Improvements in Means for Consuming Smoke in Furnaces.
Year: 1895

page_text: Date of Application, Sth Oct., 1895
Complete Specification Left, 9th July, 1896-Accepted, 3rd Oct., 1896
PROVISIONAL SPECIFICATION.
Improvements in Means for Consuming Smoke in Furnaces.
MATTHEW DAVISON 13 Lawson Street North Shields Iron Founder &c. do
hereby declare the nature of this invention to be as follows:―
The combustion tube or belt smoke consumer consists of asbestos, cast or
wrought iron (or other material) and perforated with air holes on the under side.
It is fixed onto the backbridge with an air passage to it, placed either immediately
above or behind same, or in the combustion chamber at the end of fire tube. The
backbridge is double with a perforated plate on top and the air is conveyed to it
either by bars in one or more lengths, or by tube or tubes direct to the backbridge
(or otherwise). If by tubes the air is regulated by small valves at the front end
of the tube, if through the bars it is regulated by the space in the bar, or without
the tubes by a trellis hole on the backbridge. The tube or belt to work separately
or in conjunction with the backbridge, or the whole combined.
Dated this Seventh day of October 1895
I, MATTHEW DAVISON of No. 13 Lawson Street North Shields in the County
of Northumberland Iron Founder 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 :-
My invention relates to an apparatus consisting of a combustion tube or hollow
belt, in the form of an arch, for effecting the better consumption of smoke, and
further, in return tube boilers, acting to protect the lower rows of tubes from the
direct impingement of the flame and gases upon their ends and prevent them being
choked by soot. The apparatus is placed at the back end of the furnace pro-
jecting into the combustion chamber and forms an open arch, internally of the
curve of the furnace, and having around it an annular hollow belt for the reception
of atmospheric air which enters from the back plate of the bridge, which will
preferably be double, forming a hollow box into which the air is conveyed from
the stoke hole, by hollow bars, by a tube (or tubes) or through the ashpit by
trellis openings in the front of the bridge, in each case regulated as to quantity by
valves, gratings or other means. The air thus entering the hollow bridge passes
into the arched belt at both sides and is distributed downward among the flame,
gases and other products of combustion through air holes provided in the under-
side of the belt. Air to further assist combustion and smoke consumptiou may
also be introduced into the furnace through perforations in the crown of the
bridge in combination with the apparatus. The apparatus practically lengthens
the furnace to the extent of its projection into the combustion chamber beyond the
tube plate and so the flame, gases and other products of combustion do not impinge
upon the ends of the lower rows of tubes to which the apparatus forms a shield.

page_text: The apparatus may be made of cast metal, iron plates silicate or fire clay,
asbestos or any other suitable material moulded or otherwise formed to the
required shape and may conveniently be bolted upon the back plate of the bridge
and to the tube plate.
The forms and modes of construction will be varied to suit the application to
various types of furnaces but as specially adapted to internally fired boilers with
return tubes I have so illustrated my invention on the accompanying drawings
which I will now describe.
Fig. 1 is a section through the back end of a furnace with a portion of the
combustion chamber and the two lower rows of tubes;
Fig. 2 is a back view of the apparatus, one half in section; Fig. 3 is a plan of
same and
Fig. 4 is a front view of the hollow bridge.
A is the furnace, B the combustion chamber; C the lower rows of tubes; D is
the hollow bridge, shewn as made, for convenience of application to existing
boilers, of a front plate D¹ carrying the rear ends of the fire bars and fire brick
bridge, and a back plate D2 bolted together with an aperture D³ between them for
the passage of air to the crown of the bridge through a perforated strip D* by
which air enters into the furnace. The apparatus E is shewn bolted to the back
plate of the bridge and to the tube plate by the brackets E¹ and projecting into the
combustion chamber the arched hollow belt E2 following the curve of the upper
half of the furnace and fitting close against the tube plate below the lower row of
tubes. E are the openings for air, at each side, from the hollow bridge into the
arched hollow belt E2 and E* are holes in the underside of the belt through which
the air passes to effect the consumption of smoke.
In this instance air passes from the stoke hole into the bridge through tubes F
and thence passes into the apparatus and also, if required, through the air holes in
the crown of the bridge into the furnace. The air may be supplied either under
natural or forced draft and cold or heated. The arrows in dotted lines shew the
direction of the flame gases and other products of combustion from the furnace
into the combustion chamber and thence into the tubes and the arrows in full lines
shew the direction of the air currents to mix with them and consume the smoke.
It will be seen that the flame gases and other products, in passing round the belt
of the apparatus on their way to the tubes, do not impinge upon the tube ends to
burn them and cause leaks and such smoke as remains does not deposit soot
by entering the tubes direct but rather deposits such soot in the combustion
chamber.
My invention may be adapted, in various modified forms, of construction and
application, to other types of boilers, the smoke consuming apparatus being in
cach case fitted so as to distribute air amongst the flame, gases and other products
of combustion, either behind the bridge in horizontal furnaces such as the Cornish,
Lancashire or Galloway types with flues or tubes, in locomotive or vertical furnace
boilers at a point, either vertically or horizontally, between the fuel on the grate
and the flues or tubes and it may be of various forms best adapted to each case,
such as a complete or partial hollow ring into which air is received from the
atmosphere and this hollow ring may be made of fire clay or other siliceous
refractory material or of cast iron or iron plates protected if necessary by a
refractory shield or casing.
Having now particularly described and ascertained the nature of said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
First. The improvements in consuming smoke in furnaces consisting in the
application of an apparatus situated behind the bridge, in furnaces so fitted,
forming a tubular chamber into the interior of which atmospheric air is received
to be distributed in jets amongst the flame, gases and other products of combustion
as they pass from the furnace on their way to the tubes or flues, the air thus

page_text: introduced effecting the prevention of smoke and economy of fuel by the more
efficient combustion of the carbonaceous gases substantially as described.
Second. The smoke consuming apparatus adapted to an internally fired return
tube boiler, comprising the arched hollow belt E perforated on inner side with
openings E communicating with the hollow bridge D to which it is bolted, said
bridge receiving the atmospheric air and delivering it to the apparatus E and having
provision for supplying air also to the furnace through a passage D³ to the perforated
strip D the apparatus effecting the consumption of smoke and also protecting the
ends of the lower rows of tubes; the whole combined, constructed and operating
substantially as described and illustrated on the drawing.
T 1
1000
T. J. DANSON,
Patent Agent,
Newcastle-upon-Tyne, Agent for Applicant.
Lurera Con nio sura na