Plug Screw

• Feeding unit for stationary and circulating fluidized bed combustions.
• Feeding unit for gasification plants or grate firings.
• Feeding screw for waste wood, flakes, secondary fuels such as BRAM, fluff or plastic chips, paper sludge, municipal and industry sludge, coal, coal flotation and pond sludge, other compressible bulk materials.
• Feeding screw before digesters in the paper industry.
• Feeding screw before rotary furnaces in pyrolysis plants.
• Feeding screw to feed presses as pre-compressors.

The plug screw consists of:

• Screw case
• Feeding chute
• Cooling case
• Inlet and outlet for cooling water
• Screw shaft
• Bearing unit
• Drive unit
• Carriage to bring out the screw

The bulk material will be transferred to the plug screw from selected process silos with a metered discharge which transports the bulk material to the feeding point of the combustion plant. Material is compacting continuously inside the screw spiral.

The plug screw can be designed so that the compressed material inside the screw spiral will be loosened before inlet to the process, which can be an advantage (i. e. pyrolysis drum, drier units etc.).

Feeding stationary fluidized bed combustion chambers, the bulk material will be transported directly in the sand bed. Therefore light bulk materials like plastic chips, foil chips, paper etc. can be brought directly into the combustion zone and the retention time can be increased.

For grate firing systems, optimum usage of the grate can be achieved by the parallel arrangement of several plug screws. Therefore “blow-through” can be avoided and combustion optimised.