Improvements in and relating to Conduits for Electrical • Conductors.
Year: 1896

page_text: Date of Application, 11th May, 1896
Complete Specification Left, 11th Feb., 1897-Accepted, 1st May, 1897
PRO
SJONAL SP
TION.
Improvements in and relating to Conduits for Electrical
• Conductors.
1, FREDERICK BATHURST of No. 14 Green Croft Gardens, South Hampstead,
in the County of Middlesex Electrical Engineer do hereby declare the nature of
this invention to be as follows :-
My invention relates to certain improvements in and relating to conduits for
electrical conductors and has for its object the armouring or sheathing of an
insulating tube by surrounding it with a complete metallic tube or casing.
In carrying my invention into effect I employ primarily a tube or conduit of any
suitable insulating substance or material, preferably one which retains its solidity
under comparatively high temperatures. A strip of zinc, or any suitable alloy, is
bent to present a U section and the tube aforesaid is laid within it, and two or
more roller dies are caused to press upon the outer strip, and while continuously
feeding it forward, also closes it upon the central tube, the edges being close
together but not at this period united. The continuous length then is caused to
pass through a die, or set of dies arranged as brushes or the like, and charged with
spent acid, or what is generally known as "pickle." This effectually cleans the
surface of the metal, and the whole is then caused to pass through a bath of melted
solder which closes the opposed edges and completes the tubular armouring. I may,
as a finishing process cause the continuous length to pass through a set of burnishing
dies, or planishing rolls.
Ju order to perfect a system of conduits for electrical conductors, according to
my invention, 1 construct bends, T and elbow connections by covering the inner
insulating tube, suitably formed or shaped, with an armouring or sheathing
corresponding to that of the continuous length hereinbefore described.
Deter this cab do. of M 1900
FREDK. WALKER,
73 St. Stephen's Road, Upton Park, London, E.,
Agent for the Applicant,
COMPLETE SPECIFICATION.
Improvements in and relating to Conduits for Electrical
Conductors.
I FREDERICK BATHURST, of No. 14 Greencroft Gardens, South Hampstead
in the County of 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 relates to certain improvements in and connected with conduits for
electrical conductors, and has for its object the armouring or sheathing of an
insulating tube by surrounding it with a complete metallic tube or casing.

page_text: In order to render the description of my said invention clearly, I have appended
the accompanying sheet of drawings to which reference may be had.
Figure 1 shows the insulating tube when first placed within the armouring, and
Figure 2 is a view of the same when the armouring is completed.
Figure 3 is a longitudinal section showing one method of jointing said armoured
conduit, and Figure 4 is a similar view showing a modification thereof, and
Figure 5 is a perspective view of the ferrule or jointing socket.
In carrying my invention into effect, I employ primarily a tube or conduit of any
suitable insulating substance or material, preferably one which retains its solidity
under comparatively high temperatures. Said tube or conduit is indicated by B
throughout the views, and other reference letters are similarly repeated to indicate
the same parts throughout. A strip A, preferably of zinc, but which may be of
any metal or alloy, is bent as shown by Figure 1 to present a U section, and the
tube B laid within it, and two or more roller dies, or other suitable tools are caused
to press upon the outer strip A, and while continuously feeding in a longitudinal
direction, closes said strip A upon the tube B as shown by Figure 2, the two
edges of the strip A, viz., a a' being pressed close together. The continuous length
of armoured conduit thus formed is caused to pass through a die or set of dies
arranged as brushes or the like and charged with spent acid, or what is generally
known as "pickle." This effectually cleans the surface of the metal, and the whole
is then passed through a bath of melted solder which seals the edges a a¹. I may
as a finishing process cause the coutinuous length to pass through a set of burnishing
dies or planishing rolls to effect a perfectly uniform and polished surface.
The mechanism or apparatus used in the first part of the process, viz., that in
which the strip A is closed over the tube B may be of any known kind or type
generally used for such purposes, and similarly the second part of the process,
consisting in cleaning and to some extent fluxing the armoured conduit ready for
the third part, in which a continuous soldering process is effected, may be carried
out simultaneously by any set of, or combination of rolls, dies, baths, or the like,
which are well known in the art of tube making, and do not form a part of my
invention, and therefore do not require a detailed description.
In jointing the lengths of conduits made according to my invention I employ &
sleeve or ferrule C, Figures 3, 4 and 5, which may consist in a strip A' forming the
armouring of the joint and corresponding to the armouring A of the conduit to
be jointed, with a central bush D of insulating material corresponding to the
insulating tube B and abutting upon each portion thereof in the continuous
lengths.
Referring to Figure 3 the armouring A on the two lengths of conduit to be
joined, is stripped at b b so that the single sleeve A may be placed over the
insulating tube B, thus bared, the bush D completing the insulation. The several
joints are shown in the drawings somewhat open, for the purpose of aiding the
description of the invention, but in practice are absolutely closed. The sleeve C
may be merely fitted upon the projections 6 61 of the insulating tube B after
stripping off the armouring A. In Figures 4 and 5 a composite sleeve C is shown,
which consists in two armourings c and d concentrically arranged one over the
other. In this case the joint is not "flush" or even as that shown by Figure 3,
but overlaps the armouring A of the tubes to be jointed, the insulating bush D
intervening and preserving the insulation of the bore intact as shown. The two
armourings c and d afford increased elasticity, so that the mere frictional grip is
sufficient without soldering or brazing. The single armoured coupling shown by
Figure 3 may similarly be overlapped to secure the structural strength afforded by
the armouring A of the conduits.
I prefer to use zinc as an armouring, for the reason that it is a well known fact
that zinc becomes ductile at a temperature of from 200° Fab. to 220° Fah. which is
within the range of using boiling water as a heating medium. Thus, in carrying
out the wiring of a building or other installation, the armoured conduit may be

page_text: made to conform to curves and angularities in the structure, without impairing the
hermeticity or insulating properties thereof.
I may, according to my invention construct bends, elbows, or angular joints or
connections in the form of sleeves or ferrules with an interior bush of insulating
material to meet in jointing and correspond to the insulating tube B in the lengths
of armoured conduit.
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 ;-
First. In the construction of conduits for electrical conductors, the combination
of a zinc, or zinc alloy armouring, pressed around and enclosing a tube of insu-
lating material, for perfectly sealing and insulating the interior bore, substantially
as and for the purposes herein described with reference to the appended drawings.
Second. In the construction of conduits for electrical conductors the method of,
and means for securing a concentric armouring by the processes of closing a strip
of zinc or like metal around a tube of insulating material, cleaning the same,
and soldering the joint thereof by a continuous action, substantially as herein
described.
Third. In conduits for electrical conductors the method of and means for jointing
lengths thereof, by a sleeve or ferrule A¹ Figure 3, carrying an interior bush D,
substantially as herein described with especial reference to Figure 3 of the
accompanying drawings.
Fourth. In conduits for electrical conductors the method of and means for
jointing lengths thereof by using a sleeve or ferrule C, composed of two concentric
sheathings & and e in combination with an interior bush D substantially as and for
the purpose herein described and shown by Figures 4 and 5 of the appended
drawings.
Fifth. In conduits for electrical conductors the combination of a zinc, or zine
alloy armouring with an interior insulating tube substantially as and for the purposes
herein described with reference to the appended drawings.
Dated this 28th day of January 1897.
FREDK. WALKER,
73, St. Stephen's Road, Upton Park, London, E.,
Agent for the Applicant.