Protective Shield for Safety Lamps.
Year: 1898

page_text: Date of Application, 25th Mar., 1898- Accepted, 9th July, 1898
Protective Shield for Safety Lamps.
I, GEORG ALBRECHT MEYER, of Herne, in Westphalia, Germany, Director
of Mines, 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 consists in the employment, in combination with miners safety
lamps, of a protective shield surrounding the wire gauze casing of the lamp,
which serves to keep the current of fire-damp or explosive gas mixture in mines
away from the flame, that is to say, which prevents an air current charged with
explosive gas from passing with such force through the wire gauze casing, that
the flame of body of such gases ignited within the casing, will pass out through
the meshes of the wire gauze and cause the explosion of the external fire-damp.
The said protective shield is so constructed and arranged as not to prevent the
observation of the wire gauze casing and of the flame within, and to allow of
the regulation of the air supply to the lamp, the arrangements for this purpose
being specially advantageous as compared with the protective appliances hereto-
fore proposed for protecting the lamps against rapid currents of air containing
fire-damp. These have always been subject to the disadvantages that they
either did not afford sufficient protection or did not give a sufficiently free access
for the air supply to the flame, and in addition did not allow of a sufficient observa-
tion of the formation of the aureola.
I will describe my said protective shield with reference to the accompanying
drawing, in which Figure 1 shews a side elevation of a miners safety lamp with
my improvement, Figures 2 and 3 are horizontal sections through the protective
shield in two different working positions, and Figures 4 to 7 shew modified
forms of the protective shield.
The wire gauze cylinder a, which forms the upper part of the combustion
chamber of the lamp in the usual manner, is surrounded with two cylinders A A¹
extending to the ring which is interposed between the gauze cylinder a and
the glass cylinder, and having a space between them; they are provided with
long slits b b and are rotatable relatively to each other so that in one position
the slits band 61 coincide (Figures 1 and 2), while in the other position the
slits of the one cylinder are covered by the walls of the other (Fig. 3). In
the latter position of the slits the fire-damp is effectively prevented from rushing
through the gauze cylinder with the aforesaid dangerous rapidity, while when
the slits are opposite each other as shewn in Figures 1 and 2 this safety is
diminished; but in both cases the passage for the circulation of the air remains
the same so far as its size is concerned, the current of air being merely changed
in direction, as is apparent from a comparison of Figures 2 and 3.
According to the arrangement shewn in the drawings the inner cylinder A¹
is fixed and the outer cylinder A rotatable with respect to it, and the two
positions of the slits shewn in Figures 2 and 3, as well as an intermediate position,
are secured by three stop notches c' in a key slot c in the outer cylinder A, which
notches engage with the fixed pin c³. The observation of the formation of an
aureola, which as already stated is valuable in practice since its form is an indica-
tion of the proportion of the fire-damp, is obviously only possible when the
exact form of the aureola is distinctly visible, which will be the case when the

page_text: as the
outer cylinder A is turned in the position shewn in Figure 2 as soon
appearance of the illuminating flame indicates an aureola formation; the
slits b 6 will then coincide and the interior of the gauze cylinder will be visible.
The vertical slits bb shewn in Figure 1 of the drawings may be disposed in
another direction or may have another form, thus they may be screw shaped as
in Figure 4, or horizontal as in Figure 5, or zig-zag as in Figure 6, or oblique
as in Figure 7, on the shield. Furthermore, the relative shifting of the
cylinders A A¹, which is effected by rotation in the form shewn in Figure 1,
may be effected in another direction, such as vertically, or both rotatably and
vertically, as is obvious without further drawings.
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:-
A protective shield for safety lamps consisting of two cylinders such as A A¹
surrounding the gauze cylinder of the lamp, which cylinders are provided with
slits and are moveable relatively to each other, substantially as and for the
purposes described with reference to the accompanying drawings.
Dated this 95th der of Manch 1900
ABEL & IMRAY,
Agents for the Applicant.