Ultra-Dynamics has recently commissioned three automatic water addition control systems at pug mills in quarries.
The automatic water addition control system consists of:
- ultraMOIST Microwave Moisture Monitor for moisture measurement of raw feed
- Beltscale for mass flow of raw feed
- Control software to calculate the water flowrate for optimal product moisture
The operator inputs a set point for the required product moisture content, this is usually based on the customer requirements for e.g. optimal product packing characteristics for road base material.
ultraMOIST measures the moisture of the raw feed material as it is transported to the pugmill and uses a mass flow signal from an adjacent beltscale to calculate the additional water needed to bring the product moisture to the required level.
The control software automatically calculates the additional water needed and sends a signal to a flow control valve or pump to regulate the water addition.
Two types of control system have been supplied. For plants without a DCS the control system is PC based and operator interface is based on simple keystrokes.
The other type of system utilises the on-board PLC for interface with the plant control system to control a flow control valve or water pump VSD.