuit
to the steam
generated by that
passes that circuit
in a unit of time. |
| CIRCULATOR |
A pipe or tube to
pass steam or water
between upper boiler
drums usually
located where the
heat absorption is
low. Also used to
apply to tubes
connecting headers
of horizontal water
tube boilers with
drums. |
| CLEANOUT
DOOR |
A door placed so
that accumulated
refuse may be
removed room a
boiler setting. |
| CO |
Carbon monoxide. |
| CO2 |
Carbon dioxide. |
| COLLECTOR |
A device used for
removing gas borne
solids from flue
gas. |
| COLLOID |
A finely divided
organic substance
which tends to
inhibit the
formation of dense
scale and results in
the deposition of
sludge, or causes it
to remain in
suspension, so that
it may be blown from
the boiler. |
| COMBUSTIBLE
LOSS |
The loss
representing the
unliberated thermal
energy occasioned by
failure to oxidize
completely some of
the combustible
matter in the fuel. |
| COMBUSTIBLES |
The heat producing
constituents of a
fuel. |
| COMBUSTION |
The rapid chemical
combination of
oxygen with the
combustible elements
of a fuel resulting
in the release of
heat. |
| COMBUSTION
AIR |
Air used in the
combustion process.
Air contains oxygen
which is required to
combust fuel. |
| COMBUSTION
CHAMBER |
See Furnace |
| COMBUSTION
EFFICIENCY |
The effectiveness
of the burner to
completely burn the
fuel. A well
designed burner will
operate with as
little as 10 to 20%
excess air, while
converting all
combustibles in the
fuel to useful
energy. |
| COMPLETE
COMBUSTION |
The
complete oxidation
of all the
combustible
constituents of a
fuel. |
| CONCENTRATION |
(1) The weight of
solids contained in
a unit weight of
boiler or feed
water. (2) The
number of times that
the dissolved solids
have increased from
the original amount
in the feedwater to
that in the boiler
water due to
evaporation in
generating steam. |
| CONDENSATE |
Condensed water
resulting from the
removal of latent
heat from steam. |
| CONDUCTION |
The transmission
of heat through and
by means of matter
unaccompanied by any
obvious motion of
the matter. |
| CONDUCTIVITY |
(1) A material
property relating
heat flux (heat
transferred per unit
area per unit time)
to a temperature
difference. In
American units, it
is typically defined
as the amount of
heat (Btu)
transmitted in one
hour through one
square foot of
material 1 inch
thick, with a
temperature
difference of 1°F
between the two
surfaces of the
material. (2) The
property of a water
sample to transmit
electric current
under a set of
standard conditions.
Usually expressed as
microhms
conductance. |
| CONTINUOUS
BLOWDOWN |
The uninterrupted
removal of
concentrated boiler
water from a boiler
to control total
solids concentration
in the remaining
water. |
| CONTROL |
Any manual or
automatic device for
the regulation of a
machine to keep it
at normal operation.
If automatic, the
device is motivated
by variations in
temperature,
pressure, water
level, time, light,
or other influences. |
| CONTROL
VALVE |
A valve used to
control the flow of
air, gas, water,
steam or other
substance. |
| CONVECTION |
The transmission
of heat by the
circulation of a
liquid or gas. It
may be natural, with
the circulation
caused by buoyancy
affects due to
temperature
differences, or
forced with
circulation caused
by a mechanical
device such as a fan
or pump. |
| CORROSION |
The wasting away
of metal due to
chemical action. In
a boiler, usually
caused by the
presence of O2, CO2,
or an acid. |
| CROWN
SHEET |
In a firebox
boiler, the plate
forming the top of
the furnace. |
| CRUDE
OIL |
Unrefined
petroleum. |
| CSD-1 |
Abbreviation for
the ASME standard
for Controls and
Safety Devices. |
|
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Index |
|
D
|
|
| DAMPER |
A device for
introducing a
variable Pressure
drop in a system
used for regulating
The volumetric flow
of a gas, such as
air. |
| DAVIT |
The structure on
large firetube
boilers from which
the front and rear
doors are suspended
when opened. |
| DEAERATION |
Removal of air and
gases from boiler
feed water prior to
its introduction to
a boiler. |
| DEGASIFICATION |
Removal of gases
from samples of
steam taken for
purity test. Removal
of CO2 from water as
in the ion exchange
method of softening. |
| DELAYED
COMBUSTION |
A continuation of
combustion beyond
the furnace. (See
also Secondary
Combustion.) |
| DESIGN
LOAD |
The load for which
a steam generating
unit is designed,
considered the
maximum load to be
carried. |
| DESIGN
PRESSURE |
The pressure used
in the design of a
boiler for the
purpose of
calculating the
minimum permissible
thickness or
physical
characteristics of
the different parts
of the boiler. |
| DESIGN
STEAM TEMPERATURE |
The temperature of
steam for which a
boiler is designed. |
| DEW
POINT |
The temperature at
which condensation
starts. |
| DISENGAGING
SURFACE |
The surface of the
boiler water from
which steam is
released. |
| DISSOCIATION |
The process by
which a chemical
compound breaks down
into simpler
constituents, as do
CO2 and H2O at high
temperature. |
| DISSOLVED
SOLID |
Those solids in
water which are in
solution. |
| DISTILLATE
FUELS |
Liquid fuels
distilled usually
from crude
petroleum. |
| DISTILLATION |
Vaporization of a
substance with
subsequent recovery
of the vapor by
condensation. Often
used in less precise
sense to refer to
vaporization of
volatile
constituents of a
fuel without
subsequent
condensation. |
| DISTILLED
WATER |
Water produced by
vaporization and
condensation with a
resulting higher
purity. |
| DOWNCOMER |
A tube or pipe in
a boiler or
waterwall
circulating system
through which fluid
flows downward. |
| DOWNTIME |
Amount of time a
piece of equipment
is not operational. |
| DRAFT |
The difference
between atmospheric
pressure and some
lower pressure
existing in the
furnace stack or gas
passages of a steam
generating unit. |
| DRAFT
DIFFERENTIAL |
The difference in
static Pressure
between two points
in a system. |
| DRAFT
GAUGE |
A device for
measuring draft,
usually in inches of
water. |
| DRAIN |
A valved
connection at the
lowest point for the
removal of all water
from the pressure
parts. |
| DRUM |
A cylindrical
shell closed at both
ends designed to
withstand internal
pressure. |
| DRY
AIR |
Air with which no
water vapor is
mixed. This term is
used comparatively,
since in nature
there is always some
water vapor included
in air, and such
water vapor, being a
gas, is dry. |
| DRYBACK
BOILER |
Firetube boiler
with a refractory
lined back door.
Door opens to allow
maintenance and/or
inspection. |
| DRY
GAS |
Gas containing no
water vapor. |
| DRY-GAS
LOSS |
The loss
representing the
difference between
the heat content of
the dry exhaust
gases and their heat
content at the
temperature of
ambient air. |
| DRY
STEAM |
Steam containing
no moisture.
Commercially dry
steam containing not
more than one half
of one percent
moisture. |
| DUCT |
A passage for air
or gas flow. |
|
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Index |
|
E
|
|
| ECONOMIZER |
Utilizes waste
heat by transferring
heat from flue gases
to warm incoming
feedwater. |
| EDR |
Equivalent direct
radiation is the
rate of heat
transfer from a
radiator or
convector. It is
equivalent to the
square feet of
surface area
necessary to
transfer heat at the
same rate at which
it is produced by a
generator. A single
boiler horsepower
equals 140 ft2 EDR. |
| EFFICIENCY |
The ratio of
output to input. See
also Combustion,
Fuel-to-Steam and
Thermal Efficiency. |
| EJECTOR |
A device which
utilizes the kinetic
energy in a jet of
water or other fluid
to remove a fluid or
fluent material from
tanks or hoppers. |
| ELECTRIC
BOILER |
A boiler in which
electric energy is
used as the source
of heat. |
| ELECTROSTATIC
PRECIPITATOR |
A device for
collecting dust,
mist or fume from a
gas stream, by
placing an
electrical
charge on the
particle and
removing that
particle onto a
collecting
electrode. |
| ENTRAINMENT |
The conveying of
particles of Water
or solids from the
Boiler Water by the
steam. |
| EQUALIZER |
Connections
between parts of a
boiler to equalize
pressures. |
| EQUIVALENT
EVAPORATION |
Evaporation
expressed in pounds
of water evaporated
from a temperature
of 212 °F to dry
saturated steam at
212 °F. |
| EVAPORATION |
The change of
state from a liquid
to a vapor. |
| EVAPORATION
RATE |
The number of
pounds of water that
is evaporated in a
unit of time. |
| EXCESS
AIR |
Air supplied for
combustion in excess
of that
theoretically
required for
complete oxidation. |
| EXPANSION
JOINT |
The joint to
permit movement due
to expansion without
undue stress. |
| EXPLOSION
DOOR |
A door in a
furnace or boiler
setting that is
designed to be
opened by a
pre-determined gas
pressure. |
| EXTERNAL
TREATMENT |
Treatment of
boiler feed water
prior to its
introduction into
the boiler. |
|
Back to
Index |
|
F
|
|
| FAN |
A machine
consisting of a
rotor and housing
for moving air or
gases at relatively
low pressure
differentials. |
| FAN
PERFORMANCE |
A measure of fan
operation in terms
of volume, total
pressures, static
pressures, speed,
power input,
mechanical and
static efficiency,
at a stated air
density. |
| FAN
PERFORMANCE CURVES |
The graphical
presentation of
total pressure,
static pressure,
power input,
mechanical and
static efficiency as
ordinates and the
range of volumes as
abscissa, all at
constant speed and
air density. |
| FEED
PUMP |
A pump that
supplies water to a
boiler. |
| FEEDWATER |
Water introduced
into a boiler during
operation. It
includes make-up and
return condensate. |
| FEEDWATER
TREATMENT |
The treatment of
boiler feed water by
the addition of
chemicals to prevent
the formation of
scale or to
eliminate other
objectionable
characteristics. |
| FGR |
Flue Gas
Recirculation or the
recirculation of
flue gas with
combustion air to
reduce NOx
emissions. |
| FILTER |
Porous material
through which fluids
or fluid - and solid
mixtures are passed
to separate matter
held in suspension. |
| FIN |
A fin is an
extended surface, a
solid, experiencing
energy transfer by
conduction within
its boundaries, as
well as energy
transfer with its
surroundings by
convection and/or
radiation, used to
enhance heat
transfer by
increasing surface
area. |
| FIN
TUBE |
A tube with one or
more fins. |
| FIRED
PRESSURE VESSEL |
A vessel
containing a fluid
under pressure
exposed to heat from
the combustion of
fuel. |
| FIRETUBE |
A type of boiler
design in which
combustion gases
flow inside the
tubes and water
flows outside the
tubes. |
| FIRING
RATE CONTROL |
A pressure
temperature or flow
controller which
controls the firing
rate of a burner
according to the
deviation from
pressure or
temperature set
point. The system
may be arranged to
operate the burner
on-off, high-low or
in proportion to
load demand. |
| FIXED
CARBON |
The carbonaceous
residue less the ash
remaining in the
test container after
the volatile matter
has been driven off
in making the
proximate analysis
of a solid fuel. |
| FLAME |
A luminous body of
burning gas or
vapor. |
| FLAME
DETECTOR |
A device which
indicates if a fuel
(liquid, gaseous, or
pulverized) is
burning, or if
ignition has been
lost. The indication
may be transmitted
to a signal or to a
control system. |
| FLAME
PROPAGATION RATE |
Speed of travel of
ignition through a
combustible mixture. |
| FLAME
SAFEGUARD |
A control that
sequences the burner
through several
stages of operation
to provide proper
air purge, ignition,
normal operation,
and shutdown for
safe operation. |
| FLAMMABILITY |
Susceptibility to
combustion. |
| FLASHING |
The process of
producing steam by
discharging water
into a region of
pressure lower than
the saturation
pressure that
corresponds to the
water temperature. |
| FLASH
POINT |
The lowest
temperature at
which, under
specified
conditions, fuel oil
gives off enough
vapor to flash into
a momentary flame
when ignited. |
| FLUE |
A passage for
products of
combustion. |
| FLUE
GAS |
The gaseous
product of
combustion in the
flue to the stack. |
| FOAMING |
The continuous
formation of bubbles
which have
sufficiently high
surface tension to
remain as bubbles
beyond the
disengaging surface. |
| FORCED
CIRCULATION |
The circulation of
water in a boiler by
mechanical means
external to the
boiler. |
| FORCED-DRAFT
FAN |
A fan supplying
air under pressure
to the fuel burning
equipment. |
| FOULING |
The accumulation
of refuse in gas
passages or on heat
absorbing surfaces
which results in
undesirable
restriction to the
flow of gas or heat. |
| FM |
Factory Mutual. |
| FREE
ASH |
Ash which is not
included in the
fixed ash. |
| FUEL |
A substance
containing
combustible used for
generating heat. |
| FUEL-AIR
MIXTURE |
Mixture of fuel
and air. |
| FUEL-AIR
RatIO |
The ratio of the
weight, or volume,
of fuel to air. |
| FUEL
OIL |
A liquid fuel
derived from
petroleum or coal. |
| FUEL-TO-STEAM
EFFICIENCY |
The ratio of heat
added to boiler
feedwater to produce
the output steam to
the amount of energy
inputted with fuel. |
| FURNACE |
An enclosed space
provided for the
combustion of fuel. |
| FURNACE
PRESSURE |
Pressure occurring
inside the
combustion chamber;
positive if greater
than atmospheric,
negative if less
than atmospheric,
and neutral if equal
to atmospheric. |
| FURNACE
VOLUME |
The cubic contents
of the furnace or
combustion chamber. |
| FUSIBLE
PLUG |
A hollowed
threaded plug having
the hollowed portion
filled with a low
melting point
material. |
|
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Index |
|
G
|
|
| GAS
ANALYSIS |
The determination
of the constituents
of a gaseous
mixture. |
| GAS
BURNER |
A burner that uses
gas or fuel. |
| GAS
PRESSURE REGULATOR |
A spring loaded,
dead weighted or
pressure balanced
device which will
maintain the gas
pressure to the
burner supply line. |
| GAUGE
COCK |
A valve attached
to a Water column or
drum for checking
Water level. |
| GAUGE
GLASS |
The transparent
part of a water
gauge assembly
connected directly
or through a water
column to the
boiler, below and
above the water
line, to indicate
the water level in a
boiler. |
| GAUGE
PRESSURE |
The pressure above
atmospheric
pressure. |
| GRADE |
Oil classification
according to
quality, generally
based on ASTM
specifications. |
| GRAINS
PER CU-FT |
The term for
expressing dust
loading in weight
per unit of gas
volume (7000 grains
equals one pound). |
| GRAINS
(WATER) |
A unit of measure
commonly used in
water analysis for
the measurement of
impurities in water
(17.1 grains = 1
part per million -
ppm). |
| GRAVITY |
Weight index of
fuels: liquid,
petroleum products
expressed either as
specific, Baume or
A.P.I. (American
Petroleum Institute)
gravity; weight
index of gaseous
fuels as specific
gravity related to
air under specified
conditions; or
weight index of
solid |
|
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Index |
|
H
|
|
| HANDHOLE |
An access opening
in a pressure part
usually not
exceeding 6inches in
its longest
dimension. |
| HANDHOLE
COVER |
A handhole
closure. |
| HARDNESS |
A measure of the
amount of calcium
and magnesium salts
in water. Usually
expressed as grains
per gallon or ppm as
CaCO3. |
| HARD
WATER |
Water which
contains calcium or
magnesium in an
amount which require
an excessive amount
of soap to form a
lather. |
| HEAT
AVAILABLE |
The thermal energy
above a fixed datum
that is capable of
being absorbed for
useful work. |
| HEAT
BALANCE |
An accounting of
the distribution of
the heat input,
output and losses. |
| HEAT
EXCHANGER |
A vessel in which
heat is transferred
from one medium to
another. |
| HEAT
RELEAS |
Rate that
describes the heat
available per square
foot of
heat-absorbing
surface in the
furnace or per cubic
foot of volume. |
| HEATING
SURFACE |
Those surfaces
which are exposed to
products of
combustion on one
side and water on
the other. This
surface is measured
on the side
receiving the heat. |
| HEATING
VALUE |
The quantity of
heat released by a
fuel through
complete combustion.
It is commonly
expressed in Btu per
lb, per gallon, or
cu-ft. |
| HIGH
GAS PRESSURE CONTROL |
A control to stop
the burner if the
gas Pressure is too
high. |
| HIGH
OIL TEMPERATURE
CONTROL |
A control to stop
the burner if the
Oil temperature is
too high. |
| HYDROCARBON |
A chemical
compound of hydrogen
and carbon. |
| HYDROSTATIC
TEST |
A strength and
tightness test of a
closed pressure
vessel by water
pressure. |
|
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Index |
|
I
|
|
| IGNITION |
The initiation of
combustion. |
| IGNITION
TEMPERATURE |
Lowest temperature
of a fuel at which
combustion becomes
self-sustaining. |
| ILLUMINANTS |
Light Oil or coal
compounds that
readily burn with a
luminous flame, such
as ethylene,
propylene and
benzene. |
| INCOMPLETE
COMBUSTION |
The partial
oxidation of the
combustible
constituents of a
fuel. |
| INDUCED
DRAFT FAN |
A fan exhausting
hot gases from the
heat absorbing
equipment. |
| INERT
GASEOUS CONSTITUENTS |
Incombustible
gases such as
nitrogen which may
be present in a
fuel. |
| INHIBITOR |
A substance which
selectively retards
a chemical action.
an example in Boiler
work is the use of
an inhibitor, when
using acid to remove
scale, to prevent
the acid from
attacking the Boiler
metal. |
| INJECTOR |
A device utilizing
a steam jet to
entrain and deliver
feed water into a
boiler. |
| INSULATION |
A material of low
thermal conductivity
used to reduce heat
losses. |
| INTEGRAL
BLOWER |
A blower built as
an integral part of
a device to supply
air thereto. |
| INTEGRAL-BLOWER
BURNER |
A burner of which
the blower is an
integral part. |
| INTERLOCK |
A device to prove
the physical state
of a required
condition, and to
furnish that proof
to the primary
safety control
circuit. |
| INTERMITTENT
BLOWDOWN |
The blowing down
of Boiler Water at
intervals. |
| INTERNAL
TREATMENT |
The treatment of
Boiler Water by
introducing
chemicals directly
into the boiler. |
| ION |
A charged atom or
radical which may be
positive or
negative. |
| IRI |
Industrial Risk
Insurers. |
|
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Index |
|
J
|
|
|
K
|
|
|
L
|
|
| LAGGING |
A light gauge
steel covering used
over a boiler,
usually combined
with insulation, to
provide a low
temperature outer
surface. |
| LEAKAGE |
The uncontrolled
quantity of fluid
which enters or
leaves through the
enclosure of air or
gas passages. |
| LIBERATION |
See Heat Release. |
| LIMIT
CONTROL |
A switching device
that completes or
breaks an electrical
circuit at
predetermined
pressures or
temperatures. Also
known as an
interlock. See
interlock. |
| LINING |
The material used
on the furnace side
of a furnace wall.
It is usually of
high grade
refractory tile or
brick or plastic
refractory material. |
| LOAD |
The rate of output
required; also the
weight carried. |
| LOAD
FACTOR |
The ratio of the
average load in a
given period to the
maximum load carried
during that period. |
| LOW
GAS PRESSURE CONTROL |
A control to stop
the burner if gas
pressure is too low. |
| LOW
OIL TEMPERATURE
CONTROL |
(Cold Oil Switch)
a control to prevent
burner operation if
the temperature of
the Oil is too low. |
| LOW
WATER CUTOFF |
Safety device that
shuts off the
Boiler/burner in the
event of low Water,
preventing Pressure
vessel failure. |
| LUG |
Any projection,
like an ear, used
for supporting or
grasping. |
|
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Index |
|
M
|
|
| MAKE-UP |
The Water added to
Boiler feed to
compensate for that
lost through
exhaust, blowdown,
leakage, etc. |
| MANHOLE |
The opening in a
pressure vessel of
sufficient size to
permit a man to
enter. |
| MANIFOLD |
A pipe or header
for collection of a
fluid from, or the
distribution of a
fluid to a number of
pipes or tubes. |
| MANUAL
GAS SHUTOFF VALVE |
A manually
operated valve in a
gas line for the
purpose of
completely turning
on or shutting off
the gas supply. |
| MANUFACTURED
GAS |
Fuel gas
manufactured from
coal, Oil, etc., as
differentiated from
natural gas. |
| MAXIMUM
ALLOWABLE WORKING
PRESSURE |
The maximum gauge
pressure permissible
in a completed
boiler. The MAWP of
the completed boiler
shall be less than
or equal to the
lowest design
pressure determined
for any of its
parts. This pressure
is based upon either
proof tests or
calculations for
every pressure part
of the boiler using
nominal thickness
exclusive of
allowances for
corrosion and
thickness required
for loadings other
than pressure. It is
the basis for the
pressure setting of
the pressure
relieving devices
protecting the
boiler. |
| MAXIMUM
CONTINUOUS LOAD |
The maximum load
which can be
maintained for a
specified period. |
| MAXIMUM
INSTANTANEOUS DEMAND |
The sudden load
demand on a Boiler
beyond which an
unbalanced condition
may be established
in the boilers
internal flow
pattern and/or
surface release
conditions. |
| MECHANICAL
ATOMIZING OIL BURNER |
A
burner
which uses the
Pressure of the Oil
for atomization. |
| MECHANICAL
DRAFT |
The negative
pressure created by
mechanical means. |
| MICRON |
One millionth of a
meter, or 0.000039
in. or 1/25400 in.
The diameter of dust
particles is often
expressed in
microns. |
| MINIATURE
BOILER |
Fire pressure
vessels which do not
exceed the following
limits: 16 in.
inside diameter of
shell; 42 in.,
overall length to
outside of heads at
center; 20 sq ft
water heating
surface; or 100 psi
maximum allowable
working pressure. |
| MMBtu |
Millions of Btus
(British Thermal
Units). |
| MOISTURE |
Water in the
liquid or vapor
phase. |
| MOISTURE
IN STEAM |
Particles of Water
carried in steam,
expressed as the
percentage by
weight. |
| MOISTURE
LOSS |
The Boiler flue
gas loss
representing the
difference in the
heat content of the
moisture in the exit
gases and that at
the temperature of
the ambient air. |
| MULTIFUEL
BURNER |
A burner by means
of which more than
one fuel can be
burned. |
| MULTIPORT
BURNER |
A burner having a
number of nozzles
from which fuel and
air are discharged. |
|
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Index |
|
N
|
|
| NATURAL
CIRCULATION |
The circulation of
water in a boiler
caused by
differences in
density. |
| NATURAL
GAS |
Gaseous fuel
occurring in nature. |
| NET
POSITIVE SUCTION
HEAD (NPSH) |
The liquid
Pressure that exists
at the suction end
of a pump. if the
NPSH is
insufficient, The
pump can cavitate. |
| Nox |
Abbreviation for
all of the family of
oxides of nitrogen. |
| NOZZLE |
A short flanged or
welded neck
connection on a drum
or shell for the
outlet or inlet of
fluids; also a
projecting spout
through which a
fluid flows. |
|
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Index |
|
O
|
|
| OIL
BURNER |
A burner for
firing oil. |
| OIL
HEATING AND PUMPING
SET |
A group of
apparatus consisting
of a heater for
raising the
temperature of the
Oil to produce the
desired viscosity,
and a pump for
delivering the Oil
at the desired
pressure. |
| OPERATING
CONTROL |
A control to start
and stop the burner
- must be in
addition to the high
limit control. |
| OPERATING
PRESSURE |
The Pressure at
which a Boiler is
operated. |
| ORGANIC
MATTER |
Compounds
containing carbon
often derived from
living organisms. |
| ORIFICE |
(1) The opening
from the whirling
chamber of a
mechanical atomizer
or the mixing
chamber of a steam
atomizer through
which the liquid
fuel is discharged.
(2) A calibrated
opening in a plate,
inserted in a gas
stream for measure
velocity of flow. |
| ORSAT |
A gas-analysis
apparatus in which
certain Gaseous
constituents are
measured by
absorption in
separate chemical
solution. |
| OVERPRESSURE |
Minimum operating
pressure of a hot
water boiler
sufficient to
prevent the water
from steaming. |
| OXIDATION |
Chemical
combination with
oxygen. |
| OXIDIZING
ATMOSPHERE |
An atmosphere
which tends to
promote the
oxidation of
immersed materials. |
| OXYGEN
ATTACK |
Corrosion or
pitting in a Boiler
caused by oxygen. |
|
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Index |
|
P
|
|
| PACKAGED
BOILER |
A Boiler supplied
with all of its
components - burner,
controls and
auxiliary equipment,
designed as a single
engineered package,
and ready for
on-site
installation. |
| PACKAGED
STEAM GENERATOR |
See Packaged
boiler. |
| PARTICLE
SIZE |
A measure of dust
size, expressed in
microns or per cent
passing through a
standard mesh
screen. pass - a
confined passageway,
containing heating
surface, through
which a fluid flows
in essentially one
direction. |
| PERFECT
COMBUSTION |
The complete
oxidation of all the
combustible
constituents of a
fuel, utilizing all
the oxygen supplied. |
| PETROLEUM |
Naturally
occurring mineral
Oil consisting
predominately of
hydrocarbons. |
| pH |
The hydrogen ion
concentration of a
water to denote
Acidity or
Alkalinity. A pH of
7 is neutral. A pH
above 7 denotes
alkalinity while one
below 7 denotes
acidity. This pH
number is the
negative exponent of
10 representing
hydrogen ion
concentration in |
| PILOT |
A flame
which is utilized to
ignite the fuel at
the main burner or
burners. |
| PITOT
TUBE |
An instrument
which will register
total Pressure and
static Pressure in a
gas stream, used to
determine its
velocity. |
| PITTING |
A concentrated
attack by oxygen or
other corrosive
chemicals in a
Boiler, producing a
localized depression
in the metal
surface. |
| PORT |
An opening through
which fluid passes. |
| POST
PURGE |
A method of
scavenging the
furnace and boiler
passes to remove all
combustible gases
after flame failure
controls have sensed
pilot and main
burner shutdown and
safety shut-off
valves are closed. |
| ppm |
Abbreviation for
parts per million.
used in chemical
determinations as
one part per million
parts by weight. |
| PRECIPITATE |
To separate
materials from a
solution by the
formation of
insoluble matter by
chemical reaction.
The material which
is removed. |
| PRECIPITATION |
The removal of
solid or liquid
particles from a
fluid. |
| PREHEATED
AIR |
Air at a
temperature
exceeding that of
the ambient air.
PRESSURE - Force per
unit of area. |
| PRESSURE
DROP |
The difference in
pressure between two
points in a system,
caused by resistance
to flow. |
| PRESSURE
VESSEL |
A closed vessel or
container designed
to confine a fluid
at a pressure above
atmospheric. |
| PRIMARY
AIR |
Air introduced
with the fuel at the
burner. |
| PRIMING |
The discharge of
steam containing
excessive quantities
of water in
suspension from a
boiler, due to
violent ebullition. |
| PROCESS
STEAM |
Steam used for
industrial purposes
other than for
producing power. |
| PRODUCTS
OF COMBUSTION |
The gases, vapors,
and solids resulting
form the combustion
of fuel. |
| PULSATION |
Rapid fluctuations
in pressure. |
| PURGE |
To introduce air
into the furnace and
the Boiler flue
passages in such
volume and manner as
to completely
replace the air or
gas-air mixture
contained therein. |
|
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Index |
|
Q
|
|
|
R
|
|
| RADIATION
LOSS |
A comprehensive
term used in a
boiler-unit heat
balance to account
for the conduction,
radiation, and
convection heat
losses from the
boiler to the
ambient air. |
| RATED
CAPACITY |
The manufacturers
stated capacity
rating for
mechanical
equipment; for
instance, the
maximum continuous
capacity in pounds
of steam per hour
for which a boiler
is designed. |
| RATE
OF BLOWDOWN |
A rate normally
expressed as a
percentage of the
Water fed. |
| RATING |
See LOAD |
| RAW
WATER |
Water supplied to
the plant before any
treatment. |
| REACTION |
A chemical
transformation or
change brought about
by the interaction
of two substances. |
| REASSOCIATION |
The recombination
of the products of
dissociation. |
| RECIRCULATION |
The reintroduction
of part of the
flowing fluid to
repeat the cycle of
circulation. |
| REDUCING
ATMOSPHERE |
An atmosphere
which tends to 1)
promote the removal
of oxygen from a
chemical compound;
2) promote the
reduction of
immersed materials. |
| REDUCTION |
Removal of oxygen
from a chemical
compound. |
| REFRACTORY |
Brickwork or
castable used in
boilers to protect
metal surfaces and
for Boiler baffles. |
| RELATIVE
HUMIDITY |
The ratio of the
mass of water vapor
present in a unit
volume of gas to the
maximum possible
mass of water vapor
in unit volume of
the same gas at the
same temperature and
pressure. |
| RELIEF
VALVE (Safety Relief
Valve) |
An automatic
pressure relieving
device actuated by
the pressure
upstream of the
valve and
characterized by
opening pop action
with further
increase in lift
with an increase in
pressure over
popping pressure. |
| RESIDUAL
FUELS |
Products remaining
from crude petroleum
by removal of some
of the water and an
appreciable
percentage of the
more volatile
hydrocarbons. |
| RESIN |
A bead-like
material used in
chemical exchange
for softeners and
dealkalizers. |
| RESISTANCE |
Impediment to gas
flow, such as
pressure drop or
draft loss through a
dust collector.
Usually measured in
inches water column
(iwc). |
| RETURN
FLOW OIL BURNER |
A mechanical
atomizing oil burner
in which part of the
oil supplied to the
atomizer is
withdrawn and
returned to storage
or to the oil line
supplying the
atomizer. |
| RINGELMANN
CHART |
A series of four
rectangular grids of
black lines of
varying widths
printed on a white
background, and used
as a criterion of
blackness for
determining smoke
density in stack gas
streams. |
| ROTARY
OIL BURNER |
A burner in which
atomization is
accomplished by
feeding oil to the
inside of a rapidly
rotating cup. |
|
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Index |
|
S
|
|
| SADDLE |
A casting,
fabricated chair, or
member used for the
purpose of support. |
| SAFE
WORKING PRESSURE |
See Design
Pressure |
| SAFETY
VALVE |
A spring loaded
valve that
automatically opens
when Pressure
attains the valve
setting. used to
prevent excessive
Pressure from
building up in a
boiler. |
| SAFETY
SHUT-OFF VALVE |
A manually opened,
electrically
latched,
electrically
operated safety
shut-off valve
designed to
automatically shut
off fuel when
de-energized. |
| SAMPLING |
The removal of a
portion of a
material for
examination or
analysis. |
| SATURATED
AIR |
Air which contains
the maximum amount
of Water vapor that
It can hold at its
temperature and
pressure. |
| SATURATED
STEAM |
Steam at the
temperature and
pressure at which
evaporation occurs. |
| SATURATED
TEMPERATURE |
The temperature at
which evaporation
occurs at a
particular pressure. |
| SATURATED
WATER |
Water at its
boiling point. |
| SCALE |
A hard coating or
layer of materials
on surfaces of
Boiler Pressure
parts. |
| SECONDARY
AIR |
Air for combustion
supplied to the
furnace to
supplement the
primary air. |
| SECONDARY
TREATMENT |
Treatment of
Boiler feed Water or
internal treatment
of Boiler-Water
after primary
treatment. |
| SEDIMENT |
(1)
Matter in water
which can be removed
from suspension by
gravity or
mechanical means.
(2) A
non-combustible
solid matter which
settles out at
bottom of a liquid;
a small percentage
is present in
residual fuel oils.
SEGREGatION - The
tendency of refus |
| SELF-SUPPORTING
STEEL STACK |
A steel stack of
sufficient strength
to require no
lateral support. |
| SERVICE
WATER |
General purpose
Water which may or
may not have been
treated for a
special purpose. |
| SHELL |
The cylindrical
portion of a
Pressure vessel. |
| SLUDGE |
A soft
Water-formed
sedimentary deposit
which normally can
be removed by
blowing down. |
| SLUG |
A large "dose" of
chemical treatment
applied internally
to a steam boiler
intermittently. Also
used sometimes
instead of "priming"
to denote a
discharge of water
out through a boiler
steam outlet in
relatively large
intermittent
amounts. |
| SMOKE |
Small gas borne
particles of carbon
or soot, less than 1
micron in size,
resulting from
incomplete
combustion of
carbonaceous
materials and of
sufficient number to
be observable. |
| SOFTENING |
The act of
reducing scale
forming calcium and
magnesium impurities
from water. |
| SOFT
WATER |
Water which
contains little or
no calcium or
magnesium salts, or
water from which
scale forming
impurities have been
removed or reduced. |
| SOLUTION |
A liquid, such as
Boiler Water,
containing dissolved
substances. |
| SOOT |
Unburned particles
of carbon derived
from hydrocarbons. |
| SOOT
BLOWER |
A mechanical
device for
discharging steam or
air to clean heat
absorbing surfaces. |
| SPALLING |
The breaking off
of the surface of
refractory material
as a result of
internal stresses. |
| SPECIFIC
HEAT |
The quantity of
heat, expressed in
Btu, required to
raise the
temperature of 1 lb
of a substance 1°F. |
| SPECIFIC
HUMIDITY |
The Weight of
Water vapor in a gas
Water-vapor mixture
per unit Weight of
dry gas. |
| SPRAY
ANGLE |
The angle included
between the sides of
the cone formed by
liquid fuel
discharged from
mechanical, rotary
atomizers and by
some forms of steam
or air atomizers. |
| SPRAY
NOZZLE |
A nozzle from
which a liquid fuel
is discharged in the
form of a spray. |
| STACK |
A vertical
conduit, which due
to the difference in
density between
internal and
external gases,
creates a draft at
its base. |
| STACK
DRAFT |
The magnitude of
the draft measured
at the inlet to the
stack. |
| STACK
EFFECT |
That portion of a
Pressure
differential
resulting from
difference in
elevation of the
points of
measurement. |
| STACK
EFFLUENT |
Gas and solid
products discharged
from stacks. |
| STAGNATION |
The condition of
being free from
movement or lacking
circulation. |
| STANDARD
AIR |
Dry air weighing
0.075 lb per cu ft
at sea level (29.92
in. Barometric
Pressure) and 70 °F. |
| STANDARD
FLUE GAS |
Gas weighing 0.078
lb per cu ft at sea
level (29.92 in.
Barometric Pressure)
and 70 °F. |
| STATIC
PRESSURE |
The measure of
potential energy of
a fluid. |
| STEAM |
The vapor phase of
Water, unmixed with
other gases. |
| STEAM
ATOMIZING OIL BURNER |
A burner for
firing Oil which is
atomized by steam.
It may be of the
inside or outside
mixing type. |
| STEAM
BINDING |
A restriction in
circulation due to a
steam pocket or a
rapid steam
formation. |
| STEAM
GAUGE |
A gauge for
indicating the
pressure of steam. |
| STEAM
GENERATING UNIT |
A unit to which
Water, fuel, and air
are supplied and in
which steam is
generated. It
consists of a Boiler
furnace, and fuel
burning equipment,
and may include as
component parts
Water walls,
superheater,
reheater,
economizer, air
heater, or any
combination thereof. |
| STEAM
PURITY |
The degree of
contamination.
Contamination is
expressed in ppm. |
| STEAM
QUALITY |
The percent by
Weight of vapor in a
steam and Water
mixture. |
| STEAM
SEPARATOR |
A device for
removing the
entrained Water from
steam. |
| STRAINER |
A device, such as
a filter, to retain
solid particles
allowing a liquid to
pass. |
| STRATIFICatION |
Non-homogeneity
existing
transversely in a
gas stream. |
| STUD |
A projecting pin
serving as a support
or means of
attachment. |
| SUPERHEATED
STEAM |
Steam with its
temperature raised
above that of
saturation. The
temperature in
excess of its
saturation
temperature is
referred to as
superheat. |
| SURFACE
BLOWOFF |
Removal of water,
foam, etc. from the
surface at the water
level in a boiler.
The equipment for
such removal. |
| SURGE |
The sudden
displacement or
movement of Water in
a closed vessel or
drum. |
| SUSPENDED
SOLIDS - |
Undissolved
solids in Boiler
water. |
| SWINGING
LOAD |
A load that
changes at
relatively short
intervals. |
|
Back to
Index |
|
T
|
|
| TERTIARY
AIR |
Air for combustion
supplied to the
furnace to
supplement the
primary and
secondary air. |
| THEORETICAL
AIR |
The quantity of
air required for
perfect combustion. |
| THEORETICAL
DRAFT |
The draft which
would be available
at the base of a
stack if there were
no friction or
acceleration losses
in the stack. |
| THEORETICAL
FLAME TEMPERATURE |
See Adiabatic
Flame Temperature |
| THERM |
A unit of heat
applied especially
to gas. One therm =
100,000 Btu. |
| THERMAL
EFFICIENCY |
The efficiency of
a Boiler, based on
the ratio of heat
absorbed to total
heat input. This
does not include
heat loss from the
boiler shell. |
| THERMAL
SHOCK |
A cycle of
temperature swings
that result in
failure of metal due
to expansion and
contraction. |
| THERMOCOUPLE |
A temperature
measuring
instrument. |
| TILE |
A preformed
refractory, usually
applied to shapes
other than standard
brick. |
| TOTAL
AIR |
The total quantity
of air supplied to
the fuel and
products of
combustion. percent
total air is the
ratio of total air
to theoretical air,
expressed as
percent. |
| TOTAL
PRESSURE |
The sum of the
static and velocity
pressures. |
| TOTAL
SOLIDS CONCENTRATION |
The Weight of
dissolved and
suspended impurities
in a unit Weight of
Boiler Water,
usually expressed in
ppm. |
| TRAP |
A receptacle for
the collection of
undesirable
material. |
| TREATED
WATER |
Water which has
been chemically
treated to make It
suitable for Boiler
feed. |
| TRIM |
Ancillary Boiler
components, like
Water level
controls, Pressure
controls, and
temperature
controls. |
| TUBE |
A hollow cylinder
for conveying
fluids. |
| TUBE
HOLE |
A hole in a drum,
heater, or tube
sheet to accommodate
a tube. |
| TURBULENT
BURNER |
A burner in which
fuel and air are
mixed and discharged
into the furnace in
such a manner as to
produce turbulent
flow from the
burner. |
| TURNDOWN
RATIO |
Ratio of maximum
to minimum fuel or
steam input or
Boiler output. |
|
Back to
Index |
|
U
|
|
| ULTIMATE
ANALYSIS |
See Analysis
Ultimate |
| UL
LISTED |
Product
certification that
indicates the
product meets safety
standards determined
by Underwriters
Laboratories. (ULC
and cUL indicate
Canadian
requirements.) |
| UNACCOUNTED-FOR
LOSS |
That portion of a
boiler heat balance
which represents the
difference between
100 per cent and the
sum of the heat
absorbed by the unit
and all the
classified losses
expressed as per
cent. |
| UNBURNED
COMBUSTIBLE |
The combustible
portion of the fuel
which is not
completely oxidized. |
| UNFIRED
PRESSURE VESSEL |
A vessel designed
to withstand
internal pressure,
neither subjected to
heat from products
of combustion nor an
integral part of a
fired pressure
vessel system. |
| USE
FACTOR |
The ratio of hours
in operation to the
total hours in that
period. |
|
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Index |
|
V
|
|
| VA |
Volt amperes. |
| VAPOR |
The Gaseous
product of
evaporation. |
| VAPORIZATION |
The change from
liquid or solid
phase to the vapor
phase. |
| VELOCITY
PRESSURE |
The measure of the
kinetic energy of a
fluid. |
| VENT |
An opening in a
vessel or other
enclosed space for
the removal of gas
or vapor. |
| VERTICAL
FIRING |
An arrangement of
a burner such that
air and fuel are
discharged into the
furnace in
practically a
vertical direction. |
| VISCOSITY |
Measure of the
internal friction of
a fluid or its
resistance to flow. |
| VOLATILE
MATTER |
Those products
given off by a
material as gas or
vapor, determined by
definite prescribed
methods. |
| VOLUME
OF AIR |
The number of cu
ft of air per min
expressed at fan
outlet conditions. |
|
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Index |
|
W
|
|
| WASTE
HEAT |
Sensible heat in
non-combustible
gases discharged to
the environment. |
| WATER |
A liquid composed
of two parts of
hydrogen and sixteen
parts oxygen by
weight. |
| WATER
COLUMN |
A vertical tubular
member connected at
its top and bottom
to the steam and
Water space
respectively of a
Boiler, to which the
Water gauge, Water
level controls, and
fuel cutoff may be
connected. |
| WATER
GAUGE |
The gauge glass
and its fittings for
attachment. |
| WATER
HAMMER |
A sudden increase
in Pressure of Water
due to an
instantaneous
conversion of
momentum to
pressure. |
| WATER
LEVEL |
The elevation of
the surface of the
Water in a boiler. |
| WATER
SOFTENER |
Removes hardness
(CaCO3) from water
through an ion
exchange of sodium
with calcium and
magnesium. |
| WATER
TUBE |
A tube in a boiler
having the water and
steam on the inside
and heat applied to
the outside. |
| WATER
VAPOR |
A synonym for
steam, usually used
to denote steam of
low absolute
pressure. |
| WEEP |
A term usually
applied to a minute
leak in a boiler
joint which forms
droplets (or tears)
of water very
slowly. |
| WETBACK
BOILER |
Firetube Boiler
design wherein the
back portion of the
Boiler has a Water
jacket. |
| WET-BULB
TEMPERATURE |
The Lowest
temperature which a
Water wetted body
will attain when
exposed to an air
current. This is the
temperature of
adiabatic
saturation, and can
be used to measure
humidity. |
| WETNESS |
A term used to
designate the
percentage of Water
in steam. Also used
to describe The
presence of a Water
film on heating
surface interiors. |
| WET
STEAM |
Steam containing
moisture. |
| WINDBOX |
A chamber below
the grate or
surrounding a
burner, through
which air under
pressure is supplied
for combustion of
the fuel. |
| WINDBOX
PRESSURE |
The static
Pressure in the
windbox of a burner
or stoker. |
|
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Index |
