Fisher® POSI-SEAL® A81
POSI-SEAL® A81 rotary valve with FieldQ® rack-and-pinion actuator offers automated on-off, quarter-turn performance. It is available in spring-return and double-acting piston designs.
Features and Benefits:
Quarter-turn performance— The valve has a square shaft-to-actuator connection and offers automated on-off, quarter-turn performance.
Global Standards— The valve meets API, ASME, and EN standards, making it suitable for use in all world areas. An optional mounting bracket provides ISO 5211 actuator mounting capability.
PEEK/PTFE bearing as standard— The PTFE-lined PEEK bearing is a patented low friction, low wear bearing. It allows the valve to operate under high pressure drops for a high cycle life while maintaining low torque. The "drop-in" bearing design enables fast, easy maintenance.Improved shaft-disk pinning— The improved expansion pin system ensures there is a positive, durable connection between disk and shaft. This reduces backlash and wear in the drive system, optimizing long-term performance. It also makes disassembly for maintenance quick and simple with no need for special tools.
New Spring-Loaded Shaft— The spring in the outboard shaft provides support to the drive train and disk, enabling the shaft to be installed in both horizontal and vertical orientations with no detriment to performance or cycle life. This complements the ability to mount the actuator on the left- or right-hand side, enabling access for any installation.Excellent Emissions Capabilities— The optional ENVIRO-SEAL® packing systems, are designed with very smooth shaft surfaces and live-loading to provide improved sealing, guiding, and loading force transmission. The seal of the ENVIRO-SEAL system can control emissions to below 100 ppm (parts per million).Sour Service Capability— Depending on material selection, some trim and bolting materials are available for applications involving sour liquids and gases. These constructions comply with NACE MR0175-2002, MR0103, and MR0175 / ISO 15156. Contact your Emerson Process Management sales office for more information.
Easy Installation— Line-centering clips engage the line flange bolts to simplify installation and provide for centering of wafer-style valves in the pipeline. End connections are compatible with EN and ASME standards.Excellent Shutoff Regardless of Pressure Drop— Both the S31600 (316 stainless steel) seal ring and the bidirectional PTFE seal ring with pressure-assisting sealing action ensure shutoff regardless of flow direction.Long Seal Life— The opening and closing path of the eccentric disk minimizes disk contact with the seal ring, thereby reducing seal wear, undue friction, and seating torque requirements.Reliable Flange Gasketing Surface— The seal retainer screws and retention clips are outside the gasket surface of the seal retainer. Spiral-wound or flat-sheet gaskets can be installed between the uninterrupted seal retainer face and the pipeline flange.
Integral Shaft-to-Valve Body Bonding— Standard valve construction includes conductive packing to provide electrical bonding for hazardous area applications.Powder paint as standard— The Emerson Process Manag mentTM powder paint finish offers an excellent corrosion-resistant finish to all steel parts.High Temperature Capability— The valve will operate at elevated temperatures, with the appropriate trim components.Shaft Retention— Redundant shaft retention provides added protection. The packing follower, anti-blowout ring, and shaft groove interact to hold the shaft securely in the valve body.Travel Indication— Additional travel indication can be achieved by using the indication line on the shaft, along with the disk position markings on the packing follower.
