Case study: Tower Bridge, London

Dorothea have had the pleasure of undertaking works at Tower Bridge previously. On this occasion we were called in to repair and replace the lubricators necessary for demonstration purposes.


City of London, Tower Bridge

Contract Type:

Manufacturing of Lubricators

Duration of contract:

4 months

Scope of works:

Replace bronze lubricators by casting and machining new components 


The original raising mechanism was powered by pressurised water stored in several hydraulic accumulators. The system was designed and installed by Hamilton Owen Rendel while working for Sir W. G. Armstrong Mitchell & Company of Newcastle upon Tyne. Water, at a pressure of 750 psi (5.2 MPa), was pumped into the accumulators by two 360 hp (270 kW)stationary steam engines, each driving a force pump from its piston tail rod. The accumulators each comprise a 20 inches (51 cm) ram on which sits a very heavy weight to maintain the desired pressure.

Works Undertaken:

The missing lubricators have been replace with new bronze ones cast and machined to match the existing sample. These lubricators are used to reduce the wear within the high and lower pressure cylinders during demonstrations. Even though the engine is only running on compressed air in lieu of steam the pressure required to run the engine still places strain on all the components.

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