128 AM'OFAGASTA RAILWAY WATERWORKS. 



The old rails intended for the floor were dispensed with as a 

 good rock foundation was encountered. Instead of using rails 

 for the reinforcement of the columns, four 1 inch steel bars set at 

 10 inch centres were used, and wrapped round with No. 8 L.W.G. 

 steel wire at intervals of 9 inches. The interiors of the reservoir 

 and the columns were rendered with f inch of cement and sand 

 in equal proportions. 



The valve house has been erected with a view to placing the 

 Pelton wheel on the roof of the reservoir, and installing the 

 electric plant in the upper storey of the building, but as yet this 

 part of the scheme is in abeyance pending more favourable time 

 for capital expenditure. 



The valves in the valve house are worked by means of head- 

 stocks, and the high pressure valves on the inlet main are pro- 

 vided with 3 inch bye-passes. 



Water Distillers. 



In 1905 the Company decided to instal two sets of water 

 distillers in Antofagasta in order to act as a safeguard in case 

 of serious accident to the main pipe line, which would have left 

 the town absolutely without water. Two sextuple sets of Messrs. 

 Fawcett. Preston and Co.'s distillers were obtained, each with 

 a capacity of 44,000 gallons per day. 



These are erected on the sea shore about three miles south 

 of the town. Each set consists of six evaporators, heater, con- 

 denser and pumping engine, and there are three Lancashire 

 boilers, 8 feet in diameter and 30 feet long, common to the 

 two sets. 



The pumping engine carries the air pump, two circulating 

 pumps, the distilled water discharge pump, and the brine dis- 

 charge pump for withdrawing the brine from the pans. 



The evaporators consist of steel drums, 6 feet 6 inches dia- 

 meter and 12 feet high. The lower part of the drum contains 

 a steam chest with vertical copper tubes. 



Salt water from the main condenser is passed through a 

 Green's economiser and is admitted to the first evaporator pan. 

 Exhaust steam from the pumping engine at 9 lbs. pressure is 

 passed to the steam chest around the condenser tubes in the 

 lower portion of the pan. Part of the salt water is thus evaporated 

 and the steam raised (which has a pressure of about 6 lbs.) 

 passes to the steam chest of pan 2. The salt water having in- 

 creased in temperature is also fed into the evaporation chamber 

 of this pan, and again partially converted into steam. This 

 process is repeated throughout the set, and the concentrated 

 brine in the last pan is discharged through the brine pump. The 

 condensations from the steam chests of the first three pans are 

 led back to the boiler feed, whilst the condensation from the last 

 three pans pass to the main condenser. A complete system of 

 bye-passes on all pipes and mains enables any pan to be cut out 

 of the set for cleaning without necessitating the stoppage of the 

 whole plant. The incrustations in the tubes of the evaporators 



