IMPROVE- MENTS IN STEEL FURNACES
Year: 1873

page_text: LETTERS PATENT to George Nimmo, of Glasgow, in the County of
Lanark, North Britain, Steel Maker, for the Invention of "IMPROVE-
MENTS IN STEEL FURNACES."
Sealed the 16th December 1873, and dated the 20th June 1873.
PROVISIONAL SPECIFICATION left by the said George Nimmo at
the Office of the Commissioners of Patents, with his Petition, on
the 20th June 1873.
I, GEORGE NIMMO, of Glasgow, in the County of Lanark, North
Britain, Steel Maker, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN STEEL FURNACES," to be as follows, that is to
say:
This said Invention has reference to certain improvements in the
construction and arrangement of crucible steel furnaces, whereby they
are made more durable and productive with greater economy than
heretofore, by utilizing the escaping heat and gaseous products therefrom,.
in generating steam, all as follows:-
The nature of this Invention consists in erecting and arranging the
vertical crucible steel furnaces in sets of two, three, four, or more on

page_text: number of furnaces formed in range, each made long enough to contain
two, four, six, cight, or more crucibles, preferably two only abreast
or in the width of the furnace.
It will be understood that these furnaces might be made of other
internal shapes and sizes, as round, oval, or polygonal, and still be con-
structed in accordance with these improvements and give approximate
advantages, although the long rectangular form stated is the simplest
and the best. And it will be understood that these furnaces might be
arranged along one side only of the steam boilers when horizontal,
whether crected with one, two, or more to the set of furnaces which
might be ranged at equal distances round the steam boiler when it was
of the vertical class, while both the boilers and their furnaces might be
ranged in sets at equal distances or angles round the chimney common
to all by separate flues and dampers to cach set and a controlling damper
to cach furnace in the set, so that when desired, as for repairs or other
causes cither the intermediate sets or the intermediate furnaces might be
used at one time, or as many as would keep up the steam in the boilers,
and when too much steam is generated the same motion of the damper
or its mechanism which shuts off the hot gases from the furnace could
also open a passage for conducting them direct to the chimney.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Nimmo in the Great Seal Patent Office
on the 18th December 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
NIMMO, of Glasgow, in the County of Lanark, North Britain, Steel
Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twentieth day of June, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said George Nimmo, Her special licence that
I, the said George Nimmo, my executors, administrators, and assigns,
or such others as I, the said George Nimmo, my executors, adminis-
trators, and assigns, should at any time agree with, and no others, from

page_text: 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 STEEL FURNACES," upon
the condition (amongst others) that I, the said George Nimmo, 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 calender months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said George Nimmo, 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 in writing, reference being had to the
several Figures and reference letters on the Sheet of Drawings which I
have hereunto appended for the purpose of showing the best modes and
means I am at présent aware of for practically carrying out or
performing my said Invention, the same reference letters indicating the
same or like parts in all the Figures.
My said Invention has reference to certain improvements in the
construction and arrangement of crucible steel furnaces, whereby they
are made more durable and productive, with greater economy than
heretofore, by utilizing the escaping heat and gaseous products therefrom,
in generating steam, all as follows:-
Figure 1 of the accompanying Sheet of Drawings is a front elevation,
partly in section at one end, of a set of five new or improved steel
furnaces A, erected and ranged in a recessed wall chamber or ash-pit A¹,
below the level 1---1 of the floor of the work along one side of a
horizontal double flue steam boiler or generator a, all constructed in
accordance with and illustrative of one modification of my said Inven-
tion. Figure 2 is a transverse section of the same arrangement as
taken on the line 2. 2 in Figure 1, but to a much larger scale, to
show the details of construction more clearly, especially for the steel
furnaces A, A, one of which is shown in longitudinal section in this
Figure, and in corresponding horizontal or plan section above it in
Figure 3; while Figures 4 and 5 are respectively a front elevation and

page_text: transverse section of one of the steel furnaces A corresponding to
Figure 2.
Referring to these Figures 1 to 5, the nature, novelty, and mode of
performing my said Invention consist all as follows:-In erecting and
arranging a set of vertical crucible steel furnaces A, in this case five,
(but it may be two, three, four, or other number) along one side of a
steam boiler or generator a (but it might be on one or both sides of on
or more steam boilers), which is preferred to be of the round horizontal
double flue or Cornish form, but it might be of any of the other
ordinary constructions in use and desired, all so that the escaping hot
gaseous products of combustion from each and all of the furnaces A, A, A,
Figures 1 and 2, are admitted to and passed into and through the
heating chambers and flues b¹ of the steam boilers a on their way to
the chimney c, as indicated by the red arrows, so as to act on the greatest
possible area of heating surface of the steam boiler or boilers ranged at
the side or between the set or sets of furnaces A, A, and thus generate.
steam for driving the motive engines of the rolls steam hammers, or
other purposes requiring such within the steel works, all with and by
this escaping heat which would otherwise be lost.
The improved crucible furnaces A, A, thus ranged alongside of the
steam boiler have each their top shifting lids or covers C, C, preferably
nearly level with the floor 1---1 of the steel furnace shop, rather
above their outlet flue B, leading into the lower part of the heating.
chamber b, and flues b', 6', of the steam generator a, to be heated by the
escaping hot gases from the furnaces, each fluc being preferably
controlled by a damper B¹.
Each furnace A is of a close self contained construction formed at a
little distance apart, with an outer metal case or frame D, D¹, D",
preferably rectangular, made of side and end cast-iron plates D, D',
respectively, secured together by bolts and flanges D" at their corners,
and lined inside with thin walls of fire-brick or other suitable or
equivalent incombustible material at the upper part A², forming the
furnace chamber A above the close ashpit E, and supported upon a
flange feather D³ formed all round the inside of the plates D, D', for the
said purpose of carrying the main walls forming the sides of the
furnace A, which is further dressed or " fettled inside with a thin
layer of "fettling" A", preferably formed of fire-clay or of ground
broken crucibles or fire-brick or mixtures of these .or other equivalent
"

page_text: t
material, every morning or so, as the furnace required, and was cooled
down, which is done and provided for by these improved thin walled
furnaces with little loss of heat every evening or so, as often as the
furnaces are desired to stop working, by having simply the furnace
_bars F carried on tumbling or jointed end cross bars F¹ just below the
side feathers D³ carrying the furnace lining at the top of the close
ashpit, so that on opening the close ashpit door E in front and
pulling out the joint or supporting pins F", the bearers F', and furnace
bars F, and fire carried on them would tumble down into the ashpit E,
and out at the door E¹, so that the heat of the furnace would soon
escape and be quite cooled down by morning, all ready for fettling up
the inner lining A" and setting up furnace bars, before kindling the
furnace and starting to smelt.
Each furnace A would have an air blowing pipe G led into its close
ashpit E at G¹, regulated by an inlet valve or slide G" from the main
air pipe or duct as G², and through which the air would be forced by a
"Root's" blower, fanners, or any other ordinary equivalent air forcing
apparatus in use, the engine for which might be supplied with steam
from a steam generator a heated by the waste or escaping heat from the
furnaces A, A.
Each furnace A would preferably be made longest transversely out
from the back wall or walls 3, 31, supporting the steam boilers a,
so as to get the greatest number of furnaces A, A, formed in a range.
Each furnace A is made long enough to contain two, four, six, eight,
or more crucibles z, preferably four in a row, as shown in Figure 2, and
wide enough for two only abreast or across in the width of the furnace,
as shown in Figures 3 and 5, all in red lines, the crucibles being set
preferably on a supporting iece z¹ of fire-brick, or ends of old broken
crucibles up off the bars, so that the fire may act more perfectly on
them.
The covers of the furnaces are formed in narrow picces C, C, C, C,
preferably four, scen at Figures 2 and 5, constructed of arched or angled
fire-brick C¹, secured on a supporting iron case C", with an eye C² on
top, by which they are all removed as desired by a hook bar along the
floor 1 -1, for the removal and insertion of the crucibles. The blue
arrows indicate the direction of the air forced through the blast
pipes G³, G, G³, and supplied by the duct or branch G¹, to the ash-pit E
of each furnace A controlled by the shutting valve G".

page_text: Each furnace A is erected with sufficient space all round it which
allows persons to get round it to erect or take it down, and for the air
to cool it down when the floor plates P above are lifted, and each close
ashpit E has a door E¹ hinged in front to facilitate the cleaning, moving,
or dropping of the furnace bars F, F, and the removal of the ashes
into the open space A¹ in front, from which they can be removed at
convenient times through the floor P above, carried on the cross
beams P¹ for the purpose.
It will be understood that the furnaces A might be made of other
internal shapes and sizes than those shown and described, as round,
oval, or polygonal, and still be constructed in accordance with these
improvements and give approximate advantages, although I believe the
long rectangular form to be the simplest and the best, and have therefore
shown and described it, that is, so long as they are constructed each
separately or by itself with thin and lined "fettled" walls A³, A", and
with close ashpit E and air blast and tumbling grate bars F, F, arranged
along one or both sides of the steam boiler or boilers (as a) when
horizontal, whatever be the number of furnaces ranged in the set,
and which might be ranged at equal distances or angles round the
steam boiler, when it was of the vertical class, while two or more
boilers a, whether horizontal or vertical, with their new or improved
crucible air blast steel furnaces A, as described, might be further ranged
in a set at equal distances or angles round the chimney c, common to all,
by a separate flue and damper (as at c¹) to each boiler or set of furnaces,
and besides the controlling damper B¹ to cach furnace A, before
mentioned, so that when desired, as for repairs or other reason or cause
any furnace A might be shut off and "put down" without affecting the
others, so that the intermediate sets or the intermediate furnaces might
be used at one time, or as many as were required to keep up the steam
in the boilers,, and when too much steam was generated the same
mechanism or mechanical motion used to shut off the gases from any
furnace A by its damper B¹ can also be made to open a passage or fluc
to conduct them direct to the chimney d when the furnace A was not
desired to be put out.
Having thus described the nature of my said Invention, and the
manner of performing the same I would observe in conclusion that
what I consider novel and Original and

page_text: Invention secured to me by the herein-before in part recited Letters
Patent is,―
First. The construction and arrangement of close air blast steel
smelting furnaces and steam boilers and their flues, all substantially as
and for the purposes herein described and as shown in the accompanying
Drawings, or any mere modification thereof.
Second. The construction of close air blast furnaces for the smelting
of steel in crucibles in a portable self contained form, with thin and
coated or "fettled" walls, and dislodging or tumbling fire-grates, all
substantially in the new or improved manner and for the purposes ]
hercin described and shown in the accompanying Drawings.
Third. The arranging of the said new or improved construction of
air blast steel smelting furnaces, in sets along or around steam boilers,
so that their escaping hot products of combustion are made to heat such
boilers, all substantially in the manner and for the purposes hercin ]
described and shown in the accompanying Drawings.
In witness whereof, I, the said George Nimmo, have hereunto
set my hand and seal, this Sixteenth day of December, in the
year of our Lord, One thousand eight hundred and seventy-
three
Witness,
W. R. M. THOMSON,
Patent Agent,
Glasgow.
GEORGE NIMMO. (L.S.)