Improvements in Incandescent Gas Lamps.
Year: 1896

page_text: Date of Application, 31st Jan., 1896
Complete Specification Left, 19th Oct.. 1896-Accepted, 2nd Jan., 1897
PROVISIONAL SPECIFICATION.
Improvements in Incandescent Gas Lamps.
We, JOHN WESTWOOD LEA, and JOHN HALL PERRINS, trading as Lea and
Perrins, of Midland Works, Bracebridge Street, Birmingham in the County of
Warwick, Chandelier, Gas and Electric Fittings Manufacturers, do hereby
declare the nature of this invention to be as follows:-
Our invention has reference to the Bunsen burners of incandescent gas lamps
and consists of the improvements in or additions to the burners of the said lamps
hereinafter described.
In order that our invention may be the better understood we remark that the
mantles used with the said burners are so fragile that with Bunsen burners of the
ordinary construction it is necessary to employ a chimney within the shade or
globe for the purpose of protecting the mantle from draught or wind. The said
cl.imneys frequently break on the lighting of the lamps the fragments of glass in
falling destroying the mantles of the said lamps.
The object of our invention is to so protect or shield the open bottom of the
shade or globe holder or gallery that draught or wind cannot enter directly into
the shade or globe the use of a chimney within the said shade or globe being
thereby rendered unnecessary.
In carrying our invention into effect we provide the globe or shade holder or
gallery of the Bunsen burner with a double cup, that is, with a cup consisting of
two concentric hemi-spherical or nearly hemi-3pherical thin metallic shells the said
cup occupying the bottom of the shade or globe holder or gallery. The two thin
metallic shells constituting the inner and outer sides of the double cup are
provided with series of holes, slots or perforations through which air may pass to
the interior of the shade or globe. The holes or slots in the outer shell are
opposite the unperforated or unslotted parts of the inner shell. We prefer to
form the slots or holes in the outer shell of the cup by forcing the metal of the
said slots or holes inwards and thereby provide the said slots or holes with inwardly
projecting tubes or flanges and to form the slots or holes of the inner shell by
forcing the metal of the said slots or holes outwards, thereby forming around the
said slots or holes outwardly projecting tubes or flanges. By this arrangement
when the two shells are put together so as to form the double cup the air entering
the globe or shade has to pass through the slots or openings in the outer shell and
over the top of the tubes or flanges around the same and then under the mouths of
the tubes or flanges of the slots or openings in the inner shell before entering the
globe or shade. By this means a very steady ascending current of air is ensured
on the outer part of the flame of the lamp and the danger of the mantle being
destroyed by draught or wind is wholly removed.
Further, by the use of the double cup hereinbefore described the air entering
the globe or shade is after a little time heated in consequence of the heating of the
metallic parts of the cup. The supply of heated air to the outer part of the
mantle results in the raising of it to a higher temperature and consequently in
increased illuminosity.
Although we have described the making of the double cups of the globe or shade

page_text: holders of metal or metallic alloy yet we wish it to be understood that they may be
made of a non-metallic material such as glass or china.
Dated this Thirty-first day of January 1896.
W. T. WHITEMAN,
Agent for the Applicants.
We, JOHN WESTWOOD LEA, and JOHN HALL PERRINS, trading as Lea and
Perrins, of Midland Works, Bracebridge Street, Birmingham, in the County
of Warwick Chandelier, Gas and Electric Fittings Manufacturers, do hereby
declare the nature of our invention and in what manner the same is to be
erformed to be particularly described and ascertained in and by the following
statement
Our invention has reference to the Bunsen burners of incandescent gas lamps
and consists of the improvements in or addition to the burners of the said lamps
hereinafter described.
In order that our invention may be the better understood we remark that the mantles
used with the said burners are so fragile that with Bunsen burners of the ordinary
construction it is necessary to employ a chimney within the shade or globe for the
purpose of protecting the mantle from draught or wind. The said chimneys
frequently break on the lighting of the lamps the fragments of glass in falling
destroying the mantles of the said lamps.
The object of our invention is to so protect or shield the open bottom of the
shade or globe holder or gallery that draught or wind cannot enter directly into
the shade or globe; the use of a chimney within the said shade or globe being
thereby rendered unnecessary.
In carrying our invention into effect we provide the globe or shade holder or
gallery of the Bunsen burner with a double cup, that is, with a cup consisting of
two concentric hemi-spherical or nearly hemi-spherical thin metallic shells, the
said cup occupying the botton. of the shade or globe holder or gallery. The two
thin n.etallic shells constituting the inner and outer sides of the double cup are
provided with series of holes, slets or perforations through which air may pass to
the interior of the shade or globe. The holes or slots in the outer shell are
opposite the unperforated or unslotted parts of the inner shell. We prefer to form
the slots or holes in the outer shell of the cup by forcing the metal of the said
slots or holes inwards and thereby provide the said slots or holes with inwardly
projecting tubes or flanges, and to form the slots or holes of the inner shell by
forcing the netal of the said slots or holes outwards, thereby forming around the
said slots or holes, outwardly projecting tubes or flanges. By this arrangement
when the two shells are put together so as to form the double cup, the air entering
the globe or shade has to pass through the slots or openings in the outer shell and
over the edges of the tubes or flanges around the same and then over the edges of
the tubes or flanges of the slots or openings in the inner shell, before entering the
globe or shade. By this means a very steady ascending current of air is ensured
on the outer part of the flame of the lamp and the danger of the mantle being
destroyed by draught or wind is wholly removed.
Figure 1 of the accompanying drawing represents in elevation a double metallic
draught preventing cup constructed according to our invention applied to an
incandescent gas lamp or burner of the ordinary construction. Figure 2 is a
vertical section through the said double cup and Figure 3 is a horizontal section of

page_text: a portion of the same, the said section being taken on the dotted line x, c
Figure 1.
Figures 4, 5 and 6 represent a glass draught preventing cup made according to
our invention as hereinafter described.
The same letters of reference indicate the same parts in the several figures of
the drawing.
We will first describe the double metallic cup Figures 1, 2 and 3.
The said cup consists of two thin sheet metallic shells marked respectively a, b
preferably connected together at their upper edges by beading the edge of the
inner shell over the edge of the outer shell a as is best seen in Figure 2. When
the cup is applied to the lamp the beaded or joined upper edges of the two
shells a,
b fit closely under the globe or shade gallery g of the lamp as seen in
Figure 1. The axial hole c in the inner shell 6 fits the upper cylindrical part of
the Bunsen burner of the lamp while the lower part of the outer ehell a fits the
lower cylindrical part or base of the said Bunsen burner. In the lower part of
the shell a is a series of holes or perforations d, d for supplying air to the air-inlet
holes of the Bunsen burner. In the upper part of the said shell a is a series of
perforations e, e through which air passes to the annular space between the two
concentric shells a, b the said air entering the globe or shade of the lamp through
holes, in the inner shell b. It will be seen by an examination of Figures 2
and 3 that the perforations in the two shells do not coincide so that direct entry of
draught or wind into the globe or shade of the lamp is prevented. In order the
better to prevent the entrance of draught or wind into the interior of the globe or
shade the edges of the perforations e in the outer shell a are turned inwards and
the edges of the perforations in the inner shell & are turned outwards (see Figure 3)
so that air entering the globe or shade takes the course indicated by the arrows 1, 1
in Figure 3.
It will thus be seen that the supply of air to the interior of the globe or shade
is controlled and that a sudden draught impinging on the cup will have but little
or no effect on the air within the globe or shade of the lamp, hence the use of a
chimney to protect the mantle of the lamp may be dispensed with.
Further by the use of the double cup hereinbefore described and represented
the air entering the globe or shade is, after the lamp has been lighted a little time,
heated in passing between the two shells of the cup in consequence of the heating
of the metallic parts of the cup. The supply of heated air to the outer part of
the mantle results in the raising of it to a higher temperature and consequently in
increased illuminosity.
We wish it to be understood that we do not limit ourselves to the shape and
position of the slots or openings e, in the two thin metallic shells a, b as the
same may be varied without departing from the nature of our invention. For
example, au outer shell a having a single row of circular or ornamental holes or
piercings near its top may be used in conjunction with an inner shell 6 having a
single row of holes or piercings near its bottom so that air entering the holes of
the outer shell a before gaining access to the interior of the globe or shade must
descend in the space between the two shells in passing to the row of holes near
the bottom of the inner shell b.
Although we have described the making of the double cups of the globe or
shade holders of metal or metallic alloy yet we wish it to be understood that they
may be made of a non-metallic material such as glass, china, mica or tale.
We will now describe the glass draught preventing cup Figures 4, 5 and 6.
The cup proper a is made of glass and of a hollow conoidal figure, that is, of a
figure somewhat resembling the outer shell of the double cup herein before
described. Figure 4 shows the said glass cup in connection with the burner and
globe or shade gallery of an ordinary incandescent gas lamp and Figure 5
represents in vertical section the said cup detached.
Figure 6 is a plan of the perforated double diaphragm of the cup hereinafter
described.

page_text: In this arrangement we make holes d in the lower part only of the cup a and use
in connection with the said cup a middle diaphragm consisting preferably of two
perforated metallic discs h, i (see Figures 5 and 6). The discs h, i are so arranged
that their perforations break joint, that is, they do not coincide as will be seen
by reference to Figure 6 and thus a baffle is provided acting essentially in the same
way as the double cup first described, the said baffle ensuring a state of quiesence
or non-disturbance of air within the globe or shade.
Although we prefer to employ a diaphragm consisting of two perforated metallic
dises as represented yet we wish it to be understood that a diaphragm consisting of
single perforated disc may be employed with nearly the same effect. Or the
diaphragm either double or single may be made of glass, china, mica or tale or
other non-metallic material.
We further wish it to be understood that the draught preventing cup last
described may be made wholly of metal instead of partly of glass and partly of
metal, or it may be made wholly of china, mica or tale or other non-metallic
material.
Having now particularly described and ascertained the nature of our inven-
tion and in what manner the sanie is to be performed we declare that we
claim as our invention of "Improvements in incandescent gas lamps" :-
First. The combination with the burner of an incandescent gas lamp of a
draught preventing cup consisting essentially of two thin concentric perforated
shells through the annular space between which shells air passes to the interior of
the globe or shade enclosing the burner, the perforations in the said shells being
non-coincident substantially as and for the purpose hereinbefore described and
illustrated in Figures 1, 2 and 3 of the accompanying drawing.
Secondly. The combination with the burner of an incandescent gas lamp of a
draught preventing cup consisting essentially of a hollow conoidal part, made
preferably of glass or other non-metallic material, the said hollow conoidal part
having near its bottom a series of air inlet holes and middle discs with non-
coincident perforations substantially as and for the purpose herein before described
and represented in Figures 4, 5 and 6 of the accompanying drawing.
Dated the 16th day of October 1896.
JOHN WESTWOOD LEA.
JOHN HALL PERRINS.