Controls Group Falling head permeability apparatus Falling head permeability apparatus

Falling head permeability apparatus

General description
General description
The soil permeability is a very important factor to study the behavior of soil in its natural condition with respect to water flow. The falling head method is particularly suitable for fine-grained soils such as clay-like or silty soils in the range of 1x10-2 to 1x10-6 cm/s. For relatively coarse grained soils such as sands and gravel see Constant Head permeability apparatus.
The test is performed with a permeability cell (38-T0185/1), which has to be connected to a manometer stand (38-T0185/2). During the test the cell is placed in a soaking tank (38-T0185/3) fit with overflow tube and the saturation is verified with the Vacuum control panel (38-T0185/4). As an option the apparatus can be completed with a suitable de-airing tank (28-WF4220/A) and De-airing system. See accessories.
The permeability cell is made of plated steel. The base and the top are clamped with stainless steel rods. Complete with 75 micron gauze. Supplied complete with 2 m tubing.
More +

Technical specifications

Permeability cell 38-T0185/1
  • Inside diameter: 100 mm
  • Weight approx.: 4 kg

Stand 38-T0185/2
  • 4 manometer glass tubes 1500 mm: 21, 12, 5 and 3.5 mm inside diameter
  • Wooden panel dimensions: 1680x280 mm
  • Weight approx.: 3.6 KG

Soaking reservoir 38-T0185/3
  • Made from plated steel
  • Complete with overflow tube
  • Dimensions: dia. 230 mm x 230 mm high
  • Weight approx.: 2.3 kg

Vacuum control panel 38-T0185/4
Used for the saturating the samples. Complete with:
  • Adjustable vacuum valve
  • Vacuum gauge
  • Two manifolds of 3 and 6 lines
  • Weight approx.: 3 kg

Ordering info

Falling head permeability cell

Stand with 4 manometer tubes

Soaking reservoir

Vacuum control panel


De-airing tank


De-airing tank, 7 liters capacity
De-airing tank, 23 liters capacity

Vacuum Pump


Portable vacuum pump, free air displacement 75 l/min, ultimate vacuum 0.1 mbar. 230V/50-60Hz/1Ph.

Air drying unit for use with silica gel with the indicator 86-D0819

Silica gel 1 kg

Rubber tube dia 6.5 x 16.5 mm, 2 m long, for vacuum pump.