Stable thermal and pressure control is the core of high-quality fired brick production in a tunnel kiln. The automatic control system coordinates multiple functional units to govern airflow, oxygen supply, heat recovery and pressure sealing. Understanding how the exhaust fan, hot air extraction fan, kiln car bottom sealing system and hatch dampers interact helps brick manufacturers stabilize firing curves, cut coal consumption and reduce defective underfired bricks.

The exhaust fan is the master airflow driver of the whole kiln system. It draws flue gas sequentially through the cooling zone, soaking zone, firing zone and low-temperature preheating zone via hatch dampers. Airflow moves opposite to the travel direction of green bricks. Two core purposes are served: delivering oxygen to sustain coal combustion in the firing zone, and sending waste hot flue gas to dry green bricks in the drying chamber.

In the low-temperature preheating section, flue gas preheats green bricks until embedded coal ignites. Combustion raises the temperature to the peak firing point. The air volume must match coal feed to maintain proper oxygen level, ensuring 70%–80% of internal coal burns out in the firing zone. If airflow is insufficient, incomplete combustion generates limited heat, leading to an uneven fire line. Excessive airflow carries excessive heat away, dragging down the overall kiln temperature.

Working independently, the hot air extraction fan extracts sensible heat purely from the cooling zone for brick drying, with no oxygen supply for combustion. Any rise in hot extraction volume pulls heat out faster, lowering temperature across cooling, soaking, firing and preheating zones. Reduced extraction retains more heat inside the kiln. Its airflow direction opposes the exhaust fan, which means hot extraction competes for airflow capacity and can pull down kiln temperature. A high hot extraction rate near the firing zone will halt fire propagation and trigger overfiring in the brick stack center. When cooling blower supply stays fixed, over-extraction can create oxygen shortage for combustion.

Pressure sealing relies on the kiln car bottom channel and sand seal system. Wind baffles and coarse sand troughs separate the under-car air duct from the kiln interior. Once pressures balance between the car bottom and kiln chamber, cross air leakage stops. Upward leakage causes underburnt bricks; downward leakage burns kiln car metal structures. The safe temperature range for the kiln car bottom is 70℃ to 100℃.

Mung-bean-sized coarse sand is preferred for sand seals. Fine sand gets blown away easily, while coarse sand is continuously distributed by kiln car baffles to seal the trough tightly, preventing air bypass.

Pressure balance is maintained by balance fans paired with pressure transmitters. Traditional tunnel kilns running under full negative pressure use suction-type balance fans. Discharge-end cooled tunnel kilns feature negative pressure in preheating zones and positive pressure in cooling zones, requiring one suction fan and one blower fan for dual-section balance. Variable frequency drives adjust fan flow based on real-time pressure feedback from two monitoring points, synchronizing car-bottom pressure with kiln pressure. Mechanical balance gates can create negative pressure but lack automatic adjustment capacity and cannot operate in positive-pressure sections.

Low-temperature preheating hatch dampers control kiln positions No.1 to No.10 up to 560℃. The collective opening of these dampers controls total system airflow, while different opening combinations tune local temperature distribution.

The maximum lift of each hatch damper equals its radius. The required damper quantity is calculated by taking the square of the ratio between main duct diameter and single damper diameter. For a 1.2 m main flue and 0.4 m damper, the ratio equals 3, requiring 9 fully open dampers, or 18 dampers (9 pairs) running at half opening. This configuration minimizes pressure loss across dampers.

When fans are controlled by VFDs, operators should fully open damper passages to avoid wasting fan pressure on throttling resistance. Damper profile and opening directly decide fire speed and production capacity. Standard bricks, perforated bricks and hollow bricks require separate damper schedules. Settings also change for wet green bricks and pre-dried green bricks. If fan minimum speed still brings overly fast fire movement, damper pattern and opening should be revised to stabilize drying air pressure and flow.

The thermal principle of hatch dampers is simple: more hot flue gas passing through a damper position means longer heat exchange and higher local brick temperature.

Tunnel kilns are widely used in the brick firing sector to produce fired brick and various kiln products. The kiln car frame and sand sealing plate, manufactured from castings or steel sheets, work under continuous high-temperature atmosphere. These components are exposed directly to hot gas inside the kiln. If they cannot withstand thermal expansion deformation and thermal oxidation corrosion, the thermal tightness of the kiln car will deteriorate rapidly after long operating hours.

Defective kiln cars cause frames to lose support for groove bricks. Kiln car shaking during travel destabilizes the whole firing process. The bricks suffer abnormal deformation and cold cracks, lowering finished product quality. Once such problems emerge during kiln running, immediate on-site repair is impossible. Production has to continue until kiln shutdown. In extreme cases, groove bricks lose balance and the kiln car frame collapses, damaging the main kiln body, kiln bed, wheels and rail system.

When thermal tightness of sand sealing plates fails, high-temperature gas escapes through gaps between the kiln wall and kiln car side panels into the undercarriage. This creates uneven temperature distribution inside the tunnel kiln, leading to inconsistent firing and cold cracking of bricks. Kiln wheels and rails also suffer accelerated wear. These faults cannot be repaired online, so production must keep running until kiln stop.

To solve these typical problems in brick firing production, we carried out multiple structural improvements on the kiln car system. Our target is to enhance refractory performance, durability, and thermal tightness, with durability as the core optimization objective. These upgrades have achieved satisfying application results.

Detailed Improvement Solutions

1. Kiln Car Main Body Structure Optimization

The kiln car assembly consists of metal frame, groove bricks, supporting protrusions on the frame, sand sealing plates covering the lower side of groove bricks, and thermal insulation layers laid inside groove bricks. The metal frame functions as the load-bearing skeleton.

Removable sand sealing plates are vertically fixed on the end face of the kiln car frame. Mounting bases on both lower ends of the frame support vertical installation. The sand sealing plates run from front to rear on both sides of the kiln car. Their top edge covers the bottom part of groove bricks and frame end face.

Protrusions parallel to the travelling direction of the kiln car are arranged slightly inward above the frame. Groove bricks are placed between these protrusions and fixed sand sealing plates. Groove bricks connected along the moving direction form two side walls of the kiln car, preventing hot gas from leaking backward to the undercarriage area.

Vertically mounted sand sealing plates support the bottom outer wall of groove bricks and cover frame end surfaces. This structure separates the metal frame from direct contact with high-temperature gas, preventing thermal expansion deformation and thermal oxidation corrosion. A refractory insulation layer on top of the frame forms part of the kiln bed. Together with side wall structures, it blocks hot gas from penetrating downwards.

2. Assembled Refractory Panel Type Sand Sealing Plate

The sand sealing plate is assembled by two or more refractory panels, vertically mounted and easy to disassemble. It covers the bottom of groove bricks and both end faces of the frame. This setup protects the metal frame from direct high-temperature impact. When individual refractory panels get damaged and thermal tightness drops, the tunnel kiln can keep operating. Damaged refractory panels can be replaced conveniently during maintenance.

3. Gap Sealing with Fiber Felt Materials

Fiber felt sealing materials are filled in all connecting gaps: sand sealing plate and groove brick joints, mounting gaps between sand sealing plates and frame, groove brick and frame contact areas, groove brick and protrusion gaps, protrusion and insulation layer joints, insulation materials and frame gaps, and seams of multi-piece assembled sand sealing plates. This sealing design further stops hot gas leakage into the undercarriage.

4. Embedded Groove Brick Anti-slip Construction

Groove bricks adopt embedded structures matching the frame protrusions. Embedded connection locks groove bricks firmly to avoid sliding. The detachable vertical sand sealing plates cover both ends of the frame. The metal frame will not touch high-temperature gas directly. Even partial refractory panels are damaged, kiln operation can continue and component replacement is convenient.

5. Refractory Ceramic Coating for Metal-based Sand Sealing Plates

For metal-made sand sealing plates, refractory ceramic coating can be applied on the surface. Thin metal sheets with refractory ceramic coating can deliver the same anti-deformation and anti-thermal oxidation performance.

The production of fired wall materials is a systematic project composed of interconnected process stages. Every production segment works like a wooden plank for a water bucket. The maximum water capacity of the bucket is limited by the shortest plank rather than the longest one. Similarly, the profitability of a brick production line is determined by its weakest process link, which we call the short board principle for brick plants.

Many brick factory owners focus only on nominal production capacity at the planning stage. They immediately ask for daily output of 500,000 or 800,000 pieces, annual capacity of 150 million or 200 million fired brick. However, few calculate the actual total material turnover volume on site. The real daily turnover may reach 5 million to 8 million pieces, far higher than the nominal brick output.

Raw Material Stockyard

Some plants use local gangue and shale without extra storage yards. If raw materials are transported from elsewhere, you need multiple stockyards capable of holding 500,000 pieces of brick raw materials.

Raw Material Processing

The daily raw material processing capacity must exceed the target daily brick output, and equipment operation time is only 8–10 hours. Operators need to select crushers, roller screens, single-stage or two-stage crushing solutions according to raw material hardness and moisture content. You also need to confirm belt conveyor width, running speed, magnetic separator configuration and easy maintenance design. Even with large crushers and powerful motors, replacing hammerheads for half a day or one day will directly cut your output. Many small brick plants rely on loaders and manual lifting for heavy screen plates, lacking overhead cranes. Frequent turnover of maintenance staff becomes a typical production short board.

Aging Storage and Fine Material Silo

Aging silos play a vital role in brick manufacturing. The recommended storage capacity supports 3 times daily output with 72-hour aging time. It can maintain raw material supply even when crushing equipment is shut down for 2 days. For hard or sandy raw materials, waterproof design prevents uneven moisture (dry top, wet bottom). Installing soil kneaders after aging and mixing helps stabilize raw material performance.

Extrusion and Forming

The whole extrusion forming system includes feeding, mixing, intensive stirring, extrusion, cutting and brick stacking. The vacuum extruder and brick stacking machine performance varies greatly with raw material properties and product positioning. One set of equipment may work well in one region but fail in another. A typical case: many brick plants in Lanzhou copied production experience from central and eastern China. They obtained fine green bricks, but suffered slow drying, slow firing, high reject rate and cracking. Their actual firing output was much lower than expected, creating a serious short board.

Drying Chamber

Multiple configurations are available for tunnel kiln: direct drying & direct firing, one drying + one firing, one drying + two firing, two drying + one firing, etc. The best option depends on raw materials, finished products and local climate. Direct drying and direct firing suits plastic shale or coal gangue for solid bricks. But for raw materials with high drying sensitivity, direct drying & direct firing will become an irreversible short board.

Special climate also brings challenges. In Kuitun, Xinjiang, extremely dry air causes green body cracking right after cutting. The solution includes lowering the height of workshop and green brick shelter, using curtains to raise ambient humidity and adopting 1.5x brick stacking layout. The track and kiln car quantity must also increase by 1.5 times.

Drying heat sources include flue gas drying, waste heat drying and combined flue gas & waste heat drying. If raw materials contain high sulfur, flue gas drying will cause secondary pollution and increase environmental costs. Low-sulfur raw materials benefit most from combined drying, which saves power and fuel.

Moisture exhaust methods include centralized exhaust, decentralized exhaust, sectional centralized exhaust, positive pressure and negative pressure exhaust. Pure centralized moisture exhaust is inefficient with high power consumption and excessive oxygen. The optimal scheme combines decentralized and centralized exhaust, dominated by positive pressure and assisted by negative pressure. Many rotary tunnel kiln projects have defective drying chamber design; some moisture exhaust fans consume 3–4 times power of the tunnel kiln itself.

Firing Process

Kiln performance, product quality and coal consumption are basically determined in kiln design and construction stage. There are masonry tunnel kilns, combined tunnel kilns, upper air duct kilns, lower air duct kilns and rotary tunnel kilns. Rotary tunnel kilns hold about 300 standard bricks per cubic meter, while traditional tunnel kilns can hold 400–500 pieces. Traditional tunnel kilns are limited by structural defects: bricks move while kiln stays static, leading to cross-section temperature difference and kiln car burning. Overcoming this long-existing structural weakness requires technological innovation.

Firing Technician Capability

Many operators mistakenly regard kiln firing as simply watching flame. A qualified kiln operator must be a kiln adjuster. He needs to master kiln structure, air flow, waste heat, fan volume, temperature, heat value, brick stacking plan, kiln car and drying chamber parameters.

There is a well-known rule: 70% performance comes from brick stacking, 30% from firing; 70% work under the kiln, 30% above the kiln. Excellent technicians analyze raw material test reports and heat distribution. Never feed coal at kiln car joints in high-temperature zones, or open fire holes here, which will damage kiln cars severely. Kiln car burning also relates to kiln car insulation and air balance in trenches.

Loading Lane

One real case: a 3.7m width kiln with 4 drying + 3 firing zones only has one loading lane with semi-automatic packing machine. No extra space can be reserved for additional lanes. The factory could never run full 4-drying-3-firing mode after 5–6 years of operation; maximum operation is only two firing zones. Insufficient loading lanes block finished brick delivery, which is a hard-to-fix planning short board. The number of loading stations, packing stations and holding stations must be calculated in advance according to target output.

Finished Product Yard

Finished storage yard is ignored by many brick plants. Limited yard space plus large kiln capacity leads to production reduction in rainy seasons or off-seasons. Hollow bricks require larger storage yards. Lack of yard space becomes a tough short board for hollow brick manufacturing.

Raw Material & Environmental Compliance

Many factories skip raw material lab testing before construction. Raw materials with 4%–5% sulfur without alternative sources will become an insurmountable short board under environmental regulations. Multiple lab tests are required before investment. High calcium content causes deliquescence; high potassium oxide and magnesium oxide trigger efflorescence and white salt bloom on brick surface.

Desulfurization Tower

Many brick plants rebuilt desulfurization towers because suppliers lack knowledge of kiln structure and fluid mechanics. Poorly designed desulfurization equipment increases fan load, hinders moisture exhaust and reduces output. Horizontal plus vertical flue desulfurization & dust removal performs better than single vertical type. The air inlet of desulfurization tower set slightly above kiln surface saves power and fits fluid mechanics rules.

Environmental Protection and Kiln Upgrade

Natural gas firing delivers clean production with low sulfur, nitrogen oxide and dust pollution. Factory owners need to evaluate whether existing kilns can be modified for natural gas combustion without full reconstruction. New kiln projects should consider fuel options in early design.

Conclusion

The full-cycle capacity formula for tunnel kiln production:

1. Raw material stock: multiple times of daily output
2. Raw material processing capacity ≥1.5× daily output
3. Aging capacity: 2–3× daily output
4. Extruding within 8–12h to reach 1× daily output
5. Green brick storage:1.5–2× daily output
6. Empty kiln car ≥0.5× daily output
7. Drying capacity:1× daily output
8. Firing capacity:1× daily output
9. Finished brick transport lane ≥0.75× daily output
10. Loading station ≥0.3× daily output
11. Finished yard: multiple times daily output

The whole system maintains turnover of dozens of times nominal daily output. A plant targeting 500,000 bricks per day may need 5 million bricks in total turnover.

Fired wall material manufacturing is a complete system covering raw material preparation, processing, extrusion, stacking, green brick drying, firing and finished product handling. Profitability of your brick factory is determined by the weakest link.

In modern brick manufacturing plants, environmental standards and energy costs have become two major challenges for factory owners. One of the key factors affecting kiln energy consumption and emission performance is the oxygen content in tunnel kiln exhaust gas.

Many brick factories try to reduce exhaust oxygen levels by simply adjusting fans, air pressure, or damper openings. However, the real solution requires a systematic understanding of tunnel kiln air management.

By eliminating unnecessary air, reducing air leakage, and optimizing combustion air supply, brick factories can achieve better fuel efficiency, more stable firing quality, and lower environmental emissions.

This article explains how the three principles of correct air usage, reducing useless air, and optimizing reasonable airflow can help improve modern fired brick production processes.

1. Why Exhaust Oxygen Content Matters in Brick Manufacturing

During the fired brick making process, combustion requires a certain amount of oxygen to ensure complete fuel burning. However, excessive air entering the kiln does not improve combustion efficiency. Instead, it increases the amount of exhaust gas and raises the oxygen content measured in the kiln exhaust.

High oxygen content in exhaust gas usually indicates:

•   -Excessive air entering the tunnel kiln
•   -Heat loss caused by unnecessary airflow
•   -Higher exhaust temperature
•   -Increased energy consumption
•   -Difficulty meeting environmental monitoring requirements

For this reason, controlling oxygen content in kiln exhaust gas has become an important indicator for improving energy-saving brick production.

2. Eliminate Incorrect Air: The First Step of Tunnel Kiln Optimization

Clay brick manufacturing remains one of the most fundamental segments of the global building material industry. Many brick manufacturers face a common challenge: limited workshop space when upgrading or building new clay brick production lines. Traditional brick making equipment, especially horizontal brick cutters, requires large floor areas, which restricts factory expansion and raises workshop construction costs.

For small-to-medium brick factories and newly built compact production workshops, space utilization directly affects overall project investment and long-term operational efficiency. Choosing space-saving core machinery becomes a key decision point in the whole brick plant design.

The Automatic Vertical Brick Splitter Cutter is a core piece of equipment specially developed to solve the space shortage problem in brick workshops. It is designed for precise vertical cutting of extruded mud columns and separates continuous mud extrusions into individual brick green bodies.

Different from conventional horizontal brick cutters, this vertical cutting structure greatly reduces the occupied floor space. It works synchronously with brick extruders in the production line, perfectly fitting compact brick factory layouts.

Core Benefits

✅ Space Optimization: Vertical cutting design saves workshop floor area, ideal for factories with limited land.

✅ Stable Matching with Extruders: Connects directly after extruders to process continuous clay mud columns.

✅ Flexible Integration: Easy to install into both new brick production lines and old production renovation projects.

FAQ

Q1: What is the function of vertical brick splitter cutter in clay brick production line?

A: It performs precise vertical cutting on extruded mud columns and cuts the continuous clay extrusion into standard-sized brick green bodies.

Q2: Can vertical brick cutting machine be used for old brick factory renovation?

A: Yes. Its compact footprint makes it a good option for upgrading existing production workshops with limited available space.

Q3: What is brick green body in brick manufacturing?

A: Brick green body is the unfired raw brick before entering the drying chamber and tunnel kiln for sintering.

Q4: What equipment works together with vertical brick splitter cutter?

A: It is normally matched with clay brick extruders, and forms a complete mud extrusion and cutting unit.

Clay fired bricks and blocks are core load-bearing and filling materials for modern construction projects, and their stable quality is the premise of engineering safety and long-term use. With the popularization of intelligent tunnel kiln firing technology, modern brick-making enterprises mainly produce fired porous bricks and hollow blocks, replacing traditional backward firing processes. However, various quality defects still occur in mass production due to improper raw material processing and unscientific process parameter setting.

Industrial production practice verifies that the quality of fired brick products depends on three core links: raw material pretreatment, firing process control and on-site production management. Ancient brick-making technology emphasized fine raw material processing, and modern industrial production also proves that more than 70% of fired brick quality problems stem from non-standard raw material treatment. Based on years of wall material reform and production debugging experience, this article summarizes targeted improvement measures for six major common defects in fired brick production, providing practical guidance for brick factory quality control and production optimization.

1. Unqualified Dimensional Tolerance

Uneven raw material particle size and insufficient aging period are the main causes of unqualified brick dimensional tolerance. Raw materials without aging treatment have poor plasticity, which leads to unstable mud strip extrusion and irregular brick molding sizes.

To solve this problem, manufacturers must carry out professional particle screening and grading to uniform raw material fineness. The raw material aging cycle should be guaranteed for no less than 7 days to improve plasticity stability. Meanwhile, adjust the outlet specification of the brick extruder according to the actual plasticity index of raw materials, so that the molded brick size meets industrial standard tolerance requirements.

2. Corner Crack Defects

Excessive coarse particles in raw materials and low molding moisture will increase extrusion resistance during brick molding, resulting in frequent corner and edge cracks of finished fired bricks.

The optimization measures include reducing sieve aperture to improve raw material crushing fineness, adjusting the high-speed roller gap to 3mm for refined crushing, and appropriately increasing raw material moisture content to reduce extrusion resistance, so as to avoid corner crack formation fundamentally.

3. Horizontal Shrinkage Cracks on Brick Ribs and Walls

Fired hollow bricks and multi-hole blocks are prone to horizontal cracks on ribs and walls. On the one hand, uneven raw material particle gradation causes inconsistent shrinkage of different particles; on the other hand, excessive drying temperature and rapid drying speed in the drying kiln will accelerate surface shrinkage and produce cracks.

Enterprises need to optimize raw material particle matching to balance shrinkage performance. Strictly control the drying kiln temperature at 40℃ (inlet) and 110℃ (outlet). Adjust fan speed and drying duration according to kiln internal temperature and humidity to realize balanced drying of green bricks.

4. Low-strength Under-fired Bricks

Under-fired bricks with low strength and pale color are typical defects in tunnel kiln production, mainly appearing at the bottom of kiln cars. Cold air leakage caused by loose kiln car sealing breaks the kiln internal temperature balance, coupled with unbalanced kiln pressure, insufficient raw material heat value and compressed firing time, forming under-fired products.

Effective solutions: Repair kiln car sand seal and sealing grooves regularly to block cold air leakage. Optimize the pressure balance of each temperature zone in the tunnel kiln to reduce temperature difference. Adjust raw material heat proportion and extend firing and heat preservation time as required, adhering to standardized firing process rather than blind capacity expansion.

5. Over-fired Burst Bricks

Excessively high raw material heat value, unreasonable brick stacking gaps and delayed process adjustment of firing zones will lead to overheating deformation, bubbling and bursting of bricks in the upper and middle layers of brick stacks.

Manufacturers need to dynamically adjust raw material heat proportion to avoid heat excess. Optimize green brick stacking technology to increase heat circulation gaps. Precisely control firing cycle to prevent over-fired burst brick defects.

6. Substandard Weathering Durability

Insufficient raw material aging and homogenization treatment lead to incomplete firing reaction of brick bodies. Even under standard firing temperature, raw material particles cannot complete solid-liquid phase fusion, resulting in poor weathering durability and short service life of finished bricks.

The improvement methods are as follows: Complete raw material homogenization and long-term aging pretreatment. Properly increase firing temperature to promote full particle reaction. Improve crushing fineness of low-quality raw materials to ensure overall firing uniformity.

The Future of Brick Manufacturing: Automation Drives the Development of Modern Brick Factories

The brick manufacturing industry has been developing for thousands of years, but modern construction requirements have created new challenges for brick producers. Customers today demand bricks with better appearance, higher strength, accurate dimensions, and consistent quality. At the same time, brick manufacturers are looking for ways to reduce labor dependence, improve production efficiency, and achieve more stable operation.

With the development of intelligent manufacturing technology, traditional manual brick handling processes are gradually being replaced by automatic brick production solutions. Among these technologies, the automatic loading and unloading system has become an important part of advanced brick production lines, especially for manufacturers producing high-grade face bricks, hollow bricks, and premium wall materials.

Challenges Facing Traditional Brick Production

In traditional brick factories, many processes rely heavily on manual operation, especially during:

•   -Green brick handling
•   -Brick stacking
•   -Pallet transportation
•   -Dry brick unloading
•   -Brick setting before firing

Manual operation can create several production challenges:

1. Inconsistent Brick Arrangement

High-quality bricks require accurate positioning during drying and firing. Small differences in spacing or placement may influence the final product appearance.

2. Higher Labor Requirements

Large-scale brick plants need continuous operation. Manual loading and unloading require more workers and increase operational pressure.

3. Lower Production Stability

Human operation speed and accuracy may vary, which can affect the consistency of the production process.

Therefore, modern brick factories are increasingly adopting industrial automation systems to improve production reliability.

What Is an Automatic Loading and Unloading Twice Stacking System?

The Automatic Loading and Unloading Twice Stacking System is an advanced automation solution designed for modern clay brick manufacturing plants and high-grade wall material production lines.

This system completes multiple processes automatically, including:

•   -Green brick cutting and grouping
•   -Pallet loading
•   -Pallet transportation
•   -Temporary storage
•   -Dry brick unloading
•   -Brick grouping and spacing
•   -Automatic setting preparation

The complete system is controlled by an intelligent PLC control system, which coordinates different production units and allows automatic parameter adjustment through industrial computer technology.

How Does Twice Stacking Technology Improve Brick Production?

The biggest advantage of a twice stacking system is that bricks can be separately arranged during drying and later transferred for firing preparation.

This production method provides several benefits:

1. Better Surface Quality

For premium face bricks, surface appearance is extremely important. Separate pallet drying helps reduce contact marks and improves the finished brick surface quality.

2. Higher Production Accuracy

The automatic positioning system ensures accurate brick arrangement, reducing mistakes caused by manual handling.

3. Improved Factory Efficiency

By connecting multiple processes into one automated system, factories can achieve smoother production flow and reduce unnecessary manual operations.

Key Advantages of Automatic Brick Handling Equipment

-High Automation Level

The system integrates transportation, loading, unloading, grouping, and setting processes into one complete solution.

-Stable Production Performance

Servo positioning technology and intelligent control help maintain accurate operation during continuous production.

-Flexible Production Options

The system can be customized according to:

•   1. Brick type
•   2. Production capacity
•   3. Drying method
•   4. Factory layout

Suitable for High-Grade Brick Production

It is widely suitable for:

•   1. Face bricks
•   2. Hollow bricks
•   3. Clay blocks
•   4. Premium wall materials

Running a profitable fired brick manufacturing factory requires systematic thinking of the whole brick production line. Every procedure, starting from raw material mining to finished brick stacking, connects tightly. Just like the bucket analogy: the total holding volume is controlled by its shortest plank. In brick manufacturing, your factory’s profitability is limited by the weakest process segment.

Most brick investors focus merely on headline daily or annual brick output during planning. For instance, they target 500,000 or 800,000 bricks per day. Yet they ignore total internal material turnover. For a nominal daily output of 500,000 bricks, the whole factory may circulate up to 5 million bricks of raw materials and green bodies in the whole system. Let’s break down typical weak points in brick manufacturing.

Raw Material Storage & Raw Material Preparation

On-site mining of coal gangue or shale saves the cost of large raw material yards. If raw materials need transportation from remote mines, multiple stockyards are necessary to guarantee stable feeding for your brick making machine.

Raw material crushing workshop only operates 8–10 hours daily, so its processing capacity must exceed your designed daily brick output. Engineers need to decide crushing stages, mixer type, sieve specification, conveyor speed and magnetic separator layout. Maintenance accessibility is easily overlooked.

Many brick plants use manual handling for heavy screen plates because they have no overhead crane. Replacing crusher hammerheads takes a long time, and mechanic turnover is high. This slows down your actual production rate heavily.

Aging Bin & Raw Material Homogenization

Aging treatment stabilizes raw material plasticity. A proper aging chamber holds raw materials enough for 72 hours of production. When crushing equipment stops for repair, aged raw materials can keep production running.

Sandy and hard rock raw materials require anti-seepage design inside aging bins to avoid uneven moisture distribution. Adding soil shredder after aging mixing improves raw material consistency for extrusion.

Green Body Extrusion, Cutting and Setting

Extrusion, mixing, cutting and setting are core sections for brick green body. Equipment performance varies under different raw materials and local climates.

One real case: brick factories in Lanzhou adopted process parameters from central China. Green bodies looked good after extrusion, but drying speed was low, cracking rate high and final output far below expectation. Raw material difference created a hard-to-solve bottleneck.

Drying Chamber Design & Moisture Exhaust

Various tunnel kiln for brick firing combinations exist with different drying and firing zone layouts. Raw material plasticity, shrinkage sensitivity and local climate determine which layout fits you best.

For drying-sensitive raw materials, direct drying direct firing kiln is not recommended. In dry regions like Kuitun Xinjiang, low air humidity causes green body cracking immediately after cutting. Raising local humidity in green body storage area and increasing kiln car quantity can solve the cracking problem. Drying heat sources include flue gas drying, waste heat drying and combined drying. High sulfur raw materials cannot use flue gas drying, as sulfur pollutants will contaminate finished bricks and raise environmental expense. Combined flue gas and waste heat drying saves fuel and power for low-sulfur raw materials.

For moisture exhaust design: pure centralized exhaust has high power consumption and poor effect. The optimized scheme combines decentralized and centralized exhaust, positive pressure as primary and negative pressure auxiliary. This reduces green body collapse risk and energy consumption. Many rotary tunnel kilns have poorly designed drying sections with extremely high fan power consumption.

Kiln Type Selection & Firing System

Multiple kiln types are available for fired brick production line: masonry tunnel kiln, combined tunnel kiln, rotary tunnel kiln and different flue structure tunnel kilns.

Rotary kiln has about 300 bricks per cubic meter loading capacity, while tunnel kiln can load 400–500 bricks per cubic meter. If we can overcome cross-section temperature difference and kiln car burning defects of conventional tunnel kilns, tunnel kilns will deliver superior output and energy efficiency. The classic structural bottleneck of tunnel kiln is that bricks move while kiln shell remains fixed. New technical innovation is needed to tackle this issue.

Kiln Operator Training & Brick Setting Technology

Many firing workers misunderstand kiln operation as only observing flame color. A professional kiln operator must understand air flow, kiln structure, waste heat system, temperature monitoring and brick setting strategy. Poor operator skill is repairable by professional training.

A well-known rule in brick industry: brick setting accounts for 70% of firing results, while firing operation only accounts for 30%. Good kiln operators analyze raw material test reports and heat distribution to optimize brick setting scheme. Factory operators are prohibited to add coal at kiln car joints and open fire holes at high-temperature zones, which will burn kiln cars. Kiln car burning is also affected by insulation and air balance in the trench, a common pain point for brick manufacturers.

Unloading Track, Finished Yard and Factory Layout

A brick factory with 3.7m wide kiln designed for four drying three firing only equipped one unloading track, without space for expansion. It could never reach designed capacity, limited by insufficient unloading tracks. The quantity of unloading positions, packing stations and kiln car parking positions must be calculated in the initial design. This layout defect is hard to fix after factory construction.

Insufficient finished brick yard is another widespread bottleneck. Factories with limited storage space need to reduce production in rainy season. Hollow brick production heavily depends on finished yard space, because construction projects order hollow bricks for later installation.

Raw Material Test & Environmental Protection

Pre-construction raw material testing is essential. Raw materials with 4–5% sulfur bring huge environmental pressure without alternative raw materials. High calcium content causes brick deliquescence; high potassium and magnesium lead to efflorescence (white bloom) on brick surface.

Many factories rebuilt desulfurization towers twice. Desulfurization suppliers often lack kiln fluid mechanics knowledge. Improper tower design leads to poor moisture exhaust and output drop. Horizontal plus vertical combined desulfurization and dust removal performs better than single vertical tower. The air inlet slightly above kiln surface saves power.

Natural gas firing is the cleanest solution for brick kilns. Factory owners need to assess whether existing kilns can be retrofitted for natural gas combustion during factory planning.

Conclusion

When designing a fired brick production line, you need to calculate capacity for every link: raw material stock ≥ multiple days output; raw material processing ≥ 1.5 × daily output; aging chamber for 2–3 × daily output; extrusion workshop completes one daily output in 8–12 hours; green body storage for 1.5–2 × daily output; spare empty kiln cars ≥0.5 × daily output; drying chamber, firing section each match daily output; finished track ≥0.75 × daily output; unloading station ≥0.3 × daily output; finished yard for multiple days output.

Your brick plant’s real capacity and profit are determined by the weakest link in the whole systematic production chain.

Fired brick and tile raw material pretreatment including mixing, stirring and aging processes is the key to improving blank uniformity, molding effect and surface smoothness in modern brick and tile manufacturing. Reasonable raw material processing flows can maximize the utilization rate of brick and tile raw materials and optimize production efficiency.

Mixing and stirring operations focus on realizing the uniform distribution of raw material components and moisture. In the production of various clay bricks and fired tiles, different raw materials have different physical properties. Sufficient stirring can eliminate component stratification and ensure consistent molding performance of each batch of blanks. The auxiliary grinding and kneading process after stirring can crush large particle agglomerates, standardize raw material particle size, and make the raw material structure finer and more uniform, creating better conditions for subsequent extrusion molding.

Different from mechanical stirring, raw material aging is a physical and chemical comprehensive treatment process. During long-term aging storage, the water molecules in the mixed raw materials fully penetrate into the mineral particles, triggering hydration hydrolysis and ion exchange reactions. The generated colloidal cementitious substances greatly enhance the cohesiveness and ductility of brick raw materials. In addition, natural microbial activity and redox reactions in the aging environment soften hard raw material blocks, further improving the flowability and moldability of mud materials, so that the finally formed brick blanks have smooth surfaces and no cracks.

The selection of brick raw material processing equipment directly affects the effect of stirring and homogenization. Single-shaft and double-shaft mixers are suitable for conventional mass production, with simple structure and stable operation, meeting the basic mixing needs of proportioned raw materials. For high-end fired brick production with strict quality requirements, enterprises usually equip wet rolling mills. Its gravity rolling and kneading effect can complete secondary crushing and fine mixing of raw materials, effectively improving the adaptability of poor-quality raw materials.

As professional fine homogenization equipment, disc screens use high-strength scraping and shearing force to refine mud materials and remove impurities. The optional steam heating function realizes thermal pretreatment of raw materials and further improves plasticity. Purifiers focus on removing sundries in mud materials to ensure the purity of raw materials, while stirring extruders integrate multiple functions of mixing, kneading and plasticizing, which are essential equipment for standardized automatic brick production lines.

The raw material aging warehouse undertakes the dual functions of raw material storage and performance optimization in the production line. It can effectively balance the production rhythm and avoid production fluctuations caused by raw material performance differences. The industry has clear technical specifications for aging: the aging cycle must exceed 72 hours, and the environmental temperature must be maintained above 10°C. Constant temperature aging ensures sufficient physical and chemical reactions of raw materials and stable product quality in all seasons.

Automation is becoming increasingly important in modern brick manufacturing plants. As brick factories increase production capacity and introduce tunnel dryers, tunnel kilns, and automated handling systems, the process of moving and stacking green bricks has become an important part of overall production efficiency.

One of the key technologies used in this stage is the brick stacking robot.

A brick stacking robot is designed to automatically pick up freshly formed green bricks, transport them to a predetermined position, and arrange them according to a programmed stacking pattern. Instead of relying entirely on manual handling, the robotic system can coordinate with brick cutting, grouping, drying, and kiln-loading equipment.

Automatic green-brick handling systems are commonly positioned between forming/cutting equipment and drying or firing equipment. Their main functions include grouping, transferring, positioning, and stacking bricks according to the requirements of the production line.

What Is a Brick Stacking Robot?

A brick stacking robot is an industrial robotic system used to handle and stack bricks during the production process.

After bricks are extruded and cut, they are still relatively fragile. These freshly formed bricks are commonly called green bricks. Before entering the drying or firing process, they need to be arranged in a suitable pattern.

The robot performs several basic operations:

1. Pick up green bricks from the transfer or grouping system.
2. Move the bricks to the designated stacking position.
3. Rotate or adjust the bricks when necessary.
4. Release the bricks according to the programmed pattern.
5. Repeat the cycle until the required stack is completed.

The exact movement pattern depends on brick dimensions, production capacity, kiln or dryer configuration, and the required stacking method.

Why Is Green Brick Stacking Important?

The stacking stage may appear simple, but it can influence the efficiency of the entire brick production line.

Poorly arranged bricks can create problems during subsequent drying and firing. For example, inconsistent spacing may affect airflow, while unstable stacking can increase the possibility of collapse or damage.

For this reason, modern automated brick plants often focus on stacking consistency and positioning accuracy rather than simply increasing robot movement speed.

A properly designed automatic stacking system can help create repeatable brick arrangements and reduce dependence on manual stacking operations. Industry equipment suppliers commonly identify stacking pattern, green brick strength, robot reach, payload, and dryer/kiln layout as important factors when selecting a robotic stacking system.

How Does an Automatic Brick Stacking Robot Work?

A typical automatic brick stacking machine works through coordination between mechanical movement, sensors, control software, and the robot's gripping system.

Step 1: Green Brick Transfer

After extrusion and cutting, green bricks move through a conveyor or grouping system.

The bricks are organized into a predetermined arrangement before being picked up by the robot.

Step 2: Brick Gripping

The robot moves its gripper toward the green bricks.

The gripping mechanism must be designed according to the brick size, shape, weight, and strength. Different brick products may require different gripping configurations.

Step 3: Robotic Movement

The robotic arm lifts the bricks and moves them toward the target location.

Servo-driven movement can provide controlled positioning and repeatable operation. Industrial brick stacking systems may also use programmable positioning so that different stacking patterns can be implemented.

Step 4: Positioning and Stacking

The robot places the bricks at the programmed location.

Depending on the production design, the robot may change orientation between layers to create a stable stacking structure.

Step 5: Repeated Operation

The robot repeats the pick-and-place cycle until the required stack is completed.

The finished stack can then proceed to the drying or firing stage.

Key Features of the Brick Stacking Robot

The Brick Stacking Robot shown in the product design is built around several important components and functions.

Flexible Working Positions

The robot can be configured to operate at different positions according to the production line layout.

This is particularly useful when the available factory space, conveyor direction, dryer entrance, or kiln-car arrangement differs between projects.

Servo Motor Drive

A servo motor provides controlled movement and positioning.

For robotic brick handling, accurate movement is important because the gripper needs to repeatedly approach, lift, transport, and release bricks at predetermined positions.

RV Reducer

The RV reducer is an important mechanical transmission component used in robotic motion systems.

It helps transmit torque and supports controlled movement of the robot arm.

Customized Stacking

Different brick factories may produce different sizes and types of bricks.

Therefore, a stacking system should not be treated as a one-pattern solution. The gripper, movement path, stacking program, and final arrangement can be designed according to the actual brick production conditions.