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Патент USA US2112322

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March -29, 1938.
K. s. wYA’TT
2,112,322
CABLE
Filed Jan. 18, 1935
19 TEE/771757
Nif/7071279
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Patented Mar. 29, 1938
2,112,322
~ ` UNITED STATES PATENT OFFICE
2,112,322
CABLE
Kenneth S.'Wyatt, Detroit, Mich., assignor to
The Detroit Edison Company, Detroit, Mich.,
a corporation of New York
Application January 18, 1935, Serial No. 2,328
14 Claims.
This invention relates to the insulation of elec
l tric cables so‘that they are able to withstand
. Kthe tremendous electrical stresses created during
`
the use of the cable.
More speciñcally this invention relates to the
insulation of cables for electric current trans
mission having one or more centrally arranged
conductors enclosed in a lead sheath and having
(Cl. 173-264)
these products seems to be their ability to carry
current, which, of course, increases the dielectric
loss in the cable. Some of these products are un
doubtedly deterioration or oxidation products and
all of them impair the electrical characteristics 5
to some extent, particularly when they collect
in large quantities.
Although voids in cable insulation, occurring as
insulating material surrounding the conductors . a result of expansion followed by unequal con
10 rendered active for the adsorption of such harm
traction tend to facilitate the collection of large 10
ful products a`s maybe formed during the use masses of deterioration products, it is possible`
of the cable or which may be present therein under some circumstances that any ionized mole
when the cable is manufactured.
cules present could collect in the vapor state
Cables of the type above referred to are gen
within the insulation, to form a gas pocket.
15 erally formed by wrapping one or more electric
- current conductors with an insulating impreg
'natedmateriaL oils and various types of fibrous
9
materials such as paper tape being used for this
purpose. The'tape is wound around the conduc
tors to provide a pluralityof conductor insulat
» inglayers, and one or more conductors, which
may becoated with a metal shielding tape, are
surrounded with a packing material such as jute.
cellulose fiber, etc., the packed conductors then
25 being sheathed Within the customary lead cover
ing in the well known manner.
If desired an
additional insulating belting may be wrapped
around the jute or cellulose fiber packing and
the so wrapped mass covered with the lead
30 sheath.
In my copending application Serial No. 693,697,
ñled October 16,-1933, which has matured to
Patent 2,083,889 dated June 15, 1937 and en
titled “Oxidation resistant cable” I have de
35 scribed how the harmful effects of oxidation of
the insulating material can be prevented by the
incorporation of anti-oxidants into the inner and
outer windings of the insulation.
It now appears that other products may have
40 Aa deleterious effect on cable operation, some of
Other deterioration products, forming perhaps 15
around any catalyzer which may be present, also
collect in relatively large continuous bodies.
I propose to reduce the harmful effect of the
several deterioration products by locating Within
the insulating material agents adapted actively 20
to adsorb these products, and by preventing the
collection of large bodies of these lharmful prod
ucts, it is possible to minimize the amount of
current which they carry and thus reduce their
harmful effect on the insulating material.
25
These adsorbing agents, designed to adsorb the
various harmful or deterioration products pres
ent in the cable, may b_e used in'conjunction with
theanti-oxidant material disclosed in my above
referred to application, or they may be used by
themselves, depending upon the type of product,
which under various conditions, appears to be
most harmful.
_
The use of agents of this nature will permit
the use of a poorer grade of paper or oil under
certain circumstances, the cable insulation then
undergoing what may be called a refining action
in place.
_
It is therefore an object of this invention to
provide an electric cable with insulating material 40
these products perhaps being present in the cable 'which is protected against the inñuence of de
as originally manufactured, and some products terioration products present in the cable.
undoubtedly representing combinations of some
A further object of this invention is to make
of the original materials present, some of these
l 45 combinations probably being formed as a result
ofthe conditions .caused by operation of the
cable.
Among these harmful products may be listed
moisture, hydrogen, carbon dioxide, carbon
50 monoxide, sulphur compounds, nitrogenous com
pounds, hydro-carbon acids such as the substi
tuted acetylencs, dispersed cellulose particles
carrying electric charges, metal soaps, and ions
of these or other substances formed by the
55 several forces present. 'I'he harmful effect of
use of the adsorptive properties of certain ma
terials for reducing the harmful effect due to 45
ionization of the insulating materials used in
electric cables.
A further object of this invention is to reduce
the impairment of the insulating properties of
cable insulating materials by dispersing active 50
adsorbing agents throughout said materials.
Other and further objects of this invention will
be apparent from the following detail descrip~
tion of the accompanying sheet of drawings which
forms a part of this specification.
-
55
2
2,112,322
ing use of the cable, or that are present originally.
On the drawing:
Figure 1 is a sectional view of a three-con
ductor belted cable having paper insulation tape
wound around the conductors with adsorbing
agents dispersed between the layers of the wound
tape, and with anti-oxidant material impregnated
into the inner and outer windings of said tape.
Figure 2 is a vertical cross-sectional view of
a three-conductor H-type cable having oil im
pregnated paper tape surrounding each conductor
with adsorbing agents dispersed between the
windings of the tape, and with anti-oxidant ma
terial impregnated into the inner and outer wind
ings of said tape.
i
`
Figure 3 is a vertical cross-sectional view of
one of the insulated conductors shown in Figure
l having oil impregnated paper tape wound there
around with an adsorbing agent dispersed be
tween the inner and outer layers only of the in
sulation windings.
Figure 4 is a vertical cross-sectional view of one
of the conductors shown in Figure 1 having oil
impregnated insulation paper tape wound there
around with an adsorbing agent dispersed between
each of the layers of tape.
As shown on the drawing:
'
In Figure l, the reference numerals Il, I I, and
I2 indicate respectively the three sets of wires
forming the three cable conductors. Each con
ductor III, II, and I2 is surrounded with a cov
ering of mineral oil impregnated paper tape I4
wound therearound. The ürst few inner wind
ings IB of the paper tape I4 are treated with an
anti-oxidant material
such _ as hydroquinone,
camphor or the like, in accordance with the in
vention disclosed in my application Serial No.
693,697. 'I'he last few outer windings I6 are sim
ilarly treated with anti-oxidant material.
In accordance with this invention an active ad
40 sorbing agent such as activated charcoal, de
hydrated silicic acid (silica gel), dehydrated fer- -
ric hydroxide gel, exploded cellulose übers or sim~
ilar material I1 capable of adsorbing ions is dis
persed between the windings of the paper tape
I4. This adsorbing agent is readily applied, in
dry comminuted form, to the oil impregnated in
sulation tape by dusting the adsorbing agent over
the oil soaked tape. The oil ülm on the tape acts
as an adhesive and retains a sufiicient amount of
50 adsorbing agent thereon.
Alternatively the übrous insulating tape itself
may be made, in a dry atmosphere, of exploded
cellulose fibre or other similar material capable
of adsorbing ions and other deterioration prod
55 ucts. Instead of dusting the adsorbing agent over
the tape, the agent may be mechanically entan
gled in the über of the paper itself, this process
also being carried on in the absence of moisture,
the tape thereafter being immediately wound on
60 the conductor in order to minimize the adsorption
of moisture by the agents.
A üller material I8 such as jute or cellulose fiber
is packed around the outside of the paper tape I4
and the entire mass is wrapped in an insulation
05 belting I9. A lead sheath 20 forms the outside
of the cable and surrounds the insulation belting
I9.
.
The cable disclosed in Figure 1 is thus composed
of three conductors for electric current having
70 paper tape insulation to separate the conductors.
The insulation is impregnated in the inner and
outer windings with anti-oxidant material and an
y adsorbing agent is dispersed between the wind
ings of the tape to actively adsorb any ions or
other deterioration products that are formed dur
In Figure 2, the reference numerals 2i, 22, and
23 indicate respectively the wires forming the
three conductors of an H-type cable. Each con
ductor 2l, 22, and 23 is surrounded by an insula
tion covering comprising a plurality of layers of
oil impregnated insulation paper 24. The inner
windings 25 of the insulation paper are treated
with anti-oxidant material to minimize the harm
ful eü'ects of oxidation of the paper or of the
oil. Likewise the outer windings 2l are also im
pregnated with an anti-oxidant material. In ac-V
cordance with this invention materials capable
of adsorbing deterioration products, such as ions
etc., are dispersed between the windings of the
paper insulation 24 as shown at 21.
A copper shielding tape 2l is then wound around
the paper insulations in each conductor and the
three conductors are packed together in a lead
sheathing 29. Filler material such as cellulose 20
fibers 3|! are provided to üll up the spaces between
the insulated conductor and the outside lead
sheath.
The cable disclosed in Figure 2 is thus composed
of three conductors having windings of paper in 25
sulation separating the same from each other.
Anti-oxidant material is impregnated into the, in
ner and outer insulation windings of each con
ductor and an agent capable of adsorbing ions is
dispersed between the windings of each paper in 30
sulation. A shielding tape then surrounds the
windings of each conductor and the three conduc
tors are packed together in a lead sheath.
In Figure 3 the conductor 33 has wrapped there
around a plurality of windings of paper insulation ~
34. The ürst few inner windings li have dispersed
therebetween an ion adsorbing material or agent
31 such as is described above. Likewise the last
few windings 36 have the ion adsorbing material
31 dispersed therebetween. ’I'he insulation 24 40
thus has the adsorbing agent dispersed between
the inner and outer windings only, since the ioni
zation occurs more at these positions.
In Figure 4 the reference numeral 4B indicates
a conductor for electrical current having insula
tion paper 4I wrapped therearound. Adsorbing
material such as activated charcoal, hydrated
silicio acid or exploded cellulose übers 42 are dis
persed between the layers of the paper insulation
4I. These materials can be used alone or to
gether in any manner required by the type of im 50
purities present.
,
From the above description of the drawing it
is evident that cables can be prepared according to
this invention with insulation tape wound around
the conductors and having adsorbing agents irn- '
pregnated between some or all of the layers of
the tape. In addition speciüc anti-oxidant mate
rial can be incorporated or impregnated into the
inner and outer windings of the insulaton tape as
shown in Figures 1 and 2.
.
60
These adsorbing agents as a class have extended
surfaces capable of holding, by surface attraction,
the ions and other particles of deterioration prod
ucts. Substances having a high adsorptive ability
coupled with a low power factor such as activated 65
charcoal, dehydrated silicio acid and dehydrated _
ferrie hydroxide, are suitable adsorbing agents
for these materials. I also propose to use freshly
exploded paper. pulp, or _textile übers.
These
materials are exploded in much the same manner
as cereal grains are exploded to form the weli
known puffed cereals. In other words the textile
übers or pulp are-subjected to high steam pres
sure and then shot into the atmosphere where
they burst or expand and develop extended sur
3
2,112,322
faces. Other means, well known in the art for
separating the micelles may also be used. The
extended surfaces of these fibrous portions are
capable of adsorbing ions and the other deteriora
tion products mentioned above.
By dlspersing the adsorbing agents between the
layers of the insulation tape it is possible to ad
sorb the ions in the layers of adsorbing agents as
they are formed and prevent their accumulation
in any given spot as might otherwise occur, such
accumulation of the :fons Gauting breakdown of
the cable insulation.
When adsorbing agents are used with insulating
paper or oil material which is rich in harmful
15 products, the agents will, by removing them from
the ñber of the paper or from the oil, tend further
to reñne the insulating material so that such ma
terial can, in spite of impurities present in the
original cable, yet give adequate service in oper
20 ation.
Since the electrical stresses are greatest at the
conductor and again in the vicinity of the sheath,
ions in the liquid and solid phase occur in great
est numbers at these points and consequently it
25 is desirable in some circumstances to concentrate
ion adsorbing materials at these points. Ions in
the gas phase, however, are formed in that zone
of the cable insulation which, after operation,
contains the most voids. Since the location of the
30 voids varies with the type and manufacture of
the cable, although usually it occurs in the inner
third of the insulation, adsorbers for ions in the
vapor phase will be located in accordance with
the requirements of the individual cable.
y35
thereof.
5. In an insulated cable having a plurality of
conductors for electric‘ current, oil impregnated
insulation tape wound around said conductors, a
non-conductor ion adsorbing agent dispersed be
tween the layers of said insulation tape and a
covering for said cable.
6. A cable comprising a plurality of conductorsfor electrical current, oil impregnated paper
wound around each of said conductors, a non
conductor ion adsorbing agent dispersed between
the inner windings and between the outer wind
ings of said tape, and means for covering the so
insulated conductors.
7. A cable comprising a plurality of conductors
for electrical current, insulating material wound
around each of said conductors, activated char
coal dispersed between the layers of said insulat
ing material and a sheath for the so insulated
conductors.
8. A cable comprising a, plurality of conductors
for electrical current, insulation material wound
around each of said conductors, dehydrated silicic
acid dispersed between the layers of said insula 25
tion material and means for sheathing the so in
sulated conductors.
9. A cable comprising a plurality of conductors
for electric current, insulating material wound
around each of said conductors, exploded ñbrous 30
material dispersed between the layers of said in
sulation material and means for sheathing the
so insulated conductors.
I am aware that numerous details of the proc
10. A cable for transmitting electric current
comprising three conductors, oil impregnated pa
ess and apparatus may be varied through a wide
per tape wound around each of said conductors
range without departing from the principles of
this invention, and I, therefore, do not propose
limiting the patent granted hereon otherwise than
.40 necessitated by the prior art.
I claim as my invention:
1. A cable comprising conductors, insulation
wound around each conductor and a non-con
ductor ion adsorbing agent dispersed between the
45 windings of said insulation.
2. A cable comprising a conductor for electric
current, insulating means wound around said con
ductor and a non-conductor ion adsorbing agent
dispersed between the windings of said insulating
50
adsorbing agent dispersed between the windings
means.
t
3. An electrical cable comprising an electrical
conductor, layers of insulating material surround
ing said conductor, a non-conductor ion adsorb
ing agent dispersed between the layers of insu
lating material and an outside covering for said
cable.
4. In an insulated electrical cable, oil impreg
nated paper tape insulation wound around the
current conductors having a non-conductor ion
to form a plurality of layers therearound, a non
conductor ion adsorbing agent dispersed between
said layers, a filler surrounding the insulation
material and a lead sheathing enclosing the in
sulated conduits.
ll. A cable having a conductor for electric cur
rent and a non-conductor ion adsorbing insulat
ing means surrounding said conductor.
l2. A cable comprising a conductor, insulating 45
material surrounding the conductor, and non
conducting ion adsorbing insulation refining ma
terial dispersed between adjacent portions of said
insulating material, said refining material being
insoluble in said insulating material.
50
13. The process of refining the insulating ma
terial of a cable which includes the step of re
fining said material after the assembly of said
cable with a non-conducting ion adsorbing agent.
14. In an electrical cable having a plurality of 55
conductors,
oil impregnated insulation tape
wound around each of said conductors, and ac
tivated charcoal disposed between the layers of
said tape.
KENNETH S. WYA'I'I’.
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