Dust removal from gas using wire mesh: Metallic wire mesh as a filtering medium for dust-laden gas is characteristic of which device?
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AAir filter (wire-mesh or metal-screen type)
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BBag filter (fabric dust collector)
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CVenturi scrubber
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DHydrocyclone
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EElectrostatic precipitator
Answer
Correct Answer: Air filter (wire-mesh or metal-screen type)
Explanation
Introduction / Context:Particulate removal technologies rely on different media and mechanisms. Wire-mesh screens are used in certain air filter elements (e.g., prefilters, oil-wetted screen filters) where the mesh provides impaction/impingement surfaces and structural rigidity for low-to-moderate dust loads.
Given Data / Assumptions:
- Gas-phase dust removal at relatively low pressure drop.
- Reusable or cleanable metal elements preferred.
Concept / Approach:Wire-mesh air filters capture particles by inertial impaction, interception, and sometimes with tackifier oils. Bag filters instead use fabric felts or woven textiles, not metal mesh, and rely on a dust cake for high efficiency. Venturi scrubbers are wet collectors; hydrocyclones are inertial separators without a porous medium; electrostatic precipitators use electric fields and plates/wires, not mesh as the primary medium. Therefore, a device explicitly using metallic mesh as the medium is an air filter of the wire-mesh type.
Step-by-Step Solution:
Match medium (metal mesh) to device type.Exclude devices that employ fabric, liquids, or fields instead.Select “Air filter (wire-mesh type).”Verification / Alternative check:HVAC/industrial prefilter catalogs list layered metal mesh filters for coarse dust and oil mist service.
Why Other Options Are Wrong:
- Bag filters: fabric media.
- Scrubbers/hydrocyclones/ESPs: different collection principles and media.
Common Pitfalls:Assuming all “filters” use fabric; metals are common for cleanable prefiltration and high-temperature service.
Final Answer:Air filter (wire-mesh or metal-screen type)