Checker bricks for Hot-blast Stove

Checker bricks are a heat storage carrier used in thermal equipment. They are mainly used in the middle and upper parts of the regenerator of hot blast furnaces to store heat. In the process of heating cold air into hot air, the regenerator is the most important part of the hot blast furnace, so the checker bricks are also critical.

Types of checker bricks

According to the technical requirements of different temperature zones, cărămizi înalte de alumină, siliceous checker bricks, and clay bricks are generally used. In some hot blast stoves, cărămizi de mullit, și cărămizi de sillimanit are also selected.

High alumina checker refractory bricks

Brand index	DRL-135	DRL-145	DRL-150	DRL-165	DRL-155	DRL-48
Al2O3, % ≥	70	75	80	65	55	48
refractoriness℃ ≥	1790	1790	1790	1790	1770	1750
Normal temperature compressive strength MPa ≥	20	20	19	24	24	24
Normal temperature compressive strength MPa ≥	65	70	80	49	44.1	39.2
Reheat line change rate % ≥	±0.1	±0.1	±0.1	+0.1~-0.4	+0.1~-0.4	+0.1~-0.4
	1450℃x2h	1500℃x2h				1450℃x2h
0.2MPaLoad softening start temperature ℃ ≥	1500	1550	1650	1500	1470	1420
High-temperature creep rate % ≤	0.6 1350℃×50h	0.6	0.7	–	–	–
		1450℃×50h	1500℃×50h	–	–	–

Silica refractory checker brick

project	General silica brick			Silica bricks for hot blast stove
牌号	GZ-95	GZ-94	GZ-93	Vault furnace bricks		Checker brick
SiO2≥	95	94	93	95	96	95	96
Fe2O3 ≤	1.2	1.4	1.5	1.0
Fire resistance temperature ℃ ≥	1710	1710	1690	1710	1710	1710	1710
0.2MpaLoad softening start temperature℃ RUL≥	1650	1640 (胶结硅石1620)	1620	1650	1660	1650	1660
Apparent porosity AP% ≤	22	23	25	22	22	22	22
Normal temperature compressive strength CCS MPa≥	29.4	24.5	19.6	35	40	30	35
True Density g/cm3≥	2.37	2.38	2.39	2.35
High temperature creep rate %≤				0.8
Thermal expansion rate %≤				1.26

How to choose checker bricks?

The selection of checker bricks has a great influence on the operation of the hot blast stove. The working effect and heat transfer efficiency of the regenerator are closely related to the size, shape, and brick quantity of the checker brick holes. Here are some factors to consider when choosing checkered tiles

1. Checker brick has the largest heating area per unit volume
2. There should be an amount of bricks suitable for the heating area to store heat to ensure that it does not cause an excessive drop in wind temperature within a certain range.
3. Cause airflow disturbance as much as possible, maintain a high flow rate, and increase convective heat transfer and speed.
4. Have sufficient building stability
5. Easy to process, manufacture, install, and maintain at low cost.

Arrangement requirements for holes in refractory chequers

1. All hole widths should be equal. The holes are staggered in one or two directions.
2. ​The holes should be arranged symmetrically up and down, left and right, and distributed evenly. The length direction of the hand-gripping holes should be parallel to the strips of the bricks.