Year: 1889

page_text: A communication from abroad by GEORG WILHELM LÖNHOLDT, of No. 1, Schelling-
strasse, Berlin, W., in the Empire of Germany, Architect and Engineer.
I, WILLIAM PHILLIPS THOMPSON F.C.S. M.I.M.E. of the Agency for Foreign
Patent Solicitors 6, Lord Street, Liverpool and 6, Bank Street, Manchester, both in
the County of Lancaster & 323 High Holborn in the County of Middlesex, Civil
Engineer do hereby declare the nature of this invention and in what manner tho
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
In grates as at present usually constructed, two great evils are found. Namely,
that the fuel is incompletely burnt, and certain parts of the grate itself, which come
in direct contact with the flame, are quickly worn out. The incomplete combustion
has the disadvantage that the fuel is partly wasted, and dangerous gases, such as
carbonic acid gas, are produced which in stoves and similar grates offer considerable
danger to life and health.
In consequence of the heavy wear on certain parts of the grate these parts have
to be made especially strong, and thereby the heat given off at these parts is
considerably limited.
Those evils are avoided by the improvements which form the object of this inven-
tion, in which the flame is drawn down through a fire proof body, and is so
concentrated that the separate tongues of flame are forced through, and, if a sufficient
supply of warm fresh air be supplied, a complete combustion is effected.
By causing the flames to pass downwards and concentrating them in a com-
paratively narrow combustion chamber, the radiating surfaces that are brought in
immediate contact with the flames are protected from burning; and this construction
not only prevents the stove from falling to pieces or warping, but, in case of faulty
joining of the parts, prevents danger from the joints in consequence of swelling, such
as is common, for instance, in Dutch tile ovens. The reason of this is, that the
destructive oxygen compounds which are converted by the increased draught into
carbonic acid, cannot escape on account of this increased draught.

page_text: In the accompanying drawings the grate is shown in Figures 1 and 2 ás applicable
for warming a room, as an example.
In the middle of the grate bars h is the combustion chamber a of a saddle or conical
shape of fire-proof material, the bars h being divided into two groups so that a double
grate is formed. The combustion chamber a has, at its apex, a long narrow slit b,
called the "furnace slit." This slit & may, with advantage, be made conical, that is
to say, narrowing towards the exit. This chamber a ends at the base beneath the
grate bars in a tubo shaped portion, the back pipe of which s Figure 2, opens out into
the chimney, and which can be closed by a damper, while the front portion c of the
pipe projects through the front wall of the stove, and is closed by a window, or it may
serve as an inlet for superheated air or steam into the combustion chamber, and in the
latter case it is suitably finished off or ornamented.
Besides this a vortical passage e with an opening r for cleaning purposes, leads
down through the ash box, and to this passage è are attached circulating pipes g for
drawing off the combustion gases if desired. Over the grate bars the casing i,
made of waving or corrugated tin, hung adjustably, by means of which, when there is
a difference of temperature between the casing and its shell, the latter is preserved
from any destructive distortion. This casing i is divided by a channel m which
widens out towards the bottom, and the burning material is kept from falling
thereon by a saddle or cowl o, for which also a tube may be substituted. The side
of the widened part at the ends of the channel m prevent the burning material from
falling into the slit b.
The stove may be heated at will, and the pipe s may be used to conduct the furnace
gases direct to the flue. The flame produced at once heats the walls of the com-
bustion chamber a, and since the slit is only of slight width, tho flames which rush
from opposite directions with a powerful draught towards the flue will be forced
through the said slit, so that a complete combustion is effected. This draught is
further increased by leading the air from above into the furnace through regulating
screws in the furnace doors, which will be the most natural, because the most direct
course is provided through which the furnace gases are conducted to the flue.
The result of this is that the oxygen compounds produced by the decomposition of
the fuel cannot accumulate in the casing firebox. Further, the downward draught,
through the casing or firebox, carrying with it the gases developed in the latter,
effects a constant cooling of the walls, and especially of the ends of the casing, which
are thus kept from burning, this being one of the greatest evils in the stoves as
hitherto constructed.
When the stove is thoroughly alight the damper may be closed in the flues so that
the furnace gases produced in the combustion chamber a will pass through the
circulating pipes 7 before reaching the chimney.
Since in this arrangement of the firegrate the flames do not have any baneful
influence either on the stove plates k or on the sides of the casing, those parts may
be made very thin, so that they can be used to a very considerable advantage, which
is a valuable consideration in the construction of stoves, as it allows a very advan-
tageous method of heating. The thin hot walls of the casing i hasten the decoin-
position and conversion of the fuel into gas, while, as above, shown the complete
combustion of the guses takes place in the slit b, or the combustion chamber a.
The combustion chamber a may be single or double walled, and in the latter caso the
space between the walls may be filled with air or liquid; there may be one or more
combustion chambers in the furnace, in short it may be varied at will in its mode of
application, material and position, so long as it answers the above object. It should
be kept in mind that the flames are forced downwards by the construction of the
combustion chamber, and are compressed on passing through the latter.
It is plain that with this arrangement of the grate it can be separated some distance
from the fuel.
The grate bars are not necessary for carrying out the invention for it can be applied
to heating apparatuses without bars, since it is mainly by the combustion chamber
that the main object is attained.

page_text: Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :-
1. A heating apparatus, distinguished by the application of one or more com-
bustion chambers a, each being provided at the top with a comparatively narrow slit b,
and placed inside the fire box in such manner that the flames will flow downwards on
entering the said combustion chamber or chambers where they will be condensed and
pressed together, with the object of producing a complete combustion within the
combustion chamber and saving the wear on the surrounding walls, substantially as
described.
2. In a heating apparatus such as described, the application of an adjustable casing i
in such manner that both the walls of the casing and the dividing walls are provided
with grooves or channels running in the direction of the draught, with the object of
producing a thorough decomposition of the fuel and of preventing the accumulation
of oxygen in the fire box by the application of a powerful draught in the combustion
chamber, substantially as described.
0011
1 1000
WM. P. THOMPSON & Co.,
Agents for the Applicant.