Cement plants generally use Rotary Valves for extraction of raw meal from storage silos. This valve is operated by a geared motor with a RDOL starter through the plant PLC.

In this conventional system the rotary valve is operated through the PLC system, with feedback of flow from solid flow meter or from a feed control system under auto operation. In this method, accuracy of flow is dependent on the position of the rotary valve, set by the PLC, and varies depending on the backlash of the gear box.

Sometimes due to the weight of the material on the rotary flap, the position gets altered, thereby triggering PID action constantly. In order to avoid chattering of the RDOL feeder due to PID action, a Dead Band is set in the Control System, within which, corrective action is not taken by the automation system. This results in a wide control band which often causes variation in the quantity of raw meal and consequently the quality of the clinker produced.

The customer, a leading cement manufacturer, approached Kasa Anlagen to suggest a solution to overcome this problem. Kasa Anlagen did a detailed study and after a thorough analysis developed a solution for the customer. After implementation of this solution the customer was able to finely control the quantity of raw meal in the 0-320 tons range. Manual mode of operation was also introduced in the system where jogging operation of the motor was provided for precise adjustment and positioning. All the above parameters were visualized in the main plant SCADA.

This solution enabled the customer to accurately control the flow and the output from the kiln was uniform in quality. The customer was able to recoup the investment within a very short period and is now planning to introduce this in all his lines.

For more information on this and other automation solutions please email sales@kasaanlagen.com or call +91-44-42926600-6699.