IMPROVEMENTS IN MARINE ENGINES
Year: 1882

page_text: LETTERS PATENT to John Finlay Rankin and Matthew Rankin both of
Greenock in the County of Renfrow North Britain Engineers for an invention
of IMPROVEMENTS IN MARINE ENGINES
PROVISIONAL SPECIFICATION left by the said John Finlay Rankin and
Matthew Rankin at the Office of the Commissioners of Patents on the
20th April 1882.
JOHN FINLAY RANKIN and MATTHEW RANKIN, both of Greenock, in the County
of Renfrew, North Britain Engineers "IMPROVEMENTS IN MARINE ENGINES'
"
This Invention relates principally to marine engines having four steam cylinders
and has for its object the arranging or combining of these cylinders and other parts
of the engines so that whilst under ordinary circumstances the four cylinders work
together as one compound engine with triple or quadruple expansion, they are
capable of being disconnected in such manner that two of the cylinders may
operate independently of the other two. The arrangements comprised in the
Invention are designed principally for advantageous application to twin screw
propellers, but are also suitable for driving paddle wheels when arranged so that
the two wheels can be disconnected.
In one modification suitable for driving twin screws, the two screw shafts are
formed each with two cranks, and the four cylinders which are inverted are placed
one above each crank. There is in this modification a single high pressure cylinder,
a single intermediate cylinder, and two low-pressure cylinders, the steam passing
equally into the two low-pressure cylinders from the intermediate cylinder, so that
it has three stages of expansion, when the two shafts are being driven uniformly
under ordinary circumstances. The high pressure cylinder and one low-pressure
cylinder act on one shaft, and the intermediate cylinder and other low-pressure
cylinder act on the other shaft. The high-pressure cylinder exhausts into a first
receiver which is in communication with the valve casing of the intermediate
cylinder, and this cylinder exhausts into two second receivers which are in com-
munication with each other and with the valves of the low-pressure cylinders,

page_text: Between the main steam pipe and the first receiver there is a pipe or passage
provided with a stop valve and a reducing valve; and between the first receiver
and the second receivers there is a pipe or passage provided either with a stop
valve to be opened or closed by hand, or as is preferred, with a loaded valve which
is automatic and requires no attention. With these arrangements, on suitably
setting the valve gear one pair of cylinders can be made to operate quite indepon-
dently of the other pair. The additional pipes or passages and valves required to
allow the disconnecting of the cylinders may be arranged in various ways to suit
different cases.
In another modification of the general arrangement the four cylinders are
proportioned for quadruple expansion the high-pressure cylinder and the lowest-
pressure cylinder being placed on one side in connection with one shaft and the
first and second intermediate cylinders being placed on the other side in connection
with the other shaft.
In other modifications each shaft may have only one crank on it, to be acted on
by two cylinders placed either one above the other, or in inclined positions; and
-in-some-cases in which triple expansion is employed there may be two high-pressure
cylinders-or two-intermediate cylinders, instead of two-low-pressure-cylinders, the_
arrangements with two low-pressure cylinders are however to be preferred.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Finlay Rankin and Matthew Rankin in the Great Soal
Patent Office on the 19th October 1882.
JOHN FINDLAY RANKIN, and MATTHEW RANKIN, both of Greenock, in the County
of Renfrew, North Britain "IMPROVEMENTS IN MARINE ENGINES."
Our said Invention relates principally to marine engines having four steam
cylinders, and has for its object the arranging or combining of these cylinders and
the other parts of the engines so that whilst under ordinary circumstances the four
cylinders work together as one compound engine with triplo or quadruplo expan-
sion, they are capable of being disconnected in such manner that two of the cylinders
may operate independently of the other two. The arrangements comprised in our
Invention are designed principally for advantageous application to twin screw
propellers, but are also suitable for driving paddle wheels when arranged so that
the two wheels can be disconnected.
And in order that our said Invention and the manner of performing the same
may be properly understood we hereunto append seven sheets of explanatory
drawings to be hereinafter referred to and representing various modifications of our
improved marine engines.
Figures 1 and 2 on sheets 1 and 2 of the accompanying drawings are an end
elevation and a horizontal section of the first modification of our four-cylinder
triple-expansion engines for driving twin screw propellers. Figuro, 3, sheet 2 and
figure, 4, sheet 3, are horizontal sections of the second and third modifications
which are also triple-expansion engines. Figure 5, sheet 3, and figure 6, sheet 4,
are a horizontal section and an end elevation of a modification designed for
quadruple expansion. In the modifications shown in Figures 1 to 6 the cylinders
are arranged in connection with four cranks; figure 7, sheet 5, is an elevation of a
modification in which the cylinders are arranged in connection with two cranks
but which is otherwise substantially the same as the first modification. Figure, 8,
sheet, G, is an elevation of a modification in which the cylinders are arranged in
connection with two cranks but which is otherwise substantially the same as the
modification shown in figures 5 and 6. Figures, 9, and 10, sheet 7, are a side
elevation and a plan of a modification of four-cylinder triple-expansion engines for
driving a pair of disconnecting paddle wheels, and figures 11 and 12, sheet 7, are a
side elevation and a plan of similar paddle engines but arranged for quadruple
expansion. In these drawings the same reference numerals are used for marking
the same or like parts wherever they are repeated. Minor details or parts of the
engines which are not shown in the drawings are to be understood to be constructed
or arranged as in existing marine engines.
In the first modification, figures 1, 2, the two screw shafts, 13, 13, are formed
cach with two cranks, and the four cylinders, 14, 15, 16, 17, which aro inverted
are placed one above each crank. There are in this modification two high-pressure
cylinders, 14, 15, one over each shaft, with one intermediate cylinder, 16, and one
low-pressure cylinder, 17, and the exhaust steam from the two high-pressure
cylinders, 14, 15, passes into spaces, 18, 19, surrounding those cylinders and con-
nected by a pipe, 20, one, 18, of those spaces being extended to form the valve
casing, 21, of the intermediate cylinder, 16, and the spaces and pipe together
forming a first receiver. The exhaust steam from the intermediate cylinder, 16,
passes into a pipe, 22, and by it into the valve casing, 23, of the low-pressure
cylinder, 17, these together constituting the second receiver. On the pipe, 22,
leading to the valve casing, 23, of the low-pressure cylinder, 17, there is a spring-
loaded valve, 24, having an outlet, 25, which communicates with the condenser, 26,

page_text: or with the atmosphere; and the low-pressure valve casing, 23, is connected by a
pipe, 27, fitted with a spring-loaded by-pass valve, 28, to the space, 19, forming
part of the first receiver. A branched pipe, 29, fitted with separato throttle
valves, 30, 31, supplies steam to the two high-pressure cylinders, 14, 15, and when
the two shafts are being worked together the steam operates through three stages
of expansion, the two bigh-pressure cylinders being equal, whilst the intermediate
cylinder, 16, acting on one shaft and the low-pressure cylinder, 17, acting on the
other shaft are proportioned so as with the pressures intended to be employed the
powers acting on the two shafts may be as nearly equal as possible. When the port
engines are stopped (by means of the reversing gear, the two throttle valves, 30, 31,
remaining open) steam acts in the starboard high-pressure cylinder 14,' exhausting
into the first receiver, 18, 21, and thence acts in the intermediate cylinder, 16, from
which the steam exhausts by the pipe, 22, and spring-loaded valve, 24, into the
condenser or atmosphere as may be arranged. If on the other hand the starboard
engines are stopped, the steam exhausting from the port high-pressure cylinder, 15,
passes by the spring-loaded by-pass valve, 28, to the valve casing, 23, of the low-
pressure cylinder, 17.
In the second modification of triple-expansion engines, figure 3, there are one
high-pressure cylinder, 14, two intermediate cylinders, 16, 16', and one low
-pressure cylinder, 17. The space, 18, round the high-pressure cylinder, 14,
communicates directly with the valvo casing, 21,-of-one-intermediate cylinder, 16,
which acts on the same shaft; and the same space 18, also communicates by a
pipe, 32, with the valve casing, 21', of the other intermediate cylinder, 16', which
acts on the same shaft as the low-pressure cylinder, 17, the space, 18, pipe, 32, and
casings, 21, 21, forming the first receiver. The second receiver is like that of the
first modification-excepting that_it_has_as part of it a space, 33, round one 16', of
the intermediate cylinders. A passage with a reducing valve, 34, is-provided-for
admitting steam of limited pressure from tho main. steam supply pipe, 35, to the
first receiver space, 18. If the port engines are stopped the steaia exhausted from
the high-pressure cylinder, 14, next works in the starboard intermediate cylinder, 16,
from which it passes through the spring-loaded valve, 24, to the condenser or
atmosphere. When the starboard engines are at rest steam entering the first
receiver through the reducing valve, 34, works the port intermediate cylinder, 16',
and afterwards the low-pressure cylinder, 17.
In the third modification of triple-expansion engines figure, 4, there are one high-
pressure cylinder, 14, one intermediate cylinder, 16, and two low-pressure cylinders
17, 171, theso last being of one size. With the port engines stopped the steam
exhausted from the high pressure cylinder, 14, passes by a pipe 32, and through a
spring-loaded valve, 36, and branch, 37, into the space, 33, on the port side forming
part of the second receiver and thence returns by the pipe, 22, to the valve
casing 23', of the starboard low-pressure cylinder, 17. With the starboard engines
stopped steam entering by a reducing valve, 34, into the first-receiver space, 18,
passes by the pipe, 32, to the valve casing, 21, of the intermediate cylinder, 16,
and afterwards works the starboard low-pressure cylinder, 17.
In the modification of quadruple expansion engines shown in figures, 5 and 6,
sheets 3 and 4, one shaft is acted on by the high-pressure cylinder, 14, and by the
first intermediate cylinder, 151, and the other shaft is acted on by the second
intermediate cylinder, 16, and by the low-pressure cylinder, 17. There are three
receivers, the first being formed by a space, 18, round the high pressure cylinder, 14,
and communicating with the valve casing of the first intermediate cylinder, 15';
the second receiver is formed partly by a pipe, 38, connecting the exhaust port of
the first intermediate cylinder, 15', with the valve casing, 21 of the second inter-
mediate cylinder, 16; and the third receiver is formed by a space, 33, round the
cylinder, 16, and in communication with the valve-casing, 23, of the low-pressure
cylinder. 17. The pipe, 38, forming the second receiver has connected to it a
branch pipe, 39, for receiving steam of limited pressure through a reducing
valve, 34, from the main steam supply pipe, 35; and there is also connected to

page_text: the pipe, 38, a spring-loaded valve, 24, and outlet, 25, communicating with the
condenser or atmosphere. When the port engines are stopped the steam works in
the high-pressure cylinder, 14, and in the first intermediate cylinder, 15¹, and then
passes to the condenser or atmosphere by the spring-loaded valve on the connecting
pipe, 38. When the starboard engines are stopped steam ontering by the reducing
valve, 34, works in the second intermediate cylinder, 16, and then in the low-
pressure cylinder, passing from the latter to the condensor in the ordinary way,
The modification of triple-expansion engines shown in figure, 7, sheet, 5, is
substantially the same as the first modification, excepting that each shaft 13, 13,
has only one crank cach crank being acted on by two cylinders placed one above
the other whilst the pipe, 20, connecting the exhaust ports of the high-pressure
cylinders, 14, 15, is made with a branch leading to the valve casing, 21, of the
intermediate cylinder, 16.
The modification of quadruple-expansion engines shown in figure, 8, sheet 6, is
substantially the same as the modification shown in figures, 5, and 6, sheets 3 and 4,
excopting that each shaft, 13, 13, has only one crank, each crank being acted on
by two cylinders placed one above the other. A pipe, 40, connects the exhaust of
the high-pressure cylinder, 14, to the valve casing of the first intermediate
cylinder, 15, and the oxhaust of the second intermediate cylinder, 16, is similarly
connected to the valve casing, 23, of the low-pressure cylinder 17. The reducing
valve, 34, for supplying the port engines with steam when the starboard engines
are stopped is shown as connected directly to the valve casing, 21, of the second
intermediate cylinder, 16, and will require to receive steam from a separate branch
supply pipe.
In the triple-expansion paddle engines shown in figures, 9, and 10, sheet, 7, tho
steam cylinders with their valve casings receivers and connecting pipes are
arranged relatively to each other as in the modification shown in figure, 7, sheet 5;
and in the quadruple expansion paddle engines shown in figures, 11, and 12, the
steam cylinders with their valve casings receivers and connecting pipes are
arranged relatively to each other as in the modification shown in figure, 8, sheet, 6.
Having thus particularly described our said Invention and tho manner of
performing the same we have to state that we do not restrict ourselves to the precise
details herein described or delineated but that what we believe to be novel and
original and claim as the Invention secured to us by and in terms of the herein-
before in part recited Letters Patent is :-
:-
1. The arranging or combining together of the parts of disconnecting engines
for driving twin scrows or disconnecting paddle wheels substantially in any of tho
modes hereinbefore described with reference to figures 1, 2, 3, 4, 7, 9, 10, of the
accompanying drawings such engines comprising four cylinders working with three
stages of expansion when not disconnected.
2. The arranging or combining together of the parts of disconnecting engines
for driving twin screws or disconnecting paddle wheels substantially in any of the
modes hereinbeforo described with reference to figures 5, 6, 8, 11, 12, of the
accompanying drawings, such engines comprising four cylinders working with four
stages of expansion when not disconnected.
In Witness whereof I the said John Findlay Rankin on behalf of myself and
the said Matthew Rankin, have hereunto set my hand and seal this
seventeenth day of October in the year of our Lord One thousand eight
hundred and eighty-two