Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/682797
20 | JUNE 2016 | WWT | www.wwtonline.co.uk Project focus: Pumps and pumping systems bearing temperature monitoring, thermal motor protection and leakage sensor in the motor. They also have a low-vibration hydraulic system and a bellmouth optimised for vortex-free inflow making them an excellent choice for the Renfrew project. Pump discharge rates have been defined as 1253l/s (at 7.8m pumping head), 1560l/s (at 3.3m pumping head) and 1375 l/s (at 6.1m pumping head) under normal conditions. The maximum design flow for the station has been defined as 5500l/s, which is based on four pumps working simultaneously and delivering 1375l/s each. The pumps selected offer the best efficiency over the required operating points. The number and speed of operational pumps is controlled by PLC system, based on the water level in the pump well. Well level is continuously monitored by an ultrasonic sensor and pump operation is determined • Perspectives PJ McFeeley, Contracts Director, Ferrier Pumps: "Ferrier Pumps were delighted to be involved in this challenging project. Particular thanks should be given to the client and their design team, for affording Fer- rier/KSB the opportunity to be involved in the front end design. By utilising our combined skills and experience on projects of a similar nature, we were able to contribute significantly to the MEICA design, thereby avoiding future potential risks during the construction phase." Le : One of the pump canisters being lowered into position. Right: The completed pumping station. individual double flanged sections with a combined weight in excess of 3000 Kgs and an overall assembled length of nearly 10 metres. The top section of each canister incorporates a DN800mm x 180-degree open ended discharge that feeds into the discharge chamber of the pump station from where the flow gravitates away from the Clyde. A"er fabrication the canisters were coated with a fusion bonded epoxy coating. Before any manufacturing of products or site work began, a report covering the testing and development work was undertaken on a physical hydraulic model of the proposed North Renfrew Pumping Station and associated discharge chamber arrangement. The model was constructed to a scale of 1/7th full size and the purpose of the pumping station model study was to investigate and confirm the pumping station hydraulics, the proposed operating philosophy and the self-cleansing characteristics of the initially proposed design. Where required, suitable modifications were developed in each case to optimise each component of the overall arrangement to ensure acceptable operation could be maintained across the required flow and level range and with varying combinations and number of operative KSB pumps. This report proved invaluable in preventing expensive problems at a later date, further into the project. Ferrier Pumps carried out the mechanical and electrical installation for George Leslie Ltd which was the main contractor. The £3.6m project was commissioned by Renfrewshire Council as part of the overall £10m flood prevention scheme for the town. by optimisation of efficiency. When the River Clyde's level begins to rise and the water level reaches the lower limit of the modulating band the first pump will be initiated at minimum speed. If the inflow is less than the pumped outflow at minimum speed, the level in the pumping station will fall and the pump will be stopped at the defined "cut out" level. If the inflow is greater than the minimum pump discharge rate, the level in the wet well will continue to rise a"er the pump starts. The sump water level will now be within the modulating band and the pump controller will modulate the speed of the pump in proportion to the level until the pump can stabilise the level at, or around the set-point level. If the duty pump operates at full speed and the level continues to rise, a second pump will be initiated ramping up from base speed until the inflow can be matched with a level within the modulating band. When there is a heavy rainfall, all four pumps can be called to run depending on the water levels in the main sump tank. Ferrier Pumps also installed in the main sump chamber a KSB Amarex KRT submersible solids-handling centrifugal pump, specifically manufactured in abrasion resistant materials to remove storm water as well as handling a relatively high concentration of solids in the pump station. This variable speed pump is used for sump drain down following cessation of a storm event. KSB have also supplied the pump discharge canisters, which were designed by KSB and manufactured by Powerrun Project Management Ltd of Keighley. Each 800mm diameter canister was supplied to site in three