Seed Production of Vegetable, Tuber and Spice Crops (2+1)

5. Friction Cleaning

• The air-screen combinations cannot remove debris that has a size and density similar to the seeds.
  
• However, if the debris has a different surface texture, it may be possible to remove by friction cleaning.
  
• Any object rolling or sliding over a sloping surface encounters a certain friction depending on the texture of itself and that of the sloping surface.
  
• Separation is made on a velvet cloth or rubber belt with variable inclination, which ensures that the slope necessary for the run off of the seed is different from the slope necessary for run -off of the debris.
  
• The belt continuously moves upwards and removes the debris while the seeds roll down the slope. (Fig. 6)




Figure 6: Working principle of friction cleaner