At a large aggregate plant, it's impressive to see miles of conveyors stretching high above the ground where screens are stacked on top of screens. Primary, secondary and tertiary crushers bust and grind material to near dust to be segregated into mountainous stockpiles. These giant anthills, silhouetted by the sunset, can be admired from the tops of catwalks as monuments to a job well done.
At a large aggregate plant, it's impressive to see miles of conveyors stretching high above the ground where screens are stacked on top of screens. Primary, secondary and tertiary crushers bust and grind material to near dust to be segregated into mountainous stockpiles. These giant anthills, silhouetted by the sunset, can be admired from the tops of catwalks as monuments to a job well done. The giant erection of steel is the envy of the neighbors, and a landmark to passing traffic. But anchored by tons of concrete, the plant is rendered immobile. The producer becomes a slave to his creation, forever searching for ways to bring more material to the monstrosity. After all, the plant isn't moving.
Yet some operators favor casting off these chains, realizing you can sometimes do more with less. While size is impressive, there's something to be said for portability and maneuverability. A portable plant goes straight to the source, eliminating transportation time and costs. Newer plants offer quicker setup and teardown. OEMs also are boasting access for maintenance, and higher production rates. You can even take a tracked plant for walks.
TRACKED- AND WHEELED-PLANTS BUILT FOR SPEED
? The Terex Cedarapids' Mobile Aggregate Crushing System uses larger crushers and screens than what are typically used in track-mounted or wheeled plants. Trailer designs can be permitted for travel throughout most of the United States. The crushing and screening units travel under 13 feet, 6 inches high and under 12 feet wide. Interplant conveyors are designed into the units so that separate transfer conveyors are not required. Folding conveyors and walkways set up using onboard hydraulics, thus eliminating the need for cranes or lifts. Also, large hydraulic support legs level and stabilize the units to speed setup.
The entire system uses industrial electric drives, so it can be powered by either generators or line power. The system's layout provides operator visibility of the entire circuit from a central pop-up control house. Belt wipers and skirted conveyors help minimize spillage. The control trailer is stocked with common parts and organized in a visual inventory management system. A furnished mechanics tool chest and a stocked hardware cabinet are included in the trailer.
Terex Minerals Processing Systems
? The NW300HPS portable plant from Metso was recently updated. Axle spacing was increased to 10 feet, and axle weight was reduced by 1,500 pounds for transport in California. Improved component access is coupled with guarding. An FS303CL screen that produces three finished products while feeding the HP300 cone crusher. A soft-start starter has across-the-line bypass and NEMA-rated components.
The NW300HPS also offers the Lubrinator system, a modified hydraulic and lubrication system with a compact design. The Lubrinator is mounted on the side of the chassis. The tank is protected by a lockable cover that uses gas shocks to assist the user in lifting and keeping the cover open during access, similar to a tailgate on an SUV.
The transfer chute can be used in closed circuit or rotated to the rear or side for use in open circuits.
? Inertia's 5066 Tracker has hydraulic-driven tracks and a removable triple axle with 72-inch spacing for ease of transportation. There is a 14-cubic-yard non-heaping hopper along with a 60-inch ◊ 18-foot vibrating grizzly feeder with a 4-foot grizzly section and variable-speed drive. The impactor has a feed opening measuring 42 ◊ 64 inches, which crushes large product and decreases the chance of bridged material.
A four-bar rotor allows two- and four-bar arrangements. The large open-style ribbed rotor delivers high inertia and requires less horsepower and fuel to operate. There are two adjustable aprons allowing for multiple reduction ratios with a more cubical product and fewer fines, the company says. The apron liners are reversible and interchangeable along with the housing liners.
The 42-inch ◊ 39-foot discharge conveyor has a motorized head pulley and is capable of 1,300 tons per hour. The Tracker has a built-in stand for an optional cross belt magnet to process rebar and other metal separation. The engine is a John Deere 400-horsepower Tier 3 with a 125 kiloWatt generator. This machine also features a remote clutch and track controls.
Inertia Machine Corporation
? Raptor XL300 and XL400 cone crushers by FLSmidth Excel can be customized as portable wheel-mounted or mobile track-mounted plants. The wheel-mounted plant options include rear discharge and rear feed-side discharge for both models. When combined with a horizontal 6-foot ◊ 20-foot, two- or three-deck screen, the XL300 can be configured into a closed-circuit crushing and screening plant. Both crushers can be configured with two- or three-deck horizontal screens that are 6 foot, 7 or 8 ◊ 20 feet, to provide open-circuit crushing and screening plants. Optional hydraulic run-on jacks level the plant into operating position after pulling on site.
The XL300 and XL400 cone crushers feature a high pivot point and large crushing stroke. The crusher line also employs hydraulics through an internal relief valve within the dual-acting tramp-release cylinders. Overload-sensing technology detects crushing force overload.
? Stedman's four-row cage mill allows aglime producers to meet most state aglime specifications in open circuit. It can produce aglime to any specification for both large and small producers, the company says. Feed does not have to be dry. The unit shown is a self-contained portable plant that includes motor control center and dust collection.
Material is loaded into the feed hopper or hoppers, conveyed to the cage mill, crushed and discharged out the side. Discharge is completely open and requires no screens or grate bars, eliminating the cleaning and replacement of discharge screens or grate bars. The four-row cage mill is available with capacities as low as 5 tph as much as 100 tons per hour.
? Lippmann-Milwaukee has launched a crawler-mounted crushing unit ó the Lippmann 3252 track-mounted mobile jaw plant. It employs a direct crusher drive gear transmission system to develop the Triple Power Match Drive System. Teamed with Lippmann's 3252 jaw crusher, the transmission system powers two rear output points while employing twin VDP pumps for hydraulics. The company says this reduces fuel consumption and offers greater system efficiency.
The jaw moves material through the chamber with forced-feeding action, resulting from the inward and downward eccentric movement of the swing jaw. Longer jaw dies and a larger eccentric means a reduction in nip angle and a more positive bite. The plant's wider, hydraulically lowered main conveyor ensures greater material discharge capacity. The plant's diesel engine complies with E.U. Stage IIIA/EPA Tier 3 emission regulations and offers low noise levels.
The plant differs from a crusher box that acts as the tie brace between chassis and frame, which can cause excess vibration to the jaw's bearing housing that could lead to bearing failure, main frame failure, or common structural problems under the feeder.
Lippmann fabricates the chassis of square, hot-rolled carbon steel. Numerous cross members prevent vibration fatigue and stress. Gearbox housing is fixed to the chassis module, just like a bulldozer's, so the track frames don't go their separate way when changing direction under severe load.
On the unit's Intelligent Control System, information is displayed on one screen with single-button process start, automatic process control and built-in fault diagnostics. Operation is by remote control from up to 300 yards. An override umbilical option for emergency or service use is available.
An extended track line is under development to eventually include a Lippmann 3650 track jaw, a 4248 track impact unit, a 5165 track impact unit, and a new size 3862 track jaw.
? Terex Canica has added portable, chassis-mounted vertical gear drive units to its vertical shaft impactors. The TXC 2050, 2300 and 2350 have production capacities of up to 600 tons per hour with feed sizes up to 8 inches. The vertical gear drive has a pinion gear drive system to rotate the crusher shaft, which eliminates the need for power-hungry hydraulic and quarter-turn drives when coupled with a diesel engine. It also allows for above-deck access to V-belts and drive sheaves. Crushers also can be driven by horizontally mounted electric motors.
All models can be configured with open-table anvils, enclosed-rotor anvils, and enclosed-rotor rock shelves for different material abrasiveness. The hydralid lid lifter and hydraulic lid swing mechanism makes opening and swinging the lid a one-person remote operation.