Year: 1897

page_text: We, CHARLES MARK DORMAN and REGINALD ARTHUR SMITH, both of Ordsal
Electrical Works, Salford, in the County of Lancaster, Electrical Engineers, do
hereby declare the nature of this invention to be as follows:-
Our invention relates to cut-outs for electrical circuits in which the circuit is
broken by the fusing of a metallic wire or strip. It is frequently found necessary
to provide vents or holes in the walls of the chambers or boxes in which the cut-
outs are enclosed in order to prevent the boxes being burst by the sudden expansion
of the gases contained therein which takes place at the inoment when the fuse melts
or volatilizes. A very serious objection to these vents is that when the fuse melts
particles of molten metal and flames of incandescent gas are frequently projected
from them which are liable to set fire to surrounding objects. Our invention
consists in providing a kind of sieve or filter in connection with each vent which
catches the particles of molten metal and also cools down the vapours as they pass
out from the fuse chamber to such a temperature that there is no danger of sur-
rounding objects being ignited by them.
To carry out our invention we either fix over the holes or vents one or more layers
of fine wire gauze or other incombustible porous fabric such as asbestos cloth of
open texture, or, we provide separate chambers in connection with the vents filled
with some incombustible porous substance such as slag-wool, asbestos fibre or a
tangle or bundle of metallic wires or cuttings through which the gases escape from
the fuse chamber. In some cases instead of providing separate holes or vents we
prefer to construct the fuze chamber itself partially of wire gauze or other incom-
bustible porous fabric somewhat after the manner of a Davey safety lamp.
Dated this 10th day of September 1897.
CHARLES MARK DORMAN.
REGINALD ARTHUR SMITH.
We, CHARLES MARK DORMAN and REGINALD ARTHUR SMITH, both of Ordsall
Electrical Works, Salford, in the County of Lancaster, Electrical Engineers, 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 cut-outs for electrical circuits, in which the circuit is
broken by the fusing of a metallic wire or strip. It is frequently, found necessary

page_text: to provide vents or holes in the walls of the chambers, or boxes, in which the cut-
outs are enclosed, in order to prevent the boxes being burst, by the sudden expan-
sion of the gases contained therein, which takes place at the moment when the
fuse melts or volatilizes. A very serious objection to these vents is that when the
fuse melts, particles of molten metal and flames of incandescent gas are frequently
projected from them, which are liable to set fire to surrounding objects. Our
invention consists in providing a kind of sieve or filter in connexion with each
vent, which catches the particles of molten metal, and also cools down the vapours,
as they pass out from the fuse chamber, to such a temperature, that there is no
danger of surrounding objects being ignited by them.
To carry out our invention we either fix over the holes or vents one or more
layers of fine wire gauze or other incombustible porous fabric, such as asbestos-
cloth of open texture or, we provide separate chambers in connexion with the
vents, filled with some incombustible porous substance, such as slag wool, asbestos-
fibre, or a tangle or bundle of metallic wires, or cuttings, through which the gases
escape from the fuse chamber. In some cases instead of providing separate holes
or vents, we prefer to construct the fuse chamber itself partially of wire gauze, or
other incombustible porous fabric, somewhat after the manner of a Davey safety
lamp.
Referring to the drawings Fig. 1. is a side elevation of a rectangular single pole
fuse chamber, or box, as commonly constructed, fitted with our improved vent,
Fig. 2. is a section of the same fuse box, on the line X. X. A is the hole or vent
for the escape of gases, which in this case is made in the cover of the box, B is a
layer or layers, of incombustible porous fabric which may be conveniently held
over the vent by means of a metal ring and screws as shown. We do not confine
ourselves to this method of fixing, the fabric, across the vent holes. The fabric
may be fixed either on the inside or outside of the hole, or midway between the
inside and outside, by any method commonly in use for fixing a diaphragm in or
over an orifice. Fig. 3. is an elevation of a similar fuse box to that described in
our specification No. 13221, 1897. Fig. 4. is a section of the same on the line Y. Y.
and Fig. 5. is a section of, same on the line Z. Z. A is the hole or vent which in
this case is in the base of the fuse and forms a passage or separate chamber. Bis
a layer or layers of incombustible porous fabric fixed 'over the orifice, of the vent.
The vent or passage or chamber A is filled with an incombustible porous sub-
stance. In some cases we prefer to use the incombustible fabric over the orifice
of the vent and the incombustible porous substance contained in the vent simul-
taneously as shown in this example.
Fig. 6 is an end elevation and Fig. 7. is a side elevation of a similar fuse box
to that shown in Fig. 1. but in place of the small vent shown in Fig. 1. two
vents A. 1. A. 2. are provided which are made so large that they entirely take the
place of the ends of the cover of the fuse chamber.
These large vents are covered with one or more layers of incombustible porous
fabric, which allows free egress for the gases, but reduces their temperature as they
escape. In some cases we prefer to construct the fuse boxes with even larger areas
of vent than shown in this example. The fuse boxes shown in the drawings are
all for single pole fuses, but our improvements are equally applicable to boxes or
chambers containing double pole or multiple fuses.
Having now particularly described and ascertained the nature of our said
Invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. The addition to the vent or vents in chambers or boxes containing fusible cut-
outs, of a layer or layers of incombustible porous fabric fixed across the vent or
vents, for the purpose described in this specification.
2. The addition to the vent or vents in chambers or boxes containing fusible
cut-outs, of an incombustible porous substance, which fills the vent or vents, or fills

page_text: a passage or separate chamber, through which the gases escape from the fuse box,
for the purpose described in this specification.
3. The addition to the vent or vents in chambers or boxes containing fusible
cut-outs of both the layer or layers of incombustible porous fabric, fixed across the
vents and also the incombustible porous substance contained in the vents or
passages in connexion therewith, for the purpose described in this specification.
Dated this 30th day of November 1897.
CHARLES MARK DORMAN.
REGINALD ARTHUR SMITH.