dear fgaona,

The aquired velocity of the pellets represent kinetic energy, which has to be absorbed by the pellets when they collide against the wall or amongst themselves.

This collission energy damages and possibly heats the pellets.

Therefore the velocity in the pipeline is a key parameter in case of particle detoriation.

As you already corrected the pipeline for stepped pipe lines, you must be aware of the occuring velocities.

Are the velocities high enough for conveying, but not too high in relation to damaging the pellets ?

(This question has to be answered for every pipe section)

good luck

teus ■

You mention stepped pipes and Gamma bends but you didn't mention internal pipe surface treatment. Is there any?

What grade of Polymer are you running?

Is there an air cooler on the air supply discharge?

Do you have a layout of the pipe geometry?

We have performed many analyses to address the various issues with plastic pellets.

The solution is seldom just one element but more often correcting / modifying several areas. ■

Dear Fgaona,

My experience is that broken plastic pellets are mainly caused by poor design, construction, and operation of the pelletizing system, not in pneumatic conveying lines. During pneumatic conveying plastic pellets can wear out but seldom break-up. It all depends upon the rheology and brittleness of the plastic that you are handling. Most of the plastics are not brittle.

Regards,

Amrit Agarwal

Consulting Engineer

Pneumatic Conveying Consulting

Email: polypcc@aol.com

Ph and Fax: 304 346 5125 ■