Desenvolvimento de um microaspersor fixo, de baixa pressão e distribuição setorial, para irrigação localizada.

Abstract

The objective of this work was t o develop a new mini - sprinkler from the initial model ED1, previously developed by UFPb in co-operation w i t h CANDE industries and DNOCS, aiming a t improving the following characteristics: sectorial distributionin wet strips , low working pressure (4 t o 6m) and low discharge rates, facility to manufacture and field operation besides, higher over all efficiency . The work consisted of three phases: conception, construccion o f prototype, and tests of the mini - sprinklers. During the conception phase existing mini - sprinklers were studied in order to define shapes and dimensions. This phase resulted in 10 alternatives of prototype. In the construction phase prototypes were built manually (handcrafted) i n P.V.C. and a crylic . The tests were carried out initially in a preliminary fashion and further in a definitiveway. The Christiansen coefficient of uniformity',/was the criteria employed to select the 3 best alternatives. Final tests were run to determine discharge rates, manu facturing variation coefficient, emission uniformity coefficient and Christiansen uniformity coefficient. The results allowed to conclude that: (i) Christiansen coefficient is recommended to evaluate distribution pattern for mini-sprinklers; ( i i ) alternative number 10 presented best coefficient for both spacing and pres sure range utilized , being selected as the b e s t alternative;, ( i i i ) pressure did not influence significant y Christiansen coefficient but spacing and mini-sprinkler characteristics did influence; and ( i v ) pressure and sprinkler characteristics influenced discharge rates significantly.