Roto-Disc Inc. (Erlanger, KY) has completed the design of an Inflatable Seal Mechanical Interlock system for the Roto-Flate spherical valve that enhances its reliability and causes it to fail closed and inflated in the case of electric or pneumatic loss. The Mechanical Interlock prevents the inflatable seal from inflating before the valve dome is in the closed position. When utilized with a spring return pneumatic actuator and normally open seal solenoid, the Roto-Flate now closes AND inflates upon electrical power loss, regardless of the position of the valve at the time power is lost. Among other benefits:
- The interlock prevents un-intended and/or premature inflation of the inflatable seal, thereby decreasing risk of damage during start-up.
- For applications where the valve is required to also close on pneumatic loss, the Roto-Flate can be provided with a valve arrangement that will inflate the seal from a reserve air-source, and keep it inflated for extended periods.
- Applications that require a fail-open or fail-last disposition can also be easily accommodated upon request.
These enhancements allow users of the Roto-Flate to gain the benefits of its 2-stage sealing system while being assured of a known action in the event of electric of pneumatic loss.