Leakage Detection Butterfly Valve

How does the Leakage Detection Butterfly valve work 

With its double block-and-bleed design, the Alfa Laval Leakage Detection Butterfly Valve ensures the separation of two products. In closed position, the valve disc creates two sealing points with an intermediate space between them. This space forms a leakage chamber at atmospheric pressure under every operating condition. If leakage occurs, the product flows into the drain through the outlet connections at the bottom of the valve for easy detection. When the valve is open, the leakage chamber is closed, and the product flows from one line to the other.

The valve can be operated either by a pneumatic actuator from a remote location or manually using a handle. The actuator comes in three standard versions: normally closed (NC); normally open (NO); and air/air activated (A/A). For pneumatic operation, an actuator converts axial piston motion into a 90° rotation of the shaft. The actuator torque increases as the valve disc meets the valve seal ring to secure the proper closing of the valve seat. For manual operation, a handle mechanically locks the valve in an open or closed position. Manual valves can also be mounted with indication units for feedback on the valve position (open/closed).