IMPROVEMENTS IN APPARATUS FOR EXPANDING THE ENDS OF BOILER AND OTHER TUBES, AND ALSO FOR PLUGGING THE SAME WHEN REQUIRED
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by Charles Stuart and William
Walker at the Office of the Commissioners of Patents, with their
Petition, on the 11th June 1869.
We, CHARLES STUART and WILLIAM WALKER, both of Manchester, in
the County of Lancaster, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN APPARATUS FOR EXPANDING THE ENDS OF
BOILER AND OTHER TUBES, AND ALSO FOR PLUGGING THE SAME WHEN REQUIRED,"
to be as follows:-
The first part of this Invention relates to an apparatus for expanding
the ends of tubes used in multitubular boilers for the purpose of fixing
them in the holes of the tube plates with a perfect steam and water-
tight joint, but is also equally applicable to the expanding of other tubes.
Inside of a cylinder of rather smaller diameter than the tube to be
expanded I place a metallic cone, which is capable of being drawn
towards one end of the cylinder by means of a screw passing through a
screwed hole in the centre thereof. This cone as it is drawn forward
acts against and expands three slides which work in slots formed in the
said cylinder, and each carrying a small steel or hardened iron roller, so
that upon the cylinder being placed in the end of a tube and the screw

page_text: turned, the three slides with their rollers are thrust outwards beyond
the circumference of the cylinder, and expand the tube at three
equidistant points. A spanner or lever is now fitted on to a squared
part of the apparatus, and the whole is turned round on its axis, which
will have the effect of expanding the end of the tube with a rolling
motion which spreads or rolls out the fibre of the metal instead of having
a tendency to separate the fibres and split the end of the tube, as very
frequently occurs under the method usually practised of simply driving
or forcing a core into the end of the tube.
The second part of our Invention relates to a method of plugging the
ends of a boiler tube so as to prevent the fire from passing through
when either from breakage or otherwise (especially in locomotive engines
or seagoing steamers) it is desirable temporarily to close any particular
tube or tubes. In the method hitherto practised it has been usual under
such circumstances to fix a washer or disc on to each end of the tube by
means of a long bolt passing through the whole length of the tube and
secured at one end by a screwed nut. This part of our Invention
consists in fixing the washer over the end of the tube by means of a
short bolt and an expanding plug, which is easily placed in the end of
the tube, and the simple screwing up of a nut expands the plug and
fixes it inside the end of the tube, at the same time that it fixes the
washer on the end thereof. The plug is cast in two parts horizontally,
each having an inclined surface, and a screwed bolt passes through the
centre of the plug. As the bolt is screwed the nut presses the washer
forward against the tube plate, and the screw draws forward one half of
the plug and presses back the other, and as the inclined plane on one
half acts against the reverse incline on the other half it expands the
plug and wedges it tight in the interior of the tube, and a turn further
of the nut then presses the washer tight over the end of the tube, and
thus makes a perfectly steam and water tight joint.
As a modification of this Invention we propose to make the inner
sides of the two halves of the plug in the form of reversed inclined
planes, and the body of the bolt in the form of a wedge, which on being
screwed up will expand the plug equally in both directions.
A further modification consists in making the plug in three or more
sections, longitudinally, which when put together form a plug cylindrical
on the outside and with a tapering hole in the centre. The body of the
bolt is also formed taper or conical, so that on screwing up the nut

page_text: the plug is expanded equally in three or more directions without
altering the cylindrical form thereof. Instead of the expanding plug
a claw or plate of rather greater length but narrower in width than
the diameter of the tube may be hinged or jointed to the end of the
bolt. This is inserted into the tube in a diagonal position, and when
the nut is screwed up the tendency of the bolt is to draw the claw or
plate into a position at right angles to the axis of the tube, and thus to
wedge it fast and form a secure hold for the bolt.