Features:
1) Handwheel torque or actuator force provides positive seat-knife closure
2) During closure, the stem slides down pushing the knife into contact with the two bottom lugs
3) The taper stem head then transfers a vertical closing force to a lateral force which positively seats the knife against the seat face
4) Stem force, not line pressure, maintains seating contact in this unique design, ensuring tight seating in both directions
5) During the opening and closing cycle, the guides ensure proper alignment of the knife.