Improvements in Kilns for Burning Cement and other Minerals.
Year: 1894

page_text: Date of Application, 9th May, 1894-Accepted, 25th Aug., 1894
COMPLETE SPECIFICATION.
Improvements in Kilns for Burning Cement and other Minerals.
I, EDUARD CRAMER, Chemist, of Krupp-strasse No. 4, Berlin N.W. in the
German Empire, 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 cement kilns hitherto knowu have the inconvenience, that the cement clings
or sticks to them and must be chiselled off by means of rods. The reason for it is,
that the walls of the furnace are (owing to the radiation of heat) cooler than the
material to be burned. The viscous cement clinkers adhere to the walls, till they
are shaved off by the weight of the cement stones lying upon then, or till they are
chiselled off.
This inconvenience is prevented by giving to the walls of the furnace a higher
temperature, and this may be attained by the application of hollow bricks, through
which bricks pass the heating gases.
I obtain an equally good result by the application of rods, or ledges in the wall
or shaft of the furnace, as illustrated by the accompanying drawings, of which
Fig. 1 is a horizontal section of a furnace embodying my invention,
Fig. 2 a vertical section of the left half of the same along line A-B, and
Fig. 3 a vertical section along line B-C of Fig. 1.
The heating gases pass through the spaces between the said bars or ledges a a
and heat the same from two sides.
To
Another inconvenience is, that the softened clinkers are pressed together by the
weight of the material lying upon them, so that large solid blocks are formed,
which prevent the passage of the heating gases and hinder the draught.
prevent the contents of the furnace from pressing upon the burnt clinkers, I
provide the shaft with oblique bars or beams b, which have the form of a grate,
in order that the air may pass through the same, while the mass below the beams b
is relieved of top-pressure.
The base plate of the burning zone proper is formed of hollow plates or bricks,
through and under which pass the heating gases, so that the cement to be burned
comes to lie upon a thoroughly heated base plate. The kiln is heated by lateral
fire places, preferably gas furnaces.
g
The heating gases are produced by generators d. The gas enters directly the
combustion chamber e, into which is conducted heated air through the channel f.
The resulting flame displays its greatest heating capacity in the chamber
and is
partly used for heating the base plate c. The cement lying upon the base plate c
is thus exposed to an effective heating flame from all sides. The base plate is
inclined, as it has been found in practice that the burnt cement will slide down
upon the inclined plate c.
The cement clinkers fall over the projecting edge of the base plate a through
chamber g into the collecting chamber h. From there they are drawn through
opening into the cooling (annealing) chamber i. The air which is heated by the
clinkers in process of cooling, is conducted through the channels m np to the
combustion chamber e and is used for burning the heating gases arising from
the generators d.
The advantages of my construction are as follows:
1. The burning zone is formed of rods, ledges or bars easily heated;
2. The flame is allowed full display in a free chamber;
3. The material to be burned is exposed to the heating flame from all sides:

page_text: Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a kiln, the combination of heating rods or ledges a, with inclined beams or
bars 6 forming a grate, and a base plate c placed over a combustion chamber g,
substantially as described and for the purpose specified.
2. A cement kiln embodying or containing the improvements described above
with reference to the accompanying drawings.
Dated this 7th day of May 1894.
E. CRAMER,
By Fairfax & Wetter,
433, Strand, London, Agents.