Infrared Temperature Measurement | Combustion & Environmental Monitoring

Roadstone/Asphalt Industry

The schematic diagram below illustrates the essential features of a typical Roadstone/Asphalt plant. The areas highlighted offer measurement reference points and the best choice of instrument, where AMETEK Land's infrared thermometry know-how can really benefit you.

If your specific area of interest is not covered here, our engineers will be pleased to discuss your requirements with you.

Typical temperature measurement points on a Roadstone Plant

1. Drier Exit Chute


A radiation thermometer is normally positioned in the drier exit chute to monitor the temperature of the aggregate as it leaves the drier. Utilizing a radiation thermometer permits closed loop control to set burners in the drier minimising fuel wastage and maximising product quality.

  • Fast response provides automatic burner control.
  • Maximise fuel savings.
  • Improve product quality.
  • Unlike thermocouples they are not damaged or eroded by the moving aggregate.

2 - Mixed Material (Batch Heaters)


When using the batch process, automatic burner control is not possible. Knowledge of the hot stone temperature and its subsequent effect on the binder and filler temperature is a useful aid to process control. Once the material is in the mixer it is not possible to make temperature adjustments. Measurement here does however, permit rejection of a single batch if it falls outside the specified temperature limits, avoiding contamination of acceptable material.

  • Maintain product quality.
  • Minimises 'out of specification' product dispatched.
  • Reduces risk of fire in the mixer.

3. Coated Roadstone Mixer Exit


Installing a radiation thermometer at the mixer exit minimises the risk of rejection at the laying point due to being outside specified temperature limits. The temperature of each load can then be recorded on a chart or stored by computer. This is a simple installation, widely used and highly successful.

  • Rapid temperature measurement of finished product prior to despatch.
  • Operator free measurement system.

4. Drum Mix Asphalt Plants


With the high level of continuous production, any slight fluctuation in the final mix temperature can result in batch rejection. Measurement at the discharge chute can be fed to a chart recorder or linked to an automatic burner control system using a suitable controller.

  • Product quality is constantly maintained.

5. Hot Storage Bins


For large capacity drum mix plants, coated roadstone is stored in heated storage bins, often overnight. A Roadstone thermometer positioned at the exit door monitors temperatures of the discharged material to minimise the risk of batch rejection, due to it being out of the specified temperature range.

6. Roadstone Laying Point

One final check can be made here on the temperature of the product. On-site quality engineers can make spot checks using portable equipment. Failure to maintain quality control here could lead to uneven road rolling, premature wear and subsequent expensive repair.