IMPROVEMENTS IN COMPOUND STEAM ENGINES
Year: 1885

page_text: I WALTER BROCK, of the Firm of Denny and Company, of Dumbarton, in the
County of Dumbarton, North Britain, Engineer, do hereby declare the nature of
iny Invention for "IMPROVEMENTS IN COMPOUND STEAM ENGINES to be as follows,
that is to say :-
"
My said Invention has for its object the arranging or combining together of four
cylinders in pairs, tandem fashion, in connection with two cranks, for working
steam in four successive stages of expansion, in an improved manner, and so as to
admit of the pistons, covers, and valves of the cylinders nearest the crank shaft
being more easily removed for examination or repair than has hitherto been the
case in engines with tandem cylinders.
In carrying out my Invention according to one modification I arrange the two
cylinders for operating on each crank of a screw propeller, paddle wheel, or other
shaft, in the manner known as tandem -and I place the smaller cylinder of each
pair next the crank shaft with the larger cylinder close on its outer or upper end.
The four cylinders may be variously arranged in pairs; but I prefer to have the
first-stage cylinder and the second-stage cylinder together in connection with one
crank, the third-stage and fourth-stage cylinders being together in connection with
the other crank.
Thus the first-stage and third-stage cylinders will be next the crank shaft with
the second-stage and fourth-stage cylinders on the ends of the first stage and
third-stage cylinders respectively. The cylinders of each pair may be cast in one
piece, or they may be bolted together. The smaller cylinder of each pair is
separated from the larger one by a plate forming a cover to the former and the
bottom or part of the bottom of the latter; and this plate is provided with a
stuffing-box for the piston rod, the packing used being by preference metallic.
The valve casings are treated in a similar manner; and the effect of the arrange-
ment is such that the covers, pistons, and valves of the cylinders nearest the
crank shaft can be withdrawn through the outer or upper cylinders and valve
casings.
In some cases the valves may be arranged so that they can be withdrawn
through doors in their casings; and manhole doors may be fitted on the sides of

page_text: the cylinders nearest the crank shaft, and also, in some cases on the sides of the
outer or upper cylinders, to give access to their interiors for examination.
In another modification instead of placing the larger cylinder of each pair close
on the upper or outer end of the smaller cylinder, I place the two cylinders with
a small space between them. I fit the cover on the outer or upper end of the
smaller cylinder and I provide the larger cylinder with a bottom or part bottom
which is jointed on the inside and can be withdrawn through the larger cylinder.
The cover for the smaller cylinder is provided with a stuffing box for the piston
rod the packing used being by preference metallic. A tube enveloping the piston
rod extends from the stuffing box and is secured to the bottom of the larger
cylinder in a manner admitting of its moving into the larger cylinder when the
cover of the smaller cylinder is lifted. In this second modification the smaller
piston of each pair can be raised out of its cylinder sufficiently for examining and
adjusting its packing rings and springs.

page_text: Improvements in Compound Steam Engines.
I, WALTER BROCK, of the firm of Denny and Company, of Dumbarton, in the
County of Dumbarton, North Britain, 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, that is to say :-
My said Invention has for its object the arranging or combining together of four
cylinders in pairs, tanden fashion, in connection with two cranks, for working
stean in four successive stages of expansion, in an improved manner, and so as to
admit of the pistons, covers, and valves of the cylinders nearest the crank shaft,
being more easily removed for examination or repair than has hitherto been the
case in engines with tandem cylinders.
In carrying out my Invention I arrange the two cylinders for operating on each
crank of a screw-propeller, paddle-wheel, or other shaft, in the manner known as
tandem; and I place the smaller cylinder of each pair next the crank shaft with
the larger cylinder close on its outer or upper end. The four cylinders may be
variously arranged in pairs, but I prefer to have the first-stage or high-pressure
cylinder and the second-stage cylinder together in connection with one crank, the
third-stage cylinder and the fourth-stage or low-pressure cylinder being together
in connection with the other crank. Thus the first-stage and third-stage cylinders
will be next the crank shaft with the second-stage and fourth-stage cylinders on
the ends of the first-stage and third-stage cylinders respectively. The cylinders
of each pair may be cast in one piece or they may be bolted together; and they
are constructed or arranged so that the covers, pistons, and valves of the cylinders
nearest the crank shaft can be withdrawn through the outer or upper cylinders and
valve casings. In some cases the valves may be arranged so that they can be
withdrawn through doors in their casings; and manhole doors may be fitted on the
sides of the cylinders nearest the crank shaft, and also, in some cases on the sides
of the outer or upper cylinders, to give access to their interiors for examination.
In another modification instead of placing the larger cylinder of each pair close
on the upper or outer end of the smaller cylinder I place the two cylinders with a
small space between them.
And in order that my said Invention and the manner of performing the same
may be properly understood I hereunto append two sheets of explanatory drawings
to be hereinafter referred to and representing parts of compound steam engines as
made with my improvements.
Figure, 1, on sheet, 1, of the accompanying drawings is a horizontal section and
figure, 2, is a vertical section of a set of compound engines made with four cylinders,
A, B, C, D, arranged in two tandem pairs and inverted in a manner suitable for
driving the screw propeller. The high-pressure or first-stage cylinder, A, is placed
under the second-stage cylinder, B, and the third-stage cylinder, C, is placed under
the fourth-stage or low-pressure cylinder. The upper half of the section in figure, 1,
is as taken through the upper cylinders, B, D, and the lower half is as taken

page_text: through the lower cylinders, A, C. Figure, 3, on sheet, 2, is a vertical section as
at right angles to figure, 2, and as taken through the fourth-stage and third-stage
cylinders, C, D. Figure, 4, on sheet, 2, is a vertical section like figure, 3, but
showing a modification of some parts. In these drawings the same reference
letters and numerals are used to mark the same or like parts wherever they are
repeated.
In the modification shown in figures, 1, 2, and 3, the upper and larger cylinder,
B, or D, of each tandem pair is placed close down upon the lower and smaller
cylinder, A, or C; and each lower cylinder is separated from each upper on by a
plate, 5, forming a cover to the former and the bottom or part of the bottom to the
latter. This plate, 5, is provided with a stuffing box, 6, for the piston rod, 7, the
packing used being by preference metallic; and this plate, 5, which is made hollow
as it has to be of a depth corresponding to the space occupied by the stuffing box,
is made with a flange to fit a joint check formed for it in the outer annular part, 8,
of the bottom of the upper cylinder. On the top covers, 9, of the upper cylinders,
B, D, being removed, the upper pistons, intermediate plates or covers, 5, and the
lower pistons can all be removed through the upper cylinders.
The valves and valve casings are arranged in a similar way. The valves shown
in the drawings are ordinary slide valves, but other kinds of slide valves, or piston
valves may also be similarly arranged. The valves, V 1, V 2, for the first-stage and
second-stage cylinders, A, B, are arranged to be worked by one rod, 10, (made of
portions fixed together) and the valves, V 3, V 4, for the third-stage and fourth-
stage cylinders are similarly worked by one rod, 11, pistons, 12, working in
cylinders, 13, being shown as provided for sustaining the weight or part of the
weight of the valves and their rods. The valve casing, C1, of the first-stage
cylinder, A, is directly below the valve casing, C 2, of the second-stage cylinder, B,
being divided therefrom by an intermediate plate or cover, 14, having a stuffing
box for the valve rod, and arranged so as, when unbolted, to be removable upwards
along with the lower valve, V 1, through the upper casing, C2. The exhaust port
of the lower casing, C1, communicates with the upper casing C 2, by a passage or
pair of passages a part of which is shown at, 15. The exhaust port of the second
stage cylinder, B, communicates by an inclined pipe, 16, with the valve casing, C3,
of the third-stage cylinder, C; and the casing, C3, is divided from the upper
casing, C4, by an intermediate plate or cover, 17, having a stuffing box for the
valve rod and arranged so that it along with the lower valve V, 3, can be removed
upwards through the upper casing C, 4; whilst the exhaust port of the third-stage
cylinder, C, communicates with the upper casing, C4, by a passage or passages
part of which is shown at, 18, the exhaust from the fourth-stage cylinder being
led to the condenser in the ordinary way. Manhole doors, 19, are shown as
provided in the sides of the cylinders to give access to their interiors.
Any parts of the engines not shown in the drawings or herein before described
are to be understood as being constructed as in existing engines; and it is also to
be understood that my improvements are applicable with horizontal or inclined
cylinders as well as with vertical cylinders.
In the modification shown in figure, 4, which figure represents a pair of tandem
cylinders, C, D, of the proportions of the third-stage and fourth-stage cylinders of
the modification shown in figures, 1, 2, and 3, the cylinders are placed with a small
space between them; and a cover, 20, is fitted on the outer or upper end of the
smaller cylinder, C, whilst the upper and larger cylinder, D, is provided with a
bottom or part bottom, 21, which is jointed on the inside and can be withdrawn up
through the larger cylinder, D. The cover, 20, of the smaller cylinder, is provided
with a stuffing box, 22, for the piston rod, 7, the packing used being by preference
metallic. A tube, 23, enveloping the piston rod, 7, extends up from the stuffing
box, 22, and is arranged in a manner admitting of its moving into the larger
cylinder, when the cover, 20, of the smaller cylinder is lifted, the connection of
the tube with the bottom, 21, of the upper cylinder being made steam tight by a
stuffing box, 24. In this second modification the smaller piston of the pair can be

page_text: raised out of its cylinder sufficiently for examining and adjusting its packing rings
and springs, without moving the bottom, 21, of the upper cylinder.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is
1. The combination in a compound steam engine of four cylinders arranged in
pairs tandem fashion in connection with two cranks and working steam in four
successive stages of expansion, substantially as herein before described, the smaller
cylinder of each pair being nearest the crank shaft.
2. The constructing of a pair of compound, cylinders tandem fashion with the
smaller cylinder nearest the crank shaft, and with parts admitting of the piston,
cover, and valve, of the smaller cylinder being withdrawn through the larger
cylinder and valve casing substantially as and for the purposes hereinbefore
described.
EDMUND HUNT,
Applicant's Agent.