Fine-Grinding Sizers

In response to customer demands, McLanahan has developed a small-footprint Fine-Grinding Direct Drive Crushing Sizer. This is the latest in the McLanahan range of DDC-Sizers, which offer a cost-effective alternative to high pressure grinding machines. McLanahan’s DDC-Sizer offers a twin drive, adjustable sizer using either fixed coupling or fluid coupling.

Fine-Grinding DDC-Sizers offer a very small footprint and low-profile design that allows wheel mounting or fixed support configuration. They are ideal for pilot plants or for small capacity applications such as lithium, cadmium, uranium coal and agglomerated ores.

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Why McLanahan Fine-Grinding Sizers

Mining operations around the world rely on McLanahan's experience and DDC-Sizers to crush their material to product size. McLanahan DDC-Sizers are designed to be more efficient and facilitate an ease of maintenance, with interchangeable sizing combs and segments throughout, as well as readily available gearboxes, couplings and motors. All DDC-Sizers are backed by McLanahan's service and support for the life of the machine.

How Fine Grinding Sizers Work

The Fine-Grinding DDC-Sizer frame is a welded and machined structure of heavy-duty design and construction suitable for lower capacity raw material in a tertiary or quaternary application. The frame is designed to house two parallel shafts and crushing rolls through heavy-duty bearing arrangements. The DDC-Sizer shafts rotate inward at a constant speed depending on the application and are reversible for the removal of debris.

Large diameter crushing rolls provide a suitable feed angle so that material falls directly into the crushing zone. The rolls have been designed to be adjustable, accommodating for wear. Wear liners are symmetrical, bolted in place for easy replacement, and made from abrasion-resistant material. Each roll shaft is driven by a heavy-duty drive assembly consisting of a motor, coupling and gear reducer fixed directly to the drive shafts. Stub shafts are bolted to single piece roll shells, which can be fitted with crushing segments, beaded using hard facing electrodes or left smooth depending on product size required. Top plates can be unbolted to allow entire rolls to be removed and replaced efficiently.

Popular Applications for Fine Grinding Sizers

Fine-Grinding DDC-Sizers are typically used in applications where the material is required to be crushed to small product size but without the fines generation or high pressure that is normally associated with other forms of comminution. Fine-Grinding DDC-Sizers are also excellent machines for use in pilot plants, and are very popular in processing battery minerals such as lithium. Other applications include agglomerated iron ore, phosphates and heavy metals extraction.

DDC-Sizers deliver excellent control on product size and consistency. DDC-Sizers 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.

Double Roll Sizers are recommended for applications requiring a 4:1 ratio of reduction. However, due to the low profile and relatively small footprint, these DDC-Sizers are often nested to deliver multiple phases of crushing in a single flow.

Benefits of McLanahan Fine Grinding Sizers

  • Generates minimum fines and dust
  • Higher torque and greater control offered with the direct mechanical drives
  • Can be installed in low headroom applications
  • Adjustable product setting to accommodate changes in product size requirements
  • Crushing rolls have large diameters
  • Crushing rolls are easy to access and remove
  • A wide range of crushing rolls and teeth configurations to match the customer's applications
  • Drive systems available from globally recognized Original Equipment Manufacturers

Frequently Asked Questions

Can I adjust the machine to account for wear?

Roll adjustment is a key feature of the McLanahan DDC-Sizer. As a center sizer, both roll shafts can be adjusted forward or backward to help maintain the required crushing settings. Hardface welding can be used to build up or maintain the roll profile on some types of sizer teeth. Worn teeth will quickly reduce the throughput capacity of your sizer. Worn teeth will also suffer accelerated wear as the tooth height reduces, so it is important to monitor and maintain your sizer teeth.

Why is even feed distribution important?

Controlling the flow of feed material into a DDC-Sizer is important to ensure an even distribution across the length of the rolls and to ensure an even split between them. Even feed distribution ensures even wear of the rolls, maximizing the life of the wear parts and the throughput capacity of the sizer. 

How/when do I grease the gear reducer shaft seals?

Gear reducers have one input shaft seal and two output shaft seals. These should be greased once per week. Add enough grease that any old grease is pushed out via the grease vent.

How do I take an oil sample and change the oil on the gearbox?

To facilitate easy oil sampling, the gear reducers on DDC-Sizers are outfitted with a sample valve on the oil drain port. 

To change the oil in the gear reducer, remove the top inspection cover and inspect the internal components for wear, damage or debris. Replace the desiccant filter/breather when changing the oil. This may need to be changed sooner if the desiccant beads turn red, indicating moisture saturation. Fill the gear reducer with the appropriate oil to the fill level indicated on the sight glass. Filling the gearbox with the correct oil and keeping the gearbox clean and maintained is key to long gearbox life.

How do I replace worn segments?

Worn segments can be replaced by first removing the threaded plug from the body of the segment so you can screw in the lifting eyebolt. Next, remove all the hex headed holding bolts from the segment. Finally, using a chain block, lift the segment vertically.