DISTRIBUTION AND DISTRIBUTORS 305 



entering the central chamber drives the turbine ring attached 

 to the open-trough revolving arms, from one edge of which the 

 sew^age overflows on to the bed through slots graduated in size 

 according to the distance from the centre, with the object of 

 attaining equality of distribution. The troughs have corrugated 

 pendent rims like Stoddart's on their under sides. The quantity 

 of sewage delivered is restricted by regulators or equilibrium- 

 intermitting valves, such as are used by the Company for land 

 irrigation. The distributors are offered in sizes from 15 ft. to 

 100 ft. diam. 



'* Travelling distributors " is the trade term for those which 



Fig. 53. — Travelling Distributor for Rectangular Beds at 

 Wednesbury. 



pass backwards and forwards over a rectangular bed (Fig. 53). 

 They are not of such general application as revolving sprinklers, 

 and are more affected by wind resistance. They can be driven 

 by the recoil from jets, the liquid being automatically made to 

 issue alternately from each side, or can be actuated by other 

 available means, such as by wires worked by a small water- 

 wheel, with reversing arrangements. They are sometimes 

 supported by floats placed in the feed channel. Hartley's 

 (patent 29,203 of 1904) has a travelling syphon, and is worked 

 by wire ropes actuated by independent power. 



III. Distributors with Tippers. 



The Ashtead tippers have already been described (Fig. 29) : 

 in the later form at Caterham and other places they were 

 double V-shaped trays mounted on trunnions and automatically 



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