6 BULLETIN 147, U. S. DEPARTMENT OF AGRICULTURE. 



three-quarters of an hour, with the result that the combustible gases 

 in the coal were distilled and escaped unconsumed up the chimney. 

 Finally, holes were burned in the fire bed so that too much air was 

 -allowed to pass through, which cooled the boiler and setting and also 

 carried a large part of the heat up the stack. 



The average quantity of coal per 1,000 pounds of butter made of 

 all creameries studied was 1,140 pounds, though many of them pro- 

 duced 1,000 pounds of butter with a fuel consumption considerably 

 les- than 4-00 pounds. 



The total quantity of factory-made butter in the United States, as 

 reported by the Thirteenth Census (1910), was 627,145,865 pounds. 

 If the quantity of coal were reduced to, say, 400 pounds per 1,000 

 pounds of butter, the saving would approximate 232,000 tons annually 

 in the creameries throughout the country, which at $5 a ton would 

 amount to $1,160,000. 



CONSTRUCTION OF BOILER SETTINGS. 



In comparing and studying the itemized expense reports of a large 

 number of creameries it was noted that in most cases the fuel item 

 was excessive. It was extremely variable even in creameries which 

 made practically the same quantity of butter annually. Further in- 

 vestigations showed that this wide 'variation in the fuel consumed 

 was due largely to one or more of the following causes: (1) Poor 

 installation and maintenance of boilers and settings; (2) careless 

 firing; (3) bad condition of engine and other steanirdriven machin- 

 ery ; (1) failure to utilize the heat in the exhaust steam; and (5) lack 

 of system in operating the plant. 



A common cause of fuel loss in the average creamery is faulty 

 boiler setting. Most creamery boilers in use at the present time are 

 of the horizontal return-tubular type and require an external setting 

 which is generally constructed of brick. The settings are usually 

 built by local workmen who have had little or no experience in boiler 

 work ; hence the construction is nearly always too light and flimsy to 

 withstand the heat and the weight of the boiler and contained water. 

 As a result the settings crack from the heat and weight and thus 

 allow too much air to enter the furnace. This reduces the draft 

 and also causes a direct heat loss, due to the heating of excess air. 



Warped and cracked firing doors also contribute to the heat loss 

 by admitting more air into the furnace than is required for complete 

 combustion- The economical burning of fuel requires not only the 

 proper arrangement and proportioning of the furnace, combustion 

 chamber, uptakes, breeching, and chimney, but also that they be 

 practically air-tight. To burn fuel completely a definite quantity 

 of air is required, which must be admitted at the proper place and 

 time and be mixed thoroughly with the combustible gases. 



