Challenge:  Evaluate different actuators for an upcoming plant expansion.

Results:  

There are many factors to consider when selecting the type of actuator to be used with valve applications. When making a choice between pneumatic vs. electric actuators, one soon realizes that a pneumatic actuator is less expensive and offers a faster blade actuation time. An electric actuator is more expensive and provides a slower actuation time. However, one must additionally factor the cost to manufacture compressed air and problems that may exist (especially in colder, northern areas of the country) in maintaining clean, dry air or keeping air lines from freezing during the winter months. In “problematic air” applications, the more expensive electric actuator may become the actuator of choice.

If the valve blade will be required to be positioned in mid-stroke, allowing the valve to “meter” material through the valve, a potentiometer or linear transducer will be required to determine the position of the gate. A controller will also be needed.

Vortex offers an Infinite Variable Position (IVP) Controller that may be used to control blade position. It is powered from a 115 – 240 VAC 50/60 Hz power source. It accepts either a 4 – 20 mA or 0 – 10 Volt input signal to identify or control the blade position.

In the case of the application pictured, the producer ordered the Vortex position controller because it provided a cost savings over ordering internal controllers supplied by the electric actuator manufacturer. Another advantage of the Vortex controller was its ability to be easily switched to manual operation and individually controlled at each gate. For this application, the customer wanted that added option.

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