The benefits of precise moisture control
- Grain can be stored safely for longer
- Minimises the amount of energy required to dry the grain
- Maintains the nutritional value and taste
- Reduces harvesting losses such as cracked kernels
- Reduces dependency on weather conditions for harvesting
Where to measure moisture
Hydronix sensors are used to measure the moisture of the material entering and exiting the dryer. For a system drying material with a reasonably consistent incoming moisture one sensor can be used on the output of the dryer. The sensor’s output can be used as the process variable of a feedback control loop for the dryer.
In Figure 1, Hydro-Mix XT sensors were installed in a re-circulating dryer (locations 4 and 6); using a Hydronix Ducting System to measure the moisture of the grain precisely throughout the batch, allowing the automation system to control the dryer accurately until the required moisture content was achieved.
- Wet grain is delivered with higher moisture.
- The material is elevated to feed the dryer.
- The diverter redirects the material into the dryer or to the silo.
- A moisture sensor is installed at the inlet of the dryer. In this location, the sensor enables the drying parameters (feed-forward) to be adjusted based on the material’s moisture.
- The material is dried.
- A moisture sensor is installed at the output of the dryer to enable precise PID feedback loop control.
- The material is elevated.
- Depending on the measured moisture level, the material is either diverted to the silo for storage or recirculated to the dryer for further drying.
Result after installing the sensor
Although a well-calibrated system will achieve accuracies better than ±0.5%, the results were obtained from the output of a dryer processing barley, where an average accuracy of ±0.17% was achieved.
The moisture range was limited as the dryer controller was operating to maintain a target slightly lower than 12.5% to make the barley suitable for long-term storage.
Summary
Drying grain to a consistent target requires highly accurate sensors that can provide precise and repeatable measurements, resulting in a consistent product a reduction in spoiled or wasted material and better efficiency.
Hydronix sensors, such as the Hydro-Mix XT and Hydro-Mix XT-EX offer a purpose built, robust and durable solution for grain drying and processing applications. These sensors can significantly increase profitability through waste reduction, yield maximisation and efficient use of energy.
