US Patent 10378656 Valve with active seal and shaft blowout prevention device

A valve includes: a valve body defining a shaft bore therethrough, the shaft bore defining an axis extending through the valve body; a valve shaft positioned within and configured to rotate within the shaft bore of the valve body, the valve shaft including a shaft shoulder defining a shaft shoulder surface facing upward; a top cap secured to the valve body, the top cap including a bore shoulder defining a bore shoulder surface facing downward, the bore shoulder surface facing the shaft shoulder surface; and a seal positioned between the top cap and the valve body, the seal configured to seal against leakage from between the valve body and the valve shaft.