To reduce the leakage losses, the ring gear of an internal gear pump is pressed against the internal gear and a sickle-shaped body is placed between the ring gear and internal gear, minimising the play of the cog tips, depending on the pressure (Figure R 1). The radial gap compensation makes a significant contribution to allowing such internal gear pumps to work at pressures of 300 to 350 bar.
Figure R 1: Radial gap compensation