An Improved Method. and Apparatus for the Continuous Working of Annular and the like Kilns for Bricks, Tiles, and the like.
Year: 1894

page_text: Date of Application, 28th June, 1894-Accepted, 23rd Mar., 1895
An Improved Method. and Apparatus for the Continuous Working of
Annular and the like Kilns for Bricks, Tiles, and the like.
A communication by FRIEDRICH SCHOFER, of Waiblingen, Wurtemberg, in the
Empire of Germany, Brick Works Manager.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster, and 323, High Holborn, in the
County of Middlesex, Civil 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:―
This invention has for its object mainly to thoroughly utilise the fuel in blast
drying in as complete a manner as in the ordinary annular kilns, that is to say, to
carry on the operation continuously, whilst hitherto the burning chambers were
each heated separately and the hot gases from each chamber escaped direct at a
high temperature into the chimney. Further its object is to obtain a more even
temperature in the kiln, so that its power of carrying off the evaporated moisture
from each brick is equal. An even colour in the finished product is thus obtained,
for which also an even supply or feed of the damping material is necessary. All
fire doors and passages must also be capable of being closed so as to be gas tight
in order that no air may enter, and, finally, as rapid a cooling as possible is
necessary.
This improved blast drying annular kiln thoroughly fulfils all the above named
conditions, a thoroughly clean and evenly coloured article is produced, and a very
considerable saving in fuel and time is effected.
A portion of the drying annular kiln is shown in the accompanying drawings-
Figure 1 being a vertical longitudinal section ;
Figure 2, a plan view partly in section.;
Figure 3, a vertical section through the end kilns 1, 16 and 15.
Figure 4 shows on a larger scale an otherwise ordinary slide or damper such as
is employed for closing the passages so as to be air tight.
Figure 5 is a vertical longitudinal section through the kilns;
Figure 6 is a longitudinal transverse section of a single kiln through line a,
Figure 5;
Figure 7 is a vertical cross section of a kiln through line y y, Figure 5.
Figure 8 is a similar section through line, Figure:5.
The 16 kilns shown in the drawing have an elongated rectangular form, but of
course a circular, oval or other suitable form in which the kilns are placed together
may be equally well selected.
The separate kilns are indicated by numbers from 1-16, and each separate kiln
is connected with its neighbouring kiln and with the chimney by means of passages
which may be gas-tightly closed by means of the slide shown in Figure 4.
Kilns Nos. 1 and 9 lying diagonally opposite have double fire places b which are
so positioned as to be fired from the outside of the ring of kilns, whilst the fire
places of the other kilns are so positioned as to be fired from the inside of the
ring of kilns as will be readily seen from the drawings. The fire places 6 of these
two diagonally opposite kilns are not placed in the same relative positions as the
other fire places'bi, as such position would make it inconvenient for firing owing to

page_text: the arrangement and position of the other kilns. The general arrangement of the
kilns as such differs from the ordinary arrangements chiefly in that the heating
gases are conducted from one kiln to the other as well as in the method of pouring
the damping down substance into the white hot kiln. In each of these improved
kilns or chambers the gases from their respective fire places pass under the floor as
in ordinary damping or drying chambers by passages C and rise through interstices
therein into the chambers. A perforated partition B is however further arranged
between the firing holes 6 or bias the case may be, and the actual chambers A,
the fire gases passing through this partition are evenly distributed along the whole
length of the kiln. Instead of conducting the fire gases from each kiln directly
into the chimney, each kiln is connected with its neighbouring kiln by means of
passages e which may be shut off by means of sand slides or dampers f.
The working of the kilns is as follows:-
C
Assuming for instance that kiln 1 is heated, its connecting passages with kiln 16
and with the chimney are closed, the gases from kiln 1 pass through the two
vertical niches d placed at the rear end of the kiln (ie. at the end opposite to that
where the fire hole is placed) into the passage e leading to kiln 2. From here they
pass through two cross openings c extending from the kiln walls into the passages
running under the kiln. The cross slots c are arranged in such a position that they
lie at about of the length of the chamber from the perforated partition B or from
}
the grate, by which means as even a heating as possible of the whole kiln chamber
is obtained, as the central and rear part of the kiln chamber is first heated. The
hot gases flow from kiln 2 through the niches d, passage e and slots e into the
chamber or kiln 3, and so forth up to the chamber 7 which is the last one which
has been charged and connected up to receive the hot gases from whence they are
conducted into the chimney at a temperature of about 50 degrees Celsius. The
chamber or kiln 8 is just being re-charged, chamber 9 is empty ready for
re-charging, chamber 10 is being emptied of its previous charge, and chambers il
to 16 are being left to cool preparatory to emptying, so that chamber 11 is almost
quite cool, whilst the following successive chambers 12 to 16 have a temperature
which increases from chamber to chamber. If the firing has been completed in
kiln 1, all the various slides (valves) and firing doors are closed so as to be gas
tight and the damping substance poured into the kiln by means of siphons & through
the upper openings o. These openings o which may be of any suitable number are
arranged so that, say three of them are directly over the fire, three others over the
rear end and three others over the centre of the chamber. By the use of siphons
for pouring in the damping down material, the access of air into the chamber is
prevented and the damping material is equally distributed.
After the cessation of the direct firing of chamber 1, chamber 2 is fired and the
hot gases are conveyed from the chamber 7 further into the next chamber 8 and
only out of this latter to the chimney. In a similar way when chamber 2 has been
fired, the chamber 9 is heated and so forth. By this method of firing, that is to
say by carrying the hot gases through a number of chambers before they pass into
the chimney, the chambers before they are directly fired are warmed to a red heat,
so that the actual firing requires 3 to 4 days less time. Less bricks are also
damaged during their first heating, as the bricks just inserted are only exposed to a
moderate temperature of about 50 degrees Celsius, that is to say are only slowly
warmed. Further, as only one of the whole series of chambers is directly fired at
a time, the consumption of fuel is only one third as much as when each separate
chamber is directly fired.
The rapid cooling of the chambers after the damping down, is brought about in
the usual manner by strongly moistening with water the sand contained between the
inner and outer walls of the kiln, such water being rapidly evaporated by the hot
inner walls and heat being rapidly withdrawn from the chamber. When the
chamber is fully cooled, its charging doors a are opened aud the chamber emptied
These doors a consisting of two thin walls, the spaces between which are filled with
sand may be arranged at any desired part of each chamber. It is quite immaterial

page_text: the burning or damping down process whether these doors a are directly beside
the fireplace or on the opposite side. The doors are built up again after each
charging of the kiln and have no influence on the process of the burning or
lamping.
The slide for shown in Figure 4 consists of two sheet metal plates i provided
with angle irons i¹, which plates are placed in a groove of the passage e or e¹ fine
sand being filled in between the two plates and rammed in. This arrangement has
been found the best for making a gas tight joint. All the chambers are connected
with the main passages E leading to the chimney G by means of passages el
capable of being' closed by means of slides f', thus enabling the draught to be
exactly regulated by means of valves g arranged in the main passages E and seated
on sand.
The drying process for each kiln is reduced by the improved arrangements
hereinbefore described, from 14 days to 10 days.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
ne by my foreign correspondent, I declare that what I claim is :-
1. An improved method for the continuous working of annular and the like kilns,
consisting in having only one chamber at a time fully fired and passing the hot
gases from such chamber through a series of successive chambers before escaping
into the chimney whereby the latter chambers are heated before being successively
fired.
2. An improved continuous working annular or the like kiln, in which each
chamber is connected with the chimney and with the adjacent chambers by means
of passages which may be closed air tightly by sand slides in such a way that only
one chamber at a time is being fully fired whilst the hot gases from such chamber
are passed through a series of successive chambers before escaping into the
chimney, the transfer of the hot gases from one chamber to another being effected
by niches arranged at the end of each chamber which niches open into a connecting
passage from which the heated gases flow through two cross slots into the next
chamber, these slots being arranged at about one third of the length of each
chamber and each commencing at the wall and rising to the passages running under
the floor of the chamber substantially as and for the purpose described and
illustrated.
3. In an improved kiln such as described, the use of siphons for pouring the
damping down material into the chambers whereby atmospheric air is prevented
from penetrating into the chamber during the pouring in operation, substantially
as described and illustrated.
Dated this 27th day of June 1894.
WM. P. THOMPSON & Co.,
Agents.