TRANSACriO>rs OF THE SECriOXS. 217 



cannot intercept and utilize all the heat which is produced, no inconsiderable 



Eortion of which escapes into the waste-flue, and thence to the chimney. This 

 eat should be intercepted and utilized by a series of pipes placed in the flue, so 

 that the minimutu quantity may find its way to the chimney. Wrought-iron 

 steam-tubing is the best for this purpose ; it will stand a g-reat pressure, and the 

 metal being thin, the waste heat is at once communicated to the feed-water inside 

 the pipes ; and, further, wrought-iron pipes do not incur much liability to fracture 

 on account of alternating temperature, or from any uncertain or ■\iolent action of 

 the pumps, or misadventure from other causes. 



In thus endeavouring to utilize fuel to the utmost, other difficulties present 

 themselves. The chimney-draft is produced by hot air ; and if this heat is arrested, 

 chilled, and absorbed by coming into, contact with obstacles in the shape of pipes, 

 the surfaces of which are kept comparatively cold by the feed-water inside, the 

 chimney-draft is correspondingly diminished and injured; and if the heat were 

 altogether absorbed, there would be no chimney-draft at all ; therefore, in many 

 cases, the injury to the di-aft is the direct measure of the utility of the appliances 

 for the absorption of the waste heat. In this contingency it is well to have recourse 

 to the fan-blast to improve the draft, and thus to supply the requisite quantity of 

 oxygen by mechanical means. 



I have learnt from experience that machine firing with the aid of the fan-blast is 

 the most effective. The fuel is supplied continuously, ignition is more regular and 

 intense, and the chill and consequent destruction of heat caused by frequently 

 opening the furnace-doors is avoided. Steam is raised with a greater certainty 

 and at less cost both in fuel and wages by this mode of. firing. There is also an 

 economy in grate-bars, and greater facility in preventing and consuming smoke. 

 To assist the fireman in preventing smoke, it is well to have a reflector of plate 

 glass fixed in some convenient place outside the building, so that he may see at any 

 moment and at a glance how the chimney top is behaving. No eificient work can 

 be performed without good tools, and these in return require the care and watchful 

 intelligence of the workman. 



We cannot economize fuel to the utmost without proportionately diminishing the 

 power of the boiler as a generator of steam. If the boiler be furiously fired without 

 any regard to economy in fuel, all other things being equal, more steam will be 

 raised, thougli at a greater cost, than if the firing were done carefully. If the heat 

 be extracted to the utmost possible extent, the boiler of necessity does less work, 

 and the steam raised is less in quantity ; and a similar fact appears in the economical 

 utilization of steam in the steam-engine. In the boiler, as in the engine, conflicting 

 conditions arise, that whilst we seek to satisfy the one, we of necessitj' sacrifice the 

 other. In the production of heat it may also be borne in mind that the engine is a 

 valuable adjunct to the boiler, to which it may be made to restore a portion of its 

 waste heat, which has already done its work as a motive power. 



The Economical Utilization of Steam. Bij Robert Sutcliffe. 



The primary object which the steam-engine has to secure in spinning- and 

 weaving-mills'is extreme regularity and steadiness of motion ; compared with this 

 economy in fuel, important though it be, is a subordinate consideration. Thus, 

 whilst theory tells us to use one engine only with enlarged cylinder area, a pair of 

 engines working at right angles give a steadiness of motion and equability of 

 pressure unattainable in the other case ; hence the pair is adopted, and the theo- 

 retical advantages of a single engine are discarded. When steam is used at a high 

 degree of expansion with a single engine, the irregularity of motion is in many 

 cases painfully apparent. AVeight and velocity in the fly-wheel may diminish 

 the defect, but cannot entirely neutralize it; but with a pair of engines we can 

 work with high expansion combined with great steadiness of motion. Where 

 steadiness of motion is not of primary importance, economy in fuel may be the 

 first consideration. In this case we may work with a single engine with steam 

 ut upon the piston at high pressure, cut olF early in the stroke and wrought to a 

 igh degree of expansionr 13ut here our finest calculations are rudely interrupted 

 1873. 15 



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