Akzo N.v.

Volker Meywald

Karl Ostertag

Klaus Schneider

A gear pump with reduced power requirement for conveying viscous liquids, especially thermoplastic fiber-forming polymer melts or a viscose spinning liquid, with intermeshed gear wheels rotatably mounted on parallel shafts while encased or circumscribed in a pump housing, i.e. enclosed on either side of the gear wheels and around the periphery thereof with an inlet opening for liquid feed means leading into the meshed point or area where the gear wheels disengage or become unmeshed and with an outlet opening for liquid discharge means leading away from the meshing point or area where the gear wheels engage or become meshed, the liquid thus being conveyed by the gear teeth from the inlet opening on one side of the meshing point around the outer portion of each gear to the outlet opening on the other side of the meshing point. A normal pressure-sealing or backflow-inhibiting radial gap is provided over at least a portion of each gear wheel periphery, i.e. between the top land or crown of the gear teeth and the opposing inner walls of the gear housing, preferably over a distance from the outlet opening of at least about three gear teeth or more. The remaining normally liquid-sealing gap spaces between the gears and the housing are enlarged according to the invention by means of axial recesses in the side faces of the gears and/or in the adjacent internal faces of the gear housing which extend in a plane perpendicular to the gear axes, and/or by means of radial recesses along the inner circular surfaces of the gear housing which extend around a major portion of each gear periphery, each of said recesses being formed circularly or as a sector of a circle, i.e. an arc-shaped recess defined herein as a segmental annulus which in the axial enlargement has the form of a flat annular sector of a circle or which in the radial enlargement has the form of an annular ring segment, and each of said recesses being arranged concentrically to the axis of its associated gear wheel. A gear pump of the invention is especially preferred which has only axial recesses or which has a combination of axial and radial recesses.

Growing community of inventors

Munich, Georgia

Volker Meywald