Furnaces
The stack damper in a furnace is set to give from?
0.05 to 0.15 inches of water
Section of the furnace that contains the burners and open flames is called ____.
Firebox
When a burner flame goes out during operation it is referred to as:
Flame out
_____furnaces use a fan to push fresh air to the burners for combustion.
Forced Draft Furnaces
_____ is located on the natural gas fuel line to the furnace that is designed to maintain constant pressure to the surface burner.
Fuel pressure control loop
A device used to heat up chemicals or chemical mixtures is _____.
Furnace
_____ are designed to be operated with lower amounts of excess air than typical burners.
Low NOx Burners
Fire Triangle
fuel, oxygen, heat
When a furnace tube or section of refractory gets too hot.
hot spot
Decreasing excess air in the furnace ____ radiant heat transfer
maximizes
Most fired furnaces use
natural gas.
Temperatures in furnaces range between
1600F to 2000F
Hydrogen as fuel has a fuel heat value of:
274 BTU/Cu.ft
Convective heat transfer accounts for ____.
30 to 40%
Gas flow out of a furnace is typically set at:
350,000 pounds per hour
Radiant heat transfer accounts for?
60% to 70%
_____ heats air before it enters a furnace at the burners.
Air preheater
_____ furnace requires 2 fans one inducing flow out the stack and one providing positive pressure to the burners.
Balanced Draft Furnaces
Four draft types utilized on furnace designs are:
Balanced, Induced, Forced, and Natural
_____ are located on each burner and will immediately alert a technician when a burner goes out or is functioning outside normal parameters.
Burner Alarms
CH4+2O2 combustion yields what?
CO2+2H2O
____ is formation of carbon deposits in the tubes of a furnace.
Coking
_____ shows 10 tube color variations associated with temperature.
Color chart of steel tubes
____ are located on the roof of the furnace and are not in direct contact with the burner flames.
Convection Tubes
Tubes located above the shock bank is called ___.
Convection tubes
Negative pressure of air and gas at different elevations in a furnace is called _____.
Draft
_____ airflow will decrease furnace temperatures around the burners and force the automatic controls to increase natural gas flow rates to the burner, wasting money.
Excess air
____ furnace has a fan located below the stack pulls air up through the firebox and out the stack.
Induced-draft furnace
____ furnaces are not equipped with fans. Hot combustion gases flow through the furnace using natural bouncy forces.
Natural Draft Furnaces
____ allows for visual inspection using a welders shield.
Peepholes
Amount of combustibles in the flue gas?
Percent combustibles
Tubes located along the walls of the firebox are called _____.
Radiant Tubes