IMPROVED MANU- FACTURE OF GAS FOR HEATING PURPOSES
Year: 1874

page_text: LETTERS PATENT to Sir Francis Charles Knowles, Baronet, of Lovells
Hill, in the County of Berks, for the Invention of "IMPROVED MANU-
FACTURE OF GAS FOR HEATING PURPOSES."
Sealed the 30th October 1874, and dated the 2nd May 1874.
PROVISIONAL SPECIFICATION left by the said Sir Francis Charles.
Knowles at the Office of the Commissioners of Patents, with his
Petition, on the 2nd May 1874.
I, Sir FRANCIS CHARLES KNOWLES, Baronet, of Lovells Hill, in the.
County of Berks, do hereby declare the nature of the said Invention
for "IMPROVED MANUFACTURE OF GAS FOR HEATING PURPOSES," to be as
follows:-
My Invention relates to the generation of pure or nearly pure carbonio
oxide which I effect by the following processes
gas,
:-
The first, in which I obtain pure carbonic oxide by calcining limestone
or chalk, and thus converting into carbonic oxide the carbonic acid gas
evolved. This gas can be used alone or in mixture for general heating
purposes.

page_text: In my second method I reduce to powder the black oxide of
manganese (called "wad") and the fuel, namely, charcoal of wood or
of peat, coke, or anthracite coal, and having well mixed them in such a
proportion as to have the carbon to the free oxygen as nearly as may be
in the ratio of 6 to 8, I expose the mixture in close retorts to a strong
red heat. Carbonic oxide gas is evolved which is to be led into suitable
gasometers. When the retorts are discharged the residual mixture is at
once to be thrown into water while hot in order that the manganese
may again take up the oxygen which it has lost. It may thus be used
over and over again with little waste and cost of material.
My third method yields a gas composed of about 75 per cent. of
carbonic oxide and 25 per cent. of nitrogen. The fuel (charcoal, coke,
or anthracite coal) having been reduced to powder as before is well
mixed with pulverized nitrate of soda, previously dried, with which it
forms a kind of meal gunpowder though not itself explosive. Upon
raising this mixture to a low red heat in retorts it deflagrates and
evolves a mixture of nitrogen, carbonic acid gas, and carbonic oxide.
The carbonic acid gas unites with the soda of the nitre to form a
carbonate. The carbonic oxide and the nitrogen in the proportion of
about 75 to 25 are set free, and may be collected as usual. It is well to
let the fuel be a little in excess of the exact chemical proportion in order
to ensure the absence of carbonic acid gas; as an intense heat is evolved
this is easily done. The residue carbonate of soda is very valuable and
more than pays the whole cost of the process. It is free from sulphates
and sulphurets, and after lixiviation to free it from any coally matter
and evaporation to dryness yields a very pure carbonate of soda.
The proportion of pure carbon to the dried nitre is chemically about
one-fourth of its weight, so that according to the nature and composition
of the fuel the proportion of the fuel to the nitre is readily determined.
This suffices to saturate the soda with carbonic acid and to furnish the
75 per cent. of carbonic oxide in the gas evolved.
The above gases when burned give out a very intense heat, and they
may be easily applied for that purpose either in domestic use or in any
kind of manufacturing operation, or of metallurgy.
As it may be objected to the use of these gases for domestic purposes
that they have no odour and cannot be detected by smell when they
accidentally escape I prefer by way of prevention against danger to use

page_text: .
with them a mixture of peat gas, which when obtained from peat is
itself a gas of high heating power. About 10 to 20 per cent. of peat
gas will have the effect of giving to the compound an empyreumatic
odour, not unpleasant, but such as t render its esc ape very perceptible;
I do not however limit myself to that proportion as less may suffice. In
such a mixture the above gases may be safely distributed for heating
purposes as other gas is at present for lighting.
I also prepare a gas containing about 60 per cent. by weight of
carbonic oxide and 40 per cent. of nitrogen gas by putting in a closed
cupola alternate layers of limestone or chalk and coke, anthracite coal,
or charcoal, and keeping up the combustion of such fuel by means of a
fan blast, so regulated that no carbonic acid should be evolved from the
upper part of the cupola, the calcined lime being from time to time
discharged below by a revolving cylinder with an aperture in the side.
The proportions of anthracite would be about 3rd the weight of the
limestone or chalk, and of coke in proportion according to its richness
in carbon.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Sir Francis Charles Knowles in the Great Seal
Patent Office on the 2nd November 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Sir FRANCIS
CHARLES KNOWLES, Baronet, of Lovells Hill, in the County of Berks,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent bearing date the Second day of May, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Francis Charles Knowles, Her special
licence that I, the said Francis Charles Knowles, my executors, admini-
strators, and assigns, or such others as I, the said Francis Charles
Knowles, 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, usé, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention

page_text: Ior IMPROVED MANUFACTURE OF GAS FOR HEATING PURPOSES, upon the con-
dition (amongst others) that I, the said Francis Charles Knowles, 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 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 Francis Charles Knowles, do hereby
declare the nature of my 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 :—
My Invention relates to the generation of pure or nearly pure carbonic
oxide gas, which I effect by the following processes :—
In the first I obtain pure carbonic oxide by calcining limestone or 1
chalk, and then converting into carbonic oxide the carbonic acid gas
evolved. This gas can be used alone or in mixture for general heating
purposes.
In my second method I reduce to powder the black oxide of
manganese (called "wad") and the fuel, namely, charcoal of wood or a
of peat, coke, or anthracite coal, and having well mixed them in such a
proportion as to have the carbon to the free oxygen as nearly as may be
in the ratio of 6 to 8, I expose the mixture in close retorts to a strong
red heat. Carbonic oxide gas is evolved which is to be led into suitable
gasometers. When the retorts are discharged the residual mixture is at
once to be thrown into water while hot in order that the manganese
may again take up the oxygen which it has lost. It may thus be used
over and over again with little waste and cost of material.
My third method yields a gas composed of about 75 per cent. of
carbonic oxide and 25 per cent. of nitrogen. The fuel (charcoal, coke,
or anthracite coal) having been reduced to powder as before is well
mixed with pulverized nitrate of soda, previously dried, with which it
forms a kind of meal gunpowder though not itself explosive. Upon
raising this mixture to a low red heat in retorts it deflagrates and
evolves a mixture of nitrogen, carbonic acid gas, and carbonic oxide. 3
The carbonic acid gas unites with the soda of the nitre to form a

page_text: carbonate. The carbonic oxide and the nitrogen in the proportion of
about 75 to 25 are set free, and may be collected as usual. It is well to
let the fuel be a little in excess of the exact chemical proportion in
order to ensure the absence of carbonic acid gas; as an intense heat is
evolved this is easily done. The residue carbonate of soda is very
valuable and more than pays the whole cost of the process. It is freo
from sulphates and sulphurets, and after lixiviation to free it from any
coally matter and evaporation to dryness yields a very pure carbonate of
soda.
The proportion of pure carbon to the dried nitre is chemically about
one-fourth of its weight, so that according to the nature and composition
of the fuel the proportion of the fuel to the nitre is readily determined.
This suffices to saturate the soda with carbonic acid and to furnish the
75 per cent. of carbonic oxide in the gas evolved.
The above gases when burned give out a very intense heat, and they
may be easily applied for that purpose either in domestic use or in any
kind of manufacturing operation, or of metallurgy.
As it may be objected to the use of these gases for domestic purposes
that they have no odour and cannot be detected by smell when they
accidentally escape, I prefer by way of precaution against danger to use
them in a mixture with them of peat gas, which obtained from peat is
itself a gas of high heating power. About 10 to 20 per cent. of peat gas
will liave the effect of giving to the compound an empyreumatic odour,
not unpleasant, such as to render its escape very perceptible; I do not
however limit myself to that proportion as less may suffice. In such a
mixture then the above gases may be safely distributed for heating
purposes as other gas is at present for lighting.
I also prepare a gas containing about 60 per cent. by weight of carbonic
oxide and 40 per cent. of nitrogen gas by putting in a closed cupola
alternate layers of limestone or chalk and coke, anthracite coal, or char-
coal, and keeping up the combustion of such fuel by means of a fan
blast, so regulated that no carbonic acid should be evolved from the
upper part of the cupola, the calcined lime being from time to time
discharged below by a revolving cylinder with an aperture in the side.
The proportions of anthracite would be about 1/3rd the weight of the
limestone or chalk, and if coke in proportion according to its richness
in carbon.

page_text: And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim,—
Firstly. The manufacture or generation of gases composed of carbonic
oxide, wholly or in part; such carbonic oxide being generated in retorts
by means of pulverized charcoal, coke, or anthracite coal, mixed with
(a) pulverized black oxide of manganese, (b) nitrate of soda, dried and
pulverized as and for the purposes set forth.
Secondly. The generation and employment of carbonic oxide gas made
from limestone or chalk, as described above, either pure or mixed with
nitrogen.
Thirdly. I also claim the collection of all or any of such before
mentioned preparations of carbonic oxide gas, its mixture with gas
made from the peat referred to in the Specification of my Patent No.
1547, dated 1 May 1874, and the distribution of such mixture to the
public for heating purposes.
Fourthly. The use of carbonic oxide gas, made in a cupola as above
described, and composed of about 40 per cent. of nitrogen and 60 per
cent. of carbonic oxide gas, for the purposes of heating steam boilers or
melting metals, or heating retorts by appropriate furnaces, or for
general heating purposes, when mixed with a small proportion of peat
gas, as set forth.
In witness whereof, I, the said Francis Charles Knowles, have here-
unto set my hand and seal, this Second day of November One
thousand eight hundred and seventy-four.
גד
2
YT TAGדמזגז