VSBK – 10 was ignited with one shaft on 10^th. February, 2002 with subsequent second shaft firing on 16^th. February, 2002. Although construction was completed about a month earlier, firing was not started due to absence of ramp, side covering of the loading platform and the roof shed. Entrepreneur was convinced to lay the MS jalli covering and GI roofing shed before start of firing to ensure adequate safety measures for loading animals and workers at the loading platform and protection from natural calamities – unseasonal rains.

Due to non availability of VSBK Service Centre fire masters firing was initialized by firemen from VSBK-5, Mr. Narayan Das, wherein stabilization was reached by Service Centre fire masters. Green bricks moulding is being done in two sizes, regular and matrix. Green bricks contain internal fuel at 6% by weight and rice husk 2% by weight to avoid cracking in this season.

During this one and a half month of production entrepreneur has been unloading around 18 to 22 batches per 24 hours shift. Undoubtedly quality of fired bricks improves with lesser unloading rates. Total number of bricks produced is approximately between 4.5 to 5 lakhs, all of which has been sold at a rate of Rs. 1050 ex. site.

To maintain high unloading rate and fire in the central position entrepreneur has inadvertently increased the airflow in the shaft by introducing 20 – 25 mm gaps between bricks which also reduce the capacity of the number of bricks loaded. To maintain the above gap a judicious mixture of normal and matrix bricks are being loaded in the chulha and spreading layers. Coal consumption at present is 18 kg per batch spread equally between 3 layers. This works out to be approximately 6 tonnes per lakh which is less than half the amount previously consumed in his movable chimney and open clamps. Out of a total of 310 bricks loaded around 3 to 5% is broken due to faulty and quick unloading, uneven wooden and MS bars. All the above unloading materials has been procured from Mr. Narayan Das. Entrepreneur has been pointed out the reasons of high breakage and convinced to change the unloading equipments from the nest season according to DA specifications.

Due to high rate of unloading (22 batches) sometimes the periphery of the unloaded batch i.e. around 60 bricks (20%) is of Class II quality. However entrepreneur is not very much concerned about it, since he has the ability to sell Class II (in terms of colour) at the rate of Class I only.

n this pattern out of a capacity of 296 – 308, only 280 bricks per batch were loaded. Six batches from the bottom contain 40 kg fuel (coal) wherein in the next 6 batches fuel was reduced to 36 kg keeping the brick quantity same. Lesser number of bricks opened up the interstitial gap thereby increasing airflow. Increased air movement enabled faster travel of fire from the bottom thereby stabilizing the kiln in minimum time.

Presently entrepreneur is unloading 16 batches per 24 hours shift from the two shafts, containing 304 bricks per batch. Coal consumption presently is 6.5 to 7 tonnes per lakh. Rejection is only due to unloading breakage which is approximately ranging between 2 – 3 %. There is no colour distortion at the periphery and whole batch is uniform in colour. In the second shaft colour and quality of fired bricks is little bit inferior compared to shaft 1 since the former was ignited later and would be fully stabilized within a week.

Entrepreneur is still persisting with double chulha pattern since in this stacking and firing pattern there are no localized black spots due to overheating or under fired black cores. On inspection, no instances of firing shrinkage cracks or bloating were found. Thus the entrepreneur is self convinced about this firing pattern although the yield with respect to Datia pattern is round 5% less.

The most important learning is by seeing the dedication entrepreneur is performing VSBK detailing. All the batches from the two shafts are being unloaded exactly at the time prescribed by DA fire masters and supervisor. DA team had set the unloading rate at 12 batches per day to get quality material. Since entrepreneur has a very high stock of green bricks about 4 lakhs he wants to fire it off quickly so that it does not get damaged by occasional rains. At present he is thus unloading 16 batches per day. 

This he has done also after consultation with DA fire masters and supervisors. Undoubtedly the quality in terms of colour and ring will be inferior to 12 batch unloading. However entrepreneur is confident that he will be able to sell the above bricks at the same price. He has already sold approximately 80,000 bricks from his newly constructed VSBK at a price between Rs. 1100 to Rs. 1150 per thousand. This is the same as that of his clamp.