LAKE COLERIDGE POWER.

Star (Christchurch), Issue 16319, 7 January 1921, Page 7

LAKE COLERIDGE POWER.

A VISITOR’S IMPRESSIONS,

SILT AND THE TURBINES. Some interesting observations on the Lake Coleridge hydro-electric works were made by Mr E. Philpot Crowther, hydro-electric engineer, of Sydney, who is on a visit to New Zealand. Air Orowther recently visited th© lake and powerhouse. In conversation with a representative of the “-Star ” he put forward r» susgestion which may be of value. The cause of much trouble at the powerhouse, said Mr Orowther, was the wear on the turbines caused by tho gravel and silt which passed through iho tunnel and pipe lino- from the lake. The screens and surge chamber caught a certain quantity, but they did not entirely eliminate the solid material, or ensure that nothing but water entered tho The result was that the blades of the turbines wore worn by grit or silt, with a consequent loss in power and efficiency. Mr Orowther’s suggestion was that a tower should I>e placed in the lake, in deep, water, and the t-annei extended by means of *» pipe line to connect with it. The pipe would be carried down the tower into the deep water, and so draw the supply from a portion of the lake which was entirely free of gravel or silt. He was speaking without a knowledge of the contour of the lake, and it was possible that the depth 1 might be too great for the tower to bo [ a practicable proposition. J.n that case, however, tho tunnel pipe could bo carried out, and supported in deep water on tho cantilever principle. He was strongly cf opinion that the gravel and silt would only be effectively shut out when tho water lor the turbines was drawn from deep pure water, which wo'ild be free from the disturbances which were apparent at the intake. Tho wpar and tear caused by silt and on the turbines must be severe - ho had seen that, for himself when ho inspected one of the tilrbincs at tho powerhouse—- and the task of effecting repairs would bo both expensive and laborious. The tower system had boon adopted in many hydro-electric and water supply undertakings, whore the purity of the water was an essential, and he believed that it could be used profitably i;i connection with Lake Coleridge.