P99 LOW PRESSURE BOILERS:
CHAPTER 1 SIMPLIFIED EXAM
REVISION SUMMARY
Boiler
A closed metal container (pressure vessel) in which water
is heated to produce steam or heated water
Steam
Vapor that forms when water is heated to its boiling point
Heating Surface
The part of the boiler where water is on one side and heat
from the gases of combustion on the other.
Internal Furnace
A furnace in a boiler that is surrounded by heating surface.
Thermal Efficiency
Ratio of heat absorbed by the water to the heat provided
by the fuel.
Condensate
Steam that has lost its heat and returned to water.
Makeup Water
Fresh water added to a boiler to make up for the water
loss due to leaks or lost condensate.
Feedwater
Water that is treated for use in a boiler.
Backflow Preventer
Device consisting of two check valves and an overflow
device built into the same body, used to prevent water
from backing up into a water supply system.
, Thermodynamics
The science of thermal energy (heat) and how it
transforms to and from other forms of energy.
First Law of Thermodynamics
The law of conservation of energy states that energy
cannot be created or destroyed but can change state from
one form to another.
Second Law of Thermodynamics
Heat always flows from a material having a higher
temperature to a material having a lower temperature.
Gases of Combustion
Gases produced by the combustion process in a boiler
and discharged to the atmosphere.
Heat
Form of energy identified by a temperature difference or a
change of state.
Solid
Substance without an internal cavity that has a definite
size and shape.
Liquid
Substance that flows freely and has a definite volume but
no independent shape.
Gas
Substance that has no definite volume or independent
shape that tends to expand indefinitely.
Change of State
Process that occurs when enough heat is added or
removed to change a substance from one physical state to
another.
Sensible Heat
CHAPTER 1 SIMPLIFIED EXAM
REVISION SUMMARY
Boiler
A closed metal container (pressure vessel) in which water
is heated to produce steam or heated water
Steam
Vapor that forms when water is heated to its boiling point
Heating Surface
The part of the boiler where water is on one side and heat
from the gases of combustion on the other.
Internal Furnace
A furnace in a boiler that is surrounded by heating surface.
Thermal Efficiency
Ratio of heat absorbed by the water to the heat provided
by the fuel.
Condensate
Steam that has lost its heat and returned to water.
Makeup Water
Fresh water added to a boiler to make up for the water
loss due to leaks or lost condensate.
Feedwater
Water that is treated for use in a boiler.
Backflow Preventer
Device consisting of two check valves and an overflow
device built into the same body, used to prevent water
from backing up into a water supply system.
, Thermodynamics
The science of thermal energy (heat) and how it
transforms to and from other forms of energy.
First Law of Thermodynamics
The law of conservation of energy states that energy
cannot be created or destroyed but can change state from
one form to another.
Second Law of Thermodynamics
Heat always flows from a material having a higher
temperature to a material having a lower temperature.
Gases of Combustion
Gases produced by the combustion process in a boiler
and discharged to the atmosphere.
Heat
Form of energy identified by a temperature difference or a
change of state.
Solid
Substance without an internal cavity that has a definite
size and shape.
Liquid
Substance that flows freely and has a definite volume but
no independent shape.
Gas
Substance that has no definite volume or independent
shape that tends to expand indefinitely.
Change of State
Process that occurs when enough heat is added or
removed to change a substance from one physical state to
another.
Sensible Heat
