Dear Mr. G P Conley,

Possibly, this topic has been discussed earlier. Some points are as below for use of aluminum shell rollers for belt conveyors.

1) Aluminum tube will be thicker compared to steel tube. So, weight saving will not be in direct proportion to density.

2) Present day steel tube rollers have steel sheet housing welded to steel tube ends to form water-proof and strong construction.

3) Rollers of aluminum tube, will need cast iron or cast aluminum housing, press fitted and ‘dimpled’ at aluminum tube end. So this will again reduce saving in weight.

4) I have used aluminum shell rollers in some conveyors, however, their area of application / preference is not so large.

5) Fertilizer plants in India often use PVC tube rollers when corrosion is an issue.

6) Aluminum rollers with rubber lagging are extensively used in India, for conveyor zone near magnetic separators.

7) Aluminum shell will certainly have less life in wear. Generally, aluminum rollers are not used for conveyors of very high capacity conveyors (i.e. 750 mtph and above), and minerals of very high density and loading. So, possibly wear may not be a serious issue in the applications where aluminum rollers are likely to be used. Aluminum rollers cannot be a substitute for steel rollers, but will have its own area of application.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

G'Day GP,

I do not have data on wear life. I assume, abrasive and wet fine powder would yield a significant drop in shell life, in non-corrosive environment wrt steel shell or rubber covered rolls.

Fatigue would only be an issue if shell and end disk thickness were not sized for infinite fatigue life.

They are a lot more expensive, but in some installations (like salt water) they prove their worth.

Noise is reduced.

You might also consider other factors:

1. manufacturing tolerances with weld seam / roll run-out, el al

2. shell and end disk thickness requirements wrt steel

3. thermal expansion issues wrt to bearing grab with high thermal differentials

I believe Continental is flogging them in Oz.

Lawrence Nordell

Conveyor Dynamics, Inc. ■

I think that it all depends on the design and application.

There are aluminum extrusions for idler applications that provide the rigidity of steel and at the same time provide for mounting of the end caps that also can be made from aluminum.

The main issue is the cost. However in agressive environment applications, designs with stub shafting, meaning four bearings per idler, can provide very cost competitive solutions.



Antonio Reis

Vitrom Mfg Consultants

Your Process and Manufacturing Solutions

Phone: 209.834.1900

Fax: 209.834.1039

www.vitrom.com ■

I wonder does your interest in aluminium idlers extend to plastic idlers? If so, I can provide you with the contact details of a local supplier of these if you'd like to give me a call. ■