A crane system lifts the waste from the refuse pit and transports it to the feed chute, which consists of a hopper and chute. The feed rams push the waste from the feed chute onto the combustion grate. Due to the height of the waste column in the chute, folse air is unable to leak into the combustion system. Microwave level detectors report the height of the waste column in the chute to the crane operator. Bridging and obstructions are prevented by the inclined side walls of the hopper and the flaring of the chute. A shut-off damper located underneath the feed hopper is closed when the plant is not operating.
The feed ram changes the direction of waste flow from vertical to horizontal. The waste, compacted in the feed chute, is loosened during this process and pushed onto the grate in amounts determined by the combustion control system.
The transition between the feeder and grate is in most cases designed as a drop-off edge, but can also be built as a slope.
Each feed ram is driven by a hydraulic cylinder. The combustion control system prescribes cycle time, stroke length and stroke speed to achieve uniform combustion on the grate. Feed ram operation is staggered for combustion grates with several grate runs.