ROMANCE OF MACHINES

Timaru Herald, Volume CXLVI, Issue 21380, 24 June 1939, Page 9

ROMANCE OF MACHINES

logued. Their economic life will be from 35 to 50 years. Pipes of a total weight of nearly 4,000 tons have been handled at the yard. Purity Guaranteed Excavations at the headworks were almost completed when the scheme was opened, and since then the actual building of the dam has been finished. The only work now being car-

ried out at the headworks is the construction of the units to house the ingenious apparatus which will ensure the purity of the supply. A radial gate controlled by a float will tend to keep out rubbish and shingle during times of fresh, while special traps will catch silt and sand. An apparatus working on the principle of a photo electric cell, will be trained on the water fed to the distributing system. When the density of the suspended matter reaches a predetermined point, the ray passing through the water will be interrupted and mechanism will be set in motion which will cut off the supply to the pipes. The whole system will then rely on the water in the reservoirs which will be capable of maintaining the supply for several days. When the water clears the turbidity control opens the gates and pure water again

flows into the pipes. This control has been fitted as a convenience and not as a precaution, it is stated. The water is pure at all times from a health point of view, but silt in the water causes domestic inconvenience and it is to guard against this that the turbidity is regulated. From the intake the main line threads over paddocks to Albury

where it runs parallel to the railway line through the township and then follow's the main road to Ma Waro. The ditch in which the pipes are laid has been dug by a powerful chain bucket ditcher capable of cutting a trench two feet wide and several feet deep. This machine, which is proceeded by a bull-dozer which levels the working surface, has now reached Ma Waro. Working at the rate of a quarter of a mile a day it operates like a dredge. Spoil is brought up in the buckets and a conveyor deposits it at the side of the trench. Only two men are required to operate the ditcher, w’hich is Diesel powered. The main pipes have spigot and socket joints and are caulked with molten lead. Water under pressure is then admitted to the completed section and a through test is made.

Any leaks are remedied and the trench filled in. Back filling is accomplished with a bull-dozer—a massive blade approximately 12ft long and 21ft high fitted to the front of a powerful tractor. The blade sweeps the spoil into the trench and the tractor later rolls the surface. This back filling has been completed as far as Albury.

80 Miles of Piping

In the Sutherlands-Pleasant Point area, where 80 miles of galvanised piping has been laid since February, reticulating 17.000 acres, a special threading apparatus had been used. This is similar in principle to a mole drain plough. A frame supported by two huge wheels is drawn behind a 100 horse power tractor with a pulling power of 20.0001b5. Supported by a knife shaped arm which can cut its way into the ground to a depth of two feet, is a torpedo shaped plug to which the pipes are attached. At the rear of the plug a ball and socket device holds the end of the pipe which is lowered into a short ditch and drawn into the ground by the tractor. When the first pipe is almost drawn through another length is screwed on and the process repeated. By this method up to 600 ft of finished piping can be installed in an hour. The tension caused by the drag on the pipes limits the length that can be threaded in this way but pipes from t inch to 31 inches have been successfully laid. Two of these units have been in operation.

The Department has found that a similar device has been used in Chile and it is believed to have been used in the United States. The type used in South Canterbury is new to New Zealand and has been designed to suit local conditions.

The water is to be carried from the dam to seven reservoirs distributed over the reticulated area. The largest of these, which is at Claremont. has a capacity of 1,000,000 gallons. Up to the present both this reservoir, and another at Sutherlands which has a capacity of 240,000 gallons, have been excavated. At Sutherlands trimming work is in progress and the work of lining the reservoir with concrete will commence within a week or two.

To keep the static head within reasonable limits—for the dam at a height of 1,070 ft would give a pressure the pipes could not hold—break pressure tanks are to be installed at various points. These will work on the ball-cock principle.

Contrasting the methods used in the building of the project with those in operation a few years ago, it could be readily seen that the application of the most up-to-date machinery would not only bring the scheme into production in a relatively shorter space of time, but had been a means of removing much of the drudgery associated with pick and shovel work. Men are being trained in the use of machinery which necessitates a deal of thinking on the part of the operator. This fact has not only been responsible for increasing their economic value to the community but has given the men an interest in work which was hitherto regarded as sheer drudgery'. This added responsibility has had the psychological effect of making the men happier in that their worth is no longer assessed in the terms of muscle and bone but more on their mental capacity.