[Stoves] Pema Pot Skirt

[Jigme Rangdrol]

The Pema Pot Skirt

There seems to be actual agreement that pot skirts make combustion 
stoves better.
It is clear however that the bulk of deployed stoves do not have pot skirts.
Therefore an inexpensive pot skirt that could be made in the third and 
fourth world for those deployed stoves would have some usefulness.

Such a skirt would have two defining characteristics.
The ability to fit existing stoves and the ability to be manufactured 
from inexpensive materials without the use of power tooling.

Our experience with the third and fourth world cooking made it clear 
that a single design would not be sufficient.
As it would be impractical to have a set of pot skirts a single 
adjustable skirt design would be ideal.

To this end  the Pema Pot Skirt - [P2S for those in need] is presented 
for your considerations.

The basic structure consists of a metal ring "base" that sits flat 
around the stove exit port and a series of metal "petals" that hinge off 
the base and nest together to form an adjustable skirt.
The petals can be made of "waste" metals, cans and tins etc with hand 
shears or knives and a punch or nail. Ideally they would be formed by a 
simple press punch.
There are two types of attachments between the petals and base, tube 
hinge and tine hinge. Tines for those who can punch the petals during 
manufacture and tube for those who cant.
The base base can be formed from the top of any large can that has a 
pressed or rolled seam joining the top to the side. Ideal  units of 
course would be made of heavy stock like the base of the
New Dawn Engineering Open Source Paraffin Stove.
 
The upper limit of the pot size is controlled by the balance point of 
the petals. This limits the inexpensive units to large flat surface stoves.
As the unit cost rises however the design can incorporate more metal to 
overcome the balance point and thus fit to stoves of smaller surface area.
So three or four sizes could accommodate most stoves and pots in these 
conditions.
The lower limit of the pot size is controlled by the length of the 
petals. This may actually be the best part of the design as it can 
increase the surface area the heat is concentrated in.

The test was made from a vegetable steamer that cost between $US 1.08 
and 1.11 new. As the vast bulk of that price is taxation, transportation 
and packaging it seems reasonable that these units could be mass 
produced for less than $US 0.25 to 0.40. In some third and fourth world 
communities the cost could well be far less.