IMPROVEMENTS IN MINERS SAFETY LAMPS
Year: 1885

page_text: I JOHN CLARK JEFFERSON of 2 East Parade Leeds in the County of York
engineer and Patent Agent do hereby declare the nature of said Invention for
IMPROVEMENTS IN MINERS SAFETY LAMPS to be as follows:-
The object of my Improvements is to render Miners Safety Lamps constructed
in accordance with my Invention safer than those now in use.
My Improvements refer to the wire gauze on which in the first instance the
safety of a miners lamp depends, and such improvements are applicable to all kinds
of miners safety lamps now in general use.
The action of the wire gauze of a safety lamp is to prevent the passage of flame
through such ganze by reducing the temperature of any gases escaping through
the gauze, below that necessary for the ignition of the mixture of gas and air.
Now my Improvement has for its object the increasing of the cooling or
conducting surface of the gauze. This I effect by corrugating the wire gauze; the
vertical or cylindrical portion of the gauze having preferably vertical corrugations,
and the horizontal or circular portions of the gauze having circular or annular
corrugations.
This improvement may be used instead of, or in addition to the plain gauze as
now used in miners' lamps.

page_text: I JOHN CLARK JEFFERSON of 2 East Parade Leeds in the County of York
engineer and Patent agent do hereby declare the nature of said invention for
IMPROVEMENTS IN MINERS SAFETY LAMPS and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
The object of my Invention is to render Miners Safety Lamps safer than those
now in use..
My Improvements refer to the wire gauze. on which in the first instance the
safety of a miners lamp depends, such improvements being applicable to all kinds
of safety lamps now in general use. The action of the wire gauze of safety lamps
is to prevent the passage of flame through such gauze, by reducing the temperature
of any gases escaping through the gauze below that necessary for the ignition of
the mixture of gas and air.
Now my Invention has for its object the increasing of the cooling or conducting
surface of the gauze. This I effect by corrugating or fluting the wire gauze, the
vertical or cylindrical portion of the gauze having preferably vertical corrugations,
and the horizontal or circular portion of the gauze may have circular or annular
corrugations.
These improvements may be used instead of, or in addition to the plain gauze as
now used in lamps.
And in order that my Invention may be more clearly and completely under-
stood, reference is given to the accompanying drawings and to the letters and
marks thereon.
Fig. 1 is a sectional elevation of my Improvements applied to a Clanny Safety
Lamp, and Fig. 4 is a plan of same on line A B Fig. 1.
Fig. 2 is a sectional elevation of my Improvements applied to a Mueseler Safety
Lamp, and Fig. 5 is a sectional plan of same on line C D Fig. 2.
Fig. 3 is a plan of the cap d and is common to both Figs. 1 and 2.
a represents the corrugated or fluted wire gauze, which is the main or essential
part of my Invention.
b and c are asbestos or rubber packing rings, fitting in grooves in the cap d and
the ring e respectively, and serve to make the joints with the gauze flame- or
air-tight.
In the case of the Mueseler Lamp, see Fig. 2, h is a similar asbestos or rubber
ring for keeping the joint between the glass and the underside of the horizontal
gauze flame- or air-tight. Or by altering the shape of the ring e, the horizontal
gauze may be placed between the rings c and e, and the ring h entirely dispensed
with.
It will be seen (by measurement) that the corrugated wire gauze represented in
Figs. 1 and 4 has three and one half times the cooling surface of a plain gauze of
the same internal diameter, whilst in the case of the Mueseler Lamp shewn in
Figs. 2 and 5, the ratio is four and one third times. It will be evident that this
proportion can be varied, by increasing or decreasing the number or depth of the
corrugations.

page_text: By preference I make the top cap d closed, and to project some distance above
the gauze, so as to form a chamber. The air contained within this chamber acts
as a cushion in case of an explosion of fire-damp within the lamp. In such a
construction of safety lamp shewn in Figs. 1 and 2, the horizontal top gauze,
(which is one of if not the weakest part of a safety lamp,) is dispensed with; and
the heated products of combustion escape through the upper part of the corrugated
wire gauze.
Owing to the very much greater surface passed over by the heated products of
combustion in a lanp constructed in accordance with my Invention, the gauze is
heated to a much less degree than the horizontal top gauze of any ordinary safety
lamp, and being at a much lower temperature is capable of resisting more
effectually the passage of flame through it.
By forming the flange fas shewn in dotted lines Figs. 4 and 5, and the flange
of the cap d as shewn by the dotted lines in Fig. 3, the lamp may be protected
from currents of excessive velocity by passing a conical or cylindrical shield n over
the flanges; although I find that my Invention of a corrugated gauze is in itself a
great protection against any air current usually met with in mines.
.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed; I declare that what
I claim is
In Miners Safety Lamps
1. The use of a corrugated or fluted wire gauze a substantially as herein set
forth and shewn in the accompanying drawings.
2. The arrangement and combination of a corrugated or fluted wire gauze a,
closed cap d, and ring e, substantially as herein set forth and shewn in the
accompanying drawings.
3. The use of a hollow closed cap d substantially as and for the purposes herein
set forth.