Improvements in Electrical Insulation Conduits, and in the Method of and Apparatus for making same.
Year: 1898

page_text: Date of Application, 18th Jan., 1898-Accepted, 19th Feb., 1898
COMPLETE SPECIFICATION.
Improvements in Electrical Insulation Conduits, and in the Method
of and Apparatus for making same.
(A communication from abroad by the LITHOSITE MANUFACTURING COMPANY, a
Corporation under the laws of the State of Missouri, of Saint Louis, in said
State, in the United States of America.)
°
I, PHILIP MIDDLETON JUSTICE, of 55 and 56 Chancery Lane, London, in the
County of Middlesex, Chartered Patent Agent, 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: -
Figure 1 is a view illustrating the improved method of, and apparatus for
making electrical insulation conduits;
Figure 2 is a detail view of a portion of the head and tail stocks of a lathe,
with the mandrel upon which the conduit is formed in position;
Figure 3 is a longitudinal sectional view through the improved conduit; and
Figure 4 is an enlarged cross-sectional view of the same.
This invention relates to a new and useful improvement in methods of, and
apparatus for, making electrical insulation conduits, the object being to make a
conduit which will be light, strong, and an effective insulator.
The invention consists, generally stated, in a method, hereinafter described, of
making electrical conduits, which consists in winding a fibrous materal, preferably
treated with a cementitious substance, on a suitable mandrel by which said conduit
is given its shape, then hanging, or suspending, said mandrel by one end, so that
the conduit will slip off by its own gravity which polishes the interior thereof,
giving the said interior a certain grain, or fibre, and preserving its shape, so that,
when said conduit has passed from its mandrel, it will harden in the shape desired.
Another feature of the invention resides in the apparatus for carrying this
method into effect, which consists in the combination of a supply of fibrous
material, a trough containing a cementitious substance in which said fibrous
material is immersed, means for removing the surplusage of cementitious material,
and a mandrel upon which said fibrous material so treated is wound, said mandrel
having at one end a centering device and a hook, or eye, by which the mandrel is
suspended after the conduit is wound thereon.
Other features of invention reside in the construction, arrangement; and com-
bination of the several parts, all as will hereinafter be described, and, afterwards,
pointed out in the claims.
In the drawings, A indicates the floor and B the ceiling of a room, C the joists
under the ceiling, said joists C being preferably provided with suitable pegs, nails,
or other supporting devices, c, from which the mandrels are suspended when con-
duits are hung up to dry, and which, by their own gravity, slip from said mandrels.
D indicates a reel, preferably supported from the joists C, which reel carries a
supply of fibrous material E, which is preferably in the form of burlap, or other
fibrous material may be used if desired.

page_text: F indicates a trough or box arranged on the floor A, and carrying a roller G
under which the. fibrous material E passes, and, in so doing, is immersed in a
cementitious substance of a character to be hereinafter described. After becoming
saturated with the cementitious material in box F, the fibrous material E passes
between two rollers H and H¹ which remove the surplus cementitious material, as
is well understood.
I indicates a suitable table, or support, upon whose ends are arranged a head
stock J and a tail stock K. Head stock J has attached to it a crank j by which
said head stock may be turned.
it
L indicates a mandrel, on one end of which is arranged an eye- or hook, 7, said
eye or hook being formed with a centering device to co-operate with the tail
stock K. The other end of mandrel L carries a suitable locking plate by which
engages the revoluble head stock J, locking the mandrel to said head stock so
that said mandrel may be rotated. The fibrous material, after being saturated
with the cementitious substance in trough F, passes between rollers H and H¹
and is wound on mandrel L, said mandrel being given as many turns as it is
desired to apply thicknesses of the fibrous material. When a sufficient number of
thicknesses have been wound on the mandrel, the fibrous material E is severed,
and the mandrel again turned and painted with the cementitious substance in
box F. The ends of the fibrous material are now trimmed by a suitable knife, the
mandrel being turned at the same time.
After the fibrous material has been wound on the mandrel, a straight tube X
is formed, as shown by dotted lines in Figure 2. The fibrous material being wound
on the mandrel, the mandrel is removed from between the stocks J and K, and a
short section of a tube Y is slipped over one end of the tube X, as shown in Figure 3.
This section Y is of the same material, but is firm and hard, having been previously
made and hardened and cut in short sections for placing on the ends of the green
tubes X. The mandrel is now hung up by its eye or hook on the pins c, and
gravity, asserting itself, causes the green conduit to slip down off the mandrel,
centering device M being placed immediately thereunder to receive the green
conduit, and to support it in a vertical position after it leaves the mandrel. The
hardened collar Y forms a hard base for the green conduit and prevents the same
from becoming bent over or marred in this action. The centering devices M are
preferably arranged on a base plate m, so that they may be removed when a conduit
is received thereon and other centering devices substituted in their place, to
receive other green conduits which may be suspended from the hooks or pins c.
The conduits are left on the centering devices M until they are sufficiently hard to
be handled without danger of crushing them, or destroying their contour. When
the conduits are slipping from the mandrels, the fibrous material is given a grain,
and, at the same time the interior of the conduit is polished so as to make it smooth
and even.
In addition to the collar Y acting as a firm support for the green conduit, it, also,
acts, as a joining collar when the conduits are laid in position, end to end, making
a tight joint with the end of the adjacent conduit introduced thereinto. In laying
the conduits end to end, it is preferred to use cementitious material on the end of
the conduit introduced into the collar Y, so as to make a tight joint between
the two.
The composition of the cementitious material in box F, to be used in connection
with making the conduit, consists of the following ingredients:
There is taken of liquid chloride of magnesium a suitable quantity which is of
the consistency of thirty degrees Beaume. After ascertaining the percentage of
calcium chloride therein, there is added an equal amount of oxalic acid to
neutralize the said calcium chloride. This is to prevent sweating in the conduit
by the slacking of the lime. To every pint of chloride of magnesium, is then
added one and one-half pounds of oxide of magnesium, and, in order to quicken
the process of drying, there is added a quantity of sal-ammoniac with the oxide of
magnesium equal to about five per cent thereof.

page_text: The filler used in connection with this cementitious mass may be any of the
following ingredients introduced in proportions of about one to one, that is, fifty
percent of filler and fifty percent of the mass composed of magnesium chloride and
oxide of magnesium as before described: Graphite, powdered talc, slate dust,
pyrites, powdered mica, or other suitable material. It is preferred in the selection
of this filler, to use one which is, of itself, a non-conductor of electricity.
This mass is thoroughly mixed in the box F, and the fibrous material immersed
therein, and saturated therewith, as before described.
After the fibrous material has been wound on the mandrel and given the shape
desired, and before the mandrel is hung up, as before described, the green conduit
may if desired be immersed in a bath of chloride of zinc to close the pores thereof.
This immersion can, also, take place after the conduit has become hardened.
It is recognised that the proportion of the ingredients, and the ingredients
themselves, in the improved cementitious substance, may be changed, and that the
construction and arrangement of the apparatus for carrying the improved method
into practice, may be modified to suit different conditions, without, in the least,
departing from the nature and principle of the invention.
Having now particularly described and ascertained the nature of said invention,
and in what manner the same is to be performed, as communicated to me by my
foreign correspondents, I declare that what I claim is:-
1. The herein described method of making insulation conduits, the same con-
sisting in treating a fibrous material with a cementitious substance, winding the
fibrous material so treated on a mandrel, and then removing the mandrel, substan-
tially as described.
2. The method herein described of making insulation conduits, the same consisting
in treating a fibrous material by immersing the same in a cementitious substance,
winding said fibrous material so treated on a mandrel, and then hanging said
mandrel up by one end, permitting the fibrous material to slip off by reason of its
own gravity, substantially as described.
3. The method herein described of making insulation conduits, the same con-
sisting in immersing a fibrous material in a bath composed of chloride of
magnesium, oxide of magnesium, and a suitable filler, then winding said fibrous
material so treated on a mandrel, and removing said mandrel, substantially as
described.
4. The herein described method of making insulation conduits, the same con-
sisting in immersing a fibrous material in a bath composed of chloride of
magnesium, oxide of magnesium, and sal-ammoniac, mixed with a suitable filler,
winding said fibrous material so treated on a mandrel, or frame, to give it shape,
and immersing the fibrous material after being so treated, in a bath of chloride
of zinc to close the pores thereof, and then removing said conduit from the mandrel,
substantially as described.
The herein described method of making insulation conduits, the same con-
sisting in immersing a fibrous material in a bath composed of chloride of
magnesium, oxide of magnesium, and a filler, such as graphite, powdered talc,
slate dust, powdered mica, pyrites, or other suitable material, winding said fibrous
material so saturated on a suitable mandrel to give it shape, and then removing
said mandrel, substantially as described.
6. The herein described method of making electrical conduits, the same con-
sisting in winding a fibrous material treated with a cementitious substance on a
suitable mandrel, placing a hardened collar on one end of said green conduit, then
suspending said mandrel so that the green conduit will slip off of the same by
gravity, the hardened collar on the end of the green conduit acting as a base or
support, and preventing the end of the green conduit from becoming upset or
marred, substantially as described.
7. The herein described apparatus for making insulation conduits, the same
comprising suitable stocks, and a mandrel having a hook or eye formed on one

page_text: end with a centering device beyond said hook or eye, and a locking device at the
other end of said mandrel, substantially as described.
8. The combination with a mandrel, of a conduit pipe which is formed thereon,
and a centering device arranged immediately below said mandrel and adapted to
co-operate with said conduit pipe to center the same as it leaves the mandrel
substantially as described.
9. As a new article of manufacture, the herein described conduit pipe com-
prising a number of layers of fibrous material bound together by a cementitious
substance, substantially as described.
10. As a new article of manufacture, the herein described conduit pipe com-
prising a winding of fibrous material bound together by a cementitious substance,
and a collar cemented on one end of said pipe for projecting therebeyond, said
collar comprising a winding of fibrous material bound together by a cementitious
substance, substantially as described.
101
Tanam 1900