MAHUWA NUT CRACKER AND OIL EXTRACTOR                         

May 2016

 

Problem Statement

Mohuwa is termed as the ‘tree of life’ for tribals In India. A mahuwa trees lasts for more than 100 yrs. 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 efficient and cost effective mahuwa seed cracking device.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Field visit

The team visited Meghraj, Sarangpur and Munshiwada in Gujarat to understand the problem of nut cracking. The objective is to find the most efficient idea and create a prototype which will suit the public in general across the country.

 

 

 

 

 

 

 

 

Insert video link

https://www.youtube.com/watch?v=l629ABZ2HDo

 

Observations from field visit:

  • An average tree produces 15-20 kgs of fruits throughout the season.

  • All the fruits are handpicked which causes shoulder and back problems. https://www.youtube.com/watch?v=aK9KsAGcLf8

  • 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 20kgs.

  •  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.

 

 

 

 

 

 

 

 

 

Mind Mapping

  • 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.

 

⦁ Safety measures

 

We have to ensure that there is no injury involved while operating the machine. The traditional method involves the risk of finger injury.

 

⦁ Cost Factor

 

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.

 

⦁ By-products

 

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.

 

⦁ Multiple applications

 

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.

 

⦁ User-friendliness

 

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. 

 

 

Decision Tree

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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 EXTRACTI 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

     

       Experiments​

  • 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 designconcept that           we derived from our observation

 

 

 

Modified sketch

 

 

 

 

Discussion with Sachin Panchal

  • A manual alternative has come up after the discussion with Mr. Panchal

  • A 3 plate device (25cm*25cm) 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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Prototyping

 

Prototype 1

 

 

 

 

 

 

 

 

 

 

 

Prototype 2

 

 

 

 

 

 

 

Prototype 3

 

 

 

 

 

 

 

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

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