AUMA has launched its new line of explosion-proof variable-speed valve actuators for use in potentially hazardous environments.
The new SAVEx actuators for open-close duty and SARVEx multi-turn actuators for modulating duty, combined with intelligent ACVEx actuator controls, provide full control of the motor speed at any time.
In oil and gas applications, variable speed offers advantages for challenging valve control tasks, since it allows the optimum operating speed to be selected for each change of valve position. High positioning accuracy and optimised setpoint control considerably increase the effectiveness of pressure control valves in gas pipelines, for example. On multiport valves, variable-speed actuators aid rapid and accurate switch-over between ports.
Mechanical stresses on valve, actuator and pipeline are minimised by reducing the operating speed close to the end positions, allowing the moving element of the valve to make gentle contact with the seat. Pressure surges and cavitation effects in the pipeline can be avoided by using speed profiles.
When working in modulating duty, the actuator speed can be set to reduce progressively as the
valve position approaches the setpoint, giving a significant increase in positioning accuracy. Actuator speed can also be controlled by an external signal – either 4 20 mA analog or 0 – 100 % digital – to take full advantage of additional control variables or algorithms. A further option is speed synchronisation between two actuators.
valve position approaches the setpoint, giving a significant increase in positioning accuracy. Actuator speed can also be controlled by an external signal – either 4 20 mA analog or 0 – 100 % digital – to take full advantage of additional control variables or algorithms. A further option is speed synchronisation between two actuators.
The actuators are available in six sizes covering torques up to 1000 Nm. Speed ranges include 6 – 60 rpm, 12 – 108 rpm and 24 –116 rpm.
Image courtesy of AUMA