Crumb rubber particles are normally covered with talc or another acceptable surface agent to prevent them from agglomerating. During pneumatic conveying talc (or any other surface coating) comes off even at a the low velocities of dense phase. Once the coating has gone away, dense phase conveying becomes impractical because the crumbs join each other and form solid plugs, without any permeability.

It is possible to dilute phase convey crumb rubber provided a lump breaker and a rotary valve are used to feed the crumbs into the conveying line and a large size dust collector is used to collect talc at the discharge end. In addition a special "bin discharger" type bin will be required at the receiving end.

Regards,

Amrit Agarwal

Consulting Engineer

Pneuamtic Conveying Consulting

Email: polypcc@aol.com

Ph and Fax: 304 346 5125 ■

Dear Mister,

the group Zeppelin certainly do this, please if your location is USA, give a call to Mr. Christian Tittensor.

He is the responsible for rubber business in all America.

His telephone number is +1 610 5335061. E-mail: motan@epix.net.

Or you may send your phone number and I ask him to be in contact.

We have a high range of solutions for dense phase conveying. Turboflow, Overflow, pressure pot, pressure pot with rotary valve. We show lots of alternatives, you choose the one that better conforts you.

Thank you very much. ■

The group Zeppelin is a German company located in Friedrichshafen.

I thought you were from the USA. If you are from Germany, you should contact our responsible in Zeppelin.

His e-mail is guido.veit@zeppelin.com

Thank you again ■

Reply that I have given above is based on my actual test runs at the test labs of competitors of Zeppelin. Without the talc coating rubber crumbs are tacky and under the dense phase pressure they stick to each other and form solid plugs, especially in vertical lines. Tests were run with all of conveying air at the pick-up point and also with split flow, i.e., both primary and secondary air using what is called the booster method. My conclusion is that dense phase conveying for rubber crumbs is not practical.

Regards,

Amrit Agarwal

Consulting Engineer

Pneumatic Conveying Consulting

Email: polypcc@aol.com

Ph and Fax: 304 346 5125 ■

Mr. Argawal,

Honestly I did not expect to meet a such well known profissional as you are.

Good to know you are so close to the subject of conveying system. Your article certainly shows your intimacy with dilute phase conveying.

I am wondering (and anxious) how it will be with the dense phase article.

Once more, I am at your availability if you need me.

Thank you. ■