Ben Fletcher, product manager at Emerson, explained the design intent behind the 8590 butterfly valve: “Our goal was to give application engineers the ability to combine a single valve platform with a selection of proven technologies to control a diverse range of CL600 process demands.”
“As an example, several dynamic disk seals are available in the 8590 design to meet temperature conditions that range from low-to-moderate up to 538°C (1000° F). Severe service and cryogenic applications can be met as well with the appropriate metal-polymeric or rugged stainless steel seal construction,” Fletcher added. “Since one valve design meets several needs, overall valve engineering, purchasing, installation, operation and maintenance costs become less. “
Utilizing a lugged body design across the CL600 size range of NPS3 – NPS24, the 8590 can incorporate a splined shaft that accepts either a spring-and-diaphragm or pneumatic piston actuator. It is also available with either a square or keyed shaft that combines with handlevers, handwheels or pneumatic piston actuators.
The pressure-assisted design of the 8590 disk seals provides tight shutoff and permits the use of smaller, less expensive actuators in meeting full ASME B16.34 shutoff capabilities.
The 8590 offers true bidirectional shutoff, which means that torque necessary to open and close the valve remains constant regardless of the differential pressure across the disk. Slam-shut conditions are not created as the disk nears its seat, which extends seal life and avoids actuator and piping damage.
Besides shutoff given by the choice of elastomer and metal disk seals, the optional ENVIRO-SEAL packing system combines with the valve’s micro-smooth shaft surface to keep emissions below 100 parts per million (PPM). Yet another extreme 8590 capability involves sour liquids and gases, with trim and bolting materials available to comply with NACE MR0175-2002, NACE MR0175-2002-2003, MR0103, and MR0175/ISO 15156.
With a CL600 rating per ASME B16.34, the valve’s face-to-face dimensions meet EN558, API609, MSS-SP68, and ASME B16.10 standards. The valve body self-centres on the line flange bolts as a fast, accurate means of centring the valve in the pipeline.
For more information, visit www.Fisher.com