This document discusses centrifugal filtration and presents concepts through diagrams and text. It describes elements of centrifugal filtration including radial force parallel to the filter face, influent and concentrate channels, and gradients that form during centrifugation. Coriolis, centrifugal, and Euler forces are examined, and it is noted these forces can alleviate filter caking, enhance flux, and reduce energy per unit flux. Design concepts are presented to increase efficiency by increasing the surface area to volume ratio and Coriolis acceleration.

1. Dynamic Environment
For
Centrifugal Filtration
CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
by
Hanif A. Bholat, Melvin W. Cook

2. CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
Elements of Centrifugal Filtration
Radial Force
Parallel to
Face of Filter
Optimum Filter Position*
*David S. Lycon, Ph.D. Thesis
Univ. of Victoria, B.C. 1999
Slide 2

3. CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
Elements of Centrifugal Filtration
Influent/Concentrate Channel
Influent Flow
Parallel to
Radial Force
Slide 3

4. CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
Elements of Centrifugal Filtration
Gradients During Centrifugation
Slide 4

5. CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
Elements of Centrifugal Filtration
Coriolis, Centrifugal, and Euler Effects
Slide 5
Only in a Centrifuge
Significant Reduction
In Caking Density
Sustained Flux

6. Unit Volume,
Unit Filter Surface Area,
Unit Flux
Elements of Centrifugal Filtration
Surface Area/Volume Ratio: 1
Coriolis Acceleration = 2ωv
Envisioned Laminar Layer
Slide 6
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© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook

7. CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
Reduced Volume,
Reduced Filter Surface Area,
Reduced Flux
Elements of Centrifugal Filtration
Surface Area/Volume Ratio: 1
Coriolis Acceleration = 2ωv
Envisioned Laminar Layer
Slide 7

8. CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
Elements of Centrifugal Filtration
Concentrate
Out of Centrifuge
Envisioned Laminar Layer
Slide 8

9. CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
Elements of Centrifugal Filtration
Centrifuge in Operation
Alleviate Filter Caking
Enhance Flux
Reduce Energy per Unit Flux
Coriolis, Centrifugal, and Euler Effects
Only in a Centrifuge
Slide 9

10. CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
Elements of Centrifugal Filtration
Slide 10
To Increase Efficiency

11. CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
Elements of Centrifugal Filtration
1/10 Unit Volume,
Unit Filter Surface Area,
Unit Flux
Surface Area/Volume Ratio: 10
Coriolis Acceleration = 2ω10v
Slide 11
Increase Coriolis Acceleration

12. CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
Elements of Centrifugal Filtration
Reduced Volume,
Reduced Filter Surface Area,
Reduced Flux
To Increase Acceleration
Slide 12
Surface Area/Volume Ratio: 10
Coriolis Acceleration = 2ω10v
Concentrate
Out of Centrifuge

13. Elements of Centrifugal Filtration
Additional Alleviation in Filter Caking
Additional Enhancement in Flux
Additional Reduction in Energy per Unit Flux
Effects of Increased Coriolis Acceleration
Slide 13
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© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook

14. Coriolis, Centrifugal, and Euler Forces
The Blue Curve represents the action of a non-permeable particle moving away from the filter.
The Black Arrows represent the Coriolis Force, which acts perpendicular to the path of the particle
represented by the Blue Curve.
The Green Arrows represent the Centrifugal Force, whose line of action passes through the center
of rotation.
The Orange Arrows represent the Euler Force, which acts in the circumferential direction, and is
perpendicular to the Centrifugal Force.
Flux
Only in a Centrifuge
Slide 14
Fc = mω2/r
Ac = 2ωv Ef = ωv
Face of Filter
Parallel to Radial Force
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© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook

15. Proof of Concept Design
Slide 15
Filter Assembly
Influent
Clockwise Rotation
Top View – Cross Section
Scale 2:1
Filtrate Channel
Influent/Concentrate Channel
Filtrate
Conc
CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook

16. Centrifugal Reverse Osmosis
Slide 16
(With RO Cartridges)
Clockwise Rotation
David S. Lycon, Ph.D. Thesis
Univ. of Victoria, B.C. 1999
7% Reduction in Flux
After 5 Days
CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook

17. Proof of Concept Design
Slide 17
Filter Assembly
Influent
Clockwise Rotation
Top View – Cross Section
Scale 2:1
Filtrate Channel
Influent/Concentrate Channel
Filtrate
Conc
CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook

18. CONFIDENTIAL
© Copyright 2013, All Rights Reserved, Hanif A. Bholat, Melvin W. Cook
Only In A Centrifuge
Can
Coriolis, Centrifugal, and Euler Forces
Alleviate Filter Caking
Produce A Sustained Flux
Reduce Energy Consumption