P99 HIGH AND LOW PRESSURE
BOILERS EXAM REVISION SUMMARY
condensate
steam that has lost its heat and returned to water
feed water
water that is treated for use in the boiler
back flow preventer
(check valve) prevents flow of the boiler water back to the
city water line
thermo dynamics
how heat is transferred (high to low) and created
sensible heat
heat that can be measured with a thermometer or sensed
latent heat
change in state and no temperature change of substance
heat transfer
movement of heat from one material to another
(conduction, convection, radiation)
heat exchange
anything that transfers heat from one substance to another
without allowing the materials to mix
combustion
the rapid union of oxygen with an element or compound
that results in the release of heat (perfect, complete,
incomplete)
primary air
air that controls the combustion rate
secondary air
, dressed the flame
excess air
air above the theoretical amount required to burn the fuel
how many pounds of air are required to burn a pound
of fuel
14 to 15lbs
MAWP
maximum allowable working pressure
Boiler Horse Power
evaporation of 34.5 lbs/hr of water @ 212 degrees (33,472
BTU/hr)
fire tube boiler
heat and gases of combustion pass through tubes
surrounded by water (scotch marine boiler)
water tube boiler
water passes through tubes surrounded by gases of
combustion
ASME
American Society of Mechanical Engineers
High Pressure Boiler
has a MAWP above 15 psi and over 6 boiler hp
Low Pressure boiler
has a MAWP below 15 psi
Atmospheric pressure
pressure caused by the weight of air surrounding the earth
(14.7 psi at sea level, every 1000 ft we lose 1/2 lb)
Absolute pressure
the sum of guage pressure and atmospheric pressure
(add 14.7)
package boiler
preassembled at the factory
BOILERS EXAM REVISION SUMMARY
condensate
steam that has lost its heat and returned to water
feed water
water that is treated for use in the boiler
back flow preventer
(check valve) prevents flow of the boiler water back to the
city water line
thermo dynamics
how heat is transferred (high to low) and created
sensible heat
heat that can be measured with a thermometer or sensed
latent heat
change in state and no temperature change of substance
heat transfer
movement of heat from one material to another
(conduction, convection, radiation)
heat exchange
anything that transfers heat from one substance to another
without allowing the materials to mix
combustion
the rapid union of oxygen with an element or compound
that results in the release of heat (perfect, complete,
incomplete)
primary air
air that controls the combustion rate
secondary air
, dressed the flame
excess air
air above the theoretical amount required to burn the fuel
how many pounds of air are required to burn a pound
of fuel
14 to 15lbs
MAWP
maximum allowable working pressure
Boiler Horse Power
evaporation of 34.5 lbs/hr of water @ 212 degrees (33,472
BTU/hr)
fire tube boiler
heat and gases of combustion pass through tubes
surrounded by water (scotch marine boiler)
water tube boiler
water passes through tubes surrounded by gases of
combustion
ASME
American Society of Mechanical Engineers
High Pressure Boiler
has a MAWP above 15 psi and over 6 boiler hp
Low Pressure boiler
has a MAWP below 15 psi
Atmospheric pressure
pressure caused by the weight of air surrounding the earth
(14.7 psi at sea level, every 1000 ft we lose 1/2 lb)
Absolute pressure
the sum of guage pressure and atmospheric pressure
(add 14.7)
package boiler
preassembled at the factory
