A modern approach to a vintage problem

Flow discovered how electromechanical repair specialist Mawdsleys used its expertise and state-of-the-art technology to ensure a 90-year old heritage asset could continue serving its local community.

The Cirencester Open Swimming Pool is far more than a local amenity; it is a piece of living history. Opened in 1870, the pool is a community-run charity that has served the Cotswolds for over 150 years. Today, it remains a bustling summer destination, welcoming up to 500 visitors a day and 1,500 swimmers per week during its peak season from April to September.

At the heart of the pool’s circulation, a Bell Brothers filter system and its accompanying pump and motor date back to 1935. For the team at the pool, this machinery represents a standard of quality that is increasingly rare. Their shared philosophy is one of sustainability and respect for legacy craftsmanship. In an era of throwaway plastic components that often fail within five years, the pool team’s goal was clear: preserve this 90-year-old industrial workhorse to ensure the charity can continue to provide for the community for another 20 years.

The challenge

Recently, as the 1935 split-case pump and motor were facing the inevitable toll of nine decades of service, the facility faced several critical issues.

The pool operates with a single circulating pump. There is no backup. If the pump fails during the five-month season, the pool must shut down immediately, resulting in a total loss of community service and vital charity income.

The system was pulling air through blown seals, and the motor was frequently tripping out upon startup, suggesting deep-seated electrical faults.

All fasteners and components were based on old-style imperial sizing. Finding off-the-shelf parts for 1930s Bell Brothers equipment is a mechanical impossibility.

The solution​

The pool’s team contacted Mawdsleys due to the company’s multidisciplinary expertise. With a long history of motor engineering excellence and specialist pump services, the company was ideally placed to help.

The project began with a comprehensive on-site consultation to bridge the gap between the 1930s installation and modern requirements. Mawdsley’s engineers conducted a thorough physical assessment of the Bell Brothers system, identifying not only the failing seals and electrical trips but also the complexities of the surrounding imperial-sized pipework and infrastructure.

Mawdsleys Pump Services engineers navigated the complexities of the 90-year-old imperial bolts to safely extract the massive split-case pump and motor. Once retrieved, the equipment was transported to the company’s workshop.
Inside the workshop, Mawdsleys BER’s motor specialists performed a complete overhaul. Upon dismantling, the windings were found to be unserviceable. The company’s specialists performed a full stator rewind, followed by a steam and stove process to ensure insulation integrity. The bearings were replaced with high-performance RMS10 and MRJ1 3/8 rollers, and the motor was dynamically run to ensure it met modern performance standards.

The pump repair

The split-case pump was stripped to the drive shaft by the Pump Services team. Both pack gland seatings were reclaimed, and the drive shaft assembly was balanced to eliminate vibration. To ensure a perfect seal, a specialised graphite-rope pack gland and custom-cut 0.5 statite paper gaskets were utilised.

The most significant hurdle in the pump repair was the failed lantern rings and worn impeller neck rings. With no replacements available, one of the Mawdsleys BER engineers took a modern approach to this vintage problem. The worn components were hand-measured, and bespoke replacements were manufactured from high-grade nylon using 3D printing. This material deforms slightly under pressure, making it excellent for sealing while providing low resistance due to its naturally lubricious properties.
By insourcing the manufacturing via 3D printing, external lead times were eliminated, and a custom-engineered solution that was literally ‘made to measure’ for the 1935 housing was provided.

After mechanical checks on all the journals and housings confirmed they were within tolerance, both units were professionally re-sprayed in Mawdsleys’ signature protective finish, returning them to the site in better-than-new condition.

The results

The project culminated in the return of the equipment by Mawdsleys Pump Services’ team. The reinstallation was so precise that the original shims were no longer necessary; the pump and motor aligned perfectly with the pedestal on the first attempt.

By acting rapidly and manufacturing their own parts, Mawdsleys prevented a total pool closure.

The motor now draws a steady 3.57A, well within its limits, and the 3D-printed nylon parts provide a seal superior to the original 1950s-era components.

Importantly, a high-quality heritage asset was saved from the scrap heap, satisfying the client’s desire to avoid disposable modern alternatives.

And the client received a bespoke, modernised pump system for a fraction of the cost of re-piping the plant room for a new unit.

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