Year: 1888

page_text: Date of Application, 14th Jan., 1888
Complete Specification Left, 15th Oct., 1888
Complete Specification Accepted, 16th Nov., 1888
I, KARL ARNOLD BRUNNSCHWEILER of 8 Charlotte Street, Manchester in the
County of Lancaster, Manufacturer do hereby declare the nature of this invention to
be as follows:-
My invention relates to domestic fire grates and has for its object a better utilisation
of the heat produced in such grates than is obtained by their ordinary arrangement.
As generally arranged, the flue from such grates ascends straight up the chimney and
the heat passing up the flue is wasted, so that only a small percentage of the heat
I utilise the heat ascending
developed by combustion is utilised in warming the room.
the flue by my improved arrangements in the following manner:
A short distance above the grate I place into the flue which ascends to the chimney
an adjustable damper, and below the damper I make lateral openings in the flue also
provided with adjustable dampers. The openings in the flue lead into flue chambers
built up on each side of the central flue leading to the chimney. These flue chambers
may extend over the whole width of the chimney breast and occupy part of its depth,
leaving space behind them for the chimney flues from grates in rooms below to pass
behind the flue chambers, or the latter may occupy only the middle part of the
chimney breast and the flues from grates in lower rooms may pass up at their sides
as ordinarily is the case with open fire grates. The front of the flue chambers I
build up by preference of tiles, but they may formed of slabs of terra cotta, cast
Into the flue chambers I
iron, bronze or other materials ordinarily used for stoves.
place division plates or shelves extending from each side alternately to within a
short distance of the other side, so that the hot gases from the fire when directed
into the flue chambers have to ascend through them in a zig zag path. In some
cases the division plates may be placed vertically and the hot gases caused to travel
up and down, but by preference I place the division plates horizontally. I usually
form them of thin slabs or plates, making the flues of square section, but the division
plates may also be made of triangular section or thicker at the back, so as to form
triangular or trapeze shaped flues wider at the front for the purpose of throwing the
hot gases more to the front. The flue chambers extend up to a shorter or greater

page_text: distance from the ceiling and have openings at their sides at the top through which
they communicate with the central chimney flue. The dampers herein before referred
to are by preference arranged to swivel, and the flue chambers are provided with
air tight doors arranged in suitable places for cleaning the zig zag flues in the
chambers.
When first lighting the fire the damper in the central flue is opened and the dampers
in the lateral openings leading to the flue chambers are closed, when the smoke will
ascend the central flue to the chimney. When the fire burns clear, the central damper
is closed and the lateral dampers are opened, and the heat then passes in a zig zag
path through the flue chambers and enters the central flue at their top. The fronts
of the chambers becoming heated heat the air in the room and a large part of the
heat ordinarily wasted is utilised for heating purposes, the flue chambers forming
with the open fire grate an equivalent for a stove with an open grate.
Dated this 13th day of January 1888.

page_text: COMPLETE SPECIFICATION.
Improvements Connected with Domestic Firegrates.
1, KARL ARNOLD BRUNNSCHWEILER of 8 Charlotte Street, Manchester in the
County of Lancaster, Manufacturer, 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 domestic firegrates and has for its object a better utilisation
of the heat produced in such grates than is obtained by their ordinary arrangements.
As generally arranged the flue from such grates ascends straight up the chimney
and the heat passing up the flue is wasted, so that only a small percentage of the
heat developed by combustion is utilised in warming the room. I utilise the heat
ascending the flue by my improved arrangement in the following manner.
A short distance above the grate I place into the flue which ascends to the chimney
an adjustable damper and below the damper I make one or more openings in the flue
also provided with dampers. The openings in the flue lead into one or more flue
chambers. These may be built on one or on both sides of the flue leading to the
chimney, or they may extend over the whole width of the chimney breast and occupy
part of its depth, leaving space behind them for said chimney flue and other flues
from grates in rooms below to pass them at their back, or they may occupy only
the middle part of the chimney breast and the flues from grates in lower rooms may
pass up at their sides as usual. The front of the flue chambers I build up by
preference of tiles, but they may be formed of slabs of terra cotta, cast iron, bronze
or other materials ordinarily used for stoves. Into the flue chambers I place division
plates or shelves extending from each side alternately to within a short distance
of the other side, so that the hot gases from the fire when directed into the flue
chambers have to ascend through them in a zig-zag path. In some cases the
division plates may be placed vertically and the hot gases caused to travel up and
down, but by preference I place the division plates horizontally. 1 usually form them
of thin slabs or plates, making the flues of square section, but the division plates may
also be made of triangular section or thicker at the back so as to form triangular
or trapeze shaped flues wider at the front for the purpose of throwing the hot gases
more to the front. The flue chambers extend up to a shorter or greater distance
from the ceiling and have openings at the top through which they communicate
with the chimney flue. The flue chambers are provided with air tight doors arranged
in suitable places for cleaning the zig-zag flues in the chambers.
On the drawing appended hereunto fig. 1 shows a front view partly in section
along line A B in fig. 2 of a firegrate with flue chamber extending above the mantel
over the entire width of the chimney breast, fig. 2 a cross section and fig. 3 a front
view similar to that shewn by fig. 1 but with the damper in the position closing the
chimney flue. a is the grate from which the chimney flue b ascends, being carried
behind the flue chamber c c, which communicates with the flue C through the flue d
at the bottom and the opening e at the top. The damper is shewn sliding in a

page_text: frame and provided with a handle for moving it, but any other suitable kind of
damper may be used. When the damper is in the position shewn by fig. 1, the
chimney flue is in direct communication with the grate while the communication
between the grate and the flue chamber c is closed. The fire is lit with the damper
in this position, when the smoke will ascend the central flue. When the fire burns
clear the damper is shifted into the position shown by fig. 3 and the hot gases will
then pass through the flue d into the chamber c c and ascend through it in the
direction indicated by the arrows till they enter the chimney flue C again at the top
through the opening ĭ.
Fig. 4 shows a modification of the arrangement, the flue h being arranged to ascend
straight from the grate at the front of the chimney breast, with two flue chambers i i¹,
one on each side of flue and communicating with it at the bottom through
flues and at the top through openings n n¹. Two dampers m m¹ are used in this
case. In the position of the dampers shewn, the hot gases from the fire pass
through the flue chambers as indicated by the arrows. By shifting both dampers to
the right, the flues kk' are closed and direct communication from the grate to the
chimney flue is established.
Fig. 5 shows an arrangement with the chimney flue o at one side of the chimney
breast and the chimney p occupying the remainder, and communicating with the
grate through the opening 9 and with the flue o at the top through the opening r.
By shifting the damper s to the right direct communication between the grate and the
flue o is established and the chamber p shut off.
I do not confine myself to the arrangements shewn on the drawings, but these
can obviously be varied according to the existing arrangements of chimney flues.
The flue chambers can be used with any kind of open firegrate and fuel burnt in the
same and are applicable to grates burning coal, coke, gas, or oils.
The fronts of the chambers become heated by the hot gases passed through them,
and partly also by the heat passing up the chimney flue, and heat the air of the
room, and a large part of the heat ordinarily wasted is utilised for heating purposes,
the flue chambers forming with the open firegrate an equivalent for a stove with an
open grate.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
In combination with open firegrates the arrangement of a flue chamber or
of flue chambers in the front part of the chimney breast through which the hot
gases from said grates can be made to pass substantially as hereinbefore described
and illustrated and for the purpose set forth.
Dated this 12th day of October 1888.