Compound Steam Engine
Opened in 1894, Tower Bridge was one of the finest examples of the practical application of steam-generated hydraulic power. It was initially equipped with two compound steam engines, one of which is seen above, preserved as an exhibit for those touring the bridge today.
The roadway sections of the bridge that open weigh over 1,000 tons. To open the bridge in a smooth, controlled manner took a considerable amount of power.
The engines were located in the vaulted engine house on the south side of the River Thames. Each engine drove two sets of hydraulic ram pumps which forced water into hydraulic accumulators. The water was stored at a pressure of 750 psi, ready to be delivered through a system of pipes to the eight hydraulic engines. There were four on each side and they were located in the bases of the two main towers of the bridge.
As with most Victorian plant, there was plenty of spare capacity. The bridge could be opened using only one of the steam engines and two hydraulic engines.
A cog wheel on the main shaft of the hydraulic engine engaged in a quadrant attached to the bascules, so effecting the lift. For one descent of the plunger in the accumulator, the bridge could be opened and closed twice. Thus when the bridge was opened infrequently, an engine only needed to work intermittently. On busy days, one steam engine would be kept running continuously at 10–15 rpm, keeping the accumulator topped up at all times.
A third steam engine was added to the arrangement in 1941. When the bridge was converted to electrical power in 1974, this third engine was removed to the Forncett Industrial Steam Museum in Norfolkshire where it can still be seen today.
The engine and room are very colourful, but I felt that this distracted from some of the engineering detail, hence the monochrome image above.
Compound Steam Engine
Opened in 1894, Tower Bridge was one of the finest examples of the practical application of steam-generated hydraulic power. It was initially equipped with two compound steam engines, one of which is seen above, preserved as an exhibit for those touring the bridge today.
The roadway sections of the bridge that open weigh over 1,000 tons. To open the bridge in a smooth, controlled manner took a considerable amount of power.
The engines were located in the vaulted engine house on the south side of the River Thames. Each engine drove two sets of hydraulic ram pumps which forced water into hydraulic accumulators. The water was stored at a pressure of 750 psi, ready to be delivered through a system of pipes to the eight hydraulic engines. There were four on each side and they were located in the bases of the two main towers of the bridge.
As with most Victorian plant, there was plenty of spare capacity. The bridge could be opened using only one of the steam engines and two hydraulic engines.
A cog wheel on the main shaft of the hydraulic engine engaged in a quadrant attached to the bascules, so effecting the lift. For one descent of the plunger in the accumulator, the bridge could be opened and closed twice. Thus when the bridge was opened infrequently, an engine only needed to work intermittently. On busy days, one steam engine would be kept running continuously at 10–15 rpm, keeping the accumulator topped up at all times.
A third steam engine was added to the arrangement in 1941. When the bridge was converted to electrical power in 1974, this third engine was removed to the Forncett Industrial Steam Museum in Norfolkshire where it can still be seen today.
The engine and room are very colourful, but I felt that this distracted from some of the engineering detail, hence the monochrome image above.