THE DRAINAGE PUMPING STATION.

Otago Witness, Issue 2675, 21 June 1905, Page 89

THE DRAINAGE PUMPING STATION.

EXHIBITION TRIAL OF THE DIESEL ENGINES. „ At the invitation of the chairman of the Drainage Board a large number of city gentlemen and representatives of various local bodies visited tho board's pumping station at Musselburgh on Saturday afternoon to witness the exhibition trial run of the powerful Diesel engines installed at the station. The Drainage Board, the City Council, Harbour Board, Dock Trust, Port Chalmers Borough Council, Roslyn, Mornington, and St. liilda Borough Councils, and many leading- business firms were represented. The visitors were met by Mr J. T. Noble Anderson (the Drainage Board engineer) and Mr Peter (the Diesel engine expert), but otherwise no ceremony or function of any kind took place The Diesel engines were imported for the Drainage Board by Messrs Ross and Glendining, and, in accordance with the terms of that agreement, if the fuel consumption of the engines exceeded a certain limit, the company had to pay liquidated damages, while if the economy was such that lie fuel consumption was below a certain limit the Drainase Board paid an equivalent bonus. On May 30 Mr Anderson, after testing the engines, reported to tho board: "The net result is equivalent to a saving of 3ilb of oil on each engine, less than the standard of 501b per hour v. hich was fixed for the bonus, or a saving in all of 6glb of oil as the result of the complete set of trials of both engines." Thus the two engines, of 120 brake horse-power each have exceeded the maker's guarantee in point of efficiency and economy in working. With the two engines and the Gwynnes pumps the station is oapable of pumping 36,000,000 to 37.000,000 gallons a day, and when the third pump is installed with the electric motor the capacity of the station will be 55,000,000 gallons per diem ; these are, of course, the maximum capacities. In the ordinary working the station will not require to run more than one out of the three units. In about six to eight hours' pumping the machinery can dispose of the sewage from a population of 70.000 or 80,000 people, so that it will be some time before more than one skilled man will require to be on duty at the station. Saturday was the first occasion on which both pumps were working together. Up till then the pumps and engines had been tested singly. The water for the tests on Saturday was introduced from the harbour at two places. The first was at Macandrew road ; the old Maca-ndTew road sewer outlet had been turned into the main intercepting sewer, and the tide, through a 3ft diameter opening, was pouring into it. The other opening was beside Anderson's Bay road, where the old outlet for the tide, situa-ted beside the PortobeUo road, had been opened, and a stream of water, about 7ft wi^ by nearly 3ft deep, was flowing into the sewer. Tlie sewer is sft 6in in diameter until it reaches the tank. At the tank it discharges by a 30in pipe into the tank, and at the same time passes one. of tho walls of tbe tank by a covered by-pass, which is 7ft high and 4ft 6in wide. The settling tank and by-pass both discharge into the suction well, which is 40ft long by 10ft wide by nearly 20ft deep. From the well each pump draws the water. On leaving the engine-house tbe water is discharged by means of two 3ft diameter rising mains ; one of these rises to a level of about. 10ft, and the other rises to 6ft above high tide, and at these levels discharge into what is known as the dividing well, situated on the Domain Board road at Tahuna Park. The higher level is then continued by a sewer sft wide by 2ft Bin deep to the ultimate sewer outlet at Tomahawk Head. The work of this has up till now been only completed as far as Lawyer's Head ; and at the termination of the completed part of this sewer a connection has been made so that it could discharge into the lower level sewer, which carries the storm water from the other rising main to the storm water outlet at Lawyer's Head. During the trials on Saturday a cab was kept running between the station and the outlet to enable the visitors to se« the discharge. Tho running commenced a few minutes before 3 o'clock, and instructions had been given to the workmen to close off the tidal entrances at 4 o'clock, that being the estimated period of hig-h tide. While the academic result of the Diesel engines is 79 per cent, of mechanical efficiency, Mr Peter, the expert, has succeeded in obtaining 81 per cent.

Mr D. R. Eunson, New Zealand agent for tbe Diesel engines, who was present at the exhibition trial run, gave some interesting particulars about the engines to a representative of this journal. Mr Eunson said the Diesel engine was the invention of Herr Rudolph Diesel, and it had complied with the most exhaustive tests in every particular, and Lord Kelvin's report was evidence of general excellence where he said that " Diesel had actually obtained 58 per cent, more work than any that had been given, from the same weight of oil, by any of the best oil engines previously made." In the very exoellent workmanship of the parts of the engines, whioh reflected the utmost credit upon the makers (Messrs Sulzers, of Winfcerthur), the acknowledged skill exercised by their representative (Mr Peter) in the erection of the plant, and the eminently satisfactory fulfilment of all its guarantees by the Diesel Engine Company, there was, he thought, every reason for congratulation to the Drainage Board in having become custodian of a most efficient and economical power plant. The Diesel was an internal combustion, not an explosion, engine, and was efficient and economical in working. Since 1898 over 1200 engines, of over 75,000 brake horse-power aggregate, had been installed, and numerous orders for engines of powers varying from eight to 1000 b.h.p. were being" executed. The combustion of the Diesel engine was perfect, and the exhaust was clean and free from enieli and unburnt gases. The consumption of fuel was less than £lb per hour of crude or other oil pct 1 b.h.p., varying from 0.4-lb in the larger sizes to 0.491b in the smaller. The Diesel was not dependent upon refined oil, as it could be run with crude oil. There was no flame ov igniter, hot tube or electrio spark used for ignition, and therefore no danger of fir©. The thermal efficiency of the Diesel engine was represent^ by 41 per cent., while that of a steam engine was 20 par cent., that of the oil engine (explosive type) 20 per cent., and that of a gas engine 30 per cent. The engines and pumps were kept working till about 5 o'clock, and the result of tho trial £iin was satisfactory, jn, every