Hermetically Sealed Rotary Bellows for Reducing Stem Seal Leak Rates

The proposed innovation is a hermetically sealed, additively manufactured torque transmission device suitable for use in cryogenic and high-flow valve applications.nbsp; The innovation consists of a series of additively manufactured pleats oriented axially, allowing relative rotational motion between the actuated shaft and the valve body. This rotary bellows is hermetically sealed to the valve body.nbsp;nbsp;nbsp;For the baseline design, the valve stem interfaces with a slip-fit shaft coupler integral with the end of the rotary bellows and the bellows is hermetically sealed to the valve body on the opposite end. The actuation shaft is driven from above, twisting the flexible bellows and actuating the valve ball.nbsp; The design is adaptable to nearly any 45 or 90-degree rotary operated valve with a stem adapter and static seal at the valve body/bellows interface. The design is also fully compatible with vented balls and vented seats for use with cryogenic liquids. The rotary bellows also functions as a torsional spring which eliminates the need for a separate spring in the actuator in order to yield valve that passively closes when de-energized.