IMPROVEMENTS ON THE STEAM ENGINE
Year: 1829

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN UDNY,
of Arbour Terrace, Commercial Road, in the County of Middlesex, Esquire,
do send greeting.
WHEREAS His most Excellent Majesty King George the Fourth, by His
Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Fourteenth day of
January now last past, did grant unto me, the said John Udny, my executors,
administrators, and assigns, His special licence, full power, sole privilege and
authority, that I, the said John Udny, my executors, administrators, and
assigns, during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England, Wales, and the Town of Berwick-
upon-Tweed, and also in all Flis Majesty's Colonies and Plantations abroad, my
newly invented "IMPROVEMENTS ON THE STEAM ENGINE;" in which Letters
Patent there is a proviso obliging me, the said John Udny, under my
hand and seal, to cause a particular description of the nature of my said
Invention, and in what way the same is performed, to be inrolled in His
Majesty's High Court of Chancery within two calendar months next and
immediately after the date of the said recited Letters Patent, as in and by the
same (reference being thereunto had) may more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Udny, do hereby declare that my said Improvements on the Steam
Engine consist,
Firstly, in causing the same steam to act twice by means of three working
cylinders primarily with its full density throughout the stroke in two of them,
operating in each alternately, that is, one quantity of steam performing in the

page_text: one vessel in its concentrated state, and another measure producing its effect
in the second one after the other, such actions being the result of the increase
of volume in the elastic fluid from a constant formation of it (without change
of consistence or force) enlarging the vessel to accommodate itself in the only
possible direction, viz., that of the course of the piston, and again simultaneously
in like constant succession, but in a reverse rotation, making the steam which
had so priorly acted expand from these two vessels by its inherent clastic
quality into the third (with a force diminishing according to a calculable
ratio), having the whole internal surface of said first action vessels as a fixed
fulcrum or point of abutment from which to dilate, at a time when cach is
solely appropriated to that purpose, the bearing upon both sides of the pistons
of said first operating cylinders during the dilation of the steam, from their
cavity being also equal and uniform, so as to obviate reaction or back pressure
on the said pistons, and both of which powers of the steam are constantly,
regularly, and at the same time in operation on the engine, and are rendered
more effective by the existence of a vacuum on the side of both the pistons,
opposed to that on which the steam is pressing, as shall be more fully hercin-
after explained. And
Secondly, in an addition to a boiler of a steam engine which will prevent
the ill effects caused in one by the pitching of a vessel at sea, or by the motion
of a carriage, and also to render all boilers to which it is applied more safe and
less liable to be destroyed.
My first improvement in the steam engine aforesaid, by which the
steam is made to act twice, in the manner and with the advantage before
related, is effected by means of three working cylinders, as already stated,
furnished with pistons and rods as in Figure First in the Drawings in
the margin of these presents; two of these are to be considerably smaller than
the third (the proportion of which difference should be (at least) equal to
that between the density of the steam used in the first instance and the pressure
of the atmosphere, and may be much greater with advantage; thus, for
instance, if the density of the steam be twice that of the atmosphere, the two
smaller cylinders, which ought to be both of the same size) should be each
only half the dimensions of the large one at most, and may be even but an
eighth of that extent, and such comparative difference in the size of the
cylinders may be increased as the density of the steam (first used) is augmented;
thus the proportion between the two, when steam of 60 lbs. per superficial
inch is employed, may be as one to sixteen, if steam of 120 lbs., as one to thirty-
two, and so on in this progression, and may be to more than twice this amount
provided the vacuum be made perfect. Figure 1st in the Drawings in the

page_text: margin of these presents, represents these three cylinders in one of the positions
in which they may be placed. Where Numbers 1 and 2 denote the two small
or first action cylinders, and 3 the large or expansion one, 4 and 5 the
pistons of the two first, and 6 that of the second action cylinder; 7 the
pipe or tube from the boiler to the cylinder; 1 and 8 a similar pipe from the
boiler to the cylinder 2, while 9 and 10 shew the pipes or duets from the
vessels 1 and 2 to the condenser; the position of these four pipes is reversed
in the two cylinders, so that the steam flows under one piston and over the
other, thereby causing the whole three to rise and fall together; 11 shews the
tube of communication between the small cylinder 1 and the expansion one 3
opening above its piston 6, and 12 gives the pipe from the other small
vessel 2 to under the piston 6 of the said large cylinder. A pipe passes along
the side of the cylinder 1 externally, the terminations of which are shewn by
13, 13, and a similar tube, placed by the side of the cylinder 2, has its
openings or ends marked 14, 14; these two pipes or canals serve to equalize
the density and pressure of the steam on each side of the pistons 4 and 5, or
in the whole area of the cylinders 1 and 2; a tube from the bottom of the
large cylinder marked 15 and one from its top marked 16, both run to
the condenser; the piston rods of the cylinders 1 and 2 are marked
18 and 19, and that of the large one is denoted by 20, and a bar or
transverse piece which connects the three piston rods is marked 17, and
the valve boxes are represented by V, V, V, V. The condenser, with
its air pump, the engine beam, and the frame by which it is supported, the
connecting rods, boiler, the apparatus for working the valves, pumps, and other
gear, the fly wheel, governor, and some other less important parts, are so
similar to those used for the same purposes in other engines as not to require
a particular description, and are not represented in this Figure, and they may
be made of any proper material, and constructed and arranged without diffi-
culty by any sufficiently qualified engine maker. I have given the preference
to cylinders for this machine for the same reason which causes them to be
universally used in other steam engines, but wish it to be understood that
vessels of any form may be employed, provided they be equally fit for the
operation of pistous, and the terms above, below, top, bottom, or otherwise,
when heretofore used, and in all time hereafter, are to be regarded but as re-
lative, and not implying that it is absolutely necessary to place the machine or
its parts in any definite position, except when otherwise particularly directed.
In order to understand the manner in which this steam engine operates, let it
be imagined that, for example, the three pistons are to be made to ascend, then
the pipe 7 from the boiler to the bottom of the cylinder 1, and that marked 9

page_text: from its top to the condenser should be opened by a proper disposition of their
valves, and at the same time the tube 14, which forms a communication be-
tween the top of the cylinder 2 and its bottom, should be also opened, and
likewise the tube 12, which passes from this latter cylinder to the lower end of
the great or expansion cylinder 3, and the tube 16, which goes from the top
of the said great cylinder to the condenser, should be both opened, and while
the pipes particularized are thus opened, the apparatus that works the valves
is to be also at the same time so managed as to close the tubes marked 8, 10,
11, 13, and 15, before explained. On the contrary, when the three pistons
are required to descend, then the pipes last named, 8, by which steam flows
from the boiler to above the piston 5, of the cylinder 2, that 10, by which a
vacuum is produced beneath it, 13, by which steam passes from below to above
the piston 4 of the cylinder 1 and 11, by which the same dense steam farther
expands to above the piston 6, of the cylinder 3 and 15, by which a vacuous
state is produced under said piston, are to be opened, while simultaneously 7,
9, 12, 14, and 16, already before explained, will be closed. In the case first
described, when the pistons are to be made to ascend, on the valves being so
disposed as to open the proper set of tubes, and to shut those the actions of
which alternate with or act contrary to them, the pressure of the steam from
the boiler will operate regularly throughout the stroke with its full density by
the pipe 7 on the under surface of the piston 4, while there will be a vacuum
above it, and of course it will be sent up to the top of the cylinder with the
whole energy of the elastic fluid, and at same time the dense steam, which had
before acted in depressing the piston 5 in the cylinder 2, will pass by the
pipe 14 to below it (5), making equal strain on both its surfaces, and offering
no opposition to its being carried to the top of its cylinder by the action
of the steam on the two other pistons, and said dense steam will farther
dilate along the pipe 12 to under the great piston I, which it will raise with a
force multiplied by the excess of the area of the large cylinder over that of
the small one at first, and ultimately with a pressure more or less diminished
according to the comparative size of the cylinders and the perfection of the
condensation, which condensation results from at the same time, the pipe 16
being open from above the before-named piston 6 to the vessel in which the
steam is destroyed or reformed into water, the dilatation of the steam first
alluded to from the cylinder 2 into that 3 as a second effective power, takes
place from the whole internal surface of the first-named vessel 2, which serves
as a fixed point of abutment or back pressure for it. In the second case,
when the pistons are to be made to descend, the valves being disposed as
required for the occasion, and as before related, then, in like manner, the

page_text: steam from the boiler, acting through 8, on the upper face of the piston 5,
while there is a vacuum below it will press it down, and that which had just
operated in elevating the piston 4, will pass from below to above said piston
pressing uniformly on both its surfaces and (accommodating itself as freely to
the change of capacity in the spaces on each side of the piston 4 aforesaid, as
the dimensions of the pipe leading from one end of the cylinder to the other
will permit of) will not prevent the piston 4 from being carried without
resistance to the bottom of its cylinder by the power of tho steam on the two
other pistons, and the said dense steam will further expand out of the cylinder
1, by the tube 11, on the superior face of the piston 6, below which (the
pipe 15 being open to the condenser) a vacuum will be produced and main-
tained, and it will force down the said piston 6 with a power as before calcu-
lated in the up-stroke, the said dilating steam having the walls of the
cavity of the cylinder 1 as a fulcrum or point of resistance as the other had
those of the cylinder 2 in the last stroke, as already explained. It will be
observed on the preceding account of the engine that the steam is continually
passing into one or other of the two small cylinders, and from them again
into the large cylinder in rotation, that it operates first in raising the piston
of the small cylinder and then in depressing that of the large one, or vice
versa, and that it never reacts or counterpresses on the pistons of the small
cylinders while it is dilating from them, one of which pistons is returning to
the point of action when the steam is operating on the other, and it will be
seen at once how the operations of the engine may be continued ad libitum.
Several variations may be adopted in this engine consistently with the prin-
ciples which I have explained:-
Firstly, the size of the two small cylinders may bear several different
proportions to that of the large one, as before noticed.
Secondly, the shape of these vessels may be made to assume various differences,
with the precautions before stated.
Thirdly, the relative position of the cylinders to each other may be changed
from that represented in the first Figure, the situation of the pipes and other
parts being varied accordingly; thus (as in Figure 2), the large and one small
cylinder may be placed under one end of a beam and the other small one
under the opposite end, the steam being admitted to the bottom of each
small vessel, and the vacuum being effected above their pistons, or all the
cylinders may be at one end of the beam, one small one being above the other
so that the same piston rod will do for both small vessels passing through the
upper to the lower one, or the two small cylinders may be placed at one end of
the beam, and the large at the other, and so forth.

page_text: Fourthly, the general position of all the cylinders may be changed from
that which is vertical, and which I think the best, to one which is horizontal
or inclined in various degrees, the shape, &c., of the parts of the engine being
altered consistently.
Fifthly, the engine may be wrought with the common condenser, or, as I
would advise, for various obviously beneficial reasons, with two condensers
acting alternately, one being connected by the eduction pipe to the small
cylinder 1 and the space above the piston 6 in the cylinder 3, and the other to
the cylinder 2 and the space under said piston 6.
Sixthly, it may be wrought by high pressure steam without any condensers,
the steam after it has operated on the expansion piston being driven off into
the air by what are now the eduction pipes or ducts, to the steam destroyers.
Seventhly, the number of cylinders may be increased beyond three, which I
consider enough to answer the ends I gain.
And lastly, the tubes marked 13 and 14 may be superseded and consequently
omitted, by making adequate perforations through the two small pistons and
furnishing them with valves to which levers are to be attached, which levers will
project from the pistons, so that they shall come in contact with the inner sur-
face of the extremities of the cylinders, when the pistons approach them and open
and shut these valves, thereby in one case allowing the dense steam which
had acted on the piston to go through the aperture and equalize the density
and pressure in both chambers of the cylinder, and in the other instance
making a solid surface for the steam to operate on this will be still farther
elucidated by Figure 2, in which A denotes one small or first action cylinder
and B the other, while C shews the great cylinder; 7 is the pipe from the boiler
to A, and 8 that from said boiler to B; 9 and 10 are tubes from A and B to
the condenser; 4, 5, and 6, are the three pistons with their rods, and 1 and 2
are the openings in the pistons 4 and 5, with their valves, &c.; the other parts
are like the same ones in the other engine. The piston 4 having come to the
bottom of the cylinder A, the projecting handle of the valve 1 will touch and
shut the valve, while at the same time the upper handle will be thrown out
from the surface of the piston, the steam will then act on the piston to elevate
it at the time that this occurred; here the upper handle of the valve 2 would
also touch and open it, throwing the opposite lever out from the under
surface of the piston 5, and the steam which existed dense beneath
the piston would flow to above it and then into the cylinder 3, and thus
the actions will be carried on reciprocally as long as wished.
The pipes
9 and 16 to the condenser, or the air from above the pistons 4 and 6
in the first Figure, and those 10 and 15 from below said piston 6, and that 5

page_text: to the same destination, may be joined in pairs and farther connected so that
the valve which closes one pair will open those the action of which is con-
trary to them; 18 and 11 may also be joined, and 12 and 14, and one valve
be appropriated to all in the manner last told, and the two pipes from the
boiler may be so united that one valve will also do for both. This engine is to
be set in motion, stopped, or have its actions moderated or reversed by tho
incans usually employed in other engines.
My second improvement on the steam engine consists of an addition to the
boiler by which the ill effects are prevented to which boilers are liable when
used at sea or in a carriage from the motion, and which will render all boilers
more safe to which it is applied, and less likely to be essentially deranged.
It consists of a pipe or tubes running from the upper part of one end or side
of the boiler over its top, or along it laterally to the opposite point at or about
the same height as represented in Figure 3, where the position of one of such
pipes is given at 1, 1; through this pipe or ducts the steam, if from any cause
compressed in one part of the boiler, will find its way to another, so as to ren-
der the action in all parts of the cavity regular and uniform, and to prevent a
jet of the elastic fluid from being thrown off by the safety valve from the
agitation of the water in the boiler, in consequence of the pitching or rolling
or lurching of a vessel or carriage, by which great waste is occasioned. These
pipes may be made of copper or other material thought best, and should be
so much weaker than the boiler itself, that in the event of too great a pressure
that may burst first, and thus prevent the destruction of that essential part
and the mischief likely to arise from it; they are also to have a cock at each
end, so that should one of them give way (on these cocks at the extremities
being closed) the steam will be confined in the boiler, which will be as good as
ever, and by keeping one or more of the pipes as a reserve, from which the
steam is excluded in the first instance, and into which it will be admitted
should an accident occur to the first set, the boiler will have all the advan-
tages it possessed it first.
My claims to the before recited and described improvements on the steam
engine do not relate to every particular part of the various kinds of apparatus
that I have mentioned, several of which parts must be common to many other
engines, but are confined to the principles that I have suggested and cluci-
dated, and the new and peculiar combinations I have employed and set forth
to effect the purposes I have pointed out, and the ends I have gained and
arrived at; and, first, I claim as my Invention my first recited improvement
on the steam engine, by which the same steam is made to act twice by
means of three working cylinders, which number I am the first to employ

page_text: in this manner and with the like intention, as fully set forth as herein-
before; but be it understood I do not claim as my Invention the making
the steam to operate twice, once with its full density, as it is formed, and
again expansively, but for obtaining such double effect as I have explained,
constantly and regularly so as to give the two powers of the steam to the
engine, at the same time unremittingly, unvaryingly, and unceasingly, and
without (in the second part of the operation of the elastic fluid) occasioning
reaction or back pressure on the pistons of the first action cylinders, as in all
attempts to effect the purposes attained to heretofore, and both powers of the
steam being rendered more effective by the co-operation of a vacuum in each
instance never before accomplished.
Secondly, I claim my second recited improvement on the steam engine, in
the addition of pipes to a boiler in the manner described, so as to prevent the
accidents which may be caused by the agitation of the contents from motion to
render it less liable to burst, and not so likely to do any serious mischief should
one or more of the pipes give way, and in the last case to cause it to be still
effective, as fully set forth in my foregoing explanations and descriptions.
In witness whereof, I, the said John Udny, have hereunto set my hand
and seal, this Eleventh day of March, in the year of our Lord One
thousand eight hundred and twenty-nine