Analysis of clay brick cracks and solutions

1. Structural cracks

Brick structure cracks are caused by the molding process or improper raw material handling. This type of crack is different from the cracks caused by regular molding equipment (machine mouth). The biggest distinction is: molding cracks are regular to follow, while structural cracks are regular. It is not strong, but it is easy to misjudge such cracks as forming cracks in actual work. Pay attention to observation and judgment.

1. Two or more raw materials are not uniformly mixed, and the moisture content, plasticity, and particle gradation of various raw materials are different, and cracks appear after molding.

Solution: The raw materials must be mixed evenly before entering the crushing equipment, and do not place the raw materials mixing work on crushing, mixing, and screening equipment.

2. The influence of impurities in raw materials, such as tree roots, grass roots, plastic ropes, large hard materials, etc.

Solution: Check the screen frequently to prevent damage to the screen. After the subsequent equipment maintenance of the screen, the debris on the site should be cleaned up.

3. The water content of the mud entering the brick machine is different. The most typical case is that the mud in the belt and equipment is not cleaned up before the machine stops. After several hours of water volatilization of the mud, the mud moisture is uneven after the brick machine is turned on. Use the brick machine to stir and temporarily add water. Can\'t solve it.

Solution: When the forming work is completed, strictly follow the shutdown procedure to ensure that there is no excess mud in the belt and related equipment.

4. The knives of the mixer are severely worn or the mixing and adding water is unreasonable.

Solution: Regularly check the gap between the stirring knife and the box, and adjust the method of adding water.

5. The abrasion of the screw cutter of the brick machine is too large, the speed of each part of the extruded mud stick is unbalanced, and the density of the green body is inconsistent, resulting in different drying shrinkage and cracks.

Solution: Regularly check and replace the stirring knife in time.

6. Core frame problem. One is the unreasonable installation, and the other is the manufacturing problem of the core frame.

Solution: Adjust the core frame and replace the unqualified core frame.

7. After the mud stick is extruded, the machine mouth and the belt, the belt and the cutting machine and other transportation equipment are not evenly connected, which causes the mud stick to bend and produce cracks.

Solution: Adjust the balance of each equipment, and often clean up the mud attached to the belt idler.

2. Compression and tension cracks

It mostly occurs in the lower layer of the billet stack and on the horizontal billet, and this kind of crack generally appears large-mouth fracture on the surface of the billet. Causes and solutions of compression and tension cracks:

(1) The water in the green body is too high, and the green body strength is insufficient and fracturing.

Solution: reduce the forming moisture and increase the strength of the green body.

(2) The molding temperature of the green body is low. After entering the drying room, it absorbs moisture and softens, and then it rises sharply and shrinks and cracks.

Solution: Check the temperature of the green body frequently, especially the temperature of the mud bar during the extrusion of the machine mouth, and adjust the thermal parameters accordingly.

(3) The blank has poor plasticity, and the blank has low strength and fracturing.

Solution: Incorporate high-plasticity materials or add additives to improve the strength of the blank, or reduce the number of layers of the code blank.

(4) Uneven blending of plastic raw materials and other raw materials, resulting in uneven shrinkage of the green body and cracks.

Solution: Strengthen the pre-mixed processing of raw materials, make the blending uniform and consistent, so that the shrinkage is basically uniform.

(5) The plasticity of the mixture is too high, the linear shrinkage is too large, and it cracks after rapid drying.

Solution: Incorporate barren materials, such as coal gangue, slag, hard shale, etc. to reduce plasticity and reduce shrinkage.

(6) The number of kiln cars is small or the temperature of the bricks out of the kiln is high, and the bricks are stacked on a kiln car with a certain temperature, and rapid dehydration causes cracks.

Solution: Increase the number of kiln cars or adjust the sintering operation to reduce the temperature of the kiln. Kiln cars without pads can also add pads with large holes and easy heat dissipation.

(7) The uneven surface of the kiln car causes the brick to crack.

Solution: tidy up the countertop of the kiln car.

(8) The tunnel kiln or the turnover track is uneven, and the transportation of the kiln car is unstable, and fracturing due to shaking and shaking.

Solution: adjust the track.

(9) The jacking staff was inadvertently operating, and the car collided with the car during jacking, and the green body was broken or collapsed due to vibration.

Solution: Improve and improve operating skills.

Three, wind crack

Wind crack: This kind of crack usually occurs after the brick is formed before entering the drying kiln. The crack generally cracks laterally on the edge of the brick, such as hollow bricks around the hole and on the hole wall. There is also the upper windward side of the billet stack and the edge of the brick air duct with a large gas flow rate in the drying room.

The reasons and solutions are:

The main reason is the higher drying sensitivity of the mud. There are many plastic particles of this kind of mud, and its plasticity is high and it is easy to form. However, due to the unreasonable particle gradation, its sensitivity is relatively strong. When it is formed in strong wind, high temperature, and dry environment, wind cracking will occur. .

1. To solve wind cracks, first start with raw materials, adjust raw materials or proportions, and increase coal gangue or hard shale with low plasticity to adjust particle gradation and plasticity. Secondly, according to climate change, measures such as closing the doors and windows of the molding workshop and spraying water in time. The production line with conditions can also be set up with temporary or permanent drying and static stop lines, so that the bricks with high drying sensitivity can survive the \"dangerous period\" in an ideal environment.

2. The green body cracks as soon as it enters the drying kiln. The main reason is that the gas humidity in the drying kiln is low or the flow rate is high. It can reduce the exhaust air volume or lower the exhaust gas temperature and increase the humidity.

3. The gap between the upper blank in the drying chamber and the top of the drying chamber is too large, so that the hot gas in the drying chamber is concentrated on the upper part, causing the upper wind speed to be too high, and the temperature is too high to cause the blank to crack. The treatment method is to erect or artificially heighten the top bricks on the top of the billet stack. If the number of billet layers is not increased, add a windshield (board) on the top to reduce the upper gas velocity and flow. The windshield can be made of corrosion-resistant materials such as felt or concrete slabs.

4. The dry kiln is not tightly sealed, causing cold air to enter the kiln. It is necessary to check whether the kiln door, sand seal, kiln car bumper, etc. are tightly sealed at the entrance door. Do not open the dry kiln door for a long time. Close and seal immediately after entering the car.

5. The driving speed of the drying kiln is uneven, and the driving time is not controlled strictly. When the car is not driven for a long time, the temperature in the kiln is high and the humidity is low, which causes the green body to quickly dehydrate and crack. It is required to enter the vehicle regularly and evenly, and not to increase or decrease.

Parameters

1. Structural cracks

Brick structure cracks are caused by the molding process or improper raw material handling. This type of crack is different from the cracks caused by regular molding equipment (machine mouth). The biggest distinction is: molding cracks are regular to follow, while structural cracks are regular. It is not strong, but it is easy to misjudge such cracks as forming cracks in actual work. Pay attention to observation and judgment.

1. Two or more raw materials are not uniformly mixed, and the moisture content, plasticity, and particle gradation of various raw materials are different, and cracks appear after molding.

Solution: The raw materials must be mixed evenly before entering the crushing equipment, and do not place the raw materials mixing work on crushing, mixing, and screening equipment.

2. The influence of impurities in raw materials, such as tree roots, grass roots, plastic ropes, large hard materials, etc.

Solution: Check the screen frequently to prevent damage to the screen. After the subsequent equipment maintenance of the screen, the debris on the site should be cleaned up.

3. The water content of the mud entering the brick machine is different. The most typical case is that the mud in the belt and equipment is not cleaned up before the machine stops. After several hours of water volatilization of the mud, the mud moisture is uneven after the brick machine is turned on. Use the brick machine to stir and temporarily add water. Can\\'t solve it.

Solution: When the forming work is completed, strictly follow the shutdown procedure to ensure that there is no excess mud in the belt and related equipment.

4. The knives of the mixer are severely worn or the mixing and adding water is unreasonable.

Solution: Regularly check the gap between the stirring knife and the box, and adjust the method of adding water.

5. The abrasion of the screw cutter of the brick machine is too large, the speed of each part of the extruded mud stick is unbalanced, and the density of the green body is inconsistent, resulting in different drying shrinkage and cracks.

Solution: Regularly check and replace the stirring knife in time.

6. Core frame problem. One is the unreasonable installation, and the other is the manufacturing problem of the core frame.

Solution: Adjust the core frame and replace the unqualified core frame.

7. After the mud stick is extruded, the machine mouth and the belt, the belt and the cutting machine and other transportation equipment are not evenly connected, which causes the mud stick to bend and produce cracks.

Solution: Adjust the balance of each equipment, and often clean up the mud attached to the belt idler.

2. Compression and tension cracks

It mostly occurs in the lower layer of the billet stack and on the horizontal billet, and this kind of crack generally appears large-mouth fracture on the surface of the billet. Causes and solutions of compression and tension cracks:

(1) The water in the green body is too high, and the green body strength is insufficient and fracturing.

Solution: reduce the forming moisture and increase the strength of the green body.

(2) The molding temperature of the green body is low. After entering the drying room, it absorbs moisture and softens, and then it rises sharply and shrinks and cracks.

Solution: Check the temperature of the green body frequently, especially the temperature of the mud bar during the extrusion of the machine mouth, and adjust the thermal parameters accordingly.

(3) The blank has poor plasticity, and the blank has low strength and fracturing.

Solution: Incorporate high-plasticity materials or add additives to improve the strength of the blank, or reduce the number of layers of the code blank.

(4) Uneven blending of plastic raw materials and other raw materials, resulting in uneven shrinkage of the green body and cracks.

Solution: Strengthen the pre-mixed processing of raw materials, make the blending uniform and consistent, so that the shrinkage is basically uniform.

(5) The plasticity of the mixture is too high, the linear shrinkage is too large, and it cracks after rapid drying.

Solution: Incorporate barren materials, such as coal gangue, slag, hard shale, etc. to reduce plasticity and reduce shrinkage.

(6) The number of kiln cars is small or the temperature of the bricks out of the kiln is high, and the bricks are stacked on a kiln car with a certain temperature, and rapid dehydration causes cracks.

Solution: Increase the number of kiln cars or adjust the sintering operation to reduce the temperature of the kiln. Kiln cars without pads can also add pads with large holes and easy heat dissipation.

(7) The uneven surface of the kiln car causes the brick to crack.

Solution: tidy up the countertop of the kiln car.

(8) The tunnel kiln or the turnover track is uneven, and the transportation of the kiln car is unstable, and fracturing due to shaking and shaking.

Solution: adjust the track.

(9) The jacking staff was inadvertently operating, and the car collided with the car during jacking, and the green body was broken or collapsed due to vibration.

Solution: Improve and improve operating skills.

Three, wind crack

Wind crack: This kind of crack usually occurs after the brick is formed before entering the drying kiln. The crack generally cracks laterally on the edge of the brick, such as hollow bricks around the hole and on the hole wall. There is also the upper windward side of the billet stack and the edge of the brick air duct with a large gas flow rate in the drying room.

The reasons and solutions are:

The main reason is the higher drying sensitivity of the mud. There are many plastic particles of this kind of mud, and its plasticity is high and it is easy to form. However, due to the unreasonable particle gradation, its sensitivity is relatively strong. When it is formed in strong wind, high temperature, and dry environment, wind cracking will occur. .

1. To solve wind cracks, first start with raw materials, adjust raw materials or proportions, and increase coal gangue or hard shale with low plasticity to adjust particle gradation and plasticity. Secondly, according to climate change, measures such as closing the doors and windows of the molding workshop and spraying water in time. The production line with conditions can also be set up with temporary or permanent drying and static stop lines, so that the bricks with high drying sensitivity can survive the \"dangerous period\" in an ideal environment.

2. The green body cracks as soon as it enters the drying kiln. The main reason is that the gas humidity in the drying kiln is low or the flow rate is high. It can reduce the exhaust air volume or lower the exhaust gas temperature and increase the humidity.

3. The gap between the upper blank in the drying chamber and the top of the drying chamber is too large, so that the hot gas in the drying chamber is concentrated on the upper part, causing the upper wind speed to be too high, and the temperature is too high to cause the blank to crack. The treatment method is to erect or artificially heighten the top bricks on the top of the billet stack. If the number of billet layers is not increased, add a windshield (board) on the top to reduce the upper gas velocity and flow. The windshield can be made of corrosion-resistant materials such as felt or concrete slabs.

4. The dry kiln is not tightly sealed, causing cold air to enter the kiln. It is necessary to check whether the kiln door, sand seal, kiln car bumper, etc. are tightly sealed at the entrance door. Do not open the dry kiln door for a long time. Close and seal immediately after entering the car.

5. The driving speed of the drying kiln is uneven, and the driving time is not controlled strictly. When the car is not driven for a long time, the temperature in the kiln is high and the humidity is low, which causes the green body to quickly dehydrate and crack. It is required to enter the vehicle regularly and evenly, and not to increase or decrease.