IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS
Year: 1882

page_text: LETTERS PATENT to John Jameson, of Akenside Hill, in the Town and
County of Newcastle-upon-Tyne, Consulting Engineer, for an invention of
IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS.
PROVISIONAL SPECIFICATION left by the said John Jameson at the Office
of the Commissioners of Patents on the 6th April 1882.
JOHN JAMESON, of Akenside Hill, in the Town and County of Newcastle-
upon-Tyne, Consulting Engineer. IMPROVEMENTS IN INCANDESCENT ELECTRIC
LAMPS,
I deposit the carbon from which the filaments for Incandescent Electric lamps
are to be formed within a tube of refractory material as regards endurance of heat
from hydro carbon gas or vapour subjecting it to such condition as regards heat
and pressure and the gas or vapour supplied as to produce a deposit of great
density and uniformity of structure.-When the deposit is formed of considerable
thickness I break off the envelope employed in its formation and then to give
endurance to the cylinder so formed, fill the inside with a tenacious cement such as
rosin or shellac and saw off a series of discs or grind them off with sand and water
and a hoop iron saw so as to reduce the deposit formed to a series of thin rings, or
I cement the end from which a disc or ring is to be cut to a plate so as to give the
disc increased endurance while it is being cut. I attach the rings on one side to a
plate of any convenient material as glass or metal by means of tenacious cement,
and grind the opposite side of the ring on the flat side of a revolving emery wheel
or by other convenient means so as to get a straight surface or if thickened ends of
the carbon filaments are desired I regulate the grinding by such arrangements as
to leave uniform ridges of extra thickness.-I then detach the ring and cement it
on its other side and grind again so as to reduce to the desired thickness.-I
then while it is still attached to the plate turn a series of concentric or similar
shaped rings in the carbon ring so as to give to each filament the requisite depth
and thereafter I divide the rings into, 2, 3, or more sections and then soften the
cement and remove the carbons from the plate on which they were shaped.-A
convenient cement for the attachment of the discs is melted shellac.-By these
means I am enabled to produce a carbon filament of great density and uniformity
of structure and to reduce it to approximately accurate dimensions with little risk
of fracture.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Jameson in the Great Seal Patent Office on the
3rd October 1882.
JOHN JAMESON of Akenside Hill in the City and County of Newcastle-
upon-Tyne, Consulting Engineer IMPROVEMENTS IN INCANDESCENT ELECTRIC
LAMPS.
•
I deposit the carbon from which the filament for Incandescent Electric Lamps
are to be formed within a tube of refractory material as regards endurance of heat
from hydro carbon gas or vapour subjecting it to such conditions as regards heat
and pressure and the gas or vapour supplied as to produce a deposit of great
density and uniformity of structure.-When the deposit is formed of considerable
thickness I break off the envelope employed in its formation, and then to give
endurance to the cylinder so formed fill the inside with a tenacious cement such as
rosin or shellac and saw off a series of discs or grind them off with sand and water
and a hoop iron saw so as to reduce the deposit formed to a series of thin rings or
I cement the end from which a disc or ring is to be cut to a plate so as to give the
disc increased endurance while it is being cut: I attach the rings on one side to a
plate of any convenient material as glass or metal by means of tenacious cement
and grind the opposite side of the ring on the flat side of a revolving emery wheel
or by other convenient means so as to get a straight surface or if thickened ends
of the carbon filaments are desired I regulate the grinding by such arrangements
as to leave uniform ridges of extra thickness. I then detach the ring and cement
it on its. other side and grind again so as to reduce to the desired thickness.--I
then while it is still attached to the plate turn a series of concentric or similar
shaped rings in the carbon ring so as to give to each filament the requisite
depth and then I afterwards divide the rings. into 2, 3, or more sections and
then soften the cement and remove the carbons from the plate on which they
were shaped.-A convenient cement for the attachment of the discs is melted
shellac.
By these means I am enable to produce a carbon filament of great density and
uniformity of structure and to reduce it to approximately accurate dimensions with
little risk of fracture.
I deposit the carbon from which the filaments for Incandescent Electric lamps
are to be formed within a tube or retort of refractory material as regards heat such
as porcelain from hydro carbon gas or vapour subjecting it to such conditions as
regards heat and pressure and the gas or vapour supplied as to produce a deposit of
great density and uniformity of structure. The conditions referred to being a very
high degree of heat, a small pressure, a not too rich gas or vapour and uniformity
of supply. When the deposit is formed of considerable thickness I break off the
envelope employed in its formation for facility in which operation I may so
construct the envelope in two or more parts as that it can be separated into its
parts and from the carbon deposit without actual fracture, or I may make in it
certain weaker parts than others so as to facilitate its fracture. The seperation of
the parts of the tube from the deposit is facilitated by forming the matrix of glazed
porcelain or other refractory fine clay, so as that the deposit formed is entirely
superficial and does not penetrate and adhere to the matrix as it would if there
were no glaze. To give endurance to the cylinder so formed of deposited carbon
during the process of its removal from its matrix and subsequently I fill the inside
with a tenaceous cement capable of setting hard such as rosin or shellac and while.
supported by this cement I saw or grind off a series of discs with sand and water
and a hoop iron saw or emery or an emery wheel or other convenient means so as
to reduce the deposit formed to a series of rings or I cement the end from which

page_text: the disc or ring is to be cut to a plate so as to give the disc increased endurance
while it is being cut and I cut close to this attached end.-I may however arrest
the process of deposit of carbon at a stage when only the desired thickness of
deposit for one filament has been formed, and as a matter of convenience I may
insert a spindle concentrically with the deposit and run in the cement between
them so as to facilitate manipulation in the process of seperation of the filaments.
-If however the deposit has been carried so far as to be greater than the
desired thickness of one carbon I attach the rings before described to a plate of
any convenient material as glass or metal by means of tenaceous cement and I
grind or turn while so supported to any desired shape and section giving such
support during this process by means of the cement as that the cutting may be
done with freedom and facility.-If the deposit be of such thickness as to furnish
2 or more filaments in the way of the thickness, I prefer to dress up on both sides
the rings to the desired accuracy of form before seperating the filaments from each
other in the other direction, and if during the process of manufacture I desire to
change the position of the carbon to be operated upon in reference to its cement, I
soften the cement, when it may be removed with facility I prefer to employ for
this
purpose an uniformily heated oven so as to exactly soften the cement to the
required degree and no more.-If thickened ends of the filaments be desired I so
regulate the grinding as either in case of deposit of minimum thickness to leave
widened ends or with a thicker deposit thickened or widened ends or both.-I may
also while using a tube or retort or other convenient form of vessel to serve as a
matrix for the deposit whether complete or in parts as described, use also within
it a trough or troughs of U shape for instance or other convenient form so as to
obtain additional surface for deposit and I operate this additional deposit by the
use of cement substantially as I have described, or I may when using the troughs
referred to neglect the deposit formed upon and within the tube itself and even
allow it to burn out by access of air between charges and use the deposit on the
enclosed matrix only.-A convenient cement for the attachment of the carbon
filaments is shellac in a melted state but other cements may be used.
By these means I am enabled to produce a carbon filament of great density and
uniformity of structure and to reduce it to approximately desired and accurate
dimensions with little risk of fracture.-Having thus described the nature of my
invention and the manner in which the same is to be performed I would have it
understood that I do not claim the mere deposit of carbon from hydrocarbon gas
or vapour by itself, but what I claim as my invention is this deposit combined with
the subsequent method of operating by means of a tenaceous cement so as to afford
freedom and facility of handling and reducing it to any desired dimensions
substantially as described.
In witness whereof I the said John Jameson have hereunto set my hand
and scal this Thirtieth day of September, One thousand eight hundred
and eighty two
Witness to the signature of John Jameson
JOHN BOWMER
Clerk
Gateshead-on-Tyne
J. JAMESON. (L.S.)