Low Pressure Boilers Ch. 6
Approximately 75 lb of air is required for every pound of fuel burned.
False
Draft gauges are calibrated in the same way as pressure gauges.
False
Gases move from an area of low pressure to an area of high pressure.
False
___ draft is produced when air is pushed through the burner.
Forced
Mechanical draft is produced by a fan or blower.
True
Natural draft produces greater amounts of draft in the winter than in the summer.
True
Proper control of draft results in higher combustion efficiency.
True
Some boilers have combination forced and induced draft fans.
True
The amount of draft determines the rate of combustion.
True
The amount of natural draft generated is affected by the height of the chimney.
True
When using a manometer to measure draft, the liquid level in one leg is compared to the liquid level in the other leg.
True
When using natural draft, the boiler is limited in the amount of fuel that can be burned.
True
Dampers are used to control the flow of air and gases of combustion.
True
Draft is the difference in pressure between two areas that causes air or gases of combustion to flow.
True
Extraordinary changes that occur in the oxygen content of the gases of combustion indicate a potential problem in the fuel system and/or draft system.
True
Draft gauge measurements are expressed in inches of ___.
water column
Cold outside air affects the amount of ___ draft produced.
natural
When using ___ draft, the boiler is limited in the amount of fuel that can be burned.
natural
Mechanical draft is produced by ___.
power-driven fans
The forced draft fan is located in the breeching.
False
The induced draft fan is located on the front of the boiler.
False
The two types of draft are mechanical and forced.
False
___ draft is air that is pulled through the boiler.
Induced
A cool stack condition can result in condensation of water vapor in the gases of combustion.
True
Air is necessary for combustion process to take place.
True
The two types of mechanical draft are forced and induced.
True
Draft is the difference in pressure between two points that causes ___ to flow.
air, natural gas, gases of combustion
When measuring draft in the boiler, one leg of the tube is open to the boiler and the other to the ___.
atmosphere
Combination forced and induced draft is also known as ___ draft.
balanced
The induced draft fan is located in the ___.
breeching
The amount of natural draft present can be affected by ___.
dampers opened or closed, temperature of the gases of combustion, height of the chimney
High combustion efficiency produces the maximum amount of ___ generated by the fuel.
heat
A ___ is a simple draft gauge consisting of a U-shaped glass tube.
manometer
By using ___ draft, higher rates of combustion can be achieved.
mechanical
Forced draft and induced draft are two types of ___ draft.
mechanical
Improperly burned fuel results in ___.
soot and smoke
A ___ is a steel chimney used to direct the flow of gases of combustion from the boiler to the atmosphere.
stack
Too much draft when burning coal may cause ___.
too hot a fire
