Study of properties of lentils and weed of Euphorbia helioscopia and the parameters affecting the separation that from lentils by gravity table separator

IntroductionLentil (Lens culinaris Medik) is an important and highly nutritious crop belonging to the family of legumes. Lentil is cultivated worldwide but competition with weeds is a problem affecting production and can reduce performance by more than 80%. Euphorbia helioscopia weed is a major weed in lentil cultivation. In the first place, it is necessary to have a thorough and comprehensive knowledge about the characteristics of the lentils and the accompanying impurities to mechanize the process of automatizing activities related to lentils such as warehousing, sorting (grading), packaging, transportation and other activities. On the other hand, physical and aerodynamic properties of agricultural products were always regarded as significant because those are the basis for designing and construction of agricultural and machineries, transport equipment, grading and processing of agricultural products. Designing agricultural machineries was impossible without regarding these parameters, or it would lead to weak results. The study of physical properties and separation of Euphorbia helioscopia weed from lentil by a gravity separator is of extreme importance. Since no study has been done to date, in this work physical properties of lentil and Euphorbia helioscopia weed are investigated. Moroever, the effects of different parameters of a gravity separator and their influence on the separation of Euphorbia helioscopia weed from lentil seeds are evaluated.
Materials & MethodsIn the present research, lentil samples were taken from farms in Ardebil province (Bileh-Savar cultivar) and transferred to the seed technology laboratory at the University of Tehran. In addition, some physical properties of lentil and weed of Euphorbia helioscopia including mass of 1000 seeds, volume, true and bulk densities and porosity and static coefficient of friction (two types of friction surface: galvanized iron sheet and particle board) were measured. In addition, in this research, a gravity separator apparatus was used for separating weed of Euphorbia helioscopia from lentils. A Laboratory Gravity Separator Type LA-K (Westrup A/S Denmark) was used to separate Euphorbia helioscopia weed from lentil seeds. Influence of parameters of machine table (longitudinal and latitudinal slopes, oscillation frequency and amplitude and velocity of air) have been studied for obtaining of maximum separation of weed of Euphorbia helioscopia from lentils. Data analysis and comparison of means were done by using MSTAT-C software and Duncan's Multiple Range Test.
Results & DiscussionThe obtained results show the main effects oscillation of frequency, latitudinal slope, and longitudinal slope, the mutual binary effect of latitudinal and longitudinal slope, the mutual binary effect of the latitudinal slope and the frequency of oscillation were significant at a 1% and the mutual binary effect of the longitudinal slope and the frequency of oscillation significant at a 5%. However, the mutual triple effect of oscillation frequency, longitudinal slope, and latitudinal slope was not significant. Furthermore, results showed that increase of latitudinal slope of table and increase of longitudinal slope from 1.25 to 2 degrees increased separation of weed of Euphorbia helioscopia from lentils. The results of the experiment showed that the separation of Euphorbia helioscopia weed from lentils get to maximum 14.2 percent .After determining most suitable amplitude and velocity of air, using data from the longitudinal slope, latitudinal slope and dimensionless number was used to calculate mathematical relations of separation percentage of Euphorbia helioscopia weed from lentil clumps using Datafit software.
Conclusion1. Physical properties obtained for lentil were as weight of 1000 seeds (57.03 g), true density (1.214 g cm-3), bulk density (0.782 g cm-3), coefficient of static friction (galvanized iron sheet (0.394 degrees) and particle board (0.37 degrees)), porosity (35.59 %), and the Euphorbia helioscopia weed including weight of 1000 seeds (5.69 g), true density (0.857 g cm-3), bulk density (0.538 g cm-3), coefficient of static friction (galvanized iron sheet (0.32 degrees) and particle board (0.40 degrees)), porosity (37.2 %).
2. Increased latitudinal slope of the table from 0.5° to 1° and longitudinal slope of the table from 1.25° to 2° result in increased separation percentage of wild oat weed from lentil seeds.
3. The results demonstrated that at settings of longitudinal slope of 2°, latitudinal slope 1°, and frequency of oscillation 400 cycles min-1, the maximum separation was 14.2%. In this case, the output lentil seeds contained the least amount of wild oat weeds.