FRICTIONAL PROPERTIES OF SELECTED SEEDS

K e y w o r d s: physical attributes, coefficient of external friction, relation. A b s t r a c t The thickness, width, length and weight of five seed species (buckwheat, vetch, pea, lupine and faba bean) and their external friction angle were determined on two types of surfaces -steel and rubber. The experiment was performed with the use of a an inclined plane with an adjustable angle of inclination that measures the angle of external friction and the time taken by seeds to travel a given distance, which supports the determination of the coefficient of kinetic friction. The measured parameters were used to calculate arithmetic and geometric mean diameter, aspect ratio and sphericity index. The dimensions, weight and the calculated indicators of the examined seeds did not significantly affect their coefficients of static and kinetic friction or their coefficients of rolling resistance and rolling friction. The studied parameters were largely influenced by the type of friction surface, and significantly lower average values were reported for steel than rubber. In the studied seed species, the static friction coefficient was determined in the range of 0.187 to 0.582, kinetic friction coefficient -0.134 to 0.479, rolling resistance coefficient -0.148 to 0.529 and rolling friction coefficient -0.29 to 1.80 mm. Symbols: D a -arithmetic mean diameter, mm, D g -geometric mean diameter, mm, m -seed weight, mg f 1 , f 2 -coefficient of rolling friction of seeds on steel and rubber, respectively, mm, r -radius of a rolling seed, mm, R -aspect ratio, %, S -travel distance of the particle, m, t -time required by the particle to travel distance, s, T, W, L -seeds thickness, width and length, mm, x, SD -average value and standard deviation of trait, x min , x max -minimum and maximum value of trait, α -angle of external friction of seeds, o , α s1 , α s2 -angle of static friction of seeds on steel and rubber, respectively, o , α t1 , α t2 -angle of rolling friction of seeds on steel and rubber, respectively, o , μ -coefficient of external friction of seeds, Correspondence: Zdzisław Kaliniewicz, Katedra Maszyn Roboczych i Metodologii Badań, Uniwersytet Warmińsko-Mazurski, ul. Oczapowskiego 11/B112, 10-719 Olsztyn, phone: +48 89 523 39 34, e-mail: [email protected] μ k1 , μ k2 -coefficient of kinetic friction of seeds on steel and rubber, respectively, μ s1 , μ s2 -coefficient of static friction of seeds on steel and rubber, respectively, μ t1 , μ t2 -coefficient of rolling resistance of seeds on steel and rubber, respectively. Φ -sphericity index, %

A Theoretical Analysis of Cereal Seed Screening in a String Sieve

The conditions of the screening process in a fixed string sieve designed by the author have been formulated. The string sieve was designed for separating seeds of 5 cereal species (wheat, rye, barley, oats and triticale). The width of the separating groove was set at 1 mm at the beginning of the screen and 5 mm at the end of the screen. It has been assumed that seeds have a spheroidal shape and that their motion is initiated by positioning the string sieve at an appropriate angle. The results of a theoretical analysis revealed that at the given parameters of a string sieve, the above angle is determined only by the thickness and width of separated seeds. The sieve’s angle of inclination should be set at 45° to propel seeds into motion and at 50° to ensure the continuity of the screening process. Such a large setting angle is not recommended because it increases the sieve’s height and deteriorates the quality of the separation process. The problem can be solved by setting the separator bucket into motion and separating seeds at a small inclination angle of the string sieve

Wpływ stopnia zanieczyszczenia surowca ziaren gryki na czystość produktu po czyszczeniu w tryjerze z wgłębieniami kieszonkowymi

This study analyzed four mixtures of buckwheat nutlets and wild radish siliques with impurity content (wild radish siliques) of 2.5, 5.0, 7.5 and 10.0%. Buckwheat nutlet yield, the efficiency of wild radish silique removal, the efficiency of mixture separation and product purity were determined at two depth settings of indented pockets (2.4 and 2.8 mm), three factors of static load of the cylinder with the mixture (0.1, 0.2 and 0.3 of full load) and five angles of the working edge of the trough (10, 20, 30, 40 and 50°). The obtained results indicate that the impurity content of raw material significantly affects the purity of the separated product.Do badań wykorzystano cztery mieszaniny ziaren gryki i łuszczyn rzodkwi świrzepy o udziale: 2,5, 5,0, 7,5 i 10,0% składnika zanieczyszczającego - łuszczyn rzodkwi świrzepy. Wyznaczano uzysk ziarna gryki, skuteczność wydzielania łuszczyn rzodkwi świrzepy, skuteczność rozdzielania mieszaniny i czystość produktu na dwóch głębokościach wgłębień kieszonkowych (2,4 i 2,8 mm), przy trzech wskaźnikach statycznego obciążenia cylindra mieszaniną (0,1, 0,2 i 0,3 pełnego obciążenia) oraz pięciu kątach ustawienia roboczej krawędzi rynienki (10, 20, 30, 40 i 50°). Stwierdzono, że stopień zanieczyszczenia surowca wpływa istotnie na czystość produktu czyszczenia

Two mathematical formulas for assessing seed separation efficiency

Two mathematical formulas for assessing the efficiency of seed mixture separation were analyzed. Increases in the crop seed yield and the efficiency of impurity separation were accompanied by higher seed separation efficiency regardless of the adopted formula. One of the examined formulas carried more information, and it could be used to determine the improvement in the purity of the separated product relative to the raw material. The difference in the analyzed formulas’ ability to determine the efficiency of seed separation was minimized when the separation process was more efficient, i.e. when the value of partial indicators of separation efficiency was closer to 1. Both formulas could be successfully used to describe seed separation efficiency because in most practical applications, the error generated by the evaluated formulas did not exceed 1.5%

String sieve: design concept and parameters

This paper presents the design concept and the parameters of a new device for cleaning and-or sorting seeds and grain produced in a conventional farm. The discussed device is a string sieve where the groove between adjacent strings is minimal at the beginning of the screen and increases towards the end of the screen. The proposed sieve poses an alternative to a screen separator comprising a set of differently-sized mesh screens with longitudinal openings. In view of the average size of farm-produced seeds, the width of the separating groove should be set at 1mm at the beginning of the screen and 11 mm at the end of the screen. In sieves not designed for grading large seeds or vetch seeds, the width of the separating groove can be set at 1 mm and 5 mm, respectively

Separation efficiency for the mixture of corn seeds and buckwheat nuts in a trieur with pocket pits

Określono wpływ głębokości wgłębień kieszonkowych, wskaźnika statycznego obciążenia cylindra mieszaniną i kąta ustawienia roboczej krawędzi rynienki na uzysk orzeszków gryki, skuteczność wydzielania ziarniaków zbóż (pszenicy, żyta, jęczmienia i owsa) oraz skuteczność rozdzielania mieszaniny. Stwierdzono, że zastosowanie tryjera z wgłębieniami kieszonkowymi pozwala na poprawę czystości produktu czyszczenia, ale nie w takim stopniu, aby można go było uznać za produkt bezglutenowy.The research allowed to determine the impact of pocket pits depth, the index of cylinder static loading with the mixture, and chute working edge setting angle on buckwheat nuts yield, release efficiency for corn seeds (wheat, rye, barley and oat), and mixture separation efficiency. It has been observed that using a trieur with pocket pits allows to improve cleaned product purity, however not to the extent sufficient to qualify it as a gluten-free product

Analysis of relationships betwen mass and basic dimensions buckwheat and wild radish segments

W pracy przedstawiono metodykę i wyniki pomiarów grubości, szerokości i długości oraz masy ziaren gryki i łuszczyn rzodkwi świrzepy. Określono związek korelacyjny i matematyczny między przyjętymi cechami. Uzyskano równania, które można wykorzystać zarówno do budowy matematycznych modeli ziaren gryki i segmentów łuszczyn rzodkwi świrzepy, jak i matematycznych modeli procesów rozdzielczych.The methodology and results of measurements of thickness, width and length as well as mass of buckwheat and wild radish seeds in work were introduced. Between received features, the correlation and mathematical relationships were qualified. The obtained equations can be used to building of mathematical models of buckwheat and wild radish segments seeds as well as to the mathematical modelling of cleaning processes

Variability analysis and correlation of selected physical properties of black alder seeds

Dokonano pomiarów prędkości krytycznej unoszenia, grubości, szerokości, długości, kąta tarcia ślizgowego i masy oraz wyznaczono współczynniki sferyczności nasion olszy czarnej, zebranych z 3 różnowiekowych drzewostanów nasiennych. Do opisu i analizy cech wykorzystano analizę wariancji z klasyfikacją pojedynczą, korelację oraz regresję jednej zmiennej i wielu zmiennych.Measures of critical speed of lifting, thickness, width, length, sliding friction angle and mass were taken. Moreover, spherical coefficient of black alder seeds collected from three seed tree stands of different age was determined. The analysis of variance with single classification, correlation and regression of one variable and many variables was used for description and analysis

Design concept and parameters of a conical bar separator

The process of adapting a screen separator to seeds of a given species and variety requires a corresponding set of replaceable screens. Screen replacement is a time-consuming process. Screens are often selected from the available size range, therefore, cleaning and separation processes are not always optimized. This study proposes a design concept of a new device for cleaning and separating seeds, which features a conical bar screen that rotates around its own axis. The screen has grooves whose width is smallest at the beginning of the screen and increases along the screen surface. Seeds can be sorted into various size fractions by changing the position of collecting buckets under the screen. The functional parameters of the separating device were designed based on a review of publications describing the size of the most popular agricultural seeds. The basic geometrical relationships in the proposed conical bar screen were described. The geometrical parameters of the screen were selected on the assumption that the radius at which bars are fixed to the screen can range from 200 mm to 400 mm and that bar diameter can range from 5 mm to 10 mm. Two variants of the device were proposed as a replacement for one universal separating screen. The first variant will be used to sort small seeds, including seeds of small-seeded legumes, seeds of major cereal species and medium-sized seeds with dimensions similar to cereal seeds, whereas the second variant will be applied to separate large seeds, including seeds of large-seeded legumes and plumper seeds from the medium-size fraction. The width of grooves at the beginning and end of the screen should equal 1 mm and 5 mm in the first variant and 2.5 mm and 13 mm in the second variant, respectively