Fig.272 is designed with a pneumatically inflatable resilient seat intended for abrasive and high-cycle service. During opening and modulation, the sealing element remains depressurized, maintaining a controlled clearance between disc and seat and significantly reducing seat-to-disc contact during cycling.

At the closed position, compressed air is introduced into the elastomeric sealing ring, causing radial expansion and generating uniform circumferential sealing pressure. By separating the dynamic movement from the sealing function, wear is minimized and long-term shut-off reliability is enhanced.

The valve is particularly suitable for powders, granulates, irregular solids, gases and slurry applications where conventional resilient-seated butterfly valves are subject to accelerated wear.