Velan's proven pressure seal design. No penetration of hinge pin to outside eliminating possibility of pin seal leakage and allowing for in-line service. Compact cage unit: all moving parts are attached to the carrier and can be removed easily for service. Forged seat/disc is CoCr alloy, ground and lapped to a mirror finish for maximum erosion resistance and long service life. It is seal-welded to the body. Disc can partially rotate for tight shutoff. In the fully open position, it rests against a stop. CoCr alloy bearings for hinge pin. Easy in-line service. All parts are easily accessible for maintenance. Seating faces can be re-lapped. Forged bonnet.