Abstract: An evaporation device has an inner tube and an outer tube. The inner tube is made of a hydrophilic membrane, such as DutyionT. The outer tube is preferably made of a material that readily absorbs solar radiation and is a good heat conductor. There is a gap between the inner tube and the outer tube for the flow of air. The inner tube contains a flow of impure water. The hydrophilic membrane allows water to pass to the outside of the inner tube as vapor, but prevents impurities from passing through. Air flowing in the gap takes up the water vapor and humidified air exits the evaporation device. This humidified air is subsequently cooled to collect the vapor and provide purified water, e.g. at a condenser.

Abstract: Water vapor is introduced into an inlet air stream (16) of an engine (12), for example, by a pervaporation process through a non-porous hydrophilic membrane (18). A water reservoir (20), which can contain contaminated water, provides a vapor pressure gradient across the hydrophilic membrane (18) into the inlet air stream (16), while the rate of delivery of the water vapor to a cylinder (38-40) is self-regulated by the rate of flow of air across the membrane. The hydrophilic membrane (18) therefore also filters the water from the water reservoir (20) to an extent that pure water vapor is provided to the air inlet stream (16). Delivery of water vapor can nevertheless be controlled using a hood (26) that slides over the hydrophilic membrane to limit its exposed surface area.

Abstract: A mechanical water still (10) includes an impervious dome-like upper surface (12) and a membrane base (14) that is coupled (26) to the impervious dome-like structure (12) to form, when inflated, a chamber (20). The membrane base (14) supports a water pervaporation process therethrough. A water collection well (16) has an opening into which water droplets condensed from the water pervaporation process collect. The water collection well (16) is sited within the membrane base (14) and generally extends outwardly and downwardly from the membrane base (14), as shown in FIG. 1. In use, a contaminated water source (24) is brought into, ideally, complete contact with the membrane base (14), with the water collection well (16) arranged both to act as a heat sink into the water source (24) and to provide stability to the water still (10) when floating and immersed in the water source (24).