Improvements in the Manufacture of Mantles or Incandescing Bodies. for Incandescent Gas Lamps.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Mantles or Incandescing Bodies.
for Incandescent Gas Lamps.
1, JOHN FREDERICK DUKE of 160 Rosendale Road, West Dulwich in the
County of London, Chemist, do hereby declare the nature of this invention to be
as follows:-
My invention has reference to the manufacture of mantles or incandescing
bodies (hereinafter included in the term "mantles ") for incandescent gas lamps
and its objects are chiefly to render the mantles more durable, to increase their
lighting power, and to obviate the greenish color which generally shows itself in
mantles after they have been in use some time.
According to my invention I immerse the mantles in or impregnate them with
a substance which if the mantles are afterwards submitted to a high temperature
will have the effect of fusing the material of the mantles or of becoming fused
among the particles of the material of the mantles, and thereby making them of a
more homogeneous texture; that is to say I first immerse the mantles in or
impregnate them with a substance such as described and then submit them to the
requisite high temperature.
A substance which I have found to answer the purpose of my invention is
chloride of barium.
The manner in which my invention may be carried out by means of chloride of
barium is as follows:-I take a saturated solution of chloride of barium and dip
the mantles in it either after or before the burning out of the tulle or other fabric.
After the mantles are dry I place them on burners which I keep alight at a high
temperature for a sufficient time to produce the effect hereinbefore explained.
Dated this 20th day of June 1896.
J. C. MEW BURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.
Improvements in the Manufacture of Mantles or Incandescing Bodies.
for Incandescent Gas Lamps..
I, JOHN FREDERICK DUKE of 160 Rosendale Road, West Dulwich in the
County of London, Chemist, 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 has reference to the manufacture of mantles or incandescing
bodies (hereinafter included in the term "mantles") for incandescent gas lamps-
and its objects are chiefly to render the manties more durable, to increase their

page_text: lighting power, and to obviate the greenish color which generally shows itself in
mantles after they have been in use some time.
According to my invention I dip the mantles, preferably when they have their
usual coating of collodion in a solution of a barium salt preferably a cold saturated
solution of barium chloride. Then when the mantles are dry I submit them to a
high temperature (which may be best effected by placing them on Bunsen
burners) for a sufficient length of time to drive out the acid and thereby reduce
the barium salt to barium oxide. The heat in addition to converting the salt into
oxide upon the surface of the mantle has the effect of producing a slight fusion of
the refractory metals of the mantles or of the barium so that they become
sufficiently united for the barium oxide to be permanently retained. This union
also increases the resiliency of the mantles rendering them stronger and more
durable.
The coating of the mantles with barium oxide has the further advantage of
greatly increasing their lighting power and of obviating the tendency of the light
to acquire a greenish color in course of time. This is due to the following reason:
It is a known physical property of barium oxide to absorb oxygen from the air at
a high temperature and to give up this, oxygen at a slightly lower temperature.
When a mantle coated with barium oxide is fitted to a gas lamp in the usual
manner and the gas is ignited so that the mantle becomes incandescent, the inner
side of the mantle remains at a slightly lower temperature than the outer side
which is in contact with the atmospheric air because the gas plays or impinges
upon the inner side and tends to cool it. The result of this is that the coating of
barium oxide at the outer side absorbs oxygen from the atmospheric air, and as it
were, becomes a carrier of the oxygen from the atmospheric air outside the mantle
to the gas that impinges upon the inside of the mantle. Consequently as the gas
receives an increased supply of oxygen a higher temperature and greatly increased
light are produced.
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 :-
1. The process or method of treating mantles or incandescing bodies for
incandescent gas lamps which consists in dipping said bodies in a barium salt
preferably chloride of barium, then allowing them to dry and then submitting
them to a high temperature substantially as and for the purpose hereinbefore
described.
2. The coating of the refractory metals of mantles or incandescing bodies for
incandescent gas lamps with harium oxide substantially in the manner and for the
purpose herein before described.
Dated this 22nd day of March 1907
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.