Thread: Longest span possible for trestles

1. Longest span possible for trestles

What can be longest span possible for pipe conveyor carrying 4000 TPH coal? The total length being around 500 m.

2. Originally Posted by jps1272
What can be longest span possible for pipe conveyor carrying 4000 TPH coal? The total length being around 500 m.
That is a very very vague question and not likely to be answered without knowing all the details of the conveyor system design.

The only answer I can give you is the limit is based on the strength of the design. You can theoretically span as far as you want if it is designed correctly. But the longer you go the greater the challenge and the size of the components.

3. coal etc.

Originally Posted by jps1272
What can be longest span possible for pipe conveyor carrying 4000 TPH coal? The total length being around 500 m.
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As Gary said your question is general and a pipe conveyor if that size and
tonnage of 67 tons per minute will require more than a passing glance of the
type you have offered.

Have you even seriously examined a stationary rail car mover with a static unit train
set of 100-200 one hundred ton coal hopper cars (a 100-200 car rake) for the same work using a rack
drive electric locomotive such as the electric Stadler He 4/4 with a strub cog drive system?

It would need less infrastructure with concrete railways trestles cast in place with railroad bridge sections
between the trestles using cog track panels for the Strub COG track system and a Car Hoe would quickly
unload a belly dump hopper car in all weather conditions with a set of hopper car vibrators.

The Stadler He 4/4 electric locomotives have been operating around the clock seven days a week in Brazil
for the MRS Logistica folks since 2012 and they have at least 12-14 of them operating moving iron ore
down a 104% ramp to the harbor of Sao Paulo, Brazil.

4. span.. or how far to go

Dear Mr. Shah,

as you mention the total length to be 500 m, your meaning of span must be another than the total distance of transportation, as such.

Do you mean the distance between the pipe supporting frames?
A rough guess would be 1.5 to 2 m, t. b. clarified in design

Do you mean the distance of supporting trestles ??? under the conveyor bridge?
This question cannot be answered as such, as it really depends ... etc. etc. ... However, the Golden Gate bridge needs two...

Regards
R.

5. Dear Sir
This is purely a structural design issue,
If you mean longest span between the supporting trestles of the pipe conveyor then it depends the structure of the pipe conveyor.
When considering the normal box configuration of the pipe conveyor each pipe size has a maximum span dia 200mm can be 15-16 meters dia 300mm can be around 20-22 meters dia 400mm can be around 30-34 meters. Structures can also be made structurally stronger with deeper and wider sections and even installed in a full structural bridge.
But this is only rough guide each situation must have structural design check depending on height from ground, wind conditions seismic conditions etc.

6. span of gallery

Dear Shah
we have provided 58 m span gallery for pipe conveyor . As you increase span of gallery ,depth of gallery girder and member sizes increases . In case conveyor is having horizontal curve then it will be difficult to provide bigger span .
A R SINGH

7. Dear Sirs
We too have installed 50m span as a gallery for installing pipe conveyor within this is like structural bridge it is not possible to span this length with normal pipe conveyor structural box size configuration which as I understand is the meaning of the original question.

8. 90% Structural...at least.

Better late than never.
Fire safety regulations often demand provision for evacuation of a gallery at intervals of 50m whether the fire fighting is by hose or sprinkler. Evacuation is the governing criteria and this is routinely forgotten by conveyor designers. If the conveyor stands alone, no walkways, in open air then the thing can possibly be allowed to burn to ashes depending on environmental consideration. As mentioned earlier the issue is purely structural. Are you in the process of building a ceiling to protect the all enclosing conveyor from uv attack?

9. Originally Posted by johngateley
Better late than never.
Fire safety regulations often demand provision for evacuation of a gallery at intervals of 50m whether the fire fighting is by hose or sprinkler. Evacuation is the governing criteria and this is routinely forgotten by conveyor designers. If the conveyor stands alone, no walkways, in open air then the thing can possibly be allowed to burn to ashes depending on environmental consideration. As mentioned earlier the issue is purely structural. Are you in the process of building a ceiling to protect the all enclosing conveyor from uv attack?
The standard for long pipe conveyor gantries (i.e. where the normal pipe conveyor box could not be self supported) would be an open structural bridge with the pipe conveyor box with lighter structure installed with walkways either one side or both sides. The pipe conveyor itself would (certainly in UK) have mesh guards for inspection visibility and usually solid top cover. Aithough it is possible to totally for UV protection this is not normally necessary, ozone resistant belts can be obtained giving the cover of the belt a life at least as good as its mechanical properties.

In all well managed projects a risk and general assessment will be made to decide on access for evacuation on complex sites this could include other options but generally a ladder at a trestle every 50/100m or so depending on the location or perameters. There are many cases with spans greater than 50m by necessity i.e. over rivers, roads, railways etc and are assessed in the best way possible.

10. Hello,

Your information implies that you have pipe conveyor of 4000 mtph capacity and 500 m conveying length. Also this is elevated conveyor and is installed on gantry trestles. Your question is what could be the longest possible span for the gantry? (i.e. longest spacing between trestles)

Such structure is designed such that it becomes most economical duly considering the specific restrictions / hurdles (if any) for trestles. For structure to be economical, it should have least (minimum) tonnage as total of gantry + trestles. This is a routine job for structure designers. You may discuss with them.

In a particular configuration, one will find that total tonnage becomes more if trestles are too close, or even when trestles have excessive spacing.

In general if gantry is at a lesser height, then one will find that comparatively lesser spacing of trestles make the work economical. Contrary if gantry is at a great height, then comparatively longer spacing of trestles, make the structure economical.

If you wish to have no trestle come what may, then structure designer will be also happy to do such work. In News some time we see bridge crossing the river without any pillars (trestles).

Ishwar G. Mulani
Author of Book: ‘Engineering Science And Application Design For Belt Conveyors’. Conveyor design basis is ISO (thereby book is helpful to design conveyors as per national standards of most of the countries across world). New print Nov., 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