SK14 Modifications by AMSI

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The original EG-SOLAR SK14 solar cooker which had been copied and slightly modified according to the local requirements and manufacture possibilities to become the AMSI cooker.

 

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The modified AMSI-Solar-Cooker. The modifications are:

• Instead of galvanised flat metal bars, simple and cheap reinforcement bars which are locally available are used. All parts are welded together and not screwed which is cheaper, more durable and form-stable. The cooker can be used on uneven ground as well.
• The parabolic cage for the mirror is assembled and welded on a wooden mould to guarantee for shape precision even with low precision parts.
• The mirror-part can be easyly disconnected from the stand to allow the storage of the cooker in rooms with small doors.
• The pot holder is one part, firmly connected to the mirror. No parts may fall into the mirror and scratch the reflecting surface during transport and operation. The shape of the potholdes has been changed to allow the traditional cooking equipment to be used (The Jabena-jar and the Injerra-plate).
• The mirror panels are fixes with hard aluminium wire to the cage. This makes the fixation of the prefabricated mirror-panels on the usually inaccurate supporting circles easy and durable.

All modifications where made to adopt the SK14 concept to the local constraints of available material, inaccurate production and very rough handling which had to be faced.

Further modifications I want to make are

1. Avoiding the parabolic cage completely by connecting the mirror plates firmly with false (blind?) aluminium rivets. The shape of the mirror sheets has to be optimized for that purpose and the connection holes of overlapping mirror sheets have to be drilled very accurately, but than the right shape is simple and absolutely guarantied. I think of mirror sheets having interchanging trapezodial and triangular shape and arranged in rings.
2. Leaving a hole in the center of the mirror and slightly enlarging the mirror size. In the center of the mirror there is alway shadow made by the pot so removing the mirror there has no negative effect on the cooking energy provided. The hole at the same time replaces the solar gage to adjust the cooker. The cooker will be best adjusted if the shadow of the pot is in the center of the shadow of the mirror-ring on the ground, - very easy!
3. Because the mirror without cage is no longer so heavy the largest ring holding the mirror may be fixed directly to the pot-holder bar. The shape of the parabola has to be changed than so that the focus is in the plane of the largest ring. This again simplifies the construction and reduces weight and material. No pieces of sheet metal are needed any longer, so no drill mashine and sheet metal cutter is needed if the mirror sheets are pre-fabricated.