Reliable slurry handling for aggregate applications

KREBS knife gate valves feature field-replaceable wear sleeves that extend past the valve body to provide superior sealing whilst eliminating downstream leakage. The bi-directional design handles flow in either direction with equal effectiveness, and the self-flushing action removes the need for packing glands that require constant adjustment and maintenance. Heavy-duty wear sleeves protect valve components from abrasive slurries, and the interchangeable actuator design allows valves to be reconfigured for different control requirements as plant processes evolve. Material is automatically ejected from the bottom during actuation, ensuring full gate closure and providing a reliable bubble-tight seal even with challenging slurries.

Cyclone diameter selection depends on required throughput capacity, target separation size, feed solids concentration, and available feed pressure. Larger-diameter cyclones process higher volumetric flow rates but produce coarser separation cuts, whilst smaller-diameter cyclones achieve finer separations at lower capacities. For sand recovery from classifier overflow in aggregates plants, 250-400mm diameter cyclones are typically specified.

Thanks to its improved separation efficiency and higher capacity per unit, you generally require fewer gMAX cyclones to achieve optimal performance than with conventional designs. 

Roping occurs when the cyclone underflow discharges as a concentrated central cord rather than dispersing in an umbrella or spray pattern. This condition indicates excessive feed density, insufficient feed pressure, or a blocked apex opening, all of which prevent proper classification. Roping reduces separation efficiency because material short-circuits through the cyclone without adequate residence time for classification.

Prevention requires maintaining proper feed pressure (typically 50-100 kPa above the minimum operating threshold), monitoring feed density to stay within design parameters, and regularly inspecting the apex for partial blockages caused by coarse particles or debris. The CycloStack device helps prevent roping by automatically adjusting the effective apex diameter in response to varying feed conditions.

Pumps operating near BEP exhibit stable discharge pressure, smooth vibration-free operation, and predictable wear patterns on impeller and liners. In contrast, operating significantly away from the BEP causes increased recirculation, excessive vibration, accelerated wear, and higher power consumption per unit flow.

Key strategies for determining whether a pump is operating at its BEP include monitoring power draw relative to flow rate, tracking wear-part life compared to expected service intervals, and observing bearing temperatures that rise when pumps operate far from BEP. FLS site support engineers use pressure gauges, flow meters, and power monitoring to verify operating points against published pump curves.

The externally adjustable wear ring on KREBS pumps allows the BEP operating point to be restored as components wear, maintaining efficiency throughout the service interval rather than accepting degraded performance.

Increased vibration levels indicate bearing wear or an impeller imbalance caused by uneven liner deterioration. Rising power consumption at constant flow suggests recirculation losses due to excessive wear-ring clearances or impeller wear. Decreased discharge pressure or flow rate shows hydraulic performance degradation requiring wear part replacement. Unusual noises, such as grinding or rattling, may point to component contact or loose fasteners. Seal leakage increases as expeller wear progresses.