Case study: water utility pump crisis resolved by rapid repair
22 Aug 2016
Engineering services firm completes quick fix for catastrophic pump failure.
Scottish Water is one the UK’s largest water and wastewater utilities and is the sole provider of services to an area that is one third of the size of Great Britain.
Throughout the course of a day, it provides 1.34 billion litres of water to over five million customers. It also collects and treats almost 850 million litres of wastewater, which is returned to the rivers and seas.
The utility also tests samples taken from water treatment works, service reservoirs and customer taps.
Across its sites, Scottish Water has more than 200 Archimedes screw pumps in operation.
Crisis call
At the company’s Alloa sewage treatment works, the site manager was recently faced with the need for a rapid repair to an Archimedes screw pump and its screeded trough, which had suffered a catastrophic failure.
Scottish Water called on the services of ECS Engineering Services, which had recently entered into an agreement with the utility to provide support services for screw pump assets.
ECS Engineering Services was chosen because of its experience in the repair and maintenance of screw pump assets, the company claims.
The damage to the concrete trough meant that the Archimedes pump would have to be lifted out before the task of removing the failed screed and bearing plinths with a remotely operated robotic breaker could be completed
When called to the Alloa site, ECS Engineering Services was able to provide a comprehensive assessment of the damage and the work required to complete the repair in a short timeframe.
The damage to the concrete trough meant that the Archimedes pump would have to be lifted out before the task of removing the failed screed and bearing plinths with a remotely operated robotic breaker could be completed.
This method provides a safe and effective means of breaking up the concrete, allowing it to be removed quickly and preparing the way for a new trough lining to be installed while alleviating many issues relating to hand arm vibration syndrome, ECS Engineering Services says.
Hands-on approach
Once this task had been completed, the engineers could hand-finish the screed to provide the required fit for the screw pump to operate in.
“The fit of the screw in the trough is crucial in determining the overall efficiency of the pump and was managed to a design clearance of 5mm. At the same time, the new stainless steel bottom bearing was installed, finishing the preparation work,” ECS Engineering Services says.
Finally, ECS Engineering Services had to reinstall the Archimedes pump, connecting it to the drive end and installing the lower bearing, which is sealed for life and requires no annual maintenance.
With everything in place, the screw pump was tested and commissioned before being handed back to Scottish Water and put back into normal service, ECS Engineering Services says.
