Rotary plug valve

Claim 1

A rotary plug valve comprising: a valve body having an opening from which radially extend alined flow ports, said opening having an inwardly projecting perimetral flange at one end, an inner annular shoulder intermediate its ends and a tubular nut screw-threaded into its other end, a plastic sleeve compressed into fluid-tight contact with the wall of said opening between said shoulder and said nut and having port holes each in register with one of said flow ports, and a plug extending through said sleeve and said tubular nut in rotatable frictional contact with the inner surface of said sleeve and the inner surface of said nut and the wall of the opening between said inwardly projecting flange and the adjacent end of said sleeve, said plug having a shoulder abutting the underside of said inwardly projecting flange, said plug also having its ends exposed at the ends of said opening and having a transverse passage therethrough selectively movable into and out of register with said flow ports upon rotation of said plug, and a knob mounted on the end of said plug outwardly of said flange in abuttable relation to said body and having a coaxial hole therethrough and a headed screw with its shank passing loosely through said hole and screwed into said plug and its head abutting said knob, with the addition of a stop element adjustably settable in different positions on the valve body beneath said knob and a stop stud on the underside of said knob coactive with said stop element providing for stopping rotation of said plug selectively in any one of a plurality of different positions, said stop element being arcuate and rotatably adjustable on said body coaxially with said knob, and said stop stud being on the bottom side of said knob between and to coact with the ends of said arcuate stop element.