Compound Steam Engines.
Year: 1892

page_text: Date of Application, 21st June, 1892-Accepted, 8th Oct., 1892
COMPLETE SPECIFICATION.
Compound Steam Engines.
I, BENJAMIN WARREN BURNET, Gentleman, of 120 Liberty Street New
York in the County and State of New York, United States of America, 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:-
This invention relates to that class of steam engine in which exhaust steam from
the cylinder is conducted to a second cylinder for the purpose of increasing the
efficiency of steam power.
The exact nature of the invention is best set forth by reference to the accom-
panying drawings.
On these,
Fig. 1 is a longitudinal vertical section of the cylinders, plunger and bedplate;
Fig. 2 a plan of the bed plate of the cylinders and steam chest with these
removed, shewing the ports contained therein;
Fig. 3 a perspective view of the larger cylinder, showing the ports in the bottom
side thereof;
Fig. 4 is a diagram of the position of the valve and steam passages in the phase
where the steam passes from the small to the large cylinder, and of a modification
of the arrangement of passages shewn by Figs. I and 2;
Fig. 5 is an outside elevation of the part of the engine embodying my
improvements.
On the drawings a is the cylinder which takes the live steam and 6 that which
takes the low pressure steam exhausted from a, hereinafter called exhaust steam.
The cross sectional inside area of the exhaust steam cylinder b is twice that of the
live steam cylinder a. Their longitudinal axes coincide and they are at a suitable
distance from each other. A plunger or piston is provided for each and these are
rigidly connected to each other or cast in one piece so as to form a double plunger;
they are cast hollow, the ends being closed by plates c d bolted to the ends. The
smaller plunger for cylinder a is lettered e and the larger f, their appearance being
that of two cylinders of different diameters joined end to end. The lengths of the
cylinders a and b are equal to each other. At opposite ends of the cylinder a are
ports g and h, and at opposite ends of the cylinders are ports i j. These ports lead
from the respective cylinders to the steam chest. The two ports g h lead into a
common port k in the bedplate o conducting through the passage k¹ to the port k²
in the valve face n'. Similarly the ports ij lead into a common port in the bed
plate conducting through passage to port 2 in the valve face. In order to follow
the path of the steam during operation, the slide valve, marked n, is shewn on
Fig. 4 on an enlarged scale. The bed plate o with ports 12 k2 and p is shewn in
section, the port p being connected to the exhaust pipe in the usual way.
When the valve is at the extreme left of its traverse, the port is uncovered by
the edge n² of the valve and steam enters this port and through k¹k and the right
end of cylinder a, it being understood that in the diagram Figure 4 all space above
the valve n and bedplate o may be considered as the steam space or steam chest m.
The steam drives the plunger e to the left end of cylinder a, and at the same time
the excentric moves the valve to the position shown on Figure 4, so that as soon as
the plunger ƒ has arrived at the left end of the cylinder b, the exhaust steam passes
from cylinder a through the ports k k² and the passage n³ in the valve to the port *
and thence through, and i into the cylinder b. The pressure of the exhaust
steam from the cylinder a is exerted upon the plunger f (having twice the area of
that of the plunger e) and causes the compound plunger to be driven back to the
D
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page_text: starting position. In a manner similar to that of other engines, the valve so moves
next as to allow the steam from the cylinder b, to pass into the exhaust p, and
thence into the atmosphere, or into a condenser, as the case may be.
This
operation is repeated continually, whereby power is obtained for useful work.
When the plunger e, has arrived at the left end of the cylinder a, the exhaust
steam should be allowed at the very first to escape with great freedom, which for
an instant it can do through the port y communicating with ports k, l, in the then
position of the valve. In practice however this port is preferably replaced by a
pipe connecting the right end of the cylinder a with the left end of cylinder b,
as shewn in the lower part of diagram Figure 4 and on Figure 5, through which
pipe steam can pass for an instant from the said cylinder a, to the cylinder b, the
communication being then closed by the plunger e; subsequently, during the
passage of the plunger e, to the right end of the cylinder a, the steam can exhaust
itself through the pipes or ports k, k², n³, 12, 1, and i, into the cylinder b.
The function of the pipe 9' connected to q may be explained thus ;-Suppose
that the engine stops at such a phase of the piston that the plunger f, is at the
extreme left of the cylinder b; then there would be difficulty in starting the engine
again, but in view of the pipe q' which has a valve q", steam may be allowed to
enter and force the piston plunger, f to the right and thereby start the engine after
which the operation becomes automatic.
The connecting rod, r, is pivotted to the plunger f, by means of a bolts, passing
through the same. In order that there may be no rotation of the plunger, there is
provided a guide t and a slide u for it to glide along. The slide consists of two
angle irons or blocks which are attached to the plate by means of bolts v, or formed
on the same.
Those parts of the engine not herein particularly described are omitted from
description because the same are not part of the invention but common to most
other steam engines.
The plungers are surrounded by packing w. If the steam leaks, the packing can
be tightened, by means of the plates, and bolts y. In an ordinary steam engine
with pistons, it cannot be told if the steam leaks from one end to the other of the
cylinder. If such leakage does take place there is much detrimental back pressure.
In this present construction, no such hindrance can occur.
In the view Fig. 5. the pipe Q shown on top carries part of the exhaust into the
large cylinder and introduces it in an opposite direction to that entering through
port so that the two streams of steam collide. When two streams come in
opposite directions thus, the efficiency of the engine is increased. The reason is
probably that the motion is converted into heat which greatly expands the steam.
This new application of this new principle in this steam engine is applicable to any
steam engine by feeding the steam through two feed pipes so that the two streams
meet at an angle.
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 :-
1. A compound steam engine having a construction substantially as set forth
herein.
2. In a steam engine, the arrangement of two admission steam ports or inlets so
located opposite each other that the streams of steam come into collision, as and for
the purpose described.
3. A steam engine consisting of the combination of two cylinders whose extended
axes coincide, and relatively the one double the cross section of the other, and
closed at those ends farthest from each other by suitable covers bolted thereto,
plungers fitting in the remaining ends and rigidly connected together, a steam
chest having ports leading to the further ends of the said cylinders, a pipe
connecting the port going to the larger cylinder with that end of the smaller
cylinder which is nearest the larger cylinder, a pipe q' connecting with that port

page_text: which leads to the larger cylinder, an exhaust pipe leading from the steam chest,
and a valve for controlling the steam and for causing it to exhaust from the
smaller to the larger cylinder, and from the latter to the atmosphere, the said
valve being connected to an eccentric rod.
4. In a steam engine, the combination of a larger and smaller cylinder whose
axes coincide, plungers movable therein and connected together and of such length
in totum, that it extends approximately from centre to centre of the said cylinders,
means for exhausting the steam from the smaller cylinder to the larger, and a
supplementary pipe q, connecting that end of the smaller cylinder which is nearest
the other cylinder to that end of the larger cylinder which is farthest from the
first cylinder.
5. In a steam engine, the combination of two cylinders whose extended axes
coincide, concentric cylinders fitting movably therein, hollow and closed at one
end of each, the remaining ends being connected together, and corresponding pairs
of said cylinders being of such diameters that the cross-sectional areas are as
one to two, a guide t, projecting downward from the larger inner cylinder, and
located between guides u, running parallel to and between the said first cylinders,
and packing boxes surrounding the said inner cylinders at ends of the outer or
first named cylinders.
Dated the 20th der of Lune 1800
R. J. URQUHART,
57, Barton Arcade, Manchester, 5, Clayton Square, Liverpool,
Consulting Engineer and Patent Agent.