The Jacques Avias pumping station at the karst spring of the French river Lez southeast of Les Matelles supplies the entire Montpelliers community with fresh drinking water. Since 1982, tandem submersible motor pumps from the German pump manufacturer Pleuger Industries have been pumping 1700 litres of drinking water per second from three well shafts to the surface. A fourth pump discharges 250 litres of water per second into the Lez, which is one of Europe’s “Natura 2000” protected areas and is home to unique animal species such as the Petit Groppe. After 30 years of operation, the Montpellier Water Board commissioned Pleuger Industries to replace two pumps that had reached the end of their maintenance cycle.
The pumping station at Les Sources du Lez was equipped by Pleuger at the beginning of the 1980s with two-stage submersible motor pumps – specially dimensioned for the application and designed for trouble-free operation for 30 years. It is the only source from which the people of the metropolitan region receive their water. Only a routine maintenance after 15 years planned by the water protection authority “La Régie des Eaux” was to interrupt the operation of the machines at short notice. After 30 years, two of the 20-ton and 10-metre-long twin units were replaced in accord-ance with the regulations. Pleuger Industries was again awarded the contract for the project because, on the one hand, the uniformity of the original functional group was to be maintained and, on the other hand, the Pleuger brand was to ensure maximum reliability due to years of cooperation.
The new 32-inch centrifugal pumps are two-stage special designs of type QN362-1a + VNI22-150-6-6: The 590 kW water-cooled stainless steel motor with a power output is located below the hydraulics and supplies spring water from the underground cavern via a suction-pressure jacket. The drinking water flows through a single-stage grey cast iron pump hydraulic system into the connected pressure boosting system of the same type, which transports 3500 m³/h of drinking water 36 metres upwards. The motor is operated via a frequency controller with a rated current of 1020 A.
“Since the investment in the Pleuger pumps pays for itself after just 15 years, but they are designed to last twice as long, we can guarantee a cost-covering and trouble-free water supply for the entire Montpellier metropolitan region,” emphasizes Adelaide Kasolter of the Montpellier water authority “Régie des eaux”, who travelled with her colleagues and the French customer advisors from France to the Pleuger production site in Hamburg to accept the motor pump unit ordered. “As our analyses have shown, our Pleuger pumps theoretically last more than 30 years, but in the public water supply of more than 400,000 citizens, operational safety is the top priority. Here we focus on preventive renewal.”