Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1323328
TlllS AppllCat1011 i9 a dlvlslollal of applicatlon No.
~1~7,19' filed on Julle 22, 1~8~, llOW Canadlarl ~atent 1,253,455.
FIELD OF THE INVENTION
This inventlon relates to contact rollers useful ln a
process and an apparatus for the contlnuous production of metal
coated filaments.
D~SCRIPTION OF THE PRIOR ART
Filaments comprising non-metals and serni-metals, such as
carbon, boron, sllicon carbide, polyester, nylon, aramid, cotton,
rayon, and the like, in the form of monofilaments, yarns, tows,
mats, cloths and chopped strands are known to be useful in re-
inforcing metals and organic polymeric materials. Articles com-
prising metals or plastics reinforced with such fibers find wide-
spread use in replacing heavier components made up of lower
strength conventional materlals such as aluminum, steel, titanium,
vinyl polymers, nylons, polyester, etc., in aircraft, automobiles,
office equipment, sportlng goods, and in many other fields.
A common problem in the use of such filaments, and also
glass, asbestos and others, is a seemlng lack of abllity to trans-
late the properties of the hlgh strength fllaments to the materlalto whlch ultlmate and intimate contact ls to be made. In essence,
even though a high strength filament ls employed, the fllaments
are merely mechanically entrapped, and the resulting composite
pulls apart or breaks at disappointingly low applled forces.
The problems have been overcome in part by depositing a
layer or layers of metals on the indlvldual filaments prior to
q~
.
- 2 ~ 1323328
61109-7296D
incorporating them into the bonding material, e.g., metal or
plastic. Metal deposition has been accomplished by vacuum
deposition, e.g., the nickel on fibers as described in United
States patent No. 4,132,828; and by electroless deposition from
chemical baths, e.g., nickel on graphite filaments as described
in United States patent No. 3,894,677; and by electrodeposition,
e.g., the nickel electroplating on carbon fibers as described in
Sara, United States patent No. 3,622,283 and in Sara, United
States patent No. 3,807,996. When the metal coated filaments of
such procedures are twisted or sharply bent, a very substantial
quantity of the metal flakes off or falls off as a powder. When
such metal coated filaments are used to reinforce either metals
or polymers, the ability to resist compressive stress and tensile
stress is much less than what would be expected from the rule of
mixtures, and this is strongly suggestive that failure to
efficiently reinforce is due to poor bonding between the filament
and the metal coating.
It has now been discovered that if electroplating is
selected and if an amount of voltage is selected and used in
excess of that which is required to merely dissociate (reduce)
the electrodepositable metal ion on the filament surface, a
superior bond between filament and metal layer is produced. The
strength is such that when the metal coated filament is sharply
bent, the coating may fracture, but it will not peel away. More-
over, continuous lengths of such metal coated filaments can be
knotted and twisted without substantial loss of the metal to
flakes or powder. High voltage is believed important to provide
or facilitate uniform nucleation o~ the electrodepositable metal
- 3 - 1323328
61109-7296D
on the filament, and to overcome any screening or inhibiting
effect of materials absorbed on the filament surface.
Although a quantity of electricity is required to
electrodeposit metal on the filament surface, an increase in
voltage to increase the amperes may cause the filaments to burn,
which would interrupt a continuous process. The aforesaid Sara
patent No. 3,807,966, uses a continuous process to nickel plate
graphite yarn, but employs a platiny current of only 2.5 amperes,
and long residence times, e.g., 14 minutes, and therefore low,
and conventional voltages. In another continuous process,
described in United Kingdom patent No. 1,272,777, the individual
fibers in a bundle of fibers are electroplated without burning
them up by passing the bundle through a jet of electrolyte carry-
ing the plating material, the bundle being maintained at a
negative potential relative to the electrolyte, in the case of
silver on graphite, the potential between the anode and the fibers
being a conventional 3 volts.
The invention of the parent application provides an
efficient apparatus to facilitate increasing the potential
between anode and the continuous filament cathode, since it is a
key aspect of the present process to increase the voltage to
obtain superior metal coated filaments. In addition, since it
permits extra electrical energy to be introduced into the system
without burning up the filaments, residence time is shortened,
and production rates are vastly increased over those provided by
the prior art. As will be clear from the detailed description
which follows, novel means are used to provide high voltage
plating, strategic cooling, efficient electrolyte-filament contact
- 4 - 1323328
61109-7296D
and high speed filament transport in various combinations, all of
which result in enhancing the production rate and quality of metal
coated filaments. Such filaments find substantial utility, for
example, when incorporated into thermoplastic and thermoset
molding compounds for aircraft lightning protection, EMI/RFI
shielding and other applications requiring electrical/thermal
conductivity. They are also useful in high surface electrodes
for electrolytic cells. Composites in which such filaments are
aligned in a substantially parallel manner dispersed in a matrix
of metal, e.g., nickel coated graphite in a lead or zinc matrix
are characterized by light weight and superior resistance to
compressive and tensile stress. The apparatus of this invention
can also be employed to enhance the production rate and product
quality when electroplating normally non-conductive continuous
filaments, e.g., polyaramids or cotton, etc., if first an
adherent electrically conductive inner layer is deposited, e.g.,
by chemical means, on the non-conductive filament.
SUM~ RY OF THE INVENTION
The present invention seeks to provide filaments formed
of a conductive semi-metallic core with metallic coatings.
The present invention also seeks to provide a process
in which the electroplating of the filaments is effected under
high voltage electroplating conditions.
The present invention further seeks to provide a
process and apparatus which will efficiently and rapidly coat
filaments with metallic coatings and facilitate the cleaning and
collecting of the finished product.
- 5 - 1323328
61109-7296D
In accordance with the invention of the parent applica-
tion, apparatus has been provided in which a plurality of
filaments can be simultaneously plated efficiently with a metal
surface and thereafter cleaned and reeled for use in a variety
of end products.
According to the invention of the parent application,
there is provided an apparatus for imposing tension on a
continuous fiber being passed through a continuous processing
operation comprising: means to pass the fiber at a determinable
fixed speed through the continuous processing operation, said
means being located upstream of said continuous processing
operation; an array of tension rollers, around which the fiber
passes in a mode reversing the direction of the path of the fiber,
said array of tension rollers being located downstream of said
continuous processing operation; and means to drive the array of
tension rollers in the same direction as the fiber at variable
speeds equal to or less than the speed of the fiber.
The apparatus is a continuous line provided generally
with a pay-out assembly adapted to deliver a multiplicity of
filamen.s to an electrolytic plating bath. The line includes a
pre-treatment process, after which the metal-plating is performed
in a continuous process by the passage of the clean fibers
through an electrolyte under high voltage conditions. Means are
provided to cool the filaments during the passage from the contact
roll associated with the electrolytic tank and the electrolyte
bath.
Further, the filaments pass over contact rollers into
the electrolyte. The line includes an assembly of tensioning
1323328
6 ~1109-7296D
rollers that serve to lnsure a tlght dlrect llne of the fllaments
from the contact roller to the electrolyte.
The lnven~lon of thls dlvlslonal appllcatlon comprlses a
contact roller comprlslng: (a) a removably mounted copper tube;
(b) a flrst flxed bearlng; (c) a bushlng mounted on the flrst
fixed bearing havlng an outslde diameter equal to the inside dia-
meter of the copper tube; (d) a second flxed bearlng mounted ln
allgnment wlth the flrst fixed bearlng; (e) a bushlng mounted on
the second fixed bearing, said bushlng havlng the same outside
diameter as the bushing mounted on the flrst flxed bearing; and
(f) means for translatlng the bushlng mounted on the flrst flxed
bearlng horlzontally to release the copper tube.
The tenslonlng rollers are comprlsed of a plurality of
driven rollers over which the filaments pass, and the path of the
filament is reversed to create tension. The tensioning rollers
are driven independently of the drive for the processing apparatus
and at a speed equal to or less than the speed of the filaments.
The speed is determlned by visual inspection.
The contact rollers are located in close proxi~lty to
the surface of the electrolyte, and by virtue of the processing
conditions require frequent change. As a result the contact
rollers are mounted on fixed aligned mounts. The mounts both
carry support bushlngs having an outside diameter equal to the
inside diameter of the contact roller.
DESCRIPTION OF THE DRAWINGS
The invention will be more readily understood when
viewed in association with the following drawings wherein:
Flgure 1 is a schematic view of the overa~l process of
. .;
- 7 ~ 1323328
61109-7296D
the subject continuous electrolytic plating process except for
the pay-out assembly.
Figure 2 is an elevational view of the pay-out section
arranged specifically to simultaneously deliver a multiplicity
of fibers to the electrolytic plating operation.
Figure 3 is a plan view of the pay-out assembly of
Figure 2.
Figure 4 is an isometric view of the wetting and
tensioning rollers between the pay-out and electrolytic bath.
Figure 5 is an elevational view of one electrolytic
tank.
Figure 6 is a plan view of the tank of Figure 5.
Figure 7 is a sectional elevational view through line
7-7 of Figure 5.
Figure 8 is an isometric view of the commutation
fingers.
Figure 9 is an isometric view of one contact roller in
association with the means for providing coolant to the fibers
and a current carrying medium from the contact roller to the
bath.
132~328
-- 8 -- .
FIGURE 10 is an elevational view of a section of
the electrolytic tank depicting an anode basket.
FIGURE 11 is a schematic of the electrolytic
coolant conductor and a contact roller.
FIGURE 12 is a sectional elevational view of a
contact roller of the process assembly.
FIGURE 13 is a detail of the end cap of the roller
of FIGURE 12.
FIGURE 14 is a partial detail of the opposite
end of the roller of FIGURE 12.
FIGU~E 15 is a view of the electrical system of
the present invention.
FIGURE :L6 is a drawing of the mechanism for
synchronously driving the apparatus of the subject
invention.
FIGURE 17 is a plan view through line 28-28 of
the section of FIGU~E 16.
FIGURE 18 is a side elevational view of the roller
assembly in the drying section of the system.
13 2 3 3 2 8 61109-7296D
The process and apparatus are directed to providing an
efficient and complete means for metal-plating non-metallic and
semi-metallic fibers.
The process relies on the use of very high voltage and
current to effect satisactory plating. As a result of the high
voltage and current, an apparatus has been developed that can
produce high volumes of plated material under high voltage
conditions.
The process and the apparatus particularly suitable for
practicing the process are described in the preferred embodiment
in which the specified fiber to be plated is a carbon or graphite
fiber and the plating metal is nickel. However, the process and
apparatus are suitable for virtually the entire spectrum of
metal-plating of non-metallic and semi-metallic fibers.
The overall process and schematic of the apparatus
except for the pay-out assembly are generally shown in Figure 1.
The operative process includes in essence, a pay-out assembly
for dispensing multiple fibers in parallel, tensioning rollers 6,
a pre-treatment section 8, a plating facility 10, a rinsing
station 12, a drying section 14 and take-up reels 16.
More particularly, the pre-treatment section 8 shown
generally in Figure 1 includes a tri-sodium phosphate cleaning
section 26 and an associated washing-tee 28, rinse section 30
and associated washing-tees 32 and 32A, a hydrochloric acid
section 34 and associated tee 36, and rinse section 38 with
associated washing-tees 40 and 40A. The plating facility 10 is
comprised of a plurality of series arranged electrolyte tanks
-- 10 --
61109-7296D
13~28
shown illustratively in Figure 1 as tanks 18, 20, 22 and 24,
each of which is charged with current by a separate rectifier,
better seen in Figures 5 and 15. The rinsing section 12, sho~m
generally in Figure 1, is comprised of tank and tee assemblies
similar to the pre-treatment apparatus. An arrangement of
cascading tanks 42 and tees 44, 44A and 44B cycle rinse solution
of water and electrolyte over the fibers 2. Thereafter, clean
water is passed over the fibers 2 in the rinse section 46
provided with tanks and washing-tees 48 and 48A. The rinsed
fiber 2 is then passed through section 50 wherein it is first
air blasted in chamber 53 and then steam treated in section 55
to produce an oxide surface on the metal plate. The process is
completed by passage of the metal plated fiber 2 through the
drying unit 14 and reeling of the finished fibers on take-up
reels 17 in the reeling section 16.
As seen generally in Figure 1, the apparatus is
provided with means to convey the fibers 2 through the
132~328
] ] (:)'J ~ J
system rapidly wlthout abradlng the flbers 2. The comblnatlon of
strateglcally loc~ated gulde rollers 51, tenslon rollers 6, force
iMposlng rollers ln the drylng section 14 and a synchronous drive
assembly shown in FIGURE 16 rapidly conveys -the fibers 2 through
the apparatus without abrasion of the fibers 2.
The operatlon begins wlth the pay-out assernbly 4 shown
ln FIGURES 2 and 3. Functlonally, the flbers 2 from the pay-out
assembly 4 are dellvered over a gulde roller 5 through the ten-
slonlng rollers Ç to the pretreatment sectlon 8 shown in Figure 1.
As best seen in FIGURES 2 and 3, the pay-out assembly 4
ls comprlsed of a frame 52 on whlch the pay-out rollers 54 are
mounted. The pay-out rollers 54 are mounted on the frame 52 on a
rall 56 and a rail 58. The rollers 54 on rail 56 are arranged to
pay-out the flbers 2 to the electroplatlng system whlle the rail
58 is an auxlliary rall adapted to mount the spare rollers 54
available to provlde alternate duty. A rail 60 mounts guide
rollers 62 over whlch the fibers 2 from the pay-out rollers 54
travel to reach the tensionlng rollers 6.
- ].2 ~ 1 32 3 328
61109-7296D
As best seen in Figure 2, the fibers 2 extend from the respective
rol].ers 54 over individual guide roller 62 associated with a
particular roller 54 to the common guide roller 5 and into the
tensioning roller assembly 6. Guide bars 59 are provided to
guide fibers 2 from the pay-out rollers 54 to the associated
guide rollers 62.
As seen in Figure 3, the guide rollers 62 are aligned
adjacent to each other to avoid interference between the fibers 2
as a plurality of fibers 2 are simultaneously delivered to the
system to be treated and plated.
The pay-out assembly 4 delivers the fibers 2 over a
guide roller 5 to a wetting roller 80 and then to the tensioning
rollers 6. A wetting tub 84 is provided with water which wets
the fibers 2 and enables suitable and more efficient cleaning
and rinsing of the fibers 2 during pre-treatment. The tensioning
rollers 6 seen in Figure 1 are shown in more detail in Figure 4.
The tensioning rollers 6 comprise an assembly of five
rollers 90, all of which are driven through a single continuous
chain 87 by a common source such as a variable speed motor 92.
Each roller 90 is mounted on a shaft 89 which also mounts a
fixed gear 91 around which the chain 87 is arranged. Idler
rollers 97 are also arranged to engage the chain 87. A gear 93
extending from
1~23328
13 61109-7296D
the shaft of the variable speed motor 92 drlves the contlnuous
chaln 87 through a chaln 101 and a gear 103 of Flgure 5 flxed to
the shaft 8g of a roller 90. It ls necessary that tenslon be
provlded to the fibers 2 at a locatlon in the llne upstream of the
flrst platlng contact roller. The platlng contact roller and the
flbers 2 must be ln tlght contact to facllitate the operation at
the high voltage and high current levels necessary for the pro-
cess. With tlght contact, low reslstance is provided between the
flbers 2 and the contact rollers, thus the hlgh current passing
through the system clrcult wlll not overload the flbers 2 causlng
destructlon of the flbers. As a result, the tenslon roller assem-
bly 6 is located upstream of the electroplatlng tanks 18, 20, 22,
24 ~FIGURE 1) to provlde that tenslon. On the other hand, the
fibers should be sub~ected to as llttle drag as posslble. ~nher-
ent ln the fibers 2 ls the tendency to separate at the surface and
accumulate fuzz. The varlable drlve motor 92 ls coupled to all
five of the rollers 90 to provide variable speed for the rollers
at some speed equal to or less than the speed of the fibers 2. At
carefully controlled speeds the necessary tenslon ls provided
wlthout causing fuzz to accumulate on the fibers. The apparatus
and process are designed to afford a tenslon roller assembly 6 ln
~ -~
~t
1323328
14 611(~ J
wllicll the tellsion rollers 90 travel at a slower speed than the
~ibers 2. The -tension on the flbers 2 ls maintained by varylny
the speed of the tension roller 90 in response to visual determi-
nation of the tension.
The pre-treated fibers 2 are next electroplated. As
seen in Flgure 1, a plurality of electroplating tanks 18, 20, 22
and 24 are provided in series. Under the high voltage-high cur-
rent conditions of the process, the series arrangement of electro-
platlng tank 18, 20, 22 and 24 afford means for providing discrete
voltage and current to the fibers 2 as a function of the accumula-
tlon of metal-plating on the flbers 2. Thus, depending on the
amount of metal-plating on the fibers 2, the plating voltage and
current can be set to levels most sultable for the particular
resistance developed by the flber and metal.
The electrolytic plating tank 18 of Figure 1 ls shown in
Figures 5, 6 and 7 and is identical ln structure to the plating
tanks 20, 22 and 24 shown ln Figure 1. The tank 18 is arranged to
hold a bath of electrolyte. The tank 18 has mounted therewith
contact rollers 100 and anode support bars 102 which are arranged
in the circuit. The contact rollers 100 receive current from the
bus bar 104 and the anode support bars 102 are connected directly
to a bus bar 106. Each of the plating tanks 18, 20, 22 and 24
13233~8
61109-7296D
are provided with slmllar but separate independent clrcuitry as
seen ln FIGURE 15. The anode support bars 102 have mounted there-
on anode baskets 110 arranged to hold and transfer current to
nlckel or other ~etal-platlng chlps.
Each tank 18, 20, 22 and 24 ls also provided with heat
exchangers 114 to heat the electrolyte bath to reach the desirable
inltlal temperature at start-up and to cool the electrolyte durlng
the high lntenslty current operatlon.
The tank 18 ls provlded wlth a well 103 deflned by a
solld wall 105 ln whlch a level control 107 ls mounted and with a
reclrculatlon llne 109. The reclrculatlon llne 109 lncludes a
pump 111 and 2 fllter 113 and functlons to contlnuously reclrcu-
late electrolyte from the well 103 to the tank 18. Under normal
operatlng condltions reclrculated electrolyte wlll enter the tank
18 and cause the electrolyte in the tank to rlse to a level above
the wall 105 and flow into the well 103. When electrolyte has
evaporated from the tank the level ln the well wlll drop and call
for make-up from the downstream rlnse sectlon 12 of Flgure 1.
The tank 18 ls also provlded wlth a llne 132 and pump
134 through whlch electrolyte ls pumped to a manlfold 128 that de-
llvers the electrolyte to the spray nozzle 130 a~ove the contact
rollers 100.
1323~28
lt` t,l 1()" /~
As ShOWIl in more detall in FIGURE lO, the ~ibers 2 pass
over the contAt rollers 100 arld al-oulld idler rollers 112 located
in proximity to the bottom of the tank. The idler roller~ 112 are
provided in pairs around which the Elbers 2 pass to rnove lnto con-
tact with the succeeding contact roller 100.
The rollers 100 in the tank 18 best shown in Flgure 15
communlcate wlth the bus bar 104 through contact member 118. The
detail of the contact member 118 seen in FIGURE 8 shows that the
contact members 118 are formed of a bar 120 and a plural array of
~ingers 122 and 124 that together provide the positlve contact
over a sufficiently large area on the contact roller lO0 to avold
creating a high resistance condition at the polnt of contact. The
fingers 122 and 124 are resiliently mounted on the bar 120 and by
the nature of the material, are urged lnto contact with the con-
tact roller 100 at all times.
Thus, a high strength positive electrical contact assem-
bly is provided ~or an environment wherein conventional brush con-
tacts cannot serve well.
The hlgh voltage-high current process of the present in-
vention is furtner facilitated by means for protecting the fibers2 durlng the passage between the electrolyte bath and the various
contact rollers. The system includes the recirculating spray
system 126 shown generally in FIGURES 5 and 6 through which
1323328
17 61109-72~6D
electrolyte ls recycled from the platlng tanks and sprayed through
the spray nozzles 130 on the flbers 2 at contact polnts on the
contact rollers 100.
The spray nozzles 130 are arranged with two parallel
tu~ular arms 136 and 138 best shown in Flgure 9 havlng nozzle
openlngs located on the lower surfaces thereof.
One tubular arm 136 of the spray nozzle 130, is arranged
to dlrect electrolyte tangentlally on the flbers 2 at the polnt at
whlch the fibers 2 leave the contact roller 100. The other tubu-
lar arm 138 of the spray nozzle 130 ls arranged to dellver elec-
trolyte directly on the top of the contact roller 100 at the polnt
at whlch the flber 2 engages the contact roller 100. As prevlous-
ly indlcated, lt ls vltal that sufflclent tenslon be applled on
the flbers 2 to insure that the flbers 2 are malntalned ln a tlght
direct llne between the contact rollers 100 and the ldler rollers
112. The need for a tight llne is to assure that the low contact
resistance suitable for current travel is avallable wlth hlgh
conductlvity through the flbers 2 from the contact rollers 100 to
the electrolyte bath. The electrolyte which ls reclrculated over
the contact rollers 100 and the flbers 2 provlde a parallel re-
slstor ln the clrcult and serve to cool the flbers 2.
It ls known that the rlbers 2 belng plated have
- 18 - 1323328
61109-7296D
a low fusing current, such as 10 amps for a 12K tow of about 7
microns in diameter. However, the process requires about 25 amps
between contacts or about 125 amps per strand in each tank.
Furthermore, both contact resistance and anisotropic
resistance must be overcome. The contact resistance of 12K tow
of about 7 microns on pure clean copper is about 2 ohms, thus
at 45 volts twenty-two and one-half amps are required before any
plating can occur. The anisotropic resistance is 1,000 times
the long axis. Thus, the total contact area must be 1,000 times
the tow diameter, which for 7 microns is 0.34 inches. Practice
has taught that one-half inch of contact will properly serve the
electrical requirement of the system when plating 7 micron tow,
hence two inch contact rollers 100 are used. It is also vital
that the contact rollers 100 be located at a specified distance
above the electrolyte bath to enable the system to operate at
the high voltages necessary to achieve the plating of the
process. In practice, it has been found that the contact rollers
100 should be located two inches from the electrolyte bath when
voltages of 16 to 25 volts are applied. Further, it has been
found that recirculation of about 2 gal~ons per minute per
contact roller traveling at about 1~ to 25 ft./min. will
properly cool the fiber
1323328
- 1 9
o
and~provide a suitable parallel resistor when above 5,000
amps are passed through the system.
The electrolyte in the process is a solution
constituted of eight to ten ounces of metal, preferably
in the form of ~iC12 and NiSO4 per gallon of solution.
The pH of the solution is set at 4 to 4.5 and the
temperature maintained between 145 and 150 F. Recir-
culation of the electrolyte through the spray nozzles 130
at the desired rate requires that the nozzle openings
be 3/32 inches in diame~er on 1/8" centers over the length of
each tubular arm 136 and 138. The presence of e~ectrolyte
on the fibers is vital, but care is taken to avoid
excessive electrolyte otherwise the contact rollers will
20 become su~jected to the plating occurring in the
electrolyte.
The contact r~lIers 1~0 are shown in detail in
FIGURES 12-14. Each contact roller 100 is located in
close proximity to the electrolyte in the plating tanks
and each is adapted to transmit high current through the
system in a high intensity voltage environment. The
30 contact roller 100 thus is designed for continual replace-
ment. The contact roller 100 is provided with fixed end
1323328
)~ f,ll(J'-~ /"~Jr,~,
mounting sections 170 and 172 which hold a cylindrical copper tl~be
17g. The cyl~lldr1cal copper tube 174 ls arranged to contact the
comMutator fingers 122-124 best shown in Figure 8 and deliver cur-
rent through both the flbers 2 and recycled electrolyte to the
electrolyte bath. The copper tube 174 is formed of conventional
type L copper which must be able to carry 350 amperes. The dia-
meter of the tubing is critical in that the diameter dictates the
contact surface for the fibers 2 and the distance that the contact
roller 100 will be from the electrolyte surface. As a result, the
mounts 170 and 172 are fi~edly arranged in alignment with each
other to releasably support the tube 174 of the contact roller
100. The mount 170 is provlded with a bearing support 176 through
which a screw mount 178 passes. The screw mount 178 rotatably
supports the copper tube 174 on a bushing support 180 and has the
capacity to release the copper tube 174 upon retractlon of the
bushing support 180 by withdrawing the screw 178. The mount 172
lncludes a bushing support 182 on whlch a detent 184 is formed.
Each copper tube 174 is provided with a notched mating slot 186 to
.it around the detent 184 and effect positive attachment of the
copper tube 174 to the bush1ng support 182 thereby obviating any
uncertalnty in alignment and facilitating dispatch ln replacing
each copper tube section 174.
~,
1323328
~l t,llO'~
The overall electrical system 188 of the process an~
apparatus ls shown schematically in Flgure 15 whereln t~,e capacity
for discrete appllcation of voltage and current to each electro-
lytlc tank 18, 20, 22, 24 can be seen. Conventlonal rectiflers
189, 191, 193 and 195 are arranged as a D.C. power source to de-
llver current to the respective contact rollers 100 on each
electrolytic tank. Bus bars 104, 194, 196, 198 are shown for
lllustratlon extending respectlvely from the rectlflers 189, 191,
193 and 195 to one of the six contact rollers 100 on the electro-
lytlc tanks 18, 20, 22 and 24. However, all slx contact rollers
100 on each electrolytlc tank are dlrectly connected to the same
bus bar. Bus bars 106, 202, 204 and 206 are shown extending re-
spectlvely from the same rectlfiers 189, 191, 193, and 195 through
cables 208 to one anode support bar 102 best shown ln Figure 5
mounted on the electrolytic tanks 18, 20, 22 and 24. Again the
respectlve anode bus bars contact each anode support bar 102
mounted on each electrolytlc tank connected to the bus bar.
As a result of the arrangement, dlscrete hlgh voltage
can be dellvered to each electrolytic tank 18, 20, 22, 24 as a
functlon of the metal platlng on the flbers 2 ln each electrolytlc
tank.
Practice has taught that the voltage in the flrst elec-
trclyte tank 18 should not be below 16 volts and seldom be below
24 volts. The voltage ln the second tank 20 should not be below
14 volts and the voltage in the third electrolyte tank 22 should
not be below 12 volts.
- 22 _ 1 3 2 3 32~
61109-7296D
Illustratively, fibers 2 have been coated in a system
of three rectifier-electrolyte tank assemblies, rather than the
four shown in Figures 1 and 15 under the following conditions
wherein excellent coating has resulted:
RECTIFIER 189 191 193
AMPS 1,400 1,400 1,400
VOLTS 45 26 17
The nickel metal coated fibers 2 produced under these
conditions have the following properties and characteristics:
Filament Shape Round (but dependent
on graphite fiber)
Diameter 8 microns
Metal Coating Approximately 0.5
microns thick, about
50% of the total
fiber weight.
Density 2.50 - 3.00 grams/cm.3
Tensile Strength Up to 45Q,000 psi
Tensile Modulus 34 M psi
Electrical 0.008 ohms/cm. (12K tow)
Conductivity 0.10 ohms/1000 strands/cm.
After the nickel plating has occurred, the fully plated
fibers 2 are delivered to the rinsing section 12 seen in
Figure 1.
132~328
23 61109--7296D
The drag-out section 42 and rlnse sectlon 46 are arrang-
ed with tanks to accumulate the dlscharge from the tees 44, 44A,
44B, 48 and 48A and both neutralize the dlscharge for waste dls-
posal and provlde a reposltory for accumulatlon of make-up for the
electrolyte tanks 18, 20, 22 and 24.
The apparatus ls arranged for synchronous operatlon as
shown ln Flgures 16 - 18. A motor 222 ls provlded to lnsure that
the contact rollers 100 best shown ln Flgures 5 and 9 and the
gulde rollers 51 rotate at the same speed to avoid abradlng the
fibers 2.
The motor 222 dlrectly drives an assembly of rollers 223
- arranged to effect a capstan. The rollers 223 are located ln thedryer 14 and as best seen ln Flgure 17 cause the flber to reverse
dlrectlon slx tlmes. The reversal ln dlrectlon ls sufflclent to
impose a force on the fibers 2 that will pull the fibers through
the apparatus without allowlng slack.
In addltion, the motor 222 ls connected by a gear and
chaln assembly to clrive each contact roller 100 and each guide
roller 51 at the same speed.
In essence, the gear and chain assembly is comprlsed of
guide drlve assemblles 225, best seen in Figure 1~ and contact
roller drive assemblles 227. Each
1323328
-24 ~
guide drive assembly 225 includes drive transmission
gear 230 mounted on shafts 231, a gear 224 fixedly secur-
ed to the guide roller 51 and a chain 233 that engages
the gears 230 and 224.
The contact roller drive assembly includes
drive transmission gear 239 mounted on the shafts 231
common to the gears 230, a gear 241 fixedly secured to
each contact roller 100 and a chain 243 that engages
both gears 239 and each of the gears 241 on the six
contact rollers 100 associated with each electrolyte
tank.
The location of the capstan rollers 223, seen
in FIGURE 18, in the dryer 14 enhances drying. The flat
surface and force applied to the fibers 2 spreads the
fibers and thereby accelerates drying.
The system also includes a variable speed
clutch override drive motor 219 for the take-up reels 17.
The force generated by the variable torque motor 219 pro-
vides the force to draw the fiber 2 through the system.
However, the capstan rollers 223 provide a means to
isolate the direct force imposed on the fibers 2 at the
take-up reels 17 from the fibers 2 upstream of the
capstan rollers.
