BRICK 523 



smaller chimneys or stacks. The furnace end of these flues would naturally be much 

 more highly heated than the upper end near the chimneys. To remedy this, the 

 floor is constructed of a greater thickness at the fire end, and gradually diminishes to 

 within a short distance of the top. By this means, and by the assistance of dampers 

 in the chimneys, it is kept at nearly an equal temperature throughout. Bricks that 

 will bear rapid drying, such as are made from jparly clays or very loamy or siliceous 

 earths, will be fit for the kiln in from 12 to 24 hours. Before the duty was taken off 

 bricks, much dishonesty was practised by unprincipled makers, where this drying 

 could be carried on economically. Strong clays cannot be dried so rapidly. These 

 sheds are generally walled round with loose bricks, stacked in between each post or 

 pillar that supports the roof. The vapour given off from the wet bricks, rising to the 

 roof, escapes. This system of drying is greatly in advance of that in the open air, for 

 it produces the ware, as made, without any deterioration from bad weather ; but the 

 expense of fuel to heat these flues has restricted its use to the neighbourhood of 

 collieries. In 1845 attention was turned to the drying of bricks, and experiments 

 carried out in drying the ware with the waste heat of the burning kilns. The caloric, 

 after having passed the ware in burning, was carried up a flue raised above the floor 

 of the shed, and gave off its spent heat for drying the ware. Although this kiln was 

 most useful in proving that the waste heat of a burning kiln is more than sufficient 

 to dry ware enough to fill it again, it was abandoned on account of the construction 

 of the kiln not being good. 



' Another system of drying is in close chambers, by means of steam, hot water, or by 

 flues heated by fire under the chambers. I will, therefore, briefly describe the steam- 

 chambor as used by Mr. Beart. This is a square construction or series of tunnels 

 or chambers, built on an incline of any desired length ; and at some convenient 

 spot near the lower end is fixed a largo steam-boiler, at a lower level than the drying 

 chamber. From the boiler the main steam pipe is taken along the bottom or lower 

 end of the chamber, and from this main, at right angles, runs branch pipes of four 

 inches diameter up the chamber, two feet apart, and at about three feet from the top 

 or arch. From there being so close and shallow a chamber between the heating surface 

 of the pipes and the top, and so large an amount of heating surface in the pipes, the 

 temperature is soon considerably raised. At the top and bottom ends are shutters or 

 lids, which open for the admission of the green ware at the upper end, and for the 

 exit of the dry ware at the lower end of the chamber. Over the steam-pipes are fixed 

 iron rollers, on which the trays of bricks, as brought from tLe machine, are placed, 

 the insertion of one tray forcing the tray previously put in further on, assisted in its 

 descent by the inclination of the construction. The steam being raised in the boiler 

 flows through the main into those branch pipes in the chamber, and from the largo 

 amount of exposed surface becomes condensed, giving of its latent heat. From the 

 incline given to the pipes in the chamber, and from the main pipe also having a fall 

 towards the boiler, the whole of the warm water from the condensed steam flows to 

 the boiler to be again raised to steam, sent up the pipes, and condensed intermittently. 

 The steam entering at the lower end of the chamber, it is of course warmer than the 

 upper end. Along the top end or highest part of the chambers is a series of chimneys 

 and windguards, through which the damp vapour escapes. The bricks from the 

 machine enter at this cooler end charged with warm vapour, and as the make proceeds 

 are forced down the chamber as each tray is put in. Thus, those which were first 

 inserted reach a drier and warmer atmosphere, and, on their arrival at the lower end, 

 come out dry bricks, in about 24 hours, with the strongest clays. In some cases the 

 waste steam of the working engines is sent through these pipes and condensed. Bricks 

 will dry soundly without cracking, &c., in these close chambers, when exposed to 

 much greater heat than they would bear on the open flue first described, or the open 

 air, from the circumstance of the atmosphere, although very hot, being so highly 

 charged with vapour. In practice, these steam-chambers have proved many principles, 

 but they are not likely to become universal, for they are very expensive in erection 

 on account of the quantity of steam-pipes, and involve constant expense in fuel, and 

 require attention in the management of the steam-boiler ; but their greatest defect 

 is the want of a current of hot air through the chamber to carry off the excess of 

 vapour faster than is now done. The attaining a higher degree of temperature in these 

 chambers is useless, unless there is a current to carry off the vapour. Why should 

 this piping bo used, or steam at all, when we have a large mass of heat being constantly 

 wasted, night and day, during the time the kilns are burning ? and after the process 

 of burning the kiln is completed, we have pure hot air flowing, from 48 to 60 hours, 

 from the mass of cooling bricks in the kilns, free from carbon or any impurities ; this 

 could be directed through the drying chambers, entering in one constant flow of hot, 

 dry air, and escaping in warm vapour. The waste heat during the process of burning 

 can bo taken up flues under the chamber, and thereby all the heat of our burning 



