Improvements in Tubes for Steam Boilers and in Fixing them.
Year: 1892

page_text: Date of Application, 20th June, 1892
Complete Specification Left, 27th Feb., 1893—Accepted, 1st Apr., 1893|
PROVISIONAL SPECIFICATION.
Improvements in Tubes for Steam Boilers and in Fixing them.
A communication from JOHN WHIte Boyd, M.I.M.E., Superintendent Engineer
of the Docks, Hong Kong.
I ROBERT WHITE BOYD, of 33 Bute Terrace, Glasgow, in the County of
Renfrew, North Britain, Engineer, do hereby declare the nature of this invention
to be as follows, that is to say :-
This invention has for its object the securing of steam-boiler tubes in an improved
manner, involving diminished labor and expense increased tightness with reduced
liability to leakage, facility in removing and replacing tubes, and other practical
advantages.
In carrying out the invention each tube, of steel or iron or other suitable metal,
is made with thickened ends, which are formed by welding on ferrules or rings, or
by applying end pressure to the heated metal in suitable dies. The outsides of the
thickened tube ends are carefully and accurately turned with a very slight taper;
and one end is made slightly smaller than the other externally. The tube plates
are accurately bored so that the tubes may fit them tightly, this boring operation
being by preference effected with the tube plates fixed together, so that the two
holes may be accurately in line with each other.
The tubes are fixed by being simply driven into their places with a copper
hammer or with a mallet or other convenient tool; and can be loosened when
required for removal by a stroke on the smaller ends. Some longitudinal elasticity
is by preference imparted to each tube by forming in it one or more corrugations
near each end such corrugations being externally not larger than the tube-plate
hole.
Dated this Eighteenth day of June 1809
EDMUND HUNT,
Applicant's Agent.
COMPLETE SPECIFICATION.
Improvements in Tubes for Steam Boilers and in Fixing them.
A communication from JOHN WHIte Boyd, M.I.M.E., Superintendent Engineer
of the Docks, Hong Kong.
1, ROBERT WHITE BOYD of 33, Bute Terrace, Glasgow, in the County of
Renfrew, North Britain, Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement, that is to say :-
This invention has for its object the securing of steam-boiler tubes in an improved
manner, involving diminished labor and expense, increased tightness with reduced
liability to leakage, facility in removing and replacing tubes, and other practical
advantages.
In carrying out the invention each tube, of steel, or irou, or other suitable metal,
is made with thickened ends, which are formed by welding on ferrules, or rings, or
by applying end pressure to the heated metal in suitable dies. The outsides of
the tube ends are carefully and accurately turned with a very slight taper; and
one end is made slightly smaller than the other externally. The tube plates are
accurately bored so that the tubes may fit them tightly, this boring operation being,
by preference, effected with the tube plates fixed together, so that the two holes
for each tube may be accurately in line with each other.

page_text: The tubes are fixed by being simply driven into their places with a copper
hammer, or with a mallet or other convenient tool; and can be loosened, when
required, by a stroke with the hammer or mallet on the smaller ends. Some longi-
tudinal elasticity is, by preference imparted to each tube by forming in it one or
- more corrugations round it near each end, such corrugations being externally not
larger than the tube-plate hole. The corrugations may be applied to any part of
a tube, or may extend the whole length thereof. The corrugations may be ring-like
or helical.
And in order that the said invention and the manner of performing the same
may be properly understood I hereunto append a sheet of explanatory drawings
to be hereinafter referred to and showing examples of the explanation of my
improvements.
In
The Figures, i, to 4, of the drawings represent the end portions of tubes and
parts of the tube plates, A, B, in which they are fixed. In Figures, 1, and, 3,
the tubes are in elevation and in Figures, 2, and, 4, they are in section.
Figures, 1, and, 2, the tubes, C, are shown without corrugations, whilst in
Figures, 3, and, 4, the tubes, D, are shown as made with corrugations, E, near
their ends.
In all the examples shown the tubes, C, and, D, are made with thickened
ends, F, G, these ends being formed with a slight taper externally. For tubes
of the size represented in the drawings the following dimensions of the parts
have been found to be satisfactory in practice; I do not however restrict myself
to these precise dimensions. With the tube being 3 inches externally and
2 inches internally in diameter, the thickened part at the front or smoke-box end
is made 2 inches long, 333 inches in external diameter at its outer end, and
343 inches external diameter at its inner end. At the inner or combustion-chamber
end of the tube, the thickened part is made 21 inches long, 3 inches in external
diameter at its extreme end, and 33 inches in external diameter at its inner end.
Instead of both thickening rings or collars being welded on a tube one may
be loose to allow of accurate adjustment in a boiler, the tube being fixed in such
collar after adjustment by expanding it.
With tubes and tube plates constructed and fitted as described the tubes can be
taken out for cleaning or other purposes without injuring either the tube plates or
the tubes, and the tubes can be replaced if found sound. The thickening at the
ends of the tube makes those parts less different in thickness or substance as
compared with the thickness of the tube plates than ordinary tubes, and there is
consequently less liability for differential action of changes of temperature to
cause leakage.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. Steam-boiler tubes made with thickened ends and fixed in the tube plates by
having the thickened ends slightly tapered externally and fitted into correspondingly
tapered holes in the tube plates, the parts being constructed and combined substan-
tially as and for the purposes hereinbefore described.
2. Making steam-boiler tubes such as are particularised in the first claim, with
corrugations substantially as and for the purposes hereinbefore described.
Dated this Twenty-fifth day of February 1893.
EDMUND HUNT,
Applicant's Agent.