DESCRIPTION

Technical Description

Control valves are key components of process engineering systems. They act as an actuator and create a link between the controller and the system. Control valves are generally used for regulating flows of gases or liquids. Optimum control loop design depends on a sound knowledge of control valve behaviour as well as knowledge of the controlled system response.

The mobile test stand permits investigation and testing of different control valve models. A water circuit with a pump and tank is provided for this analysis. Connections permit integration of the valve under test into the water circuit. The flow rate is adjusted by a gate valve and recorded by an electromagnetic flow rate sensor. Two pressure sensors are used to measure the pressure upstream and downstream of the control valve.

The supply pressure for electro-pneumatic valves can be adjusted by a pressure regulator on the switch cabinet. The manipulating variable can be set on potentiometers as a current signal. The position feedback from the valve is also returned as a current signal. Motorised valves are actuated by way of pushbuttons. A resistance teletransmitter measures the valve stroke.

Data acquisition software can be used to plot and evaluate valve characteristics and step responses on a PC in a user-friendly way.

The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Learning Objectives / Experiments

Together with control valves RT 390.01 - RT 390.06
- demonstration and functional testing of control valves
- determination of Kv and Kvs values
- plotting valve characteristics
- dynamic response of control valves
  * plotting step responses
- influence of supply pressure on pneumatically operated valves
- maintenance and adjustment