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ThesisItem Open Access Development and evaluation of process protocol for vacuum fried carrot chips (Daucus Carota L)(Department of Processing and Food Engineering, KCAET, Tavanur, 2021) Babu, P; KAU; Rajesh, G KCarrots are highly nutritious vegetable, which can be consumed in raw and processed form throughout the world. Carrot plays a vital role in the development and protection of human body. Carrot contains vitamins viz., B1(Thiamine), B2(Riboflavin), B6(Niacin) and B12 (Cobalamin) besides rich in source of βcarotene and dietary fibre which are helpful to prevent cancer and other dreadful diseases occur in human body. In Kerala state, carrot production is very limited, but its consumption is more. The postharvest losses of carrot were estimated as 18- 20%. The development of value-added products from carrot was an idealistic solution to reduce the postharvest losses by adopting new processing technologies. At present, due to consumer’s awareness, there is a lot of demand for healthy and tasty snack products with less oil content which provide good health. In this context, investigation on processing technologies focus on producing high quality fried products with less oil content and good textural property. The technology of vacuum frying is a best option for the production of novel snacks which fulfil the consumers demand and meet nutritious requirements. Vacuum frying is a novel technology, in which the food is heated under lower temperature and pressure(<6kPa). Vacuum frying lowers the water activity, oil content, retains the color and preserve nutrients in the fried product. The batch type vacuum frying system consists of two chambers viz., frying chamber (3kg capacity) and oil storage chamber (30-35L capacity). The refined palm oil was used for vacuum frying and de-oiling was done at 1000 rpm for 10 min. After every batch of vacuum frying, the oil was collected for quality analysis. Prior to the research, the physico-chemical properties of raw carrot (Ooty-1) was determined. The pre-treatments viz., blanching, blanching cum drying, blanching cum freezing, freezing and gum coating were optimized based on the quality of vacuum fried carrot chips. The freezing pre-treatment obtained the best results among other pre-treatments in terms of less oil content (14.48 %), water activity (0.214), moisture content (2.67%), hardness (1.282 N) and red color retention of a* value (22.85). The standardization of process parameters were done using RSM (CCRD) based on the quality characteristics of VF-carrot chips. The process parameters seected in this study were frying temperature (100,110 and 1200C), frying pressure (11,13 and 15 kPa) and frying time (16,18 and 20 min). The optimum operating conditions of vacuum frying viz., frying temperature, vacuum pressure and frying time were found to be 100°C, 11 kPa and 16 min respectively. At optimum operating conditions of 100°C, 11 kPa and 16 min, the quality parameters were oil content (11.31%), bulk density(0.873 g/cm3 ), true density(1.714 g/cm3 ), moisture content(3.28%), water activity (0.384), hardness (1.31 N),thickness expansion (60.42%), L*(43.48), a*( 14.36) b*(28.12) and energy content(1021 KJ/100g). Packaging and storage studies were conducted for the treatments which had high sensory score. The laminated aluminium flexible pouch with N2 gas filling was found to be the best packaging technique to enhance the shelf life of VF carrot chips to a storage period of 4 months. The oil quality parameters viz., total polar compounds (TPC), viscosity, peroxide, free fatty acids (FFA) etc were within the allowable limits even after 40 batches of vacuum frying. The total production cost of 1kg of vacuum fried carrot chips was found to be Rs. 355/-.ThesisItem Open Access Investigations on high rate anaerobic bioreactor for energy production from rubber latex processing effluent(Department of Farm Machinery and Power Engineering, Kelappaji College of Agricultural Engineering and Technology,Tavanur, 2020) Megha, A S; KAU; Shaji James, PAgro-processing industries often contribute significantly in pollution due to discharge of untreated effluents. By anaerobic digestion of these organic effluents, methane rich gas can be produced which is suitable to generate electricity and process heat. But conventional biogas plants are slow in operation with long hydraulic retention times of 35 to 40 days which necessitates large digester volumes. So, anaerobic digestion of high volume agro-processing effluents is feasible only through high rate bioreactors which can reduce hydraulic retention time to few hours. Rubber latex processing effluent (RLPE) is a dilute waste water for which high rate anaerobic treatment can be an affordable technology. Hence, an investigation was taken up to study the performance of Up-flow Anaerobic Hybrid Bioreactor for energy conversion of rubber latex processing effluent (RLPE). Physico-chemical characteristics of RLPE samples were tested and found that RLPE was a dilute waste water with pH in the acidic range. BOD: COD ratio of 0.44 obtained in this study showed good biodegradability of RLPE. A batch anaerobic digestion study was conducted as a preliminary experiment to investigate the biomethanation characteristics of RLPE. The experiment consisted of four treatments having different composition of RLPE with inoculums replicated thrice. This study could prove that RLPE could be subjected to biomethanation and cow dung slurry can be used as inoculum. Even at a lower inoculum: substrate ratio of 1:2, the system could be started up yielding substantial amount of biogas coupled with good TS reduction. Performance of field scale Up-flow Anaerobic Hybrid Bioreactors (UAHBR) was assessed by operating them at different HRTs of 10, 7, 5, 3 and 2 day. During the study an interruption of 2 months in operation occurred due to shut down of the processing unit due to Covid 19. After interruption of 2 months reactor recovered within one month and it proved that hybrid bioreactor could be restarted easily after a shutdown for few months. Reactor was stable in operation during 10, 7, 5, 3 and 2 day HRTs and exhibited good process efficiency with better pollutant reduction and biogas production. Performance was seen deteriorated beyond 5 day HRT. The bioreactors were operated successively at reduced loading rates corresponding to the longer HRTs after reaching the shortest HRT of 2 day. It was observed that there was no considerable difference in daily biogas production with the earlier values obtained during the progressive decrease in HRT. This revealed that the bioreactors would have achieved the maximum possible microbial population already and there was no further improvement in performance on further passage of time. The performance parameters obtained in the investigations with field scale reactors were used for evolving guidelines to design a full scale anaerobic bioreactor. The UAHBR performance was quite satisfactory at 5 day HRT with respect to pollutant reduction as well as energy production. Hence as criteria, full scale plant was proposed to be operated at 5 day and the corresponding reactor volume was 27 m 3 with 7.2 m 3 gas holder volume. The biogas expected to be produced from the full scale plant can be used in a biogas fired rubber sheet dryer which can save about 500 kg of fire wood per day currently used for drying rubber sheets.ThesisItem Open Access Investigations on soil crop and machine parameters towards the development of a root crop harvester(Department of Farm Machinery and Power Engineering, Kelappaji College of Agricultural Engineering and Technology,Tavanur, 2020) Basavaraj; KAU; Jayan, P RThe tractor drawn root harvester was designed and developed by considering soil, crop and machine parameters and performance evaluation of the machine was carried out in the experimental area at KCAET, Tavanur and different farmers’ fields at Palakkad and Thrissur districts. The developed machine mainly consists of main frame, power transmission system, digging and soil separator units. The effect of three blade geometries viz., straight edge, V-type and crescent blades at three rake angles of 15, 20 and 25 deg. and at three forward speeds of 1.5, 2.0 and 2.5 km h-1 for the digging unit of the harvester were evaluated in terms of draft, digging efficiency, per cent damage of tuber/rhizome and fuel consumption of tractor mounted harvester for harvesting coleus, ginger and turmeric. The best optimal condition was observed at a forward speed of 2.0 km h-1 with 20 deg. rake angle for V-type blade. The soil separator unit of the harvester was evaluated along the digging operation. The soil separator unit was tested with different operational parameters viz., diameter of crank 40, 60 and 80 mm and spring tension 800, 1200 and 1600 N m-1. The best optimal operational conditions were observed at a spring tension of 1600 N m-1 with 80 mm diameter of crank. The maximum draft of 2009.52 N was recorded in straight blade while the minimum of 1418.66 N was observed in V-type blade. The maximum digging efficiency of 99.89 per cent was noticed in V-type blade, whereas the lowest of 84.15 per cent in straight edge blade. The least damage coleus of 0.59 per cent was observed in V-type blade whereas highest of 5.5 per cent was obtained in crescent blade. Among the different type of blades tested, the less fuel consumption of 3.80 l h-1 was noticed for V-type blade, whereas the maximum of 4.98 l h-1 for straight edge blade. In the case of harvesting ginger, the maximum draft of 2176.33 N was recorded in straight edge blade while the minimum of 1374.31 N was observed in V- type blade. The maximum digging efficiency of 99.57 per cent was noticed in V-type blade, whereas the lowest of 80.40 per cent in straight edge blade. The least damage coleus of 0.86 per cent was observed in V-type blade whereas highest of 6.05 per cent was obtained in crescent blade. Among the different type of blades, the less fuel consumption of 3.74 l h-1 was noticed for V-type blade, whereas the maximum of 5.19 l h-1 for straight edge blade. In the case of harvesting of turmeric, the maximum draft of 2192.08 N was recorded in straight edge blade while the minimum of 1390.06 N was observed in V-type blade. The maximum digging efficiency of 99.50 per cent was noticed in V-type blade, whereas the lowest of 81.91 per cent was recorded with the straight edge blade. The least per cent damage coleus of 0.74 per cent was observed in V-type blade whereas highest of 7.3 per cent was obtained in crescent blade. Among the different type of blades, the less fuel consumption of 4.0 l h-1 was noticed for V- type blade, whereas the maximum of 5.57 l h-1 for straight edge blade. The field capacity of the machine for coleus, ginger and turmeric were 0.15, 0.16 and 0.16 ha h-1 respectively and the field efficiencies were 86.11, 88.89 and 88.89 per cent respectively. The soil separation indices of root crop harvester for coleus, ginger and turmeric were found out as 82.71, 73.22 and 68.82 per cent respectively where as the conveying efficiencies were 90.70, 87.55 and 89.71 per cent respectively. The estimated cost of the prototype tractor drawn root crop harvester was as Rs. 60,000. The cost of operation was found out as Rs. 767.57 per hour. The saving in cost over root crop harvester for three root crops was 89 per cent. The machine has BEP of 40 h, PBP as 1.5 years and BCR as 10.7.ThesisItem Open Access Optimization of agronomic resources for maximizing grain and mill yield of rice(Department of Agricultural Engineering, Indian Institute of Technology, Kharagpur, 1976) Kannan, Mukundan; KAU; Pande, H KAn investigation was planned during the main growing season, i.e., ‘aman’ (June to November ) to find out the optimum levels of the major inputs for rice cultivation such as nitrogen, phosphate, and water, associated with the management practices like optimum time of harvest, in order to maximize production and to obtain quality paddy which, when processed, should give a high quality rice and thereby high economic return. Keeping the above points in view, four field experiments were conducted during two consecutive ‘aman’ seasons of 1972 and 1973 in a cultivators’ field at abhoy Ashram, Balaramapur which is located about 3 km south – east of the Institute. The farm soil was silty – clay – loam, having a pH of 8.1. The experiments were conducted with the high – yielding rice variety IR 22 to study its performance under three levels each of nitrogen, phosphate and submergence and laid out in 3 x 3 x 3 confounded design. Nine additional plots to accommodate ‘o’ levels of nitrogen and phosphate were included for fitting production functions. In the first year of experimentation, the nitrogen and phosphate levels were 60, 120 and 180 kg/ha and 30, 60 and 90 kg/ha respectively. In the second year, the levels were 60, 90 and 120 kg N/ha and 30, 45 and 60 kg P2O5/ha. The modification in the levels of nitrogen and phosphate, in the second year, were made on the basis of the findings of the first year of experimentation. In both the years, the levels of submergence were kept constant, i.e., 0 – 5 cm, 5 + 2 cm, and 10 + 2 cm. For finding out the optimum grain moisture at harvest, suitable for higher milling yield, the crop was harvested at 25.5 – 22.5, 22.5 – 19.5 – 16.5 and 16.5 – 13.5 per cent grain moisture. The optimum levels of each input for maximizing grain yield and head yield were found out by fitting production functions. To identify a suitable variety under a specific management of production and processing, four high yielding rice varieties – Sona, Jayanthi, Pankaj and IR 22 were grown in ‘aman’ season of 1972 and 1973 with similar levels of nitrogen and phosphate as mentioned in Experiments 1 and 2; an additional treatment, with nitrogen and phosphate at ‘o’ level was also included. These experiments were laid out in 4 x 4 x 4 confounded design. The crop was grown under continuous submergence of 5 +2 cm and was harvested at grain moisture content ranging between 19.5 and 16.5 per cent. Treatment wise experimental details and the salient findings are given in the following pages. Positive response with reference to grain yield, total mill yield and head yield of variety IR 22 was noted up to 90 kg N/ha and 45 kg P2O5/ha. Further increase in nitrogen and phosphate levels to 120 kg/ha and 60 kg/ha respectively did not and its percentage was minimized by harvesting the crop above 19.5 per cent grain moisture or between 26 and 30 days after flowering. However, by increasing the level of nitrogen from 90 to 120 kg/ha and 120 to 180 kg/ha, the head yield and its recovery percent was less affected even when the crop was harvested with some delay, i.e., between 19.5 and 16.5 per cent grain moisture or between 35 and 37 days after flowering. The influence of phosphate on grain yield and milling quality, particularly head yield recovery percentage, was more pronounced when considered in combination with grain moisture at harvest. A suitable water management practice, of growing the crop with shallow submergence of 5 + 2 cm was found beneficial in increasing the yield as well as the milling and head yields. The influence of submergence on the head yield recovery percentage was, however, not to the same extent as that of nitrogen and grain moisture at harvest. On fitting the function, for variety IR 22, it could be ascertained that maximum grain yield to the extent of 5112 kg/ha can be attained with the optimum levels of 119 kg N/ha, 59 kg P2O5/ha, 149 cm of water and 22.4 per cent grain moisture at harvest which corresponded to harvesting the crop about 30 days after flowering. On the other hand, maximum head yield to the extent of 3562 kg/ha can be attained with the optimum levels of 124 kg N/ha, 51 kg P2O5/ha, 159 cm of water and around 26 per cent grain moisture at harvest which corresponded to harvesting the crop about 26 days after flowering. The grain yield and consequently, the gross and net returns were maximum under the same levels of nitrogen, phosphate, submergence and grain moisture at harvest. However, from an assessment of rough rice and polished rice along with broken, bran and husk, it was ascertained that the increase in net return to the extent of 984 k/ha was possible only by processing the rough rice. The positive response in grain yield of all the varieties was found only up to 90 kg N/ha and 45 kg P2O5/ha. In varietal comparison, grain yield, mill yield, head yield and net return were found to be maximum in case of the variety Pankaj, amounting to 5192 kg/ha, 3768 kg/ha, 3027 kg/ha and 1716 Rs/ha respectively. The variety Pankaj was followed by IR 22, Sona and Jayanthi in order. However, in milling quality, particularly head yield recovery percent, IR 22 was found superior to all the other varieties. Further, the variety IR 22, with along and slender grains, proved superior in quality to Pankaj, with long and bold grain. The former, eventually, has higher market value that brought higher return. These characteristics in IR 22 narrowed the difference in profit, when compared to Pankaj, though the latter has significantly higher grain yield the additional net return over milled rice was estimated at 877 Rs/ha in case of IR 22 and 833 Rs/ha in case of Pankaj. The agro – climatic conditions of this region of West Bengal, where rice is the only crop during ‘aman’, provide better prospects for cultivation of variety IR 22 as well as Pankaj. In quality criteria as well as growing period, IR 22 may prove superior to Pankaj. Their cultivation for higher yield and quality rice is possible only through suitable levels of fertility and water inputs as well as management input which includes the timeliness of operations, particularly harvesting, because it has a greater impact on the final outturn of the produce as quality rice.ThesisItem Open Access Design and development of a propeller pump(Department of Agricultural Engineering, College of Horticulture, Vellanikkara, 1984) Sasi, K; KAU; Remadevi, A N“Petti and Para” a crude form of Axial flow pump is used in Kerala for dewatering agricultural fields. It is being fabricated by local blacksmiths and there is no scientific design for the pump. For low head high discharge conditions Petti and Para is very effective, but less efficient because of faulty construction. The broad objective of the project was to develop an axial flow pump with improved efficiency which could be economically used for dewatering and for lift irrigation purposes under low head conditions. In this investigation, a good amount of attention was given to the fluid dynamics inside the axial flow pump and theoretically studied the combined affect of various parameters involved in the design of an axial flow pump. Then the parameters were compared with the approximate values given by the various researchers in the field. The requirement of the pump to be designed, at field conditions, were studied thoroughly and an one dimensional design was done. After designing and fixing the dimensions, the pump was fabricated in the Kerala Agricultural University Research Workshop at Mannuthy. Because of the lack of facilities in the Research Workshop, it was tested in the hydraulics laboratory at the Government Engineering College, Trichur. The power unit used was a 15 HP electric motor. The accessories used to measure discharge and head were a rectangular notch with Hookgauge and water manometer respectively. Testing was done with two levels of water above the impeller, one 20 cm above the impeller and the other 10 cm above the impeller. For the above two conditions, at designed head (1.5m) the maximum efficiencies obtained were 33 per cent and 29.5 per cent at discharge 121 lit/sec. and 114 lit/sec. respectively. The maximum working capacity was 165.19 lit/sec. against a head of 1 m with an efficiency of 31.95 per cent (20 cm above the impeller) In the three bladed pump, the blades were fixed to the hub by welding it to the suitably shaped (curved) M.S flats and then bolting the curved M.S. flats to the hub. The blades were twisted from 160 to 240 in a uniform variation by simple blacksmithy. The efficiency of the pump can be increased by using perfectly curved blades, which reduces eddies and skin friction. Comparing with the existing Petti and Para made by local blacksmiths, it is found that the pump is cheap as well as efficient.ThesisItem Open Access Mechanical control of the floating type aquatic weed salvinia wolesta (African payal)(Department of Agricultural Engineering, College of Horticulture, Vellanikkara, 1981) Sankaranarayanan, M R; KAU; Jose, SamuelSalvlnia molesta, locally known as ’African Payal‘ is a noxious floating type aquatic weed of common occurance, particularly in the State of Kerala in India* The infestation is the heaviest in the Kuttanadu region and in the Kole lands of Trichur District of the State, where alone more than 50,000 hectares of inland water surface is under the grip of this weed. In the present project, the possibilities of mechanical control of the Salvinia weed were investigated* The study concentrated on the development and evaluation of a prototype Salvinia harvesting Machine which utilised a novel design concept of fluidising the mass by means of a centrifugal* ejector pump combination* The machine consisted of two 5 H.P portable pumpsets as the prime mover and an ejector system mounted on a floating platform. The machine pump out the weed-water mixture into a floating filtering unit at zero lift from which the water was drained by gravity, the material was automatically loaded into a country boat. The results of tests conducted indicated that the 10 H.Pmachine was capable of pumping the Salvinia weed at an average rate of 16 T/hr at zero lift conditions. The proportion of the weed pumped was of the order of 15 % by weight of the secondary flow when pump¬ing water alone. The special features of this equipment were that it could utilise conventional Irrigation punpsets as the prime mover and that it did not allow the weed materials to be drawn into and clog the primary pump. The machine was also capable of being operated as a self propelled unit. In this project, certain accessory units such as a gather¬ing arm, a floating fence and an automatic filtering unit were also successfully developed and evaluated* In addition to load¬ing the material into a country boat, a disposal technique of pumping the weed materials into a field fermentation pond, which avoided any immediate transportation costs for the harvested material, was also investigated. It was found that the bulk density of Salvinia was of the order of 400 kg/n3. It was also found that the spread density value of the weed, depending on the stage of growth and degree of packing, could vary from 8 T/ha to 32 T/ha. A representative value for the spread density, under the still water condition at Kuttanadu, was found to toe of the order of 16 T/ht. This meant that the prototype Salvinia Harvesting Machine would be capable of clearing the weed from a hectare in 10 working hours* The estimated cost of such an operation amounted to Rs.280/- per hectare which compared favourably with the reported costs of Rs.900/- to Rs.2700/- per hectare for manual collection and disposal of the weed. It is considered that the present work is a signi¬ficant contribution to solving the problem of African Payal infestation in Kerala State.ThesisItem Open Access Performance and ergonomic evaluation of direct pady seeder and mechanical rice transplanter in wet lands(Department of Farm Power Machinery and Energy, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2013) Rathod Sachin, Ravsu; KAU; Sureshkumar, P KAn experiment was conducted to evaluate the performance of the ‘Aiswarya’ 8 row direct seeder and ‘Mahindra PF455S’ 4 row walk behind mechanical transplanter with ‘Jyothi’ rice variety in wet lands from the ergonomic point of view. It conducted with selected male and female subjects in the age group of 25–35 years. The performance of these machines was compared with manual transplanting. The results show that the seed rate for direct seeder was very low with 37 kg ha-1 as compared to the mechanical transplanter (55 kg ha-1) and manual transplanting (72 kg ha-1). EFC found for direct seeder and mechanical transplanter was 0.11 ha h-1and 0.12 ha h-1 respectively. The field efficiency was found to be 69% for direct seeder and 74% for mechanical transplanter. Fuel consumption of the mechanical transplanter was found 3.7 l ha-1. The grain yield and straw yield in mechanical transplanting method was higher 2652 kg ha-1 and 3482 kg ha-1 as compared to 2265 kg ha-1 and 2885 kg ha-1 in the case of direct seeding. But in the case of manual transplanting, the yields were 2025 kg ha-1 and 2508 kg ha-1 respectively. The mean value of WHR and OCR with direct seeder was 145.5 beats min-1 and 0.95 l min-1 for male and 148.9 beats min-1 and 0.98 l min-1 for female. But in case of mechanical transplanter, the mean value of WHR and OCR was 131.6 beats min-1 and 0.80 l min-1 for male and 134.1 beats min-1 and 0.83 l min-1 for female. There was complete recovery of HR after 8 min with direct seeder and 6 min with mechanical transplanter. In case of direct seeder ODR, OSR, OER, BPDS values were given by male 6.5, 0, 6.0, 40.8 and by female 7.5, 0, 7.5, 45.6. The corresponding values for mechanical transplanter were 3.0, 1.5, 3.5, 36 by male and 3.5, 1.5, 5.0, 36. As per the grading of energy cost of work, direct seeder categorized as “very heavy type” and mechanical transplanter as “heavy type”. The 8 row direct seeder is not suitable for female subjects. A 4 row Mahindra walk behind mechanical transplanter could be used successfully not only to improve the yield but also to provide operator comfort as compared to the 8 row direct seeder.ThesisItem Open Access Development and evaluation of modified atmosphere packed passion fruit(Passiflora edulis)(Department of Post harvest technology and agricultural processingKelappaji College of Agricultural Engineering and Technology, Tavanur, 2012) Madhana Supriya, R; KAU; Sudheer, K PPassion fruit is a tropical fruit which is extensively used in juice processing. The fruit is highly perishable and losses its quality immediately after the second day of harvest. The postharvest loss in quality and commercial value is due to the intense respiratory activity and significant moisture loss. Hence a study was undertaken to develop a wax applicator to extend the shelf life of passion fruit by adopting the postharvest technologies. A simple and efficient wax applicator with a capacity of 250 kg.hr-1 was developed based on the physical properties of the fruits. Various samples of the passion fruits were treated with bee wax and commercial wax packed in LDPE bags of 200 and 400 gauge. The effect on the shelf life extension of fruits was investigated individually and in combination of wax and LDPE bags. In the case of LDPE bags, different levels of perforations such as 0%, 0.5%, 1% and 2% were used. The samples were kept in ambient condition viz., 32 - 35°C and 70 - 80% RH and at cold conditions as 7ºC and 90% RH. The physicochemical characteristics of samples were tested periodically at an interval of 5 and 7 days, under ambient and cold storage conditions, respectively. The results obtained were subjected to statistical analysis. From the results it was revealed that the samples kept in non-perforated polythene covers were found to be better than those kept in perforated bags and in normal atmosphere. A maximum shelf life of 40 days was obtained for passion fruits at 7oC coated with commercial wax emulsion. Thus, commercial wax coating in combination with LDPE bags acted as a barrier against moisture loss and respiration rate of fruits. However, the fruits kept as control had lost consumer acceptability after the tenth day of study at cold condition and within two days at ambient storage conditions.ThesisItem Open Access Optimum thresher parameters for high moist paddy(Department of Farm Power Machinery and Energy, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1993) Hamza, Mollakadavath; KAU; Sivaswami, MThe study undertaken by the newly development 1 hp paddy thresher to optimise its parameters for high moist paddy revealed that the peripheral velocity from 10.80 to 21.72 m/s on the rasp – bar, spike tooth, double directional spiral cylinders didn’t influence much on the threshing efficiency. When the moisture content was increased to 35 per cent, the threshing efficiency was brought down from 98.4 to 92 per cent for rasp – bar cylinder and was increased from 88 per cent to 94 per cent in the case of double directional spiral cylinder. The maximum threshing efficiency of 99 percent was achieved for spike tooth cylinder at 19.2 per cent moisture level. The maximum threshing efficiency of 94% and the maximum output of 340 kg/h were achieved with the double directional spiral cylinder when the moisture content was 35% per cent. The proto – type thresher was found to reduce the cost of threshing to 81 per cent and reduction in labour to 85.16 per cent compared to the manual threshing.
