336 NOTES ON DOCKS AND DOCK CONSTRUCTION. 



admit of the fans being changed or examined without difficulty. 

 The discharge and suction-pipes are each 38 inches in diameter ; 

 the lower end of the suction-pipes being enlarged by a trumpet 

 mouth to 60 inches. 



These pumps are so arranged that, by means of suitable 

 clutches, either fan can be disconnected from the engine-shaft, 

 when they are not required to be working together. 



Suction Culvert from 

 Main //V// to />r<ti>i<t.:.'e ll'tit. 



No foot- valves are employed on account of the trouble they 

 give ; but a sluice is fitted to the outlet branch of each pump. 

 When this valve is closed, a steam-ejector, which is fixed to the 

 top of each casing, charges the pump in a minute or two. 



These pumps are capable of clearing about 50,000 tons of 

 water in four hours ; the total lift at the close being 36 feet. 



The supplementary engine for driving the air- and drainage- 



