Control valve positioners having improved operating characteristics
First Claim
Patent Images
1. A control valve assembly comprising:
- a positioner/actuator comprising a valve actuator having an actuator position and a positioner for controlling said actuator position; and
a control valve having a characteristic fluid flow rate passing through it as a function of time in response to a travel speed of said actuator, said positioner including an electronic control circuit for modifying the travel speed of said actuator as a function of time to produce a desired rate of change in fluid flow through the valve as a function of time in response to a specified control signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A control assembly includes a positioner/actuator and a control valve. The positioner/actuator includes a valve actuator and a positioner for controlling actuator position and speed in response to a control signal. The control valve has a characteristic flow rate as a function of time. The positioner may include an electronic control circuit for modifying the travel speed of the actuator to produce a desired flow rate as a function of time. The positioner may determine an error between a desired actuator position and an actual actuator position and apply a correction signal to reduce the error. The correction signal is asymmetric with respect to error polarity.
-
Citations
17 Claims
-
1. A control valve assembly comprising:
-
a positioner/actuator comprising a valve actuator having an actuator position and a positioner for controlling said actuator position; and a control valve having a characteristic fluid flow rate passing through it as a function of time in response to a travel speed of said actuator, said positioner including an electronic control circuit for modifying the travel speed of said actuator as a function of time to produce a desired rate of change in fluid flow through the valve as a function of time in response to a specified control signal. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A control valve assembly comprising:
-
a positioner/actuator comprising a valve actuator having an actuator position and a positioner for controlling said actuator position in response to a control signal; and a control valve having a characteristic fluid flow rate as a function of said actuator position, said positioner comprising means for determining an error between a desired actuator position and an actual actuator position and means responsive to said error for applying a correction signal to said actuator to reduce said error, said correction signal having a first characteristic determining an actuator speed when said error is positive and a second characteristic determining the actuator speed when said error is negative, wherein the first and second characteristics of said correction signal are different. - View Dependent Claims (7, 8, 9, 10)
-
-
11. A control valve assembly comprising:
-
a positioner/actuator comprising a valve actuator and a positioner for controlling actuator position and speed in response to a control signal; and a control valve having a characteristic fluid flow rate passing through it as a function of said control signal, said positioner including an electronic control circuit for modifying the travel speed of said actuator as a function of said control signal to produce a desired rate of change in fluid flow through the valve as a function of time. - View Dependent Claims (12)
-
-
13. A control valve assembly comprising:
-
a positioner/actuator comprising a valve actuator and a positioner for controlling actuator position in response to a control signal; and a control valve having a characteristic flow rate as a function of said actuator position, said positioner comprising means for determining an error between a desired actuator position and an actual actuator position and means responsive to said error for applying a correction signal determining an actuator speed to said actuator to reduce said error, said correction signal being asymmetric with respect to polarity of said error. - View Dependent Claims (14, 15)
-
-
16. In a control valve assembly comprising a positioner/actuator including a valve actuator and a positioner for controlling actuator position and actuator speed in response to a control signal, and a control valve, a method for positioning said control valve comprising the step of:
modifying the travel speed of said actuator as a function of said control signal to produce a desired rate of change in fluid flow through the valve as a function of time.
-
17. In a control valve assembly comprising a positioner/actuator including a valve actuator and a positioner for controlling actuator position in response to a control signal, and a control valve, a method for positioning said control valve comprising the steps of:
-
determining an error between a desired actuator position and an actual actuator position; generating a correction signal to reduce said error, said correction signal determining an actuator speed and being an asymmetric function of error polarity; and applying said correction signal to said actuator.
-
Specification