Slow speed grinding machine.

1) The main objective of grinding machine is to grind grains like wheat, millet, pearl millet,wet or dry pithi, spices, pulses with slow speed to avoid the losses of nutritional values & flavour due to heat generated in conventional grinding process.

2) Grinding of grains & pulses is a day time operation & hence can be switched to PV cells without battery support. This will cut-down carbon footprints.

3) To develop Automatic feeding mechanism

Literature survey of previous documents of slow speed grinding machine :-

Automatic feeding mechanism for slow grain grinding machine:-

a) RPM for grinding M/C by measuring the revolution of sprocket chain mechanism ( in transmission practically).

  1. For 1.5 min & 20 rev, Speed = 20/1.5= 13.33 RPM.
  2. For 3.26 min & 43 rev, Speed= 43/3.26=13 RPM.
  3. For 6.02 min & 75 rev, Speed = 75/6.02=13 RPM.

Hence, average speed (in RPM) = 12 RPM.

b) Feed rate calculations:- ( Assumptions made on the basis of Ashram’s requirement for making Idly for 60 people)

  • I had taken a trial to grind 20 gm rice grins.( On grinding m/c in project )
  • To grind 20 gm rice grains, 1 min. 39 sec i.e. 99 sec is require.
  • Therefore, required feed = 99 sec/ 20 gm = 4.95 sec/gm ~ 5 sec/gm
  • Hence, Feed require in 1 min = 60/5 i.e. 12 gm/min.

c) Total feed rate require for grinding m/c. is,

(12 gm/min)/(12 rev/min)=1 gm/rev.

  1. Rice require for 60 people in Ashram for making Idly :-

60 people in Ashram requires 12 glass of rice for 1 day. (Fig. told by Maushi)

Where, 1 glass had 308 gm of rice.

Hence, 12 glass = 308*12=3696 gm rice.

Hence, 60 people requires 3696 gm of rice for 1 day in Ashram.( Let us assume that 10 people didn’t eat Idly)


  • Rice requirement for 1 person = ?


=61.6 gm/day/person for making Idly.

  • Calculations for the requirement of rice /day for 1,324,171,354 people allover the India:-

Population of India in 2018 = 1,324,171,354 bn

Therefore, per day Rice requirement = 61.1*1,324,171,354.

=81,568,955,406.4 gm/day for 1,324,171,354 peoples in India.

  • Calculations for the requirement of wheat/day/person in Ashram :-

70 people in Ashram requires 50 kg (50000 g) of wheat for 4 days (Fig. told by Maushi) :-

= 50000/70

= 714 gm

Wheat requirement for 4 day = 714 gm

therefore, for 1 day wheat requirement = 178.5 gm.

So, 1 person requires 178.5 gm of wheat for 1 day.


  • Calculations for the requirement of wheat/day for 1,324,171,354 people allover the India:-

1,324,171,354 * 178 = 235,702,501,012 gm per day


Requirement of wheat for 365 day = ?


=86,031,412,869,380 gm for 1,324,171,354 people in India.

Requirement of 1,324,171,354 people in India for wheat & rice per day / person is 178 gm & 61.6 gm respectively .

So, my grinding m/c needs to grind around 119.8 gm of grains per day.

d) Had Install 12 volt SMPS on m/c to covert 230 volt AC to 12 volt DC supply.

e) Had replacement of Ball Bearing.

f) Taken the trails of 2 cm long sticks on grinding m/c to know the capacity of grinding m/c.( sticks are given by Colonel Naik )

g) Purchasing of a New Grinding M/C is done.

h) Total Electricity consumption of India during grain grinding process.

i) Comparatively efficient use of solar energy.

New problem is arrived :-

  • Driving & driven sprockets of transmission system of grinder are miss aligned.
  • Which creates vibrations & ultimately other parts of machine get disturbed .
  • So, my task will be to adjust the alignment between driver & driven sprockets.

For that I have design a support plate for driven sprocket with 2.5 cm thickness & have cut it on Plasma Cutter.

  • I practiced welding , grinding , drilling.

  • To adjust the alignment of driver & driven sprocket, I have mount the driven sprocket with support plate 2.5 cm away from motor mounting.
  • Which made inline operation of transmission system.

  • Machine was not working due to loss motor connections :-
  • So, I had provide it with some fix mounting.

“After having a discussion with Kulkarni sir, Arun Dixit sir & Amol sir it was decided to made an Automized flour mill for using the slow grinding technique with reduction in human efforts”.

Mill stone purchasing for Automized flour Mill :-

  1. Different types of mill stones patterns available:-

Mill Stones Purchasing :-

Different rough surface of millstone :-

3) Different parameters to be find while selection of mechanism for Automized of Flour Mill :-

a) Weight of rotary mill stone = 13.938 kg ~ 14 kg.

b) Diameter of millstones = 35 cm.

c) Speed in RPM (During hand operation) = 68 rpm.

d) Frictional resistance/Frictional load = 41.202 N.

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e) Power require:-

4) Proposed mechanisms after having discussion with Amol sir :-

a) Block diagram of Automized flour mill :-

b) Axial drive & drive wheel on drive surface mechanism :-

c) Peripheral drive system :-

MSDCL’S data available on internet:-

  • Data of motor & energy bill of Pabal’s flour mill:-

I have visited Pabal’s Flour mill for collecting data :-


For 31 days electricity consumption is 354 units which charges Rs. 2999.

  • Carbon emission in atmosphere :-

The study claimed the average efficiency of the plants, it assessed, was 32.8 per cent, one of the lowest among major coal -based power producing countries. It claimed that average CO2 emission was 1.08 kg per kWh.

Capacity of available hopper :-