the Insulating Coverings of Electrical Apparatus.
Year: 1886

page_text: the Insulating Coverings of Electrical Apparatus.
I, NICOLAS JULES RAFFARD of 16 Rue Vivienne, Paris, France, Civil 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:-
This invention has for object Improvements in the method of and apparatus for
desiccating the insulating coverings of electrical apparatus.
When the invention is applied to the manufacture of metallic conductors insulated
and covered or not with a protecting coating of lead for underground or other
electric lines, it is carried out by means of an apparatus, the construction of which
is illustrated by Fig. 1.
This apparatus consists of a closed vessel A B of any form, communicating with
an air pump by the pipe C, and with a vacuum gauge D. This closed vessel is
surrounded with a steam jacket E F which permits of the temperature being raised
to the degree desired. Two orifices I and H provided with packings m and n
similar to Bramab's leathers, serve to guide the covered cable or conductor to be
desiccated, and form a joint preventing communication of the space A B with the
exterior, whilst the cable is passing through the apparatus following the direction
of the arrow.
As shown in Fig. 1, the cable or electric conductor coated with its coverings,
passes before entering the desiccating apparatus, through a vessel K containing
the substance with which it is to be coated, and on leaving the apparatus it passes
through a second vessel L containing paraffin or other suitable substance.
The invention can likewise be applied to (1) the desiccation of the coatings and
insulating coverings employed in the manufacture of the soft iron coils or cores of
electrical machines, whether they are composed of discs or are built up of iron
wire; (2) To the desiccation of solenoids coils or bobbins of magneto-electric or
dynamo-electric machines, whether generators or motors; (3) To the desiccation of
the elements of electro-magnetic induction machines, of secondary transformers, and,
of all apparatus of which the different parts are insulated by silk, canvas, card-
board, asbestos, caoutchouc, wood or other similar non-conducting substances,
whether covered or not with coatings of paint or varnish; (4) To the desiccation
Elaine C

page_text: of the bobbins of measuring instruments, voltmeters, ampere-meters, &c; (5) To
the desiccation of the elements of apparatus of high tension or generators of static
electricity, such as glass plates, condensers, Leyden jars, &c.
The desiccation of the bobbins of electro magnetic machines, of coils or armatures,
and even of dynamo electric machines erected complete, is effected by an apparatus
such as shown in Fig. 2, consisting of a vessel A hermetically closed, communicating
with an air pump or the condenser of a steam engine.
This vessel A is provided internally with a worm S in which circulates steam so
as to heat the apparatus to the degree desired, or it may be heated by direct fire.
In certain cases it might be of advantage to heat the conductors whilst they are
submitted to the action of the vacuum, by means of an electric current; for that
purpose the conductors are caused to pass through the walls of the apparatus
through plugs of insulating substance.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is -
1
1. Desiccation of the insulating coverings of electrical conductors, and of the
various elements of electrical instruments and machines as described above by
submitting them to the action of a vacuum in suitable apparatus capable of being
heated substantially as specified above.