Wire wrap screens comprise a perforated base pipe having a plurality of spaced axially oriented rods over which a wire generally having a trapezoidal cross section is wrapped continuously and spot welded to the rods as the winding process continues. Fairly sophisticated machines such as illustrated in FIG. 2 of US 2005/0125980 are used to wrap the single wire around the axially oriented rods to make a screen that is of a particular diameter. As is also illustrated in FIG. 5 of this reference, nested wire wrap screens of different dimensions can be produced at the same time with a single wire feed going on at the same time for constructing the screens that have different outside diameters. Even when building nested screens at the same time, each screen is assembled with a single wire feed. This is a rather slow process that could require as much as 90 minutes for the fabrication of 20 feet of screen. The fabrication process involves feeding wire on a rotating hub of a base pipe with spaced axially oriented rods and spot welding the wire to the rods periodically to maintain the wire spacing on the wraps. It is the wire spacing that determines the particle size that will be retained on the wires when the finished screen is in use.
Other techniques called pre-pack put a filtering layer under the wire wrap as illustrated in U.S. Pat. No. 5,190,102. Other manufacturing techniques for wire wrap screens involve the use of expansion to assemble the wrapped wire and base pipe together as illustrated in U.S. Pat. No. 8,096,037.
What is needed and provided by the present invention is a production method for wire wrap screens that increases the manufacturing speed of such screens. This is accomplished with a feeding technique that feeds multiple wires that begin at circumferentially spaced locations so that for every revolution of the rotating hub assembly multiple windings of wire are applied and spot welded or otherwise attached. At the opposite end of the screen the individual wires are terminated at circumferentially offset locations similar to the initial end of the manufactured screen so that the ends may be transverse to the longitudinal axis to permit end sealing with caps to be welded or simply by welding the ends to the base pipe and rods that underlie the wire wrapping. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.