TRANSACTIONS OF SECTION G. 523 



3. On the details of an [Experiment made to Ascertain the Causes of the 

 difference between the Quantity of Seat in Fuel, and the Quantity which 

 is Utilised in the Work done by a Steam Engine. By Emeeson 

 Bainbridge, Assoc. H.C.E. 



The engines of H.M.S. Briton have been represented as types of the most econo- 

 mically worked steam engines of modern times, and the percentage of heat used 

 in doing work in the case of these engines, as recorded by Mr. Bramwell, was 

 ll'l per cent. ; that is, the indicated power of the engines showed a utilisation of 

 11T per cent, of the units of heat contained in the fuel used, this being equivalent 

 to a consumption of 1*8 lbs. of coal per horse-power per hour. If this figure 

 represent the highest result obtained, it will be readily understood how much 

 lower the actual average of utilised power in steam engines constructed and worked 

 in the usual way will be. The difference between 11 per cent, as the proportion of 

 heat utilised which has been proved to be possible, and 5 per cent, which may 

 be, at the most, the average actual percentage utilised in the working of steam 

 engines, suggests a wide field for inquiry and improvement. But a more difficult 

 subject for examination is presented by the difference between such 11 per cent, 

 and the actual heat-power contained by fuel, which is, of course, represented by 

 the figure 100, and whilst a large proportion of the great loss represented by the 

 non-utilisation of such a difference can never be overcome, the importance of the 

 inquiry is evidenced by the fact that every one per cent, gained, means, over the 

 consumption of this country alone, a saving of several millions of tons of coal per 

 annum. 



The result above referred to shows the percentage utilised as proved by the 

 indicating of the cylinders of engines, but does not give the percentage repre- 

 sented by the work done. In the case which the writer now records he has 

 endeavoured to work out the details of the distribution of the heat of fuel in 

 various stages, commencing at its combustion under a boiler, and ending at the actual 

 useful work done by the engine, worked out to units of heat. 



Of the total annual output of coal in this country the quantity actually used 

 in the production of steam amounts to about 50 millions of tons, or about 37 

 per cent, of the whole output, and it is with this appropriation of fuel this paper 

 has specially to deal. 



_ The experiment above referred to was made with the Winding engine and 

 boilers of a small Colliery, such plant being nearly thirty years old, and situated 

 about two miles from Sheffield. This pit is 458 feet deep, and the Coals &c. 

 are raised by a direct-acting Winding engine, to which steam is supplied from 

 two boilers. 



During the time of observations, which extended from July 28 to August 2, in 

 all 184 - 5 hours, the following observations were carefully taken : — 



1. The quality of coal used was the same throughout, and was carefully 

 weighed. 



2. The amount of ash and clinker produced was observed. 



3. The quantity of water passed into the boiler was ascertained by a tested 

 water-meter. 



4. The total number of the revolutions of the engine during the whole period 

 was taken by a counter, the work done by the engine being in each case recorded. 



5. Observations were taken of the temperature of the feed water. 



6. Observations were taken of the temperature of the outside air. 



_ 7. Observations were taken of the temperature of the gases escaping to the 

 chimney. 



8. Observations were taken of the temperature of the outside of the boiler 

 covering. 



9. Observations were also taken of the temperature of the covering on the out- 

 side of the cylinders and steam pipes. 



