Year: 1897

page_text: I, JOHN THOMAS, Chief Engineer, Royal Mail Steamer Leinster, Kingstown,
Ireland, do hereby declare the nature of this invention to be as follows:
My invention relates to an improved stopper for leaky boiler tubes and has for
its object to provide a tube stopper which is capable of being very quickly inserted
and tightened up without encountering any of the difficulties and objections
incidental to tube stoppers such as are now used.
This improved tube stopper consists of two expansible plugs adapted to be simul-
taneously expanded so as to close the opposite ends of the tube. Each plug is
formed of a disc of india-rubber clamped between two metal discs confined upon
a central rod between a nut or head at one end and an eccentric pressure device
at the other, the plugs being separated by a distance tube through which the central
rod passes and by which thrust against the one plug is transmitted to the other.
The compression of the plug is effected by the action of a lever-operated cam pivoted
to the end of the central rod and bearing against an outer capping disc of the
adjacent plug whereby the central rod is put in tension and the distance tube into
compression with the effect that the rubber disc of each plug is squeezed between
its adjacent pair of metal discs and so expanded as to fit tightly in the tube into
which the stopper has been previously inserted.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
I, JOHN THOMAS, Chief Engineer, Royal Mail Steamer Leinster, Kingstown,
Ireland, 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:-
My invention relates to an improved stopper for leaky boiler tubes and has for
its object to provide a tube stopper which is capable of being very quickly inserted
and tightened up without encountering any of the difficulties and objections
incidental to tube stoppers such as are now used.
The difficulties experienced in fixing a tube stopper of the ordinary kind are
that in the first place it is necessary to let down the steam pressure considerably
before the tube stopper can be entered, and when inserted it is necessary to hold

page_text: on to the outer end of the rod with a wrench to keep the rod from turning whilst
screwing up the nut to put compression on the rubber washers, the operation
requiring about fifteen or twenty minutes to effect and being attended with con-
siderable danger in consequence of the unavoidable proximity of the workman to
the leaky tube whilst screwing up and the loss of time whilst the tube door is open.
With the improved stopper of this invention it is not necessary to let down the
steam pressure, all that is required being to open the tube door, to push in the
stopper, and to apply the compression by the special means hereafter described,
an operation which can be performed in less than a minute.
The improved tube stopper of my invention is illustrated in the accompanying
drawings forming part of this specification and will be described with reference
thereto, Figure 1 being a longitudinal section of the tube stopper represented in
situ within a tube (the middle portion being broken out in order to contract the
length of the view) and Figure 2 being an end view.
It consists essentially of two expansible plugs (A, B) and of means of applying
compression thereto whereby they may be simultaneously expanded so as to close
the opposite ends of the tube. Each plug is formed of a thick disc of india-
rubber (a) clamped between two loosely fitting metal discs (b, b) all three dises
being slipped upon a central rod (C) and being confined between a nut or head (D)
at the one end and an eccentric cam (E) at the other, the plugs being separated
by a distance tube (F) through which the central rod (C) passes and by which
thrust against the one plug is transmitted to the other. The cam (E) by which
the compression of the plugs is effected is constituted by a pair of eccentric discs
formed on the forked head of a lever (G) and pivoted at (9) to a corresponding ear
formed on the end of the central rod (C) the eccentric discs bearing against an
outer capping disc (H) loose on the rod (C) and adjacent to the plug (A) the said
disc being of a size to bear against the end of the tube (I) to be stopped. When
the tube stopper has been inserted in the tube to be stopped, the lever handle (G)
being in alignment with the central rod, all that is necessary is to turn down the
lever handle so that by the action of the eccentric cam (E) upon the capping
disc (H) the central rod (C) will be put in tension and the thrust tube (F) into com-
pression with the effect that the rubber disc (a) of each plug is squeezed between
its adjacent pair of metal discs (b) and so expanded as to fit tightly in the tube I
and also upon the rod C.
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:
A tube stopper constructed of a pair of longitudinally compressible and radially
expansible plugs formed of rubber and metal discs, in combination with a central
tension rod, a thrust tube thereon between the plugs and a lever operated eccentric
cam pivoted to the central rod and adapted to apply tension to the rod and thrust
to the tube so as to put the plugs simultaneously into compression substantially as
specified.
Dated this 28th day of February 1200
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.