Decanter centrifuge

US4298162A · kind A · utility

Assignee

• Alfa Laval Separation A/S · SE

Inventor

• Per Hohne · Copenhagen, DK

Key dates

• Filing date: Jan 25, 1980
• Grant date: Nov 3, 1981
• Expiry date: Jan 25, 2000

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B04B1/2016
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A system for controlling the relative rpm. of the conveyor screw of a decanter centrifuge includes a gear interconnecting the screw and the centrifuge drum. The gear has an input shaft the rpm. of which determines the relative rpm. of the screw, and a housing rotating in synchronism with the drum. The input shaft and the housing are coupled to one each of two rotary, positive displacement machines one of which is a constant displacement machine while the other is a variable displacement machine. The machines are hydraulically connected in series in a closed circuit so that a change in the displacement volume of the variable machine, at constant rpm. of the gear housing, results in a change in the rpm. of the input shaft. The variable displacement machine may be mechanically coupled to a further constant displacement machine whereby the flow rate through the variable displacement machine is reduced to the difference between the flow rates through the other two machines.