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  • ThesisItemOpen Access
    Evaluation and modification of spike-tooth and rasp-bar type paddy threshers
    (Department of Farm Power Machinery and Energy, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1993) Sailaja, L; KAU; Sivaswami, M
    The field survey conducted on the threshing practices of paddy in Kerala revealed that the hand beating method which is more common in southern part of Kerala needed 154.7 man h/ha with an average output of 18.5 kg/man h requiring an amount of Rs. 823.5/ha whereas, in central Kerala the feet rubbing method required Rs. 1599.0/ha and needed only319.8 man h/ha with an average output of 11.27 kg/man h. The 8 hp axial flow spike-tooth type and 10 hp flow through rasp-bar type threshers were evaluated and found an average output of 50 kg/hp h and 107 kg/hp h respectively. The maximum threshing efficiency of 98.77 per cent and 97.44 per cent were recorded for the flow through rasp-bar thresher during ‘virippu’ and ‘mundakan’ seasons compared to only 95.50 per cent and 94.49 per cent respectively for spike-tooth thresher. The high moist and long paddy crops used to stick and choke in between cylinder and concave clearance and hence the concave was successfully improved to eliminate these problems. The improved concave also improved the output to 1081 kg/h and 1122.6 kg/h with an increase of 9.25 per cent and 4.27 per cent respectively during ‘virippu’ and ‘mundakan’ seasons. A maximum output of 305.7 kg/hp h was obtained for the 1 hp prototype thresher with the rasp-bar cylinder compared to the output of 256.5 kg/hp h for spike tooth cylinder. The cost of operation for the commercially available axial flow through rasp-bar threshers was found to be Rs. 400/ ha and Rs. 207/ ha respectively. The rasp-bar thresher with improved concave could save an amount of Rs. 616.5/ha which accounted to a net saving of 74.9 per cent in the cost of threshing compared to the hand beating method.
  • ThesisItemOpen Access
    Development and testing of a manually operated paddy dibbler
    (Department of Farm Power Machinery and Energy, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1992) Bini Sam; KAU; Sankaranarayanan, M R
    A manually operated three row paddy dibbler for dry sowing was developed and tested at Kelappaji College of Agricultural Engineering and Technology, Tavanur. The metering mechanism employed in this dibbler was unique in design. The machine consists of seed box, roller with metering mechanism, seed tube with furrow opener, frame, handles and marker. When the dibbler was operated for dibbling, the roller passing vertically through the centre of box would move upward by the soil pressure against the spring pressure. As the roller moved upward, the portion of the roller having the vertical slot would come in contact with seeds and the seeds were moved and carried to this slot. When the equipment was taken out from the soil, the soil pressure on the roller was released and due to the spring pressure the roller moved downward and the seeds carried in the slot were released and would fall through the seed tube by gravity in to the soil. During the operation of the equipment due to the downward travel of the roller and seed tube the seed hole was created for dropping the seeds. The covering of seeds with soil was carried out automatically when the equipment was taken out from the soil. The number of seeds dropped was in the range of 4 to 6 per hill. The area covered by the dibbler was 0.022 hectare per hour. The field efficiency obtained was 68.68 per cent. The mechanical damage was 4.84 per cent. The percentage losses of seeds after germination was 9.52. The fabrication cost of the dibbler including cost of material was Rs. 800/-. The operating cost of the dibbler was Rs. 16/- per hour. The cost of sowing one hectare of land was Rs. 717/- while for manual dibbling the cost of sowing was Rs. 979/- per hectare. Moreover manual dibbling is done in a bending position which is arduous to the farmer. But in the present design of dibbler, a suitable handle is provided which ensure easy and comfortable operation in a straight posture. The equipment can be fabricated locally with readily available materials and can be easily maintained by small farmers.