CERTAIN IMPROVEMENTS ON MY FORMER PATENT, BEARING DATE THE NINETEENTH DAY OF OCTOBER, 1818, FOR CERTAIN NEW METHODS OF CON- STRUCTING STEAM ENGINES
Year: 1821

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Sir WILLIAM
CONGREVE, of Cecil Street, Strand, in the County of Middlesex, Baronet,
send greeting.
WHEREAS Ilis: 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 Westminster,
the Twenty-eighth day of September, in the second year of His reign, give
and grant unto me, the said Sir William Congreve, my exors, adñiors, and
assigns, His especial licence, full power, sole privilege and authority, that I,
the said Sir William Congreve, my exors, adñiors, and assigns, during the
term of years therein mentioned, should and lawfully might make, use,
exercise, and vend, within-England; Wales, and the Town of Berwick-upon-
Tweed, my Invention of CERTAIN IMPROVEMENTS ON MY FORMER PATENT, BEARING
DATE THE NINETEENTH DAY OF OCTOBER, 1818, FOR CERTAIN NEW METHODS OF CON-
STRUCTING STEAM ENGINES;" in which said Letters Patent there is contained a
proviso that if I, the said Sir William Congreve, shall not particularly describe.
and ascertain the nature of my said Invention, and in what manner the same
is to be performed, by an instrument 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, I, the said
Sir William Congreve, do hereby declare that my said Invention is described
in manner following (that is to say):-
I work all the various constructions of rotary steam engines, as well as
those on the reciprocating principle embraced in my Patent of the Nine-
teenth October, One thousand eight hundred and eighteen, in a medium of
fluid (or melted) metal or alloy in lieu of water, as I do thereby obtain
an additional power in proportion to the increased density of the medium so
employed with an engine of the same dimensions or equal powers with engines
the magnitudes of which are reduced in those proportions; and as I do
thereby further increase the powers of those engines of given dimensions, by
causing the temperature of the surrounding medium of melted metal or alloy
to be kept higher than that of boiling water, so that the energy of the steam
may be made equal to that of any high-pressure engine, though the surface of
the medium be open to the air; while, on the other hand, by working with
the medium in a close vessel, and applying a condenser to exhaust the steam
as it rises to the surface of the medium, a still further expansion of the
steam, and consequent increase of power, may be obtained with a given
temperature and given means, by thus removing the incumbent pressure of
the atmospheric. The importance of these new principles will at once be
understood by those who are versed in these matters, as they will perceive
(taking one instance only by way of example). that by working the simple
rotary engine of my Invention, formed by the immersion of a common
hydraulic wheel, (as described in the first case in the Specification of my
above-mentioned Patent,) in a medium, the specific gravity of which to water
shall be as ten to one, a small wheel of two feet in diameter in such a medium
will he impelled by steam of the same pressure as a wheel of twenty feet
in diameter working in boiling water; and, consequently, that whereas to
obtain the same pressure as that of the steam of a common condensing engine
from steam working on this principle in a medium of boiling water, would
require a machine of very large dimensions, this same effect may be produced
in a heavier medium by a machine of very moderate dimensions indeed.
It must also be obvious that by working the steam in à medium of increased
temperature, the size of the boiler and the consumption of fuel may be con-
siderably reduced, since I find that the volume of the steam from a small
boiler is thus very rapidly increase:l, even to the extent of three or four fold,
without any extraordinary degree of heat in the medium, and that still greater
volumes may be produced by such temperatures, as may be readily obtained
from these media of melted metals or alloys; neither is there any difficulty in

page_text: In
keeping the melted metal or alloy, when once properly heated, in a perfectly
fluid state in these operations. Indeed, by carrying these principles .to a.
greater extent, the necessity of a boiler may altogether be obviated, and the
steam produced at once by the injection of small quantities of boiling water
from time to time into a small inverted receiver in the heated medium, from
whence it will be carried to the proper part of the revolving wheel or bucket,
, or other receiver, in which it is to act according to the particular construc-
tion of the engine, and in which inverted receiver the steam, from the rapidity
of its generation, must be created at a much less expence of fuel than in any
of the ordinary processes of the boiler, wherein as the generation is com-
paratively so much slower, there is consequently so much more time even for
the loss of heat by radiation. In fact, whether this heated medium operates
by increasing the volume of steam ready formed in a separate boiler, or in the
immediate generation of it without a separate boiler, the increased volume
in one case, and the entire generation in the other, are effected in the very
same moment that the steam produced is brought into action, and, con-
sequently, without allowing any interval of time for the loss of heat.
the present state of this novel and rapid mode of producing and applying
the force of steam, it is indeed impossible to say to what extent of power the
effect.may be carried in proportion to the fuel consumed; it is evident, how-
ever, that so far from any possible condensation taking place in the steam
from the time of its generation to that of its action, the tendency of this mode
of applying it is that of a continued accession of temperature. It remains
only to state that I apply these modes of generating steam, or of increasing
its volume when generated in a common boiler, to any and every description
of engine. In the first case the substitute for the boiler is a moderately-sized
strong vessel, partly filled with the melted metal. or alloy, into which small
quantities of water are injected at the required intervals, that water being
brought into a boiling state in its passage to the melted metal and before it
comes into actual contact with it; and in the last case the steam is merely
passed through such a vessel in its way from the boiler to the engine. To
regulate the heat of the fluid or melted metal, or alloy, whether it be employed
as the medium in which the power is to be obtained, or for the generation
or increase of the steam, the iron vessel in which it is heated should be
surrounded by another iron vessel or jacket, filled (where a high temperature
is desired) with oil or other such substance, by which arrangement the
maximum temperature of the metallic medium will be limited to the boiling
point of the surrounding fluid, and in this case an alloy of equal parts of tin
and lead may be conveniently used, as it is not expensive, and becomes fluid

page_text: at about three hundred degrees of Fahrenheit. Where only a low temperature
may for any particular reason be desired, the medium employed should be
that alloy commonly known by the name of fusible metal, having the vessel
in which it is melted immersed in boiling water. This medium becomes
fluid at about two hundred degrees of Fahrenheit. All the provisions of this
Patent also apply to the hydraulic wheel engines, whether the steam be made
to enter into the buckets at their circumference, or through a hollow axis,
and whether those buckets be open buckets or close ones.
In witness whereof, I, the said Sir William Congreve, have hereunto
set my hand and seal, this Twenty-eighth day of March, in the year
of our Lord One thousand eight hundred and twenty-two.
WILLIAM (L.S.) CONGREVE.
Inrolled the Twenty-eighth day of March, in the year of our Lord
One thousand eight hundred and twenty-two.