Improvements in Devices for Retaining Heat in Steam Boiler and other Flues.
Year: 1897

page_text: Date of Application, 17th Sept., 1897
Complete Specification Left, 16th July, 1898-Accepted, 17th Sept., 1898
Improvements in Devices for Retaining Heat in Steam Boiler and
other Flues.
I, GUILLAUME ARNAUD NUSSBAUM, of 29, Ludgate Hill, in the City of London
Engineer, do hereby declare the nature of this invention to be as follows:-
-
My invention has for object to increase considerably the output of boiler furnaces,
ovens, etc.
It consists in the filling of flues with metal wire gauze in such manner
that the hot gases coming from the furnace can freely circulate through the wire
gauze. Instead of using wire gauze I may also use bundles of wire, perforated metal
sheets & the like. The hot gases & air passing through the heated wire gauze
are intimately mixed & burn completely, thereby raising considerably the tempera-
ture in the flues. Consequently not only is the production of steam from a given
quantity of fuel considerably increased through the application of my system but
the smoke is also completely consumed. As the wire gauze acts as an accumulator
of heat it prevents the cooling down through opening the furnace door, the injection
of feed water etc. Any metal may be used for the wire gauze etc. My system may
also be used with advantage in stoves, ovens chimneys & the like, & may while
giving a much greater amount of useful heat, do away with the smoke nuisance.
My system may also be used with more or less success with every kind of fuel, coal,
peat, wood, gas, mineral oil etc.
Improvements in Devices for Retaining Heat in Steam Boiler and
other Flues.
I, GUILLAUME ARNAUD NUSSBAUM, of 29, Ludgate Hill, in the City of London,
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 has reference to improvements in or applicable to steam boiler
furnaces and the like, and it has for object to provide simple, cheap, and easily
applied means whereby hot gases and air flowing through the flues of furnaces and
the like shall be intimately mixed together so as to produce complete combustion of
such gases and whereby the heat thereof shall be utilized in a more efficient manner
than usual.
For this purpose I provide within the furnace flue, an openwork metallic device
composed of thin metal such as wire in a coiled, twisted, crumpled, matted or netted
017

page_text: condition, which is so disposed in the flue as to fill the whole cross section thereof
and present to hot gases brought in-contact therewith a large conducting surface
that will effectually break up the stream of hot gases and air in the path of which
the said device is placed and intimately mix such gases and air so as to effect prac
tically complete combustion thereof, and bring them into effective contact with the
wall of the flue without offering undue resistance to the flow of the gases, and which
device will itself absorb heat from the said hot gases and act as a heat accumulator
from which heat will be transmitted by radiation and by conduction to the wall of the
flue and thus to the fluid in contact with the opposite side of the wall. Such an open-
work metallic device, which is hereinafter called for distinction a mixing and heating
device, can be made in a variety of forms and be applied to boiler furnaces and the
like in various ways as I shall now describe with reference to the accompanying
illustrative drawings wherein
Fig. 1 shows in central section, an ordinary steam generator of vertical type
provided with a mixing and heating device according to this invention.
Fig. 2 is a similar view to Fig. 1 but showing the said device provided with a core
of refractory non-conducting material.
Fig. 3 shows in longitudinal section, and Fig. 4 in cross section, a steam generator
of the Cornish type provided with my mixing and heating device.
Fig. 5 shows, in central longitudinal section, the application of such a device to a
steam generator of marine type.
Fig. 6 is a longitudinal section of a locomotive type of boiler having my invention
applied thereto.
Fig. 7 shows partly in side elevation and partly in longitudinal section, a piece of
the flue pipe of an oven or a stove provided with a mixing and heating device
according to this invention, and Fig. 8 shows the said pipe and device in cross
'section.
Fig. 9 is a plan and Fig. 10 a cross section, showing one of a number of wire
work sections or parts of which a mixing and heating device according to this
invention may conveniently be built up.
.
Fig. 11 is a similar view to Fig. 10 showing a different form in which the wire
work section can be made.
Figs. 12 and 13 are elevations at right angles to each other, showing another
construction of wirework section.
In the arrangement shown in Fig. 1, the mixing and heating device is built up of
a number of separate wirework sections 1 that are suitably supported in a horizontal
position one above the other within the upper part of the combustion chamber or
Alue 2 of the steam boiler 3 so as to extend across the same in a direction at right
angles to and be in the path of the flame and stream of hot gases passing to the
chimney 4. In this example the sections 1 are of the kind shewn in Figs. 9 and 10
and are each made of wire wound into a coil of rectangular section which is then
bent to circular shape and has its ends connected together so as to form a circular wire-
work device having a number of convolutions extending more or less in a radial
direction from a centre as shown in Figs, 9 and 10. Instead of the wire being wound
into a coil of rectangular section it may be wound into a coil of circular section, as
shown in Fig. 11, but I prefer the cross section shown in Fig. 10 as the straight outer
sides of the convolutions enable a better conducting contact to be made between them
and the wall of the flue in which they are located. The wire of which the sections 1
are made may be of any suitable metal, for example iron, and of any suitable section
and gauge.
In using wire-work sections of the kind shown in Figs. 9, 10 and 11, the adjacent
'sections are so arranged that the wire convolutions of one are opposite the spaces
between the convolutions of the other so as to ensure an effective breaking up and
intermingling of the gases flowing through them without offering an undue resistance
to the flow of such gases. Figs. 12 and 13 show another form in which the wire-work
sections may be made. In this case the section comprises a number of concentric

page_text: rings of spirally wound metal wire separated by rings 1* of thin strip metal, the whole
being connected together by ligatures 1b of metal wire.
In Fig. 1, the several sections 1 of which the heat accumulator is composed are
threaded on a rod 5 which is provided at the bottom with a star shaped support 6
and is connected at the top to a lever 7 by operating which the said sections can
be shaken when it is desired to clear them of any matter that may be adhering
to them.
In Fig. 2 a core 8 of refractory non-conducting material such as fireclay, is
suspended in the centre of the mixing and heating device by the rod 5. The
sections 1 of which the said device is made, are in this case made with a central
opening of a size to fit the core, but in other respects may be of any one of the kinds
herein before described, or of other suitable kind.
In Figs. 3 and 4, wire-work sections of the kind shown in Figs. 9 and 10 and
constituting the mixing and heating device, are shown arranged vertically in the furnace
flue 2 behind the fire-bridge 9. Similar devices may also, if desired, be arranged in
the side portions 2" and bottom portion 2b of the furnace flue external to the steain
generator, the sections composing such devices being suitably shaped to fit such
portions of flue.
Fig. 5 shows a mixing and heating device of the kind described arranged in the
flue 2 and combustion chamber 2° of a marine steam generator.
Fig. 6 shows a locomotive type of boiler having mixing and heating devices
according to this invention removably arranged in the fire tubes 2d and which may
conveniently be composed of wire-work sections of the kind shown in Figs. 9 and 10,
or Fig. 11. In this case the size of the fire tubes may be larger than usual, say about
5 or 6 inches in diameter, and their number be diminished. In a case of this kind
where the flue tube is comparatively small, the sections may be threaded upon a
central rod or bolt provided at the ends with nuts or equivalent so that they can be
inserted in place and removed as one piece.
Figs. 7 and 8 show a piece of the flue pipe of a stove or oven filled with a mixing
and heating device of the kind herein referred to so that the heat of hot gases
passing through the pipe will be transmitted in a more efficient manner than usual
to the pipe and thence to the surrounding air. For this and similar cases, the
mixing and heating device may conveniently be made of sections of the kind shown
in Figs. 9 and 10 or in Fig. 11.
In each case the mixing and heating device is arranged in close contact with the
wall of the flue in which it is placed so that .heat can be readily transferred from it
to the wall or heating surface by conduction as well as by radiation, so that excessive
or undue heating of the device will be prevented. The lateral expansion of the said
device when heated will also aid in ensuring an effective contact between the said
device and flue wall when in use.
As will be seen, the mixing and heating device in each of the examples hereinbefore
described, is so constructed and arranged that it will effect an intimate mixture of the
hot gases and air flowing through the flue in which it is placed so that practically
complete combustion of the hot gases will be produced and a very high temperature
obtained whereby formation of soot and smoke is prevented, or nearly so, and a
greater fuel efficiency than usual obtained. The said device will also serve to deflect
the hot gases against the wall of the flue and whilst it will not offer an undue
resistance to the flow of the hot gases towards the chimney or uptake, it will serve
to lessen or prevent down draught, so that steam boilers, specially those of portable
engines, can be advantageously worked under atmospheric conditions that would
seriously interfere with the working of steam boilers the flues of which were
unprovided with such mixing and heating devices. Furthermore by the use of my
mixing and heating devices, highly efficient express steam boilers can be constructed
in a simpler and cheaper manner than usual. Also by reason of the great amount
of heat stored in such devices, an unfavourable cooling of the heating surface of the
boiler is prevented when the fire door is opened and when cold water is fed into the
boiler.

page_text: I am aware that furnace flues have heretofore been provided with internal ribs or
projections and with wire coils or spirals arranged only in close contact with the
inner surface of the flue so as to retard the passage of hot gases through the flue; also
to provide the fire tubes of steam generators with central screw blades and with cores
provided with screw threads with the object of imparting a spiral motion to the
streains of hot gases flowing through such tubes and so bringing them in contact with
the inner surfaces of the tubes. Such arrangements however have not filled or extended
directly across the flue so as to break up the stream of hot gases at all parts of the
cross section thereof and thus effect an intimate intermingling of all portions thereof
in such a way as to ensure practically complete combustion thereof and also to
abstract heat from the central and intermediate portions of the stream of hot gases
as well as from the outer periphery thereof and at the same time to serve as a
heat accumulator adapted to act both by radiation and conduction, as is the case
with mixing and heating devices constructed and arranged in the manner I have
herein before explained.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
In a steam boiler furnace or the like, the arrangement within the furnace
flue of an openwork metallic mixing and heating device composed of metal such as
wire adapted to fill or extend across the flue without offering undue resistance to
the flow of hot gases and air therethrough and to intimately mix such hot gases
and air so as to effect efficient combustion thereof and to itself become heated and
act as a heat accumulator whereby heat will be transmitted in an efficient manner
from all parts of the stream of hot gases to the wall of the flue, substantially as
hereinbefore described with reference to the several examples illustrated in the
drawings annexed.