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Valve Positioner Connected to an Active Damping System

IP.com Disclosure Number: IPCOM000186678D
Published in the IP.com Journal: Volume 9 Issue 9A (2009-09-11)
Included in the Prior Art Database: 2009-Sep-11
Document File: 3 page(s) / 144K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

Control valves are being used in many industrial applications. In order to achieve optimally controlled processes, the valves need to be positioned quickly and accurately. Such valves are controlled by so called valve positioners. Valve positioners control valve actuators, which move the valve to the set position. By doing this, the fluids flowing through the valves are controlled. In pneumatic valve actuators air is used to move the valves. Due to the elastic nature of air, the valves cannot be driven quickly to a fixed position and stopped there. Usually the valve's working parts travel longer distances than desired. This behavior is called overshooting. Another cause for overshooting is stiction (static friction). As a result of stiction the valve keeps oscillating around the set position. Overshooting is responsible for both, a decreased performance of process control and accelerated wear of the valve. In fact, over-operation of the valve is the main reason for wear and related costs. In state of the art Systems the performance and accuracy of valves has been improved by using piezoelectric components in the valve positioner to fine tune the air flow to the valve actuator. Additionally, a special control system is known, which can be used for identifying stiction and adjusting the control signal to the valve.

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Valve Positioner Connected to an Active Damping System

Idea: Min Guo, CN-Beijing; Hongwei Yang, DE-Karlsruhe; Shunjie Fan, Ph.D., CN-Beijing; Haoyuan
Cai, Ph.D., CN-Beijing

Control valves are being used in many industrial applications. In order to achieve optimally controlled processes, the valves need to be positioned quickly and accurately. Such valves are controlled by so called valve positioners. Valve positioners control valve actuators, which move the valve to the set position. By doing this, the fluids flowing through the valves are controlled. In pneumatic valve actuators air is used to move the valves. Due to the elastic nature of air, the valves cannot be driven quickly to a fixed position and stopped there. Usually the valve's working parts travel longer distances than desired. This behavior is called overshooting. Another cause for overshooting is stiction (static friction). As a result of stiction the valve keeps oscillating around the set position. Overshooting is responsible for both, a decreased performance of process control and accelerated wear of the valve. In fact, over-operation of the valve is the main reason for wear and related costs. In state of the art Systems the performance and accuracy of valves has been improved by using piezoelectric components in the valve positioner to fine tune the air flow to the valve actuator. Additionally, a special control system is known, which can be used for identifying stiction and adjusting the control signal to the valve.

In the following a solution to the described problem is proposed, which incorporates an active damper inside the valve system. Thereby the damper can be installed...