Three Reports on the Use of the Steam Coals of the "Hartley District" of Northumberland in Marine Boilers

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Page 13 - The next plan submitted to trial was that of Messrs. Hobson and Hopkinson, of Huddersfield. In this system air is admitted both at the doors and at the bridge. At the doors by means of vertical slits, which may be opened or shut at will by a sliding shutter, and at the bridge through apertures in hollow brick pillars placed immediately behind it. The entrance of the air to these pillars is regulated by throttle valves, worked by a lever in the ash-pit. There are also masses of brickwork placed in...
Page 16 - Its peculiarity consists in the adoption of a shelf outside the boiler, forming, in fact, a continuation of the dead plate outwards. Upon this shelf the fresh charge of coals is laid in a large heap, about half of the heap being within the furnace, and the rest outside. The door is a sliding frame, which shuts down upon the top of this heap of coals, so that air is admitted through the body of the coals as well as through perforations in the front plate of the furnace. When the furnace requires fresh...
Page 6 - ... the draught and rendering the prevention of smoke somewhat more difficult, whilst, at the same time, it slightly increased the evaporative effect by its additional absorbing surface. This increase was, however, much less than might have been expected from the large absorbing surface of the heater, which contained 320 square feet ; yet it was found that, when the products of combustion before entering the heater were at 600°, the passage through it did not reduce the temperature more than about...
Page 15 - The system is applicable to all the usual forms of boilers, the combustion is very good, and, with moderate firing, it does not much depend upon the stoker, and we are therefore of opinion that it complies with all the prescribed conditions. The next plan tried was that of Mr. C. Wye Williams, of Liverpool. Mr. Williams...
Page 13 - ... the ash-pit. There are also masses of brickwork placed in the flame-chamber, with the intention partly of deflecting the currents of gases, so as to ensure their mixture with the air, and partly to equalise the temperature. As regards prevention of smoke, we have to report that this plan was very efficient, though in hard firing it required considerable attention from the stoker. Whilst burning about 15 Ibs. of coal per square foot of grate per hour, no smoke was visible, even with ordinary firing,...
Page 12 - ... value of fuel and work done, the following was the result : — Economic value of fuel .... 10-70 Ibs. Rate of combustion ... . . 15-50 „ Rate of evaporation per square foot per hour 2'14 cubic feet. Total evaporation from 60° ditto . . 70'50 „ Comparing these results with the standard, we get From this it appears that though there was an increase of economic value of fuel to the extent of 137 per cent., there was a loss of work done by the boiler to the extent of 5'8 per cent., and this,...
Page 14 - From these tables it appears that with the large fire-grate there was an increase of economic value of fuel, although less work was done ; whilst with the small grates there was a decided increase both of economic value and of work. Had the fires been harder pushed with the large grate, we have no reason to doubt that, although the economic value would have been somewhat less, the work done would have been up to the standard. The only objection to this system is that the brickwork is liable to crack...
Page 8 - As the economic effect of the fuel increases when the ratio of the fire-grate surface to the absorbing surface is diminished, we have adopted two sizes of fire-grates, and consequently two standards of reference. With the larger fire-grate the amount of work done by the boiler per hour is greatest, but this is done at a relative loss of economic value of the fuel as compared with the smaller grate. The one gives us the standard of maximum evaporative power of boiler, — the other the standard of...
Page 6 - ... important question which we had to decide, inasmuch as one of the principal conditions established for the competition was, that the plans submitted should not diminish the evaporative power of the boiler. It was, therefore, our first object to ascertain this evaporative power as a standard of reference. The boiler built for these experiments presented no peculiar features. The annexed drawing will show that it was the ordinary type of a marine multitubular boiler, such as is generally considered...
Page 6 - ... of the trials. 6. The premium shall be paid over to the inventor of the design which, in the opinion of the majority of the judges, shall be entitled thereto. 7. No design shall be deemed entitled to the premium, unless it be in conformity with the following conditions...

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