| 摘要 |
An improved rotary plug valve which has a housing having an axial, tapered inner wall forming a tapered inner cavity, with a plurality of radial openings in a transverse plane, at selected angles, leading into the tapered inner cavity. A rotatable tapered plug is adapted to fit inside the tapered cavity, and having "0" ring seal means to seal the outer surface of the plug to the inner wall of the housing. Selected conduits through the plug provide means to control flow of liquid entering one or more of the openings in the housing, to flow through the plug to other selected openings, dependent on the anular position of the plug. The cavity is closed by top and bottom closures. The rotor has an axial shaft, by means of which it can be rotated exteriorly of the valve, by the passage of the shaft up through the center of the top closure. There are cooperating cam surfaces on the top of the plug and the bottom surface of the top closure, and similarly, between the bottom surface of the plug and the top of the bottom closure, such that, as the plug is rotated in one operating position, it is at its lowest position in the tapered cavity, with the surfaces fully sealed, whereas, as it is turned the plug is lifted by the cooperating cam surfaces below, so that there is more clearance between the plug and the tapered inner surface and the rotor can be turned freely.
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