IMPROVEMENTS IN BOILERS, FLUES, AND CYLINDRICAL VESSELS
Year: 1883

page_text: LETTERS PATENT to Herbert John Haddan, of Kensington, Middlesex, for
an Invention of IMPROVEMENTS IN BOILERS, FLUES, AND CYLINDRICAL
VESSELS communicated to him from abroad by Joseph Prégardien of Deutz,
Germany, Boiler Maker,
COMPLETE SPECIFICATION filed by the said Herbert John Haddan at the
:
IN
Office of the Commissioners of Patents on the 25th September 1883.
HERBERT JOHN HADDAN, of Kensington, Middlesex, IMPROVEMENTS
BOILERS, FLUES, AND CYLINDRICAL VESSELS communicated to me from abroad by
Joseph Prégardien of Deutz, Germany, Boiler Maker,
The invention consists in making boiler shells flues and other cylindrical vessels,
of wrought metal in such a manner, that the connecting ends of two sections are
flanged out and lap jointed to form a concave or convex circular groove, in which
the rivet-heads are countersunk as shown by the annexed drawing of various
systems of boilers.
In the boiler flues the joint is always made so that in respect to the direction of
the gases the rear end of a section fits into the front end of the next following.
The same principle is observed with regard to the shells, be the joint concave or
convex.
The flame never strikes against the edges of the plate or the rivet heads.
Fig 1 and 2 of the annexed drawing show examples of a boiler similar to a
Cornish boiler, but with a central flue below and a single shell boiler connected
with it above.
Fig 3 shows a section of a similar boiler with two flues (Lancashire system) with
Prégardien's tubes.
Fig 4 and 5 represent a Cornish boiler with one flue made after the improve-
ments.
As will be seen from Fig 1 the sections A, A, A" are made so that the front
ends B, B', B" are flanged out 3 to 5 inches (more or less according to the size of
the boiler) and in the same manner the rear edges of the sections C, C¹, Clare
flanged out but only far enough, that the external diameter on this side of a section
[Price 4ddl

page_text: fits into the internal diameter of the front end of a following section. In a similar
manner the shells of the boiler are made.
Fig 2 shows a boiler shell with concave groovees. The ends of the sections are
flanged inwardly or set in 3 to 5 inches to make a circular lap joint with a concave
groove.
The front edge of a section D, D³, D"-having regard to the direction of the
gases is set in to the proper internal diameter and the rear end of the following
section E, E, E" is set in so much only, that its external diameter fits into the
internal diameter of the preceding section.
This manner of construction has the following advantages:
1. The rivet-heads are guarded against the mechanical action of the gases.
2. The improved flanged joint strengthens the tube, without requiring special
strengthening rings.
3. This joint gives the flue and boiler shell a certain amount of elasticity in
longitudinal direction and thus there will be not so much danger of an explosion.
4. The heating gases can act better and the circulation of the water will be
improved.
5. Flues on the improved system can be conveniently fixed to ordinary Cornish or
Lancashire boilers with ordinary flues.
6. In consequence of the advantages named, a boiler made after the improved
system will be more durable.
I claim:
The making of boiler shells, boiler flues and other cylindrical vessels, which have
to resist a high internal or external pressure, in such manner that the ends of the
sections of which the boiler flue or other vessel is made, are flanged out or set in
more or less on both sides, so that the external diameter of one end is always equal
to the internal diameter of the other, and said sections set one into the other lap
jointed and rivetted together so as to form at the joints a convex or concave groove
into which the rivet heads are countersunk on that side, which is exposed to the
action of the flame.
In witness whereof I the said Herbert, John Haddan have hereunto set my hand
and seal this 25th day of September A.D. 1883.
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