IMPROVEMENTS IN AND RELATING TO STEAM BOILERS
Year: 1885

page_text: I JAMES NOAH PAXMAN of the firm of Davey Paxman & Co, Engineers and
Boiler Makers Colchester in the County of Essex, do hereby declare the nature
of my invention for "IMPROVEMENTS IN AND RELATING TO 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 relates to that part of a boiler known as the flue, and consists in
joining up the various rings of which the flue is constructed in such a manner that
the flue will be expansible, that the joints will be protected from the direct
impingement of the flames and gases and that the resistance of the flue to collapse
will be materially increased.
I construct my flue of a series of solid rolled, or welded circular rings; the ends
of these rings that come together to form the joint are expanded and curved or
made bellmouthed, the one end of a slightly larger diameter than the other so that
they will form a lap joint, which is arranged so that the edge of the inner plate
faces the outlet of the flue. The joint is rivetted together in the ordinary manner.
The extent to which the ends of the rings are expanded and curved is immaterial
within certain limits, so long as the necessary amount of flexure is obtained but in
order that the joints may be protected from the direct impingement of the flames,
they should be expanded to a not less extent, so that after the joint is made a
straight edge placed along the inside of the flue across the joint will clear the rivet
heads on the inside of the joint.
In order that the nature of my invention may be clearly understood I will more
particularly describe it with the aid of the accompany drawings in which similar
parts are marked with like letters of reference.
In the accompany drawing Fig 1 shows the flue of a Cornish boiler constructed
on my improved principle. Fig 2 is an enlarged section of part of the flue showing
the expansion joint and Fig 3 shows the application of my invention to a vertical
boiler. A. A etc are the rings of which the flue is constructed, they are expanded
at their ends a and a¹ etc. the ends a being of smaller diameter than the ends
a so, that they may fit inside each other and form a lap joint, which is rivetted
together by rixets x in the ordinary manner.
In ordinary practice I do not expand the ends of the flue which are jointed to
the end plates of the boiler though it will be obvious that it is within the scope of
my invention to do so.

page_text: It will be seen that a flue constructed according to my invention may be applied
to a Cornish, Lancashire, marine or any other boiler to which an internal cylin-
drical flue is required.
Having now particularly described and ascertained the nature of my invention
and in what manner the same is to be performed I declare that what I claim is
First. The construction of flues for steam boilers as hereinbefore described and
shown by Figs 1 2 and 3 of the accompanying drawing.
Secondly. Expanding and curving the ends of the rings forming the flue as and
for the purpose described.
1885.
ROBT. ED. PHILLIPS, M.I.M.E.,
Consulting Engineer & Patent Agent,
Royal Courts Chambers,
70, 71 & 72, Chancery Lane, London, W.C.,
Agent for the Applicant.