Feed spacer for reducing differential pressure of reverse osmosis element, and formation nozzle
Provided is a feed spacer for reducing differential pressure of a reverse osmosis element, the feed spacer forming the reverse osmosis element, the feed spacer comprising a plurality of strands disposed in a mesh shape having predetermined intersection points, and wherein a vertical cross section of each of the strands has a rhombic shape such that a pressure loss in the feed spacer is minimized by an effective flow of raw water at an interface of a reverse osmosis membrane, and a nozzle for forming the feed spacer.
1. A feed spacer for reducing differential pressure in a reverse osmosis element, comprising a plurality of strands disposed in a mesh shape having predetermined intersection points, the plurality of strands forming a mesh having a two-layer structure, wherein a first set of the plurality of strands form a first layer, and a second set of the plurality of strands are disposed on the first layer forming a second layer,
wherein a vertical cross section of each of the strands of the first layer and the second layer has a rhombic shape having four sides that meet to form four vertexes, and a thickness of the first set of strands and a thickness of the second set of strands has a constant value of h/2, measured from a first vertex to an opposite non-adjacent second vertex of the rhombic shape,
wherein a thickness of the feed spacer has a constant value of h when the second layer is disposed on the first layer,
a length between the intersection points between the strands is 3.8 to 4.63 mm, the thickness of the feed spacer is 0.5 to 2.0 mm, and the differential pressure in the reverse osmosis element decreases as a ratio of the length between the intersection points of the strands to the thickness of the feed spacer increases, and the ratio of the length between the intersection points of the strands to the thickness of the feed spacer is 4.49 or more, and
an angle at one side of the intersection points of the first set of the plurality of strands and the second set of the plurality of strands is 75° to 80°.
2. The feed spacer of claim 1 , wherein the lengths between the intersection points of the plurality of strands all are equal to one another.
3. A nozzle for forming a feed spacer for reducing differential pressure in a reverse osmosis element, the nozzle comprising:
a dual structure comprising an outer nozzle and an inner nozzle that are in contact with each other;
the outer nozzle comprises a first plurality of slots positioned along an inner circumference, and the inner nozzle comprises a second plurality of slots positioned along an outer circumference, so that the first plurality of slots and the second plurality of slots are positioned at a portion where the outer nozzle and the inner nozzle are in contact with each other;
wherein each slot of the first plurality of slots and each slot of the second plurality of slots have a rhombic shape,
wherein each slot of the first plurality of slots and each slot of the second plurality of slots are positioned so that a vertex of the rhombic shape points toward the portion where the outer nozzle and the inner nozzle are in contact with each other, and
wherein the nozzle forms a feed spacer comprising a plurality of strands disposed in a mesh shape having predetermined intersection points, the plurality of strands forming a mesh having a two-layer structure, wherein a first set of the plurality of strands form a first layer, and a second set of the plurality of strands are disposed on the first layer forming a second layer, wherein a thickness of the feed spacer has a constant value of h,
wherein a vertical cross section of each of the strands has a rhombic shape having four sides that meet to form four vertexes, and a thickness of the first set of strands and a thickness of the second set of strands has a constant value of h/2, measured from a first vertex to an opposite non-adjacent second vertex of the rhombic shape,
a length between the intersection points between the strands is 3 to 5 mm, the differential pressure in the reverse osmosis element decreases as a ratio of the length between the intersection points of the strands to the thickness of the feed spacer increases, and the ratio of the length between the intersection points of the strands to the thickness of the feed spacer is 4.49 or more.
4. The nozzle of claim 3 , wherein a length of the first plurality of slots and the second plurality of slots is adjustable.
5. The nozzle of claim 3 , wherein each slot of the first plurality of slots and each slot of the second plurality of slots has a size that is adjustable.