For a reservoir project in Wales, Glenfield Invicta’s team of experts rise to the challenge to find the most optimal valve and flow control solution
Lewis Civil Engineering, based in Pontyclun, South Wales, is leading a refurbishment project at Alwen Reservoir for Dwr Cymru Welsh Water (DCWW). A vital element of the enabling works was the creation of a duplicate water supply arrangement as the existing mains were to be shut off whilst work was being carried out on the reservoir.
How to choose the optimal valve?
Lewis Civil Engineering contacted Glenfield Invicta for advice on the best valve to use for the temporary supply pipeline. An over-pump arrangement at the dam's top connected to an existing supply pipeline 30 metres below the reservoir level for temporary supply. DCWW's operational parameters were demanding: a maximum pressure of 25 m to enter the existing works, as well as the ability to achieve a range of flow rates up to 462 litres/second.
The natural choice for this application would have been a pressure reducing valve. However, due to the small differential pressure requirement of 5 m, the pressure reducing valve (PRV) would have been working close to its limit. Because it was critical that pressures greater than 25 m not be introduced into the existing infrastructure, an alternative control valve solution was required.
Demonstrating engineering expertise
The Glenfield Invicta engineering team therefore considered whether a series 75 concentric butterfly valve would meet the operating criteria. To accommodate the range of specified flow requirements at the available pressures, a series 75 concentric butterfly valve (DN450) would be operating within a range of 35% and 45% open position. This is well within the valve's allowable limits. As a result, the series 75 concentric butterfly valve was installed.