A HOT AIR SELF-FEEDING SMOKE CONSUMING FURNACE
Year: 1884

page_text: I, CARL LUDWIG BERGMANN, of 4, Colebrooke Row, Islington, in the County of
Middlesex, Machinist, do hereby declare the nature of said invention for A HOT AIR
SELF-FEEDING SMOKE CONSUMING FURNACE, 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 furnaces for steam boilers and for other industrial
purposes.
The objects of the improvements are: Economy of fuel, and prevention or con-
sumption of smoke.
In the following description reference will be made to the accompanying drawings,
in which Fig. 1 is a side elevation, Fig. 2 a front elevation, Fig. 3 a plan and Fig. 4 a
vertical section of a furnace embodying my invention.
The principal features of novelty are a special kind of movable grate, and a
method or appliance for heating the air before its admission to the fuel.
The grate is formed by two sets of discs A and B arranged in rows on horizontal
shafts. The discs A are placed in alternation with the discs B and mounted loose
on their shafts b, while the discs B are fixed so as to share any rotary motion im-
parted to the shafts b. The discs B are plain, while the discs A are corrugated,
bulged or ribbed, so as to prevent pieces of conl from falling down between the
movable discs. To set in motion the shafts b, which have their bearings in the
sides of the furnace or in brackets secured to the same, I employ worm-wheels C
mounted on the said shafts and gearing into worms D fixed on a horizontal shaft d,
which carries a driving pulley E, or equivalent driving gear.
The coal or other solid fuel is continuously fed to the furnace by allowing it to
fall from a hopper F through an opening f, which may be more or less closed by a
vertically movable slide f
Owing to the continuous slow rotary motion imparted to the discs B, the fuel
which has fallen on the front part of the grate is gradually transported to the back,
and when the more or less consumed fuel has arrived over the last row of discs, the
motion of the discs causes it to fall over the rear side of the grate into an ash pit,
for which purpose a sufficient clearance is left between the rear of the grate and the
rear wall of the furnace (I).
For heating the air intended to entertain the combustion of the fuel, it is first
conducted through a cast iron flue G, H, I K, L which surrounds the grate, and it
is then allowed to pass into the fire place through perforations 1, formed in the wall
of the flue L, as shown in Figs 2 and 4, the choking of the air passage by the coal
at the entrance of the grate being prevented by a flap or inclined plate l.
The different parts of the flue form tubes joined together in such a manner as to
allow the necessary play for expansion and contraction by variations of temperature.

page_text: The air coming down the shaft M provided with a throttle valve m (or equivalent
controlling device) enters the flue or air chamber G which is separated from the
flue L by a vertical partition g; subsequently it passes through the side flue H to
the back flue I, and through the latter to the return side flue K, which leads the air
to the flue L after having been heated by its contact with the hot metallic walls of
the flues.
The furnace may be placed under a steam boiler and connected in suitable
manner with the boiler setting, or it may be used for other industrial purposes
instead of an ordinary furnace grate.
To prevent the influx of cold air to the fuel from the front of the furnace, the
latter is closed by a metal plate extending from the flues G and L down to the
floor, while the influx from the sides is prevented by the brickwork or walls
between which the furnace is placed.
The furnace may either be fixed, or mounted on rollers, as shown by the drawings
to facilitate inspection and repairs.
The discs A, B are preferably made of iron, but refractory earthenware or other
suitable material may be employed.
Instead of composing the air flue of plain rectangular tubes, as shown, they may
have any other suitable cross section and may be provided with internal heating
ribs.
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. A furnace grate, composed of stationary discs plates or blocks, and revolving
discs, the latter being placed between the stationary discs or plates and adapted
to impart to the fuel a slow motion from the front to the back of the grate,
substantially as described.
2. The combination of discs A, with discs B, shafts b, worm wheels C, worms D,
driving shaft d, and pulley F or equivalent driving gear, and shaft bearings,
substantially as and for the purpose described.
3. In furnaces, the combination of a movable grate composed of revolving dises
and intermediate discs or blocks substantially as described, with an air heating
flue composed of metallic tubes forming the walls of the fire place and adapted to
conduct the air around the fire before admitting it to the grate, with means for
controlling the quantity of air passing through the said flue.
4. The combination of a movable furnace grate as described, with an air heating
flue, composed of inlet chamber G having an air inlet, metallic pipes H, I, K, and
outlet chamber L having an air outlet towards the fire place, and means for
controlling the quantity of air admitted to the flue, substantially as described.
5. The combination of a furnace grate composed of revolving discs and inter-
mediate stationary discs or blocks as described, with an air heating flue arranged
as described, means for controlling the admission of air, and means for supplying
the grate with fuel, substantially as described.
6. A furnace composed of movable grate, mechanism for operating the same, air
heating apparatus and an appliance for supplying the grate with fuel, the whole
being mounted on wheels and constructed substantially as described.