IMPROVEMENTS IN OBTAINING MOTIVE POWER BY MEANS OF STEAM
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by William John Hodge and John
William Greayer at the Office of the Commissioners of Patents, with
their Petition, on the 2nd February 1870.
We, WILLIAM JOHN HODGE, of No. 28, Gravel Lane, Southwark, in
the County of Surrey, and JoHN WILLIAM GREAYER, of 30, High Street,
Bow, in the County of Middlesex, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN OBTAINING MOTIVE POWER BY MEANS OF
STEAM," to be as follows:-
1
Our Invention has for its object improvements in obtaining motive
power by means of steam. For this purpose we return the uncondensed
steam from a steam engine again into the steam chamber of the boiler
by the following means:-We return the uncondensed steam into the
boiler by rotary or any other pumps or by back pressure on the piston of
the motive-power engine througli a small valve about one-quarter or
one-third the area of the steam pipe. We prefer to use a rotary engine
as a motive power to give motion to the pumps used for the purpose of
returning the uncondensed steam into the boiler. We prefer to employ
double-acting rotary engines, and use the one half of the circumference
as a motive-power engine, and the other half of the circumference as a
pump.

page_text: The rotary engine which we use, and which forms a part of our
Invention, consists in a cylinder with a groove with slightly inclined
sides passing around its circumference internally. Within the cylinder
is a concentric axis and drum with arms or pistons upon it fitting tho
groove in the cylinder. There is a partition in the groove, and the inlet
and outlet pipes are placed one on either side of this partition. If
steam or fluid under pressure is admitted to the groove between the
abutment and the arm or piston, this together with the drum and axis
will be forced round. When the arm or piston comes up to the abut-
ment it is drawn back by means of a cam groove which governs it. Two
or more arms or pistons are employed so that one may always be in
action to retain the steam or fluid whilst the other is drawn back to pass
the abutment. The engine may be made double-acting by employing
two abutments and a greater number of arms or pistons; such an engine
may be used partly as a pump as already described. We can drive the
pumps for returning the uncondensed steam into the boiler by the motive-
power engine by means of strap or wheel gearing, but this plan takes up a
certain amount of the power of the engine as when driving the ordinary air
and feed pumps. We prefer to drive the return pumps by a rotary engine
placed between the boiler and the motive-power engine and deriving its;
motion and power from the steam on its way from the boiler to the
motive-power engine. By this arrangement we retain all the power of the
said motive-power engine, which power remains to be applied to useful
work. We can use any rotary engine as a motive power to drive the
returning pumps used for returning the steam in an uncondensed-state
into the boiler. By using the before-named appliances we are enabled to
return the steam into the boiler again in an uncondensed state. Wo
prefer returning the uncondensed steam through a superheater into tho
boiler and discharging it as low in the water in the boiler as possible.
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