Automated drymix plant now operational - NZ Engineering News

New Zealand’s first fully automated plant producing precisely formulated drymix cement-based products is now up and running in Onehunga, Auckland, according to Bhav Dhillon, General Manager of Cemix Limited (Drimix Division).

The control room was set up during the commissioning during which engineers from Finland, Holland and Australia came to New Zealand for well over five weeks. This went ahead without a flitch and is now completed.

The entire operations of the Raute plant are controlled by a Siemens PLC and the globally acclaimed Raute Batch Control software which can have weighing accuracies up to 10grams. The plant has one Logic Control Centre (LCC) and two Motor Control Centres (MCC). One of the salient features of the plant is that it handles dry powder material without using screw conveyors or air slides. Instead, it incorporates patented fluidisation technology which makes powders (sand and cement) flow like liquid, enabling the use of double flap butterfly valves for accurate and high speed dosing. Combining this with the advanced control system ensures that very high speed, accuracy and consistency can be achieved due to the self-learning capabilities of the automatic control system.

The plant’s automated bagging line is also fully operational, ensuring speed and reliability and the palletising robot is currently being programmed. The bags are filled, palletised and stretch wrapped in a fully automated line. The pneumatic debagging system for raw material intake is also operational, with raw materials being conveyed into their respective silos pneumatically.

The state-of-the-art fluid bed sand drying and cooling system has also been running flawlessly. This fully intelligent system constantly monitors the input and output sand temperatures and also the exhaust air temperature. This ensures that the product is dried and cooled to 55 degrees Celcius before discharging. If sand temperature is higher than 60 degrees, the performance chemicals added will simply disappear.

The first batches of product have been made and are currently being test marketed. Cemix’s Managing Director Geoffrey Clark comments, ‘We are getting better than expected response from our customers and are in the final stages of signing up substantial national level supply agreements. The tried and tested technology from Europe couples with support from our hi-tech lab, the only dedicated drymix products lab in the country, is a sure recipe for Cemix’s success in the drymix business.’

For further information contact: Cemix Limited (Drimix Division) Tel: 09 634 9365 or Email:

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