Production Process
Tunnel Dryer & Tunnel Kiln
one-step firing process pictures (stacking, dryer, kiln)
two-step firing process pictures (stacking, dryer, kiln)
one-step firing process refers to after forming green brick. Which Manual stack on the kiln cart into kiln or automatic stack on the kiln car.into kiln,directly into the kiln to fire till finished bricks process. Drying -firing simultaneously with only one stacking after forming . it is known as one-step firing process. There are two kinds for example Hoffman kiln one-step firing process Tunnel kiln one-step firing process, the former is smaller to use with more constraints, the latter is more popular.
two-steps firing process pictures: after forming the wet green,once stacking brick with drying by sun or manual drying,,then manual or automatic carry the dried brick to second stack on kiln cart or into the kilns for firing. Ther are two stacking times,once in drying, second in fring.it is called two-step firing process. There are two kinds for example Hoffman kiln two -steps firing process ,Tunnel kiln two-steps firing process, both are more popular.
How to choose the one-step firing process ?
a).material placitily index must be available.for exmple: the natural water content of the raw materials is less than 16%, the drying shrinkage is less than 3%, the drying sensitivity coefficient is less than 0.8. To stack the wet brick on the kiln cart or stack in kiln need to stack 9~15 layers to reach the production requirements, generally it is more suited to the shale and gangue materials, not suitable for High-volume fly ash material.
b) the wet green body strength cm2, or several under layers will fracture due to low strength. Wet blank must be semi-hard plastic or hard plastic extrusion, extrusion pressure must be more than 2.5MPa, the chamber vacuum is more than 80%, the raw material particles is equipped to be reasonable. is higher. to reach 2.5 ~ 2.8kg
c) product shape and structure is not complex. The product size is not too large, no more corners , the pore wall is not too thin, the hole shape can not be too complex ,which appropriate one step firing process.
How to choose the two-steps firing process ?
a) the two-steps firing process with drying by sun and hoffman kiln.to make solid bricks, more holes brick and low porosity of the hollow brick, it is seasonal production of the brick factory, in general, with plastic extrusion process.
(b)the two-steps firing process with small cross section tunnel type dryer ,hoffman kiln or tunnel kiln.When the product is solid brick, brick with many holes, modulus brick or hollow brick, the raw materials belonging to medium plasticity, dry linear shrinkage is more than 4% .with plastic extrusion process.
(c) the two-steps firing process with large cross section tunnel type dryer and tunnel kiln . When the high plasticity index of raw materials, drying sensitivity coefficient mor than 1, dry line incorporation rate, the product size is the bigger of thin-walled, porous (F, Banzhuan large thin-walled porous none load-bearing brick and firing hollow block) to use the process. the production process should be equipped with automatic stacking, automatic loading and unloading system, the high degree of automation in the process, with large investment , high quality staff, to make good quality brick products.