Performance guarantees

Performance guarantees for grinding and separation processes in theory and practice

1 Messung von Talkproben unterschiedlicher Lamellarität mit Lasergranulometrie und Sedimentationsanalyse im Vergleich • Measurement of talc samples with different lamellar structure with laser granulometry and sedimentation analysis in comparison

2 Relevante Parameter am Sichtkorb • Relevant parameters at the separator cage

3 Ermittlung vom Intex T in Abhängigkeit vom vom Korbdurchmesser sowie von der Umfangsgeschwindigkeit • Determination of the Index T as a function of the cage diameter and the circumferential speed

4 Beurteilung der Trennschärfe eines Sichters über Kennwerte der Teilungskurve nach Tromp • Assessment of the separation sharpness of a separator based on characteristic values of the Tromp partition curve

5 Spezifischer Energieverbrauch • Specific energy consumption

6 Darstellung im doppelt logarithmischen Maßstab • Shown as double logarithmic plot

Standort der PMT-Jetmill GmbH in Kammern/Österreich • Site of PMT-Jetmill GmbH in Kammern/Austria

Summary: Performance guarantees are usually agreed for both new plants and the conversion of existing plants and equipment. Unfortunately, these are increasingly becoming a plaything in business, on the part of the suppliers to secure orders on the strength of such guarantees and on the part of the customers hoping to keep the liability escrow on conclusion of a project. Sometimes demands are made for multiple performance guarantees, which are then mutually exclusive. This paper – according to a lecture presented at the Mineral Processing Seminar 2014 at Montan University of Leoben/Austria, from 30.–31.01.2014 – is intended to explain some relationships common in grinding and separation, on the basis of which performance guarantees can be specified.

1 Basic considerations

Warranty agreements are regulated on the basis of statutory provisions, in Austria, for example, the Austrian Civil Code (ABGB). The legislator stipulates that a party who delivers goods or services to another party in return for payment guarantees that these correspond to those specified in the contract. The former party is therefore liable that the goods or services exhibit the stipulated or usually assumed properties, that they correspond to a description, or sample or model and they can be used according to the nature of the business transaction or any arrangements...