Ebro's Inflatable Seat INFLAS is a sealing system for very sensitive or highly abrasive media. It's available for all resilient-seated butterfly valves with interchangeable seat. In its closed position, the liner will be pressed against the disc using low air pressure.The media is sealed off securely. Before opening the disc, the chamber is vented behind the liner. This creates an air gap between the liner and the disc, so it requires less torque to open the valve.