Cat PM820, PM822, and PM825 cold planers designed for power, productivity, safety, and low operating costs

By MEq February 9, 2018 01:27

The new Cat PM820, PM822, and PM825 cold planers are designed to be highly productive, highly maneuverable, half-lane milling machines capable of controlled full-depth removal of asphalt and concrete pavements in a single pass. Operating weights for the new models range from 36 130 to 37 500 kg, and cutting widths from 2 010 to 2 505 mm. All three new machines use the Cat C18 ACERT engine, rated at 563 kW (755 hp), meeting EPA Tier 4-Final/EU Stage IV emission standards, and iso-mounted to reduce vibration.

The high-horsepower C18, with an advanced turbo-charging and air-to-air after-cooling system, responds quickly to operating demands while keeping exhaust temperatures low and maintaining needed airflow for optimum efficiency and reduced emissions. For added efficiency, the cooling system uses an on-demand, variable-speed fan that draws ambient air from the top of the hood and through the cooling package, then expelling heated air from the rear of the machine—directing air away from the cab for operator for safety and comfort. The system also reduces temperatures in the engine compartment.

Drive system/undercarriage
The PM820, PM822, and PM825 are hydrostatically driven by two variable-displacement propel pumps supplying oil to a variable-displacement motor at each track. Drive motors are piston-type and automatically control displacement, providing optimum torque for work or optimum speed for maneuvering.

The drive tracks—based on durable, proven, Caterpillar designs and components—are 1 788 mm long and 305 mm wide, featuring replaceable, bolt-on polyurethane track pads for long service life. Track tension automatically adjusts to ensure optimum operation.
Four-mode steering is standard, with an electronic control module that processes inputs from sensors on the front and rear tracks, along with input from steering-selector controls. The system provides precise, simultaneous track movement in the crab- and coordinated-steering modes, while automatically realigning the rear tracks to center when the front-tracks-only steering mode is selected. In the coordinated mode, the inside turning radius is a tight 2.0 m, providing exceptional maneuverability in confined spaces.

Cutting system
The rotor is equipped with durable, three-piece, quick-release tool holders and carbide-tipped cutting bits arranged in a chevron pattern for maximum breakout force. Optional rotor systems are available, as are Cat Diamond Bits for enhanced cutting performance in specific applications. The cutting chamber features a design that facilitates material flow, reduces wear on the chamber, and provides flush-cutting capability.

Chamber side plates move via independent hydraulic cylinders equipped with position sensors, ensuring that the side plates float at the proper level and eliminate binding. The hydraulically operated anti-slab device protects the collecting conveyor and ensures an optimum discharge opening to the rotor chamber. The chamber also features a right-side hinged door that provides access to the rotor. The moldboard, side plates, and anti-slab device all feature raise, lower, float, and hold functions. The system eliminates the need for a wire sensor by enabling the entire length of the side plate to function as an averaging ski for grade matching.

Three cutting settings, controlled electronically from the keypad, are available to match rotor speed/torque with operating conditions. A standard Automatic Load Control feature enhances machine productivity via an electronic control module that continually evaluates engine speed and regulates propel speed as required to maintain performance for maximum output.

Conveyor System
The seamless collecting-conveyor belt, with 32-mm high cleats and a width of 850 mm, is driven by a high-torque, variable-speed hydraulic motor that provides adjustable control of the loading conveyor to ensure proper discharge. A large chamber-discharge opening clears out the cutter box quickly and effectively controls fine particles. An optional system uses a grease cylinder to adjust belt tension and tracking (facilitating adjustment and reducing crew exposure to the spinning belt), but a conventional adjusting-screw system also is available.

A standard water-spray system lubricates the conveyor belt and assists with control dust. A centrifugal pump supplies water to the cutting chamber via spray nozzles, which spray in a flat-fan pattern to cool cutting bits. Nozzles are easily removed for inspection and replacement without tools. The spray system automatically activates when the rotor is engaged and the machine is moving forward, a feature that conserves water, which is triple filtered. A gauge monitors water pressure, and a low-water-level indicator helps manage water stops. Also, an onboard winterization system is included, providing a simple method for purging waterlines with pressurized air.
The 3400-liter water tank can be filled from standard wide-fill openings on top of the machine, or from the standard ground-level port at the rear of the machine. A side-fill port is optional, allowing adding water while the machine is operating. A water-transfer pump is available to facilitate additional filling options.

Cat Grade Control
The PM820, PM822, and PM825 can be equipped with the optional, integrated Cat Grade Control system, which is a 2D-capable/3D-ready grade-and-slope system that automatically controls a preset rotor depth and cross slope. The system can be enhanced for full 3D control with the addition of optional equipment.

Cat Grade Control can be configured with contacting or non-contacting grade sensors including Cat sonic sensors and mounting hardware, the side plate position or optional inboard ski. Machines can be set up either to control grade on both sides, using any combination of sensors, or, set up to control grade on one side and slope on the other. The system allows changing sensor arrangement during operation with simple commands.

Operator’s environment
The operator’s station features dual operating controls, including upper-conveyor controls and rear- track steering controls. An ergonomic instrumentation layout is designed for ease of use, and the touch-screen display is visible in all lighting conditions, with keypads backlit for low-light operation. The touch-screen display provides easy-to-read gauges, function indicators, and warning indicators, as well as displaying video from optional remote cameras.

A computerized monitoring system includes electronic control modules that constantly monitor system pressures and engine conditions with multiple modes of operation. The system can provide self-diagnostics and fault codes to the touch-screen display. An optional second display provides an additional monitor for machine functions.
The new machines are equipped with perimeter lighting, allowing safe low-light operation. An LED lighting system is available. In addition, the operator’s platform has floor lighting that activates with a button push from any control station for visibility when accessing the machine in low light conditions. An optional remote camera system, using either one or two magnetically mounted cameras, provides views to the front and/or rear of the machine.