141 — REPORT ly.

PUMPING MACHINERY AND ENGINE TESTS.

G. E. PENNINGTON, Superintendent Engineer.

The primary object of this report will be to show the working and test performances of each pumping unit employed in connection with the work of the Central Research Farm and its relative suitability for general adoption.

Boiler, engine and pump tests have been made with each plant, and the results obtained will be found in tabulated form.

The early history of the farm was one of unceasing effort to maintain connection with the river and ensure continuity of the water supply, which was repeatedly threatened by shifting sand banks. Reliability rather than economy was consequently sought in the machinery selected.

The transfer of the farm to the Education Department in 1912 coincided with the final isolation of the central pumping station from the river by a large and permanent sand bank, when a new site was selected 1,400 metres to the north and floating pumps adopted as a solution of the sand-bank problem.

At the earliest opportunity engines of a more modern and efficient type superseded those originally installed, and a marked reduction in running costs was effected.

The benefits subsequently obtained were, however, lost for a season by the sinking in transit of a new 18-inch pumping plant with its pontoon by a hurricane. Recovered some seven months later, the unit was ultimately erected, and its performance is described in the body of the report. Happily it suffered little or nothing from submersion.

The decision to irrigate native-owned lands in the vicinity of the farm and on Tuti Island, involved the purchase of additional plant and a strengthening of the staff for the supervision of pumping stations and the distribution of water.

Wood being the only available local fuel, has been used in all steam boilers at a cost of 500 milliemes (10s. 3d.) per ton, and a saving of 46 per cent, has been effected on earlier running costs with imported coal purchased at £E.3 per ton.

This reduction might have been further extended by the employment of fire-boxes specially designed for wood fuel, but use had to be made of boilers already on hand.