Oval gear flowmeter for small nominal diameters

摘要

The present invention relates to a small nominal diameter oval gear flowmeter having curved swivel surfaces for automatic self-alignment of the oval gears about a longitudinal shaft axis to enhance measurement accuracy and facilitate restriction-free rotational movement of the oval gears by reducing gaps in the seal surfaces to prevent contact between the oval gears and the axial measuring chamber wall. Two or more oval gears are each supported on independent shafts which in turn are supported in the measuring insert of the housing. The oval gears are supported on the shafts in such a manner that they may swivel at a small angle about the longitudinal shaft axis and that small axial displacements of the oval gears may be accommodated on the shafts. A plurality of recesses that reduce the support length to approximately the shaft diameter are located on both sides of the frontal surfaces of the oval gears, to provide for automatic alignment of the oval gears. In accordance with an alternate embodiment, curved surfaces are provided either on the shafts disposed through the longitudinal bore of one or more oval gears or on the surface of the longitudinal bore of one or more oval gears, thus allowing a small swiveling action about the longitudinal axis of one or more shafts.