Document X8wDY3DYVja2GQ2XezdQMkKK

Heating Ventilating Air Conditioning Guide 1939 refractory material, which is placed around the hearth. These types of burners are further characterized by their installation within the ashpit of the boiler or furnace. The pot type burner (Fig. 13) can be identified by the presence of a metal structure, called a pot or retort, in which combustion takes place When gun type (pressure atomizing) or horizontal rotary burners are Chapter 11- Automatic Fuel Burning Equipment a that while the heavier grades of oil have a smaller heat value per found t havei due to greater density, a larger heat value per gallon. ^i.Un lative economy of the various grades must be based upon price and The amount of excess air required for clean and efficient combustion. Boiler-Burner Units Boilers and air conditioners especially designed for oil burners are liable to the purchaser of this type of equipment. They are used for 3 nlacements as well as for new installations. This type of equipment rePi~jlv j,as more heating surface than the older coal-burning designs. Flue proportions and gas travel have been changed with beneficial results. smm- Fig. 10. Gun Type Pressure Atomizing Oil Burner Fig. 11. Center Flame Vertical Rotary Burner Fig. '12. Wall Flame Vertical Rotary Burner used the combustion chamber is usually constructed of firebrick or other suitable refractory material, and is part of the installation procedure. The oil burners are operated by a small electric motor which pumps the oil and some or all of the air required. The smallest sizes can generally burn not much less than 1 gal of oil per hour. The grade of oil burned ranges from No. 1 to No. 3. No. 3 oil is the heaviest and most viscous of the various grades mentioned. An oil burner satisfactory for No. 3 oil can burn any of the lighter grades easily but an oil burner recommended for No. 2 oil should never be supplied with the heavier grades. It has been 220 All problems of combustion chamber design, capacities, efficiencies, etc., have been solved. The selection of the proper size of unit should be a simple process. COMMERCIAL OIL BURNERS Liquid fuels are used for heating apartment buildings, hotels, public and office buildings, schools, churches, hospitals, department stores, as well as industrial plants of all kinds. Contrary to domestic heating, con venience seldom is a dominating factor, the actual net cost of -heat pro duction usually controlling the selection of fuel. Some of the largest office buildings have been using oil for many years. Many department stores have found that floor space in basements and sub-basements can be used to better advantage for merchandising wares, and credit the heat pro ducing department with this saving. Wherever possible, the boiler plant should be so arranged that either oil. or solid fuel can be used at will, permitting the management to take advantage of changes in fuel costs if any occur. Each case should be considered solely in the light of local conditions and' prices, r Burners for commercial heating may be either large models of types used in domestic heating, or special types developed to meet the condi tions imposed by the boilers involved. Generally speaking, such burners are of the mechanical or pressure atomizing types, the former using rotating cups, producing a horizontal torch-like flame. (Fig. 14). As much as 350 gal of oil per hour can be burned in these units, and frequently, they 221