Abstract: The invention concerns an apparatus and method for determining pore volume parameters of a solid sample. The apparatus comprises a high pressure cell (50), a sample holder (1) provided with an orifice (21), means (2) for creating a vacuum connected to a chamber (10a) containing the sample holder by at least one orifice (30), and a mercury supply. The apparatus also comprises a syringe pump (9) connected to the chamber and to mercury supply means for delivery of mercury under pressure, means for programming a steady supply of mercury for a fixed period of time connected to the pump, at least one pressure sensor (15) downstream of the pump which continuously reads the pressure, and means (41) for signal collection and processing connected to the pressure sensor and the means for programming a steady supply of mercury and adapted to calculate the porosimetry parameters.

Abstract: For measuring the adsorption and desorption of a gas adsorbed by a solid sample, a gas pressure drop during the adsorption phase or a gas pressure increase during the desorption phase is programmed in the reservoir circuit 1 from 0.1 to 0.7 Pa per minute by at least one regulating valve V.sub.P1 having a proportional opening, in order to transfer a substantially constant flow of gas to the sample and from the sample to the reservoir, the gas pressure being measured periodically in the measuring circuit by pressure sensors. By a microprocessor, the isotherm of adsorption and desorption is determined based on the volume of the reservoir circuit, the quantity of gas transferred, the gas pressure in the measuring circuit, and the volume of the measuring circuit. The system measures the adsorption-desorption isotherms of a gas from a solid.