Research And Design On Automatic Test System For Micro-irrigation Emitter

An agricultural micro-irrigation emitter is a key device for micro-irrigation, and the hydraulic performance of the micro-irrigation emitter is an important index sign in measuring the quality of micro-irrigation system, it is also an important parameter of the micro-irrigation system design. Studies have shown that the a lot of factors will contribute to the quality of micro-irrigation, which include: hydromechanics variation of micro-irrigation system; manufacturing deviation coefficient of emitter, the blockage degree of emitter, the arrangement and combination of emitters etc. Therefore, whether for producing of new products lines or for designing of micro-irrigation system, testing and determination of their hydraulic performance are necessary. But now in China, testing means for micro-irrigation products are very few. Even there are some kinds of testing equipments, but most of them are manual operated, with large human error, low precision and low speed. It is difficult for them to carry out product quality inspection and supervision effectively. Therefore, it is surely necessary for us to establish a laboratory to automatic test the hydraulic performance of micro-irrigation emitters. Which will play an important guidance role for secondary research and development, engineerng design and application in facilitity agriculture field. In this paper, the main test functions of this automatic test system for micro-irrigation emitters are, on the basis of some related national industry standards, making test of flow unifirmity, relationship between pressure and flow and pressure tolerance and so forth for the 25 weighing units and a pressure unit. Its innovative point is that non-standard test, that is, under the conditions in the laboratory and by equipment adjustment, to test hydraulic performance of micro-irrigation emitters by the method of samples serial water supply. By simulation the real operating condition of field water-saving irrigation, it can test the hydraulic performance of micor-irrigation and drip-irrigation pipeline at layout and design length, set up a initial relation among pressure, flow, installation method, combination spacing, wet pitch radius (range) and spray uniformity. The research will provide essential theoretical basis and technical support for our research and development on water-saving irrigation projects and for compatible design for water-saving irrigation engineering. The research task is consists of many subjects such as data acquisition and control theory, micro-irrigation technology, analog and digital electronics, fluid mechanics, mechanical design, and so forth, and these subjects are well crossed and integrated. The research subject includes mainly the following areas:1. Research and test on test system for micro-irrigation emitters are made, a complete set of test system for micro-irrigation emitters was manufactured, and comparation tests and study to manual testing method were made. The study results showed that this test system is superior to manual testing methods both at the experimental efficiency and at precision.2. By test method of using weighing sensors for detecting water spray volume of micro-irrigation emitters to complete the design of automatic data data acquisition unit for spray volume. The results showed that the use of weighing sensors for flow data acquisition is simple in structure, easy to use and easy to connect with single-chip data acquisition system, which further imporove the automatic level for testing of micro-irrigation emitters.3. The system is capable of making self communication inspection of weighing and pressure units, therefore problems can be found out and solved on time. A method is applied to eleminate the effect of different pressure at upstream and downstream outlets of capillary micro-irrigation emitters on irrigation uniformity. The results showed that effects of pressure difference at upstream and downstream outlets of capillary micro-irrigation emitters on irrigation uniformity is eleminated, and test purpose is arrived at.4. Flow and uniformity testing. When you make flow uniformity test on the basis of relevant micro-irrigation standards, the measuring points may be chosen at your free, also the test durations can be chosen at your free according to the flow volume of emitters. Not only can you test only once and then process the data, but also can you test twice (as the standard requested) and take the average for data processing. After testing, the average outlet flow and coefficient of flow variation will be arrived at, and all the measuring points can be sorted by outlet flow.5. Test on relationship of pressure vs. flow. Not only can you test only once and then process the data, but also can you test twice and take the average for data processing. Upon test completion, you can give a relationship formula between pressure and flow, and a curve of pressure vs. flow.6. The system can make pressure tolerance test at different pressures and durations on the test piece.Finally, the paper makes some suggestions and proposes on the further study of this automatic test system on micro-irrigation emitters.