Bulk density

Bulk density is the mass per unit volume occupied by a granular material, whether in powder or granule form, taking into account the voids between individual particles. Unlike true density (the density of the pure solid material), bulk density depends on the shape, size, and particle size distribution of the particles, as well as on how the measuring container is filled. This parameter is of fundamental importance in the plastics industry for managing storage, transport, and dosing processes: knowing the volumetric occupancy of a resin or powdered compound allows for the proper sizing of silos, hoppers, gravimetric feeders, and pneumatic conveying systems. It is also an indirect indicator of material quality, as variations in bulk density between batches can signal irregularities in the particle size distribution or moisture content of the product.