HYDRO-ELECTRIC POWER.

Taranaki Daily News, 31 May 1924, Page 6

HYDRO-ELECTRIC POWER.

NEW PLYMOUTH WORKS. PROGRESS OF THE REPAIRS. 4 TO FINISH IN A MONTH. No time is being lost in remedying the defect that recently became evident in the short length of tunnel joining the steel piping to the forebay at the New Plymouth hydro-electric works. Al inspection of the work w T as made yesterday by a Daily News reporter, accompanied by Mr. W- H. Cook, the borough engineer, when Mr. Cook expressed the opinion that the repairs should be completed in from three to four weeks’ time.

It will 'be remembered that when the first tunnel was constructed it cracked in several places when the water was turned in. Some of these cracks occurred just behind the forebay, and although a large portion of the tunnel a little further back was replaced by a steel expansion pipe line, the short length of 20 or more feet immediately ’behind the forebay, where the tunnel was covered by a considerable amount of hill, was allowed to remain. Although the reduction in diameter meant loss of power on account of restricted carrying capacity, it was decided to line the tunnel as it was with a further six to nine inches of cement, and this was accordingly done. When the water was run in, however, the pressure proved too great and the new lining cracked in identically the same places as did the old one, and the escaping water oozed out of the side of the hill, carrying a large mass of soil with it. Mr. Cook was asked to procure and install the pipe line necessary to join the existing pipe to the forebay. The first intention was to install a five foot pipe, which is the same diafcneter as that already in existence, but as provision is made alongside the existing line for a second five foot piping when more power is required Inter on, and as Mr. Cook thought it would ’be better to make the new link as large as possible in view of future requirements, he decided to obtain a 7ft. 6in. pipe, which will carry twice the amount of water. A five foot pipe, said Mr. Cook, would provide approximately 3000 horse-power and the longer pipe double that amount. In order to fit the larger pipe into the tunnel, allowance being made for flanges Bft. 2in. in diameter, it was necessary to remove the inner lining of cement. About a dozen men are employed at the present time in removing the inside lining and in digging away the earth on top, on the outside, so that cement may more conveniently be lowered later on. It is hoped the earth will be removed to-day and the rest of the lining in four or five days’ time. The pipes were due to arrive by the Rarawa yesterday morning and will first be handed over to Messrs Rollo and Millar to be accurately fitted. They will then be taken to Mangorei, and instead 4>f being rivetted into position, as is the case -with the existing ones, they will be arc welded under the supervision of Mr. W. H. Huggett, the borough electrical engineer.