The Scoop Wheel. 77 



provided with a proper adjusting shuttle may be run with a 

 greater speed than with flat scoops, as the water escapes off 

 the scoops more readily, and will work effectively if run at a 

 speed at the periphery of 9 feet per second. Curved wheels 

 may also be made of less diameter than those having straight 

 scoops. Wheels with curved scoops are in use at Zuidplas, 

 Waterland, and other stations in Holland, for the Upwell and 

 Outwell district in the river Ouse, and at Ravensfleet and 

 Sturton on the Trent. 



The older wheels made in Italy had the scoops straight 

 and radial. These wheels were of low efficiency, dashing the 

 water about as each scoop entered and left the water. More 

 recently, the practice of some of the Italian engineers has 

 been to make the wheels of iron, the scoops being inclined at 

 about 60 degrees to the radius, and formed with a double 

 curvature, a sliding iron shuttle being provided so as to admit 

 the water to the lower part of the wheel only.* At Gouda, 

 some of the scoop wheels erected in 1857 were subsequently 

 changed to wheels having curves with the concavity towards 

 the outer water, one having the concavity towards the inner 

 water, and two with the scoops nearly flat. The difference 

 in the delivery of these wheels was slight, the first-named 

 giving, on the whole, the best result. These have since all 

 been changed to fiat scoops. As a matter of experience, 

 wheels with flat scoops give the best results when all circum- 

 stances are taken into consideration. 



The inlet and outlet courses for the water are constructed 

 of masonry, the wall of the engine-house generally being 

 placed on the inner side and the shafting from the engine 

 passing through an opening. The practice in Holland is 

 generally to decrease the width of the raceway as it 

 approaches the centre of the wheel, the sides converging at 

 an angle of 17 degrees from the straight line, the raceway 

 at its widest part being about one-third wider than the 



* Trans. Inst. C E , vol Ixxvi., p 402. 



