Garland 40 Series Technical Reference Manual - page 67
Part # GCTRM Rev 3 (12/10/09)
Page 67
FlameVelocity: The speed at which a flame travels through a
fuel-air-mixture. Burning speeds vary with types of gases,
and the amount of air mixed with the gas. This air to gas
ratio is very important in that it is directly related to flame
stability
Flashback: An undesirable flame characteristic in which
burner flames strike back into a burner to burn there or
to create a pop after the gas supply has been turned off.
Flashback occurs when
gas-air flow velocity is less than burning speed at some
point near a burner port. Flashback is a condition
where gas ignites within the burner. Any factor, which
increases burning speed, tends to promote flashback,
and any factor decreasing flow velocity from the ports
will contribute to flashback. Flashback is more prevalent
with faster burning gases. Natural gas is a relatively slow
burning gas hence flashback is less likely. Reducing
primary air is the usual cure for flashback.
FlashbackArrestor: A gauze, grid or any other portion of a
burner assembly used to avert flashback.
Flashtube: An ignition device, commonly used for igniting
gas on range top burners. An air-gas mixture from the
burner body is injected into the end of a short tube. The
mixture moves along the tube, is ignited by a standing
pilot flame at the other open end of the tube and the
flame travels back through the mixture in the flashtube to
ignite the gas at the burner ports.
FloatingFlames: An undesirable burner operating condition,
usually indicating incomplete combustion in which
flames leave the burner ports to “reach” for combustion
air.
FlueGases,FlueProducts: The combination of combustion
products and excess air leaving the combustion area.
Since water is produced as a vapor in the burning of
the gas, it is also present in the flue products. If the flue
products and vent system remain hot enough, this
vapor is harmlessly discharged. If not, the vapor can
reach the dew point and condense into water, which can
accumulate in the system.
FlueLoss: The heat lost in flue products exiting from the flue
outlet of an appliance.
FlueOutlet:The opening provided in am appliance for the
escape of flue gases.
IgnitionTemperature:Temperature at which an air-gas
mixture will initiate and support combustion
InchesofMercuryColumn: A unit used in measuring
pressures. One inch of mercury column equals a pressure
of 0.491 pounds per square inch.
InchesofWaterColumn: A unit used in measuring pressures.
One inch of water column equals a pressure of 0.578
ounces per square inch. One inch mercury column equals
about 13.6 inches water column.
IncompleteCombustion: Combustion in which the fuel is
only partially burned. A poorly vented appliance restricts
flow of air into an appliance. Lack of ventilation around an
appliance may lower oxygen content in the surrounding
air. This can be a result of spillage of combustion products
into the room as well. These conditions can cause
incomplete combustion and poor performance of an
appliance. Adequate, but not excessive ventilation is a
must and cannot be over emphasized.
Inerts:Non-combustible substances in a fuel, or in flue
gasses, such as nitrogen or carbon dioxide.
InfraredBurner(RadiantBurner): A burner, which is
designed to operate with a hot, glowing surface. A
substantial amount of its energy output is in the form of
infrared radiant energy.
Injection: Drawing primary air into a gas burner by means of
a flow of fuel gas.
InputRate: The quantity of heat or fuel supplied to an
appliance, expressed in volume or heat units per unit
time, such as cubic feet per hour or BTU per hour.
InputRating:The gas burning capacity of an appliance in
BTU per hour as specified by the manufacturer. Appliance
input ratings are based on sea level operation and need
not be changed for operation up to 2 000 feet elevation.
For operation at elevations above 2 000 feet, input ratings
should be reduced at the rate of 4 percent for each 1 000
feet above sea level.
LeanMixture: An air-gas mixture, which contains more air
that the amount needed for complete combustion of the
gas.
LiftingFlames:An unstable burner flame condition in
which flames lift or blow off the burner port(s). Excessive
primary air can cause flames to lift and blow off the
burner ports, which can be noisy as well as inefficient.
More importantly, however, is the production of
dangerous carbon monoxide under this condition. Any
factor, which reduces burning speed, promotes lifting
flames. Also, any factor, which increases flow velocity
from ports, contributes to lifting flames. Over-firing of
burners is also a cause. The normal cure for lifting flames
is the reduction of primary air input to the burner.
LiquefiedPetroleumGases: The terms “Liquefied Petroleum
Gases”, “LPG” and “LP Gas” mean and include any fuel gas
which is composed predominantly of any of the following
hydrocarbons, or mixtures of them: propane, propylene,
normal butane or isobutane and butylenes.