IMPROVEMENTS IN KILNS OR APPARATUS FOR GENERATING HEAT
Year: 1866

page_text: LETTERS PATENT to Peter Righetti, of 12, St. Caterina dé Funari, Rome,
for the Invention of "IMPROVEMENTS IN KILNS OR APPARATUS FOR
GENERATING HEAT."
Sealed the 6th October 1866, and dated the 6th June 1866.
PROVISIONAL SPECIFICATION left by the said Peter Righetti at the
Office of the Commissioners of Patents, with his Petition, on the 6th June
1866.
I, PETER RIGHETTI, of 12, St. Caterina dé Funari, Rome, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN KILNS OR
APPARATUS FOR GENERATING HEAT," to be as follows:-
This Invention has for its object improvements in kilns or apparatus for
generating heat. For theso purposes a vertical tapering chamber is con-
structed; the chamber may be of a rectangular or other transverse section;
the larger end of the chamber is upwards and is arched over, leaving an
opening in the centre which is carried up above the arched top; at the top
of the chamber and below the arched covering are lateral passages, by which
the heat is conveyed away for use, whether to heat boilers or vessels, or for
burning of bricks, or for other purposes. It is preferred that this kiln or appa-
ratus should be constructed of brickwork and lined with fire-brick, but other
materials may be employed in its construction, so long as the materials are
such as to resist the heat to which the lining and other parts will be subjected.
In starting this kiln or apparatus a temporary grating is introduced near the

page_text: bottom, on to which a quantity of dry wood is placed, and over this wood coke
or coal, and then a quantity of lumps of limestone, then coke or other fuel,
and then lumps of limestone, so that the whole of the interior of the chamber
below the arched top is filled, and also the continuation above the arch, the
upper part of which is the feeding opening at which the interior is constantly
fed with lumps of limestone and coke or fuel in alternate layers. When the
fire has been lighted and it has reached the arch the heated products will be
conveyed away by the lateral passages below the arched top. As the fuel in
the charged apparatus becomes consumed the burned limestone will descend
and pass out at the lower end of the chamber when the temporary grating
bas been removed. It is not essential that limestone should be introduced,
but it is desirable and it is preferred that it should be used, as a product is
thereby obtained which is valuable, but lumps of fire-brick may be used in
place thereof to perform the same part of keeping the fuel, more particularly
sinall coal or coke separate to facilitate its burning in apparatus such as is
above described.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Peter Righetti in the Great Seal Patent Office on the
6th December 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PETERS
RIGHETTI, of 12, St. Caterina dé Funari, Rome, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of June, in the year of our Lord
One thousand eight hundred and sixty-six, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Peter Righetti, Her special licence that I, the said Peter Righetti,
my executors, administrators, and assigns, or such others as I, the said Peter
Righetti, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN KILNS
OR APPARATUS FOR GENERATING HEAT," upon the condition (amongst others)
that I, the said Peter Righetti, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and in what

page_text: manner the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Peter Righetti, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
This Invention has for its object improvements in kilns or apparatus for
generating heat. For these purposes a vertical tapering chamber is constructed;
the chamber may be of a rectangular or other transverse section; the larger
end of the chamber is upwards and is arched over, leaving an opening in the:
centre, which is carried up above the arched top; at the top of the chamber;
and below the arched covering are lateral passages, by which the heat is con-
veyed away for use, whether to heat boilers or vessels, or for burning of bricks,
or for other purposes. It is preferred that this kiln or apparatus should be.
constructed of brickwork and lined with fire-brick, but other materials;
may be employed in its construction, so long as the materials are such as to
resist the heat to which the lining and other parts will be subjected.
The Drawing hereunto annexed shows a kiln or heat generating apparatus
constructed in this manner.
The kiln is charged for the first time by placing on a moveable grate near,
the bottom of the kiln a layer of about 20 inches thick of dry wood, then a
layer of about 8 inches thick of large pieces of coke or coal, and afterwards;
another layer of limestone of about 24 inches thick broken up into bits of
from 4 to 20 cubic inches, then the loading is continued with alternate layers;
of pulverized combustibles, either of coke or coals and limestone, until the;
kiln is filled up to the upper funnel. Having finished this operation, set fire
to the first layer of wood, from whence the fire passing from layer to layer;
comes to the upper part of the kiln. When the fire has reached this point>
there is a flame under the vault which will run into the passages in the vault.
and introduces itself into one or more brick or lime kilns with which these.
passages are in connection, or indeed it may be employed to heat one or more
boilers of steam engines; or, in fact, the heat that comes out of the kiln may.
be applied to any other use for which heat is required, that is to say, for
heating metal, glass, or anything else. Some holes are made underneath the
vault of the kiln to observe the force of the flame within, and when.it is seen
that the interior heat is lowering the operator should discharge part of the
contents of the kiln into the lower part by taking away some of the grates,
and this discharge naturally produces the introduction of more limestone and

page_text: combustibles into the upper funnel, by which the heat is fed, the funnel is
'filled for the part discharged, and the generator is left to itself to work.
Other holes are made in the interior of the kiln itself to see the progress of
the combustion. The discharge having been made, lime and cinders are
obtained, which are separated from each other by means of a shovel formed of
bars. The price of the sale of the lime covers the expenses of the com-
bustibles, of the purchase of the limestone, of wages, and leaves a benefit, so
that the heat which is obtained and which is very considerable and very
intense is obtained quite free from any expense. The advantages which are
derived from this system are to preserve and render serviceable all the pro-
duce of the combustion (the smoke included which comes out of the mass of
combustible burnt in the kiln) and in this manner the apparatus officiates also
as a smoke consumer, it also utilizes all the heat that is contained in the
carbonic acid gas that escapes from the limestone in the burning, the heat
generated in the transformation of the carbonic acid gas from oxide of carbon,
and the combustion of the latter, and also the heat that the limestone already
burnt gives up in cooling; unless the generator be surrounded with earth it
should be built round with a thick wall which can resist the action of tho.
heat. This system must not be confounded with the one of the simple
employing the waste heat, because there is an enormous difference between
these two systems.
In Germany attempts have been made to employ the waste heat which
escapes from the top of the limestone kilns, but the most skilful theoreticians
and experience have shown the impossibility of success, because it requires
the same degree of heat to burn bricks as it does to burn limestone. In fact,
if the limestone kiln is intermittent it is not possible to burn brick by the
superfluous heat of the former, and every time the kiln gets cool in discharging
the burnt limestone the bricks placed over it cool also. If, on the contrary,
the limestone kiln is continuous, but has no vault, it must be charged from
time to time, and in that case there is always a low temperature over the kiln,
which is not certainly sufficient to burn bricks. It must also be remarked
that in the above-mentioned kiln it is not the burning of lime which forms its
principal object, for its produce is very limited comparatively to what is
obtained by the application of the heat produced by this system, and the lime-
stone is introduced into it, firstly, to separate the large and pulverized com-
bustibles; secondly, to have by that introduction all the above-mentioned
advantages. Till now the pulverized combustibles would only be employed,
but by reducing them into bricks made by the mixture either of clay or of pitch,
but the former does not give out flames, burns very badly, and developes but

page_text: little heat, the latter costs almost as much as coals. Should there be any
circumstance in which it does not answer the purpose to use limestone it
could be replaced by pieces of fire-bricks, serving to separate the pulverized
combustibles; in this last case the heat obtained would not be obtained
without cost, but the heat would cost half that obtained by coals or coke, or
still less. This very simple system is very advantageous, because it allows
the use of pulverized combustibles without any previous preparations. The
proportion between the combustibles and the limestone to feed the kiln ought
to be varied according to the nature of the combustible and the limestone,
and is soon found out by practice.
The dimensions of the kiln shown in the Drawing may even be varied, but
as for the height it is useful to make it pretty bigb, for it has to contain three
layers, that is to say, the first, below where the lime is already cooled; the
second, in the middle which is about to get cool; and the third, in com-
bustion. As for the breadth it can be regulated according to the quantity of
beat required.
When it is wanted to be used only for pulverized combustibles in dividing
them by means of pieces of fire-bricks the proportions of the generators or
bearths may be diminished to the point of making them small for domestic
use by constructing them of iron plates lined internally with (fire-bricks).
The above-mentioned kilns may be also applied to the production of a
quantity of very pure carbonic acid gas by introducing some modifications in
its management, that is to say, by preventing the fire mounting above and
preventing the carbonic acid gas being converted into oxide of carbon; this
continual source of carbonic acid gas may be rendered useful to any manu-
facture or art to which it may be wanted.
In witness whereof, I, tho said Peter Righetti, have hereunto set my
band and seal, this Twenty-seventh day of October, in the year of our
Lord Oue thousand eight hundred and sixty-six.
PETER RIGHETTI. L.s.)