Compression LEP
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Description
The PMI Compression Liquid Extrusion Porosimeter (LEP) has the unique ability to measure pore volume and pore diameter while keeping the sample under compressive stress. The instrument is employed for characterization of porous materials used in many industries such as biotech, pharmaceutical, food, and environment. It produces no harmful effects on personnel or environment.
Principles of Operation
The sample is placed on a membrane in the sample chamber. The membrane is such that its largest pore is smaller than the smallest pore to be tested. The pores of the sample and the membrane are filled with a wetting liquid. Pressure on the inner piston rod is set to apply desired compressive stress on the sample. The outer piston rod is activated to apply desired pressure on the o-rings. The inner piston rod is activated to apply desired compressive stress on the sample. The pressure of a nonreacting gas is increased on the sample to extrude the liquid from the 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 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 of the sample.
Features
- Automatic application of compressive stress on the sample
- Any desired compressive stress up to 1000 psi may be selected
- Without dismantling the sample chamber, the pore structure of the same sample can be measured as a function of compressive stress
- Fully automated operation with a minimum of operator involvement
- One instrument performs like two: Measures liquid permeability like a permeameter, and pore volume like a Mercury Intrusion Porosimeter
- No toxic material (like mercury) is used - no health hazards & no disposal related costs
Specifications
For more information see our Compression LEP brochure, Liquid Extrusion Brochure, Porosimeter Brochure, and Characterization of Pore Structure Brochure.