Last issue we mainly discussed the mortar fullness of brick seam of inside tunnel kiln wall. This issue mainly describes the ash joint design of the refractory bricks and lightweight insulation bricks of the tunnel kiln wall.
The ash joint design requirements of refractory bricks and lightweight insulation bricks are less than 3mm, but due to the positive and negative dimensional deviations in the standard, the positive and negative deviations are sometimes greater than 3mm, such as ±2, which is greater than 3mm, then the gray seam can not be guaranteed to be less than 3mm. In order to meet the design requirements, we should first separate the same size refractory bricks and lightweight insulation bricks. When laying bricks, bricks of the same standard size can be built together to make the gray joints less than 3mm. Otherwise, the ash seam is larger than 3 mm. After the shrinkage, it is easy to cause a gap in the ash seam, so that the hot air flow is smashed outward during the positive pressure, which not only has a large heat loss but also affects the life of the kiln.
The design of the ash joint of the exterior wall brick masonry is less than 7mm. The same horizontal and vertical joints require the mortar to be full. The outer surface of the kiln wall is cemented with cement puree after the kiln is finished.
Building of refractory fire brick, insulation layer, insulation brick, and external wall b rick should be at the same time. Building step is from inside to outside.
This issue we mainly described the ash joint design of the refractory bricks and lightweight insulation bricks of the tunnel kiln wall. Hope this can bring help to furnace builders. Next issue we will continue to describe the building of insulation brick and laying of insulation layer. Please stay tuned.
