2 ply belt problems

Posted in: , on 10. Apr. 2003 - 14:03

We have a 2 ply PN 150 belt which breaks at the splice where the strength of the 2 ply belt is reduced by half. The solution may be in trying a 4 ply PN 75 or a 3 ply PN 100. The belt is 400 mm wide. Any suggestions or comment would be appreciated. Is there such a belt manufactured and available?

Robbin Wood
(not verified)

2-Ply Belt Problems

Posted on 10. Apr. 2003 - 02:44

Have you ever considered using solid-steel belting with butt-welded joints. The entire conveyor must be designed to handle these belts, but if you want a heavy-duty conveyor material that will last several generations, then check out our website at 'www.processsystems.sandvik.com'.

It will definitely cost you more than everyday conveyors, but then again, everyday conveyors don't always work! Do they?

Belt Splice

Posted on 11. Apr. 2003 - 08:58

Check with Belle Banne Flexco near Sydney. I believe the gentlemen's name is Matt. They have mechanical splices that should work. These will not reduce the strength of your belt. Most of them are stronger than the belt but the belt will still break at its top limit.

Re: 2 Ply Belt Problems

Posted on 12. Apr. 2003 - 08:25


A lot depends on your system parameters and the way the belt has been spliced. Instead of changing the designed belt, you may be well served to have a belt service expert look at it.

Since you are in Australia, I suggest that you contact Bruce Baker via his www.mining-services.com website for consultation via e-mail (or connect directly to his e-mail via the member directory on this website). He has a wealth of experience and could advise you on what to look for.


Dave Miller ADM Consulting 10668 Newbury Ave., N.W., Uniontown, Ohio 44685 USA Tel: 001 330 265 5881 FAX: 001 330 494 1704 E-mail: admconsulting@cs.com

Re: 2 Ply Belt Problems

Posted on 14. Apr. 2003 - 02:47

It seems you have multiply synthetic fabric belt. In the event of belt replacement you can think of :

1) Reduced ply belt. It is 2 ply belt but with thick rubber between ply. This allows 100% belt strength at vulcanising joint.

2) 3 ply belt instead of 2 ply (i.e. 300/3 instead of 300/2). However please see that it remains troughabale.

Presently as suggested by K Finnegan & Dave Miller, please take advice of belt joint services. Also, reduce starting factor of drive (if possible) and it may help. This you can do by using soft start or fluid coupling.


Ishwar G Mulani

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

Email : parimul@pn2.vsnl.net.in

Re: 2 Ply Belt Problems

Posted on 15. Apr. 2003 - 03:12

Dear Sir,

Your observation on the reduction of the splice strength is correct. However, for this 2-ply belt you can add a bridge fabric that gives 100 % static strength over the top ply that is not contacted by the drive pulley.

You don't need extra plys.

We are specialist in splice designs for fabric and steel cord belts. See our website for an introduction.

Lawrence Nordell


email: nordell@conveyor-dynamics.com

Lawrence Nordell Conveyor Dynamics, Inc. website, email & phone contacts: www.conveyor-dynamics.com nordell@conveyor-dynamics.com phone: USA 360-671-2200 fax: USA 360-671-8450

Re: 2 Ply Belt Problems

Posted on 16. Apr. 2003 - 07:29

Dear Glenn Segers,

Further to my earlier comments. Following are the additional probable remedies :

1) Whether drive pulley is rubber lagged or bare. If it is bare, you can make it rubber lagged which will enable to reduce maximum tension and consequent joint failure.

2) Increase wrap-angle at drive pulley and reduce belt tension.

3) If it is screw tale-up, use hydraulic tensioner (tool) to set the tension (i.e. take-up pulley location) to impart required minimum tension. This can reduce the maximum tension and possible joint failure.

All above issues needs calculation / advice from belt conveyor designer.


Ishwar G Mulani.

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

Email : parimul@pn2.vsnl.net.in

2 Ply Belt Problems

Posted on 17. Apr. 2003 - 09:32

Dear Glenn !

One interesting alternative is to use the "Super-Screw-fastener". Formed like an “H”, the “Super-Screw fastener” has the same consistence as the conveyor belts themselves. With a multiply synthetic textile structure and rubber as cover material, the “Super-Screw“ meets the requirements of abrasion resistance and tensile strength you need (up to 100 % of the belt strength depending of the textile strength of the fastener!).

You will install this new flexible fastener by placing the belt between the top and bottom of the fastener and fixing them with self taping screws and a good power screw-driver with Prozidriv bit’s. Metal pieces inside the Super-Screw held the screws in position.

Like a hot splice "Super-Screw fasteners" has no hinge. There is no possibility for conveyed material to sift through the splice. Unlike traditional metalic fasteners, the “Super-Screw” is compatible with scrapers by skiving the top belt cover, to limit the fasteners over thickness on the belt and by installing it bias.

If you want further information about this solution you should contact :

BDT Senior Thermal Engineering Pty Ltd

Mr Gerard Grant

Mr Ben Lewis

66 Victoria Street

Smithfield NSW 2164

Tel 61 2 9604 2222

Fax 61 2 0604 7611

e.mail gerardg@bdteng.com.au