One pump fits various applications
Many complex industrial processes now require a wide range of different catalysts, reagents and other auxiliary substances which have to be delivered in precise quantities. In most cases this leads to a whole fleet of different pump systems being set up depending on the medium requirements, with correspondingly high expenditure in terms of maintenance and spares inventory and increased training for service staff.
For a single project, a South African producer of platinum metals was therefore looking for both peristaltic pumps to dose flocculants and progressing cavity pumps for anti-foaming agent, as well as vertical centrifugal pumps to supply water to several stuffing boxes – three quite different conveying technologies each with different operating conditions and know-how requirements for the operators.
As a more cost-effective, and less complex alternative to this NETZSCH Pumps & Systems, instead came up with a solution that only used progressing cavity pumps, enabling a considerably less complicated design of the operation and availability of a central contact in the event of any questions. This simplification is made possible by the characteristics of the conveying principle: irrespective of its consistency or viscosity, the medium is conveyed smoothly inside closed conveying chambers, without any strong shear forces or pulsation, from the inlet to the discharge side. In addition, the uniform volumes of the chambers allow accurate, continuous dosing of the delivery volumes using the speed. This enables an accuracy of between five and three percent to be achieved; small dispensers even achieve one percent.
In the end, these advantages led the metal producer to order a total of 18 progressing cavity pumps of the NEMO® BY type for all three areas of application. Two versions were fitted, involving the larger one providing around 4 m³/h of water at 10 bar for the stuffing boxes, while the smaller one feeds flocculants and anti-foaming agents into the appropriate sections of the process. Both models are equipped with robust stators made of chemical-resistant Nemolast® S45 elastomer and have a dry running protection system and a pressure relief valve to increase operational reliability. Sealing is achieved using elastomer bellow seals with silicon carbide sliding rings. This configuration, which is specially designed for a long service life, has enabled the pumps to operate without any problems and to meter the different auxiliary substances with the required accuracy since they were commissioned in the spring of 2013.