Improvements in and relating to Furnaces.
Year: 1895

page_text: Date of Application, 15th May, 1895-Accepted, 6th July, 1895
Improvements in and relating to Furnaces.
I, THEODOR BURMEISTER of Kengeragge near Riga, in the Empire of Russia,
Engineer, do hereby declare the nature of my said 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 relates to a furnace, in which a tripartite grate consisting of a
horizontal front-grate, an inclined middle-grate and a horizontal rear-grate is
combined with a vault covering the front grate and terminating in a frontal arch
above the middle portion of the inclined grate; the latter is of a special
construction, and the purpose of the whole is to obtain a perfect combustion
with but a slight chimney-draught, as will all be more fully described hereinafter.
In order to make my invention more clear, I refer to the accompanying
drawing, in which similar letters denote similar parts throughout the different
figures.
Figure 1 is a vertical longitudinal section through my improved furnace, showing
the same combined with a tubulous boiler;
Figure 2 is a vertical longitudinal section through the inclined middle grate,
drawn on a larger scale than that of Figure 1; and
Figure 3 is a vertical cross section through two bars of the middle grate, drawn
on a larger scale than that of Figure 2.
The inclined grate b, Figure 1, which is arranged between the front-grate a and
the rear-grate c is composed of bars of special construction, as represented
in Figures 2 & 3. Each of these grate-bars consists of a thick-walled pipe f and
a bar proper g, the lower portion of which latter is grooved so as to correspond
to the shape of the pipe. Both parts are connected with each other by hoops
or bows n.
All the said pipes f terminate at their lower ends into a hollow bearing-bar e,
the channel of which is connected with a water-conduit, a reservoir or the like, so
that the pipes are filled with water up to their tops. The pipes f are provided at
their tops with small holes (indicated in Figs. 2 & 3) letting the water escape out
of the pipes into the numerous small spaces and grooves existing between the
neighbouring surfaces of the pipes fand the bars g. That water, on flowing down-
wards, (partly on account of adhesion, partly on account of gravity) between the
said surfaces, is heated, and turned into steam; the latter escaping at the two sides
of each bar enters the glowing coke laying on grate b, and is decomposed thereby ;
the products of the decomposition mix with the gases coming from the front-grate,
and the combustion of those gases is greatly promoted thereby.
The vault d, which covers the front-grate wholly and the middle grate but half,
is somewhat inclined towards the latter and terminates in a frontal arch d¹.
Therefore, the gases that are evolved by the fuel of the front-grate, and are mixed
there with air, are caused to approach the glowing fuel of the middle-grate; and the
air, whilst cooling the vault, is heated to a high degree; the combustible gases,
therefore, are nearly perfectly burnt, and the remainder of them is burnt together
with the product of decomposition of the steam, as above explained. The access
of air is regulated by the front-slide h.
In feeding the furnace, the glowing coal of the front-grate is shoved from the
latter down upon the top-portion of the middle-grate, from where a part of the coal
glides downwards according to the progressing combustion. The slag and other

page_text: incombustible components arrive finally on the slag-grate c, and are removed from
the latter through a door c¹.
After the front-grate has been fed with fresh coal, part of the glowing coal that
has been shoved forward upon the top-edge of the inclined grate is drawn backwards,
and distributed over the layer of the fresh coal, so that the gases evolved by the
latter are compelled to flow through the said glowing coal.
The improved furnace offers the advantage, that with but a slight excess of air a
perfect combustion of the fuel may be attained, without requiring for such a result
a particularly clever stoker. The maintenance of the necessary high temperature
is done by the second grate (the inclined middle grate) and the frontal arch of the
vault, the latter at the same time preventing the boiler from being cooled by the fresh
air. The stoker is less exposed to the heat, than is the case with a plane-grate and
step-grate and the slacking off need be made more seldom and requires less time
than with any other grate.
The draught of the chimney need be but slight, which is of importance for the
use of my improved furnace for tubulous boilers, in that the useful effect of the
latter is greatly impaired, if much air is sucked behind the fire-bridge into the flue.
The construction of my improved furnace is such that the latter may easily be
substituted for an existing plant.
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 :-
1. In a furnace, the combination with a front-grate, and a lower rear-grate, of
an inclined middle-grate, the bars of which are provided with water-channels having
apertures adapted to let the water escape, for the purpose as described.
2. In a furnace, the combination with a front-grate, and a lower rear-grate,
of an inclined middle-grate the bars of which are provided with channels adapted
to lead water from the lower end to the top-end of said bars, said channels having
apertures adaped to let the water escape at the top of said inclined grate, for the
purpose as described.
3. In a furnace, the combination with a front-grate, and with a lower rear-grate,
of an inclined middle-grate, the bars of which are composed of pipes, and of
bars proper connected with said pipes, the latter having apertures adapted to
let the water escape; a vault covering the said front-grate as well as part of
the said inclined grate, said vault terminating in a frontal arch, for the purpose as
described.
THEODOR BURMEISTER,
By Geo. H. Rayner,
37 Chancery Lane, London, W.C., Agent for the Applicant.