Metso NelesAce is specifically for basis weight control
Metso says that basis weight control is one of the most critical applications for a valve in a paper machine and offers the NelesAce™ for this application. The unit consists of a reliable V-port segment valve, complete with a high-resolution step-motor-driven rotary actuator, limit switches and potentiometer.
The NelesAce control unit’s unique feature to run a valve with various step sizes, depending on the error between actual and desired flow rate, means any error can be eliminated quickly and accurately without overshooting. This helps to reduce settling time during grade change, for example.
The valve, a Metso R Series Vport segment valve, is available in sizes DN50-250/2-in. — 10-in. in a flangeless design, and DN50-500/2- in. — 20-in. in a flanged design.
The electro-mechanical actuator uses a bipolar stepping motor to accomplish discrete and repeatable angular movement for each step. There is only one size of actuator for the full range of valves offered. Valve position is clearly indicated by a feedback potentiometer that transmits an electrical signal to the display at the control unit.
Mechanical limit switches prevent over-travel. A hand-wheel is provided for manual operation.