POSI-SEAL® A31A is a high-performance butterfly valve featuring a keyed shaft for on-off service. A31A is available in NPS 14 through 24, CL150 and CL300. This valve is available in either a flangeless wafer-style design, or a single-flange (lugged) body. The Cryogenic version of this valve is available in NPS 3 through 24.
- Developed as a valve/actuator packing with a double D drive shaft to allow easy, direct mounting to a rack and pinion actuator, eliminating the need for external coupling systems.
- Concentric rotation ensures that the valve disk remains in the closed position, even in the event of line pressure surges or actuator failure.
- The torque necessary to open and close the valve is the same, regardless of the direction in which the differential pressure is applied.
- Interchangeability of all parts, including shafts and disks, simplifies service and reduces maintenance costs.
- Seal retainer screws are located so there is no interference with the sealing function of either flat sheet or spiral-wound line flange gaskets.
- The valve body self-centers on the line flange bolts as a fast, accurate means of centering the valve in the pipeline.