Cryogenic Butt-weld Two Pieces Ball Valve

Cryogenic Butt-weld Two Pieces Ball Valve

A floating ball valve is a valve with its ball floating (not fixed by a trunnion) inside the valve body, it drifts toward to the downstream side and tightly pushes against the seat under the medium pressure to ensure sealing reliability. The floating ball valve has simple structure, good sealing performance but the seat material is required to withstand the workload since the sealing pressure is bared by the seat ring. Due to unavailability of high performance seat material, floating ball valve is mainly used in middle or low pressure application.

Design FeaturesReliable Seat Seal
The structure design of double-beveled sealing ring has been adopted to reduce the friction between the ball and the sealing ring to achieve lower operation torque.  When the medium pressure is low, the ball has smaller contacting surface with sealing ring, which introduces higher sealing pressure to ensure the sealing reliability. When the medium pressure gets higher, the contacting area between ball and sealing ring increases accordingly. Larger contact area reduces the sealing pressure to avoid the deformation of sealing ring.

Fire Safe Design
In case of fire, non-fireproof material for packing and seat will be burnt-out and considerable medium leakage may possibly cause fire spread. CRV adopted metal to metal seal as auxiliary structure to prevent medium leakage in case of fire as shown in figures. The fire safe design confirms to the requirements of API607, API 6FA and BS 6755.