An Asian fibreglass manufacturer uses electric valve actuators at several of its plants. Previously, a locally made control valve and actuator was used, which suffered from poor performance and inaccurate valve control.
Raw fibreglass material in pellet form is transported from a hopper into a furnace and melted. Globe control valves must accurately control the ratio of natural gas and oxygen supplied to the furnace to melt the raw glass. The correct mixture ensures good combustion and provides a lean burn, saving both gas and oxygen. The precision of the CVA now delivers this accurate control. In the photograph, the natural gas pipes are yellow and the oxygen pipes are grey.
The melted material is then extruded into fine threads of fibreglass which is sprayed with water to cool. The cooled threads are reeled into coils and sold as the finished product. These threads are extremely strong and are used in the manufacture of pipes, tanks, car parts and boats, amongst others.
The CVA offers a highly accurate and responsive method of automating control valves, without the complexity and cost of a pneumatic supply. As this fibreglass application illustrates, an increased focus on production costs and efficiency means that accurate control is vital. With resolution figures better than 0.1% and the ability to eliminate position overshoot, the Rotork CVA helps to maximise product quality and plant capacity.
In keeping with Rotork's 'sealed-for-life' philosophy, CVA set-up and calibration is carried out non-intrusively with a Bluetooth™ enabled PDA using the freely downloadable Rotork Enlight software, so that no access is required to the main electronics compartment during commissioning. In addition, the terminal compartment is separately sealed, eliminating the risk of moisture ingress during installation.