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Mercury Porosimetry

Pascal 140-240/440 EVO

 

PASCAL EVO Porosimeter conform to the "Pressure Equipment Directive PED"  EC  97/23


Fully automated Mercury Porosimeters for the determination of pore size distribution, mean pore radius, total pore volume, specific pore surface, mercury density and particle size of finely divided and porous materials. Different instruments and options allow the possibility to determine pore radii from 900 micron to 1.8 nm and particle diameters from 3 mm to 15 nm.

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The mercury porosimetry technique is one of the most useful methods to investigate the porous structure of solid samples in a quantitative way. It provides reliable information about pore size/volume distribution, bulk and apparent density and specific surface for most porous materials, regardless of their nature and shape. Mercury porosimetry analysis is based on the intrusion of mercury into the solid material porous structure under controlled pressurisation. The pressure needed for intrusion according to the Washburn-equation is:

 

r - pore radius

ϒ - surface tension of mercury

θ - contact angle

ρ - pressure

P.A.S.C.A.L. fits your sample

The pressurisation procedure is critical to the accuracy and speed of the analysis because a certain equilibrium time is required for the mercury to fill pores at each pressure. This depends on the external pore access diameter and on the shape and complexity of the pore geometry. In principle, it is impossible to know which pressure rate is the most suitable for an unknown sample because an excessively high pressurisation rate gives wrong results since the pores are not completely filled at the corresponding real intrusion pressure. On the contrary a low pressurisation speed wastes valuable laboratory time

The solution is the 


"Pressurization by Automatic Speed-up and Continuous Adjustment Logic"


or, in short, PASCAL, a new operating principle developed by the microstructure department of ThermoElectron and used in the new generation of automatic mercury porosimeters of the PASCAL EVO series. The PASCAL method automatically determines the correct pressurisation speed according to the presence of pores and to the real penetration rate of mercury into the pores, thereby eliminating wasted time during the analysis. The PASCAL method combines all the benefits in one system.

 

 

Pascal filling station

In many cases mercury porosimetry is used to characterize larger pieces of porous materials with pores below the micrometer range. Here the filling device can be an interesting alternative to the Pascal 140 EVO. The filling device can be used for all kind of dilatometers.With the filling device the pressure during the filling procedure can easily be controlled, so samples with residual moisture can be filled at pressures above the vapour pressure of water (2kPa) and the measurement can be performed for the real life sample.

PoreXpert (optional)

Research Suite

 

PoreXpert generates a trial 3-dimensional void network and gradually refines it until it finds a network which closely matches the experimental sample. If a sample was constructed containing the simulated void network and then dropped into a mercury porosimeter or soaked in water and then sucked dry on a tension table, its characteristics would be almost identical to those of the experimental sample. PoreXpert has some major approximations, the main one being that the shapes of the pores are still simplified – in this case to cubic ‘pores’ connected by smaller inter-connecting cylindrical ‘throats’. However, the shapes of the pores have little effect on most of the important properties of porous solids and their pore fluids. What really matters are the sizes of the cross-sections of the pores and throats and the way they are linked together three-dimensionally. These properties are quantitatively linked to the experimental sample.

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Calendar

ExhibitionExhibition
ConferenceConference
WorkshopWorkshop
13. - 14. November 2018
XIX. Porotec Workshop
Niedernhausen