36 



[July, 1908. 



TIMBERS. 



METHOD OP CHARCOAL BURNING 

 IN SALEM DIVISION. 



By T. S. Tirxtvenkatachari. 

 Range Officer, Salem, East. 



On my joining tlie Harm' range in 

 South Salem Division, I was called on to 

 nuike some charcoal. Accordingly, I 

 collected some coolies, who knew a rude 

 though intelligent form of charcoal burn- 

 ing. They made some charcoal which 

 was not very gocd. Their kiln was 

 rather loosely built and allowed the 

 smoke to pass through the top. This 

 charcoal fetched a price ot Rs. 10 to 

 Rs 12-8 per ton locally, being somewhat 

 inferior. Then I adopted the following 

 form of kiln which is nothing more than 

 the parabolloid kiln of Dehra Dun, but 

 this one gives better results and is not 

 so complicated in working and making. 



Description. — The billets are cut to a 

 length of 4 ft. Even while the fuel is 

 quite green, the kiln can be arranged 

 by using the biggest pieces for the 

 innermost ring leaving a vertical hol- 

 low ot 2 ft. in diameter in the mid- 

 dle- This hollow is connected with the 

 outer side of the kiln by a channel 

 which is made by temporarily placing 

 a long straight piece of wood, lead- 

 ing from the central hollow to the 

 outside. The kiln may be built on any 

 level ground and no digging or prepar- 

 ation of the site is necessary. Having 

 arranged the biggest pieces around the 

 firing centre, smaller pieces are arranged 

 vertically in concentric outer layers, and 

 even the smallest branches and twigs 

 are used in the outermost layer. All 

 through the interstices between the 

 larger billets are filled up by smaller 

 pieces in order that the stacking may be 

 as tight as possible. The diameter of 

 the kiln is from 8 to 12 ft. according to 

 the quantity of wood used. In»30vering 

 the kiln, a ring 9 in. thick of brushwood 

 and branches, like a well crib is sup- 

 ported at one foot from the ground by 

 props of short forked billets driven into 

 the ground. Making a smooth curve 

 with this outer ring, leaves and brush- 

 wood are thrown over. Then moist is 

 put on to thickness of 2 in. and pressed 

 down to make it ae airtight as possible. 

 The greater part of the weight of 

 the outer covering of leaves and 

 earth is supported by the short props 

 which hold up the crib-like ring. All 

 below this ring is uncovered, allowing 

 free access of air. Generally four to six 

 tons of wood are used for a kiln, but 

 ©yen up to ten tons can be vised at a 



time. Smaller kilns, however, are much 

 more easily managed than the bigger 

 ones of eight or ten tons. The kiln can 

 be built at any level place irrespective of 

 the distance from water, for six or seven 

 buckets will suffice for preparing the 

 earth for the covering, and this small 

 quantity can be brought from a distance 

 if necessary. 



Firing.— A torch is pas-ed through the 

 channel-like opening into the central 

 space which is filled with dry brush- 

 wood. This channel is left open for two 

 hours, after which it is closed up with 

 wood. 



Working of the Kiln. — As soon as the 

 kiln has taken fire it has to be watched 

 by two or three coolies until the whole 

 kiln is burnt. Short pieces of fuel are 

 kept ready to fill up hollows which occur 

 when the kiln settles on account of the 

 burning of the inner layers of wood. 

 Whenever such hollows occur they are 

 easily filled with pieces of fuel ; the 

 covering is repaired with leaves and 

 earth and made airtight once more. 

 There is no making of holes for air at 

 various heights as in the ordinary para- 

 bolloid kiln. The burning continues 

 from three to four days according to the 

 size of the kiln. Any outside air current 

 does not affect this kiln perceptibly, as it 

 does when holes are left for controlling 

 the burning. When the fire has reached 

 the outermost layer and the outer cover- 

 ing of leaves is burnt, the bottom one foot 

 opening is closed completely and the 

 kiln is allowed to cool down for a day, 

 after which the charcoal is taken out. 



Advantages of the Kiln. 



(1) Water is not required close at 

 hand. 



(2) Outer air currents do not affect the 

 burning. 



(3) The outturn in good charcoal is 

 from 25 to 30 percent, of the weight of 

 the wood ; the minimum is 25 per cent. 



(4) Green fuel may be used in this 

 kiln, and no time need be lost in drying 

 the wood. Dry wood is a disadvantage, 

 and green fuel is particularly advanta- 

 geous as it moderates the burning to an 

 immense degree. 



(5) Even the smallest branches are 

 used, and on opening the kiln it can be 

 seen that even leaves sometimes retain 

 their form after being carbonised, show- 

 ing that as little disturbance as possible 

 takes place and burning is moderated 

 exactly and automatically by the green 

 fuel. 



