HOW LONG IS A STRING? Depends on how much you want to pay.

I thought you are an expert. ■

Hello Ash

The most common radius that I have used is 3000m

The tightest being 2000m. I believe others have gone even tighter.

What you have to check is that the belt going around the outside of the curve stays put on the outer wing roll and does not cause the belt to fold in towards the centre. This is especially the case if the belt has to negotiate a concave radius at the same time, and also if it can be exposed to strong gusts of wind.

The other thing is that you have to stop the belt de-training. For that we rely on calculated idler frame geometry. However, if the radius is too tight there is too much shell wear, so you have to be a bit careful there too.

So no real rule of thumb, as it is better to calculate each curved conveyor on its own merit. (After you have done a few, you do get a feel for it though)

Cheers

LSL Tekpro ■

There are a number of unpublished techniques that can allow for horizontal radii to be reduced to 1000m range with steel cord belts. There are cases where this is reduced futher.

For fabric belts, this number has been cut to <300m radii.

Then there are methods that can reduce steel cord belt radii to below 500m.

No Rule-of-Thumb. ■

Mr Bhatnagar,

I think the tightest radius on H curves has been achieved on the tunnel of Barceona Line 9, with a 230m radius over 120°.

The conveyor was 4.8km for phase I and further extended to 8 km during phase II.

The belt was a special high elasticity steel cord belt, 1000mm wide. (1500t/h)

Please note that the radius by itself is not the main challenge: a narrow belt is easier to handle and control. Also the key pint is for how long do you have this radius.

The combination of short radius, wide angle and wide belt is the real challenge.

I can send you a complete file on Barcelona line 9 if you wish.

Just forward request to the moderator.

Kind Regards

JP ■