Improved Electrical Insulating Conduit.
Year: 1892

page_text: Date of Application, 7th June, 1892
Complete Specification Left, 4th Mar., 1893-Accepted, 8th Apr., 1893
PROVISIONAL SPECIFICATION.
[Communicated from abroad by CHARLES W. JIFFERSON, of Schenectady, in
the County of Schenectady and State of New York, Electrician.]
Improved Electrical Insulating Conduit.
1 CARL BOLLÉ of 57 Barton Arcade, Manchester in the County of Lancaster,
Consulting Engineer do hereby declare the nature of this invention to be as
follows:-
My invention relates to a tube or cylinder made of mica scales as distinguished
from comminuted mica. The tube can be made of any size or length.
The object of my invention is to provide a tube to be used for the purpose of
electrically insulating and mechanically protecting any substance, or liquid employed
as an electrical conductor.
The tube is made in the following manner, sheet mica constituting the bulk of
the material composing the tube: The natural mica is split up into laminæ
extremely thin, say from one to two mils. in thickness, which I call elementary
mica scales. These are pasted with a suitable liquid gum upon a piece of sheet
iron previously dusted with soap stone, so as to form continuous sheets or strips of
any desired size or thickness, and with the edges of the individual pieces of mica
overlapping so as to give the sheet some strength.
For a short tube or cylinder, this mica sheet of the same width as the required
length of tube is rolled upon a rod or mandril until the required thickness of mica
is obtained. If each layer of mica sheet is pasted as wound on, and the parts
allowed to set before the mica is slipped off the rod, a very solid tube composed
almost entirely of mica is obtained, so solid that it can be turned or bored in a
lathe in the same manner as wood, iron etc. The object of the soap-stone is to
facilitate the removal of the built up sheet from the iron surface.
To obtain a longer tube, mica strips are wound spirally, with their edges over-
lapping, around a tube or rod, several layers being wound on the top of each other
with their joints overlapping at different parts of the tube, until the required
thickness is obtained.
To facilitate the bending of the built up mica sheets or strips round the rod upon
which the tube is formed, a gum that will soften with heat is used to fasten the
small elementary scales and sheets of mica together, such as "white French
varnish."
When using mica sheets or strips that are in a very flexible or almost wet
condition, a pipe that has steam and cold water connections is used for forming the
mica tube upon. The method is as follows: Form the mica tube in the manner
hereinbefore described when the pipe is cold. When formed and secured, turn on
the steam and cook the tube until the paste has become dry. Then turn off the
steam and turn on the cold water which will set the gum. When the tube is hard,
take it off the pipe.
In building up the mica either in sheets or strips, it adds to the ease in handling
the mica sheet or strip when in a plastic condition, to paste upon one side, (or both
sides if preferred) a sheet of some tissue paper having a long fibre, or some thin
textile fabric. A sheet that has just been made is baked upon a heated plate
until it has obtained some degree of toughness caused by the solvent of the gum
evaporating.
To cut large sheets into strips, the sheet has to be fairly dry, and to form tubes
with dry strips, they must be softened with heat before they are wound upon the
rod, which must also be a pipe with steam connection.
D: 21 Jav. of Tuna 1800

page_text: COMPLETE SPECIFICATION.
Improved Electrical Insulating Conduit.
I, CARL BOLLE of 57 Barton Arcade, Manchester in the County of Lancaster,
Consulting 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 relates to electrical insulating conduits or tubes and consists in the
formation or manufacture of a tube or cylinder made of mica scales as distingushed
from comminuted mica. The tube can be made of any size or length.
The object of the invention is to provide a tube to be used for purpose of
electrically insulating, and mechanically protecting any substance or liquid
employed as an electrical conductor.
Sheet mica constitutes the bulk of the material.
The natural mica in all cases is split up into laminæ extremely thin; say from 1
to 2 mils., which I call elementary non-comminuted mica scales. These are pasted
with a suitable liquid gum upon a piece of sheet iron, previously dusted with soap-
stone, so as to form continuous sheets or strips of any size or thickness, and with
the edges of the individual pieces of mica overlapping, so as to give the sheet some
strength.
For a short tube or cylinder this mica sheet, of the same width as the required
length of tube, is rolled up on a rod or mandril until the required thickness of mica
is obtained. If each layer of mica sheets is pasted as wound on, and the paste
allowed to set before the mica tube is slipped off the rod, a very small solid tube
composed almost entirely of mica is obtained, so solid that it can be turned in a
lathe in the same manner as wood iron &c.
The object of the soap stone is to facilitate the removal of the built up sheet
from the iron surface.
To obtain a longer tube, mica strips as before mentioned are wound spirally,
(with their edges overlapping) around a tube or rod, several layers being so wound
on the top of each other with their joints overlapping at different parts of the tube,
until the required size is obtained.
To facilitate the bending of the built up mica sheets or strips round the rod
upon which the tube is formed, a gum that will soften with heat is used to fasten
the small sheets of mica together, such as "white French varnish"
or shellac.
When using mica sheets or strips that are in a very flexible or almost wet or
green condition, a pipe that has steam and cold water connections is used upon
which the mica tube is formed. The method is as follows:-Form the mica tube
when the pipe is cold. When formed, and secured, turn on the steam and cook the
tube until the paste has become dry. Then turn off the steam, and turn on the
cold water which will set the gum. When the tube is hard, take it off the pipe and
prepare to make another.
In building up the mica cither in sheets or strips, it adds to the ease in handling
the mica sheet or strip when in a plastic condition, to paste upon one side (or both
sides for that matter) a sheet of some tissue paper that has a long fibre, or some
textile fabric. A sheet that has just been made is baked upon a heated plate
until it has obtained some degree of toughness, caused by the solvent of the gum
evaporating.
To cut large sheets into strips, the sheet has to be fairly dry, and to form tubes
with dry strips they must be softened with heat before they are wound upon the
rod, and the rod or mandril must also be a pipe with steam connections.

page_text: Having now particularly described and ascertained the nature of my inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is.
1. The manufacture, and use of electrical insulating conduits consisting of con-
volutions of elementary mica scales with their edges overlapping, and varnish or
similar insulating cement between said convolutions and between the mica scales,
substantially as hereinbefore described.
2. The manufacture and use of electrical insulating conduits consisting of
convolutions of cloth covered mica scales and an insulating cement holding the
same together in a mass, substantially as hereinbefore described.
3. The manufacture and use of electrical insulating conduits consisting of strips
composed of joined mica scales, and wound helically upon one another in layers
with their edges overlapping one another, substantially as hereinbefore described.
4. The manufacture and use of electrical insulating conduits consisting of the
combination of layers of helically wound strips of mica scales and cement holding
the same together, substantially as hereinbefore described.
Dated this 3rd day of March 1893.
CARL BOLLE.