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Fuel o xygen heat, Characteristics of gas fuels, The combustion properties – Whirlpool 4322452 User Manual

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Page 1-4

CHARACTERISTICS OF GAS FUELS

Each of the four types of gas has a specific boiling point (see Figure 1-2). The

boiling point

is

referred to as the temperature where gas turns from a liquid to a gas at atmospheric pressure. If
temperatures fall below the freezing point (32˚F), the liquid will not turn into a gas, and there will
be no flame.

By itself, gas cannot be ignited. Fuel, oxygen, and heat are necessary for combustion to occur.
Remove one of these, and combustion cannot take place (see Figure 1-3).

200

100

32

– 44

–100

– 200

– 300

Zero

Butane

Propane

L.P.

Natural
Mixed
Manufactured

Fahrenheit

Degrees

BOILING POINT OF GAS

FUEL

O

XYGEN

HEAT

THE COMBUSTION PROPERTIES

Figure 1-2

Figure 1-3

Gases will ignite at temperatures between 900˚F and 1200˚F.

A proper mixture, or ratio, of gas and air is needed to produce a flame. If the air-to-gas ratio is not
correct, incomplete combustion, or an improper flame, will result. The ratio needed to ignite natural
gas (10:1) is shown in Figure 1-4, and the ratio for L.P. gas (24:1) is shown in Figure 1-5.

Figure 1-4

Figure 1-5

1 cu.ft.

Gas

1000 BTU Heat

Natural Gas (10:1)

10 cu. ft. Air To 1 cu.ft. Gas

10 cu.ft.

Air

1 cu.ft.

Gas

1000 BTU Heat

L.P. Gas (24:1)

24 cu. ft. Air To 1 cu.ft. Gas

24 cu.ft.

Air