Design and Fabrication of Ragi Ball Machine
Design and Fabrication of Ragi Ball Machine – Mechanical Project
Finger millet, popularly known as ragi flour is an annual herbaceous plant widely grown as a cereal crop in the arid and semiarid areas in Africa and Asia. Ragi Mudde or Ragi Sangati is a wholesome meal in the state of Karnataka and the Rayalaseema region in Andhra Pradesh. In this project, a Ragi Mudde Machine is proposed, where the finger millet and the water are boiled inside a stainless steel vessel using a burner and then the dough is made by continuous stirring of the mixture by using stirrers and pusher plates. Thus obtained mixture is forced out automatically through a pipe via pusher plates and then formed into round shape using a bowl powered manually.
India is the leading producer of small millets namely, finger millet (ragi), kodo millet (kodo), foxtail millet (kangni) and little millet (kutki). Annual planting area under them is around 2.5 million hectares and nearly 1.5 million hectares is under finger millet comprising 40-50% of crops global area. Its annual production is maintained around 2.4 million tonnes. The protein content in ragi is more or less equal to that of wheat, rice and maize. Finger millet contains the lowest fat. It is relatively rich in iron and phosphorus. It has the highest calcium content among all the food grains. The most common primary processing of finger millet is to convert the grain in the form of flour which is achieved by pulverizing or milling. Some of machines for milling are conventional stone mills, burr mills, hammer mills, ball mills etc. on demand of the recipe the coarser flour is separated by sieving the whole meal. Finer flour is preferred for making chapathi (rotti), whereas coarser flour is suitable for mudde. Mudde is a typical preparation of Karnataka and very often prepared using social functions. Coarser flour helps in making lumps during mudde preparation and that of finer flour absorbs more water due to higher surface area and facilities flattering for chapathi making.
In recent years the consumption of finger millet along with other millets has been increased particularly in the urban sector due to awareness about the inherent nutritional and medicinal properties of millets. Millet is gluten free and safe to eat for those who experience gluten sensitivity.
PARTS OF RAGI BALL MACHINE
1. Stainless Steel Vessel
The vessel used here is made of stainless steel 316 of around 2mm thick. It is made by welding a sheet in cylindrical form with a round sheet welded to it at the bottom. It helps to store the mixture of ragi flour and water during the preparation. It also houses the stirrer blades and the pusher plates used for stirring the mixture inside it connected by shaft at the centre of the vessel.
2. Support Structure
The support structure is made of stainless steel square bars of 202 type. It helps the vessel rest on it to accompany the overall procedure. It also provides for accommodating motor, gear box along with batteries to run the machine.
3. Shaft with stirrers and pusher plates
The shaft and stirrer assembly is made of stainless steel 316 which rests on the vessel above a ball bearing. The four stirrers are provided at an angle of 45 degrees to the centre and the 2 pusher plates are provided at an angle of 180 degrees to each other. The stirrers and the pusher plates helps in stirring the mixture inside the vessel to required consistency and also helps in forcing out the dough out of the vessel.
4. Extrusion pipe
A Stainless steel pipe is being welded tangentially to the bottom surface of the vessel which is used to force the mixture of it once it is ready. The pipe will be closed with stainless steel cap with a rubber flap to avoid leakage of water and flour during the process using nut and bolt assembly.
5. Non-stick sol gel coating
Coating is provided on the inner surface of the vessel, stirrers, pusher plates and extrusion pipe to avoid the mixture getting sticked to it and also for smooth rotation during mixing process. Its composition is PTFE and its thickness is around 60 – 70 microns.
6. Motor with gear box
To run the shaft assembly for mixing, it is powered using a 0.5HP DC motor coupled with a gear box of 30:1 ratio to obtain a speed of 100 rpm which is run by a 24 volts battery.
Fasteners are used to mount the vessel on the outer structure and also for resting the motor on the support structure an assembly of steel rod is fastened to it.
8. Rotating bowl
A stainless steel bowl with an handle is being used to rotate the dough coming out from the extrusion pipe and form it into round shape.
A detachable burner is provided at the bottom of the vessel to heat the mixture to the required temperature powered by a gas cylinder.
This equipment will help in reducing the effort to make mudde in large quantities. Mass producers of mudde like in temples, hostels, restaurants can make good use of the machine. It also saves the time required to clean after cooking in it due to the non-stick coating. Thus, it helps to produce healthy ragi mudde which is very soft, tasty and completely
free from lumps.
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