The AR2000 Preheater/Miller is designed to heat and soften asphalt pavement and mill it to controlled depths. The patented heating system provides effective heat penetration to avoid fracturing of the aggregate during the milling process.
The Preheater/Miller incorporates a system for the addition of various rejuvenators, if required.
The Preheater/Miller’s drive system is hydraulic. The machine has three milling drums,and its components are assembled and welded onto a rigid, strong main frame.
The Preheater/Miller’s patented heating technology is the same as the Preheater’s. It combines high-velocity forced hot air with low-level infrared heat. The system incorporates a diesel fuel burner, combustion air turbo blower, recirculating hot-air blower and a stainless-steel heating plenum. The burner heats a large amount of air into the heat-insulated, stainless steel combustion chamber. The hot air is then forced into the heating tubes located in the insulated heating plenum. On the bottom of the heating tubes there are thousands of small holes through which the high-velocity hot air is blown onto the road surface causing thorough heating of asphalt. Since most of the oxygen from the fresh air is used for combustion, the hot air used for heating has low oxygen content, avoiding oxidation of asphalt binder.
Excess hot air is then vacuumed from the road surface by the recirculating hot-air blower and blown back into the combustion chamber to be reheated. About 10% of the air is exhausted to make room for fresh air needed for combustion, which is supplied by the combustion air turbo blower. Three cylinders are used to adjust the heating plenum.
The fully computerized flame-management system, combined with an advanced fuel-control system, ensures the reliability of the combustion-chamber flame for safe and continuous operation. The operator can monitor and control the temperature of hot air from the operating station.
The combination of economic diesel fuel with the hot-air heating system provides a major advantage over other hot in-place recycling equipment: the AR2000 offers significant cost savings, a safer environment for operators, and conservation of energy and natural resources. Under normal operating conditions, the system is virtually emission-free.
The two side milling drums and one centre milling drum can be adjusted to handle lane widths from 3.2 to 4.0 metres. The milling drums have a flexible hydraulic mechanism to control their movement. An automated depth-control feature regulates precise depths from 0 to 50 millimetres. The design of the milling drums allows for quick exchange of used cutting bits for efficient operation.
Three components – a 2.7 cubic metre additive tank, rejuvenator tank, and rejuvenator pump – form part of a computer-based additive control system. Based on predetermined values, the computer-based controller can adjust the rejuvenator pump output, and the operator can also control the addition of rejuvenator manually. The rejuvenator pump can accommodate a range of viscosity of oils. A propane gas burner is designed to heat the tank to reduce viscosity. The rejuvenator is spread on the windrow between the side milling drums and before the centre milling drum mills the pavement, which provides for thorough mixing.
The self-propelled Preheater/Miller is driven by hydraulic steering cylinders located on the front axle and rear tandem axle. These cylinders can be steered independently of each other to reduce the turning radius. The hydraulic variable displacement pump is attached to a 300 kW CAT engine through a pump drive. Using hydraulics, the drive mode can be easily switched between operation and travel mode. The train’s step-less speed control allows for easy adjustment of speed.
All tires are resistant to high heat; the front tires are switched to pneumatic tires during towing. The brake system on the front axle is operated pneumatically, and an additional parking brake is incorporated into the system for ease of operation.
A dedicated operating station is located at the rear of the machine. Instrumentation controls are clearly displayed and easily accessible to the operator. A swivelling chair provides excellent visibility.
Electrical control operation is designed 24VDC. Heavy-duty 24V batteries are charged by an onboard alternator.
Each AR2000 machine can be easily hitched to a tractor truck and transported at highway speeds between job sites.