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St. Gallen Regional Water Supply Co.: Increase in efficiency thanks to DEPAC mechanical seals

The secure and carefree supply of the 150,000 inhabitants of the St. Gallen region is the core competence of the RWSG. To this end the treated water from Lake Constance is pumped via a pressure pipeline to the city of St. Gallen, some 330 metres higher.

The RWSG uses high-pressure pumps made by KSB for this. These pumps require 1.2 MW of electric power per pump. In order to keep the energy costs as low as possible, pumping takes place overnight during the low-tariff period.

The Frasnacht lake waterworks provides drinking water to the St. Gallen public services companies and others via various pumping stations. The city's transport network is around 246 kilometres long and extends over an altitude range of 400 metres. More than 8.5 million cubic metres of water are transported annually.

Use of mechanical seals reduces energy costs

In the delivery condition the pump shafts had been sealed by the manufacturer with conventional gland packings. This technology is no longer up to date for such demanding applications. In cooperation with DEPAC the sealing systems were given an upgrade - from gland packings to modern mechanical seals. This resulted in a significant increase in the "Mean Time Between Failures" (MTBF).

The conversion of the high-pressure pumps from gland packings to mechanical seals by DEPAC resulted in the saving of part of the annual energy costs.