Forterra PrediktIR Case Study
Forterra was initially founded in the 1960s as Hanson’s UK building products division. In 1984 Hanson acquired the London Brick Plc, who had been producing bricks at the Kings Dyke brickworks in Whittlesey, near Peterborough since 1969. There followed numerous acquisitions and in 2015 Hanson sold the brick and block division, and Forterra was formed.
Their expertise lies in building products made from clay and concrete and their portfolio contains some of the most recognised and respected names in the construction industry including London Brick and Butterley.
When manufacturing bricks or pavers, it is critical to have the clay at the correct moisture level. Because clay is a natural product, coming directly from a quarry, the amount of moisture in the clay will be affected by recent weather and storage conditions.
This means that the moisture levels need to be constantly monitored and adjustments need to be made to the amount of water that is added. Traditionally this has been achieved by using a basic, manual test but this is a spot check, it is not a continuous method, and it is open to human subjectivity.
A moisture gauge from NDC Technologies uses a non-contact near-infrared (NIR) method to continuously measure the clay moisture levels with total precision to an accuracy of ±0.3%. The patented, dual detector design ensures a permanent, stable calibration, which is unaffected by any fluctuations in ambient temperature, light, and/or humidity, common in most brickworks.
Due to the accurate and reliable measurement, the result can be used as a critical control point for the process. Ultimately the measurement is used as part of an automated control loop to adjust the flow of water that is added during the manufacturing process.
We have recently purchased three PrediktIR moisture gauges from LIMAB UK to accurately measure the moisture content of the clay throughout the production cycle. The first gauge has been installed in the clay store, to monitor the initial moisture level of the clay arriving from the quarry. The second gauge has been installed above the main raw product infeed conveyor in the production shed, which feeds into the supply conveyor system. The third gauge has been fitted adjacent to our conveyor control office and is just after the grinding process, where the raw clay has been reduced in size ready for the presses, this is where the moisture content is at its most critical, just before the clay is formed into a brick. We used to rely on a moisture balance for the moisture reading, but this can take up to 30 minutes, which is just too long. By using the PrediktIR moisture gauges, we are now able to monitor the live moisture levels from all three gauges, simultaneously from one central point. We conducted a trial comparing the data from the PrediktIR and two moisture balances. We had a good correlation, so we could see the gauges were accurate, stable and it gave us a good insight into the process. Overall, we are very pleased with the accuracy and the reliability of the gauges and we were impressed by LIMAB UK’s evident industry experience and application expertise.
Andrew McGillivray Engineering Manager, Forterra (Kings Dyke Works)
To gain a better understanding of the process and to assess the performance of the on-line moisture gauge, a trial was set up measuring clay moving along a conveyor. Eight or nine moisture measurements a day were taken over a nine-day period.
Using best practice methods to ensure the most dependable results, spots check were made using two brands of moisture balance and these were compared with the on-line measurements from the NDC Technologies’ PrediktIR moisture gauge taken at the same point in time.
Graph Showing Correlation Between Two Moisture Balances and NDC Technologies’ PrediktIR Moisture Gauge
If you would like to find out whether a NIR moisture gauge could improve your production processes and quality control procedures, then please do get in touch