Filtration Resistance: Separate Medium and Cake Contributions

Define the Interface or Transport Basis

NPTEL lecture 36 on filtration principles separates the pressure drop through cake from that through filter medium. In a simple Darcy-type series-resistance model, flux J=deltaP/[mu(Rm+Rc)], with medium resistance Rm, cake resistance Rc and filtrate viscosity mu. Keep this chosen model explicit.

Review a Hypothetical Comparison

Assign hypothetical medium resistance 2×10¹⁰ m⁻¹ and cake resistance 8×10¹⁰ m⁻¹. The total is 1×10¹¹ m⁻¹, with the medium accounting for 20% of that sum. At viscosity 0.001 Pa·s and pressure difference 100000 Pa, modeled flux is 0.001 m/s. Treating all measured resistance as cake would overassign its contribution; treating a clean-medium value as unchanged after exposure would also require evidence.

Keep the Evidence with the Decision

Keep a clean-medium reference and the basis for estimating deposited-material resistance. State what other contributions the model neglects. Record viscosity at the same state and use flux per area rather than silently substituting total volume flow. When the medium clogs or its properties change, distinguish the exposed-medium result from its original clean reference.

This invented partition supports a model review, not a filter selection or observed performance claim. A total pressure-flow result alone cannot uniquely identify every physical resistance contribution.

Does the pressure-flow model identify the clean medium and deposited solids separately?

This blank worksheet is for your own project. It contains no H M machine trial result.

Customer Questions

Primary References

These references support the technical principles discussed in this guide. The worked examples and review questions are educational.

• NPTEL lecture 36 on filtration principles
• Reference from hmpharmamachines.com