You must first answer how short a stopping time is acceptable, what type of belt you will use, and how you design the chute to regulate the ore acceleration onto the conveyor in question.

To construct a conveyor with a 1.0% grade and apply a CEMA type of calculation could have a very long or unacceptable coast time to stop. There are many dependencies such as idler details, counterweight, drive system, etc. ■

The real criteria other than stopping in a reasonable time is how fast will you allow the belt to accelerate, during its drift, before it begins to decelerate as material is discharged off the belt. The operating temperature could also have a large effect. The age of the conveyor will change the stopping characteristics.

In short, there is no easy or simple answer when prudent engineering is applied.

A 6% grade will see the belt increase in speed to a unacceptable level (> 3 times its operating speed), with damage to drive assemble from overspeeding, before it begins to decelerate. Even at 3% you will likely have > 2 times increase in belt speed during the drift to stop. ■

Hello Hermes..

Without a regenerative system, the frictional resistance of the conveyor will have to be greater than the regenerative head available.

The latter is related to the tension in the belt, which in turn is related to the mass per metre on the belt... so...

What I am getting at is that if you design for a full belt with lots of sag, it can work at up to about minus 2.5 degrees, but at lower capacities it could run away, and only slow down at even lower capacities where the regenerative head becomes low enough.

In any event, the answer to your question is no at 6 degrees and dodgy even at 2.5 degrees..

Cheers

LSL Tekpro ■

Assume the conveyor stops periodically. Reasonable?

Assume there is material on the stopped conveyor. Reasonable?

Assume that alpha degrees decline is the same as alpha degrees incline. Reasonable?

Consider that if the material isn't correct for going up alpha then it certainly won't be correct for coming down alpha.

Examine the starting and braking conditions and recognise that the sag modifies your envisaged decline.

Then fit a brake anyway, as advised previously. ■

Louispanjang...

I don't know what you have been smoking, but I am sure it would be far too strong for me, in my ageing sheltered existance..

What are you tying to say?

LSL Tekpro ■

Dear All:

anyone has some experience for soft brake system? same as soft start of conveyor system, that means the brake system can stop the conveyor graduallly. please note that i am not seeking for park brake.

thanks ■

Yes, we have designed many (100's) downhill and undulating belt conveyors that require complex, large, accurate, fail-safe brakes with self-healing properties -- if components, sensors, or logic cause some degree of malfunction.

Hydraulic fail-safe proportion-integral-derivative variable band-width control is one type of soft-start-stop integrated control.

We also do premptive digital fail-safe controls with both hydraulic and pneumatic circuits.

We have designed the world's largest belt conveyor brakes as measured by torque and caliper-disk heat load.

We license technology to brake component and system suppliers. ■

Dear Sir:

the brake should be flame proof, that means the brale heating should be not exceed the undground reqiurements. ■