BOILERS FOR STATIONARY ENGINES.
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changing the flow or current of the steam. To a vertical chambera right-angled pipe is suspended, passing down into the chambera little below the exit pipe; the steam flowing through the pipefrom the boiler impinges against the elbow, causing the moisturecontained in the steam to trickle down the pipe, thus the water iscollected at the bottom of the receiver, and is drawn off at pleasurewith a tap; this plan is very simple, and it can be made self-actingby means of a float and valve. We consider these Separators fordrying the steam, or rather separating the moisture contained in thesteam, should be fitted to all steam-pipes.
Taking Low-pressure Steam from a High-pressure Boiler. —Some-times it is desirable to reduce the pressure of the steam, so as to work alow-pressure engine from a high-pressure boiler. There are a varietyof plans for doing so; we have an equilibrium valve, actuated by thepressure of the steam acting on a piston open to the atmosphere,and regulated by a lever and spring-balance, similar to the safety-valve on the locomotive engine boiler. The valve is formed of fiverings cast together, with four vertical arms, or ribs, having a bossfor securing the valve-spindle; this annu-lar tube moves in a corresponding seat,cast together, with vertical pieces betweenthe openings; there is an annular passageall round the seat, with a branch pipecommunicating with the steam-boiler. Onthe lower part of the valve-chest a branchpipe is cast in communication with thecylinder of the valve-casing of the engine,and on the top of the ehest a short cylin-der and piston are arranged, the pistonbeing connected to the valve by a screwedrod and nuts. The combined circumfer-ential openings in the valve are equal in area to that of the pipefrom the boiler, and the pipe for the engine must be of sufficientarea according to the usual rules for steam-pipes. By this contriv-ance the steam can be regulated to the greatest nicety. The actionis as follows:—After being properly set with the nuts on the valve-spindle, and the thumb-screw on the balance at the end of the lever,should there be an accumulation of steam in the ehest, after passingthe valve, the steam acts on the piston in connection with the valve,and by its pressure lifts it partially, shutting the apertures until the