Effect of thermal shock on the grates of improved charcoal cook-stoves made from different materials

摘要

From the current literature on cook stoves, it remains unclear on which is the best temper and the alternativesoils that can be used in the production of charcoal cook-stoves that are resistant to thermal shock. To this end,a study was conducted to determine which soil type and mixing ratio that can produce the highest thermalshock resistance when used as grates. The grates made of clay, red and anthill soils each mixed with shale rockin ratios of 1:0; 1:1; and 3:1 were compared. The grates were fired and then heated in a furnace set at 400 °Cfor 1 h and subjected to two cooling treatments; rapid cooling by quenching inwater and cooling at ambient temperatures,for seven subsequent cycles after being heated. The shock resistance for all the grates made from differentsoil types and different mix ratios was measured based on crack initiation and propagation according toASTM C1525-04 standards. The results showed that clay soil mixed with shale rock in the ratio of 3:1 had thehighest thermal shock resistance with no crack initiation throughout the heating and cooling cycles, followedby anthill soil mixed with shale rock in the ratio of 1:1. Therefore, charcoal stove users and manufacturers canexpect a better quality productwith high durability if shale rock is used to temper the cook-stoves in comparisonto burnt bricks that are currently commonly used in Uganda. The method used in this work can be applied inother regions to come up with more material ratios that are resistant to thermal shock.