Improvements in the Construction of Furnaces and Flues for Steam Boilers.
Year: 1885

page_text: Improvements in the Construction of Furnaces and Flues for
Steam Boilers.
I DAVID PURVES of Ferro Dene, Green Lane, North Dulwich in the County of
Surrey, Engineer, do hereby declare the nature of my said invention for IMPROVE-
MENTS IN THE CONSTRUCTION OF FURNACES AND FLUES FOR STEAM BOILERS to
be as follows:-
My invention consists in constructing the cylindrical furnaces and Flues of
steam boilers of plates having solid ribs rolled on them forming when the furnace
is completed annular projecting strengthening rings. On the fire side of the furnace
plate I prefer to make at the roof of each rib an annular hollow so that the section
of iron there is substantially an equangular three armed star well filleted. Other-
wise the inner surface may be straight longitudinally without this hollow.
Furnaces and Flues constructed in this way can have the plates forming them
united by a riveted joint or by welding By this construction the longitudinal
strength is greater than in corrugated furnaces and the homogeneous strengthening
rings are less liable to crack and leak than are the usual riveted flanged
strengthening rings. The rings can be spaced further apart than, the alternate"
corrugations of corrugated furnaces or Flues and therefore the furnace crown is
less likely to harbour dangerous accumulations of scale.

page_text: °
Steam Boilers.
I DAVID PURVES of Ferro Dene, Green Lane North Dulwich in the County of
Surrey Engineer I do hereby declare the nature of my said invention for IMPROVE-
MENTS IN THE CONSTRUCTION OF FURNACES AND FLUES FOR STEAM BOILERS,
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
My invention consists in constructing the cylindrical furnaces and flues of steam
boilers of plates having solid ribs rolled on them forming when the furnace is
completed annular projecting strengthening rings. On the fire side of the furnace
plate I prefer to make at the root of each rib an annular hollow. Otherwise the
inner surface may be straight longitudinally without this hollow. Furnaces con-
structed in this way can have the plates forming them united by a riveted joint or
by welding. By this construction the longitudinal strength is greater than in
corrugated furnaces and the homogeneous strengthening rings are less liable to
crack and leak than are the usual riveted flanged strengthening rings. The rings
can be spaced further apart than the alternate corrugations of ordinary corrugated
furnaces.
In the accompanying diagrams I have sketched in figures 1 and 2 the general
forms of sections of finished rolled ribs.
Preparatorily the plates or slabs are formed with thickened bands and by one or
more rollings each thickened band is formed into a rib set up as at a, b, or other-
wise straight on the fire side as in figure 3.
The ribs are formed at such distances apart as the required strength renders
necessary.
The thickened bands are formed on the plate before the plate is bent into the
cylindrical form and the rolling of these thickenings into the rib form may be
performed either before the plate is bent or after it is in the cylindrical form and
welded.
When the junction of the ends is to be made by riveting the ribs must be
finished before the plates are bent.
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
The construction of cylindrical furnaces and flues for steam boilers with solid
strengthening rings or ribs formed on them by rolling, in the circumferential
direction, from plates or slabs having bands of increased thickness substantially
as described.
Dated this 21st day of December 1885.
DAVID PURVES.