improvements in or connected with Furnaces.
Year: 1894

page_text: Date of Application, 20th Sept., 1894
Complete Specification Left, 17th July, 1895-Accepted, 17th Aug., 1895
improvements in or connected with Furnaces.
We, JAMES JONES MELDRUM, THOMAS FREDERICK MELDRUM, and JOHN
WESLEY MELDRUM, all of Atlantic Works, City Road, Manchester, in the
County of Lancaster, Engineers, do hereby declare the nature of this invention to
be as follows:
-
This invention has reference to furnaces for burning combustible material or
material partially combustible, as furnaces for destroying towns' refuse, furnares
of certain metallurgical apparatus, furnaces of certain kinds of steam generators,
and the like.
According to this invention, a furnace has two, three, or more beds or fire-places,
practically separate, on which the material is burned, the several individual beds or
fire-places being separately worked--that is, stoked, fed, cleaned, etcetera-through
suitable doorways or apertures at the side of the furnace, or through separate
hoppers and doors. The flames and combustion gases from all the separate
beds or fire places travel in the same direction, either from left to right
or from right to left when facing the fire or other like doors: in other words,
the fire gases travel sideways passing from the first grate over fires No. 2,
or 2, 3, 4, etc. as the case may be, from the second fire over 3, 4, etc.; and
from the third fire over 4 etc. Thus all the gases of the different fire-places
are caused to mingle together before leaving the last fire-places of the series,
whilst the different fire-places should be worked at different times, as in series,
or rotation. The fires being worked in series, and at proper intervals, fuel or
material on one or more of the fire-places will be in a state of full combustion
at all times, and thus when new fuel or material is fed or worked onto the different
fire-places, the gases given off therefrom will become mixed with the flames and
gases from the others, with the result that complete combustion is promoted, and
the formation of smoke prevented: if fires are cleaned and fed in series at even
intervals, say with four fires, one fire every five minutes, and each fire once in the
hour, the prevention of smoke will be best accomplished; and at the same time
the final temperature of the gases as they pass away from the furnace will be fairly
constant.
The number of separate grates or fires will vary according to circumstances:
three or four are convenient numbers, though more or less (viz. two) may be
employed, the general nature of the construction being to subdivide the furnace
crosswise, that is at right angles to its length, each portion being separately fed
with fuel and air, and separately cleaned, so that an approximately constant average
temperature is maintained.
In towns' refuse destructors, and some metallurgical, and analogous furnaces, a
roof of fire-brick or equivalent material will in most cases be used above the fire
places; whilst in cases, such as in externally or under fired steam generators, part
of the steam generator could be disposed above the fireplaces.
One special construction of furnace according to this invention will consist of a
brick or brick lined chamber with two or more fire-places, the direction of lengths
of which run transversely to the direction of length of the whole furnace, and the
flow of gases therein; each having a fire door at one end (or both ends) of same
in the side wall or walls of the furnace. The ashpits of the fireplaces are separated
by partitions or walls, and these walls in some cases may be carried up above
the level of the bed on which the material rests, so making divisions above as well

page_text: as below same.
In the case of the grates consisting of firebars, with spaces between
them, such bars would preferably lie or run in line or parallel with the length of the
fire-places. The gases and flames therefore of the fire-place or fire-places in front
of the last of the series constituting the furnace, would all pass over the last and
become mixed, with the effects above specified.
In some cases it may be preferable to make the several grates join up to
each other without any dead plates or wall to separate them, the ashpits only being
divided.
In furnaces of this type we sometimes use dead plates or wide bars at the sides
of the fire-places, or at the sides and ends, by which the fierceness of the fires
at these parts is modified, and very high temperatures kept away from the walls,
and thereby preventing their rapid destruction; and where division walls between
the fire-places above the grates are not used, similar dead plates or side bars may
be employed to divide the fire places and material or fuel thereon, so that in the
different fire-places, the material or fuel can be worked without disturbing the
material or fuel on the adjacent fire-place or fire-places. These dead plates may
be used in other brick furnaces for protecting the wall. In the case of water tube
grates with some of the tubes carried up at the sides, these dead plates or side bars
will of course be unnecessary.
The material or fuel to be burned may be fed to the fire places through fire
doors, or in some cases through hoppers over the furnace crown; and it may be fed
mechanically from one end of each fire-place to the other, a cleaning door being
provided at the latter end.
The supply of air to the fires may be effected by natural means, as by a draught
caused by a chimney; or by artificial means, as by steam jet exhausting, or air
forcing apparatus, or other artificial means.
By
In the case of destructors for destroying towns' refuse, or like offensive material,
or material difficult of combustion, we, in some cases, provide a series of baffle
plates or walls or pillars beyond the last fire-place or bridge, which will be kept at
a high temperature, as a white or red heat, by the products of combustion.
these, and by mixing up the gases at the high temperature, the final combustion
of all fumes or offensive gases, that may have previously escaped destruction, will
be ensured.
In the cases of destructors, or other cases where the furnace is not primarily
intended for the generation of steam, the waste gases may be used for raising steam
for working the furnace.
In some cases the waste heat from the furnace is used to regenerate the air supply,
the fire bars being of solid metal as usual, or hollow, with water circulating through
them.
ני ד
1
We, JAMES JONES MELDRUM, THOMAS FREDERICK MELDRUM, and JOHN
WESLEY MELDRUM, all of Atlantic Works, City Road, Manchester, in the
County of Lancaster, Engineers, 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 has reference to furnaces for burning combustible material, or
material partially combustible, as furnaces for destroying towns refuse, furnaces of

page_text: certain metallurgical apparatus, furnaces of certain kinds of steam generators,
and the like.
According to this invention, a furnace has two, three, or more beds, or fire-
places, practically separate, on which the material is burned, the several
individual beds or fire-places being separately worked-that is, stoked, fed, cleaned,
et cetera, through suitable doorways or apertures at the side of the furnace, or
through separate hoppers and doors. The flames and combustion gases from all
the separate beds or fire places travel in the same direction, either from left to
right, or from right to left, when facing the fire or other like doors: in other
words, the fire gases travel sideways, passing from the first grate over fires No. 2,
or 2, 3, 4, etc. as the case may be, from the second fire over 3, 4, etc.; and from
the third fire over 4 etc. Thus all the gases of the different fire-places are caused
to mingle together before leaving the last fire-place of the series, whilst the
different fire-places should be worked at different times, as in series, or rotation.
The fires being worked in series, and at proper intervals, fuel or material on one
or more of the fire-places will be in a state of full combustion at all times, and thus
when new fuel or material is fed or worked onto the different fire-places, the gases
given off therefrom will become mixed with the flames and gases from the others,
with the result that complete combustion is promoted, and the formation of smoke
prevented if fires are cleaned and fed in a series at even intervals, say with
four fires, one fire every 15 minutes, and each fire once in the hour, the prevention
of smoke will be best accomplished; and at the same time the final temperature
of the gases as they pass away from the furnace will be fairly constant.
:
The number of separate grates or fires will vary according to circumstances:
three or four are convenient numbers, though more or less (viz. two) may be
employed, the general nature of the construction being to subdivide the furnace
crosswise, that is at right angles to its length, each portion being separately fed
with fuel and air, and separately cleaned, so that an approximately constant
average temperature is maintained.
In towns' refuse destructors, and some metallurgical, and analogous furnaces, a
root of fire-brick or equivalent material will in most cases be used above the fire
places; whilst in cases, such as in externally or under fired steam generators, part
of the steam generator could be disposed above the fireplaces.
One special construction of furnace according to this invention will consist of a
brick or brick lined chamber with two or more fire-places, the direction of lengths
of which runs transversely to the direction of length of the whole furnace, and
the flow of gases therein; each having a fire door at one end (or both ends) of
same in the side wall or walls of the furnace. The ashpits of the fire places are
separated by partitions or walls, and these walls in some cases may be carried up
above the level of the bed on which the material rests, so making divisions above
as well as below same. In the case of the grates consisting of firebars, with spaces
between them, such bars would preferably lie or run in line or parallel with the
length of the fire-places. The gases and flames therefore of the fire-place or
fire-places, in front of the last of the series constituting the furnace, would all
pass over the last and become mixed, with the effects above specified.
In some cases it may be preferable to make the several grates join up to each
other without any dead plates or wall to separate them, the ashpits only being
divided.
In furnaces of this type we sometimes use dead plates or wide bars at the sides
of the fire-places, or at the sides and ends, by which the fierceness of the fires at
these parts is modified, and very high temperatures kept away from the walls, and
thereby preventing their rapid destruction; and where division walls between the
fire-places above the grates are not used, similar dead plates or side bars may be
employed to divide the fire places and material or fuel thereon, so that in the
different fire-places, the material or fuel can be worked without disturbing the
material or fuel on the adjacent fire-place or fire-places. In the case of water tube

page_text: grates with some of the tubes carried up at the sides, these dead plates or side bars
will of course be unnecessary.
The material or fuel to be burned may be fed to the fire-places through fire
doors, or in some cases through hoppers over the furnace crown; and it may be fed
mechanically from one end of each fire-place to the other, a cleaning door being
provided at the latter end.
The supply of air to the fires is preferably effected by artificial means,
as by steam jet air forcing apparatus, or other artificial means.
In the case of destructors for destroying towns refuse, or like offensive
material, or material difficult of combustion, we, in some cases, provide a series of
baffle plates or walls or pillars beyond the last fire-place or bridge, which will be
kept at a high temperature, as a white or red heat, by the products of
combustion. By these, and by mixing up the gases at the high temperature, the
final combustion of all fumes or offensive gases, that may have previously escaped
destruction, will be ensured.
In the case of destructors, or other cases, where the furnace is not primarily
intended for the generation of steam, the waste gases may be used for raising steam
for working the furnace.
In some cases the waste heat from the furnace is used to regenerate the air
supply, the fire bars being of solid metal as usual, or hollow with water
circulating through them.
Drawings illustrative of this invention are annexed hereto, and form part
thereof. Figure 1 in these drawings is a sectional plan illustrating the invention:
Figure 2 is a cross section at A A Figure 1; and Figure 3 is a front elevation.
Figures 4, 5, and 6 are sectional plans illustrating other modifications.
Referring in the first instance to Figures 1, 2, and 3, a¹, a², a³, a', are four fire
places, each having a grate, and a firing door bin the front wall c of the furnace.
d are dead plates between the different grates these grates being represented by
the close parallel lines, and d' are similar dead plates between the fire-bars and
the back wall c', and end wall c" of the furnace. e is a chamber and e' the brick-
work pillars beyond the last fire place or bridge, through and over which the gases
pass, and is a flue beyond this part, from which the gases are caused to pass, by
suitable valves or dampers, either to a chimney f¹ direct, or to a steam generator,
or partly to one, and partly to the other.
By the example given, it will be seen the direction of flow of gases is in a line
from the fireplaces towards the flue f, and that the fireplaces are in the line of
that flow, and that, therefore, the gases for each and all of the fire-places a¹, a²,
and a³, have necessarily to pass over the furnace a; and excepting a³, the gases
from the others will have to pass over two or more fireplaces, accordingly as they
are further removed in the series from a².
In the example shewn, the ashpits of the fire-places are separate, they being
divided by a partition wall n; and cach ashpit is provided with a door h, and
steam jet blowers i (say of "the Meldrum" type), placed horizontally under the
grate with their bodies lying practically wholly within the ashpit. By these
blowers air, to support combustion of the material, is supplied, and it is maintained
by them at a pressure above that of the atmosphere.
Doors e² are provided in the wall of the chamber e by which access is had to
such chamber, and the spaces between the columns cleared of the dust which may
accumulate there.
In action, the fires are fed, preferably, in series at even intervals, say one every
fifteen minutes, and each fire once in the hour. The gases leaving the furnaces
pass or flow along in the direction of the length of the destructor towards the
chamber e, those from all the fireplaces a', a², and a³, passing over a, those from a
over a³ and a, and those from a¹ over a², a³, and a; from the furnace proper comprising
these four fire-places, they pass over the bridge d, and enter the chamber e, and
pass over the brickwork pillars which are disposed in checker arrangement;

page_text: and then pass away through the outlet flue to the steam generator/2, or
chimney. By arranging the fires in this way, and working them in series as
described, one or more of the fires will be in a state of full combustion at all times;
and as the gases of all the different fire-places are caused to mingle together before
leaving the furnace, when new fuel or material is fed or worked onto any one of
them, the fresh or "green" gases given off therefrom will become mixed with the
flame and gases from another or others, resulting in the promotion of complete.
combustion and the prevention or formation of smoke. The gases passing over fron
the fire-places, and through the chamber e, and over its incandescent pillars e', rendered
incandescent by the heat of the furnace gases passing over them, become baffled or
diverted, and mixed up, and being at a high temperature, the final combustion of
all fumes or offensive gases that may previously have escaped destruction, is ensured.
In the destruction of the town's refuse or like material, these are particularly
valuable and useful.
As regards the pillars e', and their uses, these being constantly maintained at a
bright red or white heat, take the place of cremator furnaces commonly used in
combination with the primary destructor furnaces; and by them, in connection with
the fireplaces arranged as described, better results are obtained without such
cremator furnaces, than where cremator furnaces are used.
Referring now to the modifications shewn in Figures 4, 5, 6, 7, in Figure 4,
within the fireplaces between the doors for feeding or firing them, we provide
internally projecting walls or divisions k, for the purpose of keeping away the
intense heat of the furnace from the fireman when cleaning the fire. In this case,
in order to compensate for the area of flue for the flow of gases, which is taken off
by the introduction of these walls, a flue l, as shewn in Figure 5, is preferably
provided. Obviously, however, the required area of flue could be obtained by
raising the crown of the furnace; but since this would be inimical to the best
working and results, the modification by the addition of the flue is preferred. In
this case also, a bridge d² would be provided at the ends of the furnaces, as well as
at the side of the last furnace a'.
As regards this flue 1, it may also be used with advantage in other cases when
the roof is low, or near the grate surface; or where an unusually large number of
fire-places is placed side by side, as in such a case the combined volumes of gases
from the fireplaces will require a greater area for their free passage.
In the modification shewn in Figure 6, the fireplaces of furnaces under this
invention are arranged in duplex sets, back to back, the division walls of the
ashpits being indicated by the dotted lines marked n. Otherwise than in this
respect, it is similar, in effect, to the arrangement set forth with reference to
Figures 1 to 3.
Regarding the modification shewn in Figure 7, this shews the duplex arrange-
ment illustrated in Figure 6 provided with the flue 1, and with bridges d² set forth
with reference to Figure 5.
Suitable doors are provided for cleaning out all the dust from the whole of the
ashpits, flues, and chimney, so that the apparatus can be continuously used without
danger of any part becoming choked with flue dust.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
1. The improved furnace herein described, namely, a furnace for burning material
such as described, consisting of or comprising a plurality of fire places disposed in
the line of the direction of flow of the gases towards their outlet or point of
discharge, whereby the gases of one or more of the fireplaces pass over another or
others, and mix together, and each fireplace being provided with a door for attending
to the fire; and the ashpits of the said fireplaces being closed and separated, and
air, at a pressure greater than that of the atmosphere, introduced into them, and

page_text: employed to effect the combustion of the material on the fireplace grates; operating
substantially as and for the purposes specified.
2. A furnace for burning material such as described, comprising a plurality of
fire-places disposed in the line of the direction of the flow of the gases towards their
outlet, each fire place being provided with a door by means of which the fire is
attended to, and the ashpits of which are closed and separated, and adapted to be
supplied with air, for the combustion of the material on the grates, at a pressure
above that of the atmosphere, and having short walls or screens, such as k, between
the fire places; substantially as and for the purposes specified.
3. A furnace for burning material such as described, comprising a plurality of
fire-places disposed in the line of the direction of flow of the gases towards their
outlet, each fire-place being provided with a door by means of which the fire is
attended to, and the ashpits of which are closed and separated, and adapted to be
supplied with air, for the combustion of the material on the grates, at a pressure
above that of the atmosphere, and having a flue, such as 1; substantially as and
for the purposes described.
4. A furnace for burning material such as described, comprising a plurality of
fire-places disposed in the line of the direction of the flow of the gases towards their
outlet, each fire-place being provided with a door by means of which the fire is
attended to, and the ashpits of which are closed and separated, and adapted to be
supplied with air for the combustion of the material on the grates, at a pressure
above that of the atmosphere; and a chamber e with pillars e¹ through and over
which the said gases are caused to pass substantially as and for the purposes
described.
5. The furnace for combusting materials as specified, having parts arranged,
combined, and adapted to operate, particularly as set forth with reference to and as
shewn in Figures 1, 2, and 3.
6. The furnace for combusting materials as specified, having parts arranged and
adapted to operate particularly as set forth with reference to and as shewn in
Figure 4, Figure 5, Figure 6, and Figure 7, of the drawings.
Dated this 13th day of July 1895.
CHEESBROUGH & ROYSTON,
15 Water Street, Liverpool, Applicants' Patent Agents.