Patent attributes
A process for forming irrigation drip tape includes, broadly, the steps of a) supplying a longitudinally continuous strip of flexible plastic material in a first direction; b) heating a narrow band of the strip along a longitudinal axis thereof; c) depositing a continuous bead of material on an upper surface of the strip, along the narrow band, while the strip moves in the one direction; d) cooling the strip and the bead; e) folding the strip longitudinally so that the longitudinal edges overlap; and f) sealing said longitudinal edges to form a tubular drip tape with a longitudinal, overlapped seam, with the bead extending parallel to the seam and in opposed, facing relationship thereto. Apparatus for carrying out the process includes a first supply station adapted to supply a continuous length of flexible material; a second station including a trimmer roll and a pair of associated knife blades arranged to trim opposite longitudinal edges of the material to form a strip of predetermined width: a third station including a slitter wheel arranged to cut axially spaced longitudinal slits in the strip; a fourth station for applying a pre-formed bead of material onto a surface of the strip, the bead having one or more secondary flow paths formed therein; and a fifth station including a plurality of rollers arranged to wrap the strip about a mandrel into tubular form; a nozzle arranged to apply an adhesive bead along one of the longitudinal edges of the strip; and at least one pressure roller for applying pressure along the longitudinal edge to form a bonded seam between the longitudinal edges of the strip.
