The Evening Star WEDNESDAY, FEBRUARY 18 1874

Evening Star, Issue 3430, 18 February 1874, Page 2

The Evening Star WEDNESDAY, FEBRUARY 18 1874

Some months ago attention was directed to a plan for burning the brown coal of Otago in furnaces so constructed as to prevent waste of fuel and to ensure complete combustion. The subject has passed out of notice, as almost all topics do that do not immediately bear upon general interest j and probably only a few, specially concerned, continue to think over the matter. Yet it is one that should not be forgotten, for on the adaptation of our coal to manufacturing purposes depends much of the future prosperity of the Province. It will be recollected that the object sought to be attained was a furnace with grate bars so arranged, and the draught so regulated as to get lid of the ashes and prevent the coal dropping through the grate before perfect combustion had taken place. Precisely similar objects have been sought at Horae, together with a means of consuming smoke, and we have been favored with a copy of the weekly number of ‘ Iron,’ published on November 1 of last year, containing an account of T. Yicars’s self-stoking, smokeless furnace, which is pronounced “ simple in construction and efficient in operation.” The writer of the article points out that “smoke” is not only a nuisance but waste, and that it is necessary to true economy to U P* He remarks “ the gradual rise in the price of fuel ” having stimulated the production of smoke-prevent-ing contrivances, English manufacturers may soon be placed in a similar position with their Belgian brethren, who “ find they cannot afiord to make smoke, and annoy their neighbors, at great expense to themselves. The human stoker should theoretically be

perfect, seeing that he has, or is supposed to have a considerable amount of intelligence to guide him 3 but, iu practice, it is found preferable to expend intelligence upon the production of a mechanical stoker, which shall regulate both the supply of fuel and the quantity of it undergoing combustion in the fire.” “Intelligence ” having been directed to this, the result has been that Messrs V icars have arranged a furnace so that by regularly feeding it at the mouth with small coal, the whole of the burning fuel, as combustion proceeds, is carried “ hy easy movements of two or three inches at a time '* towards the further end of the fire-place. This movement is not effected by an endless grate band, but by a motion which seems to have been suggested by the peristaltic movement of the alimentary canal 3 as it in some respects resembles it, being a “ backward and forward motion of the fire bars.” « These bars are acted upon by plungers, which carry them forward together with their layer of coal on the top, and then, an eccentric Dt.iig applied, every third bar in the series is brought back to receive a fresh supply. In this systematic and continuous way the furnace is fed with coal, which passes through in slow and easy stages, the same quantity of fuel being at all times in exactly the same state.” The bars are set close because the coal is small 3 combustion is perfect, the smoke is burnt up, and the waste fuel is discharged in the form of clinker or slag into the ash-pot at the far end of the grate, which, in this invention is a pan of water. “On dragging out some of the ashes,” the writer of the article found them perfectly free from admixture with unburnt coal, “ while from the stalk (chimney), into which the flues from several of the furnaces are led, a small wreath of smoke emerges no larger than, if as large as that from a common domestic chimney.” After thus describing the economy of fuel secured by Messrs Vicars’ arrangement, the question is considered whether it is worth while for manufacturers to incur the expense of a smokeless furnace. The calculation illustrating this point is one that gives us iu the Colonies a glimpse of the enormous consumption of coal in some of the manufactories of Great Britain. After stating that the saving of fuel when “ round coal” is used is 20 to 25 per cent, and if dross 15 per cent, the supposition ’is the cost of daily supply for a factory “ having 25 boilers of 40-horse power each, and consuming 100 tons of coal.” Estimating this at 15s a ton, the daily cost will be £75, or ,£450 a week of six working days. For firing under the present system 13 stokers will be required at 22s a week of six working days, or £l4 6s per week in all, giving a total for coal and labor of £464 6s a week. The saving in coal by the use of Vicars’ furnaces, being at the rate of 20 per cent,, will be £9O per week, and labor being diminished to the extent of a fourth, the saving in wages may be given as £3 10s, or a total weekly saving of £93 10s. Fifty working weeks at £93 10s gives an annual saving of £4,675. The cost of erecting 25 Vicars’ furnaces, at £l5O each, is L 3,750, or less than the survey during the first year of their use by £920. It appears, from a further paragraph, that the cost of repairs is light. The fire-grate bars are the parts subjected to the greatest wear, but being partly immersed in water troughs, they are kept cool enough to ensure their preservation for a length of time. A small donkey-engine, of 4-horse power, is sufficient to work sixteen furnaces. We do not know whether this invention can be adapted to our brown coals or not. Possibly Colonial ingenuity may see in it something that may be useful. At any rate it points to the direction investigation should take, for we have little doubt there is a dormant power in Otago, that, developed, will place it in the world’s front as a manufacturing Province.