IMPROVEMENTS IN THE CONSTRUCTION, ARRANGEMENT, APPLICATION OF STEAM ENGINES
Year: 1868

page_text: AND
ETTERS PATENT to George Davies, of No. 1, Serle Street, Lincoln's
Inn, in the County of Middlesex, and No. 87, St. Vincent Street,
in the City of Glasgow, Civil Engineer and l'atent Agent, for the
Invention of "IMPROVEMENTS IN THE CONSTRUCTION, ARRANGEMENT,
APPLICATION OF STEAM ENGINES."A communication from abroad by
Ferdinand Michel Ernest Nillus, of Paris, in the Empire of France,
Engineer.
Sealed the 18th September 1868, and dated the 27th March 1868.
PROVISIONAL SPECIFICATION left by the said George Davies at the
Office of the 'Commissioners of Patents, with his l'etition, on the
27th March 1868.
I, GEORGE DAVIES, of No. 1, Serle Street, Lincoln's Inn, in the County
of Middlesex, and No. 87, St. Vincent Street, in the City of Glasgow,
Civil Engineer and Patent Agent do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE CONSTRUCTION, ARRANGEMENT, AND
I, GEORGE DAVIES, of No. 1, Serle Street, Lincoln's Inn, in the County
of Middlesex, and No. 87, St. Vincent Street, in the City of Glasgow,
Civil Engineer and Patent Agent do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE CONSTRUCTION, ARRANGEMENT, AND

page_text: APPLICATION OF STEAM ENGINES," (a communication to me from abroad by
Ferdinand Michel Ernest Nillus, of Paris, in the Empire of France,
Engineer,) to be as follows:-
These improvements in the construction and arrangement of steam
engines have particularly for their object to cause them to occupy
less space, not to require any abutment other than the bed or sole
plate on which they rest, at the same time that they require very
little foundation notwithstanding the power which may be given them,
and, lastly, to form a compact solid (though comparatively light) mass
without complication of mechanical organs,. which latter occurs in a
great number of systems, and more especially in the duplex cylinder
engines constructed on what is known as the "Wolff" system.
The principal advantages of this present system are as follows:-
Firstly. A single excentric motion serves for both valves.
Secondly. There is a perfect equilibrium, because the organs of the
two cylinders counterbalance each other.
33
Thirdly. By the fact of this equilibrium the dead point becomes
almost null.
Fourthly. The steam passes directly from the top of the small
cylinder into the bottom of the large one and vice versa, that is to
say, from the bottom of the small cylinder to the top of the large
one on the return stroke of the pistons; this arrangement renders
useless the expensive and inefficacious employment of regenerators,
reheaters, and the like, and above all it avoids compression.
Fifthly. The space occupied by the engine is reduced to its simplest
dimensions.
Sixthly. Owing to its simplicity and the reduction of the organs the
apparatus is lighter and less costly.
Seventhly and lastly. The economy of fuel must be greater with this
system than with those hitherto known on account of the advantages
above mentioned.
I would remark in addition that the engine when arranged for the
purposes of navigation presents the following novelties:--
Firstly. A jacket or envelope in plate iron, which surrounds the
cylinders, and which contains steam at the same pressure as that
furnished by the generators.

page_text: Secondly. A combination of slide valves to establish communication
between the cylinders.
The arrangement of the engine for marine purposes, and the
combinations of which it is susceptible for propelling vessels with
double screws, are as follows:-Two cylinders are used, one larger in
diameter than the other, as on the "Wolff" system; the piston rods
of these two cylinders actuate by means of crossheads and links
balance beams, to the ends of which the said links are attached;
the beams oscillate on a fixed centre. The same eccentric motion
actuates the slide valves of both cylinders; for this purpose the valve
rods are attached to the extremities of a small balance beam vibrating
on a fixed point. At the side of the valve rod of the small cylinder
is a reversing slide, the ends of which are attached to the two
eccentric rods, being a very simple arrangement for reversing the
engine. All the framing of, the engine is hollow; the central part,
that is to say, that part situated between the two cylinders serves as
a condenser. The slide valve which opens and closes communication
between the two cylinders is of a peculiar form; it is composed of
two pistons fixed on the same rod, and having double openings corre-
sponding with others formed in the cylindrical cavity, in which, the
two pistons move, and which serves as a valve box; this valve is moved
by cams so arranged as to avoid shocks and noise. At one side (and
arranged symmetrically as regards a vertical plane passing through the
axes of the two cylinders) is a double slide valve, which serves as a
steam admission valve for the small cylinder, and an exhaust for
the large one; this slide valve is composed of two shells placed
back to back, and between which are placed springs to press them
against their respective valve faces; the two shells are connected to
the same rod actuated by the small balance beam above mentioned.
The cylinders and valve casings are enclosed in a jacket of plate iron
capable of resisting, the same pressure as the boiler, and which is
supplied with steam from the latter to prevent the cooling of the
various organs; this plate iron is protected by two successive envelopes
of felt and wood.
For propelling vessels with two screws it is proposed to employ
an arrangement of six cylinders, four small ones, and two large ones,
the latter being in the centre, and each having a small one on each
side, The capacity of the large cylinders with regard to the small is as

page_text: four to one.
The horizontal shafts of these engines thus connected
may be rendered independent by means of couplings of any known
construction.
I would observe that the distribution of the steam may be effected
in two manners, firstly, by means of the shell valves alone, in which
case the boxes which enclose them are necessary. Secondly, with the
shell valves and cylindrical valves combined; in this case the leaf of
the shell valve has sufficient lap not to uncover the end orifices.
The box which encloses the shell valves can then be dispensed with,
and the steam which the plate iron envelope encloses will then
surround the whole of the distributing apparatus.
Vessels with two screws may also be driven by the single arrangement,
that is, with four cylinders, two large and two small.
and two small. In order to
obtain a sufficient diameter for the screws the screw shafts will have
to be placed slightly oblique to each other in some vessels.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Davies in the Great Seal Patent Office on
the 26th September 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
DAVIES, of No. 1, Serle Street, Lincoln's Inn, in the County of
Middlesex, and No. 87, St. Vincent Street, in the City of Glasgow, Civil
Engineer and Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh day of March, in the
year of our Lord One thousand eight hundred and sixty-eight, in the
thirty-first year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said George Davies, Her special licence
that I, the said George Davies, my executors, administrators, and assigns,
or such others as I, the said George Davies, my executors, adminis-
trators, and assigns, should at any time agree with, and no 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 THE CON-
STRUCTION, ARRANGEMENT, AND APPLICATION OF STEAM ENGINES, (a communi-

page_text: cation to me from abroad by Ferdinand Michel Ernest Nillus, of Paris, in
the Empire of France, Engineer,) upon the condition (amongst others)
that I, the said George Davies, my executors 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 George Davies, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement in writing, and on reference to the accompanying
Sheets of Drawings, that is to say:
These improvements in the construction and arrangement of steam
engines have particularly for their object to cause them to occupy
less space; not to require any abutment other than the bed or sole
plate on which they rest at the same time that they require very
little foundation notwithstanding the power which may be given them;
and lastly to form a compact solid (though comparatively light) mass
without complication of mechanical organs, which latter occurs in a
great number of systems and more especially in the duplex cylinder
engines constructed on what is known as the "Woolff" system.
The principal advantages of this present system are as follows:-
Firstly. A single eccentric motion serves for both valves.
Secondly. There is a perfect equilibrium, because the organs of the
two cylinders counterbalance each other.
Thirdly. By the fact of this equilibrium the "dead point "becomes
almost null.
Fourthly. The steam passes directly from the top of the small
cylinder into the bottom of the large, one, and vice versa, that is to
say, from the bottom of the small cylinder to the top of the large
one on the return stroke of the pistons; this arrangement renders
useless the expensive and inefficacious employment of regenerators,
reheaters, and the like and above all it avoids compression.
Fifthly. The space occupied by the engine is reduced to its simplest
dimensions,

page_text: Sixthly. Owing to its simplicity and the reduction of the organs
the apparatus is lighter and less costly.
Seventhly and lastly. The economy of fuel must be greater with
this system than with those hitherto known on account of the advantages
above mentioned.
I would remark in addition that the engine when arranged for the
purposes of navigation presents the following novelties:-
Firstly. A jacket or envelope in plate iron which surrounds the
cylinders, and which contains steam at the same
furnished by the generators.
pressure as that
Secondly. A combination of slide valves to establish communication
between the cylinders.
Such being the nature and object of the said Invention for "Improve-
ments in the Construction, Arrangement, and Application of Steam
Engines I will now proceed to describe more in detail the manner
in which the same is to be or may be performed or carried into practical
effect, and in order that the same may be distinctly understood, I
have annexed hereunto two Sheets of Drawings illustrative thereof, and
have marked the same with figures and letters of reference corre-
sponding with those in the following explanation thereof, that is to
say:
In Sheet 1 of the annexed Drawings Figure 1 represents a vertical
section (through the line 1-2, in Figure 2) of a marine engine con-
structed according to this Invention; Figure 2 is a corresponding plan
view seen partly in horizontal section; Figure 3 is a transverse section
through the line 3-4, in Figure 2.
A is the smaller cylinder and A' the larger one. The piston rods t
and t of these cylinders actuate the balance beams 6 by means of
the links C and C' attached to their extremities. These beams oscillate
on a fixed point T. The same excentric motion S acts upon the slide
valves of both cylinders. For this purpose the valve rods are attached
to the ends g and g' of a small heam the fixed point of which is at o;
at the side of the valve rod of the small cylinder is a reversing slide f
the extremities of which are attached to two excentric rods, a very
simple arrangement which allows of the engine moving in either
direction. All the framing of the engine is hollow the central part X
that is to say, the part situated between the two cylinders serves as

page_text: The slide valve which opens and closes communication
a condenser.
between the two cylinders A and A' is of a peculiar form; it is coin-
posed of two pistons p and p' fixed on the same rod. They have two
openings a, a', through them corresponding with others formed in the
cylindrical cavity in which the two pistons move and which serves
as a valve box. This valve is moved by cams so arranged as to avoid
shocks and noise. At one side (and arranged symmetrically as regards
a vertical plane passing through the axes of the two cylinders)- is a
double slide valve, which serves as a steam admission valve for the
small cylinder and an exhaust for the large one. This slide valve
is composed of two shells c and c' placed back to back, and between
which are interposed springs to press them against their respective
valve facings; the two shells are connected to the same rod actuated
by the small balance beam g, g', above mentioned. The cylinders and
valve casings are enclosed in a jacket Y of plate iron capable of resisting
the same pressure as the boiler and which is supplied with steam from
the latter to prevent the cooling of the various organs, this plate iron
is protected by two successive envelopes of felt and wood.....
:
Figures 4 and 5 (Sheet 2) represent in elevation and plan view a
diagram of an arrangement applicable to vessels with twin screws.
It will be seen that it comprises six cylinders four small
ones and
two large, the latter being in the centre and the others placed
symmetrically around them. The capacity of the larger cylinders with
regard to the small is as four to one. The horizontal shafts of these
engines thus connected may be rendered independent by means of
couplings of any known construction.
71
I would observe that the distribution of the steam may be effected
in two manners; firstly, by means of, the shell valves alone, in which
case the boxes which enclose them are necessary. Secondly, with the
shell valves and cylindrical valves combined; in. this case the leaf of
the shell valve has sufficient "lap not to uncover the end orifices.
The box which encloses the shell valves may then be dispensed with,
and the steam which the plate iron envelope encloses will then surround
the whole of the distributing apparatus. This combination is very good
inasmuch as it dispenses with the winding passages which wire-draw
and cool the steam, as the exhaust from the small to the large cylinder
takes place directly by means of the cylindrical valves, which latter
are actuated by cams so arranged as to avoid shocks and noise. I

page_text: would also remark that it is possible with a single engine, that is
with four cylinders, to give motion to two screws placed at the sides
of the vessel as will be seen on reference to the annexed Drawing.
Figure 6 represents the position assumed by the fore" couple relatively
to that of the "after"
either direction.
In the
couple Figure 7. The cranks M can turn in
space which exists between the engine A
and the screws H and H (Figures 8 and 9, Sheet 1, which represent
the plan or diagram of the keel) the shafts a and a' may be placed
obliquely for certain vessels in order to obtain a sufficient diameter
for the screws.
This combination constitutes an excellent application
of this system of engine to vessels with twin screws; each cylinder
has its own crank and the motion for the air pumps may be taken
from any convenient part.
I may here observe that the beams employed to connect the piston
rods may be dispensed with if desirable by coupling the crank pins
of each pair of cylinders by connecting rods B as shown at Figure 10
(Sheet 2). The shafts may be also coupled by means of two drums A
and A (as shown in plan and elevation at Figures 11 and 12) connected
together by metallic bands M of a number and strength proportioned
to the power to be transmitted. The bands are crossed to give rotation
in opposite directions. The drums should have a circumference about
equal to the throw of the cranks. These two arrangements are intended
to dispense with the balance beams, and at the same time to preserve
the equilibrium of the moving parts.
Lastly. The pairs may be deprived of balance beams and all inter-
mediate connections, in which case they work by the distribution of the
Each pair is complete in itself (small and large cylinder) by
reason of the said distribution.
steam.
66
Having now described the nature and object of the said Invention
for Improvements in the Construction, Arrangement, and Application
of Steam Engines together with the manner in which the same is
to be or may be performed or carried into practical effect, I would
remark in conclusion that I claim as the Invention communicated to
me by the aforesaid Ferdinand Michel Ernest Nillus.
First. The different arrangements and combinations of engine
composed in pairs of one cylinder for the introduction of steam at a
greater or lesser pressure and of another cylinder for expansion, the

page_text: cranks being joined together in pairs by balance beams or connecting
rods.
Secondly. The application of these engines to propel vessels with
twin screws.
Thirdly. The arrangement of the plate iron jacket containing steam
at the same pressure as that of the boiler.
Fourthly. The combination of distributing valves to establish com-
munication between the cylinders and the admission of steam to the
small cylinder and the exhaustion of the steam from the large cylinder.
Fifthly. The general arrangements for driving the screws by inclined
shafts connected to the driving shafts either directly or by means of
any kind of couplings.
And, sixthly. The different means of combining four cylinders to
drive two screws by the aid of the arrangements above described.
In witness whereof, I the said George Davies, have hereunto
set my hand and seal, this Twenty-sixth day of September, in
the year of our Lord One thousand eight hundred and sixty-
eight.
GEORGE DAVIES. (L.S.)