IMPROVEMENTS IN STEAM BOILER FURNACES
Year: 1862

page_text: LETTERS PATENT to Maro Antoine François Mennons, of the British and
· Foreign Patent Offices, 24, Rue du Mont Thabor, Paris, in the Empire
of France, for the Invention of "IMPROVEMENTS IN STEAM BOILER
FURNACES," A communication from Frédéric Emile de Erlanger and,
Alexandre Friedmann, residing at No. 21, Rue de la Chaussée d'Antin,,
Paris, France.
PROVISIONAL SPECIFICATION left by the said Maro Antoine François
Mennons at the Office of the Commissioners of Patents, with his
Petition, on the 25th June 1862.
I, MARC ANTOINE, FRANÇOIS MENNONS, of the British and Foreign Patent.
Offices, 24, Rue du Mont Thabor, Paris, in the Empire of France, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN STEAM BOILER
FURNACES," (a communication) to be as follows:-
This Invention consists in the application, as hereafter described, to the
fire-boxes of steam boiler furnaces of an inner mantel or diaphragm so
arranged as to form a reverberatory chamber, in which are effected the heating
of the atmospheric air required for the combustion of the smoke and its
distribution over the ignited surface of the fuel on the grate.
The accompanying Drawings represent, as example, an application of the
Invention to an ordinary locomotive furnace.

page_text: Figure 1 is a longitudinal section of the fire-box with its mantel; Figure 2
is a horizontal section of the same through the line A, B; Figure 3 is a
cross section through C, D; Figure 4 is an end view. In all these Figures
the similar parts of the combination are indicated by the same letters of
reference.
H is the mantel, constructed of thick sheets of wrought or cast iron, copper,
or steel; or again, in certain cases, of refractory clay, descending from over
the furnace door to a certain distance above the fire-bars, varying from ten
to twenty inches, according to the average depth of the fuel layer. a, c, are
brackets and bolts, by which this mantel is so attached to the furnace as to be
readily dismounted and replaced at will. The surfaces of the mantel in close
proximity to the grate are provided with strong sheet metal linings, as in d,
or again, with a cast-iron band, to enable them to resist the direct action of
the fire; p, p, are two ports fitted to the fire-box to permit of inspecting at
will the combustion in the sides of the furnace, as also the tube plate q, q,
which is concealed by the mantel from the fire-door P. If preferred, these
ports may be replaced by a door set in the back of the mantel itself. When
allowed by the general construction of the boiler, a number of small tubes may
be fitted in the front of the fire-box, as seen in x (Figs. 1, 4), and closed at
will by a valve v, or by a register worked by the rod w. The object of this
arrangement is to permit of closing the fire-door P when the engine is at rest,
while supplying a horizontal current of air to the ignited surface of the fuel.
During the stoppages the combustion is kept up by aid of a blower, with
which the boiler is provided. The mode of protecting the lower part of the
mantel from the action of the fire may be varied according to circumstances.
Thus, for instance, a canal may be formed between the metallic linings d
to serve as conduit for the air from without, which is heated in its passage and
escapes into the mantel space. Instead of this circulation of air a current of
water may be admitted from the tender, to which it is returned by suitable
conduits when heated by its passage round the mantel. Or, again, the canal
may be replaced by a series of tubes serving as. conduits for air or water, as
above. The form and dimensions of the mantel may vary with those of the
furnace and with the degree of inclination of the grate, the construction of
which requires no modification. The fuel is supplied to the furnace by the
fire-door P, which is always kept more or less open to allow the passage of
the air. The air thus admitted into the mantel absorbing the caloric of the
metal is heated to a high degree, and passing downwards towards the fuel
layer, mingles with the gaseous products of the combustion, which are thus
entirely consumed. The introduction of air is regulated at will by the notched

page_text: bar K, which maintains the door P in the required position. When the action
of the chimney is suppressed by the stoppage of the engine, the blower may be
opened to produce a draught, which forces the air passing by the fire-door to
turn over (" se renverser ") in the entire height of the mantel. Should it bo
preferred to keep the door closed, the valve r is opened to admit the air by
the tubes a When the engine is again started the valve is closed, as before,
and the fire-door opened to the point required for the admission of a due
supply of air.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Marc Antoine François Mennons in the Great Seal Patent
Office on the 18th December 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARO
ANTOINE FRANÇOIS MENNONS, of the British and Foreign Patent Offices, 24,
Rue du Mont Thabor, Paris, in the Empire of France, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of June, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Marc Antoine François Mennons, Her special licence, that I, the said
Marc Antoine François Mennons, my executors, administrators, and assigns,
or such others as I, the said Marc Antoine François Mennons, my execu
tors, administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend, within
the United Kingdom of Great Britain and Ireland, the Channel Islands, and
Isle of Man, an Invention for "IMPROVEMENTS IN STEAM BOILER FURNACES,"
a communication from Frédéric Emile de Erlanger and Alexandre Friedmann,
persons resident at No. 21, Rue de la Chaussée d'Antin, Paris, France, upon the
condition (amongst others) that I, the said Marc Antoine François Mennons,
my executors or administrators; by an instrument in writing under my, or their,
or one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention; and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the said
Letters Patent.
:
NOW KNOW YE, that I, the said Marc Antoine François Mennons,
do hereby declaro the nature of the said Invention, and in what manner the

page_text: same is to be performed, to be particularly described and ascertained in
and by the following statement, reference being had to the Figures of the
accompanying Drawings, and to the letters' marked thereon, that is to
say:-
+
This Invention consists in the application, as hereafter described, to the
fire-boxes of steam boiler furnaces of an inner mantel or diaphragm, so
arranged as to form a reverberating chamber, in which are effected the
heating of the atmospheric air required for the combustion of the smoke,
and its distribution over the ignited surface of the fuel on the grate.
Figures 1, 2, 3, 4 of the annexed Drawings represent, as example, an
application of the Invention to an ordinary locomotive furnace.
Fig. 1 is a 'longitudinal section of the fire-box with its mantel; Fig. 2 is a
horizontal section of the same through the line A, B; Fig. 8 is a cross
section through C, D; Fig. 4 is an end view.
II is the mantel, constructed of thick sheets of wrought or cast iron, copper,
or steel; or, again, in rare cases of refractory clay descending from over the
furnace door to a certain distance above the fire-bars, varying from ten to
twenty inches, according to the average depth of the fuel layer. In no case
should the thickness of the metallic sheets be less than one quarter of an
inch, experience having proved this to be the lowest point at which they can
retain a sufficiency of caloric for heating the amount of air required. A, C,
are brackets and bolts, by which this mantel is so attached to the furnace as to
be readily dismounted and replaced at will. The surfaces of the mantel in
close proximity to tho grate are provided to a height of at least four inches
with strong sheet metal linings, as in D; or, again, with a cast-iron band, to
enable them to resist the direct action of the fire. The thickness of metal at
this point should never be less than three-fourths of an inch. P¹, P¹, are two
ports, fitted to the fire-box to permit of inspecting at will the combustion in
the sides of the furnace, as also the tube plate Q, Q, which is concealed by
the mantel from the fire-door P. If preferred, these ports may be replaced
by a door set in the back of the mantel itself; a small self-closing trapway
may also, if desired, be formed in each side of the mantel to facilitate the
uniform charging of the fuel in the sides of the grate. When allowed by the
general construction of the boiler, a number of small tubes may be fitted in the
front of the fire-box, and closed at will by a valve or by a register worked by a rod.
The object of this arrangement is to permit of closing the fire-door P when
the engine is at rest, while supplying a horizontal current of air to the ignited
surface of the fuel. During the stoppages the combustion is kept up by aid
of a blower with which the boiler is provided. The mode of protecting the

page_text: lower part of the mantel from the action of the fire may be varied according
to circumstances. Thus, for instance, a canal may be formed between the
metallic linings D to serve as conduits for the air from without, which is
heated in its passage round the mantel. Or, again, the canal may be replaced
by a series of tubes, serving as conduits for air or water, as above. The
simple lining constructed and applied, as shewn in the Drawing will, however,
be generally found sufficient for all practical purposes. The fuel is supplied
to the furnace by the fire-door P, which is always kept more or less open
to allow the passage of the air. The air thus admitted into the mantel,
absorbing the caloric of the metal is heated to a high degree, and passing
downwards towards the fuel layer mingles with the gaseous products of the
combustion, which are entirely consumed. The introduction of air is regu-
lated at will by the notched bar K, which maintains the door P. in the
required position. When the action of the chimney is suppressed by the
stoppage of the engine the blower may be opened to produce a draft, which
forces the air passing by the fire-door to turn over ("se renverser") in the
entire length of the mantel. Should it be preferred to keep the door closed
the air may be admitted by the inlet tubes above mentioned, (when such
exist), which, when the engine is again started, are closed as before by their
valve or register, the fire-door being reopened to the point required for the
admission of a due working supply of air.
Figures 1bla, 2b, represent in longitudinal section and plan a semi-conical
mantel, constructed on the same principle as that above described; Figures 5,
6, 7, represent on a reduced scale an application of the Invention to furnaces,
in which the door is in such close proximity to the grate and to the roof of the
fire-box as to leave insufficient space for the secure attachment of the mantel
to the inner face of the latter. In this arrangement the mantel is modified in
form, as seen in the Drawing, and is firmly bolted to the roof and front of the
fire-box, thus assuring the necessary degree of rigidity, which from the con-
struction of the furnace it would be difficult to obtain by the single front
attachment shewn in the preceding Figures. The door P may be constructed
on the same principle as those above described, or, when sufficient space exists
between it and the roof of the fire-box, it may be reserved solely for the intro-
duction of the fuel, a small port, as in W, Fig. 8, or a series of apertures, being
formed above for the admission of air.
Figure 8 represents an application of the Invention to furnaces, in which, as
in certain descriptions of portable and stationary engines, the door is set close
to the grate, and at a considerable distance from the roof of the fire-box. În
this application the door P remains closed as in ordinary furnaces, but above

page_text: it is formed a small port W, of similar construction to that seen in P, Figs. 1,
2, 4, and reserved solely for the admission of air into the mantel, into which it
issues. When so desired and permitted by the construction of the fire-box,
this second door may be replaced by simple air apertures, as already described.
It will be understood from the preceding description that the main object of
the Invention is to obtain: the intimate mixture of highly heated air with the
products of combustion at the moment of their disengagement, and that to
effect this the proportions, position, and resisting power of the mantel are
points of the greatest importance. Thus, it must contain a large quantity of
matter to enable it to contain a large quantity of caloric; it must present a
large heating surface to enable it properly to divide the air to be heated. It
must be a good conductor to enable it to give up its caloric with facility, and
it must be rigid enough to support, without losing its shape, a high degree of
temperature.
Several essential precautions must be observed in the construction and 1
arrangement of the mantel to enable it to resist the destructive action of the
fire; thus,―
1stly, its surfaces must be kept free from pressure.
2dly, it must be firmly secured in position while so fixed, as to be readily
mounted and dismounted at will, due allowance being made for the indepen- 2
dent dilatation and construction of the fire-box to which it is applied.
3dly, it must be constructed of material of high density, conductibility, and
heat-resisting power; the minimum thickness of such material in its thinnest
parts being one-fourth of an inch, and in those parts in proximity to the grate
three-fourths of an inch; the latter thickness being extended to a minimum g
height of four inches.
4ly, the surfaces which do not come in direct contact with the fire-box
should be inclined towards the surface of the fuel, and their resistance to
vertical flexion must be sufficient to enable them to withstand the highest
degree of temperature to which they can possibly be exposed.
8
It should be well understood, in conclusion, that the above-noted thicknesses
of mantel metal ( inch and inch) are stated as the lowest consistent with
any degree of efficiency, and that they should always be increased in practise
according to the temperature to which the apparatus is to be exposed. Thus,
for instance, in the application to locomotive furnaces in which the metal is 3
most liable to deterioration, the thickness of the upper part of the mantel may
be carried to one half or three-quarters of an inch, and in the lined portion
near the grate to one and a half, one and three-quarters, or even two inches.
In applications to portable and other engine furnaces in which the apparatus

page_text: is less exposed to wear, the thicknesses may vary according to circumstances
between the limits above laid down..
Having now described the nature of the said improvements, and the manner
of carrying them into effect, I would have it understood that I do not confine
myself to the precise details of construction and arrangement above eṇume-
rated, as these may in many points be more or less modified without deviating
from the principles or main features of the Invention; but what I claim and
desire to protect by Letters Patent is, the application substantially as herein
set forth and shewn in the Drawings to the fire-boxes of steam boiler furnaces,
of an inner mantel in metal, of a thickness in its upper or thinnest part supe-
rior to one-quarter of an inch, and surrounded at the bottom to the depth of
at least four inches, by a protective metallic lining, forming at this part a
minimum thickness of three-quarters of an inch, the said mantel being so
arranged as to form an inclined diaphragm or reverberating chamber in and by
which are effected the heating of the air required for the combustion of tho
smoke, and the distribution of this air over the ignited surface of the fuel on
the grate.
In witness whereof, I, the said Marc Antoine François Mennons, have
the grate.
In witness whereof, I, the said Marc Antoine François Mennons, have
hereto set my hund and seni, this Fifteenth day of December, in the
year of our Lord One thousand eight hundred and sixty-two.
M. F. MENNONS. (L.B.)