IMPROVEMENTS IN MARINE STEAM ENGINES FOR DRIVING SCREW AND OTHER PROPELLERS
Year: 1859

page_text: LETTERS PATENT to Charles Sells, of Stockwell, in the County of Surrey,
Engineer, for the Invention of "IMPROVEMENTS IN MARINE STEAM ENGINES
FOR DRIVING SCREW AND OTHER PROPELLERS."
Sealed the 15th May 1860, and dated the 6th December 1859.
PROVISIONAL SPECIFICATION left by the said Charles Sells at the
Office of the Commissioners of Patents, with his Petition, on the
6th December 1859.
I, CHARLES SELLS, of Stockwell, in the County of Surrey, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
MARINE STEAM ENGINES FOR DRIVING SCREW AND OTHER PROPELLERS," to be
as follows:-
These improvements consist in an improved arrangement of horizontal
engine for screw propulsion, designed for the purpose of effecting great
economy of fuel by using the steam very expansively for obtaining a uniform
and equable power, and for obviating the vibratory motion at present com-
municated to the vessels by keeping all the moving parts as nearly as may be
in balance with regard to the vessel. For these purposes I employ three
cylinders, placed together side by side, the area of which should be increased
about or more than usual when intended for working with a great amount
of expansion. The cylinders have a three-throw crank shaft immediately in

page_text: front of them. Each cylinder has two piston rods, one passing below and one
above the shaft, connected to a cross head, with the connecting rod returning
back to the crank. Nearly opposite each of the outer cylinders is placed a
condenser, with its hot well, and with a horizontal air pump, which is worked
direct from the piston of the opposite cylinder. Each of the condensers and
air pumps serves for the condensation of the steam of its opposite cylinder,
and for one-half of the steam of the centre cylinder. By these arrangements
the whole of the working parts are kept well in view and easily accessible,
while at the same time a firm, compact, and well-balanced engine is obtained.
In order to cut off the steam at an early part of the stroke, and as close to the
cylinder as possible, and in order that the engine may be started readily at any
time, I dispense with the expansion valve ordinarily used, and proportion the
slide valve for cutting off the steam at about of the stroke of the piston,
with the means of causing it to cut off at any shorter period by an improved
apparatus, which will be also used for reversing and starting the engines. It
consists of a train of two or more wheels for communicating motion from the
main crank shaft to the crank or eccentric shaft for working the slides, and is
carried in a movable frame, which by being raised or lowered by suitable
means will cause the eccentric or crank shaft to revolve to the extent required
for effecting the operation intended. And as the opening of the ordinary slide
valve for the admission of the steam becomes very limited when proportioned
for cutting off the steam so carly I also employ an improved description of
slide valve, having one or more additional openings for the admission of the
steam, with corresponding ports in the cylinders, so as to obtain the required
amount of steam opening without increasing the area of the eduction ports.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Sells in the Great Seal Patent Office on the
6th June 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
SELLS, of Stockwell, in the County of Surrey, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of December in the year of our
Lord One thousand eight hundred and fifty-nine in the twenty-third year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Charles Sells, Her special licence that I, the said Charles
Sells, my executors, administrators, and assigns, or such others as I, the

page_text: ני
said Charles Sells, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after 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 "IMPROVE-
MENTS IN MARINE STEAM ENGINES FOR DRIVING SCREW AND OTHER PROPELLERS,"
upon the condition (amongst others) that I, the said Charles Sells, my execu
tors or administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly 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 I, the said Cliarles Sells, my do hereby declare the
nature of my said Invention, and in what manner the same is. to be.
performed, to be particularly described and ascertained in and by the
following statement thereof, reference being had to the Drawings hereunto
annexed, that is to say :-
My Invention consists in an improved arrangement of horizontal engine for
screw propulsion, designed for the purpose of effecting great economy of fuel
by using the steam very expansively for obtaining a uniform and equable
power, and for obviating the vibratory motion at present communicated to
vessels from the action of the engines when two only are used. For these
purposes I employ three cylinders, placed together side by side, the area of
which should be increased about or more than usual when intended for
working with a great amount of expansion. The cylinders have a three-throw.
crank shaft immediately in front of them. Each cylinder has two piston rods,
one passing above, and one below the shaft connected to a cross head, with
the connecting rod returning back to the crank. Nearly opposite each of the
two outer cylinders is placed a condenser, with its horizontal air. pump... The
air pumps are worked direct from the pistons of the opposite cylinder,. or by an
arm from one of the piston rods; each of the condensers and air pumps serves
for the condensation of the steam from its opposite cylinder, and for one-half
of the steam from the centre cylinder. In order to cut off the steam at: an
carly part of the stroke of the piston, and as close to the cylinder as possible,.
I dispense with the ordinary expansion valves, and adapt the slide valve for
that purpose, and employ an improved apparatus for shifting the position of
the eccentrics so as to be enabled to cut off the steam at the time.required.
This apparatus is also used as a starting and reversing gear, and consists of a

page_text: train of two or more spur wheels, mounted in a moveable frame for com
municating the motion from the spur wheel on the main crank shaft to a spu
wheel on the crank or eccentric shaft for working the slides; this frame may
be raised or lowered by suitable means, so as to cause the eccentric shaft to
revolve to the extent required for effecting the intended operation; and as tho
opening of the ordinary slide valve for the admission of the steam becomes
very much reduced when the lap is proportioned for cutting off the steam at
an early part of the stroke, I employ an improved description of slide valve,
having one or more additional facings, with the corresponding ports into the
cylinder for the admission of the steam, so as to obtain the requisite amount of
steam opening without increasing the area of the eduction openings.
In the Drawings hereunto annexed I have shewn my improved arrange-
ments of engines, and also the apparatus for shifting the eccentrics, together
with the improved description of slide valve.
Figure 1 is a side elevation, Figure 2 an end view partly in elevation and
partly in section, and Figure 3 a plan of my improved engine, fitted with the
ordinary injection condensers. A, A, A, are the three cylinders, placed side
by side with the three-throw crank shaft B in front of them; C, C, are the
piston rods, connected to the cross heads; D and E are the connecting rods
returning back to the crank, as in the ordinary double piston rod engine;
F, F, are the two condensers; and G, G, are the two horizontal air pumps,
with their foot and delivery valves and hot wells; H, H, are the two passages
for conveying the exhaust steam from the centre cylinder through the eduction
spaces of the outer cylinders to the main eduction pipes I, leading to the
condensers; K is the eccentric shaft for working the slides, which is driven
by the spur wheel L on the main crank shaft by means hereafter described;
M is the main steam pipe; and N is a shut off valve, to be used in lieu of the
ordinary throttle valves, to be worked by levers from the starting platform, in
order readily to regulate the admission of steam to the engines, or to shut it
off when required.
Figure 4 is a side elevation, Figure 5 an end view partly in elevation and
partly in section, and Figure 6 a plan of my improved engine, fitted with
surface condensers, and the necessary cold water pumps. In this arrangement
I work the air pump by an arm from one of the piston rods of the outer
cylinders, and the cold water pumps, which are also placed opposite; the two
outer cylinders are worked by rods direct from the pistons. A, A, are the
surface condensers, with the water circulating between the tubes, while the
steam is condensed within them; B, B, are the two air pumps worked from
the piston rods by the arms C, C; D, D, are the cold water pumps, with their

page_text: foot and delivery valves, worked by rods direct from the pistons of their
opposite cylinders; E, E, are the suction pipes, leading from the side of the
vessel; and F, F, are the delivery pipes leading to the lower parts of the
surface condensers by the passage way G, which has an opening at its lower
part, while the hot water passes away from the top by the passage way H,
and over board by the discharge pipe I. The other parts of the engines arc
similar in arrangement to those illustrated in Figures 1, 2, and 3.
These two plans form firm and compact arrangements of engines especially
suited for working the steam with a great amount of expansion, as by the
employment of three cylinders with their cranks placed at an angle of 120°
with each other the power is rendered nearly uniform,. The whole of the
working parts are kept well in view, and are easy of access at all times while
at work, which is very essential in quick working engines, while at the same
time much of that unpleasant motion felt in screw vessels will be obviated, as
the centre of gravity of the moving parts is always nearly in the same position
with regard to the vessel.
Figure 7 is an elevation, and Figure 8 a plan of the apparatus I use for
shifting the position of the eccentrics. I propose to proportion the slide valve.
to shut off the steam at of the stroke, when the valve is made to commence
opening the steam ports just at the beginning of the stroke of the piston or
when the crank is just passing its centre, and when required for starting the
engines the eccentrics may be set backwards, so as to allow the steam to dwell
on until about of the stroke, and when required to work with a greater
amount of expansion, they may be set forward, so as to cut off the steam at
the time required. The alteration in the amount of expansion may be effected
without materially altering the admission of the steam into the cylinder. A is
the spur wheel on the crank shaft, which gives motion by means of the spur
wheels B, B, mounted in the movable frame C, to the spur wheel D, on the
eccentric shaft E, which gives motion to the slide valves. It will be readily
seen that by lowering the frame C, which is guided at its upper and lower
ends, so as to keep the wheels properly in gear together, the eccentric shaft
will be caused to revolve in the direction shewn by the curved arrow, so that
the position of the eccentrics in relation to the crank may be altered at
pleasure by raising or lowering the frame; F, is a lever, attached by links to
the lower end of the frame, and which is adjusted by the screwed rod, and
hand wheel G. This apparatus is also used for reversing the engines, as the
cccentrics may be set forward the amount requisite for performing that
operation, in the manner described. I prefer also to use a short eccentric rod
as shown in the Drawing, arranged so as to compensate in some measure for

page_text: the irregularity in the time of cutting off the steam, caused by the limited
length of the ordinary connecting rod.
Figure 9 is a sectional view of an ordinary double ported slide valve, with
the additional steam facings A, A, and the additional steam ports B, B, by
which I obtain the requisite amount of steam opening when the lap is
increased so as to cut off the steam at an early part of the stroke.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I do not confine myself to
the particular details shewn in the Drawings; but what I claim is,—
First, the general arrangement of horizontal engines with three cylinders,
and with the air pump and condensers placed opposite the two outer cylinders.
as herein-before described.
Second, the improved apparatus herein-before described for altering the
position of the eccentrics so as to cause them to cut off the steam sooner or
later, and also for reversing the engines.
And, third, the improved form of slide valve having additional steam facings
with additional ports in the cylinder to compensate for the small width of
opening consequent upon giving the slide a great amount of lap, as hercin-
before described, and illustrated in the accompanying Drawings.
In witness whereof, I, the said Charles Sells, have hereunto set my
hand and seal, this Fourth day of Junc, One thousand eight hundred
and sixty.