Eccentric, rotary plug valve

Eccentric, rotary plug valve comprising:

• a. a housing capable of being suitably connected to a piping system and having a co-axial inlet port and an outlet port connected by an enlarged inner cavity, said housing further having a hollow bonnet extension extending perpendicularly from the axis aligning said inlet and outlet ports;
• b. an annular seat ring having a circular bore and being suitably fastened within said housing cavity and near said inlet port whose one terminating end has a chamfered seating surface;
• c. a plug adjustably connected to a hub element, the latter having an upper and a lower portion where the lower portion has a pierced opening constituting a shaft passageway whose axis being offset from that of the annular seat ring, said plug having a semi-spherical front face whose spherical radius sealingly engages the seating surface of the seat ring and a flat rear face having a lower and upper portion and a centrally attached stud with a threaded rear portion connecting with a similarly threaded opening within said hub element and capable of adjustably moving said plug towards or away from said seat ring and into a correct geometric relationship with said seat ring when the plug is sealingly engaged with said seat ring, said hub element having a lower portion having a surface complementing that of the rear face of the plug and configured to cover at least one half of the lower rear face and less than one third of the upper rear face of said plug and being separated from said plug surface by no more than fifteen percent of the diameter of the circular seat ring bore to effectively prevent fluid pressure established near the outlet port and within the housing cavity from affecting the lower portion of the rear face of said valve plug when the latter is not sealingly engaging said seat ring;
• d. a shaft rotably mounted within said hollow bonnet extension and further extending into the pierced opening of said hub element and capable of rotating said hub element together with the adjustably attached plug towards said seat ring in order to affect the a sealing engagement with the latter.