Improved Method of Making Insulating Conduit Tubes.
Year: 1898

page_text: Date of Application, 24th Nov., 189Ɛ- Accepted, 21st Jan., 1899
COMPLETE SPECIFICATION.
Communicated from abroad by G. BRANDT, of 4, Kochstrasse, Berlin, S.W., in the
German Empire, Patent Agent.
Improved Method of Making Insulating Conduit Tubes.
I, CARL BOLLÉ, 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 ascertained in
and by the following statement:—
This invention relates to the manufacture of insulating conduit tubes consist-
ing of an impregnated tube of fibrous material covered with metal and consists in
a new or improved method by means of which I can produce a cheaper and lighter
metal covered conduit than by any other known method which conduit will yet
have sufficient mechanical strength for ordinary purposes.
In carrying out my invention I proceed as follows: I take two or more rolls
of long, commonly called, endless, strips of fibrous material, such as parchment,
oilpaper, oilcloth, paraffin paper, vulcanite fibre or paper impregnated with some
suitable hydrocarbon and also a roll of thin metal such as brass, copper or iron,
also of long length and suitable width, cut to an exactly uniform breadth through-
out its entire length. The insulating strips, after passing through liquid glue or
paste, are put into a drawing die and drawn over a shaping mandril to give them
a tubular form, butting their edges together parallel to the axis of the mandril;
the strips must be so arranged, that their butting seams will be set off one against
the other so that no two seams will come together. By a suitable drawing device
the insulating strips and the metal strip are drawn through the forming die at the
same time, a folding device being provided to make a clasping seam between the
two edges of the metal strip. On the drawings, Fig. 1 shows the manner of making
the tube, Figs. 2, 3 and 4 show sections of the tube in three stages of production.
C shows an insulating strip drawn over mandril D. B is another insulating
strip, drawn over C in such a way that the butting seams will not come above each
other. In passing through the drawing die, the fibrous strips will be united with the
metal covering strip A forming together a compact tube as the drawing die exerts
a considerable pressure on all the strips forming the tube.
As the tube emerges from the drawing die it is cut in to suitable lengths con-
venient for handling. It is evident, that such tubes may also be made of shorter
strips of material cut beforehand to a suitable length.
If the fibrous strips have been impregnated with a fusible insulator, such as
asphaltum, coaltar pitch or other hydrocarbon, heat may be applied to the finished
tube so as to thoroughly unite the different strips of fibrous and insulating material
with each other and the metal covering strip.
It is not novel to cover conduit tubes by metal strips such as brass or iron in
order to give them more mechanical strength, but the description herein before
given shows an entirely new or improved method of making an insulating conduit
and covering the same with metal, all in a single operation, while the practice
heretofore consisted in first making an insulating conduit tube and then by a
separate process protecting it with a metal sheathing.

page_text: 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 what I
claim is:
1. The method of making in one operation an insulating tube from strips of
insulating and fibrous material, such as parchment, oilpaper, paraffin paper
vulcanite fibre or paper, impregnated with suitable hydrocarbon, by drawing the
same through a drawing or folding die simultaneously with a strip of metal, the
edges of which are folded together while passing through the die, and by means
of a die clasped in each other, forming a solid tube of the strips substantially as
herein before described and illustrated by the drawings.
2. In the manufacture of conduit tubes, made as described in Claim 1, the appli-
cation of heat to the tubes, in order to melt the impregnating substance within,
and uniting thus all the component parts of the tube into one single body.
Dated this 22nd day of November 1898.