Dear SAM,

Density is defined as: mass/volume in kg/m3

Various densities can be defined by the way, the mass is taken in relation to the volume.

The mass of a material in bulk occupies a volume, which includes the material volume + the inter particle volume + the porous volume. (Bulk density)

The mass of a particle occupies a volume, which includes the material volume + the porous volume. (Particle density)

The mass of a solid material occupies a volume, which includes the material volume only. (Material density)

As long as the method of measuring the density is specified, any density is possible and acceptable.

have a nice day

Teus ■

Teus has given you the insight into the perceived interpretations of density. All that remains to be defined is the substance. Disturbance generally reduces density so the substance's history and future need to be known to identify the keyword 'substance'. But the instantaneous density is just as TT defines it. ■

Sam,

Bulk density is the weight (lb) of a bulk solid in one cu ft volume. Units can be lbs/cu ft or kgs/m3. It is determined by poring a bulk solid in a container of known volume and weighing the container before and after filling it with the bulk solid. Bulk density of a solid can vary somewhat depending upon the storage conditions. It can be as-pored bulk density, or settled bulk density, or compacted bulk density.

For bulk solids it is important to know their bulk density in order to design plants for handling and processing them. Let me give you an example. Suppose you have to design a storage bin for storing pelleted polyethylene (PE). You will have to know the bulk density of PE for this work. The real density (specific gravity) of PE is about 0.9 to 0.96 whereas its bulk density is about 30 to 36 lbs/cu ft. Bulk density, therefore, allows calculation of the storage bin volume.

Hope the above answers your question.

Regards,

Amrit Agarwal

Consulting Engineer

Pneumatic Conveying Consulting

Email: polypcc@aol.com

Ph and fax: 304 346 5125 ■

Thanks for ur info. ■