Hi James,

You can get good quality air knife systems from a number of sources (web search will get you the major suppliers). If that is not possible, start with Martin Engineering at www.martin-eng.com.

Be warned, however, that there are two potential problems with that approach. The first is cost -- keeping an effective airflow can be expensive. The second is dust control -- the force of the air can cause the overcarry material to be blown to areas that are sensitive to dust (i.e. a containment structure will also be required).

An alternate method of freeing trapped material from belt cracks is to use a "belt-thumper", similar to that used with corrugated sidewall belts. These products beat the bottom cover of the belt just after the discharge and loosened material falls into the chute (a chute extension may be required). You can get information on these from the larger sidewall belt manufacturers, such as Beltwall (www.beltservice.com) or Metso (www.metso.com).

Good luck on your project. ■

Have seen air knives using compressed (plant) air. This is wasteful of energy. They seem to work if the air stream is directed into the head chute for instance where dust collection air is being extracted.

Try talking to Spraying Systems Co. www.spray.com.au or 1800 622 508 about their Windjet system which uses a side channel blower. Never used it but it looks worth a try.

Michael Reid. ■

Hello again James,

I had another thought on the matter. If the heat cracks are not too deep, you may consider sanding the belt (assuming that it is not too long) to the point were the cracks disappear.

Note that I am also assuming that you have the right cover rubber for the application. If not, you are better off replacing the belt with one rated for the duty (consult with your belt manufacturer) then spending money on a constant stream of air.

Also, you may want to talk with Eli-flex to see if they have a product that can take the heat your process requires. Their regular product is very effective in handling damaged cover rubber.

Again, good luck in finding a cost effective answer. ■