Bearing-less positive displacement flowmeter

Claim 1

A fluid metering apparatus comprising, a chamber comprising an oblated chamber having two opposed radiused portions separated by two opposed linear portions and first and second flat end plates connected to opposite end faces of the oblated chamber, a fluid inlet disposed in one of the two opposed linear portions of the oblated chamber, a fluid outlet disposed in the other of the two linear portions of the oblated chamber, the inlet and outlet having an axis bisecting the chamber, two non-metallic intermeshing rotors, each having a plurality of singly radiused lobes equidistantly spaced apart by singly radiused nadirs, rotatably mounted within the chamber in intermeshed relationship between the first and second flat plates, the rotors having overall radii corresponding to the radiused portions of the oblated chamber and the radiused lobes being in the radiused portion of the oblated chamber, and intermeshing at a point near a center of the chamber, whereby fluid entering the chamber through the inlet causes the lobes of corresponding rotors to move in a rotary direction, marker means, disposed in each of the plurality of lobes, and single pickup and indicating means, on a plate in the center of the chamber adjacent the marker means, and responsive to the marker means in both rotors for picking up passage of the markers and for indicating a quantity of electrical signals for both lobe means, the quantity being determined proportionate to rotational speed of the two rotors, said chamber acting as a guide for said rotors and restricting each to rotary movement.