AN IMPROVED STEAM ENGINE
Year: 1824

page_text: HALL'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL HALL,
of Basford, in the County of Nottingham, Cotton Manufacturer, send greeting.
WHEREAS His most Excellent Majesty King George the Fourth, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Eighth day of April, in the fifth year of His reign, did, for
Himself, His heirs and successors, give and grant unto me, the said Samuel
Hall, His special licence that I, the said Samuel Hall, my exors, adñiors,
and assigns, or my or their servants or agents, or such others as I, the
Samuel Hall, my exors, adñiors, and assigns, should at any time agree with,
and no others, from time to time and at all times during the term of fourteen
years from the date of the said Letters Patent next ensuing, should and
lawfully might make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, and also in all His Majesty's Colonies and
Plantations abroad, my Invention of "AN IMPROVED STEAM ENGINE;" in which
said Letters Patent there is contained a proviso obliging me, the said Samuel
Hall, by an instrument in writing under my hand and seal, particularly
to describe and ascertain the nature of my said Invention, and in what
manner the same is to be performed, and to 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 in part recited Letters Patent, reference
being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Samuel Hall, do hereby declare that the nature of my said Invention, and the
manner in which the same is to be performed, is described and ascertained in
and by the Drawing hereunto annexed, and the following description thereof
(that is to say):-

page_text: The object of my Invention is to diminish the quantity of fuel required at
present in working steam engines, even of the best construction, and thereby
to enable those persons who employ steam engines to produce the power
required by them at less expence. My method of effecting this is by decom-
posing the steam more or less completely in its passage from the boiler to the
working cylinder under a pressure superior to that of the atmosphere. The gases
or elastic fluids thus generated occupy a greater space at any given pressure and
temperature than the steam does by means of which they are produced, and
being for the most part permanently elastic fluids they possess the additional
advantage of being capable of use at a temperature not higher than that of the
atmosphere, if required. In order to accomplish the above-mentioned object, I
employ the apparatus which is described in the annexed Drawing. R, R, R, R,
Figs. 1, 2, 3, and 4, is a hollow cylinder or vessel of cast iron or other suitable
material, which vessel I call the furnace. It is placed in a vertical position
when in use, and is so closed as its lowest extremity, by a plate V, Figs. 2, 3,
and 4, as to be perfectly air tight, except by the orifices herein-after described.
Two of these, namely, one in the top and another in the bottom, as shewn at
Y and Z, Figure 4, are commanded by large stop-cocks, as at J, C, and I, b,
in Figs. 2, 3, and 4, or by valves or other contrivances, by which the vessel
R, R, R, R, may be opened and shut in an air-tight manner at pleasure. This
vessel is to contain the fuel, which is supplied through the upper stop-cock I b,
Figs. 2, 3, and 4, and rests upon a grating of a double hopper form, shewn in
section in its proper place at L, Fig. 4, and in a detached state by the perspec-
tive view of the same at Fig. 5. The lower stop-cock J, C, Figs. 2, 3, and 4,
is for the purpose of removing the ashes and clinkers of the fire, and never
requires to be opened except for this purpose. Another opening O, Figs. 2, 3,
and 4, is connected by the pipes N, N, and M, Figs. 1, 2, and 3, with a
bellows or other blowing machinery, by which a strong current of atmospheric
air can be passed through the ignited fuel contained in the interior space H,
Fig. 4, of the furnace, whenever its upper stop-cock I, b, is open, and the blast
of air may at any time be shut off by the cock e, in the pipe N, Figs. 1, 2, 3,
and 4. The furnace cylinder or vessel is surrounded by another exterior
cylinder or casing of cast iron or other sufficiently strong material, which I call
the boiler, as shewn in section at D, D, Fig. 4, in such manner as to leave a
space G, G, all round the furnace, which space is to be nearly filled with the
water to be converted into steam, and on this account all its joints must be
perfectly air-tight. A strong steam pipe K, Figs. 1, 2, 3, and 4, furnished with
a stop-cock as at d, communicates with the upper part of the boiler space G,
Fig. 4, and descending, opens into the lower end of the furnace cylinder at X,
about the central part of the hopper-shaped grating L, so that on opening the

page_text: per-
cock or valve d the steam that is in the boiler space G will pass through the
fuel contained in the space H, and be for the most part decomposed into
manently elastic gases, which will, with any undecomposed vapour, pass through
the orifice W, in the upper part of the furnace. To the orifice W, last
5 mentioned, a pipe P, Figs. 1, 3, and 4, furnished with a stop-cock f, Figs. 1
and 3, is attached, and this pipe conveys the permanently elastic gases and
vapour so produced into the air-tight vapour reservoir Q, Figs. 1 and 3, which
should be furnished with a safety valve as at g, and from this reservoir
they are supplied by a cock or valve, as at R, to work the ordinary
piston of a steam engine cylinder, or in any other way in which such
elastic gases or vapour can be advantageously used in the manner of
steam engines to produce motive power. In order to supply the boiler with
water, and replenish its waste by evaporation, I use a strong cylinder or
vessel B, Figs. 1 and 2, which I call the water cistern; this vessel must be
perfectly air-tight; it receives its supply of water by the cock C; from the upper
and lower parts of the water cistern two strong open pipes, E and F, proceed
in an horizontal direction, and open into the upper and lower parts of the boiler
space G, Figs. 1 and 4, so that the water in that space will always stand at the
same level as it does in the water cistern. The water cistern B is to be
replenished with water when necessary at its cock C, by means of a forcing
pump, and it has a safety valve at a. In the above description, for the sake of
simplicity, only one boiler and furnace cylinder has been spoken of; but, for the
reasons herein-after stated, it will be necessary to have at least two of them,
that they may work alternately, and thus maintain a continuous supply of
elastic gases or vapour; but one water cistern and one vapour reservoir will
be sufficient to act in common for two or more furnaces and boilers; and the
Figures 2 and 3 will shew the arrangement which I propose and recommend
for two of them, and which is made still clearer by the plan or bird's-eye view
at Fig. 1, in which the disposition of the several parts with respect to each
other is distinctly shewn, A, A, A, A, being a cast-iron frame or foundation
plate on which the entire apparatus is built or constructed, and this plate may
stand on legs or pillars or be otherwise supported at pleasure; a curved pipe
is also shewn at S, by which the water cistern and vapour reservoir may be
occasionally connected by opening a cock at h. In order to put in action the
above-described apparatus, I first fill the cistern B with water nearly up to the
pipes E,E, but the water must never be so high by at least three inches as to
un into these pipes, which circumstance may be guarded against by the means
n ordinary use for such. purposes, and which are well known. The water

page_text: flows by means of the lower lateral pipes F, F, above mentioned, into each
boiler; then (supposing all the stop-cocks to have been closed after the boilers
have been charged) I open the upper large cocks of both the furnaces, and
through them introduce red hot cokes, charcoal, or convenient fuel; next
I open the stop-cocks e, e, on the blast pipes, and by means of the bellows or
other blowing machinery cause a full stream of air to pass through the
furnaces (supplying fuel from time to time as it is wanted) till the furnaces
become full of red hot fuel, and the water in the boilers which surround them
has produced steam of the requisite degree of elasticity, as will be shewn by
the safety valve a, or by an ordinary high-pressure steam gauge, which should
be applied to some convenient part of the apparatus. The elasticity and tem-
perature of the steam which will be found the most advantageous can only be
ascertained by experience; but I believe the higher the temperature that can
be adopted with convenience and safety the more advantageous it will be.
During this time the water cistern and the vapour reservoir are to be con-
nected together by opening the cock h in the pipe S, Figs. 1 and 3, so that
the latter may be filled with steam of the same temperature and pressure
as that contained in the boilers and water cistern. Having thus produced
steam ready for work, I shut the above cock h so as to cut off the said con-
nection, and then close the cock I, b, at the top of one of the furnaces, and
likewise the cock e of the blast pipe conducting into that furnace, and I open
those of the steam pipe K and of the pipe P, which connects the furnace
with the vapour reservoir; the steam immediately passes into the furnace below
the grate L, and in ascending through the fuel, which is under the same
pressure as the steam, the latter is for the most part decomposed; the elastic
fluids which are the result of this decomposition pass out of the furnace into
the vapour reservoir, and from thence into the working cylinder of the engine,
in order to produce motive power. After a time (the length of which bears
some proportion to the pressure at which the apparatus is working, and the
magnitude of the fire and quality of the fucl employed,) the fuel in the
furnace will be so far cooled or reduced as no longer efficaciously to decom-
pose the steam, and in that case the cock on the steam pipe K, and that on
the pipe P which leads into the vapour reservoir, are to be closed, and the
cock on the top of the furnace, and afterwards that on the blast pipe N, are to
be opened, when the fuel (fresh fuel baving been added, if necessary,) will be
again supplied with air by the bellows or blowing machinery, and having
become again sufficiently heated the process already described is to be re-
peated. During the preparation for so repeating the operation of decompo-
sition the other furance is to be working in the same manner. Thus it is
obvious that when, the blast. is turned off. from one of the furnaces it is to be

page_text: turned on to the other, so that the fuel in this latter will have got up to the
working state by the time that the fuel in the former, being cooled down
below the working state, requires again the action of the blast, or being reduced
in quantity requires replenishing. By this arrangement a constant supply of
elastic fluids from the furnaces in succession is secured. For the reasons above
mentioned, the precise periods of alternating the action or operation of the
furnaces cannot be here stated, but will be readily found on using the apparatus.
The ashes, slag, and clinkers are to be got out by means of proper iron bars
introduced up the lower cocks of the furnaces, after which these cocks are to
be closed, and whenever fresh fluid is required is to be supplied through the
upper cocks as before mentioned.
The apparatus above described appears to me to be the best calculated to
answer its intended purpose. And although I do not claim the parts of the
apparatus taken separately, yet I do claim the exclusive use of them when
combined or connected together for the purposes above described. The prin-
ciple being once pointed out as above, of obtaining mechanical power by means
of the decomposition of steam, many modifications of apparatus for this
purpose will present themselves to the mind of a mechanic. Of all such, how-
ever, as depend upon the application of the same mechanical and chemical
principles as those applied by me, and described in the foregoing part of this
Specification, I claim the exclusive use.
In witness whereof, I, the said Samuel Hall, have hereunto set my hand
and seal, the Eighth day of October, in the year of our Lord One