IMPROVEMENTS IN COMPOUND STEAM ENGINES to be as follows that
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
my said 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
or six cylinders, in pairs, tandem fashion, in connection with two or three cranks, for
working steam in four or six successive stages of expansion, in an improved manner,
and so as to admit of access for examination, adjustment, or repair of internal parts,
being obtained with less labor and inconvenience than has hitherto been the case
with tandem cylinders.
In carrying out my Invention I arrange the cylinders so that one of each pair
connected to the same crank receives its steam from the other; and I place either
the larger or smaller cylinder of each pair nearest the crank shaft. I apply a valve
or valves at the side of the large cylinder, for distributing the steam to both the
large and small cylinders of each pair, so that the small cylinder of each pair is
quite independent of valves and valve gear, and can be detached from the large
cylinder with very little trouble. A single slide valve may be used for the two
cylinders of a pair such valve and the port face it works on and the cylinder
passages being arranged in a well known way, so as to lead the steam first into the
small cylinder and thence into the large cylinder. The passages for the small
cylinder will be formed partly in the side of the large cylinder and partly in the
side of the small cylinder, and partly in the cover or bottom of the large cylinder.
When the small cylinder is placed on the outer end of the large cylinder, the
small cylinder may be cast in the same piece with the cover of the large cylinder;
or it may be cast in a separate piece and be bolted to the cover of the large
cylinder; or the cover of the large cylinder may be annular the small cylinder
being made with a bottom or end fitting into the annular cover. The piston rod
passes through a stuffing box in the cover of the large cylinder or bottom of the
small cylinder, the packing used being by preference metallic. With these arrange-
ments the small cylinder can be very easily detached and removed endways to give
access to the interior of the large cylinder; or it can be readily removed to one
side should it be necessary to remove the large piston.

page_text: When the small cylinder of each pair is placed nearest the crank shaft it is bolted
to the end of the large cylinder. This end or bottom has a central circular opening
large enough to allow of the small piston passing through it when required and this
opening is closed by a cover or bottom jointed from the inside of the large cylinder
so that it can be removed through it. This bottom or cover has a stuffing box for
the piston rod packed by preference with metallic packing. When access is required
to the interior of the small cylinder that cylinder is simply detached from the
bottom of the large cylinder and moved along the piston rod as far as required or
as the crosshead or slide block on that rod will allow.
My improved arrangements may be conveniently and economically adapted for
compounding existing engines.
EDMUND HUNT,
Applicant's Agent.
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 or more cylinders, in pairs, tandem fashion, in connection with two or more
cranks, for working steam in four or more successive stages of expansion, in an
improved manner, and so as to admit of access for examination, adjustment, or
repair of internal parts, being obtained with less labor and inconvenience than has
hitherto been the case with tandem cylinders. My improvements are also appli-
cable to a single pair of cylinders arranged tandem fashion, in a set of engines,
having one or more other cylinders arranged differently.
In carrying out my Invention I arrange the cylinder so that one of each tandem
pair connected to the same crank receives its steam from the other; and I place
either the larger or the smaller cylinder of each pair nearest the crank shaft.
I apply a valve or valves at the side of the large cylinder for distributing the
steam to both the large and the small cylinders of each pair; so that the small
cylinder of each pair is quite independent of valves and valve gear, and can be
detached from the large cylinder with very little trouble.
When the small cylinder is placed on the outer end of the large cylinder, the
small cylinder may be cast in the same piece with the cover of the large cylinder;
or it may be cast in a separate piece and be bolted to the cover of the large
cylinder; or the cover of the large cylinder may be annular the small cylinder

page_text: being made with a bottom or end fitting into the annular cover. The piston rod
passes through a stuffing box in the cover of the large cylinder or bottom of the
small cylinder, the packing used being by preference metallic. With these
arrangements the small cylinder can be very easily detached and removed to
give access to the interior of the large cylinder; or it can be readily removed to
one side should it be necessary to remove the large piston.
When the small cylinder of each pair is placed nearest the crank shaft it is
bolted to the end of the large cylinder. This end or bottom has a central circular
opening large enough to allow of the small piston passing through it when
required; and this opening is closed by a cover or bottom jointed from the inside
of the large cylinder, so that it can be removed through it. This bottom or cover
has a stuffing box for the piston rod packed by preference with metallic packing.
When access is required to the interior of the small cylinder that cylinder is simply
detached from the bottom of the large cylinder and moved along the piston rod as
far as required or as the crosshead or slide block on that rod will allow.
My improved arrangements may be conveniently and economically adapted for
compounding existing engines.
And in order that my said Invention and the manner of performing the same
may be properly understood I hereunto append eleven sheets of explanatory
drawings to be hereinafter referred to and representing various examples of the
application of my improvements. In these drawings the same reference letters
and numerals are used to mark the same or like parts wherever they are repeated.
Figures, 1, and 2, on sheet, 1, of the drawings are horizontal and vertical sections
of the cylinders and some other parts of a set of quadruple-expansion engines suitable
for driving the screw propeller. The cylinders are arranged in two pairs, C 1,
C2, and, C3, C4, the two cylinders of each pair being tandem with the smaller
cylinder uppermost or furthest from the crank shaft. In figure, 1, the upper half
of the section is as taken through the larger cylinders, C2, C4, the lower half
being as taken through the smaller cylinders, C1, C3. The two pistons, P1, P2,
are fixed on one rod, R, connected to one crank; and the other two pistons, P3, P4,
are fixed on another rod, R, connected to another crank. Each piston rod, R,
passes through a stuffing box, G, in the cover, D 2, or, D 4, of the larger cylinder,
the packing used being by preference met llic. The two larger cylinders, C2, C4,
are bolted together, and the valves are placed as is usual in the ordinary type of
two-cylinder compound engines; the difference being that the first-stage and
second-stage cylinders, C1, C2, are substituted for the ordinary high-pressure
cylinder, whilst the third-stage and fourth-stage cylinders, C3, C4, are substituted
for the ordinary low-pressure cylinders. It will be convenient when referring to
each tandem pair to term one pair, C1, C2, the high-pressure cylinders, and the
other tandem pair, C3, C4, the low-pressure cylinders.
The high-pressure cylinders, C1, C2, have the steam distributed to both of them
by a combination piston valve, V 1, V 2, placed in a casing, A, at the front side of
the larger cylinder, C2; and the low-pressure cylinders, C3, C4, have the steam
distributed to both of them by a flat combination slide valve, V 3, V 4, working in
the casing, B, between the two larger cylinders, C2, C 4. The smaller cylinders,
C1, C3, are cast on the covers, D2, D 4, of the larger cylinders; the connection
between the cylinders may however be arranged otherwise as shown for example
in figures, 4, and 17. When the sizes of the cylinders are suitable a manhole may
be formed in the cover of the larger one, as indicated at M, figure, 2, for giving
access to the interior. In figure, 2, and also in other figures in which piston, valves
are shown, the spaces of the packing rings of the piston parts of the valve are left
blank for the sake of clearness; any suitable arrangement of packing may however
be used. The high-pressure steam enters by a pipe at, S, (left-hand side of
figure, 2,) into an annular space from which it has access into the space between
the two pistons of the upper valve, V 1. The upper ports controlled by this
valve, V 1, lead to the bottom of the upper cylinder, C1, and the lower ports to
the top of that cylinder; and the exhaust from the upper cylinder takes place into

page_text: the casing, A, that from the upper port passing through the hollow centre of the
valve, V 1. The lower valve, V2, controls the ports of the lower cylinder, C2, in
the ordinary way, the exhaust port and passage, E 2, communicating with the space
between the valve pistons, and also with the valve casing, B, of the low-pressure
cylinders, C3, C4, this casing extending partly round the second-stage cylinder, C2,
and acting as a receiver, as usual in compound engines of the ordinary type.
The construction and operation of the slide valve, V 3, V 4, will be understood
from the drawings, the communication with the bottom of the upper cylinder, C3,
being by two passages indicated by dotted lines and passing to the port face at the
sides of the other passage and port communicating with the top of the upper
cylinder. The weight or part of the weight of the slide valve, V 3, V 4, is sustained
by a piston in a cylinder, F, at the top of the casing, whilst in the case of the
piston valve, V1, V2, the sustaining power is obtained by making the top piston,
pressed upwards by the high-pressure steam, of larger effective area than the next
lower piston on which the steam presses downwards.
L
Figures, 3, and 4, on sheet, 2, and 5, and 6, on sheet, 3, are horizontal and
vertical sections (with a part shown in plan) of parts of engines like those
shown in figures, 1, and 2, except as regards the valves for the low-pressure
cylinders, C3, C4. The upper part of figure, 3, is a plan with the smaller
cylinders, C1, C3, and also the valves and casings for distributing steam to the
third-stage cylinder, C 3, removed, so as to admit of the lower pistons, P 2, P 4, and
the lower valve, V 4, being withdrawn. The lower part of figure, 3, and figure 4,
are horizontal and vertical sections through the cylinders and the valve, V 4.
The left-hand part of figure, 5, is a horizontal section through the upper
cylinders, C1, C3, and one of the valve casings. The right-hand part of the same
figure shows a similar section, but as taken above the casing of the valve, V.3, so
that that casing is shown in plan. Figure, 6, is a transverse vertical section
through the casing, B 2, showing in elevation the valve, V 4, and in section the
valves, V 3, and their casings.
+
.
In this modification an ordinary double-ported slide, V 4, is applied to the fourth-
stage cylinder, C4, whilst two piston valves, V 3, are used for the third-stage
cylinder, C3, these piston valves being worked by rods connecting them to the
slide valve, V 4. The piston valves, V 3, work in casings formed in one piece with
what may be called the cover of the receiver casing, B2, and are in communication
with it directly and through the hollow centres of the valves, V 3. This cover
with the casings and the valves, V 3, can be removed to allow of withdrawing the
lower valve, V 4. Although the casings with the valves, V 3, are above the lower
cylinder, C4, the upper cylinder, C3, is quite separate from them, the passages for
the upper cylinder being formed partly in the sides of that cylinder, partly in the
cover, D 4, between the upper and lower cylinders and partly in the valve casings.
The exhaust passage, E 2, from the second-stage cylinder, C2, communicates by
passages cast partly round that cylinder, with the space between the pistons of the
valve, V 3, the steam after working in the cylinder, C 3, passing into the receiver
casing, B 2.
For distributing steam to the low-pressure cylinders, C3, C4, instead of the
arrangements shown in figures, 1, and 2, sheet, 1, and those shown in figures, 3,
to 6, sheets, 2, and 3, double piston valves may be used as shown in figures, 7, 8,
and 9, on sheet, 4. And, in cases where more or less distance between the
cylinders, C2, C4, is unimportant a single combination piston valve similar
to V 1, V 2, figure, 2, sheet, 1, may be used for distributing the steam to the low-
pressure cylinders, C3, C4.
In the modification shown in figures, 7, 8, and 9, sheet, 4, the cylinders are
combined like those shown in figures, 1, to 6, but with the smaller cylinders, C1, C 3,
nearest the crank shaft. Figure, 7, is a horizontal half section and figures, 8,
and, 9, are transverse vertical and longitudinal vertical sections.
Figures, 10, and 11, on sheet 5, are a plan and a side elevation of parts of
engines comprising two tandem pairs of cylinders, with the larger cylindera. Ċ 2. C 4.

page_text: nearest to the crank shaft, and with valve casings, A, B, placed angularly at the
back of the engines. These valve casings are shown as adapted for valves all of
the piston class, and as quite separate from the smaller cylinders, 01, 03.
On sheets, 6, 7, and 8, are shown parts of engines comprising six cylinders
arranged in connection with three cranks and working with four stages of
expansion, figure, 12, being a horizontal section, as taken partly through a low-
pressure cylinder, C4, partly through the second-stage cylinder, C2, partly through
the first-stage cylinder, C 1, and partly through a third-stage cylinder, C3, figure, 13,
a side elevation, figure, 14, a vertical section of the first-stage and second-stage
cylinders, C1, C2, with their valves, and figure, 15, a vertical section of either
tandem pair of low-pressure cylinders, C3, C4, with their valves, which in this
modification are shown to consist of a combination of an ordinary flat valve, V 4,
and a piston valve, V 3. The pistons of the upper valve, V 3, are in this case solid,
and the exhaust steam from the bottom of the upper cylinder, C3, passes into the
casing, B 2, by a passage, E 3, leading down thereto from the top of the casing in
which the valve, V 3, works. The first-stage and second-stage cylinders, C1, C2,
act on the middle crank, and the third and fourth stages of expansion are divided
between two pairs of cylinders which act on the two outer cranks. This arrange-
ment is intended to be adopted in the case of engines which are so large as to make
it desirable to employ two third-stage and two fourth-stage cylinders instead of a
single large cylinder for each of those stages; and it may also be used with
advantage in the cases of engines intended to be run at great speed, a better
balancing of the working parts being obtainable with the three cranks.
Figures, 16, and 17, on sheet, 9, are a plan and a vertical section of a modifica-
tion of my improved engines with four cylinders in two tandem pairs in inclined
position, and adapted for driving paddle wheels.
Figure, 18, on sheet, 10, is a horizontal section, and figure, 19, on sheet, 11, is a
corresponding side elevation of parts of engines comprising six cylinders arranged
for acting on three cranks and for working the steam through six stages of
expansion. The first-stage and second-stage cylinders, C1, C2, are arranged
tandem fashion to act on the middle crank; the third-stage and fourth-stage
cylinders, C3, C4, are arranged tandem fashion to act on one outer crank, and the
fifth-stage and sixth-stage cylinders, C5, C6, are similarly arranged to act on the
other outer crank; whilst the smaller cylinder of each tandem pair is placed furthest
from the crank shaft. The various valves are arranged in relation to the several
cylinders in the same manner as in the other modifications hereinbefore described.
In six-cylinder engines similar to those shown in figures, 18, 19, or those shown
in figures, 12, to 15, the several tandem pairs of cylinders may be respectively
arranged in connection with the three cranks in any other way than as shown that
may be considered more convenient in any particular case.
Instead of placing the several smaller cylinders of the tandem pairs close to the
larger cylinders as shown in the accompanying drawings it may be convenient in
some cases to arrange the cylinders of each tandem pair with a space between
them, so as to allow of access to the stuffing boxes, G, from the outside, and also to
allow of a manhole being fitted for giving access to the lower cylinders, in cases
where the proportions of the cylinders are such as not to admit of this being
conveniently done otherwise. In such cases I prefer to use parts for packing and
enclosing the piston rod between the two cylinders of the kind described in my
patent Specification N° 13192 of 1885.
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. In compound steam engines, the combining of any two consecutive cylinders
as a tandem pair to act on one crank, the smaller cylinder being connected to the
larger one of each pair, so that it can be detached without interfering with the

page_text: valve casing; and the valve or valves of the smaller cylinder being in a casing
attached to the larger cylinder all substantially as hereinbefore described.
2. The combining of two tandem pairs of cylinders in connection with two
cranks, or three tandem pairs of cylinders in connection with three cranks to work
the steam through four successive stages of expansion, the steam being distributed
to each tandem pair of cylinders either by a single valve or by two valves or pairs
of valves any of the said valves being piston valves or slide valves arranged to
work in casings attached to the larger cylinders substantially as hereinbefore
described.
3. The combining of three tandem pairs of cylinders in connection with three
cranks to work the steam through six stages of expansion, the valves and their
casings being arranged substantially as herein before described.
4. The combining of piston valves and flat slide valves and their casings
substantially in the manner hereinbefore described and as shown in figures, 3, 4, 5,
6, 12, 15, and 18, of the accompanying drawings.