Improvements in Steam-boiler and other Furnaces.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in Steam-boiler and other Furnaces.
ESTER
I, EMILIO DE STRENS, of 11, Santa Sabina, Rome, in the Kingdom of Italy.
Chief Engineer of the Central Electric Station, 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 steam-boiler and other furnaces. The furnace constructed
according to the said invention is designed to operate at a high temperature with
the use of solid fuel of any kind and especially fuel having a small heating and
caking power and containing a large portion of slag. In this furnace the action is
not interfered with by the feed and the cleaning and the products of combus-
tion escaping to the chimney are completely burnt. The improved furnace is
characterized by the simultaneous employment of two distinct fires A. A and B B
provided one above the other. Into the upper fire A. A, which is always freely in
communication with the outside through the feed orifice a, the fuel is thrown, whilst
the lower fire B B receives the solid parts of the fuel after they have been well
ignited in the fire A A and nearly all the volatile parts of the same have been
distilled. In the fire B B' the solid residues complete their combustion, and in
proportion as they are consumed they are shifted to the lower part of the fire B B'
and collected in a cavity D from which they are afterwards discharged directly
into the ash pit V.
The draught acts separately upon the two fires through two orifices a and b
which serve respectively for the feed of the fuel and for cleaning the furnace through
the ash pit. V.
For the upper fire A A draught descends through the fuel, that is to say this
fire has a reversed draught, whilst the lower fire has a direct draught. A particular
feature in the arrangement consists in that the products of combustion from either
fire do not traverse the fuel of the other fire, but pass in parallel and concordant
lines at a high temperature into a comparatively large chamber C wherein they
mingle, and it is only on leaving the chamber C that they are conducted to the
apparatus for utilizing the calories produced.
The upper fire is supported by the inclined lateral surfaces of a series of bars m
of refractory material which form a grate and are held by the two transverse
vaults N and M. At its upper part this fire is separated from the rest of the
apparatus by a wall P which may either consist of metal or of refractory bricks as
shown in the drawing. The spaces between the bars m which receive the fuel
constitute downwardly converging openings so that the products of combustion from
the upper fire, which ordinarily require to be at a high temperature for ensuring a
perfect combustion, are raised to the same not only by the radiation of heat from
the lower fire, but also by their being laminated or flattened between the refractory
bars. These products of combustion then pass below the transverse vault M before
entering the mingling chamber C.
Any ordinary grate such as that shown at g may serve to support the lower fire.
The grate does not however extend to the fire-bridge U, but only to a wall in front of
the latter. This wall may be made of refractory bricks and provided with an
opening as shown at G, which is necessary if fuel which is rich in slag employed
and if the slag is to be removed by fusion; otherwise this wall is formed of a
metallic grate suspended from a grate-bearer upon which it may pivot for effecting
the discharge into the ash-pit. This arrangement has for its object to reserve at
the lower part of the fire B B' in front of the fire bridge U a cavity D D of a
certain depth, into which the cinders and the residues from the fire B B are caused
to pass for the purpose of completing the burning of their carbon, whereupon they
fall directly into the ash-pit.

page_text: The air for the lower fire B B enters through the orifice and the ash-pit. By
the arrangement B' D D, I provide at the rear of the furnace for an inlet of air
through D D, which air will become highly heated at the cost of the heat of the
ashes and cinders without a corresponding reduction of its oxygen which owing to
its great oxidizing effect will, when thus heated, act more efficaciously in the
mingling chamber to which all the gaseous products pass.
In this manner the mingling chamber is rapidly raised to and always maintained
at a very high temperature the latter being the initial temperature for utilizing the
calories produced.
I ensure a perfect combustion by the above-described arrangement, so that no
smoke will be produced even with the richest coal.
Besides the openings a and b, a door e is provided for permitting direct access to
the grate g for secondary purposes, such as for lighting the furnace and for pushing
to the rear the materials of the lower fire B B¹. It is optional to arrange this door
either at one or the other side of the furnace.
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 :-
A furnace, substantially as hereinbefore described in which two fires are arranged
one above the other, the upper fire having a reverse draught and being supported by
a series of bars of refractory material leaving openings between them through which
the products of combustion from this upper fire pass, whilst the lower fire which is
supplied with fuel falling in an incandescent state, from the upper fire, has at its
rear a cavity communicating directly with the ash-pit, and in which the fuel
completes its combustion all the products of combustion being conducted to a
mingling chamber subjected to the oxidizing action of the air passing through the
said cavity before they are utilized.
Dated this 15th day of January 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.