Sandbox for pF determination

The box is suitable for sample rings with a diameter of 53 or 60 mm and a height of 5 cm. A correctly installed sandbox can last for years without use of additional consumables.

The standard sandbox set includes:

• A steel container with a three-way valve for filling, closing or draining (applying suction pressure)
  

• A regulator for the different suction values between pF 0 and pF 2.0

• Synthetic sand

• Water bottle to fill the box from below

Additional requirements:

A correct determination in the sandbox uses undisturbed samples in sample rings. To obtain these samples, a soil sample ring kit is required. The laboratory should be equipped with a drying oven and an accurate balance. The table on which the instrument is placed should be at least 90 cm high, level and free from vibration. 

Determination process:

The box is filled with synthetic sand that is then completely saturated. There should be no air bubbles in the sand or in the piping of the system. The pre-saturated and weighed sample rings with soil are placed in the box. Subsequently, a certain level of suction is exerted on the samples by means of the regulator, causing the samples to lose moisture. At equilibrium, i.e. when the samples no longer lose moisture as the suction pressure is applied, the final weight is recorded. Subsequently, the determination is repeated with an increasing suction.

Applications:

• Soil physical laboratory research