Improvements in Fire Bridges for Furnaces.
Year: 1892

page_text: Date of Application, 1st July, 1892-Accepted, 6th Aug., 1892
COMPLETE SPECIFICATION.
Improvements in Fire Bridges for Furnaces.
HERMANN KOWITZKE of Hasenhaide No. 21, Berlin in the Empire of
Germany 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 :-
My present invention consists in a firebridge for all kinds of furnaces, and its
object is to provide a device whereby the many disadvantages accruing from the
use of firebrick bridges shall be obviated by substituting therefor a bridge of cast
or wrought metal.
According to my invention the bridge consists of a hollow structure of cast or
wrought metal tapering towards the top and open at top and bottom said bridge
being further provided with transverse ribs or partitions as may be found
necessary.
I have found that bridges constructed on this system are more durable than those
of firebrick and can be more easily taken out and replaced when required as they
are mounted-on a suitable seating or support which is not exposed to the action of
the flames.
In order to make my invention more easily intelligible, I refer to the accom-
panying drawings forming part of this Specification, in which similar letters denote
similar parts throughout the several views.
Fig. 1 is a sectional elevation of my improved device arranged in a boiler
furnace.
Fig. 2 is a plan of Fig. 1.
Figs. 3 and 4 show modified forms of the bridge.
Figs. 5 and 6 show in section and front elevation another modification.
a is the fire bridge consisting of the hollow structure, open at the top and bottom
and tapering towards the top; it is advantageously provided with transverse ribs
or partitions which may extend the full height of the wedge shaped bridge or
only partially up the same as may be advisable for the purpose in question. These
ribs or partitions may however be entirely omitted.
The bridge is provided at its lower end with a damper device d which may be
regulated by the rod e to increase or diminish the draught. is the grate.
Figs. 3 and 4 simply show in back elevation modified forms of the bridge, the
one having its upper edge curved, the other having a straight upper edge.
In Figs. 5 and 6 the fire bridge is constructed with the lower opening arranged
sidewards instead of or as well as at the bottom, so that air can enter at the lower
front of the bridge.
The fire bridge hereinbefore described has the advantage that it can be more
easily and conveniently fitted into new boiler furnaces whilst it can be removed
and replaced in old furnaces with greater facility than fire brick bridges can be
taken out or built in. The hollow metal bridge can be made in exactly the
required size and form, and need simply be secured to the support or seating
arranged therefor at the further end of the grate. I have also found that such
metallic bridges last considerably longer than fire brick bridges and that they do
not lose their shape by crumbling as in the case of the latter, which is of great
importance for the advantageous burning of the boiler furnace. The continual
draught passing through the bridge, and the fact of said draught increasing towards
the top, owing to the conical shape of the bridge, not only prevents the walls from
burning but also prevents the deposit of soot and other products of combustion in
the flues. This is due to the fact that the fresh heated air entering the flue by way
of the bridge causes energetic and complete combustion.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is.
In furnaces of all kinds.
1. A metallic fire bridge tapering towards the top and open at the top and
bottom substantially as described.
2. A hollow metallic fire bridge tapering towards the top and open at top and
bottom, and having one or more transverse ribs or partitions substantially as
described.
3. The combination with a hollow metallic bridge tapering towards the top and
open at the top and bottom, of a damper device d arranged in the lower end, and an
operating rod e therefor substantially as described.
4. The combination of the hollow bridge a tapering at the top and open at top
and bottom, and having the transverse ribs with the damper device d and rod &
substantially as described and illustrated.
Dated this 1st dow of July 1802
HERBERT & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.