Plug valve assembly

A plug valve assembly comprising:

• a. a housing having aligned generally cylindrical inlet and outlet ports in the side walls thereof, a cylindrical valve chamber therebetween having its vertical axis normal to the axes of said ports and being closed by end walls;
• b. generally cylindrical valve sealing members slidably mounted in the cylindrical walls of said ports, each said sealing member having a main body portion with a concave end face portion adjacent said valve chamber and an axial bore extending therethrough, said main body portion having an annular recess on the cylindrical surface thereof extending from said concave end to an annular abutment intermediate the length of said main body portion and a generally tubular resilient collar slidably mounted on the recessed portion of said main body, said collar having a thickness substantially equal to the depth of said recess and having a concave end portion protruding beyond the concave end of the main body portion by a distance of about 0.025 to 0.25 mm;
• c. a cylindrical valve member having at least one transverse port therethrough positioned within said chamber with an annular gap of about 0.025 to 0.25 mm between the cylindrical valve member and the cylindrical wall of the valve chamber, said valve member being in resiliently sealing engagement with the concave end portions of the sealing member resilient collars, and resiliently supported for rotation by resilient valve seating and sealing members at the top and bottom regions of said valve member;
• and
• d. means to engage said valve member and rotate same while thus supported.