Basics of jaw crushers

A fixed jaw plate mounted within the crusher main frame, and a movable jaw plate mounted to a jaw stock comprise the jaw crusher. On the insides of the jaw crusher, cheek plates serve as additional wear parts to protect the crusher mainframe. The two jaw plates are arranged in a V-shape, narrowing the space from top to bottom. The nip angle is the angle formed by the V.

An eccentric shaft passes through the top of the jaw stock and pivots around a toggle plate at the lower half of the jaw stock to produce an elliptical motion. This geometry converts the eccentric shaft’s rotary motion into a fore and aft motion at the bottom of the jaw plate, resulting in the crushing action. The material is then compressed between the two jaw plates, shrinking in size as it descends to the crushing chamber’s bottom. The material’s output size can be adjusted by adjusting the gap between the fixed and moving jaw plates. This is known as the closed side setting and is typically measured between the peak of one jaw plate and the trough of another.

Jaw crusher limitations

Jaw crushers typically produce less fine material than impact crushers. A jaw’s reduction ratio is approximately four to one, and a jaw crusher is commonly used as a primary crusher for initial size reduction or to produce non-spec material. However, fines are required to meet specific gradations and increase material compaction.

Single toggle jaw crushers bear the brunt of the primary crusher load in conjunction with other crushers and screens. Crusher trains are a grouping of several mobile crushing and screening plants that work together to produce a high volume of high-quality products. A typical configuration includes a primary jaw crusher, followed by an impact crusher, which feeds into an incline screen to separate the aggregate into several fractions.

Jaw crusher maintenance

To keep your jaw crusher performing optimally, following various maintenance routines and behaviours is crucial.

Keep Things Clean

  • Check the oil level regularly to ensure it is not contaminated.
  • When changing the oil, ensure you clean out any dirt before opening the reservoir to avoid contaminating the new oil.
  • Replace the oil filters and seals and clean the breather filters.
  • Clean the dirt and debris from the crusher surfaces at the end of the workday.

Maintain the daily upkeep

  • Inspect the jaw ties and cheek plates daily for wear and the bolts for tightness.
  • Check your closed side setting to ensure a consistent result.
  • Change your jaw ties on time. Wearing them down too much will affect their maximum utilisation.

Be aware of your feeding habits

  • Feed a mixture of coarse and fine material into your jaw crusher. Feeding sized material may cause excessive wear in just one area, reducing wear life.
  • Choke feed the crusher to maximise output and increase material reduction.
  • Avoid trickle feeding your jaw crusher as it will only wear the lower part of the jaw plates, and you will lose valuable wear life.
  • Avoid overfeeding the hopper to allow the grizzly section to remove fines before the crushing process.

Jaw crusher features

  • The welded main frame makes for easier on-site assembly.
  • Rotatable jaw plate ensures higher utilisation of wear liner.
  • The smaller than average nip angle results in effective nipping and crushing of materials in the presence of moisture.
  • Gap setting adjustment allows for easy adjustment through a hand-operated hydraulic arm.

Jaw crushers are suitable for various industries, including diamonds, iron ore, nickel, uranium, copper, platinum, gold, chrome, phosphate, and manganese.

Why choose IMS Engineering?

IMS Engineering offers a range of high-quality and reliable specialist solutions for crusher plants at competitive prices. Our complete range of solutions is manufactured and supplied by world-leading brands for guaranteed efficiency. This includes ETCL/Kawasaki single-toggle jaw crushers, cone crushers, gyratory crushers, impact crushers, grinding mills and vibrating screens. With more than 60 years of experience and partnering with leading brands of specialist equipment, IMS Engineering is an industry leader and the ideal partner for your comminution mining company.

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