DE8507698U1 - Fiber optic cables - Google Patents

Description

KABELWERKE REINSHAGEN GMBH WUPPERTAL Wl [I UM I) K ^ IM

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Fiber optic cable 1.

The invention relates to an optical fiber cable according to the Preamble of claim 1.

The invention has for its object to provide a LicKtwellenleiterkabel for the operating temperature range of about -55 C to +125 ⁰ C.

This object is achieved according to the invention by a duct structure according to one of the claims. Details of the invention J can also be found in the description.

The fiber optic cables of the invention are special suitable for use in aviation. They are metal-free, light, insensitive to any electromagnetic Influence, radiation-resistant and tensile strength.

In Figures 1 and 2, two embodiments of the invention are shown.

The description of the fundamentals following the description of the figures relates to Figures 3 ■ and 4.

In Figure 1 is a glass fiber 1 with a precoat not shown in detail. (Coating) provided. Above that is one Silicone elastomer layer 2 is extruded. Layer 2 is of a layer 3 made of glass fiber reinforced ETFE (ethylene-tetra-fluorine-ethylene) covered. A braid 4 made of polyaramid fibers is applied to this for strain relief. as Outer jacket 5 is a layer made of ETFE. In FIG. 2, the reference symbols are increased by 10. The characteristics agree with those of FIG. 1 except for the outer jacket 15. The outer jacket 15 consists of one layer banded and sintered polyimide film, which under the Name KAPTON is in the trade.

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StU of the company: WupperlalRontdorl Chairman of the OaseüirtsftUviine: Or. Funk OotM ReinslugenslraM I Ot «ch« Heluh <«r and slwlv chairman: HM« / UMnunri S600 Wuppertal 2 t Representative OtSdMrlshilutr: MMaII HwiMtr RuI 102 021 46 69-1 ■ · im!> ·· «· Hvu-Peter SenOtM Tele «0SS9M64 krwd Ί."! ..!!. '! ..',! '·· * DtrH-KIm Htrm-Mt * «w * ~ r Register court: Wuppertal district court. MBO 22 »YY · · Y ·" YY · Vorilttender dn AufsKMoam: OrAKMnMrAMeM

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Fiber optic cable for operating temperature turberdich '· Υ, ν "2? 3-ΟΕ from -55 ° C to + 125 ° C' .. '''··''· * ··"_; ₂ _

The mechanical basis for a fiber optic cable for the operating temperature range from -55 "C to + 125 ° C is presented. The single fiber cable consists of a fiber with precoat, which is surrounded by a silicone elastomer. This substructure is covered with a glass fiber reinforced fluorothermoplastic. The thermal The expansion coefficient and the shrinkage of the fluorothermoplastics are very low compared to conventional thermoplastics. Shrinkage is an irreversible reduction in volume of thermoplastics, which occurs when the thermoplastic is reheated after the extrusion. To increase the tensile strength _.: And to relieve the strain on fiber optic connectors attach ■ ', a Aramidgeflecht is applied. fluoro i thermoplastic (ETFE) or banded and sintered polyimide film serves as the outer jacket. f

Preliminary tests have shown that the positive temperature range (+ 125 * C) is not critical for the attenuation behavior of the optical waveguide due to the mechanical behavior of the thermoplastics. A pressure relief element is necessary for the negative temperature range, the mechanical pressure in the longitudinal direction of the cable caused by the shrinkage and thermal expansion behavior of the jacket materials arises, at least partially absorbs.

G. Powers, in a 1983 publication, viewed the fiber optic cable as a rod to which pressure is applied. If the rod is surrounded by an elastic medium with the modulus of elasticity Ej, the rod buckles at a critical compressive force F _CR . Mathematically, there is the following relationship:

^F CR - * ^a , V * ^E l ^E F (1)

r - radius of the optical fiber (fiber) Ey - - Ε module of the LWL (fiber) Ej - Ε module of the first shell

with F = εΕΑ holds

= 7 Ε _χ / (π Ep). ₍₂₎

- Amount of contraction of the fiber by the force F _cr .

^E r denotes the amount for the thermal contraction of the entire fiber optic cable. The shrinkage of the fiber optic _cable is denoted by e sch. If ε _ΟΓ > (ε _Γ + s _sch ), _S o the fiber does not buckle.

If ^e cr < ( ^E r + ^e sch), a force greater than F _CR acts on the fiber and causes it to buckle.

The kinked fiber presses itself spirally into the surrounding medium. The curvature of the spiral leads to an increased damping of the Optical fiber.

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LN 223-DE

For ^Ecr " * · ^ε γ ^xt sch ^/ a critical minimum temperature T _CR can be calculated, at which the fiber is loaded by the expansion behavior and the shrinkage of the cladding materials with such a great compressive force that the fiber just begins to buckle. For a structure with a buffer layer and an outer jacket, the following applies to the critical temperature T _rR :

^L cr

- ( ^E cr - ^e sch ₂ )

2 A ₂ ) / (a ₂ - ^a F)

The shrinkage and expansion behavior of the buffer layer compared to that of the outer jacket are neglected. If an aramid strain relief and a thermoplastic outer jacket are applied to this construction, the critical temperature T _{CR is determined} using the following equation:

Ej It A I *

E ₂ A ₂

T ¹ = T ^x cr ¹ O

The expansion coefficient of the strain relief mesh remains disregarded. A combination of material parameters and cable dimensions can be selected using equation 4, at which the critical temperature is as low as possible. The feasibility and the effects on the damping behavior must be observed of the fiber optic cable must be taken into account during the manufacturing steps. The mechanical parameters of the used.! Sheath materials are summarized in a table. For the realized constructions of the types 68-3 and 68-5 there is no The strain relief element and outer jacket each have a critical temperature of -175 "C. The maximum compressive force is 18.4 N each.

With additional strain relief and a thermoplastic outer jacket, the critical temperature of the 68-3 type is -47 * C. This means that this construction is very sensitive for the temperature range down to -55 * C. Measurements show an increase in attenuation of 20 dB / km in the temperature range. The damping behavior can be improved by reducing the wall thickness of the outer jacket. However, this results in difficulties in production because the outer jacket can easily tear open when it is applied to the strain relief braid. If the outer jacket is replaced by a polyimide film, the wall thickness of the outer jacket and its mechanical effect on the damping behavior are reduced. The change in attenuation in the temperature range up to -55 "C is 2.3 dB / km. The calculated critical temperature T _CR is -136" C.

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LN 223-DE

The parameters of the jacket materials used for the equation are compiled in a table, those shown in their purest form Structures have been calculated the critical temperature and critical force.

The FicT. 3 and 4 show the cross-sections of the samples produced. Further tests such as B. are required when using the cables in aircraft, are currently being carried out. The cables are metal-free, light and therefore insensitive to any electromagnetic Influencing.

Structure of the fiber optic cable in Fig. 1:

1 ^ Xiichtwellsnleiter

2) silicone elastomer

3) Glass fiber reinforced ETFE

4) Braid made of polyaramid for strain relief

5) Outer sheath made of ETFE

y / vs / ** ImTt 0 0.66 mm 0 1.8 mm

0 2.0 mm 0 2.4 mm

Structure of the fiber optic cable according to Fig. 2:

11) Optical fiber 0 0.5 mm

12) silicone elastomer 0 0.9 mm

13) Glass fiber reinforced ETFE ^a) 0 2.0 mm

14) Braid made of polyaramid

for strain relief 0 2.2 mm

15) Outer jacket made of banded

and sintered polyimide film 0 2.6 mm

Note a)

The proportion of glass fibers is approx. 25%. The material under the name

TEFZEL 7OG-25 sold thermoplastic

Processable fluoroplastic made by the company

DU PONT are used. However, there are too

other plastics can be used for which

the glass fiber content is around 10 to 40%

can.

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LN Z23-DE

Table 1)

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III

■ t

• »JII

• ■ II *

Material E * slit am

material

a / ° C

E / GPa

^E sh '

Quartz glass

ETFR

ETFE gfv

silicone

Polyimide

Aramid

0.5-10 " ⁶ 90-10" ⁶ 30 x 10 " ⁶

27-10

-20-10 " ⁶

70

0.825 2.25 0.004 3

0.8

0.1

0.30

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LN 223-DE Table (2)

ι · · ■

Structure, without strain relief and outer jacket

a _v m 5-10 " ⁷ 1 / K

, -5

a ₂ = 3-10 " ³ l / K

F _cr = 18.38 N

0 _F = 0.28 mm

01 = 0.9 mm

0 ₂ = 2.0 mm

E _F = 70 GPa

E ₁ = 4-10 " ³ GPa-

E ₉ = 2.25 GPa

-175.3 ⁰ C

Structure with strain relief and ETFE outer jacket

a _F = 5-10 " ⁷ l / K a ₂ - 3-10-5

" ⁵

0 _F = 0.28 mm 0! = 0.9 mm

0 ₂ - 2.0 mm

0 ₃ = 2.2 mm 0A = 2.6 mm

E _F »70 GPa

E ₁ = 4 * ΙΟ " ³ GPa

E ₂ = 2.25 GPa E _A = 0.825 GPa

= 9-ΙΟ " ⁵ l / K

F _cr = 18.38 N T _cr - -46.7 ⁰ C

Structure with strain relief and outer jacket with polyimide film , -7

<x _p - 5-10 " ⁷ l / K a ₂ - 3-10-5

2.7-10 " ⁵ L / K - 18.38 N ' -136.4 ° C

0p »0.28 mm

01 - 0.9 mm

0 ₂ - 2.0 mm

0 ₃ - 2.2 mm 0 /. = 2.3 mm

E _F = 70 GPa

E ₁ - 4-10 ^"3 GPa

E ₇ - 2.25 GPa 3.0 GPa

^E sch2

0.1%

^D sch2

^E sch4

0.1%

0.8%

^E sch2 - °. « ^E sch4 = 0.35Z

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Claims (5)

KABELWERKE REINSHAGEN GMBH WUPPERTAL LN 223-DE -7- 1 3J. 31 t> claims 1. Optical fiber cable off an optical waveguide made of a glass fiber that is connected to is provided with a protective layer, a covering of an elastic layer ^ - r a pressure-resistant layer, a tensile layer and an outer layer as a protective sheath in which all the layers to one another are fixed, characterized in that the pressure-resistant layer <~ \ consists of a material having a shrinkage = 0.1% and an expansion coefficient χ 3 = 10 / K has. 2. fiber optic cable according to claim 1, characterized in that the material is a plastic. 3. Lichtwellenlei .zerkabel according to claim 2, characterized in that the plastic is glass fiber reinforced. 4. fiber optic cable according to claim 2 or 3, characterized in that the plastic is a O is fluoroplastic. 5. fiber optic cable according to claim 4, characterized in that the plastic is a thermoplastically processable fluoroplastic. -8th- Site of the company- Wuppertal-Ronsdorl Chairman of the Management Board: Or. Frank Ooihe Relnshaganstrafla I Geachattatuhrer and ilen ». Vora .: Heini Allemann 5600 Wuppertal 21 Qesehimturirer: Or. Oerd Apratn RuI (02021 4869-1 Helmut Henlller Telen 1591464 kn »d _{M tll |} ,, _tif> ,, ,, ,, Olpl.-Klm. Hana-Jorgen Fu la 10202) 4669777. ι ι · · · '■ ι ι ι ■ Voraitundef dea Aulalctitaralea: Or. Ale> other A mile nem: AmllOiflehl Wuppertal. HREi ilft '",]',, ' !".'■,!>"·: T ι ι r ι it ι ι -ι