Advanced Capillary Flow Porometer (Patented)
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Principles of Operation
A wetting liquid is allowed to spontaneously fill the pores in the sample and a nonreacting pressurized gas is allowed to displace the liquid from pores. The gas pressure and flow rates through wet and dry samples are accurately measured.
The gas pressure required to remove liquid from the pores and cause gas to flow is given by:
where D is the pore diameter, γ is the surface tension of liquid, θ is the contact angle of liquid, and p is the differential gas pressure. From measured gas pressure and flow rates, the pore throat diameters, pore size distribution, and gas permeability are calculated.
Unique Features
- No need to undo the sample chamber assembly for wetting the sample
- Considerable reduction of test time
- The sample is not disturbed during wetting
- Exactly the same area is tested
- Results are more accurate and reproducible
- The sample chamber at the bottomof the piston rod contains o-rings on the outside (circumfrence) to prevent leak between the insert and the sample housing of the sample chamber
- The sample chamber prevents sidewise leak through thick samples because of circumfrential o-rings
- Inserts with different opening sizes allow different sized samples to be tested
- The need for cutting samples for testing is eliminated with the use of spacers so that damage of the test material is eliminated and test time is further reduced
Capabilities
- Diameter of the most constricted part of a through pore (pore throat)
- Bubble Point (the largest through pore throat diameter)
- Mean flow pore diameter (50% of flow is through pores smaller than the mean flow pore)
- Pore diameter Range
- Pore distribution
Distribution function f:
- f = -d[(fw/fd) x 100] / dD
- fw = flow rate through wet sample
- fd = flow rate through dry sample
- Gas permeability in many desired units including Frazier, Gurley, Rayl and Darcy
Features
- Testing of small samples as well as complete parts
- Many sample geometry (Ex: sheets, rods, tubes, hollow fibers, cartridges, and powders)
- Use of many nonwetting liquids (Ex: water, alcohol, Silwick, and Galwick)
- Tests in QC, research, or any number of user defined modes
- See-through sample chamber available for visual observation
- Real-time graphic display
- Window based software for all control, measurement, data collection, data reduction, and report preparation
- Fully automated and computer controlled
Optional Capabilities
- Liquid Permeability: Measures liquid flow rate through the sample when pressure is applied on excess liquid on the sample. Volume of liquid measured using a penetrometer.
- Pressure Hold Test
- Hydro-head (break through pressure) test
- Integrity test
- Envelope Surface Area, Average Particle Size, and Average Fiber Diameter obtained from gas flow rate through dry sample
- Multiple sample chamber
- Sheffield smoothness test
- Burst pressure test
- Use of strong chemicals as working fluid like KOH solution and saline solution
- Elevated temperature test up to 200° C
- Upgrades for:
- Characterization of in-plane pores
- Characterizing very low permeability samples
- Sample under compression during test
Applications
Advanced Capillary Flow Porometers yield very objective, accurate and reproducible results, considerably reduce test duration, and require minimal operator involvement. Advanced Porometers are fully automated, and they are designed for linear turbulance-free test gas flow. The pressure is measured close to the sample and therefore the correction term in the differential pressure management is minimized. Required amount of pressure is uniformly applied on the o-ring seals on the sample and the need for hand tightening the cap on the sample chamber to apply pressure on the o-rings is eliminated. Automatic addition of wetting liquid reduces test time appreciably. This sophisticated instrument has found applications in a wide variety of industries.
For more information about the applications please see our other technical papers.
Specifications
For more information see our Advanced Capillary Flow Porometer brochure, Capillary Flow Porometer Brochure, Porometers Brochure, and Characterization of Pore Structure Brochure.