Abstract Wound well screens and industrial filter screens are made with circular rather than polygonal cross-sections by preforming the wrapping wire with powered bending rollers, feeding it while curved and without tension into tangential contact with a plurality of spaced, circularly arranged, longitudinally extending screen rods, and welding the wire to the rods at each point of contact. Synchronization of the speed of rotation of a welding mandrel carrying the plurality of rods and of the feed of the wrapping wire is accomplished by causing the wire to assume the shape of a plurality of helical, loosely coiled turns about the periphery of the rods between the point of bending and the point of welding and varying the feed of the wire as necessary.
In a cylindrical welded screen making apparatus of the type having a rotating weld head, a welding roller, and a carriage for rotating and longitudinally advancing a plurality of rods as a wire is helically wrapped around them and welded to them, the improvement comprising a set of preforming rollers for feeding said wire, said preforming rollers being positioned close to said rods but axially spaced from said welding roller so that said wire is loosely coiled through at least one revolution about said rods between said preforming rollers and said welding rollers, at least one of said preforming rollers being powered, and means for adjusting the rate of feed of said wire by said preforming rollers so that the size of the coil of wire can be maintained at approximately a predetermined size.
Claim 2
Dependent Claim
134 words
In a cylindrical welded screen making apparatus of the type having a rotating weld head, a welding roller, and a carriage for rotating and longitudinally advancing a plurality of rods as a wire is helically wrapped around them and welded to them, the improvement comprising a set of preforming rollers for feeding said wire, said preforming rollers being positioned close to said rods but axially spaced from said welding roller so that said wire is loosely coiled through at least one revolution about said rods between said preforming rollers and said welding rollers, at least one of said preforming rollers being powered, and means for adjusting the rate of feed of said wire by said preforming rollers so that the size of the coil of wire can be maintained at approximately a predetermined size.
Claim 3
Dependent Claim
26 words
The apparatus of claim 1 and further including a guide roller positioned immediately adjacent said welding roller for guiding said wire just before it is welded.