Problems relating to high-pressure gear micropumps

•A survey of typical micropumps is carried out.•Micropumps designed in-house, with a delivery of 0.8 cm3/rev. and 1 cm3/rev., are presented.•A special test rig was designed and built for determining the characteristics of pumps.•Some of the test results are reported.

This paper presents the current development trend in high-pressure hydraulic micropumps. A survey of typical micropumps is carried out. Micropumps designed in-house, with a delivery of 0.8 cm3/rev. and 1 cm3/rev., are presented. A special test rig was designed and built for determining the characteristics of pumps. Some of the test results are reported. They indicate the necessity for further research in this area, particularly into the encountered efficiency problems.