GAS ENGINEER'S REPORT.

Digger (Invercargill RSA), Issue 30, 8 October 1920, Page 4

GAS ENGINEER'S REPORT.

In accordance with your instructions I have to report having inspected the various systems of vertical retoivts in operation or in course of erection in New Zealand, which meant visiting Christchurch, Wellington, Wanganui, Palmerston North, Napier, Auckland, and Devonport. At Auckland, vertical retorts have been in operation for three years in conjunction with horizontal retorts, and at Devonport, . a branch business- of the Auckland Co., the whole of the gas has.., been made by verticals for six years, the output being about that of our works. At the Miramar works, Wellington, a similar plant has been in operation for over three years, at Wanganui about one half of the supply has been made for over six years by vertical retorts, at Napier the plant is very nearly completed and will displace the horizontal plant now in operation, a\Palmerston North the material is on the site for a similar plant to Napier, and at Christchurch a contract has been let for the first part of a plant that will eventually displace the present one, the foundations being nearly completed and a portion of the plant is on its way from Australia. At ^Wellington, Auckland and /Devonport the system is known as the "Intermittent Vertical Retort," a charge of 12 cwt. of coal being placed in the retort, taking twelve hours to carbonize, and the coke being removed hot in one operation. I couid see nothing to recommend this in coinparison with the continuous retorts, the labour involved being much greater, and in Wellington the extension mentioned is in the continuous system, in preference to the one now in use. At Wanganui, the continuous plant lias been in operation for six years, and has undoubtedly done great work for the Department. Half the gas supplied is made by this plant and half by the same system in use here, and it certainly is most convincing to watch the two plants at work. In the old retort house three men are continually engaged in laborious striking work, in addition to which trimmers and labourers are employed. In the vertical house only one man is employed, whose duties are more fho&e of a mechanic than anything else. This plant was recently repaired after six year's work at a cost of £180, and will continue for some years before further repairs will be necessary. A contract has been let for an extension of this plant, of twice the capacity of the existing one, which on completion will make the whole of the output. The plant at Napier is also on the continuous system,,, having many improvements of the latest design, and it is easy to appreciate their advantages. In each cas.e the responsible engineers are most enthusiastic on the advantages and results from these plants, and it is quite certain that no further extensions of gas plant of any but th,e smallest units "will be made on the old system in New Zealand, all those interested whom I have met being unanimous in their opinions. The control of the quality of gas supplied is made full use of in every case, and my remarks in the report regarding the standard of quality are fully confirmed. The .economy in the cost of operations and the results obtained from these plants excteed my estimates in all cases, and I can only say that I have no reason to amend my figures in any particular, excepting that the percentage of renewal fund might be increased for the purpose of wiping off the capital cost in a shorter period, consequent by reducmg standing charges in the Nfuture. My estimate of the capital cost of a plant suitable for our requirements must also stand, as contracts entered into quite-recently for complete plants coniirm the stated amount. In each case a large portion of the material and machinery is being made in New Zealand and Australia, the portions in which patents are involved being imported. Itis general opinion that prices for this class of plant will- not increase in the future to any great extent. •My experiences and observaffons during my trip of every branch of the gas industry in New Zealand lead me to the conclusion that althongh the coal supply question is a difficult one at present the. future of the industry is assured, as the demand for gas for all purposes is increasing faster than it can be met in most cases. .. Electricity is no longer regarded as a competitor, but as a public necessity, and gas authorities find quite sufficient business in other direetions than lighting and power, and as there is no reason why this should not apply in Invercargill in the future I have no "Hesitation in recoinmending the Council to adopt the mdT't economical methods in our operations and to favourably consider the advisability of adopting the system reported on in thig and my previous report. During my trip I have visited eleven of the principal gasworks, with a cohsequ.-

ent gain in experience in methods of manufacture and administration, the holiday has had the desired effect on my health, and I beg to thank the Council for the leave granted. — Yours 'obediently, (Signed) E. RABBIDGE, Gas Manager. Invercargill, October 7, 1920.