Improvements in and connected with Smoke-consuming Furnaces.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in and connected with Smoke-consuming Furnaces.
I, GUSTAV LANGENBACH, of Grabow, near Stettin, in the Kingdom of Prussia,
German Empire, Engineer, do hereby declare the nature of this invention
to be as follows:-
To obtain a smoke-free interior firing, that is to say, for a boiler with one or
more flame-tubes, in which the grate is arranged in the interior of the flame-
tube, it is necessary as it were to divide the grate-surface into two parts, and
to employ the front part as preparatory grate, the so-called coking-grate, whilst
the rear part is employed as burning-grate proper.
The problem is here to cause the fuel of a certain or definite part of the grate-
surface, viz., the rear portion of the grate, to burn with a bright flame, so that
the fire-gases arising from the same may with certainty ignite the cold fire-gases
developed upon the front portion of the grate.
In order to make my invention more clear, I refer to the accompanying draw-
ings, in which similar letters denote similar parts throughout the different views,
and in which:
Figures 1 & 2 show in longitudinal and cross section a construction devised for
the above mentioned purpose and applicable to ordinary flame-boilers, whilst in
Figures 3 & 4 also in longitudinal and cross-section a construction is shown,
devised for ships boilers.
Figures 5 & 6 represent two longitudinal sections of a modified construction.
The grate-surfaces a a¹ a² (Figure 1) consist of one or more series of grate-
bars. In the drawing three positions of such bars are assumed.
Above the grate is freely arranged (Figure 2) a strut frame like erection bbbbb,
which, as shown, consists of five stones, of which bb are the supporting stones, 61 61
the strut frame like part, and 62 the headstone.
The grate a a¹ a² is not closed as usual at the back with a higher fire-bridge,
but has a smooth end; the rear grate-part being by means of the separating
walls ss cut off or divided towards two directions, firstly towards the rear portion
of the flame-tube, as also towards or against the front of the furnace, viz., the part
under the grate a a¹.
Small air-openings a are however arranged or provided in the front wall s.
It is to be remarked, that the two lower portions of the separating walls s s¹ are
removable, so that with ease all parts of the furnace can be cleaned from the
front, and freed from ashes etc.
Behind the separating wall as also behind the said erection bb1b2b¹b, is a
wall e, which tends to draw in, or decrease the diameter, over which the fire-
gases spread or extend.
To explain the modus operandi of my invention I remark as follows:
When the coal, stoked upon the combustion grate-proper a a', in the manner
shown in the drawing, has to a large extent been burnt or consumed a fresh
charge of coal will of course be necessary, hereupon the remaining coal will be
first brought more to the back of the furnace, so that the dotted line ccc will

page_text: become, as it were, the upper dividing line of the fuel, whereupon the furnace will
be again stoked of course at the front portion of the grate as the rear portion of
the same, is prevented or protected by the higher mass of the beforesaid glowing
coal and also by the fire-beam bb' be from receiving any of the charge or coal.
When now the fire-door is closed, the following takes place:
Upon the front portion of the grate a aa coking will take place, for the reason
that the gases generated or developing from the cold fuel, are, as is clear, not hot
enough to be at once ignited. These gases are forced to pass partly over and partly
under the glowing fire-bridge bbbbb and to come in contact with the glowing
coal-mass at z¹.
The decrease of the extent over which the cold gases would otherwise spread,
which decrease as mentioned takes place at the fire-bridge bb1b2b1b, and at the
glowing coal pile at i, causes the cold gases to become heated, and mixed with
the ascending gases at i, whereupon the said cold gases ignite in the space p, if
they have not already ignited in the flues or chambers and p³.
In any case it is certain that before the said gases reach the before mentioned
rear wall e which is also highly heated, they must be ignited, for the reason that
into the mixing space 2 enter not only the hot gases emitted from it but also the
gases which have penetrated the grate a².
Upon this grate-portion a² rests of course only a thin layer of coal, and further-
more only a small air-supply enters through the apertures a³. Thus between
or from this portion of the grate very hot and perfectly ignited gases are
emitted, which mix with the cold gases of the front grate-portion a, and which
at the said wall of contraction e must without doubt ignite and be completely
burnt. As an important feature of this present invention I regard on the one
hand the fire-bridge bb bbb, arranged as above indicated in the form of a
strut frame like erection, whereby the same is capable of resisting every tendency
to bend. This is necessary as the chamotte-stones of the said structure care
always in the region of the hottest fire-gases.
It is also regarded as new that the rear grate-portion a² receives a contraction
of the air-supply, in consequence of the parting-walls (provided with the before-
said openings a³) only permitting a small access of air to this portion of the
grate, whereby 1 attain the following:
Upon this grate-portion a³, as before stated, only the smallest layer of coal
rests, as the stoker cannot with any degree of certainty push the glowing-coal
to the rear part of the grate, without the risk of its falling behind the separating-
wall s'. If this said grate portion a² received a powerful air-supply, the said
thin coal-layer upon a would not only quickly burn through, but such greater
supply of air would cause too strong a draught through the grate-portions a a¹
(for each of which parts a a¹ the fire-bridge bbb hinders the influence of the
stack or chimney), thus a stagnation would take place in the supply of air the
coal would not be consumed in sufficient quantity, the grate-bars would not be
cooled in suitable manner, and furthermore no sufficient development of steam
would take place, nor would the grate be protected from burning. It will be
thus clear, that this contraction of the supply of air to the rear part a² is one
of the most important and characteristic features of the present invention, together
or in combination with the beforesaid strut frame like structure of the fire-bridge.
Such contractions of this description as shown at c, have, it is true, been
hitherto employed for a smooth grate, where behind the grate a fire-bridge not
of any especial height was erected, but such part was not hitherto arranged for
the supply of air to such grate portion or in other words such contraction c had
not been constructed for the "supply" of air to the portion a² of the grate, but
hitherto the "discharging" gases from this said grate portion had been throttled.
This latter system is not however so advantageous, as it is hereby not possible
during the throttling or contraction, and to regulate the same.
This regulation
in the present invention can be easily effected by closing one or more of the
apertures a³, for which reason the arrangement of the contraction or throttling

page_text: of the air supply to the rear portion of the fire-grate, as herein described and
forming, as above mentioned, a feature of my present invention, is preferable to
the methods hitherto known for this purpose.
or the
Whilst the construction represented in Figures 1 and 2 is intended for land-
boilers, the arrangement in Figures 3 & 4 is adapted for ships-boilers. The latter
differs only from the first mentioned, in that the contracting wall c
throttling device of the fire-gases which according to the arrangement of Figure 1
is located at the bottom of the tube, is here (Figures 3 and 4) arranged in the
form of an arch on the upper side of the fire-tube. The gases passing over the
fire-distributing bridge bb bb1b, as also underneath the same, are led downwards
throughout the arched structure c¹ and hereby caused more intimately to mix
with the hot gases coming from a². Of course the same method of this last
mentioned contraction or throttling of the fire-gases may also be employed for
land-boilers. The chief points are the especial arrangement of the boiler and
the supply of air.
In Figure 5 another modification of this arrangement is represented, in which
both the before mentioned strut like frame structure can consist of two parts,
and also the contracting or throttling device of the rear part of the grate is
movably arranged, i.e. movable in an horizontal direction, and adjustable in a
vertical direction, so that on the one part the throttling organ s when moved or
adjusted by hand, in the manner indicated by the drawing Figures 5 & 6, causes
a larger portion of the grate to form a burning grate proper, upon which the
throttling of the air supply acts. This result can also be achieved on the other
hand by locating the throttling device of the air-space between the grate, the
said air-throttling device in a higher position, so that as desired (or optionally),
more or less air can be conducted to the rear portion of the grate.
Figure 5 shows an arrangement of the throttling device s in the modified form,
as above mentioned, but in a rear view and in its lowest position.
Figure 6 shows the same air-throttling devices in its highest position and
furthermore in its most extended position, this position corresponding to the rear
part of the grate form to o in Figure 1, and to a² in Figure 2, for which said
rear grate portion the air-supply is throttled in the manner above described.
Dated this 26th day of August 1898.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.
Improvements in and connected with Smoke-consuming Furnaces.
I, GUSTAV LANGENBACH, of Grabow, near Stettin, in the Kingdom of Prussia,
German Empire, 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:-
To obtain a smoke-free interior firing, that is to say, for a boiler with one or
more flues, in which the grate is arranged in the interior of the flue, it is neces-
sary as it were to divide the grate-surface into two parts, and to employ the front
part as preparatory grate, the so-called coking-grate, whilst the rear part is
employed as burning grate proper.
The problem
here to cause the fuel of a certain or definite part of the grate-
surface, namely, the rear portion of the grate, to burn with a bright flame, so
that the gases arising from the same may with certainty ignite the colder gases
developed upon the front portion of the grate.

page_text: In order to make my invention more clear, reference is made to the drawings
filed with the Provisional Specification, in which similar letters denote similar
parts throughout the different views, and in which:-
Figures 1 and 2 show in longitudinal section and cross-section respectively a
construction of furnace devised for the above mentioned purpose and applicable
to ordinary internally fired boilers, whilst in Figures 3 and 4 also in longitudinal
section and cross-section respectively a construction is shown devised for marine
boilers. Figures 5 and 6 both represent a modified construction in longitudinal
section.
The grate-surfaces consist of one or more series of grate-bars
In the drawing three sets of such bars are assumed.
a² (Figure 1).
Above the grate is freely arranged (Figure 2) a strut frame-like erection or
bridge 261b, which, as shown, consists of five stones or fire bricks, of
which bb are the supports bb the strut frame-like part, and 62 the key-stone.
The grate aa² is not closed as usual at the back with a higher fire-bridge,
but has a smooth end; the rear grate-part a being by means of the separating
walls ss cut off or divided at two places, firstly towards the rear portion of the
flue and also towards or against the front of the furnace namely the part under
the grate a a¹.
Small air-openings are however arranged or provided in the front wall s.
It is to be remarked, that the two lower portions of the separating walls ss are
removable, so that all parts of the furnace can be cleaned from the front with
case, and freed from ashes etc.
1.
Behind the separating wall s¹ and also behind the said erection bb, is a
wall c, which tends to draw in, or contract the area, over which the gases spread
or extend.
I will explain the modus operandi of my invention as follows:-
When the coal, fed upon the combustion grate proper a a', in the manner
shown in the drawing, has to a large extent been burnt or consumed a fresh
charge of coal will of course be necessary. Thereupon the remaining coal will
first be pushed more to the back of the furnace, so that the dotted line cce will
indicate, as it were, the position the fuel will assume, whereupon the furnace will
be again fed of course at the front portion of the grate as the rear portion of the
same is prevented or protected by the higher mass of the aforesaid glowing coal
and also by the fire-bridge bbbbb from receiving any of the charge or coal.
Then when the fire-door is closed, the following takes place:
pon the front portion of the grate a la coking will take place, for the reason
that the gases generated or developing from the cold fuel, are, as is clear, not hot
enough to be at once ignited. These gases are forced to pass partly over and
partly under the glowing fire-bridge bb¹ b² b'b and to come in contact with the
glowing coal-mass at i¹.
The decrease of the extent over which the cold gases would otherwise spread,
(which decrease as mentioned takes place at the fire-bridge bbbbb, and at the
glowing coal pile at ¹) causes the cold gases to become heated, and mixed with
the ascending gases, whereupon the said cold gases ignite in the space p, if they
have not already ignited in the flues or chambers and p².
C
In any case it is certain that before the said gases reach the before mentioned
rear wall c which is also highly heated, they must be ignited, for the reason that
into the mixing space p enter not only hot gases emitted from but also the
gases which have reached the grate a².
Upon this grate-portion a² rests of course only a thin layer of coal, and further-
more only a small air-supply enters through the apertures a³. Thus between
or from this portion of the grate very hot and perfectly ignited gases are
emitted, which mix with the cold gases of the front grate-portion, and which
at the said wall or contraction e must without doubt ignite and be completely
burnt. As an important feature of this present invention I regard on the one
hand the fire-bridge b b¹ b² b¹b, arranged as above indicated in the form of a strut

page_text: frame-like erection, whereby the same is capable of resisting every tendency to
bend. This is necessary as the fireclay blocks of the said structure c are always
in the region of the hottest fire-gases.
It is also regarded as new that the rear grate-portion a² receives a limited
air-supply, in consequence of the parting-walls (provided with the beforesaid
openings a³) only permitting access of a small amount of air to this portion of the
grate, whereby I attain the following:
Upon this grate-portion a², as before stated, only the smallest layer of coal
rests, as the stoker cannot with any degree of certainty push the glowing-coal to
the rear part of the grate, without the risk of its falling behind the separating-wall s
If this said grate portion a² received a powerful air-supply, the said thin coal-layer.
upon a would not only quickly burn through, but such greater supply of air would
cause too strong a draught through the grate-portions a a¹ (for each of which parts a a¹
the fire-bridge bb1b2b hinders the influence of the stack or chimney), thus.
a stagnation would take place in the supply of air, the coal would not be consumed
in sufficient quantity, the grate-bars would not be cooled in suitable manner,
and furthermore sufficient development of steam would not take place, nor
would the grate be protected from burning. It will be thus clear, that this
limitation of the supply of air to the rear part a² is one of the most important
and characteristic features of the present invention, together or in combination
with the aforesaid strut frame-like structure of the fire-bridge.
Such limitations of the air supply as shown at c, have, it is true, been hitherto
employed for a smooth grate, where a fire-bridge of no special height was
erected behind the grate, but such part was not hitherto arranged for the supply
of air to such grate-portion or in other words such contraction e had not been
constructed for the "supply" of air to the portion a² of the grate, but hitherto
the "discharging" gases from this said grate portion had been throttled. This
latter system is not however so advantageous, as it is not thereby possible during
the throttling or contraction, to regulate the same. This regulation in the present
invention can be easily effected by closing one or more of the apertures a³, for
which reason the arrangement of the contraction or throttling of the air-supply
to the rear-portion of the fire-grate, as herein described and forming, as above
mentioned, a feature of my present invention, is preferable to the methods hitherto
known for this purpose.
Whilst the construction represented in Figures 1 and 2 is intended for land-
boilers, the arrangement in Figures, 3 and 4 is adapted for marine-boilers. The
latter differs only from the first mentioned, in that the contracting-wall c or the
device for throttling the gases which according to the arrangement of Figure 1
is located at the bottom of the flue, is here (Figures 3 and 4) arranged in the
form of an arch in the flue. The gases passing over the fire-distributing
bridge bb bb, as also underneath the same, are led downwards throughout the
arched structure or bridge c¹ and are thereby caused to mix more intimately with
the hot gases coming from a³. Of course this same method of contraction or
throttling of the gases may also be employed for land-boilers. The chief points
are the especial arrangement of the boiler and the supply of air.
In Figure 5 another modification of this arrangement is represented, in which
both the before mentioned strut-like frame structure can consist of two parts.
and also the contracting or throttling device of the rear part of the grate is
movably arranged, this device is movable in a horizontal direction, so that on the
one part the throttling member or damper s when moved or adjusted horizontally
by means of the bent lever which serves as a push and pull rod, in the manner
indicated by the drawing Figures 5 and 6, causes a larger portion of the back
end of the grate to form a burning grate proper, upon which the throttling of the
air-supply acts. The throttling can further be achieved by reducing the air-space
between the grate, by moving the dampers in a vertical direction by means of
the lever aforesaid, its bend forming its fulcrum, so that as desired, more or less
air can be conducted to the rear portion of the grate.

page_text: The arrangement of the throttling device in the modified form, as above
mentioned, is shown in Figure 5 moved horizontally to the rear and the damper
is in its lowest position.
Figure 6 shows the same air-throttling devices in its highest position and
furthermore in its most extended or forward position, this position indicated by
the letters no causing the rear part of the grate to correspond to that part of
the grate marked, a in Figure 1, for which said rear grate portion the air-supply
is throttled in the manner above described.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is —
1. In á furnace, the combination with a grate of a fire-bridge located above the
rear portion thereof, and an adjustable air throttling device located under the
grate and adapted to regulate the supply of air to the grate and adapted to regulate
the supply of air to the rear portions of the grate, for the purpose as described.
2. The constructions of furnaces substantially as described and shown.
May 100.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.