THE DUNEDIN GAS WORKS.

Evening Star, Issue 3126, 25 February 1873, Page 2

THE DUNEDIN GAS WORKS.

Those who take an interest in the means whereby our streets, dwellings, and public buildings are artificially lighted will derive considerable pleasure from a visit to the Dunedin Gas Works, toince Mr Geneve r, the present engineer of tho works, entered on his duties, the place has been almost completely changed, and now assumes the appearance of a busines.-;-likc and well ordered establishment. The machinery and appliances, under the old management, are being gradually removed and replaced by plant designed with all the latest improvements. Several new and ingenious additions have already been made, whereby not only a great saving of labor is effected, but the gas-producing capacity of the works is increased, Noticeable among these is an exhauster, manuf wtured by Beal, and worked by a pr» tty G-horse power steam engine. The exhauster has a forcing capacity of (>,OOO feet per hour, and since it was tirst u : ed the averugeqnantityof gas extracted from the coal is something over7,oUo feet per ton, whereas helore it was used tho average yield from the same quality of coal was only about 5,000 feet per ton. Besides working the e? haunter the engine drives several pumps employed in raising water tar from tho tanks &c. The purifying house has not undergone any material change, but it is intended'at an early date to erect a new building, after the design of those recently erected. New purifiers are now' on their way from England, which will take the place of those at present in use The general practice is to use lime in this part of the process of the manufacture, hut MrGencvcr uses oxide of iron mixed with a small proportion of lime, and he is of opinion that this compound is more effective than lime when used in a pure state. A monster metre has recently been erected, which indicates the quantity of gas manufactured, but not the quantity consumed 1 be latter fact is indicated by the depression of the gas-holder. Tho metre was manufactured by Messrs Braidlaw and f-ons, (..ondon, and has the appearance of a huge drum, with golden hoops, and a case containing intricate clock work. fixed at one end, while at the other, two large pipes are {attached — one conveys the gas from tho purifiers, and the other leads to 'he holder. It may bo remarked here, that a new holder is in course of manufacture, and will be erected in a short time. It will be about three tines the size of the one now jp use, and will have a holding capacity equal to 160,000 cqbic feet. One of the most interesting departments of the works is that where the distilling apparatus is erected. Here the raw tar is subjected to manipulation, understood only by chemists, bub U:e result is the production of naptha and other spirits, picric acid, and the many other beautiful and well known dyes extracted from coal. This is a new branch of the works, suggested and established by Mr Genever with every prospect of success. As art and manufacture in the Colonies become developed, the demand for these dyes will increase, while the manufacturers will !>■ saved the necessity of sending money abroad to procure them, Aa yet, the product of this department, so far as the dyes are concerned, has not been introduced to the public, Mr (leuever, however, has proved that they can bo produced within our midst at a cheap rate ; it thertf ire only remains for the manufacture to be encouraged in order tomake it a success. The tar, pitch, and spirits produped in this department find a ready market, and form a considerable portion of the levenue of the jestaWiphpient. The testing room is a peculiarly interesting place. Here a most delicately constructs! instrument called a photometer is erected. By it the operator is '"enabled to ascerrain the exact lighting quality of the gas. There is another instrument which also enables Inin to discover the quantities of sulphuric acid and other impurities contained in the lighting medi m. There are djfch’er‘instruments of peculiar form, thq gap of whjch is know# only to the initiated. Tiro retort hopse is now undergo ng a complete change, Nsw retorts, designed by tlie engineer, are la aoqrsp of erection. They will take the place of those now in use. When completed it is expected that a great oavipg will be effected in the working of this department. The retorts proper are made of clay, because they last longer when worked with the exhauster than iron retorts, In a word, the works even in their present condition reflect great credit on the engineer. The intelligence, knowledge, and attention to details displayed, are observable everywhere, while the good order and cleanliness of the establishment gives it a pleasing appearance not generally characteristic of such places. |