There are many parameters to be considered. It would be important to know if the existing equipment you are to reuse was used originally for PE pellets or for another application.

The capacity and conveying distance would be necessary to determine, even in a preliminary form, if the equipment you have is capable of doing the new job.

The formation of streamers and fines is typically a concerrn when conveying pellets and if it is also a concern in your case, that would dictate the use of treated pipes and special bends.

Assuming the existing equipment consists of typical rotary airlocks and positive displacement blowers, the normal pick up velocity you would have to consider is 4200 feet per minute. ■

Dear Fernando,

I will be glad to help you without any fee. I have over 40 years of design, operating, and construction experience in all types of plastics, especially PE and PP. Send me complete information on your existing system for my analysis and recommendations.

Regards,

A. T. Agarwal

Consulting Engineer

Pneumatic Conveying Consulting Services

Emailolypcc@aol.com

Ph and Fax: 304 346 5125 ■

Generation of angel hair when dilute phase pneumatically conveying PE is avoided by using "scored", i.e., internally roughened pipelines. Roughening must cover the entire surface of the pipeline by a method called "shot blasting". Properly "scored" pipelines will almost completely prevent angel hair generation. If you need specifications for the pipe scoring method, please contact me.

Regards,

A. T. Agarwal

Consulting Engineer

Pneumatic Conveying Consulting Services LLC

Email: polypcc@aol.com

Ph and Fax: 304 346 5125 ■

The conveying line bends are also sources of angel hair generation.

Suggest you use short radius elbows in lieu of conventional long radius sweeps. Blinded tee bends or crosses also produce good results in this application. ■

I have had success using "scored" long radius bends, Hammertek bends, and Gamma bends to prevent angel hair. Stainless steel long radius bends are much better than aluminum long radius bends because aluminum wears out faster. Depending upon the number of bends, system pressure drop with short radius bends will be higher.

Regards,

A. T. Agarwal

Consulting Engineer

Pneumatic Conveying Consulting Services LLC

Email: polypcc@aol.com

Ph and Fax: 304 346 5125 ■

Agreed, there are several commercial types of bend configurations which have demonstrated success, many are actually alternative forms of standard short radius bends. As you mentioned, depending on the line configuration, they may also be subject to higher pressure drops. ■

You asked for references/books...I suggest:

(1) Pneumatic conveying of solids, klinzing, marcus, rizk, leung, Chapman and Hall, 2nd edition

(2) Dixon, G, Pneumatic Conveying, Plastics Pneumatic conveying and bulk Storage, Chapter 2, Applied Science Publishers, 1981

(3) EEUA Handbook

peterwypych@uow.edu.au ■