Developing a manually operated stone crusher in Kaski, Nepal

Research data

Start of research: November 2007

End of research: May 2009

Research costs: 2.250 euro

This research has been conducted by Demen Hartman, student of Saxion Hogeschool in Enschede. He has developed several prototypes, for which he has found sponsors himself. We thank him for his fantastic contribution!

xxxxxxxxxxxxxxxxxxxx

The research

To make good concrete, it is of the utmost importance to add the correct size of aggregate to the concrete mix. In Nepal we usually see that the people use too large size of pebbles, simply because these are cheaper to buy. To improve this situation we will develop a small machine, which enables the people to crush the stones themselves. The design has to be simple, with minimal maintenance, and must operate without electricity, gas or petrol.

X

In Nepal the stones needed for all kinds of construction purposes are directly hauled from the river.

X

The required size of aggregate for concrete must not exceed 20 mm, but the pebbles from the river are usually bigger. Smaller sizes can be ordered with the stone suppliers, but for most people these crushed stones are too expensive.

X

To save money the people buy the cheaper, but too big pebbles. This results in the concrete mix being too coarse.

X

The structure of the cast concrete is too open, and there is insufficient concrete coverage on the reinforcement steel.

X

Water can penetrate the concrete easily, which causes rusting and expansion of the steel bars, and eventually cracking of the concrete beams.

X

Breaking the stones by hand is too labour-intensive; therefore we will develop our small-scale stone crusher.

X

Demen has made a first prototype in Holland, which easily breaks the stones. But he also discovered some difficulties with the transmission by spinning the wheel.

X

So he made new drawings and improved the mechanism of the machine. In Nepal a second prototype will be made.

X

Presentation drawings of the new concept of the crusher.

X

The first challenge in Nepal was to find a reliable steel production company, who has the appropriate machines to work the steel. And with personnel that knows about materials and understands mechanics.

X

We found a small workshop named Pokhara Engineering. The owner speaks good English and understands the drawings. Also they have the necessary tools and machines, such as a lathe and a milling machine.

 

X

The first parts are finished: the side panels of the stone crusher.

 

X

After some weeks all parts have been completed ...

 

X

... and the assembling of the machine can start!

 

X

The machine directly attracts lots of attention from the neighbourhood.

 

X

After the first tests we were not yet satisfied with the shape of the stones, so we have to make some more improvements.

 

X

Which meant back to the workshop, until we have made a machine that is good enough to be tested in one of the villages where we work.

 

X

The ride to Mugribesi is one to remember... We started with a flat tyre; by the way the picture on the right is the new tyre!

 

X

After that we bumped into a river with a water level that was slightly higher than we hoped for...

 

X

We got stuck in the middle of the river, and the people of Mugribesi helped us pushing the truck to the shore, which took more than two hours.

 

X

Finally the crusher has arrived in the village. Currently we are translating the test results in the Netherlands into a final type of the stone crusher.