Document O1KLerJ4Oo6aJEwQVE0Nw0nJw

200|_____________________________________________________ Chapter 10 ___________ 1__1945 Guide "obtained by'meahs "df_arKigtPvortage_electric spark used" alone, or isprimary ignition for a gas pilot. The high-pressure atomizing type, illustrated in Fig. 12, is characterized by an air tube, usually horizontal, with oil supply pipe centrally located in the tube and arranged so that a spray of atomized oil is introduced, at about 100 lb per square inch, and mixed in the combustion chamber with the air stream emerging from the air tube. A variety of patented. shapes is employed at the end of the air tube to influence the direction and speed of the air and thus the effectiveness of the mixing process. . This type of burner utilizes a fan to supply the air for combustion, and ignition is established by a high-voltage electric spark that may be operative continuously while the burner is running, or just at the beginning of the running period. Gun type burners operate on the intermittent on-off principle, and with a luminous flame. The combustion process is completed in a chamber constructed of Fig. 12. High-Pressure Atomizing Oil.Burner refractory material, or stainless steel, this being a part of the installation. Pressure-atomizing burners generally use the distillate oils, No. 1, 2 or 3 grade. (See Chapter 8). Rotary Type This class of burners may be divided into two groups: vertical, and horizontal. Most of the smaller rotary burners are of the vertical type, and use the lighter distillate oils, No. 1 or 2 grade. The most distinguishing feature of vertical rotary burners is the principle of flame application. These burners are of two general types: the center flame and wall flame. In the former type (Fig. 13), the oil is atomized by being thrown from the rim of a revolving disc or cup and the flame burns in suspension with a characteristic yellow color. Combustion is supported by means of a bowl-shaped chamber or hearth. The wall flame burner (Fig. 14) differs in that combustion takes place in a ring of stainless steel or refractory material, which is placed around the hearth. Dependent upon combustion adjustment, these burners may operate with either a semi-luminous or non-luminous flame. Both types of vertical rotary burners are further characterized by their installation within the ash pit of the boiler or furnace. Various types of Automatic Fuel Burning Equipment 201 Fig. 13. Center Flame Vertical Rotary Burner Fig. 14. Wall Flame Vertical Rotary Burner ignition are utilized, gas and electric, either spark or hot wire. The air for combustion is supplied partially by natural draft, and partially by fan effect of the central spinner element. Horizontal rotary burners are used principally to burn the heavier oils, Nos. 5 and 6 grades, principally in larger commercial and industrial installations, although domestic sizes are available. Such burners are of the mechanical atomizing type, using rotating cups which throw the oil from the edge of the cup at high velocity into the surrounding stream of air delivered by the blower (Fig. 15). Horizontal rotary burners commonly use a combination electric-gas ignition system, or are lighted manually. Primary air for combustion is supplied by a blower, and secondary air, often introduced through a checkerwork in the combustion chamber, is controlled by chimney draft. These burners operate with a luminous flame, usually on high-low or continuous setting. ' In larger installations, burners may be installed in multiple in a common combustion chamber. Because of the high viscosity oils used in these