Improvements in Annealing Furnaces
Year: 1899

page_text: Date of Application, 5th July, 1890 Accepted, 16th Sept.,
1899
COMPLIR DIPULATION,
Improvements in Annealing Furnaces,
I, HERMANN TIMMLER, Manager of Rolling Mills, of Dillingen on the Saar, in
the Empire of Germany, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and.by the following statement:-
-
The annealing furnaces hitherto employed in fine metal sheet rolling mills,
and with a fire-place at the side or underneath, all have the great disadvantage that
the annealing box standing in the annealing chamber is always irregularly
heated, in consequence of which also the annealed metal sheet produced in the
box is quite irregularly annealed and never equally soft as well as ductile. The
side of the box which lies nearest to the fire-place, is also heated more quickly
and intensely than the sides of the box lying farther away from the fire-place
and only coming into contact with the flames later. If large annealing boxes
of 2 and more metres in length be used for the purpose, two separate side fire-
Here then
places are necessary for the working of the furnace instead of one.
arises a further great disadvantage, viz: if one of these fire-place be somewhat
more largely fed by the stoker, the heating of the annealing box on this side
together with the contents is much better..
These disadvantages of an entirely irregular heating of the annealing box in
the annealing chamber it is now intended to obviate by the employment of an
upper chamber, for preliminarily distributing and mixing the heating gases,
situated above the annealing chamber, as well as by the arrangement of the flue
opening exactly in the middle of the bottom of the annealing chamber, in com-
bination with a novel annealing box constructed for the purpose, the bottom of
which is furnished with heating channels, all terminating in an opening which
in the annealing process is placed exactly in communication with the furnace
flue opening.
The new furnace however which was constructed as a first experiment at a
German iron works and is furnished with only three large upper gas outlet open-
ings in the bottom of the upper preliminary gas mixing chamber, has the great
disadvantage that the flames from the three openings come into contact very
forcibly with the annealing box beneath at three points of the box cover, so that
these places become blistered and cracked at the first annealing charge, whereby
after the charging has taken place from 3 to 5 times, the cover becomes so per-
vious that the expensive annealing box bell with cast steel cover must be replaced
by a fresh bell or cover. Finally, after several futile attempts, it has been found
possible to obviate this last disadvantage in a satisfactory manner: the three
large upper gas outlet openings are replaced by uniformly distributed small
openings in the body of the preliminary mixing chamber constructed as a grated
brickwork. By means of this grated' heating chamber arch or vault not only are
the heating gases once more thoroughly interinixed with each other, but burning
brightly and also distributed below the arch or vault they enter the annealing
chamber quite uniformly, fill the same with a single sheet of flame only
and come with their heat in contact with all parts of the box in so completely

page_text: uniform a manner that blisters and cracks no longer occur in the box and the
durability of the same is thus very considerable.
The improved annealing furnace is illustrated in the accompanying drawing,
Fig. 1, being a longitudinal section, Fig. 2 a cross-section, Fig. 3 a plan of the
same. Fig. 4 is an inverted plan of the annealing box. It consists of the separ-
ately served fire-places a a with grates or bars, on which coal is burned which pro-
duces gas in large quantity. The vaporous gases from the coal ascend through
the openings oo around the pillars with eddy like draught action and then
enter the arched upper preliminary chamber b. Here, the heating gases com-
pressed in flowing past the pillars m and the tongue or feather / spread out again,
completely fill the chamber and are thoroughly mixed together; whereby the
somewhat differently heated heating gases of both fire-places a a acquire an
exactly equal temperature. The hot heating gases uniformly intermixed, then
flow through the distributed grating like openings cc of the heating chamber
arch or vault, quite uniformly into the heating chamber d from above. In the
latter is the annealing box e that is to be heated, the double bottom k of which
is furnished, according to Fig. 4 with radially running ribs r between which are
heating channels f terminating exactly in the middle, in the heating gas out-
let which latter corresponds with the flue opening in the bottom centre of
the annealing chamber.
The heating gases entering from above through the openings c now flow around
the annealing box e with its contents on all sides uniformly and pass through
the radial channels ff of the bottom k to the outlet opening g, thence through
the flue opening into the flue i to the chimney. As the strength of the lower
wall of the annealing box above the channels f is equal to that of the bell e and
the heating gases in the middle beneath the annealing box can only escape into
the furnace flue opening h, the top, the four sides and the lower wall of the an-
nealing box are also quite uniformly heated and rendered incandescent by the
now equally hot heating flames; the fine metal sheet therein being also heated
in like manner.
By means of this entirely novel arrangement of the furnace with flue outlet
opening in the middle of the heating chamber bottom it is possible now to subject
the annealing box e with its contents uniformly to the heat of the surrounding
flame and to prepare a sheet metal product quite uniformly annealed throughout
possessing equal ductility and softness for all stamping and pressing purposes
with a much smaller consumption of coal.
In the same manner the box e becomes far more durable, owing to the heating
thereof being now uniformly effected on all 6 sides.
If the furnace be enlarged in the cross-section of the heating chamber d on
both sides by an extension such as q indicated in Fig. 3 by dots, a channel an-
nealing furnace results, which at the same time receives tliree annealing boxes;
the middle one of which below the perforated arch or vault ee stands in a simple
sheet of flame, whilst the two other boxes are preliminarily heated from the
centre, and gradually cooled again.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
A box annealing furnace in which an arch or vault furnished with uniformly
distributed perforations is arranged above the annealing chamber d, and
above which is a chamber 6 for preliminarily distributing and mixing the heating
gases and constructed as a grated brickwork, and separated by gas mixing pil-
lars m from both shafts of the fire places a a in which and by means whereof the
uniformly hot heating gases coming from the two grates or fire-places a a are
thoroughly intermixed with each other and acquire a completely uniform tem-
perature, in which condition the gases enter the annealing furnace d uniformly
through the perforations burning brightly, surrounding on all sides the

page_text: annealing box therein with its contents and are only carried off through the flue
outlet opening located exactly in the middle of the chamber bottom to the
smoke flue.
Datel this. 5th day of July 1899
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.