Improvements in and connected with Water Tube Steam Generators.
Year: 1897

page_text: Date of Application, 13th Dec., 1897-Accepted, 29th Jan., 1898.
COMPLETE SPECIFICATION.
Improvements in and connected with Water Tube Steam Generators.
I, GUSTAV DÜRR, Manufacturer, of Grafenbergchaussee, Düsseldorf, in the
German Empire, 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:-
Tubular steam generators in which water tubes are situated directly over the
furnace or combustion chamber have the defect, that the heating gases strike the cold
tubes, before they have attained their maximum temperature, or maximum heating
capacity, and that consequently the combustion is irregular and less heat is
transmitted to the tubes, than would be the case in a rationally constructed boiler.
Moreover, a considerable portion of the gases escape on the shortest way, without
intimately touching the tubes.
To avoid these defects, I place between the tubes of the lowest row, slabs or blocks
of stone, earthenware or similar material, so as to bridge over the gaps between the
said tubes and leave a suitable number of openings for the passage of the heating
gases.
In the accompanying drawings
Fig. 1 is a cross section through the furnace of a water tube boiler embodying my
invention; Fig. 2 is a longitudinal section of the same; Figs. 3 to 7 are detail views
of the blocks or slabs on a larger scale.
The slabs or blocks e, together with the lowest row of tubes, form the roof of the
combustion chamber, which is thus closed as far as practicable, in order to obtain a
more complete combustion and greater development of heat.
The openings formed in the roof guide the heating gases in such a manner, that
they impinge directly against the tubes of the second or of the third row. The latter
case is represented by the drawings, the heating gases being led upward between the
tubes of the second row, so as to avoid injury to the same. The said slabs may have
various sizes and shapes, some of which are shown by the drawing. The holes or
recesses may be formed in the middle of the blocks, as represented by Figs. 3 and 4,
or at the sides, as represented by Figs. 5, 6 and 7. The sides of the blocks are
shaped so as to follow the curvature of the tubes.
Instead of cutting the blocks which form the roof, from natural stones, they may
be moulded from earthenware, stoneware, or any suitable fireproof composition. Such
a roof may be formed not only over the fire grate or furnace, but also over a portion
of the heating flues.
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:
1. In steam generators, a furnace or flue having a roof formed by inserting between
the water tubes of the lowest row suitably shaped blocks of stone, earthenware, or
similar material, provided with openings or recesses for the heating gases, substantially
as described and for the purpose specified.

page_text: 2. A steam generator having a row of water tubes and intermediate blocks of
stone or earthenware, perforated or recessed for the passage of the heating gases,
the whole being so arranged as to form the roof of the combustion chamber,
substantially as described and for the purpose specified.
Dated this 13th day of December 1897.
FAIRFAX & WETTER,
Patent Agents, 37 and 39, Essex Street, Strand, London.