| 摘要 |
The lining for trickle irrigation is composed of at least two shaped segments, that is to say a flat segment A and a 3-D segment B joined in an assembly unit. The flat segment A of the lining is composed of longitudinally grooved flat elements, in which the longitudinal grooves are terminated by a transverse groove. Every element has a flat surface on the edges. The three-D element B is composed of left b and right b' elements which are alternately inserted, one having the appearance of a regular reflection of the other. Each three-D element is formed by a hypersurface situated above the orthogonal projection of the element, advantageously formed by the surface defined in a straight manner 4 and 4' in the form of a hyperbolic paraboloid, bounded on the two shortest opposite sides by oblique surfaces, advantageously by planes, and having in the opposite corners planes of contact with the neighbouring segments. The surface defined in a straight manner is advantageously grooved crosswise by two families of hyperbolic paraboloids. <IMAGE>
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