| 摘要 |
A plug valve adapted to meter precise quantities of material passing therethrough in which a cylindrical valve plug is rotatably mounted in a cylindrically shaped aperture in a valve body. First and second sets of radially extending inlet and outlet passageways are connected to the valve body aperture, with each inlet passageway being radially opposite a corresponding outlet passageway. Two orthogonally oriented, nonintersecting valve ports extend through the valve plug perpendicular to its axis of rotation, the ports being closely spaced from each other along the axis and with the diameter of each valve port being approximately one-half the diameter of the passageways such that one valve port connects one set of inlet and outlet passageways while the orthogonally positioned second port simultaneously connects the second set of inlet and outlet passageways. One inlet passageway connects to a source of material to be metered, and fills one of the valve ports with a precise volume of the material, the associated outlet passageway of that set of passageways being normally closed to prevent the egress of material therefrom. Rotation of the valve plug aligns the filled valve port with the second set of passageways so as to allow the quantity of metered material to flow from the valve. As one valve port is being filled with a metered quantity of material, the second valve port is being emptied of material simultaneously therewith.
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