摘要 |
A drip irrigation tube (10) formed by longitudinally folding an elongated web having a thick marginal side wall (26), an intermediate central wall (20), and a thin marginal side wall (24), and overlapping and sealing the marginal side walls (24, 26) to form a tube (10). Discrete emitter elements are disposed at spaced intervals along the web and are formed by embossing or otherwise forming recessed emission grooves in the outer overlapping marginal side wall (26) so as to form a flow path from the inside of the tube (34) to the outside. The emitter elements operate to provide a constant flow rate over a wide range of working pressures by controlled deformation and constriction of size of relatively short regulatory passageways (44) formed by a portion of the emission grooves. |