IMPROVEMENTS IN MINERS' 'SAFETY LAMPS
Year: 1867

page_text: PROVISIONAL SPECIFICATION left by Thomas Story Horn at the Office
of the Commissioners of Patents, with his Petition, on the 28th
November 1867..
I, THOMAS STORY HORN, of Newcastle-upon-Tyne, Agent, do hereby declare.
the nature of the said Invention for "IMPROVEMENTS IN MINERS' 'SAFETY
LAMPS," to be as follows:-
This Invention relates to a means of obtaining an increased amount of light-
and more perfect combustion in miners' safety lamps than has hitherto been
obtained, whereby little- or no unconsumed carbon or soot is deposited in or
upon the lamp,-add the lamp is rendered moreover thoroughly inexplosive, and.
the light is immediately extinguished should the lamp by accident or otherwise.
be overturned.
This Invention has reference also to an improved look for fastening all
the parts of the improved lamp together. In constructing a safety lamp:
according to this Invention the base of the lamp forms the receptacle for the.
oil, having a tube in the centre for the insertion of the wick or lamp cotton
and for feeding or supplying the lamp with oil. Above this receptacle and
permanently attached to it there is an air chamber perforated round the
circumference for the admission of air horizontally at a point below-the point
of combustion. The top plate of this air chamber is also perforated with very

page_text: fine holes for the admission of the air to a combustion chamber which surrounds
the wick, and is formed of metal of a dome or other shape, having an aperture
at the summit through which the wick can pass. This metal dome is fitted by
a bayonet joint, screw, or other means into a metal ring er flange, which flange
has formed on its outer or upper surface an annular groove for the reception
of a glass ehimney which is cemented therein. By the use of the dome the
air for supporting combustion passing through the air chamber from below
impinges on the flame at the point of combustion, rendering such combustion
more complete and therefore affording increased light. The dome also acts
as an extinguisher should the lamp be either overturned by accident or other-
wise, the light in that case immediately dying out. The products of combustion
pass up the glass chimney through a contracted aperture in a metal cone fitted
thereon, and becomes diffused by escaping through small perforations in a
copper cap fitting on the glass chimney. This cap and also the dome may be
readily removed when necessary for the purpose of cleaning the glass chimney.
A guard of metal or other suitable material may if desired surround the
apertures in the circumference of the air chamber, and serve as a protection
against any sudden gust, blow, or outburst of gas or air interfering with the
steadiness of the light. As a protection to the glass chimney from breakage,
a wire cage is placed on the exterior so as to surround the same. With a
view to locking the lamp there is drilled in the top rim and bottom flange an
aperture which extends also into the solid part of the side of the air chamber,
the drilling being of course in a line so as to admit of a steel red passing
through from top to bottom. On the top rim there is rivetted a metal
tongue which is bored to admit of a screw bolt, and on the top cover
there is rivetted another and larger piece of metal having a slit for the passage
of the former piece, this larger piece being also bored partially through for
the passage of the said screw bolt. This bolt is so fixed as not to be capable
of entire withdrawal. On bringing the cover down, the metal tongue enters
the foek on the cover, and the bolt is then screwed by a key through both
pieces, thereby locking the lamp; the cover by covering the head of the steel
rod keeps it in place, and the lower end of the steel rod by passing through
the lower flange into the solid piece below prevents the base from being
unscrewed.