Mahuda Seed Cracker
By: Rishabh Jain, Hard and Kuldip
The Mahua tree is a widely found tree in the central and northern part of India. Its flowers and fruits are used for various purposes. The flowers are used to produce alcohol and also used for there medicinal properties for getting relief from cough/cold and joint pain when used for massage. The seeds inside the fruit are used to extract oil which is mainly used for cooking purposes.
Characteristics of the tree
35-40 ft high
25-30 ft in span
Flowers harvested in the month of March
Seeds mature in the period of May-June
Flower is succulent in nature
Used to make alcohol
Browns when dried
Major issues, important concerns and potential opportunities related to the Mahua Tree
We visited the village of Rangpur near the city of Chhota Udepur in Gujarat, which is close to the MP-Gujrat Border. This place was chosen for its Mahua tree growth and access to the tribal communities. Chhota Udaipur is also home to oil mills where the residents of the nearby areas get the oil extracted. On the first day, we met Parsingh Rathwa, who is a small farmer and a teacher along with his wife Bhawna Rathwa, who is a homemaker and an aspiring advocate. Parsingh told us all the necessary background knowledge about the Mahua tree and its social dynamics. The next day we talked to an Oil Mill Worker, Karan Bhai and Bibli Ben Rathwa .
The trees in this area are treated as a community resource and the fruits are shared by all. Everyone picks up the flowers or fruits that are fallen on the ground. Since the ripe flowers/fruits fall to the ground anyways, no one usually picks them off the tree. After monsoon has arrived people quickly pick the remaining fruit off the trees as they turn useless after rain. The people in the area go around collecting the flowers all day during flower season as the more time they spend collecting, the more they will have. It is easier in fruit season since it suffices to go twice a day. Usually, the whole family(including children) is involved in the process of collection.
Then we learnt about the processes that the collected products undergo.
Flower to Alcohol
The Alcohol apart from being used as an intoxicant has a multitude of uses. It is used to treat cold, cough & joint pain in patients as young as infants both as a rubbing agent(massage) and as an oral medicine. One little-known use that was also told to us was its usage in treating paralysis after mixing the alcohol with pigeon’s blood.
1) Dry the flowers for 3-4 days in the open
2) Soak the flowers in a pot of water for about a week and keep away from direct sunlight and
3) Boil another pot of water and add to the first pot
4) Put the whole mix in the distilling setup
5) Distil the alcohol to a concentration of choice
An upside down pot is stuck to the mouth of an upright pot and sealed using clay. A pipe is added to a hole in the top pot and the vapour is condensed in another bottle. Seeds to Oil The oil is used for cooking and for massage for relief in joint pain. The oil is extracted from the innermost core of the seed which is obtained by cracking open the hard shell which itself is covered by a green fleshy coat.
Seeds to Oil
The oil is used for cooking. It is also used for massages, for relief in joint pain. The oil is extracted from the innermost core of the seed which is obtained by cracking open the hard shell which itself is covered by a green fleshy coat.
1)the fruits are stored in a cool and dry place until the further place. The green covering is left in sun to dry so that the covering is easy to remove with hand.
2)After the covering is removed, the next step is to take the seed out from the hard brown cover. A stone is used to force open the seed by hammering it on a specific place on the seed.
3)The seed is separated from the broken covering by hand. All the seeds are dried in the sun for 2-3 days.
4)the seeds are taken to an oil extraction machine in Chhota Udaipur. The cost of extraction of oil from 1 kg of seeds is 3 rupees.
After the field visit, we revisited the mind maps and also engaged in making process maps. This helped us deepen our understanding of the problem and the context. It also helped us to better identify key areas where work could be done effectively.
The problem of breaking the seed open before pressing it for oil is one that is chosen since making the process faster will make it possible for the people to free up a lot of time in the day. The current process takes around 20 minutes per kg of Mahua seeds.
“How might we reduce the time needed to crack open the Mahua seeds”
We looked for existing seed crackers used for groundnuts and other nuts. We also looked at methods used across industries for breaking things.
We idea-ted around the problem and decided on using a horizontal rotating drum with steel balls in it. This technique is currently used for crushing stones to a fine powder. We chose this technique because it is robust, cheap and easy to implement and replicate.
Details of design
Steel drum 10” diameter, 5 mm thickness
Handle made of 4 mm steel sheet
Pillow block ball bearing
Steel balls 30 mm*10, 50 mm*5 diameter
Rubber wheels with fix castor*2
The design went through two versions: v 1.0 Steel cylinder with the smooth surface was not able to take the balls up to a significant height for suitable impact. v 1.1 Added fins inside the cylinder to help take the balls to a greater height for a larger impact.
To make the drum a 5 mm steel sheet was bent into a cylinder of diameter 10” and depth 8”. Two 3 mm steel circles were also cut to make the front and back of the drum. One of the sheets was welded to the cylinder. The other was cut in two parts along a chord and a hinge was added there to make the door. On the fixed plate side, an axle was welded to help mount the handle and the bearing. The fins were made out of 3 mm steel sheet as well. Strips of metal were cut and welded to the inside of the drum. All welding was done using an arc welding machine. The whole mechanism was supported by and mounted on a scrap piece of wooden board. The supporting wheels were screwed to the board, After determining the correct height for the supporting pillow block bearing a small welded structure was made out of steel angles to raise it to the correct height. This structure was also screwed to the base plate.
The prototype is able to crush seeds now. The users reported excess noise, a great increase in performance on tilting the device, a need to improve the locking mechanism for the door, a need to make it easier to empty the drum once it is used.
Future plans for it include optimizing the design to reduce weight and increase efficiency. Another possibility that needs strong exploration is making the product with widely available objects like Milk Containers/Paint Cans, Bicycle Pedal arms etc. Material exploration in the current design is also a possible field of work. One wild but possible exploration is also the possibility of cold oil extraction as well.
MAHUA NUT CRACKER AND OIL EXTRACTOR
Mohua is termed as the ‘tree of life’ for tribal In India. A mahua tree lasts for more than 100 years. The fruits are handpicked which causes shoulder and back problems. The seeds are cracked by stones for ages. Kernel is extracted manually, which is time consuming.
The objective is to design an efficient and cost effective mahua seed cracking device.
The team visited Meghraj, Sarangpur and Munshiwada in Gujarat to understand the problem of nut cracking. The objective was to find the most efficient idea and create a prototype which will suit the public across the country.
Observations from field visit:
An average tree produces 15-20 kg of fruits throughout the season.
All the fruits are handpicked which causes shoulder and back problems.
Oil produced in the process is used by the family and no part is sold. The kernel is given to a local market proprietor for grinding.
The waste generated after extraction isn’t returned to the farmers, but kept by the grinding person.
The rate of grinding is Rs 40 for 20 kg.
The cultivators were eager for a solution which can help them out and is cost effective and efficient.
There is no need to steam the seeds before grinding which is traditionally used.
It takes 3-5 days to dry the kernel in direct sunlight.
It is used as an alternative for the edible oil.
The outer cover of the fruit is soft and can be removed by pressing through hand.
The outer pulp of the fruit is used in fertilizers.
These seeds can be preserved for more than a month after plucking.
There has been no other mechanism other than stone hammering of the seed.
There is a specific pressure point at the seed from where it breaks into two pieces with very minimal force.
The shell covering the kernel is very smooth, slippery, tough and brown in color.
After cracking the outer shell of kernel, it is hard to remove the shell from kernel (egg analogy).
Affordability: participants suggested that they can afford a machine in a range of Rs 2000 to Rs 3000.
After oil extraction, the residue of kernel is used in making kanjar cake, which is used to feed cattle.
The unripened seeds can be ripened by spraying water over it.
At no point of time water should be used on ripened seeds, as it destroys the fruit.
There can be multiple seeds in one fruit.
No new trees are being planted and the farmers depend on the existing ones.
Methods of cracking the nut of mahuwa fruit
The methods are soaking,freezing the thaw, grinding ,punching, peeling, hammering, srcubing, acidification, spiking, French press, shaking, heat breaking, rolling. The traditional nut cracking technique is stone hammering used by majority.
Mechanism of each method and its efficiency
The hammering method is currently the only method used to crack open the seed and then peeling the outer shell to get to the kernel.It requires aim and identifying the right pressure points on the seed.
Oil extraction methods
The method is combination of processes like drying the kernel, grinding, steaming, crushing, squeezing and extracting the oil. The drying stage itself requires 2-3 days of time.
We have to ensure that there is no injury involved while operating the machine. The traditional method involves the risk of finger injury.
The machine has to be affordable, such that the worker does not have any economic issues in buying the device. Also the repairing costs must be minimal.
They include the fruit, the seed and the outer shell. The fruit is used to prepare delicacies and the outer shell is a waste product. Kanjar is used as cattle-feed and manure.
The three main processes of collection, grinding and crushing can be combined into one. This would not only save time but also help in efficiency with better yield. Refining the extracted oil to filter out the impurities and increase its purity can also be added.
The machine must be user friendly for 20 and above age group. No sophistication should be involved in the machine parts. It should be compact and easily transportable. Material must be easily available and the easy to maintain.
Idea to Concept
The team came up with a bunch of ideas and designs for the prototype.
1. Peddled Hammering
2. Spinning Wheel
3. Integrated Extract Machine
4. Screw Press
Proof of Concept
Ripened food is very soft and the inner portion can be eaten
Seeds vary in size. Average dimension is 3.5*2.5*1.5 cm
Specific pressure point (indicated with red star) which needs minimum force to break open the brown shell
Removal of brown shell from kernel is very hard as it sticks to the kernel very tightly
The team tried perforating the seeds and then saw the effect on removal of the kernel. REMOVAL GETS MUCH EASIER
The team tried soaking of the seeds in water. INSIGNIFICANT EFFECT OF REMOVAL ON INTACT SEED, SIGNIFICANT EFFECT ON PERFORATED SEED
The team tried scrubbing against each other after making cuts on seeds. REMOVAL GETS EASIER
To be done: Heating the seeds, Boiling the seeds, Freezing the seeds, roasting the seed in sun light
Feedback on concept Discussion with Prof. Kodar Patel Earlier we came up with the seed on the nail-bed design with the approval of the professor, we moved forward to devise a mechanism based on the above design concept that we derived from our observation.
Feedback on Prototype
Size and mechanism optimization of prototype 1
Seed sorting in hopper in prototype 2
Dimension optimization of prototype 3 in order to perform efficient crushing
Automation of prototypes
Kernel and shell separation after cracking of seed
Oil extractor to be fine-tuned
Discussion with Sachin Panchal
A manual alternative has come up after the discussion with Mr. Panchal
A 3 plate device (25 cm*25 cm) which will include a nail-bed (with nail height of 4 mm), an iron net (which will allow not to stick the seed in the nails), and a heavy punch