Membrane Apparatus for PF Determination (PF 3.0-4.2)

Method

The determination of the range pF 3.0 – 4.2 (1.0 – 15.5 bar) with the membrane apparatus does not use samples cut in sample rings, but the semi-disturbed sample is saturated before measurement in the laboratory and placed in a synthetic ring.

To reach the high values of the pF-curve, it is necessary to apply pressure, up to 15.5 bar, on the samples, as it is not possible to create that amount of suction force. On reaching the equilibrium at the desired pressure value, the samples are removed, weighed, dried and weighed again.

For measuring larger series of samples, an additional membrane extractor can be connected parallel to the first extractor.

The membrane apparatus contains:

• Pressure membrane extractor suitable for a maximum of 15 samples
• 20 bar compressor including reducing valve
• Pressure gauge
• Air filter
• Hoses
• Cellophane membrane
• Filter cloth
• Synthetic soil sample retaining rings
• Various accessories