Improvements in or relating to Electric Are Lamps.
Year: 1898

page_text: Improvements in or relating to Electric Are Lamps.
I, FREDERICK BROWN, Electrician, of Highgate Road, Walsall, in the County
of Stafford, do hereby declare the nature of this invention to be as follows:-
This invention pertains to electric arc lamps, and is designed for the purpose
of rendering the said lamps safe in places where combustible gases are being dis-
charged into or form part of the atmosphere or in places where combustable dust
or flyings are present.
Hitherto a serious objection has been raised to the use of arc lamps for the
purpose of illuminating factories and other places where combustible gases and
combustable dust or flyings are constantly floating around, in consequence of the
risk of explosions should the globe enclosing the carbons and the arc be broken
either by a blow or a fall, and so expose the naked flame.
and
According to this invention this objection is overruled, as the arc lamp is con-
structed in such a manner that, immediately a globe is broken, the light is
extinguished by an interruption in the electrical circuit, operated either directly
or indirectly by the breaking of the globe. In carrying out the invention the arc
lamp is provided and fitted with two globes, an inner one and an outer one, and
these are arranged one inside the other so as to leave a space between them; the
said space either comprehending a portion of the exterior globe cir-
cumference or the whole of it. The exterior globe is connected to
carried by the lamp framework, and, .according to one form of the invention,
within this is placed a liquid within and upon which rests and floats the inner
globe; so that practically the inner globe is a floating one and carried by the
outer. This inner globe is so arranged within the outer one, and so provided
with metallic fittings, that when in its normal or floating position it is within
the electrical circuit of the lamp, but when not floating, or when displaced, is
out of the electrical circuit; so that practically it constitutes a switch. The
floating globe is so arranged within the electrical circuit that it will break the
said circuit automatically should the outer or inner globe be broken and the
liquid liberated.
In another form of this invention the liquid switch may be arranged in con-
nection with the globe or the globes, which leaves the circuit by the liquid flowing
away when the globe or the exterior globe is broken.
In another form of this invention the space between the globes may be filled
with compressed air, which operates and controls, either directly or indirectly,
a switch or contact piece disposed somewhere within the electrical circuit, the
arrangement being that so long as the exterior globe remains unbroken the
current is free to pass, but immediately the said globe is broken the current is
interrupted or shunted.
Thus
any
it is arranged that if at
time the globe, if one is
used or the exterior or inner globe, if two are used, which is preferable

page_text: becomes broken or cracked, by receiving a blow or in consequence of
the lamp falling, the electric current is, either directly or indirectly through the
means described, broken, interrupted or shunted from the carbons, which of course
immediately extinguishes the flame.
1000
Improvements in or relating to Electric Arc Lamps.
I, FREDERICK BROWN, Electrician, of Highgate Road, Walsall, in the County
of Stafford, 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:-
This invention refers to electric arc lamps, and is characterised by a means for
rendering such lamps safe for use in such places where combustible gases forin part
of the atmosphere, or in places where combustible dust or suspended matter is
flying about in the atmosphere.
Hitherto in such places as defined the use of arc lamps has been condemned, in
consequence of the risk of explosions if the globe surrounding the arc and enclos-
ing the carbons should become in any way broken and the naked flame exposed.
This, in particular, is so, as effecting the insurance of a factory or a building
where combustible gases or dust forms part of the atmosphere.
According to this invention an arc lamp is constructed in such a manner that
immediately its globe is broken or fractured sufficient to admit of the passage of
the atmosphere through its walls, the flame of the arc is automatically extinguished
by an interruption in the electrical circuit, brought about by the fact of the globe
being broken or fractured.
In the accompanying sheet of drawings the invention is carried into effect
in three ways, Fig. 1, representing an arc lamp flame protected by two globes, one
of which is a floating one in a suitable liquid, Fig. 2 representing a single globe
enclosing the arc lamp flame, and which is open to the body of the arc lamp,
containing compressed air for operating an electrical contact for making and
breaking the circuit, and Fig. 3 representing a similar arrangement of the invention
as in Fig. 2, but with two globes, between which is forced air under pressure,
which controls a suitable contact for making, and breaking the circuit; the body
of the arc lamp in this case being shut off from the compressed air, so that, prac-
tically, the globe is indirectly a safety switch and controls the current.
With reference to Fig. 1 a, c, are two globes, one of which is arranged inside
the other so as to leave a space d between them. The exterior globe a is connected
and carried by the lamp framework a², and within it is placed a liquid within and
upon which rests and floats the inner glabe c, so that practically the said inner
globe is a floating one carried by the outer globe. This inner globe c has upon
its crown part contact pieces 3, 3, which are adapted when the globe c floats
to make contact between two terminals c, e², of the electrical circuit of the series
coil, but to break the said contact immediately the said globe is lowered, displaced,
or ceases to float, by reason of the liquid supporting it escaping in any degree
by fracture or break of either of the two globes.
The inner globe c may be supported, if necessary, by sensitive yielding sup-
ports such as g, and the liquid between the two globes may be constantly changed

page_text: by connecting to the space d between them water supply and outlet pipes h, h;
the last named in order to keep constant the temperature of the liquid.
In Fig. 2 a single globe a is used to surround the carbons and the naked flame,
and this is fixed to the base a² of the lamp air-tight. The interior d of this
globe is in communication with the inside a³ of the lamp body, which is rendered
air-tight by a tightly fitting casing a¹, and is also in communication with the
head c of a piston-like part which works within a suitable cylinder or casing c³
made air-tight with the crown of the lamp's body. The end of this piston-like
part is adapted, when the interior d of the globe and inside a³ of the lamp
body contains air under pressure, to be forced into contact with the conducting
centre of a yielding diaphragm e of insulating material, which said centre is in
connection with the wire e leading from one of the terminals of the electric
current; a spring intervening between the said diaphragm and centre and a
cap or cover e enclosing it. This spring and yielding diaphragm is for the pur-
pose of allowing compensating movement of the piston-like part c³, in the direc-
tion of the arrow, for the expansion of the air within the globe and casing of the
arc lamp, by reason of the said air becoming heated from the flame at the carbon's
points. The current passes from the piston-like part through the casings c
and a to the positive carbon, and from the negative carbon to the negative ter-
minal (not shown) which is situate at the back of the casing e, and which is
connected up to the negative wire e²; electro magnets being coupled up in the
circuit as ordinarily.
In Fig. 3 two globes a, m, are connected air-tight one inside the other to the
base a² of the lamp's frame, and compressed air is contained within the space d
between them and communicates, by a tube d² running vertically through the body.
casing of the lamp, with a piston-like part working within a suitable casing c.
The one end of this piston-like part is connected to a rocking lever or arm c
which forms the connecting medium between the terminal e and the casing c,
which latter is connected up in a suitable manner to the negative carbon, and
so long as this lever is in contact with the part g of the terminal, by reason of
the pressure of the compressed air behind the head of the piston-like part, the
said terminale is connected to the negative carbon through the said lever and
the parts and c. The casing is only a carrying means and may be of
insulating material. The terminal e to which the conducting wire e³ is connected
is in contact with the body casing of the lamp and the positive carbon, and the
electro magnets are connected within the circuit in the ordinary manner.
A compensating arrangement can be fitted to the piston-like part c² to deal
with the expansion of the air in the globe d.
Suitable inflating non-return valves are fitted for pumping in the necessary
compressed air in the arrangements shown in Figs. 2 and 3, and it will be obvious
that if the pressure of the said air is relieved from the arc lamp's interior by the
fracture of the one, or one of the two of the globes, the circuit between the ter-
minals will be immediately opened.
The carbon feeding mechanism is of the ordinary construction and forms no
part of this invention.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is;
-
First. In an electric arc lamp, making the globe or globes which enclose the
naked flame at the carbons' points the medium for controlling the making and
breaking of the electrical circuit within the lamp, by the fact of it or them being
intact or sound or fractured or broken, and capable of holding or releasing a
motive power or suitable mechanism intervening between them and the said
circuit, for the purpose substantially as described.
Second. In an electric arc lamp, the combination with a suitable lamp body

page_text: containing carbon feeding mechanism, of a liquid-containing globe a fixed to the
casing of said body, a floating globe c within globe a and which carries contact
pieces and also encloses the carbons' points, and terminals e arranged in the
electrical circuit so as to make contact with the pieces c³, substantially as described
and set forth in Fig. 1.
Third. In an electric arc lamp, the combination of an air-tight body containing
the carbon's mechanism, a globe a fixed air-tight to said body and in communi-
cation with its interior, and mechanism for making and breaking contact between
the terminals e, e2, and which is brought into operation by pressure of air within
the lamp body and globe, substantially as described and set forth in Fig. 2.
Fourth. In an electric arc lamp, the combination with a lamp body part containing
the carbon feeding mechanism of globes a, m arranged one inside the other so
as to leave a space d to contain compressed air between them, and which are fixed
air-tight to the casing so as to surround the arc, and mechanism for making and
breaking connection between the terminals es, 2, and which is connected with the
space between the globes and operated by the pressure of air within said space,
substantially as described and set forth in Fig. 3.
Fifth. The general arrangement, construction, and fitting of the parts of each
arc lamp substantially as described and set forth in Fig. 1, in Fig. 2, and in Fig. 3.
Dated this 12th day of Novembar 1808
W. P. THOMPSON & Co.,
11, Burlington Chambers, New Street, Birmingham.
Also of Liverpool, London, and Manchester.
Patent Agents for the Applicant.