Improvements in Kilns or Ovens for Firing Terra-cotta and other like Materials.
Year: 1891

page_text: Date of Application, 24th Oct., 1891-Accepted, 26th Mar., 1892
COMPLETE SPECIFICATION.
Improvements in Kilns or Ovens for Firing Terra-cotta and other
like Materials.
We, CHARLES DUBOIS D'ENGHIEN, ALPHONSE DUBOIS D'ENGHIEN and
SILVAIN DUBOIS D'ENGHIEN, all of Hennuyères in the Kingdom of Belgium,
Tile Manufacturers, 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 kiln or oven forming the subject of the present application has very great
advantages over ovens of other systems hitherto employed.
These advantages are
1. Considerable economy of fuel.
2. Great uniformity of baking because all the baking compartments with the
exception of the two extreme ones are rectangular and because the draft always
takes place in a regular manner by two conduits of equal dimensions placed at
each side of the oven and meeting at the centre of the width thereof.
We would draw attention to this mode of draft which constitutes one of the
principal points of our invention.
This advantage is equally obtained in the two extreme compartments by means
of the peculiar construction of these latter, which will be pointed out in the
description of the oven.
3. The great facility with which the oven can be charged and emptied by means
of the inclination given to the lower part of the baking compartments.
4. The heating and cooling taking place in a progressive manner and the
products being uniformly baked all the latter are of first quality.
5. In consequence of the heating being progressive the oven can be charged
with articles not entirely dry.
6. All the firing or baking compartments being separated and the draft taking
place through the divisions existing between them, the compartment situated next
to the last one fired, does not receive any steam.
7. A great economy of labor in the heating, the baking being much more rapid
than in ordinary ovens.
8. The facility for taking the heat from the compartments in cooling by the
apertures made in their arch, when a drying room is constructed above the oven,
this taking of the heat does not in any way abate the progress of the fire, as this
latter is accelerated by the air which enters by the ashpit.
9. The possibility of charging the compartments entirely with glazed goods, for
works only manufacturing this class of merchandise.
10. The advantage of being able to heat with wood or coal according to the
nature of the fuel which the country produces.
11. The articles placed near to the grates, having been brought to a high
temperature when the fire at each of the grates is first lighted, do not take any
discoloration from the fire and have on the contrary, as also the entire baked
charge in a compartment, a very beautiful tint, however delicate they may be.
12. As the baking is always uniform it does not require much precaution on the
part of the stoker who needs only a very short apprenticeship to thoroughly
understand the matter. It follows that as this task does not require much skill or
knowledge, it can be given to a labourer whose salary is not so large as that of a
skilled workman.
13. The diminution of the superintendance or inspection of the foreman on
account of the great uniformity of the baking and who has only to stop it if the
stoker does not do so.

page_text: 14. The facility for drying the articles to. be baked on the upper part of the
oven which remains quite free the firing taking place at the side.
15. The first cost of building the ovens being small and the cost of keeping in
repair nothing, there follows a very marked diminution of general cost which is a
grent advantage in point of view of competition.
16. The facility with which the fuel is thrown on to the grate.
In order that our said invention may be clearly understood we will describe the
same in connection with the accompanying drawings in which,
Fig. 1, shows our oven partly in elevation and partly in section drawn on the
line a, b, c, d, of Figure 3.
Fig. 2, is a section on the line e, f, g, h, of Figure 3.
Fig. 3, is a plan view and a section drawn on the line i, j, k, l, of Figure 1. This
figure and Figure 1. have parts omitted between the lines, s, for want of space.
Fig. 4, is a front view of the door of the furnace, showing also the manner in
which it is kept in place.
Fig. 5, is a section of the door.
Fig. 6, is a section on the line m, n, of Figure 8 showing our system applied to
an intermittent oven composed of four baking compartments.
Fig. 7, is a section on the line o, p, of Figure 6.
Fig. 8, is a section on the line q, r, of Figure 6.
Description of the kiln or oven with continuous fires.-
The oven with continuous fires is composed of two arched and parallel galleries
of baking compartments marked 1, 2, 3, 4, and 7 for the first and 9, 12, 13, 14
and 15 for the second, joined together at their extremities by two curved.compart-
ments 8 and 16, which are gradually narrowed or tapered in form. The narrowing
of the compartment 8, commences at the compartment 7 and gradually increases
to the compartment 9; that of the compartment 16 commences at compartment 15
and gradually increases to compartment 1.
This arrangement has for its object to force the gases coming from the
chambers 7 and 15 to come against the exterior walls of the chambers 8 and 16
and to pass through the whole of the articles to be baked contained therein which
would not take place if they were all of the same width, for then the gases meeting
with no obstacle, would take the shortest route by following the interior walle A A
Figures 1 and 3 and would only imperfectly bake the products placed against the
exterior walls.
Between the compartments are placed the grates B₁ B' &c. which receive the
fuel. Below these grates are the ashpits C, C, C, which communicate by the
subterranean flues D E and F with the two principal flues G G which com-
municate with the chimney H which is of sufficient height to assure a good
draught.
Each flue F is furnished with a register 1' 1' &c. by means of which its
communication with the principal flues G G may be interrupted.
This register may be horizontal as shown at Figure 2, a vertical register may
also be used sliding in a frame placed outside the walls supporting the arches.
In this case all the floors of the conduits and of the ashpits are on the same
level. The length of the grates B' B' &c. as shown at Figure 1, forms a separation
chamber between two baking compartments.
In front of the grates B¹ B* &c. are the entrance doors J' J' &c. Figures 12
and 3 of the baking compartments. In the upper arch of the baking compartments
are formed apertures fitted with cast iron pipes K K Figures 12 and 3 which rest
on the arch by their flanges these pipes K K are closed at their upper end by bell
shaped pieces L L Figures 1 and 2.
In order to avoid loss of heat the walls forming the masonry of the oven are
hollow and filled with sand as represented at M M as also the space N comprised
between the upper part of the arch and the brick floor O, surmounting the oven.
These thicknesses of sand may be varied.
As may be seen in the drawings the floor of the baking compartments is not

page_text: orizontal but inclined. This arrangement has for its object to facilitate the
charging and emptying of the baking compartments.
÷
At the side of the grates B₁ B &c. at P P are small walls inclined in the
opposite direction to the floor of the baking compartments. On these small
valls P P a perforated wall may be erected as shown at Q.
This wall is necessary when baking tiles, drain pipes or other articles which
whilst being baked require support.
In practice we do not make this wall a permanent one, we prefer to build it of
unbaked bricks against which the other objects to be baked lean, thus preventing
any loss as the bricks after having served to make the wall are sold.
The working of the oven with continuous fire is as follows :—
We commence by erecting a provisional wall R at the side of the grate B₁ of
compartment 1. where the working commences, that is to say at the end of the
curved compartment 16. Bars S Figure 2 or a cast iron plate are placed in con-
tinuation of the grate. On these bars two provisional walls T and U Figures 2
& 3 are erected with dry bricks that is to say without the use of mortar. The
walls T and U are distant from each other about 15 to 20 centimetres. This space is
filled with sand so as to prevent all loss of heat. The exterior surface of the
wall U is covered with a mixture of clay and sand in order to fill up the crevices
left between the bricks.
At the bottom of the walls T and U an opening is left to receive the door V
of the furnace. This door V as shown at Figures 4 and 5 is hinged in a frame W.
This frame has at its upper part two projections X X which serve to maintain it
in place by means of a bar Y whose extremities engage in two openings made in
the walls forming the doors J₁ J' &c. as shown at Figures 4 and 5. The door V
is of the required thickness and it is made in divisions. These divisions are filled
with brick or other material being a slow conductor of heat see Figure 5. The
walls R. T and U being constructed and the door V placed in position the com-
partment 1 is charged through the door J'. There are constructed in the door J'
the same walls as in the door J¹ excepting that the opening left by the door is
filled up by bricks as represented at Z. Z. Z. and the opening of the ashpit by an
iron plate ZZZ Figures 2 & 3. When this is done the perforated wall Qis
constructed on the little wall P of compartment 2 on the face A³ of which paper
is cemented to intercept all communication with compartment 1.
All being in place as above described the register I' is opened and the fire is
lighted on the grate B¹. The gases then follow the direction of the arrows H
Figures 1 and 3 in order to enter the principal flue G³ and bake the articles in
compartment 1 whilst compartment 2 is being charged.
When compartment 2 is charged, the walls of the door J' are then built up in
like manner to what was done for the doors J' and J and on the little wall P of
the compartment 3, a perforated wall Q is built similar to that in compartment 2
and a paper screen similar to that in compartment 2 is cemented thereon.
This being accomplished the register l' is closed and 1 is opened. This is
what then takes place. The gases no longer escaping by following the direction
of the arrows H' come in contact with the paper screen cemented over the
perforated wall of compartment 2 and burn it. The gases then follow the direction
of the arrows H'.
The same proceeding is followed in the other compartments excepting in com-
partments 8 and 16 the floor of which is inclined on the side opposite to the
doors J & J1 and through these doors the said compartments are charged.
The paper screen is placed in these compartments before the charging is
completed.
The progress of the baking is controlled by the openings K. K. by raising the
bells LL. When the articles placed in compartment 1, are baked a door is
placed in front of the opening J left in the wall for this purpose and the iron
sheet Z' which covers the opening to the ashpit is removed.
Some fuel is thrown on the grate B' which being very hot takes fire. The

page_text: opening of the door J' is then closed with bricks after having removed the door
of the furnace and the opening of its ashpit is closed by an iron sheet covered
with sand.
In Figure 1. it is the register 13 which is represented open and the gases in such
case follow the direction of the arrows H' Figures 1 and 3.
In order to prevent as much as possible the loss of heat from the compartments
the contents of which are baked, the bricks of the provisional wall R are gradually
removed until the wall is completely demolished as also the wall of the door |
for the discharge.
When the oven is working the cold air serving to cool the compartments enters
by the discharge door.
We will now describe the oven with intermittent fire and two galleries.
This oven is but a part of the oven with continuous fire and has the same
arrangements except that it has only one communication between the two galleries
and is formed at the other end by a full wall shown by the line 8. t, Figure 3.
This oven has the advantage of being able after a while to be completed and
transformed into an oven with continuous fire by demolishing the wall s. t. and by
adding the desired number of baking compartments. As will be seen it is very
advantageous when commencing works of this kind which have not yet a trade
large enough to be able to utilize an oven with continuous fire.
We will now describe the oven with intermittent fires having one gallery in a
straight line.
As shown at Figures 6, 7 and 8 an oven with intermittent fires having one
gallery in a straight line can be constructed on the same principle. The internal
arrangements are the same with the exception of the last compartment, 4, the
grate of which is replaced by two openings A³ A³ see Figure 8, communicating
with the principal flue leading to the chimney.
The putting into working order and the working of the ovens with intermittent
fires are identical to those of an oven having a continuous fire.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is.
1. In an oven having a continuous or intermittent fire the arrangement which
consists in constructing the baking compartments varying in number, side by
side and separated by the grates upon which the fuel is thrown as described and
shown in the drawings.
2. The peculiar arrangement and construction of kiln cr oven the system being
applied either to an oven with continuous fire or to an oven with intermittent
fires, having either one or two galleries the number of baking compartments and
their dimensions being varied as may be desired.
3. The method of draught taking place on each side of the oven with equal
force thereby rendering the baking uniform.
4. The establishment of hearths at a sufficient distance from each other to leave
between them compartments sufficiently large in which the most delicate articles
can be baked.
Dated this 24th day of October 1891.
CHARLES DUBOIS D'ENGHIEN.
ALPHONSE DUBOIS D'ENGHIEN.
SILVAIN DUBOIS D'ENGHIEN.
By Harris & Mills,
Southampton Buildings, London, W.C., Agents.