Suspension clamps for OPGW

Hardware& Accessories for Optical Fibre Aerial Cables

Metal-armored (OPGW, OPPW) aerial cables with integrated optical fibers are used to transmit information .The information is transmitted by means of modulated light pulses in the interior of the thin optical fibers. These fibers have a total diameter of approx. 300 µm. Such cables can be stressed up to a limited tensile force without any increase of the optical signal damping in the fibers. However, in the case of a radial force, the optical damping will increase by bounds. This increase can lead to a reduction of the information flow through the fibers.

The fibers with an additional length are in one or several relatively rigid coaxial tubes to avoid inadmissible stress. The core(tube) of the aerial cable is covered with one or more layers of aluminium alloy wires or Aluminium-clad steel wires.

As the optical fibres have to be protected against inadmissible radial forces during and after the installation of optical fibre aerial cables the fittings at the tension-, suspension- and fixing points have to meet special requirements.

The common fittings for tension and suspension points which provoke the necessary griping force by effecting of a high radial force (for example wedge type tension clamp, suspension clamp). Due to the high pressure sensitivity of optical

fibers , these types of fittings are not suitable for optical fibre aerial cables.

The preformed helical fittings are designed which are especially adapted to this purpose. The induced radial forces are spread over a larger contact surface (for example dead end) in such way that the fibers are not stressed and the necessary griping forces are achieved.

Fittings for optical fibre aerial cables mainly consist of the following group of fittings:

- Preformed Helical fittings for tension and suspension points

- Earth connections

- Tower down-lead accessories

- Vibration dampers

The principle of operation of preformed helical accessories is based on the principle of the development of a low pressure over a large area. The inside diameter of the unloaded helical rods is slightly smaller than the outside diameter of the optical fibre aerial cable By wrapping the helical rods on optical fibre aerial cable, a spring tension is created, producing the necessary

frictional contact. This spring tension is elastic and ensures a constant grip.

To ensure the full performance, helical formed accessories must exactly be adapted to the outside diameter of optical fibre aerial cable .

We, Key Link will give you a good solution and performance .

Suspension clamp for OPGW

• Product introduction

     The armor grip suspension is used for the movable suspension of OPGW on suspension towers. The whole sets is composed of a certain number of preformed helical rods:one inner set for protecting and another outer set for fixing, a concave rubber insert consisting of two halves and a clamp body. The helical rods are placed in and out of rubber insert at the suspension point.

    The armor grip suspension - like the application of suspension clamps along with armor rods - does not impede asymmetric vibration and thus avoids local alternating bending stress. This is no static compression force existing in standard suspension clamps with and without armor rods due to the keeper with bolts. This is the principle difference of the armor grip suspension compared to suspension clamp commonly used up to now. The reinforcement of the cross-section by armor rods improves the lifetime of the vibrating OPGW cable. However, it is no damping device to cope with OPGW cable vibrations.

    The electrical connection of the helical rods and the suspension equipment is resistant to short-circuit current, i.e. it is capable to conduct the short circuit current of OPGW cable without damage.

• Product specification

1. Inner protection armor rods:Aluminum alloy.It wraps outer layer of OPGW

2. Outer preformed helical rods:Aluminum alloy, wraps and fixes on the rubber insert

3. Suspension clamp set: includes rubber insert,(b) aluminum housing,whole bolt sets; Rubber insert: high quality rubber and with center-reinforcement,has high strength,good elasticity and low compression deformation.Aluminum housing is formed by pressing and forging corrosion resistant aluminum alloy.

4. Earthing wire: AAC cable , with aluminum alloy plug pressed on , one set parallel groove clamp , and one set bolt assembly

• The respective letters or figures have the following meaning:

O: OPGW cable;

X: Suspension clamp

Y: Preformed type

First 4 figures group : largest possible cable diameter for which the accessory is suitable (measurement: 0.01mm)

Last 2 or 3 figures group : Rated tensile strength of whole assembly set for which the accessory is suitable

(measurement: KN)

1. Application to RTS≤70KN OPGW,the broken strength:70kN；holding strength 14%-20%RTS

2. Application to 70KN≤RTS＜100KN OPGW,the broken strength:100kN；holding strength 14%-20%RTS

• Application to 100KN≤RTS≤120KN OPGW,the broken strength:120kN；holding strength 14%-20%RTS