MATHEMATICAL MODEL FOR PREDICTING VACUUM PRESSURE OF ONION SEEDS PRECISION SEEDER

Document Type : Original Article

Authors

1 Graduate Student, Dept. of Agric. Eng. Moshtohor, Benha Uni., Egypt.

2 Professor, Dept. of Agric. Eng. Moshtohor, Benha Uni., Egypt.

3 Director of The Agric. Eng. Res. Institute, ARC,Dokki , Giza , Egypt .

4 Lecturer, Dept. of Agric. Eng. Moshtohor, Benha Uni., Egypt.

Abstract

The main objective of this paper was to develop a mathematical model for predicting the optimum vacuum pressure of a precision vacuum seeder using onion seed properties, vacuum characteristics and the hole geometry of seed plate.  The onion seed properties were  linear dimensions (length (L), width (W) and thickness (T)), one thousand seed mass (m), seed cross sectional area (As), projected area (Ap), geometrical mean diameter (Dg), sphericity (f), seed density (ρs), repose angle (q), the dynamic coefficient of friction (m), terminal velocity (Vt) and the drag coefficient, (Cd).  The vacuum characteristics were the vacuum velocity in general flow (Vv), vacuum density at normal temperature (rv), vacuum pressure at normal temperature (Pv) and the Reynolds¢s number (NRe).  The hole geometry of seed plate were the effective hole diameter (Do), the radius in sink flow (R) and the conical entrance angle (a).
Experiments were carried out under laboratory and soil bin conditions.  Laboratory experiments were conducted to determine the onion seed properties.  Engineering calculations were performed for estimating the vacuum characteristics and also for calculating the hole geometry of seed plate.  On the other hand, soil bin tests were carried out to verify the accuracy of developed model at various levels of blower (vacuum pump) speeds using three seed plates with different hole diameters.  The blower speeds (BS) used were 4000, 4500, 5000 and 5500-rpm and the different hole diameters of seed plates were 0.8 mm, 1 mm and 1.2 mm.
Results indicated that the developed model could satisfactorily describe the parameters affecting on determining the vacuum pressure in the hole with correlation coefficients ranged from 0.97 to 0.99.  It also showed that the final model could be used for predicting the optimum vacuum pressure of a precision vacuum seeder of onion seeds with an efficiency of 0.99

Main Subjects

References

Bufton L P;  Richardson P; O'Dogherty M J (1974). Seed displacement after impact on a soil surface. J. Agric. Eng. Res. 19(4):327-338.
Fallak S S; Sverker P. (1984). Vacuum nozzle design for seed metering. Transactions of the ASAE., 688-696.
Giannini G R; Chancellor W J; Garrett R E (1967). Precision planter using vacuum for seed pickup. Transactions of the ASAE, 10 (5): 607-610, 614.
Guarella P; Pellerano A; Pascuzzi S (1996). Experimental and theoretical performance of a vacuum seeder nozzle for vegetable seeds. Agric. Eng. Res. 46, 29-36
Hammond J E (1965). Precision vacuum type planter head. USDA-ARS 42-115.
Holmes R G (1985). Seed planter, planter assembly and method of picking up and discharging single seeds. U.S. Patent No. 4,515,291.
Huang J (1999). "Speed of skydiver" (Terminal velocity)". The physics Factbook. Glenn Elter, Midwood High School, Brooklen Collage.
Karayel D; Barut Z B; Ozmerzi A (2004). Mathematical modeling of vacuum pressure on a precision seeder. Biosystems Engineering. 87 (4):437-444.
Moden W L; Jacobson R S (1973). Planter for nursery seedbeds. ASAE Paper No. 73-1545, ASAE, St. Joseph, MI 49085.
Mohsenin N N (1986). Physical properties of plant and animal materials. Gordon and  Breach     Science Publishers, New York. USA.
Rohrbach R P; Holmes R G (1970). Anew concept in seed metering. ASAE Paper Number 70-108. St. Joseph, MI: ASAE.
Shafii S; Holmes R G (1990). Air-jet seed metering, a theoretical and experimental study. Transactions of the ASAE., 33 (5): 1432-1438.
Short T H; Huber S G (1970). The development of planetary-vacuum seed  metering device.  Transactions of the ASAE 13(6):803-805.
Sial F S (1978). Design of nozzles for horticultural vacuum planters. Ph.D. Thesis, The Pennsylvania State University, University Park, 194 pp.
Sial F S; Persson S P E (1979). Optimum design of vacuum planter metering mechanisms. ASAE Paper No. 79-1075, ASAE, St. Joseph, MI 49085.
Sweetman I C (1957). A suction operated precision planter. N. Z. J. of Sci. and Tech. A38(6):577-582.
Walters J  (1971). Precision sowing of forest tree seed for container planting. Transactions of the ASAE 14(6):1136-1138.
Wanjura D F; HudspethE B (1969). Performance of vacuum wheels metering individual cotton seeds. Transactions of the ASAE 12(6):775-777.
Misr Journal of Agricultural Engineering
Volume 26, Issue 4
October 2009
Pages 1776-1799

Files

Share

How to cite

Statistics