Abstract: Membrane elements that use multiple membrane leaves may have a limited total active membrane area due to an increased diameter at the ends of the element. Membrane leaves may comprise a permeate carrier positioned between one or more membrane sheets. Adhesive may be used to seal one or more edges of the membrane leaf. The membrane sheets, permeate carrier and the adhesive contribute to the thickness of the edges of the membrane leaf and the diameter at the ends of the element. A reduced thickness of the edges of the permeate carrier may reduce the diameter at the ends of an element. Another permeate carrier sheet may also be used that is distanced from at least one edge of the membrane sheet so the permeate carrier sheet does not contribute towards the increased diameter at the ends of the element.

Abstract: A permeate carrier to be described in detail below has side edges, alternatively called borders, that are thinner than a central part of the permeate carrier. Adhesive is applied to the side edges to form a seal when a membrane leaf is formed around the permeate carrier. After the membrane leaf is wound around a central tube, the side edges extend in a spiral around the central tube. The transition between the side edges and the central part of the permeate carrier helps prevent adhesive from flowing into the central part of the permeate carrier. The reduced thickness of the side edges also reduces an increase in diameter at the ends of an element that might otherwise be caused by the adhesive.

Abstract: Membrane elements that use multiple membrane leaves may have a limited total active membrane area due to an increased diameter at the ends of the element. Membrane leaves may comprise a permeate carrier positioned between one or more membrane sheets. Adhesive may be used to seal one or more edges of the membrane leaf. The membrane sheets, permeate carrier and the adhesive contribute to the thickness of the edges of the membrane leaf and the diameter at the ends of the element. A reduced thickness of the edges of the permeate carrier may reduce the diameter at the ends of an element. Another permeate carrier sheet may also be used that is distanced from at least one edge of the membrane sheet so the permeate carrier sheet does not contribute towards the increased diameter at the ends of the element.

Abstract: Membrane elements that use multiple membrane leaves may have a limited total active membrane area due to an increased diameter at the ends of the element. Membrane leaves may comprise a permeate carrier positioned between one or more membrane sheets. Adhesive may be used to seal one or more edges of the membrane leaf. The membrane sheets, permeate carrier and the adhesive contribute to the thickness of the edges of the membrane leaf and the diameter at the ends of the element. A reduced thickness of the edges of the permeate carrier may reduce the diameter at the ends of an element. Another permeate carrier sheet may also be used that is distanced from at least one edge of the membrane sheet so the permeate carrier sheet does not contribute towards the increased diameter at the ends of the element.

Abstract: A feed channel spacer for a spiral wound membrane element has inlet and outlet edges that are thinner than the rest of the spacer material. The edges may be made thinner, for example, by passing the edges of a sheet of feed spacer material through a pair of hot rollers or by compressing the edges of the sheet in a heated press. The thinned edges of the feed spacer material are located in the element between glue lines applied to the permeate spacers of the element. The thin edges allow a greater membrane surface area to be provided in a given element diameter. A feed channel spacer may also have an area with obstructions to create micro-mixing effects. These obstructions may be provided on a feed spacer sheet of constant thickness, or one with thin edges.

Abstract: A feed channel spacer for use in a spiral wound membrane element provides a series of generally parallel interior channels. The interior channels extend from an inlet side of the spacer to an outlet side of the spacer, but follow an undulating or zigzagging path. Dean's vortices or other flow patterns that cause mixing reduce concentration polarization. The feed channel spacer is made by pressing a sheet of thermoplastic material in a die.

Abstract: A spiral would membrane element has a feed channel spacer providing a tortuous feed flow path through an open spacer mesh material. The feed flow path may force the feed liquid to flow across substantially all of an adjacent membrane surface. The length of the flow path and average cross-flow velocity are increased relative to a straight flow path. A rise in pressure drop that might otherwise be produced by the increased average cross-flow velocity is reduced by the open spacer mesh. In a system having two or more upstream and downstream spiral wound membrane elements, a downstream element may have a feed channel spacer providing a tortuous flow path while an upstream element has a feed channel spacer providing a less tortuous flow path or a straight flow path.

Abstract: A permeate carrier for a spiral wound membrane element has two or three layers, for example of tricot construction. The two outer, or only, layers resist movement of the membrane sheet into permeate channels in the permeate carrier. The total thickness of the permeate carrier sheet may be similar to the thickness of typical tricot permeate carrier sheets. The permeate carrier sheet may be coated to make its surfaces hydrophilic. The coating may be, for example, a cross-linked polyvinyl alcohol (PVA) or polyvinyl pyrrolidone (PVP). In the spiral wound element, a permeate carrier sheet may be wrapped in one or more layers around a central tube. Channels in the permeate carrier sheet are oriented helically relative to a longitudinal axis of the central tube.

Abstract: A permeate carrier to be described in detail below has side edges, alternatively called borders, that are thinner than a central part of the permeate carrier. Adhesive is applied to the side edges to form a seal when a membrane leaf is formed around the permeate carrier. After the membrane leaf is wound around a central tube, the side edges extend in a spiral around the central tube. The transition between the side edges and the central part of the permeate carrier helps prevent adhesive from flowing into the central part of the permeate carrier. The reduced thickness of the side edges also reduces an increase in diameter at the ends of an element that might otherwise be caused by the adhesive.

Abstract: Membrane elements that use multiple membrane leaves may have a limited total active membrane area due to an increased diameter at the ends of the element. Membrane leaves may comprise a permeate carrier positioned between one or more membrane sheets. Adhesive may be used to seal one or more edges of the membrane leaf. The membrane sheets, permeate carrier and the adhesive contribute to the thickness of the edges of the membrane leaf and the diameter at the ends of the element. A reduced thickness of the edges of the permeate carrier may reduce the diameter at the ends of an element. Another permeate carrier sheet may also be used that is distanced from at least one edge of the membrane sheet so the permeate carrier sheet does not contribute towards the increased diameter at the ends of the element.

Abstract: An interconnector coupling permeate conduits in a filtration apparatus includes a diverging section. The diverging section defines a generally increasing cross sectional area for the permeate solution exiting the interconnector in a direction of flow from the permeate conduit of a first separation element to a permeate conduit of a second separation element. The diverging section provides a more gradual divergence of the permeate solution to reduce pressure losses.

Abstract: A filtration apparatus includes plurality of membrane modules arranged in series in a chamber. The membrane modules include at least one lead membrane module closer to an inlet port than the remaining membrane modules. A device coupled to the permeate collection conduit of the at least one lead membrane module is configured to apply a back pressure to permeate solution flowing in the permeate collection conduit of the at least one lead membrane module. By applying a back pressure, flux imbalance may be reduced within the apparatus.

Abstract: A particulate laundry detergent composition which comprises a detergent base powder comprising surfactant and builder and, as separate particulate components: (a) an alkali metal carbonate salt selected from carbonate, bicarbonate, sesquicarbonate and combinations thereof; and (b) a water-soluble organic acid which, when reacted with (a) in the presence of water, generates carbon dioxide gas; wherein the alkali metal carbonate salt, when taken separately, has a 90% dissolution time of less than 15 seconds, preferably less than 10 seconds, more preferably less than 7 seconds; and the water-soluble organic acid has a d50 particle size which is in the range of from 150 to 1500 microns. The alkali metal carbonate salt preferably has an average bulk density of at most 1000 g/l, preferably at most 800 g/l, more preferably at most 600 g/l. The alkali metal carbonate salt preferably has a d50 particle size of at most 250 microns, preferably from 1 to 200 microns, more preferably from 10 to 150 microns.

Abstract: A particulate laundry detergent composition which comprises a detergent base powder comprising surfactant and builder and, as separate particulate components:

Abstract: A particulate laundry detergent composition which comprises, as separate particulate components:

Abstract: A particulate laundry detergent composition which comprises, as separate particulate components: