Improvements in Condensers for Alternating Electric Currents.
Year: 1891

page_text: Date of Application, 29th Jan., 1891
Complete Specification Left. 29th Oct., 1891-Accepted. 19th Dec. 1891.
PROVISIONAL SPECIFICATION.
Improvements in Condensers for Alternating Electric Currents.
I, JAMES SWINBURNE, of Broom Hall Works, Teddington, Electrical Engineer,
do hereby declare the nature of this invention to be as follows
My invention has reference to the manufacture of electrical condensers for
alternate current distribution. According to my invention such condensers are
made by heating thin paper, preferably of the kind known in the trade as butter
skin, to a temperature of about 100 C. for some time. When thoroughly dried
by this means, the paper is soaked in a hydrocarbon such as paraffin oil. Sheets
of tinfoil are used as plates and the whole condenser is sealed up in an airtight
case. Instead of paraffin oil I may use melted ozokerite or a similar compound.
A vacuum may be used to avoid air bubbles.
Dated this 10th day of January 1801
COMPLETE SPECIFICATION.
Improvements in Condensers for Alternating Electric Currents.
I, JAMES SWINBURNE of Broom Hall Works, Teddington, Middlesex, Electrical
Engineer 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 improvements in condensers for use in electric
lighting and distribution of power..
In making condensers for high pressures such as 2000 volts difficulties arise from
heating of the dielectric, and from the insulation breaking down. Condensers
have been in use for many years for telegraphic and scientific purposes. In these
the dielectric is generally paper soaked in paraffin wax or mica. I find neither of
these dielectrics suitable for large condensers for high pressures.
The dielectric I employ is thin paper. I prefer the kind known as "butter
skin"; but many other kinds will do. The condenser is built up of thin layers of
paper and tin-foil, and is then compressed and baked in a suitable oven for several
days at a temperature of about 100 C. It is then immersed in paraffin oil. To
make sure that the oil finds its way into all the interstices I sometimes exhaust the
vessel containing the condenser before running the oil in.
The finished condenser is packed in a cast iron box the plates being still clamped
together under pressure. The leads are taken out through suitable blocks made of
celluloid, or other insulating material that is not soluble in paraffin oil.
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 I do not
claim high pressure condensers, or alternate current condensers generally; but that
what I claim is :
1. A high pressure condenser with a liquid dielectric, for use in electric lighting
& distribution of power.
2. A high pressure condenser with a dielectric consisting of paper or thin fibrous
material saturated with an insulating fluid, for use in electric lighting & distribution
of power.
3. An alternate current condenser with a liquid dielectric.

page_text: 4. An alternate current condenser with a dielectric consisting of paper or thin
fibrous material soaked with an insulating fluid.
5. A condenser substantially as described.
6. A. condenser in which the pile of plates is baked after making up and before
soaking.
7. A condenser which is soaked in an insulating material after being made up.
8. A condenser in which the fibrous part of the dielectric is baked before being
soaked in an insulating material.
Dated this 28th day of October 1891
JAS. SWINBURNE.