| Term | Definition |
|---|
| 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.
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