Hi there..

For steep angle I assume you mean pocket belt, which is essentially a flat belt cross stablalised with stuff vulcanised on to contain the load.

The cross stabliser has its warp and weft reversed to give it rigidity across the width

If you were to do this with steelcords it would not be easy, as steelcords generally are pre-ensioned and run in the warp direction, i.e. in the direction of the belt. (Some rip-stops use this though, and Kleber of Paris started doing this in the early 80's...very expensive)

It is however very easy to ask the mill to weave you a synthetic carcass with the EP warp at ninety degrees to the belt direction and a stretchy highly crimped nylon weft in the direction of the belt.

Put one ply on top of the cords and another on the bottom, and you have a belt that is rigid sideways, but flexible longitudinally.

Regards

LSL Tekpro ■

Take care in applying cross stabilizers. The addition of a weave or cord across the belt over and under the tension member will increase the transverse stiffness. Increased transverse stiffness can have the added benefits noted, but can also have negative consequences.

The belt will be more difficult to trough. It will be more difficult to align and maintain good tracking.

The increased stiffness will act like a transverse spring and apply more local idler roll pressure, which in turn will require more power to operate the conveyor. We have witnessed > 15% increase in operating power due to the increased rolling resistance on a large/log overland steel cord belt. ■

Larry..

The fabric ply on a steelcord belt is for impact protection and for rip protection.

One would not use a cross stabalising ply for this, and you simply revert back to the warp in the direction of the belt.

This gives a big crimp in the nylon weft, thus giving good stretch and troughability.

For this reason, the strengthening cross wires used by Kleber in their steelcord belts were specially designed to stretch about 15mm per 1000mm and I was easily able to stretch one by hand. After this amount of easy stretch, they pretty much reverted back to Young's modulus

The cross stabalising plies that I originally described are for pocket belts which require considerable latteral rigidity to enable pocket belts to go around bar-bell pulleys on the return route.

Sometimes even this is not enough, like what I believe predictably happened to the high rise pocket belts at Essar Steel in India last year.

Have a good one

LSL Tekpro ■

Dear Graham,

Yes, I agree that the fabric ply placed above and maybe below the steel cords can be for impact and drip protection. Most often this is a full weft/warp fabric or a cross-fabric reinforcement.

I agree with Your term "cross stabilizing ply" which suggests that they are used as transforce reinforcement of flat belts such as pocket type.

However, not all high angle belts are pocket belts. Some may include trough belts for which I added the response.

The confusion I have is the second sentence of the first paragraph. The rip and impact protection "would not use a cross ply", only a warp strong weave. Maybe I do not understand your comment.

Generally, all trough belt cross facric reinforcements are for rip and impact protection. By example, observe the advertisements on Phoenix fabric cross ply in steel cord belts. This is one of many manufacturers. ■

Larry

For the fabric ply for rip and impact protection, the warp of the ply must be in the direction of the belt so as to allow the weft (which has a large crimp (i.e. like a sine wave) thus making it stretchy) to give tranverse flexibility.

I am aware of Phoenix's re-inforced belt.

We bought alot of it recently for Sishen Iron Ore Mine (SEP)

We are about to pull in a long 2.4m wide class 2500/5 "Phoenotec" for primary crushed iron ore.

My previous comments relate to pocket belts, as I understand that to be what A. Banerjee was enquiring about.

Cheers

LSL Tekpro ■

Dear Graham,

It is all a matter of deflection. There are belts that require protection of the tearing of rubber between the steel cords from large lump impact. The crimped weft may have too much give and thus allow the rubber to delaminate between adjacent cables. The weft must be designed to take up the deflection before the rubber fails. Such is the problem in the oil sands mines.

Cross reinforcement that protects against rip or acts as a rip stop should be strong enough to expell the ripping object. Thus, a stronger weft would be superior to a weaker weft. However, there is the problem of troughability, trainability, and power consumption.

Its all in the engineering. ■