CERTAIN IMPROVEMENTS ON STEAM ENGINES
Year: 1822

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARC
ISAMBARD BRUNEL, of Chelsea, in the County of Middlesex, Engincer, send
greeting.
WHEREAS His most Excellent Majesty King George the Fourth did,
by His Letters Patent under the Great Seal of that part of the United
Kingdom of Great Britain and Ireland called England, bearing date at West-
minster, the Twenty-sixth day of June, 1822, in the third year of His reign,
give and grant unto me, the said Mare Isambard Brunel, my exors, adñiors,
and assigns, His especial licence, full power, sole privilege and authority, that
I, the said Marc Isambard Brunel, my exors, adññors, and assigns, during
the term of years therein mentioned, should and lawfully might make, use,
exercise, and vend, within that part of the United Kingdom of Great Britain
and Ireland called England, the Dominion of Wales, and Town of Berwick-
upon-Tweed, my Invention of "CERTAIN IMPROVEMENTS ON STEAM ENGINES;" in
which said Letters Patent there is contained a proviso that if I, the said Marc
Isambard Brunel, shall not particularly describe and ascertain the nature of my
said Invention, and in what manner the same is to be performed, by an instru-
ment in writing under my hand and seal, and cause the same to be inrolled in
His Majesty's High Court of Chancery within six calendar months next and
immediately after the date of the said Letters Patent, that then the said Letters
Patent, and all liberties and advantages whatsoever thereby granted, shall utterly
cease, determine, and become void, as in and by the same, (relation being
thereunto had), will more fully and at large appear:

page_text: NOW KNOW YE, that in compliance with the said proviso, 1, the said
Marc Isambard Brunel, do hereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, are particularly
described and ascertained in and by the Drawings hereunto annexed, and the
following description thereof (that is to say) :-
I do declare that my improvements on steam engines are limited to those
used for the purpose of navigation; first, in the manner of disposing and com-
bining two engines so as to apply their powers. in the most direct way for pro-
ducing a rotary action; secondly, in the method of moderating and regulating
the movements of these engines, and producing an equable action in the
movement of these engines; thirdly, in the mode of condensing the steam;
fourthly, in certain adaptations to the boilers.
act.
In the first place, the disposition I adopt to produce the rotary action is by
placing the line of the powers in the direction to be at right angles, or nearly
so, with each other. Though the right angle is the most favorable position for
the respective powers, I do not confine myself to that angle only, as I may
contract or increase to a certain extent, as necessity may require. In the Fig. 1,
the engines being nearly at right angles with each other, the crank is a
solid double crank, as represented at A, Figs. 2 and 5, on which both engines
The marine engine represented with its parts by the Figures from
Number 1 to Number 23 inclusively as the plan of condensation, I adopt for
sea service every part of the said engines, therefore, disposed accordingly.
Fig. 1 represents the lateral elevation of the said engine; Fig. 2 a tran-
verse section of the vessel, shewing the position of the engine and the
boilers Fig. 8 a section of the steam cylinder and of the moderator; Fig. 4
a ground-plot of the engine with the boilers in their respective places; Fig. 5
a view of the steam cylinder, shewing the connexion with crank A, with the
moderator C, and with the air pump B. These Figs. exhibit the principle
characters of the engine, combining the four points adverted to. The direction
in which the powers act on the crank is too obvious to require further explana-
tion.
With respect to the regulating and moderating of the engine, it is
effected by an hydraulic apparatus C, Fig. 3, and 5, consisting of a pump, the
piston of which forces the water or any other fluid which might be employed
through an orifice, which can be contracted or enlarged by the action of a
governor, as in the engine now in question. This pump is connected with the
condenser. It has a suction pipe B, Fig. 1 and 3, and also an eduction orifice
F, Fig. 6. In the Fig. 6 is represented the regulating plug A, destined to
contract the arrear of the orifice B. It must be observed that the orifice B is
not to be closed entirely. It is proposed to allow a waste equal to about the

page_text: 35 part of the orifice, in order to avoid shocks by the sudden closing of the plug.
In order to facilitate the action of this plug under all degrees of pressure, it is
connected by a stem with a small piston C, fitted into a close chamber; the
stem of the plug being hollow allows of a certain quantity of the forced liquid
5 to escape through it, and to act on the back of this piston; and the plug being
thus balanced between two equal pressures, is easily acted upon by the governor.
The governor is connected with the rotary action of the engine by means of
small cog wheels B, B, Fig. 2, which I prefer to any other method of con-
nexion. As the common governor usually applied to land engines cannot act
regularly at sea, I modify the same in a way that will fit it for that particular
service. The Fig. 6 represents the marine or locomotive governor as at rest,
that is, when the engine works at the given rate. To fit this governor for that
peculiar service, it is indispensable that all effect of gravitating or any other
power, except centrifrugal force, be neutralised. This is done in the manner
represented in Fig. 6; and as a substitute for gravitation, which in the land
engines is used to close the balls, I make use of a spiral spring D, Fig. 6.
Thus, as seen in Fig. 6, when the balls are extended as at E, E, the plug will
close the orifice B to the utmost degree required, which is such as to counter-
act the whole of the power of the engine, even if both wheels were out of the
water, and thus the action of the engine will be regulated. I need not point
out the precise mode of connecting the governor with the moderator, because
such connexion must depend upon other arrangements, and is too well under-
stood on land engines to require further details in this.
The next point is the condensation. As sea water is found to be so destructive
to the boilers and machinery, I propose to use fresh water only for the purpose
of generating steam, and by condensing the whole of the steam that is generated,
and returning the water thus obtained without mixing the water of condensa-
tion with it, the quantity of fresh water in the boilers will always remain nearly
the same. The Figs. 7, 8, 9, 10, represent the condenser, which consists of a
combination of pipes surrounded with cold water. Any other contrivance that
would present a very extensive surface to the action of the cold water and the
steam would answer equally well, but I give the preference to this combination,
which consists, first, of an assemblage of large pipes A, Fig. 7 and 8, which
collectively form a spacious chamber, wherein the steam is let through the
pipes B', B, Fig. 7 and 4. B' is the steam pipe, and B² the waste pipe. That is,
when there is an excess of steam, instead of allowing it to escape, as is now the
case, I propose to have a safety valve connected with that pipe, by which that
excess will ender the condensors. As there is a perfect command of the power
of the engine by means of the moderater, I propose to have the paddle

page_text: wheels shafts connected or unconnected, at pleasure, by the means usually
employed, and to let the steam engine work out the steam as it happens to be
generated. The smaller pipes B, B, B, Fig. 9, which, with the large one A, A,
shew their disposition in the condensers, are so arranged so as to form indepen-
dant chambers adapted to the main one, A, and fixed to it by means of a screw
C, passing through the middle pipe. The Fig. 10 represents the manner these
small pipes are combined together, and how they are let in their respective
places. B represents the plan of a set of pipes; C, the cups into which they
are let; and D, the seat or socket of the adjustment. All these pipes being
enclosed in an iron reservoir supplied with cold water, which is continually
changed, the steam entering the pipes is condensed, and the water thus
obtained is returned into the boiler by a small pump B, Fig. 8. As it is neces-
sary that a constant supply of cold water should be applied round the pipes,
the pump of the moderator draws off the reservoir at every stroke a certain
quantity of the heated water, and thus allows of an equal proportion of cold
water to enter into it; and to remove the air that might enter the condenser,
there is an air pump B, Fig. 5, which is connected by means of a pipe with
one of the vertical chambers of the condenser, as at D, Fig. 4. In this manner
the condensation is carried on and the vacuum preserved. With respect to the
boilers, it being a desiratum that the weight of metal should be as little as
possible without reducing the necessary capacities for the water and steam,
with these objects in view, I propose the adaptation for steam rooms of one or
more room er rooms of sufficient capacity to boilers constructed in that form
which possess the greatest strength, namely, the cylindrical form, with spherical
ends, as represented in the Figs. 11, 12, 13, 14, and 15. In the middle of
the boiler, and without cutting out the metal at that place, but merely per-
forating it with small holes, I propose to raise a cylindric or other formed
steam room, the height of which is not limited, and if two or more rooms are
found necessary they may be added in the same manner. The cylindrical body
of the boiler is intended to be kept entirely full of water, and if there is but
one steam room there will be very little agitation of the water when at sea. A
steam room might be formed by means of cylindrical or any other form
chamber laid the parellel direction with the body of the boiler, but I give the
preference to the first form. It is to be observed, that with the mode of con-
densation now proposed there will be no excess of water, and if there should
be any waste the boiler cannot be affected by the reduction of one third of the
water, provided the steam pipes are made of a yielding metal, as copper. The
connection of the steam pipes as intended to be made at the end of the vertical
pipe A, Fig. 11. The Fig. 13 represents a longitudinal section of the boiler,

page_text: and Fig. 14 a section of the plan, both shewing the disposition of the fire
places and of the flues. The Fig. 15 represent a transverse section of the
boilers and flues. I further propose to adapt to the boilers two coal feeders,
with hoppers, as represented at A, A, Fig. 12. These are intended to supply
coals through several apertures B, Fig. 13. The same boilers and feeders are
seen in Fig. 2. Fig. 16 and 17 represent the coal feeder, consisting chiefly
of a cast iron cylinder A, having several cavities C, C, C, corresponding with
the apertures B, B, B, &c., Fig. 13. In the revolving action of this cylinder the
cavities carry a certain quantity of ground coals, and distributed over the fire.
The movement is intended to be communicated from the steam engine to the
spindle C, C, Fig. 2, which acts by means of endless screws on the axis of the
feeding cylinder. Fig. 18 represents a transverse section of the said cylinder
on a larger scale. The Figure 5% represents a section on a double scale of the
parts D, D, D, in the Figure 5. The Figs. 19', 192, 20, 21, 22, and 23,
represent certain details relating to the steam piston and steam cylinder.
Fig. 19' represents part of the head beam and one of the rollers that are
destined to direct the parallel movement of the piston rod between two parallel
strait edges. Fig. 192 represents the convex part of the piston. Fig. 20
represents a sectional view of the steam cylinders, with the piston and rod. A,
steam pipe; B, steam cylinder; C, convex side of the piston; D, concave side
of the same; E, E, the packing, explained in Fig. 22; F, hollow piston rod;
G, head beam; H, H, connecting rods; J, air pump rod; K, moderator pump
rod; L, L, guide rollers; M, spring supporters applied at the extremities of
the head beam. These supporters are destined to relieve the weight of the piston
in its inclined position. The Fig. 21 represents a side view of the spring
supporters. Fig. 22 represents the packing of the piston, consisting of
a combination of cotton or any suitable substance, A, and of metal, B. The
metal spring rings B operate as a metallic packing. 23 represents that part
of the piston which corresponds with Fig. 22. It is to be observed that
I do not claim those parts that are specified in the Figs. 191, 19, 20, 21, 22,
and 23, as parts of my improvements, but as necessary agents for the purpose
of rendering the action of the steam piston as free from friction and wear as
appears practicable. I have not given the dimensions of the steam passages, or
explained the nature or the action of the valves, slides, or return pumps,
because those parts do not materially differ from the same parts in other steam
engines. The blowing valves, stop cocks, &c., are not noticed. As in the navi-
gation of rivers the common mode of condensing may be preferred to the new
one which I have explained, it is necessary to shew the adaptation of a com-
mon condenser and air pump to the marine steam engine constructed on the

page_text: principle I propose. In this case the pump of the moderator has no other
function to perform but that of a regulator. The Figure 24 represents an
engine drawn on a larger scale than in the preceding Figure 1. The
action of this engine differs but little from that of the other. The
cranks, instead of being in a single piece, are made in the usual way,
because the angle exceeds a right angle so much as to require this
adaptation, and in this case the two crank pins are connected with a link
in the ordinary manner. A, A, represents the moderator, the section of
which is seen in Fig. 26. As the movement of the water is alternate, the
plug must be acted upon at both ends in the same manner, as has been
described before, and made on the principle which is represented in Fig. 31.
It will be necessary to add to the moderator a small pipe, about a quarter of an
inch bore, destined to draw in and let out a small quantity of water to com-
pensate for the piston rod, which is alternately in and out of the body of the
pump. B, B, represent the condenser (see also B, Fig. 26). C represents
one of the air pumps, both which are seen at C, C, 26. These air pumps
are intended to act as forcing pumps, and both ways, in order to render the
resistance uniform. D, pipe leading from the steam cylinder to the condensor.
E, eduction pipe. The Figure 27 represents a plan of the disposition of the
moderator (A), of the air pumps (C, C), and of the apparatus (D, D,)
destined for counteracting the weight of the piston and rod, in order to prevent
the wearing of the lower side of the piston and cylinder. Fig. 28 is a trans-
verse section of the moderator.. Fig. 29 represents a natural view of the
apparatus D, D, described in Fig. 27. As it is important to point out how
the moderator may be applied to steam engines already constructed, parti-
cularly those wherein the steam cylinder is vertical, I should propose in that
case to adopt a moderator like the one represented in Figures 24 and 25, over
the piston rod, in which case it would extend above the deck. Any competent
engineer would easily find the means of adapting an apparatus of this descrip-
tion to an engine already constructed, and of adapting the governor already
described to the shafts. It is desirous that the rotary movement of the
governor should be as two to one at least to that of the shaft. As it may be
extremely inconvenient to have the moderators above the deck, to prevent
this I should propose one on the plan represented in Figs. 30 and 31, in
which the piston rod is made hollow, and constitutes the moderator itself. The
section area of the piston rod, as represented Fig. 30, is to that of the cylinder
in the proportion of 30 to one, consequently the diminution of the power is very
inconsiderable. The rod A of this moderator is firmly fixed at B, and the piston C
of the moderator is therefore stationary. The Fig. 31 represents a section of this

page_text: piston upon a larger scale. The water or any other suitable fluid must pass
through the several apertures D, D, D, D, and the plug E is destined to
contract the orifice F. This plug is connected with a small rod G, Figs. 30
and 31. This small rod is acted upon by the governor, to which it is con-
nected at the head H. In order to facilitate the action of this plug under the
alternate pressures to which it is exposed, it has, like that represented in
Fig. 25, two small pistons J, J, fitted into corresponding chambers. The stern
is hollow. When the water is forced in the direction of the black arrows, a
small orifice through the stem allows the water to pass in the back of the lower
piston J, and thus keeps it between two equal pressures, and when the water is
forced in the direction of the red arrows produces a similar effect on the back
of the piston J, and, vice versa, the water is forced alternately from one side to
the other, opposing such resistance as the plug E may occasion by the power
of the governor.
The lower rod K is a mere compensator; its diameter
must be equal to the upper one A. It is to be observed that I lay no claim
of improvement whatever to the condensor or to the air pumps, which constitute
a part of the marine engine, Fig. 24, as my improvements in this engine are
limited to the application of the powers in the most direct way for producing
a rotary action by placing the lines of the powers nearly at right angles
with each other, to the moderator with its governor, and to boilers of the
construction and with the adaptations which I have proposed and specified.
The contracted space to which steam engines applied to navigation, particularly
in rivers, are often limited, might not very readily admit of the manner
of disposing and combining the two engines and their parts, as I have before
represented. Then, under such circumstances, I would propose their being
placed as they are represented in the Figures 32, 33, 34, 35, and 36. The
same letters correspond to the same things. The Fig. 32 represents a lateral
elevation of the engine. Fig. 33 represents its component parts-open to view.
A, A, the steam cylinders; B, B, B, B, steam passages and slide boxes; C,
air pump; D, D, condensors; E, piston rod with a moderator, represented in
Figs. 30 and 31; F, F, steam pipes; G, crank for the air pump; H, H, pipes
leading from the condensor into the air pump, with foot valves as usual; J, J,
steam slides rods; K, K, Figs. 34 and 35, the eccentrics; L, L, the main
cranks. The governor is to be connected with the paddles shafts, and made
to act upon the extremities of the small rods at N, N, Fig. 34. When the
navigation is confined to rivers, the moderator, the governor, and the mode of
condensation which I have proposed are quite unnecessary, consequently a
common piston rod is sufficient. O, O, Fig. 32, represent the outriggers,
destined to support the weight of the steam piston. These outriggers corre-

page_text: spond with the one represented in Fig. 21, and are the same purpose as
explained in the description of that Figure. My improvement in the mode of
condensing the steam may be applied to the engine in common use, but as the
adaptation of it must depend upon the construction and position of the engine,
it is impossible for me to point out the mode of adapting it under all circum-
stances. It is only necessary to state that here must be two separate pumps,
one for the water of condensation and the other for the air, as stated in
describing my method of condensation. My improvements on boilers are
likewise applicable to the engines now in common use.
In witness whereof, I, the said Marc Isambard Brunel, have hereunto
set my hand and seal, this Twenty-sixth day of December, in the year
of our Lord One thousand eight hundred and twenty-two.