CHARCOAL STOVE 78

            CHARCOAL STOVE
             

    DESCRIPTION: This fuel-saving stove is cheap as well as durable, apart 
    from being simple in design and convenient in use.
    CONSTRUCTION: This stove consists of a clay cylinder with a narrow waist 
    and a 50 cm square side opening at the base. It rests on a clay pan and a 
    removable convex clay grate is positioned inside the clay cylinder, 12 cm 
    below the top. About 300-500 of charcoal is placed within the upper 
    section of the stove and lighted. The ignition time is 15-20 minutes with 
    hardwood charcoal. There is no provision for heat regulation and no method 
    of extinguishing before the full charge has burnt out.
    The stove is made from clay, normally used in the manufacture of 
    earthenware cooking utensils and roofing tiles, modified slightly by the 
    addition of fine sand. Rural pottery centres can manufacture the stove by 
    using a pottery wheel. Moulds are not vital, they certainly improve 
    dimensional accuracy.

    WORKING: The stove consumes charcoal at the rate of 250 gms per hour with 
    a heating efficiency of 30%. A full meal for five adults is cooked in 
    approximately two hours with a charcoal consumption of 490 gms. Three 1 cm 
    thick ridges, equidistant from each other, traverse from the upper rim to 
    the inside of the stove till a depth of 6 cm. Small vessels fit snugly 
    inside the stove and larger vessels simply rest on the rim, but in all 
    cases, the ridges provide the space required for the escape of exhaust 
    gases.

    The grate, (concave-shaped to raise the charcoal bed towards the vessel) 
    has holes in 20% of the grate area, totaling 31 cm. square. The limited 
    air supply through the grate controls the rate of burning which is 
    approximately 250 gms per hour.

    SOURCE:
    Dhammika De Silva, Division of Wood and Cellulose Technology, Ceylon 
    Institute of Scientific and Industrial Research, P.O. Box 787, Colombo 7, 
    Sri Lanka  78