Study on performance of progressing cavity pumps (PCPs) in different fit modes

Abstract

The performance of progressing cavity pumps（PCPs）is significantly different in different fit modes between the stators and rotors，such as interference fit for conventional PCPs with rubber stators and clearance fit for novel all metal PCPs. In order to study the influence of fit modes on PCP performance, a novel concept of fit parameter is introduced to quantitatively describe the fit condition. Based on working principles of PCPs, comprehensive studies are carried out on pump performance in different fit modes, including volumetric characteristics, power consumption and work efficiency. The results show that the theoretical pump rate slightly decreases with the increase of the fit parameter. Though there is obvious friction inside the pump and the interference has a great impact on power consumption, the PCP in interference fit is able to achieve high volumetric efficiency (>80%). Though there is inevitable leakage and the clearance has a significant influence on flow rate, the PCP in clearance fit can reach high mechanical efficiency (>90%). The novel all metal PCP in clearance fit has enormous potential for development owing to its good overall performance.