Plug-valve having a plug assembly with retractible seals that can be removed without leakage

A plug assembly for a retractable seal-reseating element non-lubricated double block and bleed plug valve;

• the valve having an inlet and an outlet integral to a valve body and an operator for selectively orienting the plug within the valve body to either align a waterway with the inlet and outlet to open the valve or align the waterway substantially perpendicular to the inlet and outlet to close the valve;
• the assembly comprising:
• a tapered, faceted, cylindrical plug having said waterway therethrough;
• a pair of shut-off slips positioned on said plug for relative axial movement therebetween, the plug surfaces adjacent said shut-off slips being tapered for radially retracting said shut-off slips as said plug is moved axially in a first direction relative to said inlet and outlet;
• a pair of thru-bore slips positioned on said plug adjacent said waterway for relative axial movement therebetween, the plug surfaces adjacent said thru-bore slips being tapered for radially retracting said thru-bore slips as said plug is moved axially in a second direction relative to said inlet and outlet;
• said thru-bore slips each having a thru-bore aperture to permit flow through said waterway without leakage around said plug when said waterway is aligned with said inlet and outlet;
• and
• a trunnion attached to said operator for rotating and translating said plug, said shut-off slips and said thru-bore slips within said valve body.