Document MJBXgD6JOL0k26GBEEY1e3pk7

804 CHAPTER 50 ' 1.965'Guide And Data:Book : BIBLIOGRAPHY R. Schubert: Determination of fluidity of refrigeration oils at low temperatures (KiUeteehnik, VoL 9, No. 2, 1957, p. 40). F. P. Bowden and D. Tabor: Friction and Lubrication (John Wiley and 8oos, Inc., New York/1956). EL S. Ross: Selection and use of oils for refrigeration units (Air Conditioning, Heating and Ventilating, VoL 55, No. 10, pp. 97-106). - . H. Heckmatt: Some lubrication problems of refrigerating ma chines using F12 (Journal of Refrigeration, VoL 3, No. 1, 1960, p.5). - ' ,1'. . T.'P. Hughes, Jr.: Application of refrigerator lubrication system to heat pumps (Journal of Refrigeration, VoL 3, No. 1, H. Steinle: The surface tension of refrigerants, of; lubricants, and of their mixtures (KSltetecJmik, VoL 12, No. 11, 1960, p. 334). O. C. Rutledge: Viscosity of oils diluted with refrigerants (Rbfbigebaitnq Enoinzeeinq, January 1938, p. 31). K. Q. Mackenzie: Tests for lubricating oils (Rctbigebatino Enginessing, April 1951, p. 375). L. A. Philipp and B. E. Tiffany: Thermodynamics of sulfur dioxide-oil systems (Retkigeuatino Engineering, May 1934, p. 248). 1960, p! 12). EL J. LOffler: Review of refrigerants and mixtures of oils and refrigerants (KSltetechnik, VoL 9, No. 11, 1957, p. 358). Freoo Products Division, E. I. duPont deNemours and Co., Inc. (Bulletina RT-20, September 1955; D-34, undated; and D-35, undated). H. J. LOffler: Fluidity of oil-Frigeh 22 mixtures at low tempera IL The Texas Company. Lubricants for Refrigeration Systems tures (K&lUtecknik, VoL 11, No. 9, 1959, p. 258). (1957 revision). Orvfc* : ?r: . CHAPTER 51 AUTOMATIC FUEL-BURNING EQUIPMENT Classification of Stokers, Combustion Process and Adjustments, Combustion Chamber Design, Classification of Oil Burners, Types of Burners; Combustion Process, Storing and Handling Heavy Fuel Oil; Oit Storage Tanks and Piping; Classification of Gas-Fired Heating Equipment, Combustion Process and Adjustment Ratings; Sizing of Gas Piping, Fuel-Burning Rates; Controls for Automatic Fuei-Buming Equipment AUTOMATIC mechanical equipment for the combustion of solid, liquid, and gaseous -fuels is considered in this chapter. The type of fuel to be burned affects the design of the heat exchanger (furnace, boiler, etc.); therefore, one should refer to Chapter 52, Heating Boilers, Furnaces, Space Heaters, when considering fuels arid1fuel-burning equipment. Some heat exchangers are designed specifically for one type of fuel. As a result, maximrim efficiency and best perform ance require the simultaneous consideration of fuel and fuelburning equipment'during the-initial stages of equipment selection.- MECHANICAL STOKERS A mechanical stoker is'a device that feeds a solid fuel into a combustion chamber, provides a supply of air for burning the fuel under automatic control and, in some' cases, incor porates a' means of removing'the ash and refuse of combus tion automatically. Coal can be burned more efficiently by a mechanical stoker than by hand firing because the stoker provides a uniform' rate of fuel feed, better distribution in the fuel bed, and positive 'control of the air supplied for com bustion. In many cities, measures for control of excess smoke re quire installation' of stokers even in residences, unless fuel used contains less volatile matter than bituminous coaL Classification of Stokers According to Capacity Stokers, may be classified roughly according to th*ir coal burning capacities, as follows: Class X 10 to 100 Ib per hr Class 2 100 to 300 lb per hr Class 3 '300 to 1200 lb per hr Class 4 over 1200 lb per hr . ..................... Gass 1 Stokers : These stokers are used primarily for-home heating and are designed for quiet, automatic operation. Tb* eenen] rrspoosilality (or this chapter b *--;--1 to TC Sa. Combmtipn aad Foele. They are usually of the underfeed type with a screw feed. Stokers in this class are made, for burning anthracite, bitu minous, semi-bituminous, and lignite coals, and coke. They are designed to feed coal to the furnace intermittently in accordance with temperature, or pressure demand. A special control is used to mumt-ain & fire during periods when no heat is required. Stokers in this class may have automatic or manual ash removal. The U. S. Department of Commerce has issued commercial standards for household anthracite stokers.1 Gass 2 Stokers Stokers of this class are usually of the underfeed type and are used extensively for heating apartments, schools, hotels, and commercial installations. They ore available for burning anthracite, bituminous, and lignite coals. Ash removal may be automatic or manuaL Gass 3 and 4 Stokers These stokers may be of the underfeed type, overfeed fiat grate type, overfeed inclined grate type, or the vibrating grate type. The grate type stokers may be of the traveling grate type or they may be of the stationary grate type with overhead feed. The latter is sometimes referredto as a spreader type stoker.' Information on stoker-fired equipment is available from the National Coal Association.1 Combustion Process In anthracite stokers of the underfeed type, burning takes place entirely within the stoker retort. ' Stokers designed for handling bituminous coals are de signed to ignite and bum the volatile matter released from the coal as it is heated. This is provided for with underfeed stokers and with the chain grate type of.stoker by locating and con trolling the feed of fresh coal into the combustion zone. - With the underfeed stoker the volatile gases must pass through the hottest part of the burning bed of fuel and are thus ignited. In the traveling grate type stoker or the vibrating grate type stoker, the fuel is fed in at the front end. As the volatile 805