Abstract: A pressure plate extractor for testing of soils and other porous solids has a pressure chamber defined by pressure chamber sidewalls resting above a pressure chamber base. A drain plate is situated on the pressure chamber base with its bounding edge surrounded by a seal and situated inwardly from the pressure chamber sidewalls, which rest atop the seal. When the pressure chamber sidewalls are urged towards the pressure chamber base, thereby compressing the seal and preventing air from passing between the pressure chamber sidewalls and pressure chamber base, the seal laterally expands to firmly engage the bounding edge of the drain plate, thereby preventing air from passing between the pressure chamber sidewalls and the drain plate. A substantially leak-free pressure chamber results, with low probability of drain plate failure because the pressure chamber sidewalls do not bear directly upon it.

Abstract: A pressure plate extractor for testing of soils and other porous solids has a pressure chamber defined by pressure chamber sidewalls resting above a pressure chamber base. A drain plate is situated on the pressure chamber base with its bounding edge surrounded by a seal and situated inwardly from the pressure chamber sidewalls, which rest atop the seal. When the pressure chamber sidewalls are urged towards the pressure chamber base, thereby compressing the seal and preventing air from passing between the pressure chamber sidewalls and pressure chamber base, the seal laterally expands to firmly engage the bounding edge of the drain plate, thereby preventing air from passing between the pressure chamber sidewalls and the drain plate. A substantially leak-free pressure chamber results, with low probability of drain plate failure because the pressure chamber sidewalls do not bear directly upon it.