IMPROVEMENTS IN COMPOUND MARINE STEAM ENGINES
Year: 1881

page_text: LETTERS PATENT to Alexander Carnegie Kirk, of the Firm of Robert Napier
and Sons, of Glasgow, in the County of Lanark, North Britain, for an
Invention of "IMPROVEMENTS IN COMPOUND MARINE STEAM ENGINES."
PROVISIONAL SPECIFICATION left by the said Alexander Carnegie Kirk
at the Office of the Commissioners of Patents on the 10th February 1881.
ALEXANDER CARNEGIE KIRK,, of the Firm of Robert Napier and Sons, of
Glasgow, in the County of Lanark, North Britain. "IMPROVEMENTS IN COMPOUND
MARINE STEAM ENGINES."
This Invention has for its object to improve the general construction or the
mode of arranging or combining together the steam cylinders and other parts of
marine steam engines working on the well known compound system, and the
improvements are more especially designed for advantageous application in cases
in which comparatively high pressures are used and large powers are developed
for driving the screw propeller.
In carrying out the Invention the engines are arranged for expanding the steam
three times, or in other words, for working it through three stages, there being
two cylinders for the third or final stage, so that such cylinders may be of com-
paratively moderate size. The improved engines are of the inverted-cylinder class,
and in one modification the cylinders are placed in the vertical plane of the crank
shaft with the intermediate or second-stage cylinder between the two low-pressure
or third-stage cylinders. The high-pressure or first-stage cylinder is placed above
the intermediate cylinder, the pistons of the high-pressure and intermediate
cylinders being on the same rod, which passes through one or two stuffing boxes
between the cylinders. The valve arrangements may be varied, but as it is
considered desirable to have the parts of large engines as direct in action, as simple,
and as accessible as possible, preference is given to an arrangement in which
eccentrics on the crank shaft operate through the usual link-motion, or equivalent
valve gear, on valves arranged between one of the low-pressure cylinders and the
intermediate and high-pressure cylinders. Piston valves are by preference used
..מ
072

page_text: for the high-pressure and intermediate cylinders, those admitting steam to the
high-pressure cylinder occupying a middle position with valves for the intermediate
cylinder at each side. The valves for the low-pressure cylinders may be slide
valves placed by preference transversely at the outer sides of the cylinders.
In a scond modification two intermediate cylinders are arranged one above each
low-pressure cylinder, a single high-pressure cylinder occupying the middle space;
and in a third modification four cylinders are arranged in the same line over the
crank shaft, the high-pressure cylinder being at one end, the intermediate cylinder
second, and the two low-pressure cylinders third and fourth; or the high-pressure
cylinder may be placed over the intermediate cylinder. In all the modifications
the cranks are disposed relatively to each other in a manner to secure convenient
starting, and to render the strains as nearly uniform as is practicable in the
circumstances.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Carnegie Kirk in the Great Seal Patent Office on the
9th August 1881.
ALEXANDER CARNEGIE KIRK, of the Firm of Robert Napier and Sons, of
Glasgow, in the County of Lanark, North Britain. "IMPROVEMENTS IN COMPOUND
MARINE STEAM ENGINES."
My said Invention has for its object to improve the general construction or the
mode of arranging or combining together the steam cylinders and other parts of
marine steam engines working on the well known compound system; and my
improvements are more especially designed for advantageous application in cases
in which comparatively high pressures are used, and large powers are developed
for driving the screw propeller.
In carrying out my Invention the engines are arranged for expanding the steam
three times, or in other words, for working it through three stages, there being two
cylinders for the third or final stage, so that such cylinders may be of comparatively
moderate size. In one modification my improved engines are of the inverted-
cylinder class, the cylinders being placed in the vertical plane of the crank shaft,
with the intermediate or second-stage cylinder between the two low-pressure or
third-stage cylinders. The high-pressure or first-stage cylinder is placed above the
intermediate cylinder, the pistons of the high-pressure and intermediate cylinders
being on the same rod, which passes through one or two stuffing boxes between
the cylinders. The valve arrangements may be varied, but as I consider it
desirable to have the parts of large engines as direct in action, as simple, and as
accessible as possible, I give preference to an arrangement in which eccentrics on
the crank shaft operate through the usual link-motion, or equivalent valve gear,
on valves arranged between one of the low-pressure cylinders and the intermediate

page_text: and high-pressure cylinders. Piston valves are by preference used for the high-
pressure and intermediate cylinders, those admitting steam to the high-pressure
cylinder occupying a middle position, with valves for the intermediate cylinder at
each side. The valves for the low-pressure cylinders may be slide valves placed
by preference at the outer sides of the cylinders, or in other words, at the fore and
aft ends of the set of engines.
In a second modification two intermediate cylinders are arranged one above each
low-pressure cylinder, a single high-pressure cylinder occupying the middle space,
and in a third modification four cylinders are arranged in the same line over the
crank shaft, the high-pressure cylinder being at one end, the intermediate cylinder
second, and the two low-pressure cylinders third and fourth; or the high-pressure
cylinder may be placed over the intermediate cylinder.
My improved modes of arranging and combining four or five steam cylinders to
operate with three stages of expansion may be used when the cylinders are placed
horizontally, and in this case the framing, pumps, valves, and gear are modified in
relation to the cylinders in the manner usual with horizontal engines.
In all the modifications the cranks are disposed relatively to each other in a
manner to secure convenient starting and to render the strains as nearly uniform as
is practicable in the circumstances.
And in order that my said Invention and the manner of performing the same
may be properly understood, I hereunto append three Sheets of explanatory
Drawings, to be hereinafter referred to, and representing two examples of marine
engines as constructed with my improvements.
Figures 1 and 2 on Sheet 1 of the accompanying Drawings are side and end
elevations, and Figure 3 is an enlarged vertical section, whilst Figure 4 on Sheet 2
is a plan, and Figure 5 an enlarged horizontal section, all of one modification of the
engines. Figure 6 on Sheet 2 is a plan of another modification, and Figures 7
and 8 on Sheet 3 are corresponding side and end elevations. In the Drawings the
same reference numerals are used to mark the same or like parts wherever they are
repeated. The general features only of the arrangements are shown, and it is to be
understood that any parts or details which are not delineated or described are to
be constructed or fitted as in existing engines or in an analogous manner.
In the modification shown in Figures 1 to 5 the first-stage or high-pressure
cylinder 11 is placed above the second-stage or intermediate cylinder 12, and these
two cylinders are placed in the middle space lengthways of the set of engines
between two third-stage or low-pressure cylinders 13, 13. The pistons of the high-
pressure and intermediate cylinders 11, 12, are fixed on the same rod 14, and the
arrangement of the stuffing boxes 15 between the cylinders is shown in the enlarged
section Figure 3, whilst the arrangements of the valve casings and passages of the
same two cylinders 11, 12, will be easily understood from Figures 3 and 5. Two
pairs of piston valves work in the spaces 16 at the sides of the valve casing of the
intermediate cylinder 12, the steam having access to these valves from the valve
casing of the high-pressure cylinder 11 above through a middle passage 17, up
through which passes the rod 18 for working the piston valve or valves of the high-
pressure cylinder 11. The steam exhausts in each case through the trunks of the
piston valves, the steam from the intermediate cylinder 12 passing by the pipes 19
and branch pipes 20 to the valve casings 21 of the two low-pressure cylinders 13.
The eccentrics 22 for working the valves of the middle cylinders 11, 12, act through
a link-motion 23 on vertical rods 24 guided to work vertically, and a crosshead 25
fixed on these rods 24 has the several valve rods fixed to it. The valves of the low-
pressure cylinders 13 are worked in a similar direct manner by eccentrics 26. The
condenser 27 is placed at one side of the engines, and the air and other
pumps are worked by levers connected to the piston-rod crossheads in a usual
manner.
What is herein before described as the second modification differs from that shown
in Figures 1 to 5 in having two intermediate or second-stage cylinders placed above
the third-stage or low pressure cylinders 13, whilst a single high-pressure cylinder

page_text: is placed in the position occupied by the intermediate cylinder 12 in the first
modification.
Figures 6, 7, and 8 represent the third modification, in which four cylinders are
arranged in line all at the same level, the high-pressure or first-stage cylinder 11
being at one end of the set of engines, an intermediate or second-stage cylinder 12
next, and the two-pressure or third-stage cylinders 13, 13, third and fourth. In
this modification the valve casings are all shown at one side of the engines, and the
eccentrics for working them act directly through link motions on levers indicated
by dotted lines at 28 in Figure 8.
Having thus particularly described my said Invention, and the manner of
performing the same, I have to state that I do not restrict myself to the
precise details herein described or delineated, but that what I believe to be
novel and original, and claim as the Invention secured to me by and in terms of
the bereinbefore in part recited Letters Patent is,-
1. The constructing of compound marine engines so as to expand the steam
through three stages, two cylinders being employed for the third stage, and the
several parts being arranged substantially as herein before described.
2. The arranging or combining together of the main parts of compound marine
steam engines substantially in the improved manner hereinbefore described as the
first modification.
3. The arranging or combining together of the main parts of compound marine
steam engines substantially in the improved manner hereinbefore described as the
second modification.
4. The arranging or combining together of the main parts of compound marine
steam egines substantially in the improved manner hereinbefore described as the
third modification.
In witness whereof, I, the said Alexander Carnegie Kirk, have hereunto set
my hand and seal, this Eighth day of August, in the year of our Lord One
thousand eight hundred and eighty one.
ALEXANDER.C. KIRK. (L.S.)