| Boiling Point No. 01 - January 1982 |
SAWDUST RICE HUSK COOKER
J.A. Hazbun, WHO Solomon Is.
In the Solomon Islands, both rice husks and sawdust from the mills are burned as waste. This is not only wasteful, but causes a nuisance to neighbouring communities. The WHO Environmental Health Workshop has tried to develop a stove to make use of these fuels.
The stove is based on an oil drum with the top removed and a hole 5cm diameter cut in the bottom. A length of pipe is inserted into the hole horizontally, and a grill is placed on the top to support the cooking pots. A second pipe is inserted during filling of the stove with either rice husks or sawdust.
Initial trials showed that two litres of water could be boiled in 15 minutes. A cooker loaded with 20 litres of fuel will burn for 5 hours with virtually no smoke. This type of cooker has not been extensively tested for efficiency. It is intended to use these waste fuels instead of kerosene and thus save foreign exchange for the Solomon Islanders.
West Nepal Seminar
Ralph Bland ? a volunteer working in Pokhara, West Nepal attended a seminar for workers at village technician level on stoves. Several stoves were built and tested. Points raised by the seminar are as follows:
The stoves used less fuel than open fires and removed smoke from the kitchen. Less heat was lost into the room.
In the mountains, the reduction in space heating of the stoves was a disadvantage. Open fires would better suit cold climates and high altitudes. The smoke from the stove was not available for drying clothes and smoking meat and fish. The stoves required metal grates and dampers which were hard to obtain. The stoves were more complex to use than an open fire.
Most Appropriate Situation for Stoves
In view of the advantages and disadvantages, it was felt that stoves would prove most useful in hotels and restaurants where cooking and not space heating was required. The stoves were also better suited to warmer climates for the same reason.
Christopher O'Brien writes of his work in the Gambia:
"I've been introducing principally two types of stoves, both made from a "Lorena" type mix of clay and sand (usually a 1:4 ratio). The first type is for two pots since most Gambian meals are cooked with two pots; one for the rice or millet, and one for the sauce. The stove has a chimney made from a sheet of corrugated steel roofing. A baffle is built up across the flue under the second pot. I have built the stoves without dampers for the sake of simplicity, but the wood savings remain impressive. Women report saving 1/3 to 1/2 of the wood normally used with an open fire. The second type of stove is a simple one-pot chimneyless design developed recently in Senegal. The stove vaguely resembles a volcano, with the pot sitting in the "crater", and smoke escaping around the side of the pot. Women also report significant wood savings with these stoves and seem particularly impressed with the improved cooking speed.
I have tried introducing the stoves in a variety of situations. Most have been built in private kitchens, others in more public and visible locations -such as a training centre and a restaurant. Although most of the stoves built are in regular use, I've bee disappointed that they have not proliferated more dramatically; only a handful of stoves have been built independently. I'm hoping to improve the durability of the stoves by imbedding short lengths of mild steel rod across the cooking holes as supports for the pots, thus reducing the pressure and wear on the sides of the holes."
One Hole Louga Stove
Hanno Pilartz writes of his work with the Centre de Reintegration des Handicapes in Rwanda. The one-hole louga mud stove seems to fit their needs best. River clay and sand are readily available and the thick mud walls and massive bridge over the firebox are easy to construct. It is common to cook meals in a single pot beans are the chief food, requiring over two hours to cook.
He is working with three potters and two masons who generally try to build stoves they have designed themselves. These people have other jobs and are building stoves part-time in their own neighbourhoods. This encourages local interest in new stoves.
In the canteen at the centre the cooks wish to use waste burning stoves in place of butagas. They have a ready supply of free sawdust and coffee hurts which they can utilize.
Tim Wood, VITA Representative in Upper Volta writes of his - problems when employing local potters.
"I had a potter make a dozen sets of inserts and they were beautifully done, but lack of proper fuel for his kiln forced him to burn them in an open pit, and in the process every one was destroyed.
The same potter spent considerable time in late spring adapting the double-skinned stove to local cooking needs, and came up with some very good-looking models. The modifications were mostly around the rim, flaring it out more and providing three evenly spaced pot supports around the inside. The dimensions were such that the stove would accept almost any size of round-bottomed aluminium pot. Malheureusement, most of these stoves were also destroyed upon firing, although the earlier prototypes have survived. The potter is a skilled craftsman who has spent most of the past two years making a clever chicken waterer that is sold throughout West Africa. He plans to abandon that completely after the harvest this year and concentrate on stoves, where he sees a lucrative market. His firing technique is fairly advanced over the traditional method as long as he has the proper fuel (millet stalks ) .
WOOD CONSERVING COOKSTOVES - A Design Guide.
This manual has been prepared by VITA in association with the Intermediate Technology Development Group with the aim of providing information and encouragement for those working in the field.
Send your order together with a cheque/bank draft for £ 4.50 per copy ( despatch by Air Speeded Post where available, otherwise surface mail ) to Intermediate Technology Publications Ltd, 9 King Street, London W. C. 2, U. K.