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1984 - 19874
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Subject: Agricultural Engineering × Author: KAU × End date: 1987 × Start date: 1984 × Thesis Type: M.Sc ×
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    ThesisItemOpen 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.
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    ThesisItemOpen Access
    Development of cocoa drier
    (Department of Agricultural Engineering, College of Horticulture, Vellanikkara, 1985) Abdassalam, M; KAU; John Thomas, K
    An investigation for the development of an electrically heated, multistage, agitation type cocoa drier, suitable for the Kerala conditions for drying of cocoa beans without impairing the quality, was conducted in the Agricultural Engineering Department of the College of Horticulture under the Kerala Agricultural University. The mini box fermentation method developed in Kerala Agricultural University was selected for fermentation of the beans. The fermented cocoa beans were dried in the sun. The process of sun drying continued upto seven days. The pH of dried beans was 5.2, which was very close to the pH range, 5.3 to 5.5 for good quality beans as per international standards. Hence, the quality of the beans was considered satisfactory. A bulb heated drier developed earlier in K.A.U. was tested* The capacity of the drier tested was 30 kg of fermented beans. The bean could be dried to the desired moisture content in 38 hours. The moisture content of the dried beans was about eight per cent. From the result it was found that for drying one kg of fermented beans approximately 0.760 K.W.H. of electrical energy was required. pH of the dried beans was 5.00. The bulb heated drier was modified and fitted with a 500 watts electric coil heater was also tested. Beans were dried to the desired moisture content in 34 hours. Moisture content of the dried beans was about eight per cent. The result showed that approximately 0.57 K.W.H. of electrical energy was required for drying one kg of fermented beans. The quality of the dried bean was satisfactory because pH of the dried beans was 5.0.The cost of drying per kg of fermented beans was Re.0.47. A modified C.P.C.R.I. model drier of capacity 60 kg of fermented beans was fabricated, tested and economics worked out. For attaining the required moisture content of about eight per cent, the time taken was 64 hours. The result revealed that approximately 0.533 K.W.H. of electrical energy and an amount of Re. 0.36, was required for drying one kg of fermented beans. pH of the dried bean was 5.1 and hence quality of the dried bean was also satisfactory. The modified C.P.C.R.I. model drier fitted with an half h.p. electric motor and a blower was also tested.Beans were dried to the desired moisture content in 42 hours. The result showed that for drying one kg of fermented beans approximately 0.610 K.W.H. of electrical energy was required. Cost of drying per kg of fermented bean was Re. 0.56, Quality of the dried bean was satisfactory since pH was 5.2. An agitation type electrically heated multistage drier of 90 kg capacity was designed, fabricated, tested and its economics was worked out. Tests were carried out with two quantities of cocoa (i.e. 90 kg, and 60 kg), 3 3 different quantity of air (i.e. 0.4 m /second, 0.2 m / second) and varying temperatures (i.e. 56°C, 47°C and 42°C). Air temperature and humidity at various sections of the drier were noted. Also the weight loss of the bean at every hour of drying was noted by using an infrared moisture meter, and the final pH of the dried bean by using a pH meter. From the experiment, using various quantities of beans, with different temperature and air flow, it was found that for drying 90 kg of cocoa beans a temperature of 47°C and air flow rate of 0,4 m3/sec was optimum, for this type of drier. The energy consumed/kg of bean was appromimately 0.69 K.W.H. The pH of the dried beans was found to be 5.3 and hence the quality of the dried bean was satisfactory. Cost of drying per kg of fermented bean was Re. 0.45. One of the objectives of this project was to evolve suitable design of an equipment for drying large quantities of cocoa beans. With this in view an agitation type multistage drier of 2000 kg capacity of fermented beans was designed. Prom the cost analysis it was seen that the cost of drying one kg of bean was only Re. 0.22. The cost of the drier was about Rs.23,000/-. The advantage of agitation type multistage drier are as follows. As the beans were moving in the drier better uniformity in drying was achieved and they were not exposed to high temperature continuously which helped in maintaining the quality of the beans. The drying time was reduced considerably. Energy consumption was less and cost of drying was only 50 per cent compared to other driers. Due to stage by stage drying the loss of heat is reduced and hence the thermal efficiency is high.
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    ThesisItemOpen Access
    Relative efficiency evaluation of drip and basin methods of irrigation in banana
    (Department of Agricultural Engineering, College of Horticulture,Vellanikara, 1985) Koshy, Vargees; KAU; Varkey, V K
    Well planned and efficiently utilised irrigation systems help to keep the food production in pace with the increasing population. Hence it is essential to design and adopt an efficient low cost economic irrigation system tailored to fit the local potential and needs. Out of the efficient methods of irrigation, drip method is the most promising. Drip irrigation is comparatively new to our country and needs popularisation. The relative efficiency and feasibility of a low cost drip irrigation system fabricated with the cheapest and locally available materials in relation to the conventional basin method of irrigation is tested in this experiment taking banana as the indicator crop. Plants were irrigated at the rate of 5, 10, 15 and 20 litres per day in both the methods of irrigation. Oil drums of 200 litres capacity were used as storage tanks for the drip irrigation system. 25 mm and 12 mm (dia) black low density polyethylene pipes were used for main and lateral lines respectively which were embedded at a depth of 20 cm below the ground surface. Micro-tubes of 2 mm diameter were used as drippers or emitters. The heart of this drip system was the distributor developed in K.A.U. which could deliver irrigation water at a slow rate of 1 to 2 litres per hour from each micro-tube. Physical characteristics of the soil and bio-metric observations of the plants were taken during the experiment. It was observed that there was no significant difference in the yield of plants under the drip and basin methods of irrigation. Similar results were obtained by Sivanappan et al. (1976) and Chennappa, (1977). The economy of the system was studied and it was found that, by adopting drip method of irrigation, there is a net saving of Rs. 4302 per year in one hectare. Weed growth was found to be less in the plots irrigated by drip method. Special skill is not required for the fabrication, installation, maintenance and operation of the K.A.U. drip irrigation system.
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    ThesisItemOpen Access
    Design and development of a high capacity Salvinia Harvester
    (Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1987) Hajilal, M S; KAU; John, Thomas K
    Salvlnla molesta locally known as 'African Payal* ia a noxious floating typo aquatic weed in many parts of the humid tropics. Kerala Agricultural university developed a mechanical device to harvest this menacing weed. An investigation on the performance of the prototype Salvinia Harvester was carried out under various conditions. Prototype ejector E1 with secondary flow straight and primary flow inclined at 900 ejectors E2 and E3 with primary flow straight end secondary flow inclined at 400 and 20° respectively and ejector E4 with secondary flow straight and primary flow inclined at 300 were tested along with circular mouth (M1), adjustable rectangular mouth (M2) and elliptical mouth (M3)• Experiments were also conducted to find out the optimum depth of mouth below the water level. The study revealed that clogging was a serious problem for the prototype Salvinia Harvester, where the weed was in the initial stages of third growth phase. Ejectors E1 and E2 showed clogging when tested with all the different feeding mouths. The E4-M2 and E4-M3 combinations yielded almost identical harvesting capacity of 11 t/hr at one metre static lift mad 12 t/hr at 40 cm static lift without any problem due to clogging. All these experiments conducted revealed that the ejectors E3 and E4 can be used under ell conditions of weed growth without clogging along with mouths M2 and M3. The machine is capable of removing weeds at the rate of 16 t/hr where the spread density value was around 16kq/m2 (160 t/ha) like Kuttanadu area. Hence the machine would be capable of Removing the weeds in one hectare in 10 hours. The estimated cost of operation amounted to Rs. 353/- per hectare which compared favourably with the reported costs of Rs.900/- to Rs.2700/- per hectare for manual collection and disposal.