Air / Gas Pycnometer

Air / Gas Pycnometer

Item no.: 1480000 (with compressor) Item no.: 1480200 (with integrated compressor and connection for external gas)

Advantages at a glance

  • Large measuring chamber
  • Examination of large samples possible
  • No lancing cylinders required
  • No additional equipment required

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Air / Gas Pycnometer

Our air or gas pycnometer is an innovative measuring instrument for the determination of the air-filled pore volume, the solid volume as well as the solid density (dry bulk density) of a substrate sample in the laboratory. Especially the pore volume is a decisive factor for the evaluation of a soil for many questions of water balance, soil management or soil remediation. Air and water conductivity, as well as water and nutrient retention capacity are directly related to pore volume.

How does our air pycnometer work?

The measuring method is based on the fact that only the solid volume VF of a solid sample displaces gas, while pore or void volumes are filled with gas. The air or gas pycnometer consists of a measuring chamber and an additional chamber, which forms the additional volume Vz. The known additional volume is filled with compressed air or the connected gas and connected to the measuring chamber containing the substrate sample via a shut-off valve. Opening the valve results in pressure equalization within the two volumes.

Application areas

Our air or gas pycnometers are suitable for undisturbed soil samples as well as for bulk materials such as sands, gravels or plant granules.

  • UGT air pycnometer uses atmospheric air compressed inside the instrument and does not require an external gas supply line like a gas pycnometer. An air pycnometer is thus somewhat faster and less complex to operate than a gas pycnometer. For soil samples with a very high percentage of fines, the applicability of the air pycnometer may be limited, in part because nitrogen will attach to the soil particles and distort the measurement result (Amoozegar et al. 2022). Air pycnometers are therefore only suitable for samples with coarse to medium pores. The same applies when using a gas pycnometer with nitrogen.
  • The use of the UGT gas pycnometer with external gas connection enables the measurement with gases with defined properties under exclusion of influences by air components and air humidity (absorption and corrosion). This is particularly recommended for soil samples with a high fine content (such as clay).

The large measuring chamber with a volume of approx. 2100 cm³ enables the examination of correspondingly large samples.

For air as well as gas pycnometer are included:

  • Mains cable
  • Closing bracket with clamping screw
  • Cover sample chamber
  • Sealing ring

Required accessories for gas pycnometer: Supply hose for external gas

Optional accessories: Additional volume 100 cm³ for air pycnometer (Art.-No.: 1480100)

Measuring chamber



12 cm


15 cm


≈ 2120 cm³

Max. pressure

4 bar

Max. temperature

100 °C

Min. temperature

5 °C

Pressure vessel additional volume



≈ 1000 cm³





Power supply

230 V

Protection CEI529


Height with lid and bracket

52 cm

Height without lid and bracket

38 cm


46 cm


39 cm

Weight with lid and bracket

15,3 kg

Weight lid

1,7 kg

Weight bracket

2 kg

Digital manometer


Measuring range

-1 to 3 bar absolut pressure


1 mbar


10 bar

Accuracy (at room temperature)

< 0,1 %FS

Overall error range

< 0,2 %FS

Storage / working temperature

-20…70 °C / 0…50 °C

Compensated temperature range

0…50 °C

Power supply

3 V battery, CR 2430

Battery life

  • 11000 hours continuous in Mano mode
  • 150 hours continuous in peak mode

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