An Improved Shaft Kiln or Furnace for Burning Lime, Cement, and like Substances.
Year: 1899

page_text: Date of Application, 17th June, 1899-Accepted, 29th July, 1899
COMPLETE SPECIFICATION.
...
An Improved Shaft Kiln or Furnace for Burning Lime, Cement,
and like Substances.
I, FRIEDRICH C. W. Tм, of 16, Oberstrasse, Hanover, in the Empire of
Germany, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement ;-
The iron kilns for burning lime, cement and like materials hitherto employed.
have the drawback that the iron walls somewhat easily crack. Under suitable
circumstances and more particularly where compressed air is used, flames project
from the openings thus formed and accelerate further the destruction.
This cracking is in the first place caused by the thick and especially unequal
section of the metallic walls, because these are subjected to great expansions of
the material in consequence of differences of temperature which arise. On the
other hand in view of the necessary firmness and rigidity it is impossible to
make the walls of less than a certain thickness, as the pressure exerted by the
walls of the preliminary heater. in combination with the lateral pressure of the
fuel contained in the furnace would soon cause an alteration in the shape by
bulging out the walls contained within the zone of combustion.
By the present invention the employment of comparatively thin walls is
rendered possible without having to fear the before-mentioned difficulties.
For this object a casing is placed round the furnace shaft which is prefer-
ably constructed of several sections lying one above another or of separate rings
in such a way that the furnace walls are supported against it at numerous points
and the air contained in the interstices also prevents the action of the weather
on the working of the furnace. Such a casing may be preferably made of corru-
gated sheet metal to which a further stiffening may be given by means of rings
placed round it as shown in Figure 1 of the accompanying drawings, or a cylin-
drical casing may be arranged, from which supports of any suitable kind project
to the wall of the furnace and thereby effect its stiffening.
As shown in Figure 2 semi-tubular supports and in Fig. 3 circular supports
and in Figure 4 I-irons may be employed. Of course T, 3, Z or other irons
may be employed, and the shape of the insertion may be of any suitable kind.
If 'the separate protective action of the casing be not sought for, it is suffi-
cient to replace the casing by rings placed round the shaft which hold together
the supporting bodies.
By suitable projections or intermediate parts (springs) it may be provided
that the expansion by heat of the furnace walls does not cause any danger to
the casing.
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:-
The improvement in shaft furnaces of iron, steel or the like for burning lime,

page_text: cement and like materials consisting in providing a casing consisting of a com-
plete cylindrical surface composed of several sections lying one above the other
or consisting of separate rings against which the wall of the furnace is supported
by means of suitable supporting bodies at several places, or with intermediate
parts or springs, substantially as herein before described.
Dated in 10th day of Two 1900
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.