ANTOFAGASTA RAILWAY WATERWORKS. 



129 



are got rid of by hand scraping, each pan having a manhole for 

 access. The bottom di the pan which is of cast iron can be 

 lowered to enable the scale to be taken out. The incrustation 

 is most heavy in the first three pans and these require cleaning 

 every two months. The last three are cleaned out once in three 

 months. The steam pressures and vacua in the pans are as 

 follows : — 



Steam Chest. Vapour from Evaporation. 

 Pan No. 



The ratio of water produced per ton of coal burnt has reached 

 as high as 30 : 1, but this is entirely dependent on the class of 

 coai used. 



Welsh coal gives about 

 Patent fuel (briquettes) 

 Australian coal 



30: 1 

 26: 1 

 23: 1 



Steady firing and careful attention are important factors which 

 will considerably affect the ratio obtained. 



The adjacent port of Mejillones, distant some 70 kilometres 

 from Antofagasta, and which is another coast terminal to the rail- 

 Avay, is not yet supplied with water from the main pipe lines, 

 although a scheme has been approved and the materials ordered 

 for a new main to the port. Two further sets of Fawcett, Preston 

 and Co.'s distillers have been erected there, and have now been 

 under continuous daily work for seven years. They are exactlj^ 

 similar to the Antofagasta sets but a recent change has been 

 instituted whereby the boilers are fired with oil fuel. The system 

 of oil burning employed is the Wallsend-Howden — a pressure jet 

 svstem. The oil from the storage tanks flows to a pump chamber 

 and is pumped through a heating cylinder, heated by means of 

 live steam from the boilers. The oil at varying pressures of 75 

 lbs. to 150 lbs. is fed to the burners, and passing through a dia- 

 phragm inside the nozzle is very finely atomised. The construction 

 of the burner is such that the issuing jet is conical in form, and 

 the heat is therefore applied equally to the whole interior surface 

 of the furnace. The results obtained from the use of oil fuel 

 have been extremely satisfactory, and the ratio of water produced 

 per ton of fuel burnt has increased to 36 : 1 . 



The oil fuel is a residuum oil obtained from California anl 

 has a heat efficiency of 18,000 B.T.U. As the prices of coal and 

 fuel oil in Antofagasta are practically the same, and only two 

 attendants are required for the furnaces where previously eight 

 were employed, the economy is very marked. 



