IMPROVEMENTS IN STEAM ENGINES
Year: 1853

page_text: LETTERS PATENT to John Scott, junior, and George William
Jaffrey, both of Greenock, in the County of Renfrew, North
Britain, Engineers, for the Invention of "IMPROVEMENTS IN STEAM
ENGINES
Sealed the 15th July 1853, and dated the 28th March 1853.
PROVISIONAL SPECIFICATION left by the said John Scott, junior,
and George William Jaffrey at the Office of the Commissioners
of Patents, with their Petition, on the 28th March 1853.
We, JOHN SCOTT, jun', and GEORGE WILLIAM JAFFREY, both of
Greenock, in the County of Renfrew, North Britain, Engineers, do
hereby declare the nature of the said Invention for "IMPROVEMENTS
IN STEAM ENGINES" to be as follows:-
This Invention relates especially to the obtainment of compactness
and efficiency of action in engines adapted for screw propulsion and
other purposes, wherein the peculiar advantages of the class are promi-
nently felt. When arranged for this purpose the condenser is made to
form the basis of the engine frame. It stands in the keel line of the

page_text: ship, and is cast with an angular ridge to sustain the pair of steam
cylinders, which are inverted, and set at or about an angle of 45°. Each
piston has two rods passing out at the lower end of each cylinder to a
single cross head, working in inclined guides bolted to the cylinder cover
or ends. From each end of this cross led a connecting rod passes up
to an overhead first motion shaft, carrying a pair of large spur wheels
set at some distance asunder on the shaft, and embracing the whole
mass of the machinery. On the outside of each spur wheel is a crank
pin, and the two opposite rods on each side or end of the engine are
jointed to the same crank pin. The two spur wheels respectively gear
with two pinions keyed on the main screw shaft which runs along the
keel line beneath the condenser. The upper closed ends of the cylinders
are bound together by arched cross beams and angular blocks, which
serve as pedestals for spur wheel shafts passing across from cylinder to
cylinder athwart ship, and these beams carry the valve, gear, shafts, &c.
The air pumps, two in number, are both on one side or end of the
engine, and are slightly inclined upwards towards the centre line of
the ship. They are on the "trunk" principle, and are worked from
one of the crank pins by means of a single large eccentric set upon the
pin, and contrived to reduce the throw to suit the requirements of the
pumps. Each trunk-plunger has a radius bar as a guide, and this bar
answers as well to work the feed and bilge pumps beneath. The two
views annexed represent a side elevation and plan of one modification
of these engines, as adapted for a screw steamer.
SPECIFICATION in pursuance of the conditions of the Letters Patent.
filed by the said John Scott, junior, and George William Jallrey,
in the Great Seal Patent Office, on the 28th September 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we,
JouN SCOTT, junior, and GEORGE WILLIAM JAFFREY, both of Greenock,
in the County of Renfrew, North Britain, Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-eighth day of March, in the

page_text: year of our Lord One thousand eight hundred and fifty-three, in the
sixteenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Scott, junior, and George William
Jaffrey, Her special licence that we, the said John Scott, junior, and
George William Jailrey, our executors, administrators, and assigns, or
such others as we, the said John Scott, junior, and George William
Jaffrey, our executors, administrators, or assigns, should at any timo
agree with, and others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN STEAM ENGINES," upon the condition (amongst
others) that we, the said John Scott, junior, and George William Jaffrey,
by an instrument in writing under our hand and seal, should par-
ticularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and cause the same to
be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that we, the said John Scott, junior, and George
William Jaffrey do hereby declare the nature of our said Invention,
and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement, reference
being had to the accompanying drawings, and to the letters and figures
marked thereon, that is to say:
Our said Invention relates especially to the obtainment of compact-
ness and efficiency of action in such engines as are mainly adapted for
screw propulsion, and other purposes wherein the peculiar advantages
of the class are prominently felt. When arranged for this purpose the
condenser is made to form the basis of the engine frame. It stands in
the keel line of the ship, and is cast with an angular ridge to sustain
the pair of steam cylinders, which are inverted and set at or about
an angle of 45 degrees with the vertical line. Each piston has two
rods passing out at the lower end of each cylinder to a single cross
head working in inclined guides bolted to the cylinder covers or ends.
From each end of this cross head a connecting rod passes up to an

page_text: overhead first motion shaft, carrying a pair of large spur wheels set at
some distance asunder on the shaft, and embracing the whole mass of
the machinery. On the outside of each spur wheel is a crank pin, and
the two opposite rods on cach side or end of the engine are jointed to
the same crank pin. The two spur wheels respectively gear with two
pinions koyed on the main scrow shaft, which runs along the keel line
beneath the condenser. The upper closed ends of the cylinders are
bound together by angular blocks of cast iron, which serve as podestals
to carry the spur wheel shaft, as wel as by arched cross beams passing
across from cylinder to cylinder athwart ship, and these beams carry
the valve gear shafts and other details. The air pumps, two in number,
are both on one side or end of the combined engine, and are slightly
inclined upwards towards the centre line of the ship. They are on the
"trunk" principle, and are worked from ono of the crank pins by
means of a single large eccentric set upon the pin, and contrived to
reduco the throw to suit the requirements of the pumps. Each trunk-
plunger has a radius bar as a guide, and this bar answers as well to
work the feed and bilge pumps beneath.
The drawing, Sheet I, attached hereunto, represents a transverso
section of a steam ship, as fitted up with a pair of these our improved
engines, which are consequently delineated in complete front or end
elevation in working order. Sheet 2, of our drawings is a correspond-
ing plan of the engines. In this arrangement the ship's floor, on which
the engines rest as a base, is at A, and on this is placed the condenser B,
as the main foundation of the entire machinery; and for the purpose
of securing superior steadiness, the single casting of which it is composed
is extended out in the keel line of the ship, as at C. The condenser
is cust with a double angular or ridged top, as at D, where suitable
flanges are formed for the reception of corresponding flanged surfaces E,
on the steam cylinders F, and in this manner the steam cylinders are
firmly bolted down at the angle at which they are intended to work.
The cylinders are inverted, that is to say, their blank ends G, are
uppermost, and they are connected together at this part by the double
angular casting II, fitted into the angular space between the cylinder
ends, and bolted down thereon to combine the whole details. This

page_text: angular casting also carries the pedestal bearings for the main first
motion shaft, I, which is disposed parallel with and directly over the
keel line of the ship. The piston of each cylinder has two piston
rods J, working through stuffing boxes in the lower end of the cylinder,
and disposed in the same horizontal plane; the projecting extremities
of the two rods in each case being cottered into a long cross head K.
This cross head has near each end a slide block L, fitted to work in the
inclined open guide frames M, two of which are bolted to the lower
end of each cylinder for this purpose, whilst they are additionally
steadied and supported by bracket pieces N, projecting downwards for
bolting upon pedestal pieces O, on the sole plate. Each guide frame M,
is in two longitudinal pieces, and the outer ends of these pieces are
further connected together by bolts passed through deep eyes P. The
cross head projects considerably through the guide frame on each side,
and each end of the cross head is formed into a journal to receive the
jointed end Q, of the long connecting rod R, passing thence to actuate
the main first motion shaft. In this way each piston works a pair of
these connecting rods, just as if a single rod were used. The first
motion shaft I has keyed upon each end of it a spur wheel S, these
two wheels being thus made to embrace the entire mass of the
machinery; on the outside of each wheel is a joint stud or crank pin T,
and the two opposite rods on each side or end of the engine are
jointed to the same crank pin. This is effected by making the stud
pins of an increased length, and arranging the two rods from one
cylinder to work close up to the exterior faces of the spur wheels,
whilst the other two rods are just as much clear of the wheels as is ne-
cessary to allow of the first-mentioned rod, eyes, or joints working
within them. In this way two crank pins answer for all the four con-
necting rods. The main shaft I, is conveniently placed in the angular
recess formed by the two upper ends of the cylinders; and the spur
wheels S, upon it, each gear with a corresponding spur pinion U, fast
on the screw shaft V, beneath. This forms a duplex system of gearing
for getting up the speed and actuating the propeller shaft, and, as the
two spur wheels are a considerable distance asunder, the double plan of
connection produces a much more satisfactory and generally better

page_text: balanced driving action than the ordinary single plan of gearing. An
arched cross beam W, is placed on each side, just within each spur
wheel, and is bolted down by end flanges to corresponding flange
pieces X, on the upper ends of the valve casings; these arched pieces
have cach two pedestal bearings Y, Z, as end supports for the slide
valve rocking shafts a, b, which are cach cranked at the centre, as
at c, d; connecting rods e, being passed in opposite directions from these
cranks to the spindles of the steam cylinder slide valves working in
the valve chests, on the upper sides of the steam cylinders. A short
lever, is also forged upon each of these rocking shafts, each lever
having a lateral stud pin, as a joint for the connection of the upper
end of a short eccentric rod h, passing up from an eccentric i, on the
main first motion engine shaft 1. In this way the slide valve of each
cylinder is worked from its corresponding eccentric on the main shaft;
and to enable the rocking levers, and from them the slide valves, to bo
worked by hand in starting and stopping, or on other occasions, the
rocking shaft a, is formed with a perforated swell j, for the insertion of
a hand lever; and a box lever piece is also set on the same shaft at K,
for a similar purpose. The lever k, is loose upon the shaft a, and it
carries another arm linked by a connecting piece k, with a short lever
fast on the opposite shaft b, at j. In this way the engine man, when
standing next the shaft a, has the valves for both cylinders under
complete command. Each eccentric, has a disengaging hand lever 1,
cranked at its lower end, to clear the slotted projecting piece l', set on
the side of the deep collar connecting piece m, of the eccentric, into
which the lower end of the rod h, is inserted. The hand lever 1, turns upon
the stud centre, on the side of the piece m, and it carries the short lever
piece o, which is jointed at the outer end to a short link in the slotted
piece. This link is again connected to an engaging pin, passing
through the piece l', and entering the collar m, where it can be
engaged at pleasure with a hole in the rod . The steam is supplied
to the valve chest on each side by an elbow branch pipe p, which
conveys the steam into a stop or expansion valve chest g, at the lower
corner of the slide valve chest; the exhaust steam passes off to the
condenser through suitable thoroughfares, cast round both sides of

page_text: the cylinder. The engines have two air pumps s, set in an inclined
position, both on one side of the engines, being bolted to the sole or
base plate by their foot branches t, whilst their upper ends are con-
nected together across the screw shaft line by two arched brackets u.
The air-pump plungers v, as well as the corresponding parts of all the
pumps about the engines, are of the "trunk" class; the hollow
trunks, or tubular pistons, work through suitable stuffing boxes in the
upper ends of the pump barrels, their actuating connecting rods w,
being jointed at their lower ends to stud pins in the bottoms of the
plungers. The upper ends of the rods w, are similarly jointed at æ, to
the lower forked joint strap ends of the long eccentric rods y, z. This
junction is effected in each case by a long transverse stud pin 1,
passed through the joint eyes of each piece, as well as through similar
forked joint eyes in the upper ends of the bent levers 2. The lower
ends of these bent levers 2, are also formed with forked or double eyes,
by which the two levers are set on a single stud 3, as
a fixed centre,
The levers 2,
this stud being carried by the arched cross beams u.
thus serve as parallel motion radius bars for the air pumps; and they
answer, at the same time, as the means of working the bilge and feed
pump 4, 5. These pumps stand vertically upon the sole plate, into
which they are recessed, to bring them to a more convenient level,
being supported on the sole plate by annular flanges 6, cast on the
pump barrels. Their plungers 7, 8, are made in the same way as the
air pump plungers; and their connecting rods 9, 10, are jointed by
strap ends at 11, 12, to about the centres of the levers 2. Both the air
pumps, together with the bilge and feed pumps, are worked from the
single connecting rod stud T, of the spur wheel on that side of the
engines; but as the throw of this stud would be too great for the action
of the pumps, the length of movement is reduced by setting an eccen-
tric 13, upon the working stud, so as to bring the actual working
centre of the motion nearer to the axial line of the main shaft I. This
arrangement consists, indeed, of the enlargement of the diameter of
the acting stud, but with an eccentric disposition as regards the axial
line of the stud, the working centre being thus brought as much nearer
to the axial line of the main shaft I, as is due to the amount of eccen-

page_text: tricity existing between the eccentric's real centre and the centre of its
carrying stud. One of the pump eccentric rods y, is formed in one
piece with the lower half of its eccentric ring. The other rod, is
jointed at 14, to the same half ring. In this instance the slide valves
are combinations of the usual four-ported class, with the equilibrium or
balanced pressure valve.
By this arrangement of steam engine the whole of the working
machinery is compressed into a small space, and everything is well
bound down upon the condenser as a solid base. The use of the
double set of piston rods conveys the piston movement to the cross
heads with superior steadiness, and with a more direct strain than
usual; whilst the increased length of connecting rod gained by the
return system materially improves the working of the engine.
Having now described and particularly ascertained the nature of our
said Invention, and the manner in which the same is or may be used
or carried into effect, we may observe, in conclusion, that we do not
confine or restrict ourselves to the precise details or arrangements
which we have had occasion to describe or refer to, as many variations
may be made therefrom without deviating from the principles or
main features of our Invention; but what we consider to be novel and
original, and therefore claim as the Invention secured to us by the
herein-before in part recited Letters Patent, is,-
First, the general arrangement and construction of steam engines,
as herein-before described.
Second, the system or mode of fastening down and carrying the
steam cylinders upon the condenser base plate, as herein-before
described.
Third, the application and use of the duplex system of wheel and
pinion gearing for actuating the second motion shaft.
Fourth, the system or mode of working the air pumps and bilge
and feed or other pumps of steam engines combined by means of
vibrating radius levers, as herein-before described.
Fifth, the system or mode of working the minor pumps of steam
engines by means of the radius levers of the air pump movement.
Sixth, the arrangement and construction of steam engines with one,

page_text: two, or more piston rods to each piston, actuating the driven shaft by
means of back or return connecting rods.
In witness whereof, we, the said John Scott, junior, and George
William Jaffrey have hereunto set our hands and seals, this
Twenty-fourth day of September, in the year of our Lord One
thousand eight hundred and fifty-three.
JOHN SCOTT, J.
J. (L.S.)
GEORGE WILLIAM JAFFREY. (L.S.)