You have not told us anything regarding belt size, belt fabric thickness, belt weight per foot, distances between the belt transistion point and the tripper, distance from the tripper to the return transition point at the first pipe idler.

A tripper requires belt that is more flexible!!

Beside the fact that most trippers are required to move from point A to point B to fill a long bin unless you have a single dischage with a left and right dump at one location and only one location for dumping good luck! you need to be more forthcoming with information!

What or who possessed you to use a pipe belt for this application? ■

It might be possible but it certainly isn't desireable. To quote Designer's Irishism "If I wanted to get to there I wouldn't be starting from here."

While the belt opens the cereal will have time to spread around & when that thin film of cereals gets thrown off the tripper pulley it will need a thin & wide, can't get away from the Irishisms, wide across the belt line, collector. Wall slope angle will mean a high discharge point, which in turn will throw the belt power through the roof compared to what should be required. Out of the total conveyor length you will spend a considerable distance opening up before the tripper; wrapping the belt up again & then finally opening up the belt again.

I imagine the money could be better spent if you used a simple troughed belt & diverted the savings from a shorter intermediate canopy, cheaper belt & less drive machinery into providing high quality covers for the said cheaper belt.

Alternatively try Sicon if they're still around: they deserve to be. If the intermediate discharge is not sometimes required the Sicon can be closed up to provide continuos grain protection. Can you do that with the pipe conveyor? Of course you can't ■

Dear Sir

If you have a fixed tripper then it is possible to use a pipe conveyor especially if the conveyor is of considerable length the opening for the tripper can be similar to normal pipe conveyor opening i.e. fo a diameter 300mm pipe 7.5 - 8 meters and when the material is discharged the close again over 7.5 meters.

These sections can be enclosed, however the selection of the pipe conveyor should be made on other factor such as containment of the material and route i.e. curves etc of the conveyor.

Paul Holt

Dosco Overseas Eng Ltd. ■

Dear Sir

Further

Looking again at your specification.

Over 1.2 km the distance taken for opening and closing is very small.

For diameter 400mm, at the tail end 10m to close, at the intermediate disccharge 10-11m to open and 10m to close, then at the delivery end 10-11m to open.

Of course all systems have their benefits pros and cons but in my experience over this length of system a pipe pipe conveyor will always outway the Sicon system.

Paul Holt

Dosco Overseas Eng Ltd. ■

Dear Narflc

Sorry if the previous was not clear.

Of course a traditional conveyor is an option but from the previous a pipe conveyor is also an option with a fixed tripper you just need to open the belt for the tripper and then close again according to the perameters previously stated.

A Sicon although could do it would be a little more complex and as you say a relatively low capacity and also when such distances are involved in my opinion not so economic.

However where the conventional belt does score is when the tripper is movable, in this case it cannot be done sensibly with the Sicon or a pipe conveyor.

Paul Holt

Dosco Overseas Eng Ltd. ■

Dear Mr. Narflc,

So, your installation requirement is to have a pipe conveyor about 1 km of length. This pipe conveyor is to discharge into silos near head end zone and also somewhere in the middle zone. For this you intend to use tripper on this conveyor in the middle zone.

My general observations are as below :

1) The pipe conveyor pipe has to open out and to form a trough belt at the discharge end. So in this case you are changing pipe to trough profile prior to discharge pulley. So, this is routine / natural for pipe conveyor. Pipe also opens and closed at take-up.

2) The belt so opened out will be in trough profile, for some distance and then again you intend to convert into pipe form. This trough belt material carrying capability has to be equal or more than pipe portion of the conveyor. As per the analysis and general acceptance, the trough belt can carry more material than belt, for the same belt width, so on this issue you are also on safer side.

3) The main issue is whether your pipe conveyor is straight or curved in plan view. The middle zone has to be straight in plan view where the tripper would be travelling. So, if the pipe conveyor has horizontal curvature in vicinity of the tripper travel zone, then, you can have a problem about the stability of the belt.

Based on the serial no. 1 and 2, it appears that you can have a travelling tripper on this pipe conveyor in middle zone, if the pipe conveyor is straight from beginning to end. However if it is curved, then the issue becomes complicated. Please discuss with your supplier of the pipe conveyor and you will come to know the reason for suitability or unsuitability for such proposition. Notwithstanding what I have said, your pipe conveyor supplier’s recommendations prevail (my reply to you is in response of fifteen minutes effort for your query).

In general one should refrain from doing things when opinions are seriously differing.

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 ■