Air-blown fibre is a method of installing fibre optic cables that relies on the flow of compressed air easing the fibre all the way to its destination - sometimes 1km away. A set of rollers or a caterpillar drive typically feeds the fibre into the tube.
Ideally suited to the Access Network ('The Last Mile') which compared to trunk routes has traditionally been difficult to plan due to intricacies of route and intermittent customer uptake. It was difficult to justify 24 fibres down a residential street if only 3 houses needed immediate connection. With blown fibre systems like fibreflow, a low-cost tube route is installed, and fibre only added as and when it is needed, creating a fibre-lean solution. And when a new connection is required, there is no need to re-dig the street...just select an empty tube and blow fibre in.
Fibreflow air-blown systems are replacing traditional optics in access networks around the world.
The benefits include:
- Reduced long term costs
- Much less splicing
- Less manpower
- Eliminates dead fibre
- Simpler network planning
- Easy quick upgrades in future
Fibreflow Blown Fibre takes the form of an ultra-lightweight single bundle of optic fibres designed for the access network ('The Last Mile') or campus. The fibre bundle is blown into a miniature duct system, using airflow, that takes it all the way to the customer premises without splicing along the way.
The Fibreflow System
Emtelle blown fibre solutions provide a passive infrastructure system based on small, light-weight, extremely robust microducts, and comprise the world’s most complete and advanced blown product range: fibres, tubes, microducts, bundles, subducts, main ducts and all related equipment and accessories.
The tube bundles come in various diameters and are normally configured in assemblies of 1,2,4,7,12,19 and 24. Other tube counts are possible. They are ideal for diverse inside and outside applications. Also included are fibre units and fibre cables optimized for air blown installation into the tube bundles: once the core infrastructure is in place – no need for expensive redundant fibre – future work can be executed simply and quickly. This allows our customers to upgrade or extend their network precisely in line with changing demands.
The fibre units provide fibre counts from 2 to 96 (single mode and multimode), meeting most last-mile requirements. Of course, blown fibre solutions are not limited to the last mile. For example, 96-way tube bundles can be used higher up in the network, an application for which Emtelle has developed a minicable solution – an example of how we develop new solutions to anticipate new challenges. A comprehensive range of accessories are also available including straight connectors, tube end caps, gas-block and water block connectors that provide an environmental seal between the fibre and the tube.
The fibreflow System in Action
The tubular route is in place. No more digging to do. The van arrives at the blow point wiht the equipment and the pan of fibre to be installed. The blowing head is linked to the first tube, and the air supply is connected. Fibre is bed into the blowing head. Thirty minutes later the fibre emerges at the far end, and can be connected at once. The customer can be 'on-line' the same day. There is fibreflow bundle to match each application, whether outdoors buried, overhead, in-building or elsewhere.
How Does fibreflow Work?
The working principles of fibreflow are simple and well developed. The pieces of equipment have been refined from user feedback, are easy to use and already have a long history of success, back to the 1980s.
The blowing theory is based on airflow acting as a carrier in the tube. The air flows over the fibre at high speed and thus imparts no tension or stress on the fibre. The air supply is dried to the correct level and supplied down a plug-in hose. Fibre unit is deployed stress-free from a pan, permitting access to both ends of the fibre. The blowing head is very small and reliable, and easy to set up. It drives the fibre forward and measures speed, while also feeding in the air supply.
Tube routes are quickly created using push-in connectors for links and branches: This eliminates fibre splices wherever cables meet. A fibre can be blown through such a route typically in 20 or 30 minutes. At the far end, the air is back to normal pressure, very safe, and the fibre emerges stress-free, gel-free, ready for connection in minutes.
There are a range of extending methods, which mean that 5km or 6km of fibre can be blown in a single unbroken length, minimising splices and optical losses. It is easy to plan a blow route, once it is decided what tube size and fibre count are to be used. Manholes or access points can easily be planned for the whole access network.
The modular system means that to add a customer to an existing route is much simpler and cheaper than with traditional optical networks, with typically no need to re-dig the main street