Re: Horizontal Curves - Belt Modulus
Be cautious. THere arer many parameters that are still a mystery. No width, tonnage, temperature, idler trough angle, idler spacing, roll details, belt covers, drive power and locations, takeup type, etc. are given. Some added conditions are:
1. If you do not have the capacity to analyze curling and buckling then I suggest you get help. The curve magnitude with respect to belt ( assumed steel cord ) strength, width and modulus may no be compatible.
2. The starting or stopping tensions may produce an unacceptable shift or lateral displacement.
3. I note your location might be the UK. If so, then cold weather may also be a problem that cannot be evaluated in an accurate manner be catalog or CEMA or DIN ...... means. Most rubber compounds draw significantly more power below -5C and peak at -25 to -35C.
4. You may have another delema in spillage. How will you predict the behavior of the material in the tight turns and large banking angles as it moves into the curve or away from the curve?
All this and more should be known and integrated into your solution. ■
Re: Horizontal Curves - Belt Modulus
Thanks for the information.
I am fairly confident on points 2 to 4 you raised, it is the curling and buckling point that interests me. If the conveyors were using typically 1000/4 ply belting that the tensions require I would have no concerns on correct operation. The conveyors are generally 1 to 2 km long handling 300 TPH aggregates at 1.6 m/sec. The client is interested in using a second hand steelcord ST1250 belt they have available. My first instinct is too say no, but I'd like to give a more technical answer, plus now I've started thinking about the problem I can't put it down.
Are there any published papers, articles, etc. on curling and buckling, effects of modulus in curves. ■
Re: Horizontal Curves - Belt Modulus
Hello there..
In my computer model which I set up to design the horizontal curves curves, I put in a loud beep to warn me if the inner belt buckled and a loud string of beeps if the belt going round the outside lifts off the outer roll.
The most recent set of belts that I designed have co-incidentally used ST1250 and are 1050mm wide.
I remember that my computer did alot of beeping at anything less than 2200m radius. The conveyors varied in length from 1270m to 7500m long, and most use 3000m horizontal radius.
Personally, I would not go less than 2700m radius.
(I remember however that Graham Shortt was involved with one with a very tight horizontal radius, but as I recall, they ended up putting additional rolls on the inside, but I can't remember what belt width and type were)
Anyway, in my opinion, I would not attempt a 600 to 1000m horizontal radius on a St1250 belt whatever width it is. I prefer a good un-interupted night's sleep you know..
Regards
LSL Tekpro ■
Horizontal Curves - Belt Modulus
I have been succesfully designing curved conveyors using low powers and ply belting using balance of forces but have now been asked to look at a conveyor using some second hand ST1250 belting (selected by price and availabilty not strength) and fairly tight radii (600 to 1000 m), I have calculated that these curves are possible by balance of forces but am worried what effect the stiffness of the belting will have.
Can any one provide advice or references.
Thanks ■