Improvement in Cylindrical Boilers.
Year: 1891

page_text: ate of Application, 3rd Sept., 1891-Accepted, 9th Jan., 1892
COMPLETE SPECIFICATION.
Improvement in Cylindrical Boilers.
I GEORGE BARKER of 77 Colmore Row, Birmingham in the County of Warwick
Consulting Engineer, do hereby declare the nature of the said invention as com-
municated to me from abroad by Walter Scott Shipe of the City of Toronto in the
County of York, in the Province of Ontario, Canada, Mechanic, and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement. :-
The object of the invention is to produce a cylindrical boiler which will have a
smooth exterior surface capable of being polished and it consists essentially of a
sheet metal cylinder with its longitudinal joint formed by a metal strip located on
the inside of the cylinder and having a rib which projects outside and is rivetted or
flanged over the joint so as to form a solid steam-tight joint, the outer surface of which
shall be substantially flush with the outer circumference of the cylinder, the ends
of which are closed by heads shrunk or compressed in position.
Figure 1, is a sectional elevation of my improved boiler.
Figure 2, is an enlarged sectional detail, showing an improved plan for securing
the heads of the boiler in position.
Figure 3, is an enlarged cross-section showing a plan of the longitudinal joint.
Figure 4, is an enlarged cross section of the strip used in forming the longitudinal
joint.
Hitherto hot-water-boilers used in connection with a cooking stove or other
heater have had their longitudinal joint formed by the edges of the sheet over-
lapping each other and rivetted together, the heads of the boiler being likewise
rivetted, consequently the outer surface of the boiler was covered with ugly pro-
jecting rivets which effectually prevented the boiler receiving a high polish or finish.
By the adoption of my invention it is possible to produce a boiler with practically
a smooth outer surface which may be highly polished or nickel plated if desired,
while at the same time a very strong boiler is secured at a less cost than the old
style referred to.
A represents the metal sheet forming the cylinder. The edges a of the longitu-
dinal joint of the cylinder (see Figure 3) are bent inwardly as indicated to fit the
recess made in the strip B as shewn in Figure 4. This strip as it will be seen
on reference to this Figure, has a rib C which projects between the edges a and is
rivetted or compressed down as shewn in Figure 3 so as to over-lap the edges a and
fill the depression formed by the bending of the edges a, and in this way make a
practically invisible joint which will at the same time be very strong.
It will be noticed that the edges d of the strip B are bevilled off so as to leave a
small recess between the strip and the shell of the cylinder A. When the interior
of the cylinder A, is galvanized or otherwise protected the cylinder is turned so
that the said material will flow into the said recesses thus forming a seal on each side
of the strip B.
It will be observed that there is a bead D rolled round the cylinder A, near each end.
A similar bead is rolled in the head E. Each head is made the proper size to fit over
the end of the cylinder A and before placing it in position I heat it so that it will slip
on easily until the bead in the head E fits over the bead D made in the cylinder A
as indicated by Figure 2. The head is then cooled causing it to shrink and grasp
the cylinder. Instead of, or in addition to, this shrinking process I place the
cylinder with its head in a powerful machine and compress it firmly in position.
Each end of the cylinder A is bent slightly inward so as to form a recess into which
the galvanizing or other protecting material flows forming an inner seal between the
cylinder and its head. The edge of the head E is bent outwardly so as to leave a

page_text: recess into which the galvanizing or other material may be caused to flow & form
an outer seal between the cylinder and its head.
In order to form a simple cheap and effective joint between the boiler and its
connections, I stamp each hole made in the boiler so as to force the material
inwardly and form an inner flange.which. I screw so as to receive the end of the
pipe or its coupling.
With the view of enabling the boiler to be made out of light material, I insert in
the bead D a stiff metal ring D'. This strengthens the boiler at the point where
the annular joint is made, and permits the use of light material in the construction
of the boiler.
In my construction of the longitudinal joint the sheet metal is bent inwardly or
towards the centre of the boiler and the bent edges are set in grooves formed in the
heaviest part of the strip forming a channel in which the solid rib is swaged or
spread laterally under a powerful pressure which not only makes the outside of the
joint substantially or quite flush with the sheet, but compresses the metal in much
less-space than when in its original form and has been found by actual experiment
to be capable of bearing great strain. This is a great advantage for these boilers
have to bear an immense pressure, in some situations and a mere bending of the
flange over the curved edge is not sufficient to stand the strain even if the flanges
were not weakened by said bending as must undoubtedly be the case. Besides this
I have a further advantage in setting on the head which could not be put on water-
tight in a way that would be commercially practicable when there is an outside or
projecting rib.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
-:
1st: A sheet metal boiler having a longitudinal joint formed by the edges of the
sheet metal which are to be united of a uniting strip of solid metal the edges of the
sheet metal being bent inwardly and the strip having grooves to receive them and a
rib to be rivetted or forced into the space between the said edges and composed of
sufficient metal to substantially fill the said space, substantially as and for the
purpose specified.
2nd A sheet metal boiler having its longitudinal joint formed by the edges of
the metal bent inwardly on a compound angle in combination with a metal strip
having a solid rib with grooves on each side to receive the inwardly set edges of the
plate said rib being flattened out and filling the space between the angles of the
sheet metal plate leaving the outside of the cylinder substantially smooth sub-
stantially as and for the purpose specified.
3rd: A sheet metal boiler having a bead D rolled in it near its end in combina-
tion with a head E having a corresponding bead rolled in it to fit onto the bead D
substantially as and for the purpose specified.
4th A sheet metal boiler having a bead D rolled in it near its end the end edge
being bent slightly inwardly in combination with the head E having a corresponding
bead rolled in it to fit onto the bead D and its edge bent inwardly substantially as
and for the purpose specified.
5th: A sheet metal boiler having a hole punched in it near one end in such a
manner that the stock from the hole shall form an annular flange substantially as and
for the purpose specified.
6th: A sheet metal boiler having annular strengthening rings inserted in it, one
at each end, substantially as and for the purpose specified.
Dated this 2nd day of September 1801
GEORGE BARKER,
77, Colmore Row, Birmingham.