Note: Descriptions are shown in the official language in which they were submitted.
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B~-K~ROUI~D 7~0 1~ lVI;MTI~N
This invention relates to a me~n.s for preventin~ mois~
ture ~rom coming in contact with electrical components in a con-
tainer. More particularly, it relates to an improved telephone
S cable splice case, which is readily re-enterable.
In the t~lephone communication industry, signals are
transmitted many miles over cabl~ containing many pa-rs of con-
ductors. Since this cable is sold in fixed lengths, usually
several hunclred feet each, it is necessary to splice cables to-
gether. The ends of corresponding conductors o~ ~butting cables
are tied or spliced together after their insulations have been
trimmed, exposing their metallic conductors. In order to protect
these exposed rnetallic conductor splices frGm the elements, such
as moisture, the splices are housed in a splice case. If the
cable is an air c~re type, which is normally used above ~round on
telephone poles, the splice case is usually under air pressure,
and thus air acts as a filler in the splice case to Xeep out
moisture. However, recently it has become a common practice to
bury telephone cable underground. Moisture is a major problem in
buried cable. To solve this problem, the industry uses a heavy
grease filling in the core of buried cable. The splice case
commonly used for buried cable is normally a jel compound which
sets up after it has been injected into the splice case to form a
~hard rubber filler in an attempt to seal the case. One of the
problems in using this type of rubber-filled splice case is that
it is very difficult to re-enter the splice case to make repairs
~on the splices. The rubber itself must be cut through in order
to get to the splicesO Furthermore, once the rubber has been cut
through, the fill material is often rendered useless, thus it
must be re-filled or a new splice case must be used.
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~:urthermore, ome moisture problems have occurr~d in
this type of filled splice case in that the r~bber material will
not hond to ~3rease coatcd polyethy]ene telephone conductor; thus,
when the rubber sets u~, it o~t~n leaves a gap betw~en the indi-
vidual telephone conductor and the rubber itself which leaves a
channel or moisture to move th~^o~gh to àttack the splice, and
thus degrad~ the conductor.
Examples of filled splice cases are showr. in V. S. Pat-
ents 2,312,652 and 4,070,543.
Various electrical apparatus such as transformers have
been housed on containers which are substantially filled with
light oil. In the case of the transformer, the oil is used to
keep the coils cool as well as provide insulation to prevent
shorts. I~ormally, transformers are located on poles above
ground. Electrical power lines normally enter the transformer
bGx from the top and make connections to the windings of the
transformer, which are immersed in oil. The oils which are used
in the transformer box have a specific gravity of less than 1, as
do almost all oils.
High voltage capacitors have used oils as a diele~tric
,; material. An example o an oil used in disclosed~Dow Chemical
Product Bulletin titled Dow Dielectric Fluid C-4, form No.
17.6-1347-78. The C-4 fluid is butylated monochlorodiphenyl
oxide and has a specific gravity o~ 1.095.
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OBJECTS OF THE INVENTION
It is one object of this invention to provide a case
for housing electrical components with improved moisture sealing
features.
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It is another object to provide an improved
cable splice case.
It is still another object to provide improved
cable splice case which substantially prevents moisture
from coming in contact ~ith the splices.
It is another object to provide an easily
re-enterable splice case.
SUMMARY OF THE INVENTIO~
In accordance with one form of this invention,
there is provided an electrical ca~le splice case,
including a container housing electrical wire splices.
Cable entry holes are located above the splices and
receive electrical cables. A fluid sealant is received
in the container, and covers the splices. The fluid
sealant has a specific gravity greater than 1. If water
should enter the container, the waker will remain on top
of the fluid sealant, placing hydraulic pressure on the
fluid, thereby increasing the intimacy of the seal
between the fluid and the splices. Normally, the fluid
will be an oil, which is substantially insoluble with
water.
In accordance with another form o~ the inven-
- tion, the splices set forth above are replaced with
other electrical components, but are protected from
moisture by immersing them in a fluid with a specific
gravity greater than one, similar to splice protection.
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According to a further broad aspect of the
present invention there is provided an electrical splice
case including a container housing electrical wire
splices with entry holes located above the position of
the splices. The entry holes are for receiving electri-
cal cable. The improvement comprises a fluid sealant
received in the container and covering the splices. The
fluid sealant is substantially a silicone oil having a
specific gravity greater than 1, whereby if water should
enter the container, the water will remain on top of the
fluid sealant, placing hydraulic pressure on the fluid
sealant, thereby increasing the intimacy of the seal on
the splices.
BRIEF DESCRIPTIO~ OF THE DRAWI~GS
The subject matter which is regarded as the
invention is set forth in the appended claims. The
invention itself, however, together with further
objects and advantages thereof, can
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~e better un~er.tooc] by referel~ce to the following description,
taken in conjunctiol) with t}le accompclr~ying drawing in which:
the fiyure is a cross-sectional elevational view of a
cable splice enclosure showing one forln of the present invention.
S Dr~sc~JpTIoN OF ~ PREY~ RED E~O~I~IE~'r
Referring now snore particularly to the figure, there is
provided a ca~le splice system 10 which includes splice case 12
having a bottom or pan portion 14 which includes four sides and a
bottom. The splice case ~urther includes top portion 16 which
acts as a cover for the splice case. The cover is secured to the
bottom portion o~ the splice case by means of screws 18 and 20.
Also, slip-on spring fasteners may be used over the cover and the
bottom. A ru~ber seal 22 is located between the cover and the
bottom covcr of the case to inhibit moisture ~rom entering the
case. A pair of cables 24 and 26 enter the s~lice case throuyh
holes 28 and 30 in the cover. Raised portions 32 and 34 also
receive the respective cables 24 and 26 and act as a seal to
inhibit moisture from entering the splice box through the cable
entry holes. The entry ports may ~lso be positioned through the
sides of the case at a downward angle so that the cable need not
be bent so much.
As can be seen, the corresponding individual insulated
conductors 36 and 38 of the respective cables are spliced togeth~
er as indicated by splices 40 by a method known to those skilled
in the art. The insulation from the individu~l conductors are
first stripped from the ends to permit a splice, thus exposing
the ends of the conductors to the elements outside of their in-
sulation. ~lso~ insulation piercing connector may be used. One
major problem, as stated previously, particularly in using under-
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groulld splic~s, l~as becn that moisture could attac~ and deyrade
the e~los~d ~etallic conductors ~hcre they are splicc-d. In order
to overcollle this prob]em, the-e is included an arnount of â fluid
of 42 in the sL~lice case, which completely covers the individual
splic~s. In one embodiment o this invention, the fluid is an
oil and the pr~ferred oils are silicone ~luids, such as Dow Corn-
in~ 230 fluid, being methyl alkyl polysiloxane, commercially
available from Dow Corning Company, and another is General Elec-
tric SG 1080 methyl alkyl polysiloxane silicone f]uid, available
from the General Electric Company. The fluid 42 should be a good
electrical insulator with goo~ dielectric strength. It is pre
ferable that the fl~id be substantially insoluble with water,
and, most importantly, it must have a s~ecific gravity greater
than l, that is, a specific gravity greater than water. The Dow
Corning 230 fluid has a speci~ic gravity of from 1.006 to 1.012
at 25~C. Other electrical fluids which have a specific gravity
greater than one, and have proper insulation characteristics will
âlso provide the desired results. The oil should not chemically
attack the cabLe or the splices.
Since material 42 is in the fluid state, in order for
it to be an effective seâlant for splices 40, the fluid covere~
splices 40 should be lower than the cover portion 16. Thus the
fluid 42 will not readily run out the entry ports 28 and 30. The
need for fluid to have a specific gravity greater than l will
become more apparent below.
In the event that water were to en~er the splice case,
say, for example, through seal 22 or through the entry ports 28
or 30, it would accumulate on top of the sealant fluid in the
space indica~ed at 46. E~en if the mois~ure were to come in
through the ends of the cable 48 and 50, since the fluid is
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preferabl~ sub~t~ntially insolubl~ in watcr and sinc~ it has cl
speciic gravity greater than w2ter, the water wo~ld tend to
ascend to the top of the fluid, and again, accumulate in space
46. ~?ith ~he watcr now on top of the seal~nt fluid, gravitati~n-
S al effects woulcl cause hydraulic pressure from the water to press
down on the fluid, creating an even tighter seal about the
splices 40 from the now pressurized sealant fluid. Th~s, quite
unexpectcdly, the entry of some water into the splice case ac~u-
ally enhances the seal and protection of the individual splices
40, which are immersed in fluid sealant 42.
The splice box itself may be made of metal or plastic.
The c~bles are ordinary multi-pair telephone cable. The seals
are ordinary ru~h~?r seal;, and the splices are made as other
splices have been done by those s~iilled in the art.
Experi~ental laboratory splice cases as suhstan~ially
described herein have been constructed and tested. A pyrex beak
er was partially filled with Dow Corning 230 fluid and tensil
bars were added. These bars were made of, respectively, polyeth-
ylene, polypropolene, and polycarbonate, whcih are telephone
cable and splice materials. The tensil bars were heated at 100~
for five days. The tensil strength of the bars was tested, and
there was no change in tensil or elongation. In another test, a
110 volt light bulb was in~ersed in a top open container housing
the Dow Corning 230 fluid. This open container, with the top
off, was immersed in a large container of water. The water came
into contact with the top of the oil. The bulb was connected to
an A.C. source. The bulb was left on for 48 hours with the bulb
insulated from the water with no aegradation.
The application of this invention could further be ap~
plied to other elec~rical and electronic devices which are housed
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hous~d in boxes where Inoi.,ture L~en~tration is a probleln. I~xam~
ples are spliccs which feed an under~3round ~o~er ee~er to dis-
tribution cahle, ancl electronic circ~it c~rds~ which are housi~cl
in a riepeater housing, wherehy the electronic components and
connections are maintained within the ~luid having a specific
gravity greater than one.
From the foregoing description of the embodiments of
the inventioll, it will be apparent that many modifications may be
made therein. It will be understood, however, that this embodi-
ment of the invention is intended as an exemplification of the
invention only, and that the invention is not limited thereto.
It is to be understood, therefore, that it is intended, in the
appended claims, to cover all modifications that fall within the
tr-ue spirit and scope of the invention.
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