CONSOLIDATION LOCOMOTIVES.
59
0 n the ring will always run a little beyond the point C on the valve-chestcover, and similarly the point D on the ring will always over-ride the point& on the cover. Thus no ridge can be formed on the ring or cover. Atight sliding joint is made between the balance-ring and the body of theVa lve by a plain cast-iron packing-ring sprung into a groove cut in thevalve. Fig . i is a longitudinal section of the valve, fig. 2 is a plan of theraised working face on the steam-chest cover, fig. 3 ' s a half cross-section°f the valve, and fig. 4 contains two views of the balance-ring. If theinner extension of the ring were not perforated as shown, the film of steambetween the ring and the steam-chest cover would force the ring down-ward and off its face ; the pressure on the upper surface of the ring acting°n a larger area than that outside the packing-ring exposed to upwardPressure. The area of the upper portion is therefore diminished by numer-°us i n _ holes, so that the ring has no tendency to fall off the face whenste am is on.
Much trouble is often experienced in casting the Allen form of valve,as it has been found especially difficult to vent the core forming the main
Netting 2'/2Mesh.N? 13 Wire.
_Over Frame 5 i__
Fig. 295.
Extended Smokc-box and Hopper .
Tip ^ °f the valve, gas collecting and forming spongy places at A, A, fig. 1.co/ S tr ° U ' :i ^ e bas been avoided at Louisville by making this a green sandCr ^ 6 ’ an< ^ Ven ti n g it through a large aperture going completely through thej n °f the valve. This is afterward drilled out, and a piece of brass tube“ted into the hole and the ends of the tubes riveted over. The in-na passage is formed with a dry sand core.v . hopper in the bottom of the smoke-box is fitted with a brass slide-of t, 6 ' can be moved by a hand-wheel and screw. The valve seat is
r ass cast with the hopper, which is of cast iron. It is found that theUre ar| d sulphur in the ashes corrode a cast-iron valve-seat and rendermcult to move the valve. The construction of this hopper and valve isy shown in the cross section of the extended smoke-box, fig, 295.w , . ^he engines are painted with iron oxide paint of a rich brown color,* f C lo °ks well. No difficulty is found in getting this paint to a smoothTh Ce> ' s a complaint sometimes brought against iron oxide paints.
th c °l°r, however, has not proved so durable as in paints with a lead basis,4. allowing for the difference in first cost, the iron oxide paint appears° be the cheaper.
1 ne principal dimensions of the engine are as follows :
Cyhnders, -
^‘ameter of drivers, -
\y a . Ct ' ve force per lb. average pressure on pistons,ei ght in working order,
20 in. x 24 in.51 in.188.2 lbs.iii,ooo lbs.
CONSOLIDATION LOCOMOTIVE.
well, who was then the Superintendent of Motive Power of the Norfolk &Western.
The engine we now illustrate was built by the Roanoke Machine Worksfrom drawings and specifications prepared by Mr. Blackwell, after the Bald-win engines had been at work some little time. Such alterations and im-provements in design as running experience showed to be advisable aretherefore embodied in the engine shown in the accompanying illustrations.
The modifications thus introduced on the ordinary type of Consolidationhave been chiefly directed to promote economy of fuel. The fire-box hasbeen placed above the frames, giving a larger grate area. The saddle-platehas been made deeper, giving a greater distance between the top of thegrate-bars and the under side of the brick arch. This tends to equalize theaction of the draft on the fire, and gives more space for the mixture of thegases beneath the brick arch.
The steam-pipes and steam passages in the saddle have also been en-larged so as to diminish the loss of pressure in the cylinders, which is muchmore considerable than most people imagine. The saving of fuel achievedby these alterations has been so marked that we understand that the stand-ard Baldwin Consolidations will in future embody these alterations. Thedifference between the initial pressure in the cylinder and the boiler pres-sure in a large number of indicator diagrams illustrated in the RailroadGazette of Jan. 2, 1885, varied from 6 lbs. to 50 lbs. The average loss ofpressure was no less than 23 lbs. The diagrams, taken with a full throttleopening, showed a loss varying from 9 lbs. to 21 lbs., and an average lossof 15 lbs. This is a loss which it would be well to endeavor to minimize,especially when it can be cheaply and easily effected by enlarging the steam-pipes and passages, using the Allen internal passage in the slide-valve, and,above all, enforcing the rule that engines in good condition must be runwith the throttle wide open, the speed being regulated solely by the reverselever.
These engines have lately been burning slack with satisfactory results.It is found that, provided the slack is not more than a few weeks old, agood fire can be maintained. The hydrocarbons, which give soft coal mostof its heating properties, are more or less volatile, and are apt to disappearwhen the slack is exposed to the weather for any length of time. The slackhas been burned by reducing the width of the spaces in and between thegrate-bars, while the effect of the blast on the fire has been increased byplacing a lining in the stack, as shown in the annexed diagram, and by theuse of a single blast nozzle. The discharge of. the exhaust from onecylinder was found apt to produce an increase of back pressure inthe exhaust-line of an indicator diagram taken from the othercylinder, unless great care was exercised in shaping the exhaust-pipe. The efficiency of the blast, of course, depends greatly on thesize of the chimney ; as the steam expands from the blast-nozzle it shouldexactly fill the chimney as with a piston, sucking the contents of the smoke-
S.21!.^
or SMOKE BOX
Fig. 306.
NORFOLK &• WESTERN RAILROAD.
Figs. 296 to 307.
;n gin accom P an y' n g illustrations represent a fine class of Consolidationn t , e ’ w hich commenced running upon the Norfolk & Western Railroad^ latter part of the year 1884.
-Xn ne ° f tllese en gi n es was exhibited at the New Orleans Internationalj n 1 Ion > i8 85, and was the heaviest locomotive and the only Consolida-n e “gine there. •
first batch of Consolidation engines for that road were built by theWin Locomotive Works from the specifications of Mr. Charles Black-
box out after it. If the chimney is so large that the steam cannot com-pletely fill it, it is obvious that the vacuum formed will be imperfect, and,consequently, part of the useful effect of the blast will be lost. The backpressure in the cylinder appears to be influenced by the size of the blast-nozzle, rather than by the size of the stack, and, therefore, in some cases itseems to be possible to increase the efficiency of the draught by diminishingthe diameter of the chimney, and, at the same time, lessen the back pressureon the piston by increasing the diameter of the blast-nozzle. In this engine,when burning slack, the single blast-nozzle was made 4% in. diameter, andthe internal diameter of the stack was reduced to 16 in. by means of a liner.The burning of slack effected a saving of $82 per engine per month. 1 his