An Improved Boiler Plug.
Year: 1890

page_text: Date of Application, 7th Nov., 1890
Complete Specification Left, 25th June, 1891-Accepted, 1st Aug., 1891
PROVISIONAL SPECIFICATION.
An Improved Boiler Plug.
We CHARLES RIX JEYES, Civil Engineer, of 16 Oxford Terrace, New Swindon,
Wiltshire, and HENRY CLAPHAM, Boilermaker, of 12 William Street, New
Swindon, Wiltshire do hereby declare the nature of this invention to be as
follows: :-
This invention has for its object an improved boiler plug which is fixed to the
top of fireboxes to boilers and which gives notice to engine drivers when the water
in the boiler is below the top of the firebox by the lead in the plug melting thereby
leaving a passage through which the steam rushes and extinguishes the fire.
We propose to construct in brass or other suitable metal an inner and outer
cylindrical cone, the outer cone of which screws to boiler & becomes a fixture.
The inner cone is hollowed out at top to receive a piece of lead which has the form
of a cylindrical prism and which when the inner cone is screwed to the outer cone
fits like a wedge and forms a steam and watertight joint.
On the bottom of inner cone is formed a nut by which the said cone is screwed
or unscrewed to the outer cone.
Dated this 6th day of November 1890.
CHARLES RIX JEYES.
HENRY CLAPHAM.
COMPLETE SPECIFICATION.
An Improved Boiler Plug.
We, CHARLES RIX JEYES, of Bradley House, Park Lane Civil Engineer, and
HENRY CLAPHAM, of 12 William Street Boiler Maker, both of New Swindon, in
the County of Wiltshire, 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 :-
Our invention relates to an improved fusible boiler plug, to be fixed in the top,
or crown of the firebox of a steam boiler, the object of which is that, notice, or
warning may be given to the engine driver, stoker, or other attendant in charge,
when the water in the boiler falls below the top of the firebox, said warning being
produced by the melting of a leaden block in the top of our improved plug whereby
the steam is permitted to enter the fire box through the passage thus left, and so
extinguish the fire, and prevent explosion.
The said boiler plug according to our invention consists of two metallic cylinders
the larger of which is of conical form internally, the smaller one being of conical
form externally, the latter fitting within the former by means of a suitable screw
thread formed on each. The larger cylinder is provided with an external screw
thread by which it may screwed into an internally threaded hole in the crown
of the firebox. A conical leaden prism is arranged to fit the smallest end of the
orifice in the outer cylinder and is held in position by the smallest end of the inner
cylinder, thus forming a steam and watertight joint.
In order that our invention and its manner of operation may be clearly understood,
we have appended the accompanying sheet of drawings, in which
Fig. 1 is a vertical section of the outer cylinder.
Fig. 2 is an outside view of the inner cylinder, and leaden prism, or plug.
Fig. 3 shews the manner in which Fig. 2 and the leaden plug fits into Fig. 1.
Fio 4 is a plan view of Fior 3.

page_text: Fig. 5 differs from Fig. 3 only as regards the shape and size of the leaden
prism, or plug, and the consequent formation of the inner cylinder to fit thereto.
Fig. 6 is a plan view of Fig. 5.
In carrying our invention into effect we construct of any suitable metal, or
alloy of metals, but preferably of brass, an outer cylinder A Fig. 1, formed as
shewn, and provided with an external screw thread a, and an internal similar
thread b, and an external flange c to receive a spanner, an internal conical shaped
cylinder B, provided with an external thread d, corresponding to b, and an outside
flange e similar to c fits and screws into the conical interior of A. A circular
conical solid leaden plug, or prism C, the shape of which in cross section may be
either as that shewn at Figs. 2 and 3, or as at Fig. 5, is first placed within A until
it occupies the position shewn by Figs. 3 and 5, blocking up the smallest end of
the conical shaped interior of A, the inner cylinder B is then screwed into A,
until it presses upon C and forces it partly through the end of A as shewn, thus
forming a perfect steam and water tight seal in the smaller end of A. The upper
end of B is cupped to fit the formation of C, as at Figs. 2, and 3, or further
cupped to suit the same when formed as at C Fig. 5, whichever type of plug may
he employed. The whole is then screwed into a suitable hole in the crown of the
firebox of the boiler, and by reason of the hollow interior of B, one exposed
surface of C, is always in contact with the water in the boiler, the opposite surface
to that of the flame of the fire, and so long as the water in the boiler covers the
top of the firebox, and the plug C, a perfect seal is maintained, but the instant
the water in the boiler is too low to cover C, the same is melted by the intense
heat from the furnace and the steam passes through B into the furnace and
extinguished the fire, thus preventing the explosion of the boiler by giving warning
to the attendant before the whole of the water is evaporated.
To renew the plug C, all that is necessary is to remove the inner coned cylinder B,
place the new plug in position, and screw home the cylinder B as before.
The upper surface of B being cupped as described permits the whole of the
melted plug to pass through B, so that no particle remains adhering to B when
cold.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is.
1st. In an improved boiler plug, the construction and use of the inner and outer
coned cylinders, and leaden plug herein described combined and operating in the
manner set forth substantially as and for the purposes named.
2nd. In an improved boiler plug, the employment of an outer cylinder A, with
external thread a, and internal thread b, receiving and holding a leaden plug C,
kept in position by an internal conical cylinder B, screwed into A, by its external
thread d substantially as and for the purposes herein described and shewn by the
appended drawings.
Dated this 25th day of June 1891.
GEO. THOS. HYDE,
4, Moorfields, London, E.C., Agent for the Applicants.