Coker switch valve operating system and method

An operating system for selectively rotating a valve stem of a coker switch valve between alignment positions for the valve to direct a stream of heavy oil to a first coke drum, a second coke drum, and a bypass, comprising:

• an actuator releasably engaging a stem adaptor for rotation about a central axis of the valve stem;
• a shear pin linkage between the stem adaptor and a locking plate to rotate the locking plate in response to rotation of the stem adaptor by the actuator;
• the locking plate releasably engaging the valve stem to rotate the valve stem in response to rotation of the locking plate;
• a mounting flange spool having a lower flange fixedly attached to a bonnet of the valve and an upper flange;
• diametrically opposing first and second lobes formed on the locking plate and extending outwardly into an annular track adjacent the upper flange as a path of rotation of the lobes about the axis;
• a plurality of locking pins releasably securable to the upper flange at a like plurality of stop positions and extendable into the annular track to limit movement of the lobes in the annular track, thereby limiting rotation of the valve stem;
• wherein, when the valve is in the alignment position for the first or second coke drum, disengagement of first and second ones of the locking pins from respective first and second stop positions and engagement of a third one of the locking pins allows rotation of the valve stem between the first and second coke drum alignment positions of the valve and prevents the valve stem of the valve from rotating to the bypass alignment position of the valve;
• and
• wherein, when the valve is in the bypass alignment position, engagement of the first and second ones of the locking pins in the first and second stop positions, respectively, prevents rotation of the valve stem of the valve out of the bypass alignment position of the value.