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

page_text: PROVISIONAL SPECIFICATION.
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 ny said invention for
IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES AND FLUES FOR STEAM
BOILERS, to be as follows:-
My invention consists in strengthening the cylindrical furnaces and flues of
steam boilers by rolling projections wholly convex externally to the cylindrical
part with plain cylindrical intervals.
To avoid having riveted seams exposed to flame, and the tendency to crack and
leak I roll a ring of V or U form on the furnace or flue tube instead of the riveted
annular strengthening ring, the ring or corrugation being wholly convex externally
and wholly concave internally. Between every two strengthening rings I make
the furnace or flue plate straight longitudinally.
These strengthening rings are formed at such distances apart as the required
strength renders necessary, with, always, a considerable length of straight interval
between every two rings. By this disposition of rings and intervals of straight
plate there are no external concavities in which the scale and dirt may accumulate
as frequently occurs in the alternately convex and concave corrugations of a
common form of furnace. In some cases one ring may be sufficient.
When these rings are to be of greater depth than can be rolled out of a plate of
uniform thickness I form the plates with thickened bands in the circumferential
direction, and when the plates are bent and welded into cylindrical flue-form the
rings are formed thereon either one or more at a time or all at one operation.
By "external" and "internal " I mean the water side and the fire side
respectively of the furnace or flue plates.
ALL

page_text: COMPLETE SPECIFICATION.
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 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 strengthening the cylindrical furnaces and flues of
steam boilers by rolling projections wholly convex externally to the cylindrical
part with plain cylindrical intervals.
To avoid having riveted seams exposed to flame, and the tendency to crack and
leak I roll a ring of V or U form on the furnace or flue tube instead of the riveted
annular strengthening ring, the ring or corrugation being wholly convex exter-
nally and wholly concave internally. Between every two strengthening rings
I make the furnace or flue tube straight longitudinally. These strengthening
rings are formed at such distances apart as the required strength renders necessary,
with, always, a considerable length of straight interval between every two rings.
In the accompanying diagrams I have sketched in figures 1 and 2. the general
forms of sections of finished rolled rings. By this disposition of rings and intervals
of straight plate there are no external concavities in which the scale and dirt may
accumulate. In some cases one ring may be sufficient.
When these rings are to be of greater depth than can be rolled out of a plate of
uniform thickness I form the plates with thickned bands in the circumferential
direction, and when the plates are bent and welded into cylindrical flue-form the
rings are formed thereon either one or more at a time or all at one operation.
"external" and "internal" I mean the water side and the fire side
respectively of the furnace or flue plates.
By
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 rolled
strengthening rings formed on them by rolling, with plain cylindrical intervals, out
of plates of uniform thickness and from plates having thickened bands substantially
as described.