Abstract: There is a gear rotor for use in a positive displacement flowmeter of the type described. The rotor has an external wall profile 8 forming three equally spaced lobes 9 and a partially open core structure inside said profile with internal cavities 15, 15A defined between webs 13, 14 extending from a central hub 12 of said rotor to said wall profile 8.

Abstract: There is a positive displacement flowmeter, which includes at least two primary measuring elements rotatable on respective spaced apart axes within a housing between a fluid inlet and a fluid outlet. The elements are linked to rotate in accordance with volumetric flow through the flowmeter from said inlet to said outlet. There are at least two opposed pole magnets disposed at separated positions on one of the elements and a pole sensitive sensor located in a rotational path of said magnets whereby said sensor is adapted to emit an output signal upon activation by said at least two of said opposed pole magnets.

Abstract: There is a positive displacement flowmeter, which includes at least two primary measuring elements rotatable on respective spaced apart axes within a housing between a fluid inlet and a fluid outlet. The elements are linked to rotate in accordance with volumetric flow through the flowmeter from said inlet to said outlet. There are at least two opposed pole magnets disposed at separated positions on one of the elements and a pole sensitive sensor located in a rotational path of said magnets whereby said sensor is adapted to emit an output signal upon activation by said at least two of said opposed pole magnets.