(57) The present invention provides a new and advantageous screen structure which is capable
of more applications than known screen structures.
The screen structure proposed comprises curved rod or wires or other elongage (filamentary)
material (R; S') for which screening spacings (x) are at progressively increasing
radial distance from an axis up to a boundary rod or wire, also curved about said
axis. Not only can the proposed structure be used flat, but it can also be formed
into three dimensional screens including conical and helical structures.
One method of making such a screen for example comprises using a grooved table (70)
and feeding a plurality of wires into the grooves and means serving to import requisite
relative movement between such table and such rod or wire. Means (18) is provided
for securing radial supports (12) to the screen elements made on the table, conveniently
by welding.
Another apparatus for making the screens comprises a plurality of spaced grooved radial
members (101) and corresponding spaced radial location members (107) for locating
wires in the grooves.
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