Drip Irrigation Pipe Research Articles

Experimental Processing of Biodegradable Drip Irrigation Systems—Possibilities and Limitations

The increased cost associated with the waste removal and disposal of conventional agricultural plastic in contact with the soil combined with the gradually decreasing cost of the biodegradable plastics allowed the commercialization of biodegradable mulching films. Since the conventional thin wall or tape drip irrigation system lies under the mulching film and is used for one season only, it would be desirable to replace it with a biodegradable one. This paper presents the results of a research work investigating the possibilities and limitations in developing biodegradable drip irrigation thin wall pipes and pipes. The first ever experimental biodegradable drip irrigation thin wall pipes were produced. Rigid pipes were also produced for experimental purposes. Manufacturing problems were encountered in the processing of the biodegradable drippers and irrigation thin wall pipes with the experimental materials due to the complex formulation of the raw materials and the fact that the machinery used was specifically designed for PE processing. Experimental biodegradable thin wall pipes made of Bioflex with embedded drippers made of Mater-Bi were produced. The processing problems encountered with the production of thin wall pipes were surpassed during the experimental production of rigid type irrigation pipes. A biodegradable rigid irrigation pipe made of a grade of Mater-Bi, with embedded cylindrical drippers made of another grade of Mater-Bi was produced successfully. A better understanding of the thermal profile of the biodegradable raw materials and the use of processing equipment adapted to this profile might allow in the future the manufacturing of thin wall drip irrigation pipes for agricultural applications, and the use of alternative biodegradable materials.

Development of Prediction Models for Friction Losses in Drip Irrigation Laterals equipped with Integrated In-line and On-line Emitters using Dimensional Analysis

This paper presents models developed to predict friction head losses in drip irrigation laterals. Some domestic and imported drip irrigation laterals equipped with integrated in-line and on-line emitters placed at different spacings ranging from 0·2 and 1 m were considered in this study. The parameters affecting the variation in friction head losses in laterals were defined as dimensionless terms using Buckingham's Π theorem. Two mathematical models were developed in this study. In order to develop a model for integrated in-line emitters, experimental friction head losses data from 16 different drip irrigation pipes with above-mentioned spacings were used and the model developed accounted for 98·53% of the variation in the data. Another model developed was for predicting the friction head losses in laterals with on-line emitters. For the development of a model, experimental friction head losses data from six different drip irrigation pipes equipped with on-line emitters with above-mentioned spacings were used. The model developed for on-line emitters was able to explain the 98·76% of the variation in the data collected in the laboratory. The developed models in this study for in-line and on-line emitters were compared against the models available in the literature in terms of total friction head losses and lateral lengths. It was found that the total friction head loss differences between the developed model and the model existing in the literature were small and varied between −1·7% and +1·7% for in-line emitters while the same comparison for on-line emitters indicated a range between −0·9 and +1·9%. The results showed that the developed mathematical models may be used to determine the friction head losses in drip laterals with integrated in-line and on-line emitters placed on laterals at different spacings ranging from 0·2 to 1 m.

Application of Conditioner Solution by Subsurface Emitters for Stabilizing the Surrounding Soil

Poor uniformity of water application by subsurface drip irrigation has been examined and some explanations are suggested in this paper. Use of soil conditioners for soil structure stabilization around subsurface drip irrigation pipes was suggested by the authors and tested in the laboratory. The conditioners preserve the structure of existing aggregated and may effectively reduce soil clogging. A silt loam soil was uniformly packed in a 13 0.83 0.15 m box. Two holes were dilled in the box wall through which two emitters were inserted, one for applying solution of soil conditioner and one as a control. Stabilization was achieved by applying two types of polymer solutions differing by their molecular weights through an emitter buried in a silt loam soil. A measured water volume was injected through the emitters into the soil and, after 48 h following irrigation, the box was dismantled. Gravimetric soil moisture content and aggregate water stability were measured in vertical and horizontal distances from the emitter. The highest stabilizing effectiveness was obtained with a volume of 1.5 L polymer solution at 5 g / L concentration, which was applied to the soil at an initial moisture content of 13%. The volume of stabilized soil increased with the volume of applied solution, but the volume ratio of stabilized soil to applied solution decreased with the increase in solution volume. A polymer of relatively low molecular weight was found less effective since a large portion of the solution was consumed by fast penetration into soil aggregates without improving the soil structure. The proposed method offers a simple and easy means for preparing a stabilized soil envelope around subsurface drip irrigation pipes, which may improve the long-term performance and uniformity of the application of these systems. Yet for some of these aspects, further field evaluation is needed, since the results of the study are from a laboratory experiment limited to one soil only.

Design of Tapered Drip Irrigation Pipes Non-Uniform Slopes

Design of Tapered Drip Irrigation Pipes Non-Uniform Slopes

Selection of Drip Irrigation Pipe Size for Uniform Water Application

Selection of Drip Irrigation Pipe Size for Uniform Water Application

Liquid Flow-Control Device

A low cost valve, such as an emitter for controlling the flow from an aperture in a drip irrigation pipe, operates dynamically to maintain flow substantially constant across a wide range of pressures. A cylindrical valve seat mounted within the pipe aperture receives a valve member having a coaxial stem portion that extends through the valve seat to couple an external cap member. The interior end of the valve member comprises a diverging cone defined by integral and circumferentially separated leaf elements that engage a bearing surface of the valve seat at a root circumference when unstressed. Increasing water pressure within the pipe acts against the interior of the cone surface, distorting the leaf elements inwardly a proportional amount and shifting the valve member relative to the bearing surface through a selected limited operating range. The effective apertures between the leaf elements increase in length but decrease in width with greater pressure, providing an increasing impedance that maintains flow rate constant. The leaf elements are of selected stiffness and of relatively low friction material, and assume a stable pressure responsive position whether pressure is increasing or decreasing. The apertures between the leaf members are further shaped to provide an automatic purging flow when the pressure increases to or above a selected maximum.