Roger Willis reveals how a Brazilian mining group switched to multi screw pumps

Historically, a Brazilian mining group used multi screw pumps from different manufacturers for the pumping of oil to lubricate and form the journal bearing of ball mills. As contamination of the oil was frequently detected, the pumps had to be replaced regularly. Due to the lack of on-site services of the manufacturers, replacement or spare parts for the imported units were met with long delivery times as well as high costs.

To resolve this issue, the mining company decided to switch to the locally manufactured and supported Notos pumps from Netzsch do Brasil in Pomerode. This company is part of the global Netzsch Pumps & Systems organisation, headquartered in Germany. A deciding factor for this choice was that the mining group would be able to use the service of the Brazilian production plant.

“The multi screw pumps are used to pump oil for the bearings of ball mills. In this application, the oil both lubricates and carries the load of the shaft,” says Monica Mitterstein from Netzsch do Brasil. The customer used two multi screw pumps per mill: up to June 2018, one model pumped mineral oil with a viscosity of 200 cSt at a maximum flow rate of 500 l/min and a pressure of 70 bar. The three additional units pumped ISO VG 220 oil up to 220 cSt. The flow rates were a maximum of 500 l/min at 25 bar, 400 l/min at 80 bar or 144 l/min at 80 bar.

Due to the high contamination of the oil, the original eight pumps had to be replaced every six months. As the customer used a large number of pumps, which were imported, the procurement of new pumps and spare parts was costly, had long delivery times and required additional stock for emergencies. “The switch to Notos pumps happened very quickly and was motivated by the desire to simplify spare part procurement, lower the spare part costs and have service engineers available on-site”, explains Mitterstein. “Furthermore, the new pumps were expected to be more reliable than the previous models.”

Benefits of switching multi screw pump manufacturers

For three of the four pumps used in Brazil, Netzsch only provided the cartridge, as the housings of the original pumps could still be used with no problems. This resulted in various benefits for the customer. On one hand, the costs for installation remained low; and on the other, three completely new and efficient Notos pumps are now available in the process. Netzsch only supplied the complete unit for the fourth model as the cartridge did not fit into the housing of the original pump.

“Also, the fourth model 3NS works with no problems and meets all the customer’s requirements,” adds Mitterstein.