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ARTICLE XVI.
DESCRIPTION OF A STEAM ENGINE ON TIlE NEW
PRINCIPLE.
EXPLANATION OF PLATE I.
PLATE I. represents a perpendicular section of the different parts of a steam engine on the new principle explained in this work, but they are differently arranged in the construction.
a The end view of the boiler, consisting of two cylindrical tubes, the best form for holding a great power, the lesser inside of the greater. The fire is kindled in the inner one, which serves as a furnace, the water being between them. The smoke passing to the other end, is turned under the supply boiler, b, to heat the water for supplying the waste occasioned by workmg; c the supply pump, which brings water up, and forces it into the supply boiler, at every stroke of the engine.
The steam ascends the pipe, and if the throttle valve d
be lifted to let the steam into the engine, and valves e and
f be opened, the steam drives the piston g to the lower end
of the cylinder, as it appears in the plate, the steam escaping before the
piston through the valve f. As soon as the piston is down the valves
e f shut and h i open, the steam enters at h to drive
the piston up again, and escapes before the piston through the valve i.
These 4 valves are wrought by 2 wheels, k l with cams on their sides,
which strike against 4 levers, not shown
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in the plate, to which the stems of the valves are attachcd, and which open and shut them at the proper time. The motion of the piston g gives motion to the lever m n; and the rod m o, connected to the crank, puts it in motion, and the fly wheel q r keeps its motion regular; the spur wheels s t, of equal size, move the valve wheels l k; the lever m n works the supply pump c. Thus the motion is continued, and the cog wheelv of 66 cogs going into the tunnel u of 23 cogs, gives the stone w 100 revolutions per minute, when the piston strikes 35 strokes. This cog wheel may move any other work, or instead thereof a crank may move a pump or saw, as this engine may be made to strike from 10 to 100 strokes per minute, as the ease may require; and if the working cylinder be 8 inches diameter, it will drive a pair of 5 feet millstones, or other work requiring an equal power.
The steam, after it leaves the engine, escapes up the pipe x x, through the roof of the house, or into a condenser, if one be used, or through the supply boiler to heat the water.
y A safefy valve, kept down by a lever graduated like a steelyard, to weigh the power of the steam; this valve will lift and let the steam escape, when its power is too great.
If the pipe of the safety valve be turned into the flue of the furnace, then, by lifting the valve, the ashes may be blown out of the flue.
This engine is of a simple construction, easily exeeuted by ordinary mechanics: the valve seats are formed by simple plates, with holes in them and are easily cast.
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In working this engine to drive ten saws, we find that if we put her in motion as soon as she has power to drive one saw, and suffer her to move briskly, she carries off the heat from the boiler nearly as fast as it is generated, and fuel may be consumed and time spent to little purpose; but if we confine and retain the steam in the boiler, until it lifts the safety valve with a power sufficient to drive ten saws, she will start with that load, and carry it all day, and consume but little more fuel.
It takes up but little room in the building. The draught is drawn from half an inch to a foot, except the millstones, and two wheels that move them; they are a quarter of an inch to a foot.
