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Oct. 29, 1946. ~
_|, w_ bLsoN‘ ETAL
I . 2,410,127
- Filed Sept. 16, 1945 ~
V4C0 /14
H54DT0rR5U0M 250‘L"F.30
BYMM 63:2.0'411.
Patented Oct. 29, 1946 I
UNI TE fl;
John'W. Olson, Hastings-on-Hudson, N. Y., and
Charles W. Bechle, Sycamore, Ill.,1assignors to
Anaconda Wire and Cable Company, New York,
N. Y., a corporation of Delaware
"Application September 16, 1943, SerialNo. soacsz
4 Claims.
, >
( Cl. 91-13)
the-United States patent of Johnson and Olson
This invention relatesto insulated electric‘con
ductors, and has. forvits, object the provision "of
No. 2,228,766, there isdisclosed a combined and
simultaneous drying‘ and evacuating of the
?brous insulation with immediate impregnation
certain improvements ‘in vsaturating or impreg
nating the ?brousinsulation of such conductors
with a bituminous or‘asphaltic saturant.
Certain types of electric conductorsjand cables
by the ‘saturant. In passing the dried and evac
uated covered wire-immediately and directly into
the hot saturant; atmospheric pressure is permit
ted to force the saturant to 'a considerable height
in an upright evacuated chamber, thus, in effect,
waterproo?ng bituminous or asphaltic saturant.
At normal room temperatures, the saturant ‘is 10 sealing the end of the chamber communicating
with the bath of hot saturant. Such simultane
usually a solid or very viscous material, and it
ous drying and evacuating requires careful regu
is hence the usual practice to heat the saturant
lation and control to satisfactorily attain the two
to a temperature at which it is a mobile liquid,
.usuallyabout 350-‘375° F. When the fibrous in
. objectives.
sulation is immersed in this hot molten saturant, 15 In the course of ‘an exhaustive investigatiomwe
have found that the ‘?brous insulation vis very
excessive moisture in the ?brous‘ material is
are insulated with ?brous material, such as pa~
per, cotton and the ‘like, impregnated with a
completely-and satisfactorily impregnated with
.promptly volatilized, frequently with explosive
the saturantfwhen the insulation is ?rst dried
to a substantially negligible moisture content,
moisture, and when such ?brous insulation is im 20 then immediately subjected to a high vacuum,
‘and run directly into the saturant- while in ‘its
' mersedjin the hot saturant a substantial propor
vdried and evacuated conditio'n,fthe drying and
tion, if not all, of this moisture is volatilized with
Violence. Under normal atmospheric conditions,
the ?brous insulation usually contains 4—5% of
vacuum treatment "being ‘separate operations.
attendant objectionable ebullition ‘and foaming
Based on this discovery, the invention contemi
of the bath of hot saturant. . The ?brous insu-v
lation is ‘frequently a hard, tough, dense mate
25 plates the improvement in impregnating ?brous
insulation surrounding an electric conductor with
a s'aturant comprising drying and-evacuating the
?brous insulation in separate but succeeding op
erations, and then immersing the dried and eV'ac-'
rant. In other cases the ?brous insulation'is a
comparatively soft porous paper, such ‘as towel 30 uated insulation in :thefsaturant in its dried and
evacuated condition. In a preferred embodiment
ing stock, crumpled and twisted about the con
of the ,invention‘in ‘which the covered conductor
ductor and characterized by a multiplicity of
is drawn through a bath of the saturant in a
minute interstitial spaces which, are di?icultly
substantially continuous manner, the invention
?lled with the saturant solely by capillary action.
involves wrapping a‘ plurality of vconvolutions of
Bulk-drying of the ?brous insulation prior to '
the ‘covered conductor ‘over the heated cylindri
impregnation has heretofore been commercially
cal surface" of a'rota'table drum, and drawing the
practiced. In accordance with the customary
rial such as kraft paper, ‘and even when sub
stantially dry such material is di?icultly and
often incompletely impregnated with the satu
covered, conductorv directly - from the‘ drum
practice, the conductor covered with the ?brous
through ‘an-elongated vacuum chamber commu
insulation is wound on reels and dried ‘for about
16 hours in a dry kiln at a temperature of about 40 nicating vdirectly with the'bath of sa'turant. The
invention further contemplates a novel combina
200-250" F. The covered wire is usually tightly
tion of "apparatus *for carrying out the foregoing
wound on the reel to a radial thickness of about
vone foot. The inner turns onthe reel are seldom
improvements in impregnating ?brous insulation
satisfactorily dried, and frequently contain-up to
r 3% of moisture.
- with a saturant.
Moreover, due to the physical Y 45
discomfort in entering the dry kiln, theworkmen
usually take out two or more reels at a time, and
The foregoing and other novel ‘features of the
invention ‘Will'be betterunderst'ood'from the fol
lowing description taken in ‘conjunction with the
often appreciable moisture isre-absorbed by, the‘
accompanying drawing, in which
?brous material while the reel is exposed to the
atmosphere awaiting to be run through the so Fig. llis' an elevation, partlyyinrsection, of "a
combination of ‘apparatus ‘embodying the inven
tion, and particularly adapted for practicing the
Vacuum oven drying has also been proposed
aforementioned improvements in impregnating
for-drying the ?brous insulation prior to impreg
nation with the hot saturant, but this has proved
little,- if any, better than‘simplekiln drying. In
?brous insulation‘w'ith'asaturant, and
Fig. 2i_'is an enlarged sectional elevation of the
end of the vacuum chamber, in the apparatus of
Fig. 1, communicating with the saturant.
at the entrance or forward end of the vacuum
chamber, and is secured in position by a threaded
The drawing illustrates the impregnation of a
layer of ?brous insulation 5 surrounding and cov
ering an electric conductor ?feitherlstranded or
nut £9. The traveling covered conductor ?ts
tightly in the die 18 and effectively seals this end
of the vacuum chamber.
solid, with a hot molten saturant ‘i. The covered
The exit or rear end of the vacuum chamber
conductor is drawn (in the direction of the ar~
rows) from an unwinding reel or the like (not
shown) through the bath of saturant onto a
- has an inner shoulder 20 and a prolong 2! to
which is coupled an extension 22 extending be
10 low the surface of the bath of saturant.
winding-up reel or the like (not shown) in a sub
diameter of the prolong and extension may be
somewhat less than the diameter of the vacuum
chambenbut still su?icient to freely accommo
stantially continuous manner. Within the bath
of saturant, several convolutions of the covered
conductor are drawn over the surface of a rotat
date the largest covered conductor to be passed
ably mounted drum 8. The drum 8 may, if de
therethrough. The extension is coupled and se
cured to the prolong by a threaded nut 23.
A removable steel die 24 abuts against the
sired, be appropriately driven by any suitable
source of power, or it may rotate freely and all
the power required to draw the covered wire
shoulder 20 and is ?rmly held in position by
through the apparatus may be applied to the
aforementioned winding-up reel. The rate of
the traveling covered conductor which ?ts loose
ly in. this die. A water jacket, or chamber 25
surrounds the die 24, and serves to arti?cially
travel of the conductor and the number of con
volutions wound around the drum 3 are corre
lated to provide a su?iciently long immersion pe
cool the die. Any other suitable means for arti
?cially cooling the die 24 and the exit end of the
vacuum chamber may be provided.v An opening
riod to completely and satisfactorily impregnate
the ?brous insulation.
A removable steel die [8 is mounted
With a hot molten sat
urant of bituminous or asphaltic nature main 25 or manhole 26 and a cover 21 therefor are pro
vided in the vacuum chamber near the exit end
tained at a temperature of about 350-375” lit, im
for permitting access to the chamber when chang
mersion times of from 6 to 20 minutes are com
ing the die 24. The evacuating device is sup?
mon. It is to be understood, however, that the
ported by a bracket 28 secured to the side of the
invention is not limited to saturants of this na
9 and a post 29 near the forward end of
ture, but is applicable to any kind of saturant for
the device. The dies [8 and 24 may be of diifer
the ?brous insulation of electric conductors and
cables. The saturant ‘I is contained in a tank 5.
A wiper l0 secured to one side of the tank re
moves excess saturant from the covered conduc
tor as it is drawn from the tank.
In accordance with the embodiment of the
invention illustrated in the drawing, several con
volutions of the covered conductor are drawn over
ent sizes 'to' accommodate different sizes of cov
ered conductor.
As previously stated, the GOV?‘
ered conductor makes a tight ?t in the die l8
and a loose fit in the die 24.
In 'practicingthe invention the covered con
ductor is drawn over the heated drum l2 until
the moisture content of the ?brous insulation is
reduced to substantially zero. With the cylin;
drical peripheral surface of the drum heated’to
a rotatable drum ‘I2. The drum .is mounted to
a temperature of 250-300"
the covered con
rotate freely about its horizontal axis, and is
ductor should remain in contact with the heated
rotated by the drawing of the covered conductor
surfaceior from‘ 3 to 8 minutes,-'depending upon
thereover. The rate of travel of the conductor,
the size of the covered conductor, in order to
the heated cylindrical peripheral surface ll of
the number of convolutions wound around the
drum l2 and the temperature orthe cylindrical
surface H of the drum are correlated to heat
the ?brous insulation until its moisture content
is substantially negligible. It will be understood
that the drum l2 (and likewise the drum 8) is ‘
provided witha “pusher” device of conventional
construction for properly aligning the ?rst and
last convolutions of covered conductor on the
drum with the supply reel, (not shown) and the
evacuating device, respectively.
The drum [2 is shOWn in the drawing as heat
ed by- an interior steam chamber I3 adjacent
the cylindrical peripheral surface H. Steam is
supplied to the chamber l3 through a radial pipe
I4 connected to an axial steam supply pipe l5.
The cylindrical surface of the drum is advanta
geously heated to a temperature of 250-30050.
Any other suitable means of heating the cylin
drical surface of the drum l2 may be provided,
as for example, electric heating, gas ?ames, etc. 65
The evacuating device comprises an elongated
vacuum chamber it connected by a pipe I‘! to an
air pump or other suitable means (not shown)
reduce the moisture content of the ?brous insula
tion to substantially, zero. From the drum l2,
the dried insulated conductor passes directly and
immediately, and before any, moisture can be
reabsorbed by the ?brous insulation, through’ the
sealing die l8 into the vacuum chamber It.’ In
its travel throughv the vacuum chamber, air and
other‘gases’ are almost completely removed from
the interstitial spaces of the'?brous insulation.
The evacuated. covered ‘conductor is drawn
through the exit die 24 or the 'vacuurn, chamber
and'immediately contacts the. saturant which is
drawn up the extension 22 into the p1'olong'2i
as a resultof the vacuum and the comparatively
loose ?t between the covered conductor and the
diev 24. ' However, thesaturant will not pass ‘be
yond the die 24 into the vacuum chamben'bel
cause of vthe cooling effect of the water jacket 25.
The arti?cialf cooling at the exitj' endof the
vacuum chamber chills the. saturant in the‘ ad;
jacent part of the prolong, 2! to a very viscous
and almost solid condition, and this chilled'satu-i
rant cooperates withv the die 24 andjthetrave'ling
covered conductorto .e?ectivel‘y, sealithe exi't'end
of the vacuum chamber. Atthe same time‘, the
the chamber, say approximating" 30 inches of 70 travel of the covered conductor through the die
mercury. In practice, the vacuum chamber it
24 keeps. the die clear, and carries back into-the
may be from 3 to 5 feet in length, or even longer
hot saturant in the prolongj or’extensionjany
for maintaining as high a vacuum as possible in
if necessary.’ It is preferably cylindrical with a
accumulation .of chilled, saturant that, might
sectional diameter several times the diameter of . otherwise tend togclog the die; .The exit end, of
the largest covered conductor to be passed there 75 the vacuum tube is thus sealed'by‘the die 24, and
the traveling covered conductor in conjunction
with the chilled saturant surrounding the covered
surrounding an electric conductor as the covered ,
conductor is drawn through the bath of staturant
in a substantially continuous manner, of means
conductor as it enters the prolong 2|.
The invention provides a simple 'and effective
for heating the ?brous insulation in the course
method of and apparatus for saturating or im
of its travel towards the bath of saturant until
its moisture content is substantially negligible,
pregnating the ?brous insulation of electric con
ductors and cables. The entire operation of dry
and a vacuum chamber through which the dried
ing, evacuating and impregnating is carried out
covered conductor passes in its travel from said
in a substantially continuous and rapid manner.
heating means to the bath of saturant.
As contrasted with bulk-drying, the over-all time 10
2. The combination of claim 1, in which the
interval of operation is reduced by many hours,
heating means is the heated cylindrical periph
no large quantity of covered conductor is tied-up
eral surface of a rotatable drum over which the
in process, and no reabsorption of moisture, after
covered conductor is drawn.’
drying, can take place. The separation of the
3. The combination of claim 1, in which the
drying and evacuating treatment enables each 15 heating means is a rotatable drum having an
to be carried out under optimum conditions.
interior steam chamber adjacent its cylindrical
Evacuation following drying is particularly ad,
peripheral surface for heating that surface to a
vantageous, since the vacuum is called on to
temperature suf?ciently high to remove substan
remove only air or other occluded gases from
tially all of the moisture from the ?brous insu
the interstitial spaces of the already substantially 20 lation as a plurality of convolutions of the cov
dry insulation. This is of special advantage in
ered conductor are drawn over the drum.
impregnating crumpled and twisted paper insu
4. The combination with means for holding a
lation which inherently is honey-combed with
hot saturant bath for impregnating ?brous insu
minute interstitial spaces which, even when the
lation surrounding an electric conductor, of a
insulation is bulk-dried in accordance with previ 25 rotatable drum whose cylindrical peripheral sur
ous practice, cannot be completely ?lled with
face is adapted to be heated to a temperature
saturant by capillary action, the only force or
su?iciently high to remove substantially all of the
means available to draw the saturant into the
interstitial spaces.
lation is evacuated
tion, the saturant
pressure into the
moisture from the ?brous insulation as a plu
When the dry, ?brous insu
rality of convolutions of the covered conductor
in accordance with the inven 30 wrapped around the drum are drawn over the
is forced under atmospheric
drum, and an elongated vacuum chamber having
evacuated interstitial spaces,
a sealing die at each end through which the
thereby promptly and completely ?lling these
dried covered wire is adapted to be drawn directly
spaces with saturant. When the conductor has
from said drum, the exciting end of the vacuum
a layer of rubber or the like interposed between
chamber being in direct communication with the
it and the ?brous insulation, the invention insures
hot saturant bath and the die at that end of
complete impregnation of the ?brous insulation
the chamber being arti?cially cooled to prevent
without impairing the underlying layer of rubber.
seepage of the saturant into the vacuum chamber.
We claim:
1. The combination with means for holding a 40
saturant bath for impregnating ?brous insulation
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