Garland 40 Series Technical Reference Manual - page 68
Part # GCTRM Rev 3 (12/10/09)
Page 68
LimitsofFlammability: Upper and lower ranges of gas in
the air-gas mixture that will support combustion. Low
amount of fuel makes mixture lean. High amount of fuel
renders mixture rich.
Manifold: The conduit of an appliance, which supplies gas to
the individual burners.
ManifoldPressure: The gas pressure in an appliance
manifold, upstream of burner orifices.
ManufacturedGas: A fuel gas that is artificially produced by
some process, as opposed to natural gas, which is found
in the earth. Sometimes called “town gas”.
Methane:A hydrocarbon gas with formula CH4, one carbon
atom linked to four hydrogen atoms. The principal
component of natural gas.
MixedGas: A gas in which the heating value of
manufactured gas is raised by co-mingling with natural
or LPG (except where natural gas or LPG is used only for
“enriching” or “reforming”)
Mixer: That portion of a burner where air and gas are mixed
before delivery to the burner ports.
1. Mixer Face: The air inlet end of the mixer head.
2. Mixer Head: That portion of an injection type burner,
usually enlarged, into which primary air flows to mix
with the gas stream
3. Mixer Throat: (Venturi) That portion of the mixer
which has the smallest cross-sectional area, and
which lies between the mixer head and the mixer
tube.
4. Mixer Tube: That portion of the mixer, which lies
between the throat and the burner head.
NaturalDraft: The motion of flue products through an
appliance generated by hot flue gases rising in a vent
connected to the furnace outlet.
NaturalGas:A fuel which is derived from the earth
consisting primarily of Methane (CH4). Natural gas is
considered non-toxic and non-poisonous. Natural gas has
little or no odor in its refined state. Odorants are added,
such as mercaptan and sulphur compounds, to aid in leak
detection.
Orifice:An opening in an orifice cap (hood), orifice spud or
other device through which gas is discharged, whereby
the flow of gas is limited and/or controlled. (See also
universal orifice)
Overrating: Overrating is the operation of a gas burner at a
greater rate than it was designed for.
Port: Any opening in a burner head through which gas or an
air-gas mixture is discharged for ignition.
PortLoading:The input rate of a gas burner per unit of port
area, obtained by dividing input rate by total port area.
Usually expressed in terms of BTU per hour per square in
of port area.
PressureRegulator: A device for controlling and maintaining
a uniform outlet gas pressure.
PrimaryAir: The combustion air introduced into a burner,
which mixes with the gas before it reaches the burner
port. Usually expressed as a percentage of air required
for complete combustion of the gas. Ideal burning
conditions generally is 10 cubic feet of air per cubic foot
of gas.
PrimaryAirInlet: The opening or openings through which
primary air is admitted into a burner. Products of
Combustion: Carbon dioxide and water vapor formed in
burning plus the nitrogen in the reactants that entered
with the combustion air.
Propane: A hydrocarbon gas heavier than methane but
lighter than butane. It is used as a fuel gas alone, mixed
with air or as a major constituent of liquefied petroleum
gases.
RichMixture: A mixture of gas and air containing too much
fuel or too little air for complete combustion of the gas.
SecondaryAir: Combustion air externally supplied to
a burner flame at the point of combustion. It is the
remaining air required for complete combustion besides
primary air.
SoftFlame:A flame partially deprived of primary air such
that the combustion zone is extended and inner cone is
ill-defined.
Soot: A black substance, mostly consisting of small particles
of carbon, which can result from incomplete combustion
and appear as smoke.
SpecificGravity: The weight of one cubic foot of gas
compared to one cubic foot of dry air, at a common
pressure and temperature. The specific gravity of a gas
determines whether it will rise or fall when released
into air. Air is given a specific gravity rating of 1.0. Since
natural gases have a specific gravity of 0.4 to 0.8, it will
rise when released into the air. Propane gas, however,
with a specific gravity rating of 1.5 and butane gas 2.0
both will fall when released into air.
UniversalOrifice: A combination fixed and adjustable orifice
designed for the use of two different gases, such as LPG
and natural gas.