Surface capture and depth capture are different concepts
A surface screen primarily retains particles at or near its face. A depth medium presents a tortuous network of fibres and pores, allowing particles to be retained within its thickness. This can provide useful solids-holding capacity in clarification duties where a thin surface layer might block quickly.
Depth behaviour does not mean every particle above a single stated size is retained. Real performance is influenced by the distribution of pore paths, particle characteristics, fluid properties and operating conditions.
Media properties that matter
Relevant media characteristics can include fibre composition, thickness, basis weight, porosity, wet and dry strength, flow behaviour and chemical compatibility. Activated-carbon media introduces adsorption considerations in addition to particulate retention, so its suitability must be established for the intended process.
Process conditions change the result
Build an application profile
- Fluid identity and relevant chemistry
- Temperature, viscosity and pressure
- Solids type and expected loading
- Target clarity or downstream requirement
- Filter equipment, dimensions and available area
- Cleaning, sanitation and documentation needs
Throughput and clarity can move in opposite directions. A tighter grade may improve particulate removal but increase resistance or shorten a cycle. Selection is therefore an engineering balance, not a search for the smallest nominal number.
Use representative trials
Bench or production trials under representative conditions provide stronger evidence than a specification considered in isolation. Record initial and final pressure, flow, volume processed, temperature, cycle time and observed filtrate result. Compare results against agreed acceptance criteria.
For product-specific information, use the filtration division’s filter-pad selection guidance or discuss the duty through its technical enquiry route.