Improvements in Gas-heated Furnaces for Inclined Gas Retorts.
Year: 1899

page_text: Date of Application, 10th Apr., 1899-Accepted, 27th May, 1899
COMPLETE SI'ECIFICATION.
Improvements in Gas-heated Furnaces for Inclined Gas Retorts.
I, EUGÈNE DERVAL, of 23, Rue Chauchat, Paris, in the Republic of France,
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 relates to improvements in the furnaces of inclined retorts,
the object of which is to improve the working and reduce the cost.
The accompanying sheet of drawings illustrates the application of the said
improvements to a bench of nine retorts for making illuminating gas, it being
understood that the construction and arrangement of the furnace may be varied
according to the number, shape, and dimensions of the retorts employed.
In the said sheet of drawings Figure 1 is a longitudinal section through the
centre of a bench of retorts, Figure 2 a section taken through one of the re-
generators of the furnace. Figure 3 shows four half transverse sections taken on
the lines A-A, B-B, C-C and D-D of Figure 2, and Figure 4 shows four
half horizontal sections taken on the lines M-M, N-N, O-N, and P-P of
Figure 2.
The arrows a indicate the course taken by the air necessary to effect combustion
of the gas generated in the gas producer 1, and the arrows b the course taken by
the said gas on its way out of the said gas producer; the arrows without an
indicating letter show the course taken by the products of combustion.
1 indicates the combustible gas producer fed with coke or coal.
2 the charging throat of the gas producer.
regenerator for utilizing the waste heat of the products of combustion in
order to heat the air necessary for the combustion of the gas generated in the
producer.
4 damper.
5 combustion chamber.
6 flue leading to the chimney.
7 first inlet for hot. air into the combustion chamber.

page_text: Since their introduction for the manufacture of illuminating gas inclined
retorts have not given very good results, chiefly in consequence of the difficulty
of heating them economically and regularly. Furthermore the necessity there
has been of placing the combustible gas producer in such position that it pro-
jects beyond the retort bench in order to have space enough for the regenerators
and the smoke flue, has rendered it very difficult to construct the furnaces
properly. In some installations the charging of the producer, and the cleaning
of the fire-bars, has been done, as in my furnaces, behind the retort benches;
but it has then been necessary to make use of a special floor or platform for
charging the producers so that there were required three different floors or plat-
forms, one for charging the retorts, one for charging the producers, and one for
discharging the coke.
Furnaces constructed according to my invention allow the height of the
bench or retorts to be greatly reduced, and the floors or platforms for discharging
the coke, and for charging the producers to be done away with without its being
necessary to have a special pit for clearing the grate bars. The removal of ashes and
clinker is effected at the level of the floor of the retort house; but a pit may be made
if preferred behind the benches.
In order to charge the producers from the same charging floor or platform as
the retorts I simply do away with the arch over the producer and use instead
thereof the bottom of the middle retort. When the quality of the retorts is not
quite certain it is preferable to support the bottom of this retort on a row of
fire-clay slabs as shown in the drawing. This arrangement is a special feature
of my invention which, combined with my system of burner or gas producer, has
enabled me to reduce considerably the cost of inclined retort furnaces by placing
the producer and the regenerators in the space left by the inclination of the
retorts.
The retorts are supported by transverse walls placed so that the flames or hot
products of combustion follow the course shown by the arrows in the drawing.
The circulation of the flames or hot products of combustion in the direction
indicated, that is to say lengthwise of the retorts, is assumed by a cross wall M
which rises up to the arch of the furnace so as to return the flames or hot products
of combustion under the lower retorts.
Contrary to the usual practice the regenerator is so arranged that the smoke
and waste products of combustion pass into the vertical holes of the brick-work
of the regenerator; but this arrangement is not indispensable, and any other
system of regenerator may be employed for heating the air.
The construction of the gas producer may of course be modified according to
the nature of the fuel employed, without departing from my invention.
It will be seen from Figures 1, 3 and 4 of the drawings that the gas which
escapes at the bottom of the producer 1 can be raised to as high a temperature
as may be required by the introduction at 7 of a sufficient quantity of air. By
regulating this first admission of hot air by the damper of the air inlet of the
regenerator, the bottom of the retorts can always be raised to the required tem-
perature. As regards their upper part, which does not require to be raised to
so high a temperature, for a good distillation, it is only necessary to open appro-
priately the damper X which regulates the second inlet of hot air at 8 (see Figure
2). The small inlets for air shown at 9, one at each side of the charging opening
of the gas producer, are simply for partly turning the gas in the producer
when tor example, in consequence of the employment of coal as fuel, the distilla-
tion is not perfect in the retort placed directly over the producer.
I attach great importance to the use of this arrangement of furnace, for it
enables me to obtain not only a very regular heating of the retorts with coke,
coal, or tar, but also a notable reduction of the quantity of fuel consumed, in
consequence of the better utilization of the heat of the flame or of the products
of combustion. Furthermore the successive combustion to which I subject the
.

page_text: gases before sending them to the regenerator prevent the cutting action of the
fire on the retorts, and the duration of the latter is thereby increased.
This method of heating may also be applied to furnaces of 7 and 8 retorts,
also to furnaces having only two vertical rows of retorts (furnaces with 2, 5.
and 6 retorts). In this latter case the producer is placed at the side of the furnace
under one of the lower retorts. For furnaces having two horizontal rows of
retorts it is sufficient to omit, in furnaces with 7, 8 and 9 retorts, the second row
of retorts without altering the furnace at all or the position of the producer.
Sliding of the retorts and leakages of air through the front walls are prevented
in my furnaces by the employment of a covering of cement 12 in which are em-
bedded the horizontal iron bars which hold in place the cast iron mouthpieces
of the retorts. The ends of these bars are held by small bands of iron rivetted
to the stancheons and other supporting ironwork of the retort bench. This sup-
porting ironwork does not project at all beyond the face of the retort bench,
which is a great advantage when the removal of the coke is effected with wagons
or a quenching conveyor.
I prefer to arrange the ascension pipes and hydraulic main for inclined retorts
in a manner which differs entirely from what has been heretofore employed.
In retort benches for illuminating gas, the ascension pipes which convey the
gas from the retorts to the hydraulic main are usually arranged verti-
cally whether the hydraulic main is placed in front or not of the face
of the benches or furnaces. The result of this is that the weight of the pipes
acts directly on the cast-iron mouth pieces, and tends to detach them from the
retorts. Furthermore there pipes being very close to the face of the bench or furnace
are greatly heated thereby, and the tar deposited in them forms accumulations
which prevent the free escape of the gas. To obviate these inconveniences, known
to every gas works manager, I incline the ascension pipes, and place the hydraulic
main at a tolerable distance from the benches or furnaces. By these means the
weight of the ascension pipes acts much less powerfully on the mouth-pieces of
the retorts; and as the pipes diverge from the face of the furnaces their contact
with the cold air prevents the deposit of the tar in them, and the obstructions
occasioned thereby.
It is obvious that instead of contributing to the sliding downwards of the
inclined retorts the pipes oppose such sliding since they bear against the face
of the furnace by the intermediary of the small feet cast on the upper part of the
cast iron elbows a little below the cleaning plugs (see Figure 1).
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:
First. In a gas-heated furnace for inclined gas retorts, the use of a gas producer
without an arch placed directly below one of the retorts of the lower row in
the space left by the inclination of the retorts, the said gas producer being charged
from behind the retort bench through an opening placed at the level of the retort
charging-floor substantially as described.
Second. In a gas-heated furnace for inclined gas retorts, the use of a principal
combustion chamber placed behind the gas producer for the purpose of heating
the bottom of the retorts, substantially as described.
Third. In a gas-heated furnace for inclined gas retorts arranging the supporting
walls of the retorts so that they form baffles and cause the flame and hot products
of combustion to circulate from the front towards the back, and to change their
direction several times before reaching the regenerator, substantially as described.
Fourth. In a gas heated furnace for inclined gas retorts, the use of a supple-
mentary air inlet near the middle of the course traversed by the flame and hot
gases, for the purpose of completing the combustion of the said gases, substantially
as described.

page_text: Fifth. In a gas heated furnace for inclined gas retorts, the use of a hot air
inlet at each side of the charging opening of the gas producer for the purpose
of partially burning the gas above the fuel in the said producer, substantially
as described.
Sixth. In a bench of inclined gas retorts the use of a cement covering in which
is embedded the ironwork holding in place the retort mouth-pieces, substantially
as described and for the purposes specified.
Seventh. In inclined gas retorts, placing the ascension pipes which connect
the retorts to the hydraulic main at an angle so that they incline away from the
face of the bench or furnace, substantially as described.
THIS TULIT way
ceer und To
E. DERVAL,
Per W. H. Beck,
Agent, 115, Cannon Street, London, E.C.,