"B" Station Turbine Basement
East side of "B" Station Turbine Basement
Although plans to extend the northern end of "A" Station were proposed as early as 1929, construction was delayed for nearly a decade due to the ongoing economic impacts of the Great Depression.
Work finally commenced in September 1935, beginning with the construction of the concrete raft foundations for the new "B" Station. This involved driving 710 piles into the ground to a depth of 10 metres to provide stable support. The building itself was constructed using a steel framework with reinforced concrete walls, floors, and a flat concrete roof supported by parallel chord trusses.
Unlike "A" Station, there was no internal wall separating the two sections of the power station. The contrast between them is clearly visible today, reflecting the different architectural styles from the time each was built. One noticeable difference is that, unlike the earlier "A" Station, the exterior design of "B" Station no longer expressed the scale or form of the large internal spaces such as the turbine hall and boiler house. Instead, the external walls were more streamlined and industrial, with less emphasis on reflecting the interior layout.
No. 6 Surface Condenser
East side of "B" Station Turbine Basement
Surface condensers are an essential part of steam turbine systems in thermal power stations. Acting as large heat exchangers, their role is to convert exhaust steam from the turbines back into water by transferring heat to a separate cooling water system.
This particular cast iron surface condenser was manufactured by C. A. Parsons & Co of Newcastle-upon-Tyne and commissioned in 1938.
The No.6 condenser is made of fabricated steel with horizontally mounted cast iron waterboxes at each end. Cooling water flows through hundreds of brass tubes, each measuring approximately three-quarters of an inch in diameter. These tubes are secured in place by plates located between the shell and the waterboxes. The cooling water passes through the steam space in two horizontal passes, efficiently absorbing heat from the steam.
At full load of 25 MW, the condenser circulates around 4.5 million litres of water per hour, with the cooling water temperature rising by about 9°C during the process (Tweedie, 1994).
Importantly, the steam and cooling water remain completely separated by the tube walls, allowing heat to transfer without the two fluids coming into contact.
Due to the larger size of this condenser compared to earlier units, the basement floor had to be lowered to accommodate it, while maintaining the turbine hall floor level consistent with the adjacent "A" Station.
No. 6 Lube Oil Coolers
East side of "B" Station Turbine Basement
Manufactured by C. A. Parsons & Co of Newcastle-upon-Tyne and commissioned in 1938.
To reduce friction and wear, the turbine and generator bearings required a continuous supply of lubricating oil. As the cool oil circulated through the bearings, it absorbed heat generated by the high-speed rotation of the shafts.
The lube oil cooler functioned as a shell-and-tube heat exchanger (a series of tubes inside a large cylindrical shell). Hot oil from the bearings entered the cooler on the tube side, while cooling water from the station’s condenser flowed through the shell side. The water extracted heat from the oil, allowing the cooled oil to be recirculated back into the bearings.
No 6 Turning Gear Oil Pump
East side of "B" Station Turbine Basement
Installed in 1938, this pump played an important role in protecting the turbo-alternator (the machine that generates electricity from steam) when it wasn’t running.
After the turbine was shut down, the metal parts inside were still very hot. Because there were tight gaps between moving parts, the shaft—a large spinning rod inside the turbine—had to keep turning slowly for up to three days to stop it from bending or becoming damaged as it cooled down.
This slow rotation was done using a system called the Turning Gear, which gently rotated the shaft at about 10 turns per minute. While this was happening, a Turning Gear Oil Pump kept oil flowing to the bearings (the parts that help the shaft spin smoothly) to stop them from wearing out.
There was also a second pump called the Jacking Oil Pump, located at the back of the machine. This smaller pump pushed a little bit of high-pressure oil underneath the shaft while it was still. This helped lift the shaft slightly to reduce friction and prevent damage before it started turning.
Once the shaft began rotating and the main oil system took over, the jacking pump would automatically switch off.
No 6 Alternator Vent Fan and Motor
East side of "B" Station Turbine Basement
This fan and motor unit was built in 1938 by British Thomson-Houston, a well-known electrical engineering company based in Rugby, UK.
It is one of two large fans that helped cool the alternator—the machine that generates electricity—by blowing air through its internal components and across a water-cooled heat exchanger. The cooling water came from the station’s main water system and passed through extra filters (called strainers) before reaching the heat exchanger.
The second fan was installed on the western side of the alternator, near the boiler house extension.
In most cases, just one fan was powerful enough to keep the alternator cool, as long as it was running at 80% or less of its maximum power output.
