Fume Extraction System Helps Train Rail Welding Operatives

Two bespoke fume extraction systems using TEKA extraction equipment, both with four specially designed hoods from Flextraction are helping Network Rail in Bristol to train and certify future operatives in the techniques of aluminothermic welding, manual metal arc (MMA) and semi automatic and automatic flux cored arc welding (FCAW) techniques, as used in rail welding operations.

Network Rail has training facilities throughout the UK, with the older ones being replaced by new modern facilities to create a learning environment that simulates the real world, whilst at the same time is conducive to learning and providing a sheltered area to allow the trainees to maximise their learning potential. At Bristol, Network Rail train and re-certify staff employed in rail welding operations and also in the handling and using of small plant and inspection training.

The system ordered by Track Line Contracts Ltd, a Network Rail contractor, was specially designed for aluminothermic welding. It comprised a TEKA Filtercube 4H filter module with a 100m² filter area that is designed as a central suction unit for several welding points. It extracts polluted air using a ventilator to a filtering section; here any toxic particles are deposited on the surface of filter cartridges, which are de-dusted automatically using compressed air. The toxic particles are then collected in a tank and clean air is recycled to the workplace.

A TEKA ‘Spark Pre-Separator’ uses a water mist curtain to protect the filter device from fire. Two 3-phase centrifugal, single inlet, high pressure fans equipped with silencers were installed to extract the fumes from the point of welding to the filter unit. The four hoods, supported on heavy duty beam trolleys, were specially designed with 1000mm diameter canopies and side screens. The complete system, including spiral galvanised sheet steel ductwork, 48m of hose with light duty beam trolleys to support the hose, was installed by Flextraction Engineers.

Network Rail at Bristol also trains operatives in MMA and semi automatic and automatic FCAW techniques, which is where another Flextraction extraction system comprising a Filtercube 4H filter module with 4 x standard 4m Hood Positioning Devices (HPD) arms, each with 1m extensions and 150mm diameter flared hoods, is also in constant use in the welder training school.

Lee Janczysyn, Training Delivery Specialist (Welding and NDT) said: “Network Rail uses MMA and semi automatic and automatic FCAW techniques, in addition to aluminothermic welding. Both Flextraction systems are used for training purposes and the system for aluminothermic welder training has been very good, easily removing the fumes, whilst the spark box extinguishes all sparks before going through the filtration system. This system was installed in a building that was already constructed, so there were some constraints to its location, which were overcome.

There are two tracks each with two hoods designed to be moved along the track to the correct position for welding with two of them operating at any one time; however, we only ignite one welding portion at any time so that the welding trainer can supervise one activity at a time. In general we find the system easy to use; it has self cleaning filters and only requires the press of a button to start the extraction operation.

The other system in the welder training centre also works effectively and our trainees find the HPD arms easy to position.”

Lee Darton, General Manager Sales at Flextraction commented: “With the system for aluminothermic welding, we made some modifications during the installation to meet the requirements of both the contractors and Network Rail due to the constraints of the building, otherwise the systems was delivered as required. It is self cleaning with the filters occasionally need changing, which will be undertaken by us. It also has a second motor as a back up allowing the system to be used if the primary motor should fail.”