Measuring asphalt production temperatures
The new, rugged RT8A infrared thermometer from Land Instruments International is the company's latest product for monitoring coated-stone temperature throughout the production process to ensure product quality and minimize energy costs. The outcome of over 25 years' experience of the roadstone industry, the stand-alone RT8A range encompasses four models covering temperatures from O°C to 500°C.
A comprehensive choice of mounting and protection accessories from the well proven System 4 range makes it easy to install the thermometer at the optimum point in the process. The RT8A can then be integrated directly into a simple two wire 4-20mA current loop with low-cost indicators, controllers and recorders for measuring, monitoring or control purposes.
The protection afforded by the robust IP65/NEMA 4X-rated housing can be supplemented by optional cooling and lens-purging facilities when required, while accurate, reliable and stable temperature measurement is assured by the RT8A thermometer's response time, which is adjustable from Is to 10s and offers accuracy within <0.5% of span, as well as minimal drift with change in ambient temperature of <1.5°C per 100C.
According to Land Instruments, at all points of the manufacturing process the RT8A infrared thermometer is a superior alternative to thermocouples, which are soon damaged and worn by contact with the product, respond too slowly and introduce lags into the system that result in poor control.
At the dryer exit chute, the thermometer sights on to a stream of aggregate. The RT8A output can be used to indicate aggregate temperature, or utilized in a closed-loop control system to control the burner, thus minimizing fuel wastage and maximizing efficiency while controlling aggregate temperature.
During mixing, the batch nature of the process precludes automatic burner control, but knowledge of the hot-stone temperature in the batch heater and its subsequent effect on binder and filler temperature is a useful aid to process control. Once in the mixer, the temperature of the material cannot be adjusted, but again, measurement at this point permits rejection of a single batch if it falls outside temperature specification limits, avoiding contamination of acceptable material.
Similarly, installing an RT8A thermometer at the mixer exit sighted on to the stream of coated roadstone as it falls from the mixer/storage bin into the delivery vehicle provides a final opportunity to reject out-of-specification product.
Temperature control is especially critical in continuous-production drum-mix asphalt plants, where even slight fluctuations in final mix temperature can result in large volumes being rejected. In this situation, the RT8A thermometer is mounted to sight on the stream of coated material as it leaves the discharge chute prior to the elevator system. The thermometer output can also be fed into a chart recorder, or used to control an automatic burner-control system.
Land Instruments Internationol, Infrared Temperature Measurement, Dronfield,
S. Yorks S18 IDJ, tel: (01246) 417691; fox (01246) 410585;
email: infraredsoles@landinst.com; website: www.landinst.com
A comprehensive choice of mounting and protection accessories from the well proven System 4 range makes it easy to install the thermometer at the optimum point in the process. The RT8A can then be integrated directly into a simple two wire 4-20mA current loop with low-cost indicators, controllers and recorders for measuring, monitoring or control purposes.
The protection afforded by the robust IP65/NEMA 4X-rated housing can be supplemented by optional cooling and lens-purging facilities when required, while accurate, reliable and stable temperature measurement is assured by the RT8A thermometer's response time, which is adjustable from Is to 10s and offers accuracy within <0.5% of span, as well as minimal drift with change in ambient temperature of <1.5°C per 100C.
According to Land Instruments, at all points of the manufacturing process the RT8A infrared thermometer is a superior alternative to thermocouples, which are soon damaged and worn by contact with the product, respond too slowly and introduce lags into the system that result in poor control.
At the dryer exit chute, the thermometer sights on to a stream of aggregate. The RT8A output can be used to indicate aggregate temperature, or utilized in a closed-loop control system to control the burner, thus minimizing fuel wastage and maximizing efficiency while controlling aggregate temperature.
During mixing, the batch nature of the process precludes automatic burner control, but knowledge of the hot-stone temperature in the batch heater and its subsequent effect on binder and filler temperature is a useful aid to process control. Once in the mixer, the temperature of the material cannot be adjusted, but again, measurement at this point permits rejection of a single batch if it falls outside temperature specification limits, avoiding contamination of acceptable material.
Similarly, installing an RT8A thermometer at the mixer exit sighted on to the stream of coated roadstone as it falls from the mixer/storage bin into the delivery vehicle provides a final opportunity to reject out-of-specification product.
Temperature control is especially critical in continuous-production drum-mix asphalt plants, where even slight fluctuations in final mix temperature can result in large volumes being rejected. In this situation, the RT8A thermometer is mounted to sight on the stream of coated material as it leaves the discharge chute prior to the elevator system. The thermometer output can also be fed into a chart recorder, or used to control an automatic burner-control system.
Land Instruments Internationol, Infrared Temperature Measurement, Dronfield,
S. Yorks S18 IDJ, tel: (01246) 417691; fox (01246) 410585;
email: infraredsoles@landinst.com; website: www.landinst.com
