Dear Mr.Ali Ghane,

To reply you properly I need lot of information from you. Some of them are:

- Profile of conveyor.

- Distance of tail pulley from loading point.

- Materials to be handled & its physical properties.

-Drive location.

-The level difference as one way it would be down hill.

-Will it be regenerative? Why reversal is required?

Total picture I want, to reply you.

Regards.

A.Banerjee ■

Dear Ali,

Yes. You can use a reversible belt to transport 400 t/h up hill and then downhill on a 250 m long flight. Some caveats include:

1. loading points have to be vertically movable to allow passage of the product to discharge

2. the slope is angle allows incline transport

3. braking system takes into account

a) slope product stability,

b) brake system must act as holdback,

c) brake system must integrate with drive motor control to start and stop the bi-directional travels.

4. god design practice is followed for both flow directions such as the counterweight type, location and force including whether you can easily drive with it on the high and low tension side

5. drive should be located at the tail station eliminating maintenance issues

6. belt is selected to meet points 3,4 and 5

7. there are more points - let others make those comments.

Do not understand your comment about product load distribution. ■

Dear Mr. Ali Ghane Ms., P. Eng.

Reversible inclined conveyor is possible.

Inclination of say 2 degrees (sin inv of 0.03), is as good as horizontal conveyor. It seems you are referring to steeper inclination. The complexity in the design will increase with the increase of inclination. Generally, people avoid this kind of complexities.

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 ■

Dear A Ghane

250 m long inclined reversible conveyor is feasible . Mr nordell have already explained most of the points to be considered.

In my openion you should go for one drive at head and other on tail end.

A R SINGH ■

Dear Mr. Nordell,

For our knowledge can you clarify the following.

1.How braking system is used as hold back for a reversible conveyor.

2.For this type of problem we do not know the lump size & declination of conveyor.How you have come to a conclusion.

Regards.

A.Banerjee ■

Dear Mr Singh,

Can you realise the problem? Why drive on tail & head end? Have you checked the problem with an imaginary conveyor profile?Please think.

Regards.

A.Banerjee ■

DEAR Banarjee

I realise the problem drive on tail & head end is considered to reduce tension and belt rating. you pl do the analysis of imaginary conveyor you will find the results yourself.

How you can think of hold back on reversible conveyor, hold back function is to prevent reversal motion of conveyor. when conveyor is reversible hold back canot be provided.

in this case brake will act as hold back as when power supply is not there to motot brake will prevent conveyor motion in any of the direction

A R SINGH ■

Dear Mr. Singh,

I am not happy to your reply. Tell me, where I have written that I will use hold back in a Reversible conveyor.OK, forget it.

Just think that lump size is 200mm, declination is 30 M . If this be the condition, then what will be your reply.This is one example & it may be many. So please think.

Refer point no.3b) of Mr.Nordell reply.I wanted some clarification from him in this respect only.

Regards.

A.Banerjee ■

Mr. Banerjee:

You seem to have most answers to the queries of this forum. So, to save me unnecessary effort, be specific with the point you do not understand with respect to using a brake for a holdback on a reversible conveyor. Is the mystery instrumentation, logic, or mechanical design?

Application of a brake, acting as a holdback, is common practice. Hundreds of installations have used such a method in the coal fields in Germany and other locations around the world. WE do not recommend the practice, except for installations where a holdback cannot be used, such as suggested by Mr. Singh. ■

Dear Mr Banarjee

You have written "How braking system is used as hold back for a reversible conveyor" . It is my mistake i misunderstood .

Regarding lump size in my openion is iIrrelevant to the power calculation method and is important only for belt width and inclination selection

A R SINGH ■

Hello all..

The simplest way to convey in both directions on an incline conveyor is to turn it into a dual carry conveyor.

You simply put the downhill material on the return belt.

You can then use the holdback for the uphill and the brake for the down hill.

Put the take-up at the tail and the drive at the top and away you go..

LSL Tekpro ■

Dear Gram,

Although you might make something work, the cost and space penalties would make it very unattractive. ■

Hi Larry..

I don't really think it is a question of making it work, as it has been done before.

It is the same theory as for man-riding conveyors, of which I have done eight conveyors already, as well as my soon to be 7.5km long dual carry conveyor in Namakwaland.

There is a good example in Germany of a huge incline/decline dual carry conveyor which also works OK, so for a little 250m long conveyor, it should be as easy as pie.

You only need a couple of extra pulleys on the return belt, and a good knowledge of conveyor dynamics.

Cheers Larry..

LSL Tekpro ■

Bucket wheel on boom stacker-cum-reclaimer boom conveyor, will often have brake acting as a holdback. So, use of brake for holdback purpose is not uncommon. This will require certain measures so that full torque of the brake system should not get applied when conveyor is decelerating, when dealing with longer conveyors. So, for longer conveyors, it is rarely adopted because it will need different value of braking torque during deceleration and when the speed becomes nearly zero. Everything is possible but people prefer to do with least complexities. However, it is to be adopted when there is no option.

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 ■

Graham,

You missed my point. THe belt is too short and the dual load/unload zones too big to make a cost effective design accounting for the head room requirements between feed and receiving belts. Your are talking about big structures and the terminals. THese structures will consume at minimum 4m of additional head room and about 40m in elevated length.

As you know, we have designed up to 7km bi-way conveyors and many reversible systems, at ship loading ports, to make the claim for experience supporting the recommendation. ■

Hi Larry.. et al

We are currently designing two low level feeding points for the bottom strand of a dual carry conveyor.

We will simply load the return belt with vibrating feeders, which raises the top belt only fractionally.

Discharge is via a low level tripper on the return belt.

250m is a bit short though I suppose, but the dual carry in Richards bay at Indian Ocean Fertilizers is not that much longer and is a great success.

Regards

LSL Tekpro ■

Dear Sir

DUAL CARRY CONVEYOR OR ORDINARY REVERSIBLE CONVEYOR BOTH ARE FEASIBLE. TYPE OF CONVEYOR CAN BE DECIDED BASED ON ACTUAL REQUIREMENT ONLY.

BASED ON REQUIREMENT IN CASE DUAL CARRY CONVEYOR IS REQUIRED THEN WE HAVE TO PROVIDE EVEN LENGTH IS LESS THAN 250 M.

IT IS NOT NECESSARY TO PROVIDE HIGHER HEAD ROOM BETWEEN AT RETURN SIDE LOADING POINT AS SAME CAN BE REDUCED BY FEEDING BY VIBRATING FEEDER OR SCREW CONVEYOR OR ANY OTHER METHOD AS REQUIRED BY LAYOUT REQUIREMENT

SIMILARLY IN CASE DUAL CARRY IS NOT REQUIRED THAN REVERSIBLE INCLINED CONVEYOR IS TO BE PROVIDED.

IN SHORT IN MATERIAL HANDLING SO MANY COMBINATIONS ARE FEASIBLE FOR GOOD DESIGNER

A R SINGH ■

Dear all..

If you really wanted to be fancy you could put in a dual carry conveyor with a swop over (Pretzel) in the middle using compounded horizontal and vertical curves.

In this way you feed both strands on the return belt, and by the time each belt strand reaches the other end, they are both on the top so the material discharges normally over the terminal pulleys in both directions at the same time.

For a high tension "Pretzel" at 197kN I needed 198m to do this, so for a short 250m conveyor, We would even have the luxury of 50m of straight section at each end.

(Not much point if you only want to carry material in any one direction at any one time though)

LSL Tekpro ■

Dear Mr Bhattacharya..

For this conveyor it is drive at head, and gravity or winch take-up at tail for reversible or dual carry.

For incline conveyors, always try and control the slack side tension at the point of lowest tension, ie at the tail.

This also caters for when the conveyor trips out.

Regards

LSL Tekpro ■

Dear Sirs,

It is known to every body that brake is used as hlod back when there is no option.Mr.Ali wants a reversible conveyor using 400t/hr capacity on one side only. This is the problem. Why dual carrying conveyor comming in question?Dual carrying conveyor is generally unidirectional.I think this is a divercification of Mr.Ali"s problem.

As such incline reversible ( regenerative)conveyor needs special design consideration in respect of take-up, skirt,belt selection..etc..& for which one must know the profile & other things.

Regards.

A.Banerjee ■

Dear Sirs,

Please go through the subject matter & reply accordingly.Otherwise we are very confused.The problem is releated to inclined reversible conveyor only.

Best regards.

A.Banerjee ■

Hello Biplab,

I think you are giving due thought on this problem.Good , carry on.You are correct.

A.Banerjee ■

Dear all..

With regret, I give up on this one.. either you have done it before or you haven't done it before.

Those who have not should not try and dictate to those who have.

LSL Tekpro ■