SLAVES OF THE LAMP.

Timaru Herald, Volume XIIC, Issue 13958, 19 July 1909, Page 7

SLAVES OF THE LAMP.

HOW GAS IS MADE. The old saying that one half of the world does not know how the other lialf lives, still fluids good, and the proportion of people who hare even an elementary knowledge of the making or processes through wliich common conveniences of life go, is considerably smaller still. Take gas for instance — a person'turns it on in his house or office, strikes a match, and I'hut! i.«c place is illuminated. It would be safe to bet that not one in a hundred gives more than a passing thought to the intricate process of manufacture that the illuminant goes through before it is in a fit state to light him to his work or play as the case may be, not. to mention the various trades that are kept going on the making of the fittings of all kinds, from gasometers to mantels. Under the able guidance.of Mr W. A. Courtis, the manager of the Timaru Gas Works, who has been connected with Ithc works since 1893, a reporter made a tour of inspection that ■was full of interest and information. The works were first started in 1876, Messrs H. and F. LeCren, Captain Sutter and Wm. Evans being the moving spirits in the scheme, whilst the work of the erection of the buildings and plant were entrusted to Mr ti. Courtis, father of the present manager, and the first manager for the company. Shortly afterwards Mr Courtis', brother, who had helped his fathef with the erection of the works, took over the managership until the year .' 185)3, when Mr W. A. Courtis, the present manager went into office. It will thus be seeu that the Courtis family has liecn intimately connected with the works from their inception, and what Mr Courtis does nut know about; them isn't worth knowing. It is no't .possible, unfortunately, to say that the works have any architectural beauty; perhaps a gas works would be the last place where one would expect-to find anything of the kind, but .;gpjrtamly have a certain grimy ami- -mysterious fascination, and are full of surprises, from the. gloomy recesses of the retort house, where, sweating. slaves of the lamp strenuously lnb'di.r in the fierce and blinding glare of the open retorts, to the great snaky coils of ( the condensers, in the bowels tti which' mysterious processes are going on. . Also there are smells —from the faint ones which make one sniff again to see if they arc really as bad.as one thought they were, to the cropper bottomed No. 0 stenches which make the sniffee light out for tall timber or fresh air. It is a matter for argument whether the site of the works is an. ideal one or no; it is generally laid down that a gas works should >be at the lowest possible point- in a town, and the Timaru works do not comply with that condition. Again, it would be an additional advantage and save cartage if they were right alongside a railway, but on the other hand they are centrallv situated and handy, which is a. consideration when it is remembered that already over 30 miles of gas mains have been laid in the town. ; The coiil from which the gas is made is Westport coal, and as an alternative PelawMain is also used, the average weeklyconsumption ranging from 68 tons during the winter months to about 30 tons in the summer.

A move was made, on Mr Courtis' suggestion, to the retrrt Louse where the coal, which has been carted and tipped through an opening in the building, undergoes its transformation into gas and " by-products. Two distinct classes of retorts are used, those on the southern side being of newer pattern, consisting of three settings of si* 10-foot fire-clay retorts, called D retorts from their sectional shape. The firing of these is rather a complicated arrangement, being what is termed " gaseous firing," as distinct from the firing of the older pattern retorts which is done by the direct method. Besides economising fuel the gaseous firing obtains a higher degree of heat. The charging of a retort is a picturesque operation and well worth watching. The iron door is unlatched, and as it swings back a wave of intense heat causes the too eacer watcher to jump back and shield his face from the scorching gush of gas, and his eyes from the dazzling glare of the incandescent coke. The fireman, wielding a long' iron bar, scrapes out the glowimi mass, that was coal and is now transformed into coke. It falls on an apparatus called a '"butterfly," and is shot straight'/into the furnace below, saving additional handling. The operation of recharging 's then proceeded with. At present charges of 2.V hundredweight of coal are put into each retort, but they will take 3.1 cwt. The coat is brought to within "a convenient distance of tue retorts' mouth in a barrow, and the firemen, armed with a short shovel, flings it in neatly and expeditiously, in a manner which may delude the layman into thinking it is easy, though he will probablv alter his opinion if he tries. Then begins the actual process of gas making. Liberated from the coal by the intense heat in the retort, the gas, full of impurities, passes up an ascension pipe, which leads from the retort. to wat is termed the '"hydraulic main." is a U section pipe partiallv filled with liquor and tar, and in this the first stage of condensation takes place. Then the hot gas passes to the vertical pipe condenser an arrangement of tall iron tubes through which it has to pass and is cooled and at the same time a large proportion of the impurities which consist of tar, ammonia, and other substances are taken out of the gas, the tar running down conduits to the big underground tank in which it is stored.' Another further purification and cooling takes place in the annular condenser, a cylindrical iron" erection

' filled with rings and the gas is brought down to atmospheric temperature in this and more tar and impurities are taken out. From tho annular condenser" the gas is forced through the "scrubber," an iron tank, filled with tiers and layers of boards set on edge, each layer ueing at right angles to the one immediately below and above it. A spray of ammonia liquor is poured in from the top of the scrubber and keeps all. tho boards wet, and when the gas has passed through this process it has lost practically all its tar, ammonia, and a certain proportion of the sulphuretted hydrogen, this latter impurity being a gas with a powerful perfume like unto a particularly rotten egg. The gas is drawn from the retorts anU made to pass through all the cleansing apparatus described'by the action of a Donkin rotary cxJmuster, which sucks it through in volumes which can be nicely, and ingenuously regulated. After passing through _the exhauster the gas is thoroughly washed by being forced through perforated pipes immersed in water, and the last traces of ammonia aro extracted. Then tho much enduring illuminant has to pass through its final purification, in the "•purifiers," which arc large iron tanks 0 feet deep by 10 feet .square in which are layers of" grids covered with oxide of iron, and here the gas looses all ,its sulphuretted hydrogen, and after passing tlirought the big meter which measures it all, it is stored in the gasometer, awaiting its consumption. "A gasmeter is generally considered a fair subject for sneers, but the fact remains." said Mr Courtis," that our meter in the works measures a far larger amount of gas made than is ever accounted for or paid for by consumers, so that, even allowing for leakage, the consumers get the benefit." The three gasometers in which the gas is stored have a capacitv of respectively ] 5,000 cubic feet, 20.000 c.b and 60,000 c.b., a total of 05,000 c.b when all are full, hut with the exception of Saturday nights when the consumption of gas is exceptionally heavy, it is generally found that the, big reservoir holds sufficient, for the needs of tho town and the two smaller ones are kept filled as aTstand by. Approximately speaking, a ton of coal produces about 12,000 cubic feet of pure* gas. From the gasometers the- gas is led through a governor (wliich maintains a constant pressure) and the town mains to the consumers. ~'~- It will not be long now before a large amount of new plant will be imported, and probablv before next winter it will be in working order. These importations will consist of a new. "scrubber by Demnster and Sons, 50 feet high (the present one is only 2-5 feet high) and -with a capacity for dealing with 350,000- cubic feet of gas per day; and a new governor of the latest pattern -made- by Parkinson and Cowan. Sneaking of the disposition of byproducts Mr Courtis said that the Borough Council bought practically all the tar. which was used for street asphalting, while the coke was disposed of-to private consumers, though a good deal' was used in the furnaces at the works. At present no use was made of the waste ammonia, though it had a Teat manurial value for grass lands and green crops. Large gas works mak<T a good deal of money by converting their ammonia wastes into sulphates which are sold as manure.