Gear pump for viscous fluids - has recesses in housing or gears increasing intervening gaps in radial and axial directions

摘要

The gear-type pump has two meshing gears (3). The radial gap (10) between the gears and the pump housing (2), and/or the axial gap between gears and housing, are increased by internal recesses (8, 9) in the pump housing or in the sides of the gears. The recesses are circular, or form segments of a circle, and are pref. concentric to the gear spindles. The depth of the recesses, measured in the radial or axial direction as the case may be, can be between 40 and 60 microns. In the axial direction the gap in the widened part can be up to 15 times that in the non-widened part.