| InstruQuest Inc. Scientific Instruments R&D |
Home > Permeametry
Gas (Air) Permeametry option in the HumiPyc gas (helium) pycnometers
2004 -2012 Copyright © InstruQuest, Inc. All rights reserved.
 | |  | |  | |  | |  | |  |
The basic premise of permeametry is that measurements of resistance to a gas flow through porous media
can yield the method-specific surface area.
Using a specially designed cell for holding a packed bed of powder and ancillary hardware, the HumiPyc Gas
(helium) pycnometers can be utilized as an automatic gas (air) permeameter. The main advantage of such
approach is that true density, porosity, and the specific surface area can be obtained using the same
instrument and automatically. Such quantities can be obtained for different gases, and in case of the HumiPyc
Model 1, at a range of temperatures.
In the simplest implementation, functionality similar to Blaine apparatus can be materialized. Pressurizing to a
programmable pressure value of the pycnometer fixed volume and opening the auxiliary valve, the pressure
values are recorded versus time.
can yield the method-specific surface area.
Using a specially designed cell for holding a packed bed of powder and ancillary hardware, the HumiPyc Gas
(helium) pycnometers can be utilized as an automatic gas (air) permeameter. The main advantage of such
approach is that true density, porosity, and the specific surface area can be obtained using the same
instrument and automatically. Such quantities can be obtained for different gases, and in case of the HumiPyc
Model 1, at a range of temperatures.
In the simplest implementation, functionality similar to Blaine apparatus can be materialized. Pressurizing to a
programmable pressure value of the pycnometer fixed volume and opening the auxiliary valve, the pressure
values are recorded versus time.
Using the provided software and selecting a pressure interval, the user can obtain time and calculate other
parameters using Carman-Kozeny equation. This air permeameter can be a viable option to determining fineness
of many powders, like hydraulic cement, for which the ASTM C204-07 method is used. As it is common practice in
air permeametry, standard reference material (NIST No. 114q in the case of hydraulic cement) of known surface
area can be used for relative determinations of specific surface area.
parameters using Carman-Kozeny equation. This air permeameter can be a viable option to determining fineness
of many powders, like hydraulic cement, for which the ASTM C204-07 method is used. As it is common practice in
air permeametry, standard reference material (NIST No. 114q in the case of hydraulic cement) of known surface
area can be used for relative determinations of specific surface area.
Experimental data of pressure versus time for cement sample
Advantages:
- Can measure specific surface area and true density of the packed bed in the same run
- No need to use mercury, manometric liquids, or glassware
- Yields complete data of pressure versus time for further studies
- Fully automated, software support for calculations
- Use of other gases then air
- Easy to implement different sizes and shapes of packed beds cells
- Possible use of vacuum for diffusion methods
- Possible implementation of constant flow permeameter
- Low cost compared to standalone automated air permeameters
- Can measure specific surface area and true density of the packed bed in the same run
- No need to use mercury, manometric liquids, or glassware
- Yields complete data of pressure versus time for further studies
- Fully automated, software support for calculations
- Use of other gases then air
- Easy to implement different sizes and shapes of packed beds cells
- Possible use of vacuum for diffusion methods
- Possible implementation of constant flow permeameter
- Low cost compared to standalone automated air permeameters
Humidification of dry packed beds to known RH (COMING SOON)
