IMPROVEMENTS IN LAMPS FOR ELECTRIC LIGHTING."
Year: 1880

page_text: LETTERS PATENT to Thomas Howard Blamires, of Huddersfield, in the County
of York, for an Invention of "IMPROVEMENTS IN LAMPS FOR ELECTRIC
LIGHTING."
PROVISIONAL SPECIFICATION left by the said Thomas Howard Blamires at
the Office of the Commissioners of Patents on the 2nd February 1880.
THOMAS HOWARD BLAMIRES, of Huddersfield, in the County of York. IMPROVE-
MENTS IN LAMPS FOR ELECTRIC LIGHTING."
"
The object of this Invention is to prevent the consumption of the carbon or other
material used in producing electric light, and this I accomplish by producing and
maintaining a vacuum in a chamber containing the carbon or other material. The
vacuum is produced by means of a column of mercury placed in a suitably formed
globe and tube, such tube being sufficiently long as to contain mercury to balance
the weight of the atmosphere, like a barometer.
One of the insulated wires connected with the carbon or other material is placed
in and through the long column of mercury, the other wire being simply dipped in
the mercury, so that an electric current is established, or two insulated wires may
be carried through the column of mercury and connected to the ordinary electric
machine. The mercury is placed in the globe and tube by any of the ordinary
methods of filling barometrical tubes, in order to form a perfect vacuum where the
carbon or other material is being used for producing electric light. The Invention
is equally applicable whether the light is produced by incandescence of the material
or by the electric arc between charcoal points.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Howard Blamires in the Great Seal Patent Office on the 31st
July 1880.
THOMAS HOWARD BLAMIRES, of Huddersfield, in the County of York. " IMPROVE-
MENTS IN LAMPS FOR ELECTRIC LIGHTING."
The object of this Invention is to prevent the consumption of the carbon or other
material used in producing electric lights, and this I accomplish by producing and
maintaining a vacuum in a chamber containing the carbon or other material.
Heretofore all attempts to produce and maintain a vacuum in electric lamps have
been unsuccessful, owing to the imperfect construction of the apparatus and the
means employed to produce the vacuum. It as been customary to pass the con-
ducting wires through the material of the lamp, and owing to the difference of
expansion between the conductors and the lamp the vacuum could not be perfectly
maintained owing to the gradual passage of air between the two materials.
According to my Invention the vacuum is produced by the employment of a
column of mercury placed in a suitably formed globe and tube, the tube being long
enough to contain a column of sufficient beight to counterbalance the pressure of the
atmosphere, similar to a barometer. As the form of apparatus may be varied con-
siderably I herein give reference to the accompanying Sheet of Drawings, which
illustrate several methods of carrying out my Invention. Fig. 1 illustrates a lamp
adapted for the consumption of carbons placed end to end. It consists of a globe
A terminating at its lower extremity in a tube B, and having at its upper extremity
a shoulder or neck C, the top or orifice being ground, so as to render it perfectly
flat. This orifice is closed by a metallic stopper D, a washer of leather or india-
rubber or other suitable luting material being placed between the metal and glass,
so as to make the joint perfectly tight; to this metallic stopper is fixed one of the
carbons E, the other carbon being passed through a glass tube G supported by suit-
able insulating material H in the widest part of the tube B. The lamp is prepared
for use as follows:-The carbon F is first placed within the glass tube G, within
which it is free to slide, and rests upon the narrow portion of the tube B. The
neck or orifice C is then closed by the stopper D and washer E, which are held
securely to their place by means of the screw cap shewn in Fig. 2. A clip or nut J
made in two halves, and having a thread formed thereon, is placed round the neck
of the globe under the shoulder, and a cap K is screwed over the same; the stopper
is then pressed firmly to its seat by means of the screw L passing through the top
of the cap.
The lamp is then inverted and filled with mercury, which passes
through holes in the insulating support H into the globe, and when both globe and
tube are full of mercury the end of the tube is closed and placed within a vessel M
containing mercury, and the lamp placed in a vertical position; the mercury will
then flow out of the globe until the column is balanced by the atmosphere, leaving
a perfect vacuum. The carbon F being lighter than the mercury floats therein, by
which means the two points are kept in contact. The cap K may now be removed,
as the atmospheric pressure upon the stopper is sufficient to make a perfectly tight
joint and prevent the admission of air. To prevent accidental disturbance however
the stopper may be covered with plaster of Paris or other suitable cement. Con-
nexion with the battery or generator is made by joining the conducting wire for
the carbon E to the metallic stopper, and by dipping the other wire into the mercury
in the vessel M. In order to prevent expansion about the neck of the globe the
same may be kept cool by forming around it a small channel or reservoir N to
contain water or mercury; also, in order to prevent the variation of atmospheric
pressure from altering the height of the column of mercury, the atmosphere may be
cut off by means of a screw plug m in the vessel M. In Fig. 3 I have shewn how
the vacuum may be maintained without the permanent use of the tube B. In this
case the globe is formed alike at both ends, but to the stopper at the bottom or

page_text: filling end is attached a soft metal pipe through which the globe is filled and the
vacuum produced, as before described. The pipe is then nipped, so as to perfectly
close the metal, and cut off a short distance below the stopper, leaving sufficient
mercury to float the carbon, if necessary to float the carbon. In Fig. 4 I have shewn a
construction of lamp for burning the Jablochkoff candle. This consists of a globe a
with a ground neck b, into which fits a hollow stopper c having two tubes d. The
"candle" e is fitted within the stopper, and a conducting wire from each carbon
passed into the tubes d. The vacuum is then produced, as before described, and
connexion made with the battery through the mercury in the vessels f, or one tube
may be employed and both wires passed through it, one wire being insulated, as
hereinafter described.
In Fig. 5 I have illustrated another form of lamp for the consumption of carbons
placed point to point, or of one carbon in contact with a metallic point. In this
case the orifice of the globe is closed by a metallic stopper a and washer c, the
stopper being hollow for supporting the lower carbon b, which passes loosely through
& glass tube d, so as to be insulated from the stopper. A continuation of the
stopper holds the second carbon or metallic point e. The stopper rests upon the
flange of the pipe g, being insulated by a washer of vulcanite or india rubber h.
Around the neck of the globe is secured a split nut K having bolts 7 fixed thereon
which passes through holes in the flange f, and by means of nuts m the apparatus is
bound firmly together. The vacuum being formed as before described contact is
made with the carbon 6 through the column of mercury, and with the carbon or
point e by connecting up to the metallic stopper at n. Fig. 6 shews a modification
of this lamp in which contact with the carbon e is effected by means of an insulated
wire ? passing down the tube; this arrangement allows the flange f to be cup-
shaped, so as to screw directly over the split nut K. It will be readily seen that
this Invention is equally applicable whether the light is produced by incandescence
of the material or by the electric arc between charcoal points. In Fig. 7 I have
illustrated a lamp of very simple construction. The lamp is first formed in two
parts separated at the dotted line a. The carbon a of horse shoe form is placed
within the globe b, and the wires c, d, passed into the tube e; the two halves are
then fused together, and a vacuum produced by mercury. The wire c dips into the
mercury a short distance only, the mercury itself serving as a conductor, but the
wire d, which is insulated, passes through the mercury. The height of the column
of mercury, when not otherwise indicated, is shewn by dotted lines Z.
Having thus described the nature of my Invention, and shewn by Drawings
how the same is to be or may be performed, I would have it understood that I do
not confine myself to the precise details herein shewn, as it will be evident from the
examples given that the construction of apparatus may be varied according to
requirement, but what I claim as my Invention is,—
Firstly. The construction of electric lamps in such manner as to admit of the
production and maintenance of a vacuum by means of one or more columns of
mercury, substantially as herein shewn and described, whereby Sprengel's pumps
and air pumps air dispensed with.
Secondly. The various methods herein shewn and described of establishing the
electric current within the lamp without passing the conducting wires through the
glass, as has heretofore been done.
In witness whereof, I, the said Thomas Howard Blamires, have hereunto set
my hand and seal, this Thirtieth day of July, in the year of our Lord One
thousand eight hundred and eighty.
THOMAS HOWARD BLAMIRES. (L.S.)