Firetube Boilers
Passageways that allow a person to enter a steam drum for cleaning and inspection.
What are access doors (aka mandoors)?
This component provides a receptacle for the accumulation of scale and other solid matter in the boiler while distributing water to the generator tubes.
What is the mud drum?
or What is the water drum?
A measure of the potential for heat transfer but not an indicator of how much heat is or will be transferred.
What is temperature?
A device that measures a process condition. For example, a level indicator that measures boiler drum level.
What is a primary element?
Superheaters that increase steam temperature as the firing rate increases.
What are convection superheaters?
A small hole drilled into the stay bolt of a firetube boiler. When a stay bolt cracks, this hole will leak water informing the operator of a problem.
What is a tell-tale hole?
A component that accumulates steam generated in tubes and provides a space for separation of moisture from steam prior to leaving the boiler.
What is a steam drum?
The amount of heat required to change water to steam. It is 970.4 btu/lb water at atmospheric pressure.
What is the latent heat of vaporization?
These are located after every pressure reducing station on the steam line to protect down stream components.
What are safety relief valves?
Superheaters that decrease steam temperature as the firing rate increases.
What are radiant superheaters?
A pipe that runs the length of the firetube boiler so that water is added evenly throughout.
What is a feed pipe?
A method of controlling superheater outlet temperature by combining either pure water or saturated steam with the superheated steam to maintain a constant temperature.
What is attemperation?
Heat transfer that is measured as a change in temperature.
What is sensible heat?
The condition being controlled by the control system. An example of this is steam flow rate.
What is a process variable?
A fan located in the exhaust breaching of a boiler used to pull air through the furnace.
What is an induced draft fan?
This component is installed in the crown sheet of a firetube boiler and is used to warn operators of low boiler water level. It can even help to extinguish the furnace.
What is a fusible plug?
The upper half of the steam drum.
What is the wrapper sheet?
Heat energy traveling with the fluid material, warmer water rises and cooler water falls due to density.
What is convection?
Produced by a fan that supplies air to the furnace inlet.
What is forced draft?
This valve is located on the feedwater line, closest to the boiler drum. It is installed so that the check valve can be repaired without draining the boiler.
What is a stop valve?
A component located at the top of the pressure vessel. It has slots so that the wet steam has to change direction, this allows moisture to fall out of the steam.
What is a dry pipe?
A term used to describe superheated steam that has been attemperated and thus is no longer in a superheated state.
What is desuperheated steam?
The unit used for measuring heat quantity.
Equal to the amount of heat required to raise the temperature of one pound of water at its maximum density (occurs at a temperature of 39.1 degrees °F) by 1°F.
What is a BTU (British Thermal Unit).
A device that controls the flow of material or energy to keep the process condition at the desire setpoint. For example, a feedwater regulator valve controls the flow of feedwater to the drum and maintains it at the desired level - NOWL.
What is a final element?
The sheet or plate attached to pressure parts for supporting, insulating, or forming a gas-tight enclosure.
What is the boiler casing?