Porosity and pore size distribution of materials Method of evaluation by liquid expulsion

Available format(s)

Hardcopy , PDF

Language(s)

English

Published date

15-09-1993

Publisher

British Standards Institution

Committees responsible
Foreword
Method
   Introduction
1 Scope
2 Informative references
3 Definitions
4 Principle
5 Apparatus
6 Procedure
7 Calculation of results
8 Test report
Annex
A (informative) Examples of the calculation of maximum,
   minimum and mean flow pore diameters
Figures
1 Types of pore space
2 Simple form of typical manually controlled apparatus
3 Typical sample holder
4 Typical plot of flow rate against pressure for wet
   and dry runs, performed on a single test sample
5 Example of plot of wet and dry runs from maximum to
   minimum pore sizes
6 Cumulative flow pore size distribution
7 Differential flow pore size distribution
List of references

Describes evaluation of pore size characteristics by application of gas pressure causing expulsion of liquid filled pores.

This Part of BS 7591 describes the evaluation of pore size characteristics (such as mean, maximum and the distribution of pore sizes) that allow the flow of liquid from one side of the wetted structure to the other. It is a comparative and usually non-destructive test. Pore size is commonly expressed as `pore diameter\'. The pore diameter is calculated from the applied gas pressure, which causes the liquid filled pores to be emptied, resulting in a flow of gas through the sample.

The method is suitable for the study of through-pore materials, such as filter paper, paper, polymer membrane filters and cloth. It enables pore sizes to be estimated within the general size range of about 50 mm down to about 0.05 µm.

The test involves the application of pressures up to 1 MPa²⁾ (150 psi). For most materials this pressure does not cause compaction or deformation of the material which would result in a change in the pore structure.

The technique should be considered to be comparative, as for most porous media a theory is not available to allow an absolute calculation of pore size.

It is the recommended method for the evaluation of filter papers (see BS 6410).

²⁾ 1 Pa = 1 N/m².

Committee	LBI/37
DevelopmentNote	Supersedes 92/76154 DC (10/2005) Reviewed and confirmed by BSI, November 2012. (10/2012)
DocumentType	Standard
Pages	14
PublisherName	British Standards Institution
Status	Current
Supersedes	92/76154 DC : JUN 92