Brochure

Innovation in Design
The unique disk with a contoured
edge on one side creates a flow
profile giving Control-Disk valves
an inherent equal percentage
flow characteristic that enables
precise, throttling performance
over a wide control range.
2 | Fisher
®
Control-Disk Valves
Performance Over a Wide Control Range
When selecting a control valve, there are several variables that need to be considered.
To find out if Control-Disk valves are ideal for your application, ask your Emerson sales contact.
F
isher
®
Control-Disk
™
valves are designed for precise control,
reliability, and to minimize the total cost of ownership.
They fit a broad range of applications in all industries and
are available with a choice of different valve constructions and
sizes up to NPS 36.
Precise Control
Control-Disk valves are ideal for processes that require precise,
throttling control performance. They can control closer to the
target set point, regardless of process disturbances, which results
in a reduction in process variability. There is minimal lost motion
between Fisher actuators and Control-Disk valves because of
splined shaft connections and clamped levers. With less chance of
overshoot, you can produce more on-specification end product.
The unique equal percentage technology in Control-Disk valves
enables precise control by providing a wide control range of
15–70% of valve travel. This range is similar to segmented ball
valves or sliding-stem valves. High performance butterfly valves
(HPBVs) are typically limited to only a 30–50% control range.
4.0
3.0
0.0
1.0
2.0
0% 20%
40%
60%
80%
100%
CONTROL RANGE
OF HPBV
CONTROL RANGE
OF CONTROL-DISK VALVE
Optimum
Process Gain
Wide Control Range
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.