McLanahan | Tertiary Sizers

Tertiary Sizers

Tertiary Sizers can be used in surface and underground mining operations for the 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.


Unlike Primary and Secondary Sizers, which feature inward rotating rolls, the tertiary design features outward rotating rolls. This provides two crushed product streams in one machine and allows feed material that is already to size to pass through the openings between the rolls, minimizing additional fines from inter-particle crushing.

Tertiary Sizers are typically used in applications where the material being crushed lends itself to compression crushing rather than attrition crushing or impact crushing. Coal, salt, phosphate and other friable materials are very common applications where Sizers are specified. Sizers deliver excellent control on product size and consistency.

The standard ratio of reduction is 4:1; therefore, it is common in applications that require higher ratios of reduction to have multiple units running in series to accomplish the necessary reduction.

How McLanahan Tertiary Sizers work

Tertiary Sizers are compact direct drive crushers that feature low-speed outward-rotating rolls that accept a constant, controlled feed rate of material and size the feed against adjustable sizing combs. The material that is already to size can pass around the crushing zone, which helps in generating less fines.  

Why McLanahan Tertiary Sizers

McLanahan Tertiary 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. Equipped with hydraulic lift cylinders for ease of wheel activation and drive arrangements that are attached to the mainframe of the sizer, the unit can be rolled out from the feed stream to facilitate maintenance.

The Tertiary Sizer frame is a heavy-duty fabricated steel assembly with easily replaceable wear parts. The crushing rolls consist of interchangeable alloy steel segments bolted to a heavy-duty barrel. The shafts are supported through self-aligning double row spherical roller bearings.

The drive configuration consists of an electric motor, fluid coupling and gear reducer. A combination of underspeed sensors and fluid couplings protect the drives in the event the sizer encounters a stall condition.

Frequently Asked Questions About Tertiary Sizers

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You can check Tertiary Sizer tooth wear by measuring the height of the tooth from the base and comparing it to the as supplied tooth height. You can also use a tooth profile template to accomplish this.

To build up the tooth profile on some types of sizer teeth, consider hardface welding to increase throughput capacity.

With Tertiary Sizers, even feed distribution allows even wear across and along the rolls, maximizing the life of the wear parts as well as the capacity of the sizer.

Grease the Tertiary Sizer's gear reducer shaft seals once a week. Make sure you add enough grease that all old grease is purged from the seal.

McLanahan Tertiary Sizers are designed for ease of maintenance.

Features & Benefits
  • Minimum dust and fines generation
  • Can fit in low headroom areas
  • Provides a smaller footprint
  • Product setting size can be adjusted if requirements change
  • Interchangeable segments and sizing combs throughout the machine
  • Rail-mounted to be rolled out from the feed stream to facilitate maintenance or tramp removal
  • Replaceable/interchangeable crushing elements

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