Filter screen
Provided is a filter screen having a plurality of slots, each slot having a longest principal axis A1 that has a length L, and each slot having a second axis A2 that is perpendicular to A1 and that has a length W, wherein the distance between adjacent slots in the direction of the axes A2 is XP; wherein XP is greater than W; wherein the distance between adjacent slots in the direction of the axes A1 is YP; either wherein L is 800 micrometers or less and XP is 350 micrometers or less, or wherein L is 1600 μm or less and XP is 180 μm or less. Also provided is a method of filtering feed water using such a filter screen.
1. A filter screen having a plurality of slots, each slot having a longest principal axis A1 that has a length L, and each slot having a second axis A2 that is perpendicular to A1 and that has a length W, wherein the slots are arranged so that
all the axes A1 are parallel to each other;
the slots are disposed in a plurality of rows, wherein the distance between center points of adjacent slots in the direction of the axes A2 is XP; wherein XP is greater than W;
the slots are disposed in a plurality of columns, wherein the distance between nearest circumference points of adjacent slots in the direction of the axes A1 is YP;
wherein L is 800 micrometers or less,
wherein XP is 350 micrometers or less,
wherein W is 50 micrometers or less, and
wherein the filter has a curved surface.
2. The filter screen of claim 1 , wherein the curved surface is enclosed by top and bottom surfaces.
3. The filter screen of claim 1 , wherein XP is 200 μm or smaller.
4. The filter screen of claim 1 , wherein within each row the axes A2 are collinear.
5. The filter screen of claim 4 , wherein within each column the axes A1 are collinear.
6. The filter screen of claim 1 , further comprising:
one or more brushes engaged with the filter screen.
7. The filter screen of claim 1 , wherein the slot has a shape along the Z axis that is substantially uniform.
8. The filter screen of claim 1 , wherein 90% or more of the slots have W that has a quotient of W/Wav of from 0.8 to 1.2, and wherein Wav is the average width of the slots in that screen.