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.
