I'm not one of the experts but there is a term in power calculation on aceelerating the fed material to belt speed. At least that term would increase more than two times. But i don't think it would have a giant effect.

I don't what else could happen, and i would like to learn, as well. Thanks for an interesting question. ■

Can you offer a sketch of the orientation and height between belts, and some detail of the product:

Some problems with counterflow feed:

1. Belt wear and puncture potential - much higher product turbulence in changing direction - can more than double belt wear rate

2. Extra power draw, for short belts this can be a major component of energy consumption

3. Potential of chute pluggage with the stagnation of mass flow and consequential build-up between skirts and into chute - highly depends on product properties and tonngage

4. Entrapment of product under skirt and liners scarring belt leading to leakage at scar and causing spillage from carryback in scar at discharge ■

The energy to accelerate material at the loading zone can be very significant.

For the prior posting today, "Maximum Belt Sag and Shaft Diameter" I sited an example of the influence of belt sag critieria. Using this example:

1. Total power draw is about 15.5 kW

2. Power draw from acceleration material and skirt drag is about 5 kW

2. Power to accelerate material along is about 4.5 kW.

Thus, about 25% of power is used to bring material to speed in this example. This is not insignificant when you consider all the in-plant conveyors with poor chute designs. Doing a little survey can demonstrate major payback with a little change in geometry and liner selection is chutes. ■

There is a need for a lot more information but the some issues that could occur;

> Excessive belt wear is very likely as the material will boil and have to be re-accelerated by surface friction and this always translates to excessive belt wear.

> If the belt is inclined then you will get a great deal of spillage over the tail pulley (in fact I have seen many tail pulleys buried due to this)

> Material spillage particularly if you design the conveyor at say 70% or more capacity and there is no skirt design systemn that will rectify this. In fact containing the spillage using skirts will see excessive wear along the skirt lines on the belt.

> As others have said, you will need more power.

Overall you are creating a maintenance nightmare, there must be some way around doing this.

Cheers

Colin Benjamin

Gulf Conveyor Systems Pty Ltd

colin.benjamin@gcsm.com.au

www.conveyorsystemstechnology.com ■

Dear Experts,

I feel the above all comments are much valid for flat / troughing conveyors. But opposite feeding is advantageous if the conveyor is a steep angle conveyor and conveyor takes off immediately after receiving.

Request your comments.

Regards, ■