Dear Banarjee

I am not sure about avantages of full/half trough depths .

Some designers keep the head pulley in line with top line of idlers, this is called full trough depth.

Some designers keep the head pulley top at the Half depth of material cosssection above idlers . this is known as half trough.

By keeping head pulley top at half the matrial trough we get following advantages

1.0 Transition length of the conveyor is less

2.0 Conveyors capacity is selected based on idler crossection . In transition portion Designed Troghing angle is not avalable and in case of lower transitin portion chancesof material spreding and spillageare less

3.0 In half trogh at head end material turbulance is less as at head pulley matrial is bought to avearage height



At tail end half trough lDepth is practiced only in case of less transition space available.

A R SINGH ■

Hello Banerjee..

I never use half trough depth for the following reasons:

- At the discharge end the geometry messes up the trajectory calculation, and the material always seems to land in the wrong place.

- At the feed end, the belt doesn't seem to sit nicely in the trough, and usually rubs hard up against the feed chute.

As a result I always set the terminal pulleys at one third trough depth, (unless I need to be able to drain water off the tail that has a horizontal loading section)

I calculate the transition lengths accordingly.

Cheers

LSL Tekpro ■

Dear sir

I have not observed much change in discharge geometry due to half trough but didnot found any reason why At the discharge end the geometry messes up the trajectory calculation

A R SINGH ■

Dear Mr A R Singh..

Would you like me to recommend you to a good optician?

Or are you just trying to boost your own ego?

How can you comment on something that you have not experienced? This is not good for the cross flow of experiences and information within our very fine forum. Like Larry and others, I take this forum seriously and spend valuable time on it. Suggest you do the same.

LSL Tekpro ■

While a half trough design does show in the CEMA standards and has been used in the conveyor industry, I do not recommend it at the tail pulley for the following reasons:

1. The half trough design configuation does not allow the belt to immediatley rest fully in the idler trough after leaving the first full idler.

2. Trying to seal this configuration with dust seals or any kind of transfer point sealing equipment is extremely difficult because the belt line does not remain stable.

3. In the unloaded condition the belt rides above the center idler for a distance. When loaded the belt becomes fulley troughed.

These items make sealing the load zone much more difficult than needs to be. There are instances however when there is not enough room to provide the proper transition distance for the belt being used. In this case, I would then design the load zone with a gradual transition the full length of the load zone using adjustable idlers, belt support systems if required, and sealing systems. ■

Dear Mr Spring

I donot like to give and receive such comments in this forum. I have expressed my views why At the discharge end the geometry messes up the trajectory calculation .you mean to say trajectory calculation cannot be performed with half trough.

I can also suggest go to optician and see Wether with half trough belt fouls with chute or skirt

A R SINGH ■

Mr Singh..

It is not my prerogative to waste the forums time (and my time for that matter) by granting you a full reply to your remarks, as you either do not understand, or have had insufficient experience within the wide and important realms of the pitfalls of transition geometry.

Larry G on the other hand obviously has had experience and has addressed some of it above. I suggest you read his imput if you unable to accommodate and comprehend mine. In any event kindly refrain from misleading and lowering the quality of the forum.

LSL Tekpro ■

Dear Shri Banerjee,

The issue you are referring is raising the terminal pulley level to reduce the transition distance. In this context my comments are as below :

1) In case of textile fabric belt, the transition distances are not so large. If the space permits, one can avoid the raising of the terminal pulley level. I have used raising of the pulley very sparingly in number of projects where I was concerned.

2) For the steel cord belt, transition distances are quite large. Here, people often opt for raising the pulley level. The steel cord belt weight is also more and this also facilitates the raising of pulley level.

Whenever the terminal pulley level is raised, it should be checked for the required transition distance and also for the stability of belt i.e. belt should remain on idlers in varied operating situation, particularly during continuous running.

Regards,

Ishwar G Mulani.

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

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■