In-line shut-off valve

An in-line shut-off valve comprising:

• a valve housing having a straight water flow channel therethrough and a cylindrical bore through the valve housing having its axis of symmetry perpendicular to the axis of symmetry of the water flow channel, said water flow channel terminating as two apertures in the wall of said cylindrical bore;
• a valve shaft placed for rotation about its axis of symmetry in said cylindrical bore, said valve shaft having a journal extending along a portion of said shaft and overlapping said apertures in the wall of said bore, said journal having a convex surface of curvature and an elongated concave cavity therein, opposite said convex surface, the cavity being equal in length along said shaft to the length of the journal, water flowing from one aperture to the other around the convex surface in the bore when the valve is open;
• and
• an elongated plug captured by the cavity in said journal, said plug having one side exposed and abutting the wall of said bore, the exposed surface of said plug being of a size to overlap one of the apertures in the wall of the cylindrical bore whereby rotation of said valve shaft causes said plug to slidably engage and seal this aperture.