Description

The Armfield Drain Permeameter is suited for use both as a teaching and demonstration tool and for laboratory testing and research. The equipment consists of a 100mm diameter transparent column, which may be filled with any soil type. A removable base section is provided into which the filter material to be investigated is placed. Water is added to the column under a constant head and permeating water and soil is collected at the base. The discharge from the drain can be monitored to assess the efficiency of the filter material. The apparatus is supported on a sturdy metal frame and may be conveniently placed on a laboratory bench close to a water supply and drain.

Experimental Content

• Determine relative efficiencies of drain filter materials
• Select optimum filter/soil combinations
• Demonstration of Darcy’s Law and to illustrate the various concepts in the Darcy equation: water potential, hydraulic conductivity and flow rate
• To investigate the influence of drain slot size variation of drain sediment yield and susceptibility to blocking
• Investigation of the dynamics of a gravel envelope