Trommels utilize _____________ surfaces to accomplish material screening?
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Answer: C. Punched plate
Explanation
Trommels commonly use perforated or punched metal plates wrapped in a cylindrical shape to screen and separate materials by size. Punched plate screens offer high structural rigidity and abrasion resistance when processing heavy rock feeds. Rotating the cylindrical drum causes smaller particles to fall through the perforations while oversize material exits the end. A trommel screen consists of a slightly inclined rotating perforated metal cylinder driven by an electric motor. Internal lifters or spiral flights can be incorporated inside the cylinder to advance material toward the discharge chute. Punched plate aperture sizes are easily customized with circular, square, or slotted hole patterns.
Option A is incorrect because fibrous cloth lacks the mechanical strength required for screening heavy bulk solids. Option B is wrong since woven wire screens stretch and deform rapidly under heavy tumbling rock loads. Option D is incorrect because punched plate is the correct standard screening surface utilized in trommels.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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