Control-Disk Rotary Valves
Fisher Control-Disk valves provide precise control across a broad range of applications.
Fisher Control-Disk valves provide precise control across a broad range of applications.
The Control-Disk rotary valve offers excellent throttling performance. An equal percentage flow characteristic provides an improved throttling range comparable to that of a segmented ball valve. This improved capability allows you to control closer to the target set point, regardless of process disturbances, which results in a reduction in process variability.
A Control-Disk valve is ideal for applications that involve fast processes and varying pressure drops, such as in hydrocarbon, refining, chemical, pulp and paper, and metals and mining industries.
With a contoured edge on one side, the unique and patented disk creates a flow clearance to give the Control-Disk valve an inherent equal percentage characteristic. Computational fluid dynamics (CFD), verified by flow testing, show the Control-Disk valve’s ability to reduce dynamic torque.
The two-piece shaft allows for an enlarged center flow path. A drive shaft is connected to one side of the Control-Disk and an outboard shaft is connected to the opposite side. The spring in the outboard shaft positions the drive train and disk when the shaft is in vertical or horizontal orientation.
Equal percentage disk reduces operating torque at peak angles of disk opening. The Control-Disk is held in by improved shaft-disk pinning that provides minimal backlash and wear.
Low friction, low wear PEEK/PTFE bearing is standard.
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).
Process gain defines the relationship between changes in process output and input. The travel over which process gain stays between 0.5 to 2.0 is a valve’s control range. When process gain is not within 0.5 to 2.0, poor dynamic performance and loop instability can occur. Control-Disk valves have a wide control range of 15–70% and excellent throttling control.
