6.1 SCREEN SELECTION TIPS
Successful screen application is dependent on experience rather than on precise mathematical formulas.
Wire cloth manufacturers have gathered a wealth of experience from compilation of data and research.
The primary function of screens is to separate particles into specific sizes. Separation is accomplished
by presenting particles to various size screen openings, applying vibration thus allowing material small-
er than the opening to fall through. To accomplish these screening objectives, there are a wide variety of
types of screening media.
A.
Application
There are two (2) major considerations that greatly effect screening production;
1. Proper screen combination (top / bottom) for the raw material.
2. Proper operator loader technique (See section 3.5).
The top screen deck is as critical to the screening operation as the bottom one is doing the final
sizing. When selecting a top screen, consideration must be given to the fact that it not only takes the
impact and abuse of the raw material, but it must feed the bottom screen deck at a particular rate. Just
how well the top deck feeds the bottom deck determines production efficiency.
B. Selection
Screen selection process starts with some basic questions;
What is the size of final product you wish to end up with. This will set the parameters for the size
of the bottom screen. If it does not have to be an exact size, then a slotted type screen is more efficient
for increasing production by lowering processing times.
Another condition to consider is the strength required of the screen. Smaller screen wire diameters
process material faster but wear out quicker and will not stand the abuse of large or heavy impacts. The
heavier the wire gauge, the smaller the hole opening is, slowing process times, but increases screen
longevity.
C. Tips
To get the longest wear life from the screen;
Keep the screen properly tensioned. See section 4.3A. The screens must be kept tight enough to
prevent unwanted movement between the shaker deck and screen material.
The screens should be rotated 180º occasionally to allow the wear to be shared evenly on both
ends of the screen.
For screen selection assistance, contact Thomas Equipment: 1-800-538-0187.
6. REPLACEMENT SCREENS
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