Three tried-and-tested measures are used to prevent wet clay from sticking in the hopper of a mobile crusher: a 40 mm vibrating screen at the inlet, a 2 mm anti-adhesive coating, and two 50 Hz vibrators suitable for the crushers in operation.
After rain, hammer mills become clogged with damp limestone due to increased particle adhesion; the risk is higher when the moisture content is >12.8% and the screen gap is <18 mm. This can be reduced by drying, reducing the feed rate or increasing the rotor speed.
The rotors of rotary crushers used for crushing reinforced concrete tend to crack due to the non-uniformity of the raw material, a problem exacerbated by an incorrect rotor speed and large chunks of raw material; chromium-alloy steels and correct equipment settings are recommended.
After replacing the hammers in a rotary crusher, vibration occurs in 92% cases due to rotor imbalance, discrepancies in hammer mass, loosened fastenings or wear on the mounting seats; five parameters must be checked, and a single hammer must not be fitted in place of a pair.
During prolonged operation of the cone crusher, the oil temperature rises due to heat generated by friction components, a reduction in the cooler’s efficiency (it must be flushed every 6 months) and a decrease in the oil’s viscosity; the maximum permissible temperature is 85 °C.
When the supply of pebbles is consistent, overload in a cone crusher is caused by wear and tear on the crushing elements, incorrect clearance, a fault in the load sensor, or the moisture content of the pebbles; there are specified parameters to prevent malfunctions.
Wedge-shaped wear on the jaw plates of a crusher is caused by uneven pressure, asymmetrical movement of the jaw plates and varying levels of abrasiveness in different areas; whilst it cannot be eliminated, the rate of wear can be reduced by 30%.
When the gap width remains constant, the jaw crusher loses 12–27% of capacity due to wear on the jaws, misalignment of the moving jaw, and wear on the drive; the indicator reading does not reflect the actual condition.
A vibratory feeder is the best choice for a crusher processing large granite: chute width 1200+ mm, vibration amplitude 8–12 mm/16 Hz, liner thickness ≥20 mm, ribs spaced ≤400 mm apart, incline 12–15°; belt-type feeders are not suitable for pieces larger than 300 mm.
When selecting a mobile plant for processing asphalt concrete alongside a road, the following factors are taken into account: dimensions (width up to 2.55 m, turning circle up to 8 m), noise levels ≤75 dBA, emissions, set-up and dismantling speed, and compliance with regulations without the need for additional permits.
