Liquid Extrusion Porosimeter
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The PMI Liquid Extrusion Porosimeter is a unique instrument with the ability to measure through-pore volume, volume distribution and liquid permeability without using mercury. The instrument is employed for characterization of porous materials used in many industries, such as biotech, pharmaceutical, filtration, food and environment. It produces no harmful effects on personnel or the environment.
The sample is loaded in the sample chamber with a membrane under the sample. The membrane is such that its largest pore is smaller than the smallest pore one wishes to measure in the sample. The pores of the sample, the membrane, and the space below the membrane are spontaneously filled with a wetting liquid. The pressure of a nonreacting gas is increased on the sample to extrude the liquid from pores.
The differential pressure, p required to displace liquid from a pore is related its diameter, D, surface tension of the liquid, γ and contact angle of the liquid Θ.
The displaced liquid passes through the membrane and its volume is measured, while the membrane prevents the gas from passing through because of insufficient pressure. The gas pressure gives the pore diameter. The volume of displaced liquid gives the pore volume. Measurement of liquid flow rate without the membrane under the sample yields liquid permeability through the sample.
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The Liquid Extrusion Porosimeter is employed for the characterization of porous materials used in many industries, such as biotech, pharmaceutical, filtration, food and environmental, without fear of harmful effects on employees or the environment.
Applicable industries are:
Learn more about how the LEP evaluates complex pore structures.
For more information about applications please see our other technical papers.
- One instrument performs like two. Measures liquid permeability like a permeameter and pore volume like a mercury intrusion porosimeter
- No toxic material like mercury used. No health hazard. No disposal-related cost
- Fully automated. Simple to use. Very little operator involvement
- Highly reproducible and accurate
- A wide variety of samples can be investigated
- Pressure required almost an order of magnitude less than that required for mercury intrusion. Can be used for pressure sensitive materials
- Only instrument capable of measuring through-pore volume
- Effects of application environment measurable (stress, temperature, chemical environment)
- Capable of measuring very large pores (up to 1000 microns)