Lee Tunnel London protection scheme uses largest ever GIW pumps 09 July 2014

London's multi-million pound, high profile Lee Tunnel wastewater project, seen as critical to the protection of the capital's growing population from sewage overflow, has seen the installation of a huge pumping system 80 metres below ground.

The 54-ton heavy-duty, centrifugal slurry pumps – the largest ever made by specialist GIW Industries – will redirect up to 2.9 million gallons of sewage and rainwater per hour into the Lee Tunnel to prevent overwhelming London's 150-year-old Victorian sewer network, which can no longer cope.

They are regarded as essential to preventing an estimated 39 million tons of sewage and storm water from overflowing into the River Thames every year – which is why contractors went for an ultra-robust pump design capable of withstanding contamination and wear from foreign bodies contained in the sewage.

Part of that, according to Robert Visintainer, vice president of engineering for GIW, was the selection of spherical thrust roller bearings from SKF to meet critical performance demands.

"Our experience with the quality of SKF bearings and the technical support provided by their engineers has been outstanding," says Visintainer.

"Given the importance of this project and the demand for long term reliability, with pumps mounted 80 meters underground, GIW specified that only these bearings should be used," he adds.

In brief detaile, SKF type 29468 E bearings support main thrust loads, with SKF 32256 J2 tapered roller bearings handling radial load at the drive end of the shaft and any reverse thrust loads, while SKF 24080 spherical roller bearings support radial loads at the impeller end.

These pumps are mounted in a remote location 85 meters below ground, which means servicing the pumps would be a major undertaking in itself, but the tough SKF bearings minimise the likelihood of expensive downtime. SKF

SKF also produced four CircOil systems, which include accumulator run-down hydraulic circuits to protect the bearings in the event of power failure for two minutes so that the main pumps can be safely stopped without bearing damage. Two more have since been ordered.

"SKF's bearings prove that they can provide solutions for the toughest applications and meet critical performance demands in an exceptionally high profile installation," comments SKF application engineer Rolando Acevedo.

Brian Tinham

Related Companies
GIW Industries
SKF (UK) Ltd

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