The Cryogenic Cam Butterfly Valve (CCBV) is designed so that the disc rides on a cam shaft and is held rigid by a torsion spring, which provides both axial movement of the disc in addition to the standard 90 degree rotation of a standard butterfly valve. Because the valve’s disc can rotate and translate, it can hold a tighter seal, preventing leakage despite dimensional changes caused by changing operating temperatures.
The novel Cryogenic Cam Butterfly Valve(CCBV) design, functions like a typical butterfly valve: the handwheel is rotated to open or close the valve. The CCBV has a preloaded torsion spring mounted concentrically on the shaft with the spring legs against the disc, and a pin to keep the disc coupled to the shaft. The torsion spring is preloaded with sufficient torque so that the disc/shaft assembly acts like the disc is rigidly pinned to the shaft. All actuator and shaft rotation beyond 90 degrees translates the disc towards the body seat to create a tighter seal, similar to how a globe valve functions.