Patent ID: 6065901
Filing Date: 2000-05-23
Classification: E02D,Y10S

Abstract:
A system for use in preventing a flow of gas from a gas-containing region to an adjacent region, comprising a composite barrier installed so as to separate the two regions, the composite barrier comprising a gas-impermeable layer including at least one aperture and a gas-permeable membrane defining an interspace between the gas-impermeable layer and the gas-permeable membrane and arranged with the permeable membrane facing the gas-containing region, means for restricting the movement of the gas at the perimeter of the composite barrier, said restricting means comprising the interspace between the impermeable layer and the permeable membrane being closed entirely around the perimeter of the barrier apart from the at least one aperture, and pumping means connected to the at least one aperture of the composite barrier communicating with the interspace for pumping the gas into the interspace so as to create a pressure differential across the permeable membrane whereby to cause the gas to flow therethrough across at least a major portion of the surface of the permeable membrane.