Hello,

Your supplier has already explained to you issues arising in pipe conveyor, due to thick / stiff belt (as per his construction). Now, after all the persuasion if he is reluctant to change his stand, then practically you have two options:

A) Accept his stand because he is responsible for guarantee and performance.

OR

B) Get alternative quotation if some reliable supplier comes out with cover of your choice.

And then you have to decide whom to rely on.

Imposing arbitrary choice on supplier will dilute his responsibility, and commercially counter productive as it may be somewhat risky for the buyer also. The views from forum or others may not alter this situation.

Ishwar G. Mulani

Author of Book: Engineering Science And Application Design For Belt Conveyors (new print November, 2012)

Author of Book: Belt Feeder Design And Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Pune, India.

Tel.: 0091 (0)20 25871916

Email: conveyor.ishwar.mulani@gmail.com

Website: www.conveyor.ishwarmulani.com ■

Again Mr Mulani is the voice of reason. It becomes a question of responsibility. Do YOU want to take responsibility for the belt selection or do you want your conveyor supplier to retain the responsibility for this choice ■

Belt thickness selection for pipe conveyor is very critical aspect as it can result in over drawing of power as well as increased friction. We have recently very bad experience of this.

The pipe conveyor belt supplied to us for handling coal @ 1800 TPH and 4.5 m/sec (by OEM) is EP 800 /5 against design recommendation (by OEM) of EP 800/4. Even after operating the belt on load for almost 4 weeks, the current drawn is almost double than it should be.

There is lot of argument now going on blaming belt thickness and belt stiffness.

Very unfortunately, before the resolution could be found by OEM for this, the tail pulley shaft got sheared. ■

"As per our client requirement belt cover shall be 7mm on top and 5mm on bottom. "

So, you, and a few respondents, are concerned about warranties and conflicting belt specs. Give the man what he asked for and let him carry on.

Pipe conveyors are not the panacea they are meant to be and no reliable Code of Practice exists after these things were developed in the 1970's by the Japanese Pipe Conveyor Co.

The specified bottom cover seems a bit thick. There is no mention of a change of carcass so if it can be assumed that there is no change then the radii of curvature differ by 2mm. If you know the drum diameter then it is possible to roughly work out the strain difference but that won't tell you much.

Material used to be conveyed quite comfortably on troughed belt conveyors and I am surprised at the readiness of Users to accept these unsound surround gadgets without considering the alternatives. Rubber cost is at least doubled (more in your case) and rollers must be provided to profile the return belt notwithstanding the extra price of rollers for the carrying strand itself. If your Client is hell bent on using a pipe conveyor then he probably accepts the arbitrary nature of belt life and power consumption. Ask him. ■

Originally Posted by ganesh3

we would like use Pipe Conveyor for transporting Calcined Petroleum Coke at material temp of 90 degree C. the belt width is 2200mm (Pipe dia 600mm) and length 1.2km.

As per our client requirement belt cover shall be 7mm on top and 5mm on bottom.

but our vendor is proposing belt cover 5mm on top and 3mm on bottom. Vendor explained that the for Pipe Conveyor System is the most critical aspect in terms of minimizing the operational problems. An under-designed belt may cause belt deformation while an over-designed belt can lead to excessive power consumption and damage to both belt and system. a too much thick cover could be damaged easier due the continuous open/close of the pipe (cover thicker more distance of external fibers from belt neutral axle higher tension on external fibers due to the belt transversal bending for open/close operation) and in addition to that, a thicker cover will determine an higher power consumption

I would like to know your opinion on Pipe Conveyor Belt Selection. is it acceptable (Vendor proposal) and does it affect belt life & operation??

Please advice.. Thank you in advance..

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Any answer must carry caveats. High temperature = 90C will reduce the integrity of both rubber and fabric. Both will have an increase in the polymer tan (Delta), which signifies a likely increase in polymer hysteresis = higher power draw. The increase in top and bottom cover may also increase this or it may not. The increase belt thickness may inhibit the belt structure from collapsing with belt tension and with span between idlers. A collapsed belt will certainly increase power draw. Without a full evaluation of belt properties, idler configuration and geometric profile, the belt cover answer must stay vague. There are test methods that will give a better understanding of an accurate answer to you question, but, it goes beyond the trivial answer. Raising the temperature of a full fabric and rubber belt sample to +90C and maintain it is also not trivial.

A sample of belt inner and outer cover can be analyzed and a orthotropic test procedure be introduced that can then indirectly provide an accurate answer, but, it will cost time and material. Best to get the engineering done by a competent party before the mistakes. ■

Originally Posted by jps1272

Belt thickness selection for pipe conveyor is very critical aspect as it can result in over drawing of power as well as increased friction. We have recently very bad experience of this.

The pipe conveyor belt supplied to us for handling coal @ 1800 TPH and 4.5 m/sec (by OEM) is EP 800 /5 against design recommendation (by OEM) of EP 800/4. Even after operating the belt on load for almost 4 weeks, the current drawn is almost double than it should be.

There is lot of argument now going on blaming belt thickness and belt stiffness.

Very unfortunately, before the resolution could be found by OEM for this, the tail pulley shaft got sheared.

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Dear Mr. Shaw:

I read your comment about excessive power draw with special interest. You claim a pipe conveyor belt supplier offered a EP-800/5 construction while a design recommendation by OEM was EP-800/4. I can believe both constructions can lead to excessive power draw if the underlining calculation method is flawed. As stated many times fabric construction will typically draw from 2-3 times more power than an equivalent steel cord construction. The reasoning has many parts. However, it is of special interest to us on what standard or method you used to expect to have half the power draw you found in the initial commissioning phase.

Basic numbers such as "DIN f" would be most helpful together with conveyor design. Noting complaints about performance without offering due-diligence data is not helpful and can lead to missing the cause-and-effect you seek. Share all data and get a reasoned answer in return. ■