IMPROVEMENTS IN FURNACES
Year: 1859

page_text: LETTERS PATENT to John Norman, of Glasgow, in the County of Lanark
North Britain, Engineer, for the Invention of "IMPROVEMENTS IN
FURNACES."
PROVISIONAL SPECIFICATION left by the said John Norman at the
Office of the Commissioners of Patents, with his Petition, on the 10th
May 1859.
I, JOHN NORMAN, of Glasgow, in the County of Lanark, North Britain,
Engineer, do hereby declare the nature of the said Invention of "IMPROVEMENTS
IN FURNACES," to be as follows, that is to say :-
This Invention relates to certain improvements in steam boiler and other
furnaces, and has for object the prevention of smoke and the economy of fuel..
In a furnace embodying modifications of the said improvements, the bridge at
the inner or back end of the ordinary grate bars is formed with passages.
divided by vertically disposed "quarries" or slabs of fire-brick, which are
fronted with cast-iron bars forming a grate surface, by preference inclined up
and back from the ordinary grate bars. An air passage or passages admitting
air from the ash-pit communicates with the passages formed through the bridge,
and it is intended that the air entering from below shall mingle in these
passages with the gases or aerial matters entering them from above the ordinary
fire-bars. The gases or aerial matters on issuing from behind the bridge will

page_text: mingle to a greater or less extent with the gases or aerial matters passing
over the bridge, and will impinge against a second bridge formed with passages
which are inclined in various directions to induce a thorough mixing of the
gases or aerial matters. This mixing is also further promoted by a third bridge
placed immediately behind the second, and formed by preference with its top
edge slightly projecting forward, but without passages through it. The details
of these improvements may be modified in various ways. The front of the first
bridge may be made vertical, but it is preferred to incline it.
The cast-iron bars upon the face of the first bridge may in some cases be dis-
pensed with, as may also the third, or third and second bridges, whilst the position
of what has been described as the first bridge may be modified, that is to say,
the passages or spaces for the mixing of the air with a portion of the gases or
aerial matters from above the ordinary fire-bars, may be formed or arranged in
various parts of the furnace, or of the flame bed. The passage or passages for
supplying the air into the bridge may be arranged in various ways, but it is
preferred ho have a passage communicating directly with the ash-pit, and
inclined downwards, so that ashes falling into it may descend into the ash-pit.
The air supply may be adjusted by means of a door or valve at the mouth or
other part of the passage or passages.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Norman in the Great Seal Patent Office on the 10th
November 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
NORMAN, of Glasgow, in the County of Lanark, North Britain, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of May, in the year of our Lord One
thousand eight hundred and fifty-nine, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Norman, Her special licence that I, the said John
Norman, my executors, administrators, and assigns, or such others as I, the
said John Norman, 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

page_text: "IMPROVEMENTS IN FURNACES," upon the condition (amongst others) that I, the
said John Norman, 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 John Norman, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement in writing, reference being had to the accompanying Drawings, and
to the letters and figures marked thereon, that is to say:―
My said Invention relates to certain improvements in steam boiler and other
furnaces, and has for object the prevention of smoke and the economy of fuel.
And in order that the same may be properly understood and carried into
effect, I shall particularly describe two examples of furnaces embodying
modifications of my improvements, referring as I proceed, to the accompanying
Sheet of explanatory Drawings, upon which I have delineated such examples.
In the said Drawings the same reference letters mark the same or like parts
in all the Figures.
65
Figure 1 is a longitudinal vertical section; Figure 2 is a transverse vertical sec-
tion; and Figure 3 is a horizontal section, showing a furnace applied externally to
a cylindrical steam boiler. In this example, the bridge A, at the inner or back
end of the ordinary grate bars B, is formed with passages divided by vertically
disposed quarries" or slabs of fire-brick C, which are fronted with cast-iron
bars D, forming a grate surface, by preference inclined up and back from the
ordinary grate bars B. An air passage or passages E, admitting air from the
ash-pit F, and fitted, if necessary, with an adjustable damper or valve, com-
municates with the passages formed through the bridge A, and it is intended
that the air entering from below shall mingle in these passages with the gases
or aerial matters, entering them from directly above the ordinary grate bars B.
The gases or aerial matters on issuing from behind the bridge A, will mingle
to a greater or less extent with the gases or aerial matters passing over the
bridge A, and will impinge against a second bridge G, formed with passages
which are inclined in various directions to induce a thorough mixing of the
gases or aerial matters. This mixing is also further promoted by a third
bridge I, placed immediately behind the second G, and by preference formed
with its top edge projecting slightly forward, but without passages through it.
The details of these improvements may be modified in various ways. The
H,

page_text: front of the first bridge A may be made vertical, but it is preferred to incline
it as shown. The cast-iron bars D, upon the face of the first bridge A, may
in some cases be dispensed with, as may also the third, or third and second
bridges I, G, whilst the position of the passages described as formed in the first
bridge may be varied from that shown, and these passages or spaces for the
mixing of the air with a portion of the gases or aerial matters from above the
ordinary fire-bars may be formed or arranged in various parts of the furnace
or of the flame bed. The passage or passages for supplying air into the bridge
or into the first mixing passages may be arranged in various ways; but it is
preferred to have a passage E communicating directly with the ash-pit F, and
inclined downwards, as shown, so that ashes falling into it may descend into
the ash-pit. The air supply may be adjusted by means of a door or valve at
the mouth or other part of the air passage or passages E.
Figures 4, 5, and 6 are respectively a longitudinal vertical section, a transverse
vertical section, and a horizontal section, showing the mode of arranging my
improved furnace in the main flue J of a cylindrical boiler. In this example
the third bridge (marked I in Figures 1, 2, and 3,) is omitted; but in other
respects the description already given is as applicable to this as to the first
example. It will be obvious to the practical furnace builder, that the furnace
details may be modified to suit every kind of boiler, and also to meet the
requirements of other than steam boiler furnaces.
Having thus particularly described my said Invention, and the manner in
which the same is or may be used or carried into effect, I have to state that I
do not restrict myself to the precise details herein-before described or delineated,
and that I do not claim to have invented every separate detail herein-before
described and delineated; but that what I consider to be novel and original,
and claim as the Invention secured to me by the herein-before in part recited
Letters Patent, is, the constructing of furnaces with passages for mixing air
with the hotter portion of the firo gases, and with arrangements for inducing
the subsequent thorough mixing of this mixture with the remainder of the
fire gases, substantially as herein-before described.
In witness whereof, I, the said John Norman, have hereunto set my
hand and seal, this Ninth day of November, in the year of our
Lord One thousand eight hundred and fifty-nine.
JOHN NORMAN. (L.S.)