Gear Pump Performance Shortfall Analysis Case Study

Problem

A polymers production plant was experiencing a severe shortage of throughput of a polymers double gear pump. KHE was contracted to determine the cause of the shortage and to determine what changes were needed to increase the throughput to acceptable levels.

Solution

KHE performed a general assessment of the pump design and operating conditions. We also collected field data from dynamic pressure transducers mounted on both the inlet and discharge transition pieces as well as the inlet and discharge pump chambers. KHE also performed leakage calculations based on the clearance tolerances and a Computational Fluid Dynamic analysis of the suction chamber and compression zone of the pump. It was determined that leakage due to clearance tolerances was higher than originally specified by the pump manufacturer. KHE found that the performance loss was mainly caused by incomplete fill of the gear teeth due to inappropriate design geometry of the compression zone. KHE worked with the OEM to redesign the compression zone geometry using CFD methods to evaluate the performance of design changes.

Results

A new design of the compression zone resulted in an improvement of the pump performance that met the designed minimum requirements for throughput. In addition, shims were added to reduce the leakage caused by clearance issues.