(15) (16) Draft between damper and boiler. in. of water .in. .in. .in. .in. deg. ..deg. per cent. (a) Draft in main flue near boilers... (b) Draft in main flue between economizer and chimney. (c) Draft in furnaces.. (d) Draft in ash pits.. State of weather. (a) Temperature of external air....... (b) Temperature of air entering ash pit... (c) Relative humidity of air entering ash pit. Quality of Steam Percentage of moisture in steam or number of degrees (17) (b) Steam fed to burner in per cent. of total water evaporated per cent. Factor of evaporation, based on temperature of water entering boilers.... (28) Total equivalent evaporation from and at 212 deg.'.. lb. Hourly Quantities and Rates (a) Oil free from water per cu. ft. of furnace volume per hour....lb. (31) Water evaporated per hour, corrected for quality of steam.... .lb. (a) Steam fed to burners per hour........... .lb. (b) Equivalent evaporation from and at 212 deg. of steam fed to .lb. (32) (33) Equivalent evaporation per hour from and at 212 deg.2. lb. .lb. Capacity (34) Equivalent evaporation per hour from and at 212 deg. Ib. (35) (a) Boiler horsepower developed (line 32 ÷ 341⁄2). Bl. H.P. ....lb. (a) Rated boiler horsepower... Bl. H.P. (36) (37) (38) Percentage of rated capacity developed. - per cent. Wated fed per lb. of fuel oil as fired (item 25 ÷ item 19).................lb. Water evaporated per lb. of water free fuel oil (item 26÷item 21) lb. The term "as fired" means actual conditions, including moisture. 2 The symbol U. E., meaning Units of Evaporation, may be substituted for the expression "Equivalent Evaporation from and at 212 deg." Economy (39) Equivalent evaporation from and at 212 deg. per lb. of fuel oil .lb. (40) Equivalent evaporation from and at 212 deg. per lb. of water .lb. .lb. (b) Net equivalent evaporation from and at 212 deg. per lb. of oil .lb. Calorific Value (42) Calorific value of 1 lb. of fuel oil as received by calorimeter....B.t.u. (a) Calorific value of 1 lb. of water free fuel oil...... .B.t.u. (46) (47) Cost of fuel oil per bbl. of 42 gals. delivered in boiler room...dollars. . dollars. (48) Cost of fuel oil required for evaporating 1000 lb. of water .. dollars. Smoke Data (49) Percentage of smoke as observed..... per cent. (a) Weight of soot per hour obtained from smoke meter. (55) (c) Oxygen (O)..... (d) Nitrogen (N) (g) Water in sample of fuel oil as received..... TABLE 2.-Principal Data and Results of Boiler Test 100 (8) Percentage of moisture in steam or number of degrees of super heating.... (9) Percentage of water in oil. (10) Oil free from water per hour. (11) Oil free from water per hour per burner. per cent. or deg. (12) Equivalent evaporation per hour from and at 212 deg. ft. of heating surface... ..... (14) Rated capacity per hour, from and at 212 deg... (15) Percentage of rated capacity developed. (16) Equivalent evaporation from and at 212 deg. per lb. oil free from per cent. .Ib. . lb. .lb. lb. .lb. per cent. .lb. (17) Net equivalent evaportion from and at 212 deg. per lb. of oil free from water (deducting steam used by burner). per cent. (18) Calorific value of 1 lb. of oil as received, by calorimeter. ... lb. B.t.u .B.t.u. water.... (a) Per cent. of total steam used by burner. CHAPTER XL THE USE OF EVAPORATIVE TESTS IN INCREASING EFFICIENCY OF OIL FIRED BOILERS To the operating engineer it may seem that the somewhat elaborate rules for conducting evaporative tests of steam boilers are of little interest. It is his province to run the boilers as economically as he can, to keep them clean and in proper repair, and above all to keep the plant in continuous operation. There is one very important function of boiler tests, however, which makes them invaluable to the broad-gage operating engineer who is desirous of securing the best possible results from his plant. This is the use of the evaporative test as a guide in determining what is the best furnace arrangement, the best style of oil burner, and the best draft conditions for the particular boilers he is operating. Thus by making a careful test under certain conditions and then making another test, or sometimes a series of tests, under different conditions, it is possible to determine from the relative efficiencies obtained just how the boiler should be operated. It will not be out of place, therefore, to discuss briefly the various changes that may be made in the boiler operation, which when intelligently carried out will lead to higher efficiencies. Furnace Arrangement.-Perhaps the most important part of an oil fired boiler is its furnace arrangement. In a previous chapter a number of different furnaces were described, but it was not stated which was the most efficient. This must be determined by testing the boiler under actual operating conditions, first with one furnace arrangement, then with another, being guided in making changes by the results obtained in the different tests. It is impossible to design a furnace that will be right for all conditions, as with different grades of fuel oil or different makes of boiler or different draft conditions, different furnace arrangements are required. Fortunately it is possible to make minor changes in the furnace very easily, as these involve usually only an alteration of the location of fire brick on the furnace floor. It is thus possible to increase or decrease the size of air openings, or to change them in such a way as to allow more air to enter at one part of the furnace, such as directly under the flame, and less at another part where it is not needed. It is also possible, without much difficulty, to alter a furnace that has been designed for a front shot burner and make it suitable for a back shot burner, and thus it may be found by actual tests which of these two types of furnace is best suited to the particular boiler. In testing the different arrangements it is very important to test the boiler for capacity as well as economy, as it may some Here is shown the furnace interior of an oil fired boiler similar in design to the specifications given in this chapter. Note the V-shaped arrangement in the brickwork in order to admit air for the economic burning of the fuel oil. times happen that the furnace that is most efficient at ordinary loads is not capable of forcing the boiler enough to carry the heavy loads sometimes required. In such a case it may be necessary to adopt a less efficient furnace, as it is usually of supreme importance for the boiler to be capable of carrying an overload when required. Oil Burners.-Boiler tests are of great value in determining what make and style of oil burner is the best to use under the 'given conditions. In testing oil burners it is of extreme importance to measure the steam used by the burner and determine the net efficiency of the boiler; for one kind of burner may produce |