Hydraulic seals operating to perfection on Thames Barrier

If there’s one thing that is guaranteed, absolute and total reliability is required from the hydraulic cylinders that lift the Thames Barrier’s massive gates to protect London against surge tides or flooding.

For over 35 years, James Walker hydraulic seals have worked perfectly and have recently been replaced as part of their routine maintenance schedule in the cylinder refurbishment – 15 years since the last replacement back in 2009.

The 16 sets of hydraulic seals operate in the heat of summer and in freezing winter conditions, to open and close the Barrier’s four main 3300 tonne gates.

Each cylinder uses a Solosele® G single element seal with a block ring, and a Twinset packing set, all of 1.1 m OD, plus a Chevron® multi-lip packing set of 431 mm OD.

At the last round of replacements, used seals were examined by James Walker experts to determine their condition and all were found to be within the customer’s original tolerance limits and in good working order.

Similarly in 2024, there was little evidence of wear or damage to the seals.

Geoff Teasdale, Product Manager for heavy duty hydraulics, explains that only top quality sealing products can survive for such prolonged periods on the Thames Barrier.

“These are the worst possible working conditions for hydraulic seals,” he said. “They sit in the same position during long periods of inactivity – then must work faultlessly when needed.”

Each time the Barrier is raised, 125 km2 of London is saved from a tidal surge that could affect over 1.25 million people, homes, offices and vital infrastructure.

Geoff concludes, “Under such conditions, only the best and most proven seals can be used. Lesser quality products cannot be tolerated.”