Deflectors and Rock Boxes for Smooth Material Flow
The transfer chute is typically designed to ensure full flow and a consistent material path. However, the flow of bulk material through the chute can vary due to changes in material properties, variations in tonnage, chute wear, or buildup of material on the chute walls.
Deflectors
Deflectors are often employed within transfer chutes to absorb impact and reduce wear, starting from the point where the material trajectory meets the head chute. It's crucial to maintain adequate clearance between deflectors and the head pulley of the discharging conveyor to prevent large lumps from obstructing passage or cohesive materials from sticking to the plate, which could lead to chute blockages.
Once the material flow departs from the initial contact point with the chute, fine-tuning the material flow during system startup may be necessary. Deflectors, also known as "kicker plates," are typically incorporated into the chute design from the outset or installed during startup to guide the material flow.
During the commissioning of a new conveyor system, it's common practice to install deflectors in the loading chute to assist in centering the load. Achieving the desired flow path through the chute often involves a process of trial and error. These deflector plates should be adjustable in the field to allow repositioning for optimal performance. Accessibility for efficient replacement and inspection points are critical for maintaining proper material deflection.
Deflectors installed on the inner surface of the loading chute can improve load placement by directing material lumps towards the center of the load zone, reducing the risk of them slipping off the belt edges or damaging skirtboard seals.
To mitigate issues related to off-center loading, deflector wear liners can be placed at the bottom of the loading chute next to the belt. These liners, featuring bends or angles, redirect material towards the center of the belt and away from its edges. However, caution is needed in their use to avoid problems like material entrapment and chute blockages. Popular methods for managing bulk material flow and minimizing impact include installing scalping bars or utilizing rock boxes.
Scalping or Grizzly Bars
Scalping bars, also referred to as grizzly bars, positioned within the transfer chute, allow fines to pass through first, forming a protective bed on the belt. Oversized lumps that cannot pass between the bars slide down the incline and land on the belt cushioned by previously deposited fines. Grizzlies function similarly to grates at truck dumps, preventing large lumps from entering conveyor systems. 
Rock Boxes
Rock boxes feature a ledge inside the drop chute where conveyed material accumulates, redirecting subsequent material flow or absorbing abrasive force. This setup reduces drop height and dissipates impact force as material bounces off the accumulated material on the ledge.
Rock ladders, consisting of baffles or miniature rock boxes, are used to control material velocity and reduce impact over longer drops. Typically arranged on alternating sides of the chute, rock ladder shelves ensure that material never free-falls more than 1.5 to 2 meters (5 to 6 ft).
Rock boxes and rock ladders are best suited for chutes handling materials such as sand, gravel, or hard rock, provided that physical conditions and flow rates remain stable. Careful consideration of material cohesion, especially in wet conditions, is essential to prevent accumulations that could block the chute. It's advisable not to use rock boxes in transfer points handling fragile materials prone to degradation or materials with large lumps that may obstruct flow. Similarly, they should be avoided if a conveyor system will handle multiple materials.