Improvements in Furnaces.
Year: 1896

page_text: Date of Application, 9th Oct., 1896-Accepted, 28th Nov., 1898
Improvements in Furnaces.
A communication, by MORITZ HERWIG, of Dillenburg, of Hesse-Nassau, in, the
Empire of Germany, Manufacturing 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, 118 New. Street, Birmingham, in
the County, of Warwick and 322 High, Holborn.in the County of Middlesex, Civil
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:-
In the generator furnaces hitherto employed the preliminary heating of the. air
which is supplied. to the gases produced in the furnace for the purposes.of.com-
bustion, ordinarily takes place in regenerators, which are heated by the. waste heat
from the heating. chamber so that such waste heat is lost for other purposes, such
for instance as for heating a steam boiler. In other, cases the waste heat is
employed for steam producing, but only passages which are arranged in the walls
of the generator furnace itself and in which merely the warmth of the walls of the
furnace acts, are then employed for preliminarily heating the air, which of course
has for its consequence only a comparatively moderate warming of the air. and a
correspondingly diminished heating effect..
By this invention a generator furnace is created which renders it possible to
fully and entirely utilise the waste heat from the heating chamber for..the
production. of steam and, yet simultaneously, without any special fire, to still obtain
an extremely intense superheating of the air supply to the generator gases.. This
extremely practical action. is attained by an air superheater being. constructed in
the generator furnace, and this being operated by one or more divided.flames taken
from the hottest part of the generator furnace.
Three forms of construction are shown in the accompanying drawing.of.the
generator furnace arranged in the manner.named.
Figure 1 is a vertical longitudinal section of a simple form of construction.of
the furnace;
Figure 2 is a vertical cross-section carried through the air superheater. on. the
line za Fig. 1;
Figures 3 and 4 show a form of construction of a semicircular generator furnace
Fig. 3 being a vertical section, and Fig. 4 a section on the line y y Fig. 3, whilst
Figures 5 and 6 show one of circular section, Fig. 5. being a vertical-section, and
Fig. 6 a section on the line-z z Fig. 5.
A partition or wall b formed of firebrick is constructed behind the front wall.a
of the furnace, which partition b. ends at the top a little below. the roof. c of the
furnace. The partition 6 is connected with the furnace wall at by means of bricks d
which extend across. and are arranged zigzag in rows... Below the wall or partition b
is a grate e which is accessible by means of an opening f which may be airtightly
closed together with the ashpan situated beneath the grate by means of a door. g.
The nozzle h of a blast arrangement opens into this chamber beneath the grate.
Openings are formed in the lower part of the-partition, band-are in communi-
cation with the outer air and also with the intermediate space between the walls a
and b. The front wall of the furnace is open to the height of these..opnings.i.
D

page_text: The chamber lying in front of these openings is closed in front by means of a flap
or valve k arranged on the front wall of the furnace, which flap admits free access
of the air at its lower end.
The fire chamber is covered with an arch or dome n provided with a suitable
opening m for the escape of the gases produced. Above this arch n another arch
or cover o is provided attached to the upper edge of the partition 6 so that there
is formed beneath the furnace roof two draughts p and q one above the other which
afterwards unite to form a single draught.
The mode of action of this generator furnace is as follows:-
After the furnace has been fed through one or more of the filling apertures
formed in the side walls and set alight, air is blown in through the nozzle or pipe h.
This air conveyed in under pressure and passing through the grate into the furnace
chamber produces exactly on the grate a very vigorous combustion.
As air is constantly forced in, the gases of combustion developed are exposed to
a corresponding pressure in consequence of which a portion of the combustion
gases escape at once through the openings i. These very gases escaping through
the openings i develop a very intense heat as in consequence of the existing excess
of air on the grate they form the product of a complete combustion, in fact these
flames have entirely the appearance of fine jets.
The pull of the chimney of course acts in the chamber between the walls a and b
and this draught draws the flames into the space between the walls a and b so that
they cause the bricks d connecting the two walls to be heated, so that the air
passing in at the under edge of the valve k in large quantities undergoes an
extremely strong heating, both through the flames themselves and also through
passing over the beated bricks. The heating of the bricks d is also considerably
assisted by the air superheater being constructed inside the generator furnace.
The gases developed in the fire chamber pass through the opening m into the
passage p, the slightly heated air encounters the gases in the passage r, and there
is there developed only an extremely hot smokeless flame which may be utilised
for various technical purposes, such, for instance, as the heating of a puddling
furnace or a welding or reheating furnace or the like. After thus utilising the
high heat of the flame the whole waste heat may be employed for the production
of steam.
I
In the semicircular form of furnace shown in Figures 3 and 4 and the circular
one shown in Figures 5 and 6, the chamber for heating the air extends round the
entire walls of the generator furnace.
In addition to the flat grate e, Figures 3 and 4, which closes the furnace chamber
below, a step-shaped grate e is arranged over which the divided flames pass
through the openings into the superheater. On the opposite straight side the
flames pass through the openings into the superheater limited by the wall or
partition b. The valves or dampers k are adjustable in order to allow of the
supply of air to the superheating chambers being regulated. The air superheater
connected with the round part of the wall of the furnace is shut off by the cover o
from the interior of the chamber so that the air heated therein passes between this
cover o and the roof c of the furnace and thus encounters generator gases entering
the passage from above the upper edge of the wall 6. The superheated air
flowing behind the wall 6' on the other hand passes from below against the layer
fed from
of generator gases flowing away over the wall b¹ so that the latter
above and below with superheated air.
In the form of construction shown in Figures 5 and 6, the bottom of the
chamber may be constituted of a basket grate on the upper edge of which there
are openings i all round for the passage of the flame to the air superheaters lying
all round and extending over the whole wall of the generator furnace. This air
superheater extends up to the tubular top or discharge pipe of the furnace so
that the rising generator gases at the upper edge of the wall which internally
limits the superheater are enclosed on all sides by the superheated air, whereby as
thorough and even a mixture of gas and air as possible is produced.

page_text: The grates beneath which air is blown in through the nozzle or pipe h, are of
course completely closed to the outside by means of doors.
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, 1 declare that what I claim is :-
1. A generator furnace having an air superheater (b d) operated by one or more
branch flames derived from the generator furnace substantially as herein before set-
forth.
2. A form of construction of the herein-described generator furnace consisting
in the air superheater being so constructed in the furnace that the outer wall (a).
of the furnace forms simultaneously one outside wall of the air superheater, and
the opposite wall (6) of the latter encloses or limits the fire chamber and is.
provided with discharge openings (i) for branch flames substantially as described.
3. A form of construction of the herein-described generator furnace consisting
in several air superheaters being constructed opposite one another in the furnace,
and the mouths of said air superheaters being so arranged that to the layer of gas.
quitting the generator there is conveyed from above and also from below a super-
heated layer of air substantially as hereinbefore described with reference to.
Figures 3 and 4 of the accompanying drawings.
4. A form of construction of the herein-described generator furnace consisting
in the air superheater being extended all round the entire wall of the furnace and
having with the latter its mouth at the top in the form of a tube shaped extension,.
whereby a most thorough utilisation of the radiating heat of the furnace is
attained, and the generator gases given off are mixed or surrounded on all sides
with superheated air substantially as herein before described with reference to.
Figures 5 and 6 of the accompanying drawings.
Dated this 8th day of October 1896.
WM. P. THOMPSON & Co.,
Agents.