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McLanahan - Direct Drive Crushing Sizers (DDC)
Direct Drive Crushing Sizers, specifically McLanahan DDC-Sizers, provide primary, secondary and tertiary reduction of friable, low silica materials such as coal, salt, gypsum, phosphate, limestone, bauxite, petroleum coke, lignite, trona, carbon anodes, oil sands, clay, shale and more. DDC-Sizers have a direct drive arrangement and low-profile design that allows wheel mounting for a movable configuration. The preferred method of installation is to mount the unit on rails with a non-rigid connection between the feed and discharge chutes. Since the drives are attached to the mainframe of the sizer, the entire unit can be rolled out from the feed stream to facilitate maintenance.
McLanahan is the world’s most experienced manufacturer of Double Roll Crushers and our DDC-Sizers operate around the globe. McLanahan DDC-Sizers are designed and manufactured to be more efficient and deliver a better total cost of ownership through the life of the equipment. McLanahan supports our DDC-Sizers for the life of the equipment and uses standard, readily available motors, gearboxes and couplings.
All segments and sizing combs in the DDC-Sizers are designed to be interchangeable throughout the machine. Unique to McLanahan Primary and Secondary DDC-Sizers is the hydraulic product size adjustment, which gives producers versatility if the product size requirements change.
How DDC-Sizers WorkDDC-Sizers use an electric motor to drive the gear reducer, which is mounted directly to the roll shaft. The motor and reducer are protected via a fluid coupling fitted with a thermal element and underspeed sensors to eliminate the risk of shock loads or stall events transferring through to the drive components. The crushing rolls can be rotated either inward or outward at slow speed and high torque, which minimizes slippage and fines generation. Slow-speed DDC-Sizers are selected for the specific material and lump size to be crushed. Tooth profile selection allows the material to be grabbed and pulled into the crushing zone for maximum efficiency.
DDC-Sizers rotating inward utilize hydraulically adjustable roll shafts to ensure the product gaps between rolls are maintained. Outward rotating DDC-Sizers utilize adjustable crushing combs to account for wear and keep the crushing setting to specification. On each machine, crushing rolls are fitted with easily replaceable segments, which allows for much faster changeout and lower downtime. Intermeshing combs ensure removal of contaminants such as clays that can build up on other types of crushers.
McLanahan offers many different roll designs, tooth configurations and material selections that are engineered to maximize a sizer’s efficiency and wear life and to minimize the cost of ownership.
Applications for DDC-Sizers
DDC-Sizers are typically used in applications where the material being crushed has natural fracture plains and lends itself to compression crushing rather than attrition crushing or impact crushing. Coal, salt and phosphates are very common applications where DDC-Sizers are specified. DDC-Sizers deliver excellent control on product size and consistency. They are also very well-suited to crushing applications where the product is found in high clay bands and requires liberation from the clay as well as size reduction.
Sizers are recommended for applications where a 4:1 ratio is required. However, due to the low profile and relatively small footprint, these DDC-Sizers are often nested to deliver multiple phases in a single flow.
- Low roll speeds ensure minimum dust and fines generation
- Direct mechanical drives
- Compact design with right angle gear reducers and smaller footprint allow for installation in low-headroom areas
- Product setting adjustability to make up for wear or change in product size requirements
- Interchangeable segments and sizing combs throughout the machine
- Rail-mounted to be rolled out from the feed stream to facilitate maintenance or tramp removal
- A variety of roll designs and tooth configurations are available based on a customer’s application needs
- Drive systems are available from globally recognized OEMs