IMPROVEMENTS IN THE MEANS AND APPA- RATUS FOR REGULATING THE SUPPLY OF STEAM TO STATIONARY, LOCOMOTIVE, AND MARINE STEAM ENGINES
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by Charles Denton Abel at the Office
of the Commissioners of Patents, with his Petition, on the 7th
February 1866.- A communication from abroad by Charles Achille
Tranchant, Civil Engineer, of Paris, in the Empire of France.
I, CHARLES DENTON ABEL, of No. 20, Southampton Buildings, Chancery
Lane, in the County of Middlesex, Patent Agent, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MEANS AND APPA-
RATUS FOR REGULATING THE SUPPLY OF STEAM TO STATIONARY, LOCOMOTIVE, AND
MARINE STEAM ENGINES," to be as follows:-
This Invention has for its object to effect a considerable saving in the
consumption of fuel in steam engines of all descriptions by a peculiar mode
of arranging and actuating the slide valves and expansion gear thereof. For
this purpose the steam cylinder is provided with two separate slide valve
boxes arranged one on top of the other, or in any other known manner; into
the upper one of which boxes the steam enters, and which communicates with
the lower valve box through one single aperture. In the upper valve box is
arranged a hollow expansion slide having two openings, through which the
steam is alternately admitted into the lower valve box as they pass over the
before-mentioned aperture in the valve box face. The end of the rod of this
expansion slide is hinged to one end of a double-ended lever, the other end of
which has the requisite rocking motion imparted to it from an excentric on
the crank shaft. The fulcrum of this lever is capable of varying its position
relative to the points of attachment of the slide valve and excentric rods,

page_text: thereby also varying the stroke of the expansion valve according to the speed
of the engine, by being attached to the slide of a pendulum governor, or to
the moving part of any other known arrangement of governing or regulating
apparatus, and by being made to work in a slot formed in the lever, which is
prevented from rising and falling with its moveable fulcrum by a curved loop
formed on its lower extremity being made to work on a fixed pin.
In applying this arrangement of expansion gear to locomotive engines the
function of the ordinary governor may be replaced by the frictional action
of one of the locomotive wheels, or the axle thereof,-upon-a lever so
arranged in connection with a spring or weight, in a similar manner to that
of the frictional brake dynamometer, that upon the decrease or increase of
the speed of the engine, and consequently of the friction of the axle or wheel
against the lever, the resulting motion-of the-lever is imparted to the before-
mentioned moveable fulcrum of the rocking lever to the expansion gear.
Also, in place of employing the ordinary pendulum governor for the purposes
of this Invention, more particularly in marine steam engines, annular steel
springs may be substituted for the pendulum balls, which springs in being
made to revolve upon an axis passing through their diameter are caused by
the centrifugal force to assume a more or less elliptical shape in a manner
well known, and thereby effect the motion of the before-mentioned moveable
fulcrum.
It is an essential part of this Invention for effecting the economy in fuel
before mentioned that no steam should be admitted to the steam cylinders
when the cranks are at the dead points. For this purpose the excentrics to
the slide valves are fixed in such a position upon their shaft that the steam
is only admitted behind or in front of the piston after it has passed through
from one-sixth to one-quarter of its forward or backward stroke, in place
of causing the steam to enter before the piston arrives at end stroke, as is
usually done. The piston in being made to move through part of its stroke
as described, by the momentum of the fly wheel produces a vacuum behind
it, into which the steam subsequently rushes with a proportionately increased
speed. By this arrangement and by the before-described mode of regulating
the motion of the expansion slide according to the speed of the engine, a con-
siderable economy in the employment of the steam, and consequently in the
requisite fuel, will be effected.