IMPROVEMENTS IN THE CONSTRUCTION AND ARRANGEMENT OF MARINE STEAM ENGINES
Year: 1860

page_text: LETTERS PATENT to Marc Antoine François Mennons, of the British
and Foreign Patent Offices, 39, Rue de l'Echiquier, Paris, in the Empire
of France, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION AND
ARRANGEMENT OF MARINE STEAM ENGINES."-A communication from Vincent
Gâche, Sen'., residing at Nantes (Loire Inférieure).
Sealed the 27th September 1860, and dated the 21st July 1860..
COMPLETE SPECIFICATION filed by the said Marc Antoine François-
Mennons at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 21st July 1860, pursuant to the 9th Section of
the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL. COME, I, MARC
ANTOINE FRANÇOIS MENNONS, of the British and Foreign Patent Offices, 39,
Rue de l'Echiquier, Paris, in the Empire of France, send greeting.
WHEREAS I am in possession of an Invention for." IMPROVEMENTS IN THE
CONSTRUCTION AND ARRANGEMENT OF MARINE STEAM ENGINES," communicated:
to me by Vincent Gâche, Sen'., residing at Nantes, (Loire Inférieure,) and
have petitioned Her Majesty to grant unto me, my executors, administrators,.
and assigns, Her Royal Letters Patent for the same, and made solemu.
declaration that it is a communication:

page_text: NOW KNOW YE, that I, the said Marc Antoine François Mennons, do
hereby declare that the following Complete Specification under my band and seal
fully describes and ascertains the nature of the Invention, and the manner
in which the same is to be performed, reference being had to the accom-
panying Drawings, and to the letters marked thereon (that is to say) :-
Till within a recent period the consumption of fuel in marine engines has
been from forty to fifty per cent. above that of well constructed engines on
land, and notwithstanding the numerous modifications introduced from time
to time the difference in favor of the latter still remains very great.
The object of the present improvements is to remedy the two main defects
to which this state of inferiority may be ascribed, viz., the insufficiency of the
casings and the high tension of the steam at the moment of its entry into the
condenser.
In land engines the length of stroke which may be obtained permits a
reduction of the surfaces of the piston, so that the changes of temperature to
which the latter is subjected exert but little influence on the steam, which
may then advantageously act by expansion to produce its working power to
the utmost limit. In marine engines the case is widely different; the cylinders,
the diameter of which compared with the length of stroke is very great, offer
a much larger amount of cooling surface; from whence it follows that the
volume of steam before its expansion represents but a feeble proportion of the
weight of steam introduced, and in reducing to ths the ordinary intro-
duction at ths of the piston stroke the power of the engine is lowered
without giving rise to an appreciable economy of fuel. The impossibility of
employing powerful fly wheels to regulate the expansive working of the steam
renders it moreover necessary (notwithstanding the coupling of the engines),
to maintain the final pressure at a comparatively high degree of tension, so
that to the disadvantages above noted must be added the heavy loss resulting
from the condensation of the steam while it still retains a considerable amount
of dynamical power.
In the arrangement bereafter described the loss of heat during the working
is obviated by the circulation of steam, not only round the cylinders and in
their bottoms and covers, but also in the pistons, and to economise as far as
possible the heat of the steam at the moment of its passage to the condenser a
first injection is made with the water of the air pump well, and the product
of this partial condensation collected in a recipient is employed to feed the
boiler. To obtain the maximum power from a given weight of steam in
working expansively without the aid of a fly wheel two cylinders of different

page_text: alameters are employed in each engine of the present combination. By this
means the final pressure on the main piston being increased by that exercised
on the lesser one the limit at which the sum of the pressures becomes equal
to that of the resistances is much more remote than when one cylinder only is
adopted.
Figures 1, 2, Pl. 1, of the accompanying Drawings represent a combination
applicable to screw steamers.
Figures 3, 4, Pl. 2, represent a horizontal direct connection arrangement,
also applicable to screw steamers.
Figures 1, 2, Pl. 2, represent a combination for paddle vessels; and
Figures 3, 4, Pl. 1, represent the steam superheating apparatus.
Each engine comprises two adjoining superposed cylinders, as in A, A,
Fig. 1, Pl. 1, and Fig. 2, Pl. 2. The piston rod attached to the beam B
transmits the movement to the driving shaft C, by means of the main con-
necting rod D. The cylinders are provided with casings for the circulation of
which from thence passes into the bottom and cover by a series of
communicating apertures. The steam is also admitted into the main piston A',
by means of the hollow rod a communicating with the boiler.
the steam,
The following advantages are derived from the superposition of the cylinders.
1stly, coupling of the two pistons to a single connecting rod.
2dly, employment of single transmission gear as if one cylinder only
existed.
3dly, distribution of the steam to both cylinders by a single slide valve
and excentric.
The reversing motion is effected by means of the piston of the steam cylin-
der G. The communication of this cylinder with the steam and the condensers
being opened by the distributing cock g, the pressure on the piston balancing
the pressure on the slide valves the latter may be readily worked by the lever.
The condenser H, the well H', and the air reservoir form one piece, which
serves as framing to the pedestals of the beam B. The stop valve I checks the
cooling of the cylinder by preventing the gases of the condenser from flowing
into the pipes after the passage of the steam. The cross bar of the piston rod
of the air-pump J, sets in motion two feeding pumps K and K'. The first
(double acting) draws the water from the well H¹ by the pipe L, and throws
it into the capacity L', where it takes up a large portion of the heat of the
steam passing into the condenser. This superheated water is again taken up
by the piston of the same pump in passing by the suction pipe M, and is
afterwards carried into the boiler by the emission pipe M². The temperature
to which it is raised by this process produces a considerable economy of fuel.

page_text: Plate-1, Figures 1, 2, 3, 4.-A, A, steam cylinders; B, beam; C, driving
shaft; D, main connecting rod; A', main piston; a, hollow rod for the intro-
duction of the steam to the main piston; E, connecting rod; F, distributing
slide; G, small starting cylinder; g, distributing cock of the starting cylinder ;
H, condenser; H', hot water well; I, stop valve of the steam emission pipe;
J, air pump; K, feed pump; K', bilge pump for casings; L, suction pipe of
the feeding pump; L', capacity for reheating the feed water by contact with
the steam; M, feed pump suction pipe communicating with the capacity L';
M³, boiler emission pipe; N, cylinder placed in the steam chest and containing
the superbeating apparatus Q; O, lever coupled to the connecting rod of the
starting cylinder and working the guides P of the slide valves; Q, steam
superheating apparatus composed of horizontal tubes; R, valve for the intro-
duction of the steam to the apparatus Q; S, emission valve for the steam
after its passage through the superheating apparatus; T, valve for admitting
steam to the engines without passing it through the superheating apparatus.
Plate 2, Figures 1, 2.-A, A, steam cylinders; B, cross bar of the piston
rods; C, driving shaft; D, main connecting rods; A', main piston; a', hollow
rod for blowing off the water of the piston; a, hollow rod for admitting steam
into the main piston; E, connecting rod; F, distributing slide; G, small
starting cylinder; H, condenser; H', hot water well; J, air-pump; K, feed
pump; L', capacity for reheating the feed water by contact with the steam;
M, steam pipe.
Plate 2, Figures 3, 4.-A, A, steam cylinders; B, beam; C, driving shaft ;
D, main connecting rod; E, connecting rod; G, starting cylinder; H, con-
denser; H, hot water well; J, air pump; K, feed pump; K', bilge pump
for casings; L', capacity in which the feed water is reheated by contact with
the steam.
Having thus described the nature of the said Invention and the manner of
carrying it into effect, I declare that what I claim is :-
1stly, the application to marine steam engines of two adjoining cylinders with a
single slide valve and with pistons attached to the same rod, substantially as
above described and represented in Figs. 1, 2, Pl. 1, and 1, 2, 3, 4, Pl. 2.
2lly, the heating of the main piston by the steam from the boiler as above
described and by the arrangement represented in Fig. 1, Pl. 1, and 2, Pl. 2.

page_text: Sdly, the application of the valve to the extremity of the condensation pipe,
as shewn in Fig. 1, Pl. 1.
4tbly, the peculiar arrangement of the feeding pump, which after throwing
the condensation water over the steam returns it to the boiler as above described
and represented in Fig. 1, Pl. 1.
5thly, the peculiar arrangement of the steam superheating apparatus, as
represented in Figs. 3, 4, Pl. 1, which apparatus instead of being placed in
the smoke box or in the chimney, as is generally practised, is enclosed in a
cylinder placed in the steam chest, by which means a considerable waste of
heat is avoided.
In witness whereof, I, the said Marc Antoine François Mennons, have
hereto set my hand and seal, this Eighteenth day of July, in the year
of our Lord One thousand eight hundred and sixty.
M. F. MENNUNS. (L.S.)