Improvements in and connected with Smoke-consuming Furnaces.
Year: 1896

page_text: Improvements in and connected with Smoke-consuming Furnaces.
1, ROBERT DEISSLER of 2, Elsen Strasse of Treptow near Berlin, in the
Kingdom of Prussia, German Empire, Civil Engineer, do hereby declare the
nature of this invention to be as follows:-
This invention refers to furnaces of that kind in which a fire-beam arranged at
some distance above the grate divides the latter, or rather the burning fuel laying
thereon, into two parts, one of which (the front part) serves for the generation of
gas out of the coal, whereas the other serves for the direct combustion of the
remaining coke. My improvements in furnaces of said kind relate to means for
doing away with a variety of drawbacks that have adhered to said furnaces up to
now, and the most essential of which are as follows:
Those parts of the grate that are situated in front of the fire-beam, and in close
proximity to the same, are burnt in a short time, as in consequence of the projecting
of the fire-bridge over the grate, and of the thick layer of the coal at the front
edge of the fire-beam, a sufficient quantity of air cannot find access to the grate
from below the same. The rear portion of the grate can but difficultly be charged,
and the stoker cannot judge as to whether or not said portion is properly furnished
with coal; moreover, said rear portion of the grate is very easily obstructed by
slag, and it is a matter of utmest difficulty to get said portion cleansed.
In order to overcome the aforementioned drawbacks, I provide means for
throttling the gases that stream forth from the rear portion of the grate; I prefer
to employ as such a means a second fire-beam, and, may be, also a second fire-bridge,
and in some cases I prefer to reduce the first or ordinary fire-bridge in height as
far as to have the top-surface of the latter lie flush with the grate, as is all fully
described hereinafter. The leading principle of my invention is to cause the air to
pass through the front or main-portion of the grate, or rather through the thick
layer of coal laying thereon, in about the same relative quantity, or with about the
same velocity, as is the case with regard to the rear portion of that grate, and I
attain that object (as has already been mentioned) by throttling the gases
that stream forth from the thoroughly burning coal laying upon said latter
portion.
In order to make my invention more clear, I refer to the accompanying drawings,
in which similar letters denote similar parts throughout the different views, and in
which:-
Figure 1 Sheet 1 is a vertical longitudinal section through the front portion of a
flame tube of a Cornish- Lancashire-, or Galloway-boiler;
Figure 2 is a horizontal section of Fig. 1 the grate-bars being removed;
Figure 3 is a view similar to Fig. 1, but showing a slightly modified form of
construction,
Figure 4 Sheet 2 is a vertical longitudinal section through the furnace of a
tubulous boiler;
Figure 5 is a vertical cross-section in liue 9-10 of Figure 4; and
Figure 6 is an inclined section in line 11-12 of Figure 5, showing but the left-
hand portion of the furnace.
Referring to Figs. 1 & 2, a¹ b¹ designate the front and the rear portion of the

page_text: grate, and d the fire-beam, which is situated in a height of about 160 m/m above
said rear portion, as well as above the fire-bridgee. The latter is reduced in height
as far as to have its top surface lie flush with the grate.
Another fire-bridge is arranged behind the first-mentioned fire-bridge e in a
distance of about 300 m/m from the latter; said second bridge extends up into the
proximity of the fire-bcam d, and leaves, or forms, a small channel between
itself and said fire-beam.
The latter is supported at its sides or ends by suitable stones h resting upon the
fire-bridge e; this bridge as well as the second bridge is provided with bottom-
channels e¹, or j¹ respectively.
The fire-beam d extends horizontally for a somewhat long way over the bridge e,
as well as over the rear portion b¹ of the grate; owing to the size and arrangement
of said beam, and to the combination and co-operation of the same with the second
bridge f, the gases streaming forth from the coal that is present within the space
formed by the parts d, e, and h, are throttled; and by suitably proportioning the
dimensions of the several co-acting parts, said gases may be throttled in such a
degree, that the draught for the large front portion a¹ of the grate is practically as
strong as that for the small rear portion 61 of the same.
It may on first view seem strange that the two fire-bridges e and fare separated
one from the other. This is, however, indispensably requisite, because, a space for
the reception of the slag (from the rear portion of the grate) must be provided.
The slag forming upon said portion must be pushed rearwards and down (into said
space or reservoir) from above the grate, as otherwise the said portion cannot be
preserved in proper condition. The channels e¹ of the bridges e fare provided
with doors e 2 2.
I am well aware that two fire-bridges arranged one behind the other have already
been used in a furnace; but then that arrangement was intended to permit of fresh
air entering the furnace behind the grate (between said two fire-bridges). This is
essentially different from what I do, in that I first, form by the second bridge a
reservoir for the reception of the slag (as just described), and, second, employ said
second bridge for the formation of a channel, that is adapted to throttle the gases
streaming forth from the rear portion of the grate.
The top surface of the second bridge lies below the plane of the top-surface of
the fire-beam d; I prefer to let said second bridge have the normal height of
ordinary fire-bridges, and by doing so I gain or regain for the whole grate the
ordinary or normal conditions of draught.
The great horizontal extent of the fire-beam d to the front as well as to the rear
(about the rear edge of the fire-bridge e) affords the further advantage that the
grate proper is but little exposed to the weight of said beam. The supporting side-
stones may partly rest upon the grate, but this will in general be unnecessary,
as the projecting front-portion of the beam d may well be balanced by the
projecting rear-portion of the same.
Another advantage offered by the great horizontal extent of the beam d resides
in the following:
The smoke emanating from the front-portion a' of the grate (after the latter has
been freshly charged) is compelled to wash the large surface of the intensely heated
fire-beam, and is thus itself intensely heated which greatly facilitates or promotes
the subsequent combustion of the same. Further, the beam need take but over a
small portion of the grate proper, as the fire-bridge e by reason of its being reduced
in height (as described) forms itself a sort of grate, although without spaces. The
rear portion b¹ of the grate can thus be easily cleansed.
The coal forms a slope from the front edge of the fire-beam d to the rear
end of the fire-bridge e; the air passing (in excess) through and over this portion
of the fuel is compelled to flow along the lower surface of the beam, and is
thereby intensely heated. The mixture of hot fire-gases and hot air passes
through the channel g into the way of the smoke streaming forth from the
space above the beam d, and mixes with said smoke. The latter has also been

page_text: intensely heated by said beam, and is now practically completely burnt or
consumed.
As soon as the fire is burnt down, or requires fresh charging respectively,
there is first the portion 61 of the grate cleansed from slag by pushing the latter
over the fire-bridge e down into the reservoir c. The remaining coal which is
thoroughly burning or intensely glowing is then shoved upon the portion b¹ of
the grate, in such a manner, that it forms again a slope commencing at the front
edge of the fire-beam d and terminating near to the rear-edge of the bridge e.
A part of the remaining coal is distributed over the front portion al of the
grate, and said portion is then charged with the fresh coal. The smoke that is
instantly or very shortly thereafter evolved by the fresh coal is intensely heated
by the beam d, and is then burnt or consumed, as has already been described.
The gases coming from the grate-portion & are able to effect said smoke-less
combustion because the air flowing from below into and through said portion is in
excess, and has been very intensely heated by the thoroughly burning coal of the
said portion b. The mixture of the fire-gases and of the excess of the air is kept
in its heated state by the rearwardly extending beam d, and the heat as well as
the air or oxygen of said mixture are fully sufficient to cause the ignition and the
combustion of the smoke.
In the modification shown in Fig. 3 the second fire-bridge f is als bat low, or
reduced in height respectively, and carries also a fire-beam (d). The latter
extends horizontally for rather a long way, very nearly so as has been described
with regard to the first or front fire-beam d, and there is also left a channel g
between the beams d and d'. The beam d', however, is supported by the fire-
bridge not throughout the whole breadth of the same, but there is or are left a
channel or channels g! that also forms or form a way or ways for the fire-gases
streaming forth from the rear portion of the grate. Said gases are, it is true,
throttled in this case not in the same degree, as occurs in the construction shown
in Fig. 1, but the degree of their throttling is a sufficient one for the purpose
intended. The throttling action to which the lower stream or streams of the fire-
gases are exposed, is due not only to the narrowness of the channel or channels b¹,
but also to the friction arising at the lower surface of the beam d'.
The arrangements described up to now are especially adapted for use with
Cornwall, Lancashire-, Galloway- and similar boilers, but if suitably modified they
may also with other types of boilers be advantageously employed.
I have shown such a modification in Figs. 4, 5 & 6 of the drawing. The main
difference resides in the particular position of the fire-beam proper d 2, in that this
latter extends not across the rear-portion of the grate, but parallel to the bars of
the same. In this case I prefer to make use of two of such lateral fire-beams,
as shown in Fig. 5. That portion of the fresh coal, which is to cover the
rear half of the grate, is filled up between the two fire-beams d2 d 2, after the
burning coal that was present upon said half of the grate has been shoved to
the left and to the right, so as to form two slopes (compare Fig. 5).
I prefer to combine the fire-beam proper d'2 with another fire-beam d 3 that is
arranged above said beam d 2, and forms between itself and said beam a small
channel 92, by means of which the gases coming from the lateral chambers of the
grate or furnace are throttled. The air entering the grate from below passes
through the two lateral chambers as well as through the central main chamber
(containing the fresh coa!). Owing to the throttling action of the channel g 2
the air is hindered to flow in too great a quantity through the lateral chamber or
chambers (formed by the fire-beams d2 d'3, and the adjacent portion of the wall
of the furnace), and the grate portion lying helow the central chamber receives
thus sufficient air to be prevented against being burnt.
There may be one or two of said fire-beams d2, and oue or two of said fire-
beams d3 in a furnace; in either case said fire-beains or pairs of fire-beams need
not extend over the whole length or depth of the grate, but need extend only
over the rear half or rear portion of the same (compare Figs. 4 & 6). The

page_text: front ends of the fire-beams d 2 may be supported by stones k of any suitable
configuration.
I prefer to provide within the furnace-walls two inclined channels c¹ situated in
close proximity to the side portions of the grate, or to the chambers containing
the slopes of thoroughly burning coal respectively. Said channels c' are intended
to receive the slag removed from said side-portions of the grate.
Dated this 4th day of April 1896
ROBERT DEISSLER,
By Geo. Thos. Hyde,
1, Broad Street Buildings, London, E.C., Agent for the Applicant.
Improvements in and connected with Smoke-consuming Furnaces.
I, ROBERT DEISSLER, of 2, Elsen Strasse, of Treptow, near Berlin, in the
Kingdom of Prussia, German Empire, Civil 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 refers to furnaces of the kind in which a fire-heam arranged in
some distance above the grate divides this latter, or rather the burning fuel laying
thereon, into two parts, one of which (the front part) serves for the generation of
gas out of the coal, whereas the other serves for the. direct combustion of the
remaining coke. My improvements in furnaces of said kind relate to means for
doing away with a variety of drawbacks that have adhered to said furnaces up to
now, and the most essential of which are as follows:
Those parts of the grate that are situated in front of the fire-beam, and in
close proximity to the same, are burnt in a short time, as in consequence of the
projecting of the fire-bridge over the grate, and of the thick layer of the coal at
the front edge of the fire-beam, a sufficient quantity of air cannot find access to
the grate from below the same. The rear portion of the grate can but difficultly
be charged, and the stoker cannot judge as to whether or not said portion is
properly furnished with coal; moreover, said rear portion of the grate is very
easily obstructed by slag, and it is a matter of utmost difficulty to get said portion
cleansed.
In order to overcome the aforementioned drawbacks, I provide means for
throttling the gases that stream forth from the rear portion of the grate; I prefer
to employ as such a means a second fire-beam, and, may be, also a second fire-bridge,
and in some cases I prefer to reduce the first or ordinary fire-bridge in height as
far as to have the top-surface of the latter lie flush with the grate, as is all fully
described hereinafter. The leading principle of my invention is to cause the air to
pass through the front- or main-portion of the grate, or rather through the thick
layer of coal laying thereon, in about the same relative quantity, or with about the
same velocity, as is the case with regard to the rear portion of that grate, and I
attain that object (as has already been mentioned) by throttling the gases that
stream forth from the thoroughly burning coal laying upon said latter portion.
In order to make my invention more clear, I refer to the drawings sent in with
Provisional Application, in which similar letters denote similar parts throughout the
different views, and in which:-
Figure is a vertical longitudinal section through the front portion of a flame
tube of a Cornwall-, Lancashire-, or Galloway-boiler;
Figure 2 is a horizontal section of Figure 1, the grate-bars being left away;

page_text: Figure 3 is a view similar to Figure 1, but showing a slightly modified form of
construction,
Figure 4 is a vertical longitudinal section through the furnace of a tubulous.
boiler;
Figure 5 is a vertical cross-section in line 9-10 of Figure 4; and
Figure 6 is an inclined section in line 11-12 of Figure 5, showing but the
lefthand portion of the furnace.
Referring to Figures 1 & 2, a¹ b¹ designate the front and the rear portion of the
grate, and d the fire-beam, which is situated in a height of above 160 m/m above
said rear-portion, as well as about the fire-bridge e. The latter is reduced in
height as far as to have its top-surface lie flush with the grate.
Another fire-bridge is arranged behind the first-mentioned fire-bridge e in a
distance of about 300 m/m from the latter; said second bridge extends up into the
proximity of the fire-beam d, and leaves, or forms, a small channel g between itself
and said fire-beam.
The latter is supported at its sides or ends by suitable stones h resting upon the
fire-bridge e; this bridge as well as the second bridge is provided with bottom-
channels e', or f', respectively.
The fire-beam d extends horizontally for a somewhat long way over the bridge e,.
as well as over the rear portion b' of the grate; owing to this size and arrangement
of said beam, and to the combination and co-operation of the same with the second
bridge, the gases streaming forth from the coal that is present within the space
formed by the parts d, e and h are throttled; and by suitably proportioning the
dimensions of the several co-acting parts, said gases may be throttled in such a
degree, that the draught for the large front portion a¹ of the grate is practically as
strong as that for the small rear portion of the same.
It may on first view seem strange that the two fire-bridges e and fare separated
one from the other. This is, however, indispensably requisite, because a space for
the reception of the slag (from the rear portion of the grate) must be provided.
The slag forming upon said portion must be pushed rearwards and down (into said
space or reservoir) from above the grate, as otherwise the said portion cannot be
preserved in proper condition. The channels el f¹ of the bridges ef are provided
with doors e 2 f2.
I am well aware that two fire bridges arranged one behind the other have already
been used in a furnace; but then that arrangement was intended to permit of fresh
air entering the furnace behind the grate (between said two fire-bridges). This is
essentially different from what I do, in that 1, first, form by the second bridge a
reservoir for the reception of the slag (as just described), and, second, employ said
second bridge for the formation of a channel that is adapted to throttle the gases
streaming forth from the rear portion of the grate.
The top surface of the second bridge lies below the plane of the top-surface of
the fire-beam d; I prefer to let said second bridge have the normal height of
ordinary fire-bridges, and by doing so I gain or regain for the whole grate the
ordinary or normal conditions of draught.
"
The great horizontal extent of the fire-beam d to the front as well as to the rear
(about the rear edge of the fire-bridge e) affords the further advantage that the
grate proper is but little exposed to the weight of said beam. The supporting
side-stones may partly rest upon the grate, but this will in general be unnecessary,
as the projecting front-portion of the beam d may well be balanced by the
projecting rear-portion of the same.
Another advantage offered by the great horizontal extent of the beam d resides
in the following: The smoke emanating from the front-portion a¹ of the grate
(after the latter bas been freshly charged) is compelled to wash the large surface
of the intensely heated fire-beam, and is thus itself intensely heated which greatly
facilitates or promotes the subsequent combustion of the same. Further, the beam
need take but over a small portion of the grate proper, as the fire-bridge e by
reason of its being reduced in height (as described) forms itself a sort of grate,

page_text: although without spaces. The rear portion b¹ of the grate can thus be easily
cleansed.
The coal forms a slope from the front edge of the fire-beam d to the rear end of
the fire-bridge e; the air passing (in excess) through and over this portion of the
fuel is compelled to flow along the lower surface of the beam, and is thereby
intensely heated. The mixture of hot fire-gases and hot air passes through the
channel g into the way of the smoke streaming forth from the spare above the
beam d, and mixes with said smoke. The latter has also been intensely heated by
said beam, and is now practically completely burnt or consumed.
As soon as the fire is burnt down, or requires fresh charging respectively, there
is first the portion & of the grate cleansed from slag by pushing the latter over the
fire-bridge e down into the reservoir c. The remaining coal which is thoroughly
burning or intensely glowing is then shoved upon the portion of the grate, in
such a manner, that it forms again a slope commencing at the front edge of the
fire-beam d and terminating near to the rear-edge of the bridge e. A part of the
remaining coal is distributed over the front portion a' of the grate, and said portion
is then charged with the fresh coal. The smoke that is instantly or very shortly
thereafter evolved by the fresh coal is intensely heated by the beam d, and is then
burnt or consumed, as has already been described.
The gases coming from the grate-portion & are able to effect suid smokeless
combustion because the air flowing from below into and through said portion is in
excess, and has been very intensely heated by the thoroughly burning coal of the
said portion b. The nixture of the fire-gases and of the excess of the air is kept
in its heated state by the rearwardly extending beam d, and the heat as well as the
air or oxygen of said mixture are fully sufficient to cause the ignition and the
combustion of the smoke.
In the modification shown in Figure 3 the second fire-bridge is also but low,
or reduced in height respectively, and carries aiso a fire-beam (d). The latter
extends horizontally for rather a long way, very nearly so as has been described
with regard to the first or front fire-beam d, and there is also left a channel g
between the beams d and d'. The beam d, however, is supported by the fire-
bridge not throughout the whole breadth of the same, but there is or are left a
channel or channels gl that also forms or form a way or ways for the fire-gases
streaming forth from the rear portion of the grate. Said gases are, it is true,
throttled in this case not in the same degree, as occurs in the construction shown in
Figure 1, but the degree of their throttling is a sufficient one for the purpose
intended. The throttling action to which the lower stream or streams of the
fire-gases are exposed, is due not only to the narrowness of the channel or
channels &', but also to the friction arising at the lower surface of the
beam d².
The arrangements described up to now are especially adapted for use with
Cornwall, Lancashire-, Galloway- and similar boilers, but if suitably modified they
may also with other types of boilers be advantageously employed.
I have shown such a modification in Figures 4, 5 & 6 of the drawing. The
main difference resides in the particular position of the fire-beam proper d 2, in that
this latter extends not across the rear-portion of the grate, but parallely to the bars
of the same. In this case I prefer to make use of two of such lateral fire-beams,
as shown in Figure 5. That portion of the fresh coal, which is to cover the rear
half of the grate, is filled up between the two fire-beams d2 d2; after the burning
coal that was present upon said half of the grate has been shoved to the left and
to the right, so as to form two slopes (compare Fig. 5).
I prefer to combine the fire-beam proper d 2 with another fire-beam d3 that is
arranged above said beam d 2, and forms between itself and said beam a small
channel 92, by means of which the gases coming from the lateral chambers of the
grate or furnace are throttled. The air entering the grate from below passes
through the two lateral chambers as well as through the central main chamber
(containing the fresh coal). Owing to the throttling action of the channel g2 the

page_text: air is hindered to flow in too great a quantity through the lateral chamber or
chambers (formed by the fire-beams d 2 d3, and the adjacent portion of the wall of
the furnace) and the grate portion lying below the central chamber receives thus
sufficient air to be prevented against being burnt.
There may be one or two of said fire-beams d 2, and one or two of said fire-
beams d 3 in a furnace; and in either case said fire-beams or pairs of fire-beams
need not extend over the whole length or depth of the grate, but need extend only
over the rear half or rear portion of the same (compare Figures 4 & 6). The
front ends of the fire-beams d2 may be supported by stones k of any suitable
configuration.
I prefer to provide within the furnace-walls two inclined channels c' situated in
close proximity to the side portions of the grate, or to the chambers containing the
slopes of thoroughly burning coal respectively. Said channels c¹ are intended to
receive the slag removed from said side-portions of the grate.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what [
claim is :-
1. In a furnace having a reduced fire-bridge, and a fire-beam extending in some
distance over said bridge and over the rear portion of the grate, the combination
with the said bridge, of another fire-bridge arranged in some distance behind the
foriner, and extending up to about the height of said fire-beam, and forming
between itself and said beam a channel the free section of which is smaller
than the free section of the space existing between the fire-beam, the first-
mentioned fire-bridge, and the adjacent portions of the walls of the furnace, for
the purpose as described.
2. In a furnace having a reduced fire-bridge and a fire-beam extending in some
distance over said bridge and over the rear portion of the grate, the combination
with the said bridge, of another bridge arranged in some distance behind the former,
and of another fire-beam supported by said other bridge, and forming between
itself and the first-mentioned beam a channel the free section of which is smaller
than the section of the space existing between said first-mentioned beam, the first-
mentioned fire-bridge, and the adjacent portions of the walls of the furnace, for
the purpose as described.
3. In a furnace having a reduced fire-bridge, and a fire-beam extending in some
distance over said bridge and over the rear portion of the grate, the combination
with said bridge, of another fire-bridge arranged in some distance behind the
former, and of another fire-beam arranged in some distance over said other bridge,
and forming between itself and the latter as well as between itself and the first-
mentioned fire-beam channels the combined free sections of which are smaller than
the free section of the space existing between said first-mentioned beam, the first-
mentioned fire-bridge and the adjacent portions of the walls of the furnace, for
the purpose
described.
4. In a furnace having a fire-beam arranged in front of the fire-bridge, and
extending in some distance over the grate, the combination with said beam and said
bridge, of another fire-beam supported by the said bridge and arranged in some
distance over the first mentioned fire-beam, and forming between itself and the
latter a channel the free section of which is smaller than the space of the free
section existing between said first-mentioned beam, the said bridge, and the adjacent
and opposite portions of the wall of the furnace, for the purpose as described.
Dated this 19th day of December 1896.
ROBERT DEISSLER,
By Geo. Thos. Hyde,
1 Broad Street Buildings, Liverpool Street, London, E.C.,
Agent for the Applicant.