The yield of roller crusher in sand production is generally in the range of 85%-98%, which is significantly higher than that of vertical shaft impact crusher (60%-85%). The core mechanism of its high yield lies in:
1. Squeezing crushing principle: the laminar crushing force generated by the double rollers rotating in opposite directions makes the material uniformly subjected to force in the closed chamber. And the over-crushing rate is lower than that of the impact crusher by more than 50%.
2. Intelligent gap adjustment: Hydraulic/spring system can achieve 0.1mm precision control of roll pitch. Which ensures that the qualified rate of material size is increased to 98%.
3. Material adaptability: for medium-hard materials (compressive strength ≤ 160MPa) such as river pebbles. Limestone, etc., the yield can be stable at more than 90%; construction waste recycling field measured up to 95%.
Three major factors affecting the yield rate
Characteristics of raw materials
Hardness threshold: when the material Moh’s hardness>7 (such as granite), the yield will drop 8-12%. High chrome manganese steel rollers (3 times longer service life)
Moisture content control: raw material humidity>5%, sticky roller phenomenon leads to a sudden drop of 15% yield. Use a pre-drying or water-mist dusting system.
Equipment parameter configuration
Roller tooth design: Shaped rollers (non-equal round and non-engaging) increase the yield by 6% compared with the traditional round rollers, and reduce the risk of clogging.
Power matching principle: To process the construction waste output, the motor power needs to be increased by 20% compared with the traditional configuration.
Process optimisation
Pre-processing solution: raw material over 40 mm is first roughly crushed by the jawbreaker, increasing the final output by 10%.
Closed-loop design: 3-5 mm material is returned to the crushing process to increase the total output to the theoretical peak.
Three strategies to improve the yield
Strategy 1: Dynamic adjustment system
Installation of PLC intelligent control system, real-time monitoring of bearing temperature, roll pressure and other parameters, when the detection of a downward trend in the yield automatically adjust the roll pitch, compared with manual adjustment to improve the stability rate of 40%.
Strategy 2: Full life cycle management of wear parts
Adopting ‘hardness gradient’ roller skin technology, the hardness of the working layer reaches HRC62 or above, and the replacement cycle is extended from 3 months to 18 months, which avoids the decline of yield due to wear and tear (the monthly decline rate is <0.5%).
Strategy 3: Environmental protection and efficiency programme
Integrated pulse dust removal + negative pressure noise reduction module, in the case of an environmental protection sand plant in Zhengzhou, not only to meet the requirements of the environmental assessment (dust <15mg/m³), but also to increase the yield by 7% year-on-year.
