Improvements in Steam-boilers with Divided Furnace Flue Tubes.
Year: 1888

page_text: Improvements in Steam-boilers with Divided Furnace Flue Tubes.
I, GEORG EGGERS of Sudenburg near Magdeburg 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 hy the
following statement :-
My former Patent (No. 15,251) in 1886 relates to the construction of steam
boilers, with internal flues of which the fire tubes are divided by two partition walls.
The present invention relates to forming these partitions of peculiarly shaped curved
or undulated metal plates or of smooth plates, with one or two undulated tie-plates
placed between, which serve to create a greater stiffness of the boiler plate used in the
partitions, so that the said partitions cannot be forced out of shape, and the necessity
for strengthening them with iron stays is avoided.
These improvements are clearly shown in the accompanying drawings.
Fig. 1. is a longitudinal section of the boiler with two fire tubes, as shown
crossways in Fig. 2 taken at the line x y.
Fig. 2. is a cross section of the same boiler.
Fig. 3 is a horizontal section of the same boiler at the line ¹ y¹.
Fig. 4 is a horizontal section of a boiler with one fire-tube, with the fire grating
inserted.
"
Fig. 5 is a cross section of two fire-tubes on an enlarged scale.
Fig. 6 is a horizontal section of the partition walls, showing the curved tie-plates
which connect the partitions together, and also fasten them to the end wall of
the boiler.
Fig. 7 is a cross section, and
Fig. 8 is a horizontal section, of fire tube partitions with a single undulating
tie plate.
Fig. 9 is a cross section, and
Fig. 10 is a horizontal section of a fire tube with two undulating tie plates.
Figs. 11 and 12 are cross sections of a fire tube with partition walls whose convex
surfaces are also bent or undulated.
In order to replace plain partition walls with curved walls for the foregoing
purpose, the plates must be uniformly corrugated at like distances, with parallel

page_text: projections impressed therein, so as to produce a uniform surface not only at the ends
but also lengthways, at top and bottom. For the alteration of fire tubes to this
design first the two undulated surfaces d. d¹ must be connected by means of the
screwed and cold hammered rivets e. Thereupon the half tubes are rivetted to the
partitions. Then follows the fastening of the fire-tubes to the front plates (Fig. 6)
of the boiler. Between the middle partitions, d, d' at each end an [shaped iron
plate g is inserted, during the fastening of the half round parts with the angle-iron
of the boiler frame, to protect the fire tube ends, (Fig. 1. 3. 4). The fire tubes
receive stiffening-rings h, as shewn in Fig. 5.
The firing can be effected in various ways. If the fire grate is placed before the
middle fire tubes a and b, the fire gases will first pass through these flues then through
the outside fire tubes a¹ then passing below and uniting themselves under the boiler
in the proper flue from which they pass to the chimney.
If the boiler is provided with side flues all four of the half tubes can be fired.
This increases the internal heating surface as compared with ordinary internal flue
boilers, in a very important degree.
The shaped iron stay g supports on a slope a fire brick head, as a shield against
the flame of the fire. This slope forms the ascent of the flue which commences
behind the fire grating to the fire tube passages.
The peculiar effect of the construction of the boiler consists in this, that the centre
spaces between the two rivetted curved plates form vertical heating tubes, which are
filled with water (Fig. 6) and are affected by the heat of the flues on both sides.
The same result is attained by the use of corrugated partition walls, and, it can also
be produced by the use of single undulated connecting plates between the partition
walls.
In Figs. 7 and 8 by the arrangement of the undulated tie plate between the
partitions d² 3 there is effected a stiffening of the partition as well as an extension of
the heating surface, through the increased heating tube surface.
It is likewise manifest by Figs. 9 and 10 that two undulated tie plates may-be.
employed for the same purpose, between the partition d² d³.
In the previously described construction the convex surfaces are referred to as
smooth. It is however possible to make the surface of the half tubes curved or
undulated also.
In Fig. 11 the curves i run in the direction of the periphery and in Fig. 12 they
rún in the direction of the axis of the fire tubes.
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 steam boilers with divided fire tubes.
1st. The arrangement of corrugated or undulated partitions which serve as
stiffeners, and also owing to their curves, form additional vertical heating spaces- as
herein described and set forth.
2nd. The arrangement of single or double connected curved tie plates for the
purpose of stiffening the partition walls, the curves of which plates form with the
partitions additional heating spaces.
Dated this 7th day of Lulu. 1000
.