A New System of Reverberatory Furnace with Retorts for Calcining Divers Products.
Year: 1897

page_text: Date of Application, 18th June, 1897
Complete Specification Left, 18th Mar., 1898-Accepted, 7th May, 1898
PROVISIONAL SPECIFICATION.
A New System of Reverberatory Furnace with Retorts for Calcining
Divers Products.
I, HENRI MAWHOOD, of Rempart d'Hoboken, Antwerp, Belgium, Engineer, do
hereby declare the nature of this invention to be as follows:
The object of the present invention is a reverberatory furnace intended for
calcining divers products in closed vases, under heating conditions which are an
improvement over the system of heating actually employed.
The object of my invention is:
1. To equally distribute the heat over the whole surface of the retorts so as to
obtain a regular calcination of the matter contained in the latter.
2. To make the retorts last longer by avoiding their direct contact with the
flames.
3. To reduce the consumption of combustible by a better distribution and utili-
zation of the heat.
In fact the products of combustion not being in direct contact with the retorts
as in the old system, but circulating in flues made of refractory earth which obliges
them to pass successively over all the faces of the retorts, the entire surface of the
latter is subjected to the action of the heat which is uniformly distributed by the
flues, and thus penetrates also into the whole mass of substances to be calcined.
In the old system on the contrary, the parts of the retorts subjected to the action
of the flames receive too great an amount of heat at the expense of the surfaces
which are not directly exposed to the action of the furnace.
The flues are arranged in such a way that the lower retorts, which are nearest
to the furnace, and which would be directly subjected to the action of the flames are
preserved from the flames by refractory bricks which support them and under
which passes the products of combustion.
These consequently, are only in contact, with the retorts, after having first given,
to the refractory bricks among which they have circulated, a great part of their
heat and after having thus lost some of their intensity; moreover, they only pass
above the retorts or over their lateral faces, the flue vault chiefly exposed to their
action being always composed of flags made of refractory clay.
In a word, in the space travelled over by the products of combustion, the retorts
are not in direct contact with the flames, thus avoiding the over heating which has
such a considerable destructive effect; from this results a great increase in the
duration of the retorts.
The refractory earth masonry which constitutes the flues, and the interior lining
of the furnace, has besides the advantage of forming the heat chamber and to
issue this heat in a uniform way, even when the heating is not done regularly.
In fact, if the heat becomes too intense the caloric is absorbed by the refractory
earth masonry; but this masonry having a relatively considerable volume as
compared with that of the retorts and being a bad conductor of heat, only transmits
this heat to the retorts little by little.

page_text: Also if, momentaneously, a fall of temperature is produced, the retorts are pre-
served from sudden variation, by the flues which have stocked, in proportion to
their volume, a certain quantity of heat which they only remit by degrees owing to
their being a bad conductor of heat thus maintaining, for a certain time, a constant
temperature.
It is not the same with the old system which is contrary to a good utilization of
heat; in fact, when a rise of temperature is produced, the retorts being unable to
absorb all the heat disengaged on account of their feeble volume, a large quantity
of this heat is carried away to the outside and lost; if, on the contrary, the tempera-
ture falls, the retorts, owing to the strong conducting properties of the metal,
immediately yields a part of the heat and the calcination is operated in a very
irregular way and is consequently defective; moreover the retorts are thus subject
to a variation of temperature producing expansion and contraction which affect
their duration as well as that of the furnace.
Consequently my system realizes the following improvements on the old system;
1. Equal distribution of heat and regular calcination of substances.
2. Longer duration of the retorts.
3. Reduction of the consumption of combustible.
A New System of Reverberatory Furnace with Retorts for Calcining
Divers Products.
I, HENRI MAWHOOD, of Rempart d'Hoboken, Antwerp, Belgium, 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 present invention relates to a reverberatory furnace intended for the calci-
nation of different products in closed vessels under heating conditions which offer
an advantage over the actually employed system.
The object of my invention is:
'
1) To distribute the heat equally, over the whole surface of the retorts in order
to obtain the regular calcination of the substance placed in the latter..
2) To extend the duration of the retorts by avoiding their direct contact with
the flames.
3) To reduce the consumption of combustible by a better distribution and utiliza-
tion of heat.
Indeed, the combustion products, not being in direct contact with the retorts as
with the old system, but circulating in earthen fire-proof flues which oblige them
to pass successively over all the faces of the retorts, the entire surface of these
latter is subjected to the action of the heat which is uniformly distributed by the
fire-proof pieces or bricks and thus penetrates also into the whole mass of the sub-
stance to be calcined.
With the old system, on the contrary, the parts of the retorts subjected to the
action of the flames receive too great a quantity of heat at the expense of the sur-
faces which are not directly exposed to the action of the furnace.
The flues are arranged in such a way that the lower retorts which are the nearest
to the fire, and would be directly subjected to the action of the flames, are pre-

page_text: served by the fire-proof parts which support them and underneath which the com-
bustion products are passing. The said products are, consequently, only in contact
with the retorts after having yielded a great part of their heat to the fire-proof
bricks between which they have circulated and after having thus lost a part of
their intensity; moreover, they only pass above the retorts or over their lateral
faces, the vault of the flues principally exposed to their action, being always made
of fire-proof flags.
Summarily, along the passage pursued by the combustion products the retorts
are not in direct contact with the flames, and thus avoid the burns of a great
destructive effect; the result of this is a great increase in the duration of the
retorts.
The fire-proof brick-work forming the flues and the interior facing of the furnace
has, moreover, the advantage of forming the heat reservoir and of emitting this
heat uniformly even when the firing is not conducted regularly. Indeed, the heat
becoming too intense, the caloric is absorbed by the fire-proof brick-work; but
this said brick-work having a volume comparatively considerable with respect to
that of the retorts, and being a bad conductor of heat, only transmits it to the
retort little by little. Also, if momentarily, a decrease of temperature is unex-
pectedly produced, the retorts are preserved from a sudden variation, by the fire-
proof bricks which, according to their volume, have stored a certain quantity of
heat which they only restore little by little according to their bad conductibility,
thus maintaining a constant temperature during a certain time. It is not so with
the old system which is opposed to a good utilization of the heat; when a rise of
temperature is produced, the retorts being unable, according to their small volume,
to absorb all the heat disengaged, a great part of this heat is carried outside and
lost; if on the contrary, the temperature falls, the retorts owing to the good con-
ductibility of the metal, immediately yield a part of the heat and the calcination is
effected irregularly and consequently defectively; moreover the retorts thus endure
variations of temperature which produce effects of dilatation and contraction
prejudicial to their duration as also to that of the furnace.
My system consequently realises the following improvements over the old
system :
1) An equal distribution of the heat and a regular calcination of the substance.
2) Extended duration of the retorts.
3) Reduction of the consumption of combustible.
In the annexed drawing a form of execution of my furnace is shown the said
furnace, in its ensemble and details, can have variations in the execution according
To the number of retorts to be placed.
Fig. 1 is a transverse section through the middle of the furnace taken on the
line E F of Fig. 2.
Fig. 2 is a longitudinal section of the furnace, taken on the axis A B of Fig. 1.
Fig. 3 is a longitudinal section of the furnace taken on the line CD of Fig. 1.
The furnace is composed of a brick wall-mass the centre part of which is empty,
faced with fire-bricks and arranged to receive a certain number of retorts under a
vault.
In the case indicated in the drawing the furnace has five retorts in two super-
posed rows, three at the bottom, and two at the top.
The hearth is arranged under the central retort P of the lower row and the com-
bustion products are divided into two currents which, passing through the passages
made between the fire-proof bricks B, heat the two flues S situated under the lateral
retorts Q of the lower row and heat these retorts which are preserved from the
flames by the fire-proof bricks E.
The combustion products then pass through the passages arranged between the
pieces G and I (Fig. 3) to heat the lateral and upper parts of the same retorts Q
and so also the lateral outer faces of the 2 retorts R of the upper row; then passing
through the two passages T (Fig. 3) arranged in the bottom of the furnace behind
the flags N they come under the vault of the furnace and heat the top of the two

page_text: upper retorts R and then go through the passage made in front of the flags O into
the only flue V (Fig. 2) leading towards the exit-port; during this latter course,
they heat the top and sides of the central retort P and the inner sides of the upper
retorts R. The combustion products then arrive at the exit-port where the draught
is regulated by a damper T (Fig. 2).
The course of the combustion products is indicated in the drawing by arrows.
Having now particularly described and ascertained the nature of my said inven-
tion and in what a manner the same is to be performed, I declare that what I
claim is :-
1) In a reverberatory retort-furnace for the calcination of different products in
closed vases the arrangement to allow a regular distribution of the heat the absence
of direct contact of the flames with the retorts thus obtaining a regular calcination
of the substance, a longer duration of the retorts and an economy of combustible
substantially as described.
2) A form of construction of the furnace claimed in 1) distinguished by the
arrangement of the retorts on fire-proof flags forming flues over all the faces of
the retorts, in which flues the combustion products circulate, these products yielding
nearly their whole caloric to the fire-proof bricks, the calorific capacity of which is
very great and which are, in short, reservoirs storing heat and distributing it
uniformly over the whole surface of the retorts in preserving these retorts from the
action of the flames which oxidate and deteriorate them quickly, as and for the
purpose set forth.
Dated this 17th day of March 1898.
L. DUVINAGE,
Patent Agent, 8, Rue des Princes, Brussels, Belgium.