ARCHIVED TECH TIPS

There are many factors that contribute to the success and failure of pneumatic edge trim conveying systems. Here are some things to consider:

1. Volume of the air thru the system. The volume, measured in cubic feet per minute (CFM), must be sufficient to convey your edge trim to the collection point. Volume becomes a critical factor, often times, over long conveying lengths. It is important to calculate your volume and loss of volume over long distances for your system.
2. Pressure of the air thru the pneumatic trim conveying system. This includes suction pressure (negative pressure) and discharge pressure (positive pressure). Keep in mind that the maximum air flow thru any pneumatic conveying system is in the center of the duct. As you measure air flow toward the side of the duct the air flow (speed and volume) is less. Your trim may move out of the center of the duct and toward the duct inside diameter (ID) surface. This may be an effect of static or gravity. Trim may be impossible to convey, especially at high speeds when there is a lot of friction between it and the duct work. Higher pressure systems will keep edge trim away from duct ID and more in the air stream. Properly designed pneumatic edge trim systems will incorporate enough pressure (regardless of speed and volume of the air) to convey your edge trim at maximum machine running speed.
3. Speed of the air. As a very general rule of thumb, the air speed through your trim removal system should be at least double the speed of the trim at maximum machine running speed.
4. To chop or not to chop. Chopped edge trim is much easier to convey, especially long distances. You should consider chopping continuous edge trim when conveying waste long distances.

Always remember properly designed edge trim removal systems should handle all your edge trim at maximum machine running speed. You should never have to slow your production, so your edge trim system can "keep up".