Method and apparatus for forming ports in drip irrigation hose

A method for making drip irrigation hose from a continuous length of plastic film having first and second longitudinal margins, the hose having a large water supply passage, a small flow regulating passage, sets of inlet ports from the supply passage to the regulating passage, and sets of outlet ports from the regulating passage to the exterior of the hose, the method comprising the steps of:

• deforming without puncturing the surface of one margin of the film at periodic intervals along its length corresponding to the location of one of the sets of ports to form spaced apart clusters of protrusions from the surface of the one margin;
• slicing the ends of the protrusions from the film to form the one set of ports;
• forming the other set of ports;
• folding the film along its length to overlap the margins so the second margin is external and the first margin is internal;
• and
• sealing the overlapping margins on both sides of the inlets and outlets along the length of the film to form the regulating passage between the overlapping margins from which water can flow through the outlets to the exterior of the hose and the supply passage within the remainder of the film from which water can flow through the inlet ports to the regulating passage.