The mercury porosimeter is capable of measuring pore size and size distribution, pore volume, pore surface area, diameter, bulk and apparent particle densities and % porosity. The measurement is made by measuring the mercury inlet volumes into the material at different pressures. The device works based on the physical principle that an unreactive, non-wetting liquid cannot enter small pores in the material unless sufficient pressure is applied. The relationship between pore diameter and applied pressure is obtained by the Washburn equation (D=(-4γ cosθ)/P).

The fully automatic mercury porosimeter has three sample chambers, two low pressure and one high pressure, with a pressure range from 0 to 60,000 psi. The measurable pore size ranges from 0.003 µm to 900 µm. The system is computer controlled. Intrusion and extrusion data can be obtained in the measurements.