Improvements in Steam or other Motive-power Engines.
Year: 1893

page_text: Date of Application, 7th Jan., 1893
Complete Specification Left, 9th Oct., 1893-Accepted, 11th Nov., 1893
PROVISIONAL SPECIFICATION.
Improvements in Steam or other Motive-power Engines.
I GEORGE HUGHES, of 38 Chancery Lane, in the County of London, Patent
Agent (a communication to me by James Smith, of Dresden, in the County of
Yates and State of New York, U.S. America, Engineer) do hereby declare the
nature of this invention to be as follows:-
The object of the invention is to provide certain new and useful improvements in
engines, whereby the motive agent is utilized to the fullest advantage, its pressure
never falling much below exhaust-pressure after expansion has taken place.
The improvement consists principally in a device, preferably a valve, for con-
necting the two ends of a cylinder with each other at a time when the pressure of
the live motive agent on the driving side of the piston is about equal to the exhaust
or reservoir pressure on the other side of the piston, the pressure of the exhaust
being the active force to actuate the device (to open the valve) to establish com-
munication between the two ends of the cylinder, so as to permit the exhaust to
pass to the driving side of the piston to mingle with and to reinforce the live motive
agent, so that its tension is equal to the exhaust-pressure up to the end of the stroke
of the piston.
According to my invention, the cylinder contains the piston in which is formed a
longitudinal passage adapted to connect the two ends of the cylinder with each
other. At the ends of this passage, on the face of the piston, are formed valve-
seats adapted to receive valves attached to a common valve-stem, extending through
the passage. In this passage is arranged a coiled spring normally resting with its
ends on forked cross-rods, extending transversely through the passage-way.
ends of the spring are adapted to be engaged by shoulders formed on auxiliary
valve-stems, respectively, of the first-mentioned valves, respectively.
The
When no excess of pressure is on either side of the piston, these said valves are
held off their seats by the spring, which opens outward at both ends up to the cross-
rods, and by engaging the shoulders of the auxiliary valve-stems, hold the valves
off their seats. The spring is of sufficient strength to hold both valves off their
seats, as described, during the passage of vibrating currents and until compression
or live steam seats them.
Dated this 7th day of Jon 1892
HUGHES, SON & Co.,
38, Chancery Lane, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Steam or other Motive-power Engines.
I GEORGE HUGHES, of 38, Chancery Lane, in the County of London, Patent
Agent (a communication to me by James Smith, of Dresden, in the County of
Yates and State of New York, U.S. America, Engineer) do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The object of the invention is to provide certain new and useful improvements in
engines, whereby the motive agent is utilized to the fullest advantage, its pressure
never falling much below exhaust-pressure after expansion has taken place.
The invention consists in certain parts and details and combinations of the same,
as will be fully described in example hereinafter, and then pointed out in the
claim.

page_text: Reference is to be had to the accompanying drawings forming a part of this
Specification, in which similar letters of reference indicate corresponding parts in
all the figures.
Fig. 1 is a sectional side elevation of the improvement.
Fig. 2 is an indicator-diagram of an ordinary engine, and
Fig. 3 is an indicator-diagram of my improved engine.
The improvement consists principally in a device, preferably a valve or valves
favorably located, for connecting in any wise, the two ends of a cylinder with each
other at a time when the pressure of the live motive agent on the driving side of
the piston is about equal to the exhaust or reservoir pressure on the other side of
the piston, the pressure of the exhaust being the only active force to actuate the
device (to open the valve) to establish communication between the two ends of the
cylinder, so as to permit the exhaust to pass to the driving side of the piston to
mingle with and to reinforce the live motive agent, so that its tension is equal to
the exhaust-pressure up to the end of the stroke of the piston.
As shown in the accompanying illustrative drawings, the device is applied to the
cylinder of an ordinary single steam-engine; but it is evident that the improvements
can be readily adapted to all kinds and forms of engines.
As shown, for example, in Fig. 1, the cylinder A contains the piston B, in which
is formed a longitudinal passage C, adapted to connect the two ends of the cylinder A
with each other.
At the ends of this passage C, on the face of the piston B, are formed valve-seats
adapted to receive the valves D and E, attached to a common valve-stem F
extending through the passage C.
In the passage C is arranged a coiled spring G, normally resting with its ends on
the forked cross-rods G1 G2, extending transversely through the passage-way, as is
plainly shown in the drawings. The ends of the spring G are adapted to be
engaged by shoulders D' and El, formed on the auxiliary valve-stems D' and E³,
respectively, of the valves D and E, respectively. When no excess of pressure is
on either side of the piston, the valves D and E are held off their seats by the
spring G, which opens outward at both ends up to the cross-rods G' and G2, and by
engaging the shoulders D' and E¹ of the auxiliary valve-stems D and E off their
seats. The spring G is of sufficient strength to hold both valves off their seats, as
described, during the passage of vibrating currents and until compression or live
steam seats them—that is, when a preponderance of pressure is on either side of
piston, then the respective valve on that side is seated on the seat at the respective
end of the passage C, while the other valve is correspondingly moved farther off
its seat, as will be readily understood by reference to the drawings, which show the
valve in this position.
When the valves are both unseated, they then permit the remaining portion of
the exhaust agent on the exhaust side of piston to pass into the pressure side. Now
when the motive agent passes into the left end of the cylinder A to drive the piston B
in the direction of the arrow a', then the motive agent seats the valve D, and
communication between the two ends of the cylinder A is cut off.
When the slide valve has cut off the supply of the motive agent, the latter
expands until the pressure of the motive agent reaches a pressure corresponding to
the exhaust on the opposite side of the piston B and the right-hand end of the
cylinder A.
When the two pressures on the opposite sides of the piston B are about equal,
then the valve D is opened by the force of the exhaust, so that the latter can pass
through the now open passage C into the left-hand end of the cylinder A to mingle
with the motive agent contained therein. The motive agent on the driving side is
thus reinforced and prevented from falling below back or exhaust reservoir pressure
up to the end of the stroke of the piston B.
On the return stroke of the piston, the live motive agent passing into the right-
hand end of the cylinder A forces the valve E to its seat on the passage C so that
communication between the two ends of the cylinder is cut off. The motive agent

page_text: acts with supply-pressure on the piston B until the supply is finally cut off and the
motive agent expands until its pressure becomes finally equal to the pressure of the
exhaust on the left-hand side of the piston B, when the valve E is again opened by
the force of the exhaust pressing on the said valve E from the inside of the
passage C.
The exhaust now mingles with the motive agent in the right-hand end of the
cylinder A, and thus reinforces the same to prevent its pressure from falling much
below exhaust or back pressure.
By reference to Fig. 2 it will be seen that the pressure in the cylinder falls below
back-pressure before the piston is at the end of the stroke, causing the usual back-
pressure. As will be seen by my indicator-diagram shown in Fig. 3, the pressure
does not fall below back-pressure during any time of the stroke.
It will be seen from the foregoing that the device is actuated only at a certain
time that is, according to the pressures at both ends of the cylinders.
I am aware that devices have been constructed to establish a communication
between the two ends of the cylinder at the time the piston reaches a predetermined
position, so that the device is always actuated at the same point in the travel of the
piston. My device is actuated only when the live motive agent and the exhaust
are in the condition above described. Thus the device is actuated at different
times in the travel of the piston when the pressures of the motive agent or the load
vary.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
In an engine, a cylinder, a piston operating therein and provided with a passage-
way and bars near the ends of the said passage-way between the bars, and two
valves held on the ends of the said passage-way and connected with each other by a
valve-stem, the valves being adapted to be closed by compression and the live
motive agent, and are arranged to be held off their seats by the said spring at the
time the pressures on the two sides of the piston are about equal, substantially as ·
described and illustrated.
Dated this 9th dow of October 1802
HUGHES, SON & Co.,
38, Chancery Lane, London, W.C., Agents for the Applicant.