vaporized at this point by radiant heat from above. The vapors rise and mix with the air drawn through the perforated holes in the burner. During high fire conditions, the flame burns above the top combustion ring, as shown in figure 4-8; and under low fire conditions, the flame burns in the lower portion or pilot ring of the burner, as shown in figure 4-9.

The PERFORATED SLEEVE BURNER consists of a metal base formed of two or more circular fuel vaporizing grooves and alternate air channels (fig. 4-10). Several pairs of perforated sleeves or cylinders force the air through the perforations into the oil vapor chamber. In this way a large number of jets of air are introduced into the oil vapor, bringing about a good mixture. This mixture burns with a blue flame and is clean and odorless.

These burners usually have a short kindling wick. Some burners have a cup below the base in which alcohol is burned to provide heat for starting. The wick and alcohol are used only for lighting.

Figure 4-8. - High fire flame.

Installation

Oil-burning heaters are portable and are easily moved from one location to another. For satisfactory operation, follow the installation procedures supplied by the manufacturer. In both pot type and perforated sleeve burners, oil is fed to the burner under control of a float-operated metering valve (fig. 4-11). Set the unit level so the oil can be properly distributed in the burner.

Figure 4-10. - Perforated sleeve burner.

Figure 4-9. - Low fire flame.

Figure 4-11. - Oil-controlled metering valve.