Inovador no sector do cimento, autor em DARKO

As environmental regulations become stricter, dust control in quarries has become a key focus of the industry. Screening equipment and belt conveyors are essential machinery in quarries. However, the dust generated during their operation not only affects the production environment but also poses health risks to employees. Therefore, customized dust control engineering solutions are crucial.

Dust Control for Screening Equipment

Implementing sealed devices and dust collection hoods is a primary measure for dust control in screening equipment. This approach involves fully or partially enclosing the screening equipment and installing dust collection hoods to effectively reduce dust emissions. The design of these hoods must consider dust diffusion characteristics and airflow organization to ensure effective dust collection and minimize environmental pollution.

In addition, efficient dust removal equipment is indispensable. We recommend using bag-type pulse dust collectors. These devices achieve dust removal efficiency of over 99%, meeting the demands for high air volume processing. The selection of dust collectors should be tailored to the specific dust characteristics and processing needs.

Dust Control for Belt Conveyors

For dust control on transportadores de correia, bag-type pulse dust collectors are also the preferred choice. These collectors effectively manage dust generated during material transport, keeping the work environment clean. To enhance dust removal efficiency, we suggest placing dust extraction openings at the head, tail, and other dust-prone areas of the belt conveyor. The design of these openings must ensure they do not interfere with material transport, preventing secondary dust emissions.

System Control and Safety Measures

System control is also critical. Linking the dust collector's control system with the belt conveyor ensures that the dust collector operates automatically as needed. This integration improves system responsiveness. Additionally, installing pressure and temperature monitoring safety devices can further ensure the safe and stable operation of the dust collector under harsh conditions.

Site Survey and Customized Design

Before implementing dust control solutions, conduct a site survey to understand the specific layout and dust characteristics of the quarry. After thorough analysis, develop a targeted dust control design plan. This customized plan will ensure the appropriate model, specifications, quantity, and installation locations of the dust collectors, meeting production needs while reducing costs and enhancing space utilization.

Installation and Maintenance

During the installation phase, strictly follow the design plan and perform thorough testing before the dust control system goes live. Regular maintenance of the dust collectors is essential to ensure the cleanliness of the filter bags, which will extend the equipment's lifespan.

Conclusão

In summary, quarries can effectively improve their production environment and enhance employee safety through customized dust control solutions. The industry's development relies on recognizing and implementing environmental technologies. The future of the quarry industry urgently requires deeper exploration and technological innovation in environmental protection.

For more information or professional advice, please contactar-nos.

MAIS+

Guide to Rotary Valve Function and Maintenance

01/23

2025

01/23/2025

Working Principle of Rotary Unloading Valves

Rotary unloading valves play a crucial role in dust removal equipment for discharging ash, delivering air, and feeding other devices. Star-shaped unloaders are especially suitable for handling powdered and granular materials. Here are the key points of their working principle:

1.Pneumatic Output System: Rotary unloading valves are widely used in pneumatic output systems. Whether in pressure or vacuum output, star discharge valves provide a stable and continuous feed to the conveying pipe. This ensures stable gas and solid phases within the pipeline, promoting normal operation of the pneumatic transport system. Additionally, they effectively isolate the pressure between the upper and lower sections, serving a locking function. Therefore, star discharge valves are essential components in pneumatic transport systems.

2.Quantitative Discharge: As materials in the upper storage bin fall due to gravity and fill the gaps between the blades, the rotation of the blades discharges the materials below. This allows star-shaped unloaders to achieve quantitative and continuous discharging.

3.Wide Applications: Rotary unloading valves can serve as dischargers for storage bins, particularly in material collection systems. As advanced unloading devices, star-shaped unloaders play a vital role in dust removal systems. They find applications in industries such as environmental protection, metallurgy, chemicals, food, cement, road construction, and drying equipment.

4.High-Temperature Resistance: Standard rotary unloading valves can handle materials up to 280°C. Their bearings and impellers are isolated, preventing contact between powders and bearings. High-temperature unloaders can manage materials up to 500°C and utilize chain connections.

Structure of Rotary Unloading Valves

Rotary unloading valves typically consist of several parts:

1.Valve Body: The valve body is the main component, usually made from cast iron or stainless steel. The shape and layout of the internal passages determine the valve's applications and performance.

2.Rotor: The rotor is a key component, including the valve core, valve shaft, and valve. The core rotates within the body, altering the flow direction and opening or closing the pipeline.

3.Sealing Elements: Seals function between the rotor and valve body to prevent fluid leakage. Common materials for seals include rubber, PTFE, and metal.

4.Drive Mechanism: This mechanism operates the rotor and may include handwheels, electric motors, or pneumatic drives.

5.Accessories: Accessories like safety valves, exhaust valves, and locking devices enhance the safety and convenience of rotary valves.

Maintenance Methods for Rotary Unloading Valves

In a factory setting, equipment may encounter problems during operation. As a widely used product, unloading devices can experience various issues. Here are some maintenance and repair tips:

1.Regularly Check Lubrication: Unloading devices come filled with lubricants and grease from the factory. During operation, regularly inspect the lubrication oil, especially in high-temperature or dusty environments. Reduce the oil change interval to prevent damage.

2.Address Air and Dust Leakage: If air or dust leaks occur along the axis during operation, tighten the screws on the pressure cover. Alternatively, replace the packing and re-secure the cover.

3.Follow Disassembly Procedures: The internal structures of various models are similar, and the disassembly and assembly processes are generally the same. During transport, keep the device stable to avoid impacts that could damage the casing or motor.

4.Self-Diagnose Faults: When issues arise due to inadequate maintenance, users should learn to self-diagnose faults to enhance efficiency.

- Incorrect usage and imprecise operation can damage the motor. Always follow proper usage guidelines.
- Periodically check the cleaning control system to ensure correct cleaning cycles. Inspect the pressure switch and clear any blockages in the pressure measuring points.
- Regularly measure process parameters such as gas volume, temperature, and concentration. Investigate and address any anomalies promptly.
- When the unloading valve stops, continue operating the unloading valve and exhaust fan for a while to eliminate moisture and dust from the equipment. Manual cleaning may be necessary to prevent moisture from affecting the filter bags.

By following these maintenance practices, users can extend the lifespan of rotary unloading valves and ensure their reliable performance in various industrial applications.

For more information or support, please feel free to contactar-nos. We are ready to provide you with professional advice and solutions.

MAIS+

Considerations for Cement Cooling Processes

01/20

2025

01/20/2025

Em cimento production, the cooling process plays a crucial role in ensuring the quality and performance of cement. The cement cooling process mainly consists of two methods: online cooling and post-storage cooling. The latter method is particularly suitable for processes that require strict temperature control due to its large cooling range and controllable temperature. To ensure effective cooling and the normal operation of equipment, it is essential to pay attention to several key issues during application.

1. Local Cooling Issues

When using a single silo cooling process, cement exits the silo, enters the cooler, and then returns to the same silo via an elevator. This method may lead to a situation where the cooler's discharge temperature meets the requirements, but the temperature of the material released from the silo remains high and does not meet standards. The root cause of this phenomenon lies in the formation of a material flow channel between the silo's entrance and exit. Since the material flows continuously in and out, other materials in the silo cannot enter this channel, resulting in rapid cooling of the material in the channel while the rest remains inadequately cooled.

To solve this problem, I recommend using a dual-silo process. Specifically, the material from one silo passes through the cooler and enters another silo. If the temperature still does not meet the requirements, the material can be released from the second silo and returned to the first silo for a cyclical operation. This method effectively improves cooling efficiency and ensures that the cement temperature meets the standards.

2. Cement Caking Issues

During storage, temperature differences often cause cement to cake on the walls of the silo, especially in steel silos. As the cement level decreases, some of these caked materials may fall off and enter the cooler along with the cement. The accumulation of these caked materials can affect the moving parts inside the cooler and may lead to mechanical failures.

To address this issue, I suggest installing equipment to remove cement caking before the cooler or setting up inspection ports at appropriate locations on the cooler. This allows for regular cleaning of the caked cement, ensuring the normal operation of the equipment.

3. Expansion Box Issues

The expansion box phenomenon occurs when cement fills the cooler's housing. Mechanical action causes the cement to expand, leading to deformation of the cooler's housing and potentially causing blockages or damage to mechanical parts. This situation primarily arises when the discharge amount from the silo exceeds the processing capacity of the cooler or elevator.

To resolve this issue, I recommend installing flow-stabilizing feeding equipment under the silo. This ensures that the discharge amount does not exceed the processing capacity of the cooler and elevator, thereby avoiding overload situations.

Conclusão

The external circulation cooling process of cement silos plays a vital role in cement production. Through proper process design and equipment maintenance, we can effectively enhance cooling efficiency and ensure cement quality. I hope the above suggestions provide valuable insights for industry professionals and contribute to the smooth operation of cement production.

If you would like to learn more about the external circulation cooling process of cement silos or have any questions, please feel free to contactar-nos. We look forward to providing you with professional support and services!

MAIS+

Quality Control in Cement Grinding Process

01/16

2025

01/16/2025

S Cement Plant is a modern dry-process fábrica de cimento. It uses advanced grinding equipment and technology. The plant employs a CKP vertical mill and a ball mill in a closed circuit system. The CKP mill is CKP-170, and the moinho de bolas has dual chambers with specifications of φ3.9m×12m. It features a cyclone separator. The system's capacity is 115t/h×2.

Clinker and gypsum go through a crusher and break down to particles of ≤40mm, which make up over 95%. They are fed into the CKP mill. The material from the CKP mill contains over 95% of particles ≤10mm. About 10% of this material returns to the CKP mill, while roughly 90% moves to the ball mill along with the separator's return. The ball mill's output combines with fly ash and enters the separator. The separator achieves an efficiency of about 60%, with a circulation load rate of approximately 260%. Most of the cement produced is P.O 42.5R, with a small amount of P.II 42.5R. The average power consumption for both types is 39 kWh/t, using a grinding aid that accounts for 0.02% to 0.03% of the cement weight.

Quality Control Methods and Experience in the Cement Grinding Process

1. Quality Control Methods

The plant uses imported German negative pressure sieves to measure the residue at 15μm, 20μm, 32μm, 45μm, and 63μm based on Japanese methods. The German sieves have a sieve size with an inner diameter of 70mm and a sample weight of 1g. This design allows for a larger airflow during operation, preventing clogging of the sieve holes. The device can complete the measurement of 32μm residue in 8-10 minutes and 45μm residue in 4-6 minutes. It has high machining precision, low failure rates, easy operation, short measurement time, and stable, accurate results, making it suitable for routine production control.

Many domestic cement companies use laser particle size analyzers to measure the particle size distribution of cement. This plant conducted parallel tests using both the negative pressure sieve and the laser analyzer on the same sample. The results showed that the laser analyzer yielded consistent results with the negative pressure sieve for particles over 10μm. However, for particles under 10μm, the laser analyzer's results were slightly higher. This difference occurs because very fine particles tend to agglomerate due to van der Waals forces, making them difficult to disperse in negative pressure sieving. While the laser analyzer is suitable for periodic checks, its complexity, longer operation time, and higher failure rates make it unsuitable for routine quality control.

2. Quality Control Experience

2.1 Fineness

The plant uses the 32μm residue as a routine control basis for the grinding process. When the 32μm residue is within the target control range, the 80μm residue is stable at 0.2% to 0.4%. However, due to equipment failure, the 32μm residue occasionally fluctuated from the target of 16% to 20%. Testing this batch of cement showed a 28-day compressive strength drop of about 4MPa, indicating that the 80μm residue does not effectively reflect the grinding condition. Therefore, using 32μm or 45μm residue as quality control indicators is appropriate.

2.2 Specific Surface Area

Although the plant measures the specific surface area every 4 hours, these measurements serve only as reference points and do not guide routine control. Statistical analysis reveals no strong correlation between strength and specific surface area. Thus, using specific surface area as a control basis is too rough.

2.3 Particle Distribution

The particle size distribution of cement is closely related to its physical properties, especially strength. Experience shows that using 32μm or 45μm residue effectively reflects particle distribution and should be included in routine control.

2.4 Grinding Aids

The plant adds a grinding aid that accounts for 0.02% to 0.03% of the cement weight during grinding. This addition proves effective. There was a brief interruption of the grinding aid, and although the 32μm residue remained within control limits, the particle distribution changed significantly, leading to a noticeable drop in strength.

Conclusão

1.The cement grinding equipment and technology are suitable. The cement's particle distribution is close to the ideal, resulting in improved strength.

2.Particle distribution significantly affects cement's physical properties, particularly strength. Using 32μm or 45μm residue as quality control indicators is appropriate.

3.The combination of vertical and ball mills is an effective cement grinding solution, producing high-quality products with reasonable power consumption.

4.Proper use of grinding aids improves the cement's particle distribution and reduces the quantity of particles smaller than 3μm.

5.Compared to laser particle size analyzers, negative pressure sieves are more suitable for routine quality control.

If you have any questions or needs regarding cement grinding, please feel free to contactar-nos. We look forward to collaborating with you to advance the development and progress of the cement industry!

MAIS+

Dust Collector Explosion-Proof Design

01/14

2025

01/14/2025

Dust explosions occur when dust particles suspended in the air come into contact with oxygen and undergo a rapid oxidation reaction under specific conditions. This reaction releases a large amount of heat, resulting in high temperatures and pressures, which can be extremely dangerous.

Conditions for Dust Explosion

Four key conditions must be met for a dust explosion to occur:

1.Combustible Particles: The dust particles must be small enough and distributed in a cloud-like state at a sufficient concentration.

2.Oxidizing Agent: There must be enough oxygen to support combustion.

3.Ignition Source: There must be a sufficient energy ignition source.

4.Enclosed Space: A closed space must exist to support the explosion.

Anti-Explosion Measures

The goal of anti-explosion measures is to extinguish combustible materials within the equipment at the initial stage. This action prevents excessive explosion pressures. A successful suppression system can activate when the explosion pressure reaches 10 kPa, ensuring that the maximum pressure inside the equipment remains below 100 kPa. If an explosion occurs, explosion venting is the most reliable and economical method to protect bag filters. The most common form of explosion venting is through explosion venting devices.

1. Explosion Prevention Measures

Effective measures to prevent dust explosions primarily involve using a good dust collection system to control and prevent dust accumulation. Specific measures include:

Preventing Dust Accumulation in Pipes: Ensure that there is no dust buildup in the pipes.

Strictly Controlling Ignition Sources: Avoid open flames, hot surfaces, welding, cutting, and electrical sparks.

Using Inert Gases: Reduce oxygen concentration to prevent explosions. Although effective, this method may be difficult to implement in some situations and requires significant investment.

2. Structural Design Measures

Special structural designs can help prevent combustible dust accumulation inside the dust collector. All beams and partitions should have dust covers. The cover angle should be less than 70°, and the hopper's slope should be greater than 70°. To eliminate dust accumulation due to small angles between hopper walls, adjacent side panels should be welded with material slides. Additionally, designers should consider adding heating elements to prevent blockages caused by improper operation or high humidity. Each hopper should also have wall vibrators or air cannons to prevent dust buildup.

Dust collectors can have anywhere from 1 to 12 hoppers, which may lead to uneven airflow. To address airflow distribution issues, consider the following solutions:

1.Add baffles to the airflow duct.

2.Use adjustable valves between the lifting valve rod and valve plate to accommodate changes in the working environment.

3.Install airflow regulation valves in the inlet branch to adjust airflow in each chamber, keeping the difference within 5%.

3. Equipment Grounding and Explosion-Proof Components

Due to safety requirements, explosion-proof dust collectors often operate outdoors. Grounding and lightning protection become essential measures. However, dust collectors typically do not have lightning rods.

Choosing explosion-proof components is crucial in explosion prevention. Dust entering electrical load components can induce explosion risks. During operation, electrical load components may generate electric sparks due to current transmission. This can easily trigger an explosion in the presence of dust. Therefore, all electrical load components must be explosion-proof. This measure eliminates potential explosion risks and ensures safe operation. For instance, the pulse valves and lifting valves of pulse dust collectors must be explosion-proof.

4. Static Electricity Protection Measures

Within the dust collector, high concentrations of dust can generate static electricity through friction. This static charge can lead to sparks and potential fires. To mitigate static hazards, use conductive materials in filter bags. For example, embed conductive metal wires or carbon fibers in polyester needle felt to discharge accumulated static.

5. Detection and Fire Prevention Measures

To prevent incidents before they occur, implement necessary fire prevention measures in the dust collection system:

Firefighting Facilities: Common options include water, CO2, and inert extinguishing agents. Cement plants typically use CO2, while steel mills may employ nitrogen.

Temperature Detection: Install thermometers at the inlet of the dust collector to monitor temperature changes. If the temperature rises abnormally, the system should trigger an alarm.

CO Detection: In large dust collection systems, it may be challenging to monitor temperature changes across all locations. Therefore, install a CO detection device at the dust collector outlet or hoppers to monitor for combustion signs.

6. Explosion Venting Devices

Use explosion venting membranes, rupture discs, and vent doors to ensure timely pressure release during an explosion. This action prevents air from entering and fueling further combustion.

Calculation of Explosion Venting Area

Calculating the explosion venting area is crucial. For dust collectors handling high concentrations of explosive dust, an insufficient venting area will not meet requirements, while an excessive area can lead to waste. Typically, the ratio of venting area to dust collector volume should remain between 1:5 and 1:50, depending on the dust's explosion index.

In design, set the venting pressure to half of the bag chamber design pressure, typically between 5 and 7.5 kPa, with a maximum of 10 kPa. When the internal pressure of the dust collector reaches this value, the venting device should activate to release pressure.

Moreover, to ensure rapid pressure release, ample space is necessary. Position the venting outlet appropriately and use pipes to direct exhaust to the outdoors for safe venting.

Selection of Accessories

1. Selection of Anti-Static Filter Materials

During operation, filter bags can generate and accumulate static electricity. This accumulation can attract dust, leading to a layer of dust that may reach 0.5 to 2 mm thick. The discharge of static electricity can create sparks, posing a risk of dust explosions. Thus, to mitigate static hazards, ensure the filter material can release static charges through the grounded dust collector body. Incorporate conductive fibers into the filter material to enhance conductivity. These fibers can be metallic or modified synthetic fibers.

Stainless steel metal fibers (4-20 mm) offer excellent conductivity and can easily blend with other fibers. They exhibit good flexibility, mechanical strength, chemical resistance, and high-temperature tolerance, making them suitable for anti-static filter materials.

2. Explosion-Proof Pulse Valves

For pulse bag dust collectors in explosive environments, select explosion-proof pulse valves. There are two main types: one enhances the sealing of the solenoid valve, and the other integrates the solenoid pilot valve within an explosion-proof solenoid valve assembly, connecting it with air tubes.

3. Fire Extinguishing Devices

Dust collectors should include temperature warning systems and automatic fire extinguishing devices. When CO2 concentration in the air reaches 30%-40%, it can suffocate combustible materials. At 40%-50%, it can suppress gasoline vapors and other gas explosions. The CO2 automatic extinguishing device should have a fixed CO2 supply source, releasing CO2 extinguishing agents through connected pipes with nozzles.

Each hopper should also have a nitrogen protection device to prevent smoldering. This device consists of a resistance thermometer, control system, solenoid valve, and nitrogen injection pipe (1.5 in/DN32). When the temperature in the hopper exceeds the set alarm temperature (adjustable between 100-200°C), the solenoid valve opens automatically to inject nitrogen. The injection time can be adjusted from 0 to 30 minutes, controlled by a PLC.

By implementing the above preventive and safety measures, we can effectively reduce the risk of dust explosions and protect both equipment and personnel. Proper dust management in industrial operations contributes to a safer working environment.

For more information or to learn about our products, please contactar-nos. Darko is committed to providing high-quality explosion-proof dust collection solutions to ensure your industrial safety.

MAIS+

Solutions for Belt Misalignment in Belt Conveyors

01/13

2025

01/13/2025

Belt misalignment is a common and challenging problem in the operation of transportadores de correia. The root cause of misalignment lies in the net external forces acting on the belt in the width direction, which is not zero, or uneven tensile stress perpendicular to the belt width. This imbalance causes the reaction force from rollers or drums to exert a sideways force on the belt, leading to misalignment. This article analyzes the causes of belt misalignment and provides effective corrective measures.

Causes of Belt Misalignment

1. Misalignment of Centers

The head, tail, and middle frames may not align properly. This misalignment often occurs due to improper installation, causing the belt's longitudinal centerline to be non-perpendicular to the drum axis, affecting operation.

2. Incorrect Roller Position

All rollers must be installed perpendicular to the belt centerline and parallel to the horizontal plane. If this requirement is not met, the belt will shift to one side.

3. Improper Belt Joint

Whether using mechanical or vulcanized joints, any irregularities in the joint can lead to uneven tension on both sides, causing misalignment during operation.

4. Misaligned Roller Frame

The centerline of the roller group must align with the centerline of the machine frame. The allowable error is no more than 3.0 mm. If the roller frame is improperly installed or bolts are loose, the belt may misalign.

5. Belt Damage

If the degree of damage is inconsistent on both sides of the belt, it may cause uneven stretching and result in misalignment.

6. Improper Discharge Point

Uneven material discharge can lead to uneven force distribution on the belt, causing it to misalign. If the discharge point is off-center, it should be adjusted promptly.

7. Impact from Material Drop

When material falls onto the belt, its weight and inertia can cause the belt to shift.

8. Accumulated Material

Sticky materials can accumulate on rollers or drums, leading to uneven tension and causing misalignment.

9. Incorrect Roller Angle

If the roller installation angle is not accurate, it can cause the belt to shift in the carrying section.

10. Belt Quality Issues

If the density of the belt is uneven, this can lead to uneven tension and result in misalignment.

11. Tensioning Device Issues

Improper installation or adjustment of the tensioning device can lead to uneven tension and cause misalignment.

12. Aging from Long-Term Use

Over time, belts can loosen, increasing the risk of misalignment.

13. Frame Inclination

If the frame is tilted, it can exert lateral force on the belt.

14. Equipment Vibration

Severe vibrations during operation, particularly radial movement of rollers, can cause the belt to misalign.

15. Small Curvature Radius

If the curvature radius of a concave section is too small, the belt may lift during startup.

Corrective Measures for Belt Misalignment

To address the above causes, the following measures can be implemented:

Align the Head, Tail, and Middle Frames: Ensure all three components are aligned on the same centerline.

Correct Roller Position: Ensure the roller axis is perpendicular to the belt and parallel to the horizontal plane.

Adjust Belt Joints: Remove any improperly aligned joints and ensure they are straight.

Realign Roller Frames: Move the roller frame on the misaligned side and recalibrate as necessary.

Enhance Maintenance: Regularly inspect the belt and promptly repair or replace any damaged sections.

Adjust Discharge Point: Ensure the discharge point is centered on the belt.

Design Appropriate Material Guides: Avoid direct drops of large objects and install buffer rollers at the discharge point.

Clear Accumulated Material: Keep roller and drum surfaces clean and maintain the operation of cleaning devices.

Adjust Roller Group Position: Modify the installation holes based on the direction of misalignment.

Choose Reputable Manufacturers: Ensure quality equipment and good after-sales service.

Install Tensioning Devices Properly: Make sure the centerline is perpendicular to the roller axis and follow installation requirements.

Realizar inspecções regulares: Replace aging or deformed belts promptly.

Correct Frame Inclination: Reinstall the frame to ensure it is level.

Identify and Address Vibration Issues: Resolve any sources of equipment vibration.

Add Pressure Rollers: Install pressure rollers in concave sections to prevent the belt from lifting.

In the operation of belt conveyors, it is essential to monitor belt misalignment closely. Timely identification of the causes and implementation of appropriate measures are key to maintaining efficient and stable operation. By following these corrective actions, you can effectively reduce the risks associated with misalignment and enhance production efficiency.For further inquiries or assistance, please feel free to contactar-nos! We are here to help and support you.

MAIS+

Using Cartridge Collectors in Steel Industries

01/10

2025

01/10/2025

1. Working Principle and Characteristics of Cartridge Dust Collectors

1.1 Working Principle

Cartridge dust collectors use cartridges as the filtering element and employ pulse jet technology for dust removal. The working principle involves dusty air being sucked into the housing through the dust hood, ducts, and air inlet. As the air flow suddenly expands and interacts with the air distribution plate, larger dust particles fall directly into the dust hopper due to gravity and inertia. Smaller and lighter particles pass through the cartridge, where they are captured by the filter material through Brownian diffusion and sieving effects. After backflushing, the dust falls into the dust bin for recycling, while clean air is discharged through the exhaust pipe with the help of a fan.

1.2 Advantages

1.High Dust Removal Efficiency: The cartridges use imported polyester fibers as filter media. They feature a layer of ultra-thin sub-micron fibers that effectively block most sub-micron dust particles, achieving a filtration efficiency of up to 99.99%, meeting ultra-low emission standards.

2.Low Operating Resistance: Thanks to the large filtration area and low filtration velocity, the operating resistance typically does not exceed 1000 Pa. This reduces the operational load and costs of the dust collection system.

3.Compact Structure: The design of the cartridges occupies minimal space, making installation and replacement easier. Cartridges are generally shorter than bag filters, simplifying construction and maintenance.

4.Long Service Life: The cartridges use durable polyester fibers, allowing a lifespan of over three years. This reduces the frequency of replacements and maintenance efforts.

5.Reusable: Polyester cartridges and membrane-covered cartridges can usually be washed with water and reused, lowering procurement costs.

1.3 Disadvantages

1.Poor Suitability for Moist, Sticky Waste Gas: In humid environments, cartridges can become blocked, requiring downtime for replacements, which affects production efficiency.

2.Higher Costs: The price of cartridges is over five times that of standard bag filters, leading to higher overall construction costs.

3.High Requirements for Airflow Uniformity: Uneven airflow can cause certain cartridges to experience excessive filtration velocity, which shortens their lifespan.

4.High Manufacturing Quality Requirements: The folded structure and quality of the cartridge seals directly affect operational performance, necessitating strict quality control.

2. Characteristics of Smoke and Dust in Various Steel Production Processes

Steel enterprises produce various types of smoke and dust, which differ significantly across processes:

2.1 Sintering Raw Material Area

Due to transportation issues, both domestic and foreign ores generally have a moisture content above 6%. The use of enclosed storage sheds and spray dust suppression further exacerbates dust emissions.

2.2 Sintered Product and Ore Bin Area

1.Sintered products generate dust particles ranging from 0.8 to 61.0 μm during transport, with moisture content below 1%.

2.Blast furnaces commonly use heated grinding techniques, with particles below 200 mesh comprising 76% to 84%, and moisture content also below 1%.

3.During coke transportation, the moisture content is below 1% for dry quenching processes, while wet quenching processes often exceed 10%.

2.3 Converter Steelmaking Area

1.Fluxes used in converters typically have a moisture content of 1.0% to 1.5%.

2.Dust generated during the steelmaking process has over 98% of particles larger than 5 μm, with low temperatures.

3.The moisture content of dust from converter slag handling often exceeds 10%.

2.4 Rolling Steel Production Area

Wet gas emissions during rolling processes usually exceed 10% humidity, primarily due to water cooling.

2.5 Coking Production Area

1.Coal dust generated during the coking preparation area often has a moisture content above 6%, with over 99% of particles larger than 2 μm.

2.The dust particle size during coal pushing generally ranges from 3.3 to 4.7 μm, with waste gas humidity between 1% and 5%.

2.6 Flux Production Area

During the transport of limestone and finished lime, over 95% of dust particles exceed 10 μm, with moisture content below 1%.

3. Recommendations for Using Cartridge Dust Collectors in Steel Enterprises

1.Avoid Collecting High-Humidity Waste Gas: This includes waste gas from iron ore in the sintering preparation stage and from wet coking processes.

2.Use Caution with Sticky Waste Gas: This applies to dust generated during lime transport and in the coking process.

3.Optimize Inlet Design: Lower the inlet airspeed of the cartridge dust collector and improve internal airflow distribution to ensure uniform flow among cartridges.

4.Ensure Uniform Backflushing Airflow: The length of the backflushing nozzle should be maximized to maintain even airflow distribution.

5.Strictly Control Cartridge Quality: Ensure that the technical parameters of folded cartridges meet relevant standards. Inspect the quality of the membrane and uniformity of folds, and verify the manufacturing process of the cartridge seals.

In conclusion, cartridge dust collectors hold significant promise for use in steel enterprises. However, optimizing design and usage strategies based on specific operating conditions is essential to enhance dust removal efficiency and cost-effectiveness. Choose Darko’s cartridge dust collectors for outstanding performance and reliable solutions.

For more information about our products or to seek professional advice, please feel free to contactar-nos!

MAIS+

Cement Mill Buildup Phenomenon and Its Solutions

01/09

2025

01/09/2025

Introdução

Cement is an essential construction material. Its quality directly affects the safety and durability of buildings. Therefore, cementmsdjfghjkl; production requires strict adherence to standards. However, during production, buildup phenomena often occur, leading to coarser product fineness and significant changes in chemical composition. At the beginning of buildup, the content of difficult-to-grind components decreases. As buildup gradually resolves, these components’ proportion increases, directly impacting product quality. Effective management and control of the cement-making process are crucial for ensuring stable production and improving cimento quality.

Signs of Buildup

"Buildup," also known as "full mill" or "blind mill," occurs frequently during ball mill operations. Signs of buildup include:

The grinding noise shifts from clear to dull, and the discharge amount decreases.
The pressure in the inlet and outlet of the drying mill increases.
The grinding noise may disappear, and the main motor current drops to about 70% of normal, with a significant reduction in discharge.
In severe cases, material may backflow, and no discharge occurs from the outlet.

When inspecting the mill, you may find:

A thick layer of material on the mill lining, possibly up to 50mm.
A thick layer of material covering steel balls and segments.
Severe clogging of the mill's partition screen.
About 90% of the effective space in the mill occupied by grinding media and material.

Causes of Buildup

Buildup primarily results from an imbalance between the mill's feed and discharge, leading to excessive material accumulation in the mill. Specific causes include:

1.Excessive Feed: When the feed rate significantly exceeds the mill’s grinding capacity, material accumulates, causing buildup.

2.Changes in Material Size: If the particle size of the incoming material increases or its grindability decreases, and the feed rate is not adjusted promptly, buildup occurs.

3.High Moisture Content: Excess moisture in incoming materials and poor ventilation can cause wet material to stick to the grinding media and lining, reducing grinding efficiency.

4.Clogged Partition Screens: Fragments of iron and debris can block the partition screens.

5.Closed Circuit System Issues: A decrease in the efficiency of the classifier leads to excessive recirculation of material.

6.Uneven Grinding Media Filling: Significant differences in filling rates between the first and second compartments can lead to issues.

7.Damaged Partition Screens: Localized breakage or perforation of partition screens can cause media to move between compartments.

Once buildup occurs, control parameters will show a sharp drop in the mill's main motor current. The discharge current from the outlet will approach idle levels, indicating severe buildup.

Solutions for Buildup

Upon detecting buildup, you should promptly identify the cause and take action. Common solutions include:

1.Reduce or Stop Feeding: Enhance ventilation within the mill to operate with minimal or no feed, generating more heat.

2.Increase Inlet Heat: In drying mills, increase the heat at the inlet to facilitate rapid evaporation of moisture.

3.Add Grinding Aids: Add dry coal or limestone to raw material mills, or dry slag to cement mills. Once the grinding noise approaches normal, gradually resume feeding.

4.Gradually Open Exhaust: When addressing buildup in the second compartment, close the exhaust fan damper. Allow material to drop before gradually reopening it to avoid sudden load changes.

In cases of severe buildup, you can use reverse grinding methods to clear the chamber of balls and material. Thoroughly clean the lining and partition screens to restore normal operation.

Conclusão

The factors causing buildup in moinhos de cimento are multifaceted. Identifying the primary causes and adhering to the principle of "prevention first, elimination second" can help control and eliminate buildup effectively. This approach will lead to high-quality, high-yield, low-consumption, and safe cement production.

For more information about our products and services, please feel free to contactar-nos.

MAIS+

Effective Measures to Address Arching Phenomenon in Cement Silos

01/07

2025

01/07/2025

As awareness of environmental protection and energy conservation grows, bulk cement, which is easy to transport and has low pollution with accurate measurement, has become one of the main building materials. However, the functions of silos de cimento have evolved from simple storage to include dust removal, arch breaking, and measurement. The arching phenomenon in cement silos is a common and challenging issue that needs urgent attention.

The Arching Phenomenon and Its Impact

The arching phenomenon occurs when cement forms a dome-shaped cavity at the outlet of the silo, preventing it from falling. This issue hinders the transportation of cement, disrupts the normal operation of the batching plant, and causes uneven feeding, which directly affects the accuracy of weighing and batching.

Causes of Arching

Several factors contribute to arching:

Internal Friction and Cohesion of Cement
These forces create shear stress and result in a certain overall strength that hinders particle movement and reduces flowability.
External Friction of Cement
This refers to the friction between cement and the walls of the silo. It depends on the roughness of the walls and the angle of the conical section. Greater roughness and smaller angles increase external friction, making arching more likely.
Temperature of External Air
Temperature and humidity affect the cohesion of cement, reducing its flowability and increasing the risk of arching.
Hydraulics at the Silo Outlet
A smaller hydraulic radius at the outlet reduces the core flow area within the silo, making arching more likely.

Preventive Measures

To effectively prevent arching in cement silos, we should take the following measures during design, construction, and operation:

1. Side Discharge Design

Using a side discharge design is an effective way to prevent arching. Adding more discharge points or using inclined discharge can reduce vertical pressure and help break the arch. Discharge points should be compatible with the transportation equipment. Too many discharge points increase costs and complicate operations.

2. Reduce Internal Friction

Design the silo with smooth internal walls to create optimal sliding conditions. While most silos use reinforced concrete, consider lining the funnel section with steel plates or applying coatings to reduce internal friction.

3. Control Moisture

Cement has high moisture absorption. Therefore, controlling moisture intrusion is crucial. Reduce moisture brought in by the cement itself, prevent rainwater infiltration, and limit moisture from pneumatic conveying systems.

4. Dehumidification and Drying of Compressed Air

During compression, moisture in the air condenses. Implement strict dehumidification measures to ensure that compressed air remains dry during storage, transport, and use. This prevents cement from clumping and arching.

5. Increase the Angle of the Conical Section

Set the angle of the conical section to be greater than the external friction angle of cement (approximately 32°) to reduce external friction. A typical range for this angle is between 55° and 65°.

6. Increase the Diameter of the Silo Outlet

Widening the outlet diameter helps improve the flowability of cement and reduces the occurrence of arching.

Conclusão

By applying these measures, we can effectively prevent arching in cement silos, enhance cement transportation efficiency, and ensure a stable supply of building materials. Continuous optimization of design and operational processes is essential to meet the growing market demand.

If you need high-quality cement silos or want to learn more, please contactar-nos. Darko will provide you with professional solutions and excellent service!

MAIS+

Electromagnetic Vibrating Feeder: Applications and Maintenance

01/06

2025

01/06/2025

O electromagnetic vibrating feeder is widely used in various industries, including mining, metallurgy, coal, building materials, light industry, electric power, machinery, and food. It functions to transport bulk, granular, and powdered materials from storage bins or hoppers to receiving devices in a uniform, continuous, or precise manner.

Caraterísticas principais

1. Intelligent Electrical Control

The feeder uses a half-wave rectification circuit, allowing for stepless adjustment of the feeding amount. This feature supports automatic control in production processes, promoting automation.

2. Simple Structural Design

The device contains no rotating parts and requires no lubrication. Its simple structure makes maintenance easy, reducing operational complexity.

3. Low Wear Operation

The materials move in a micro-throwing motion within the feeder, resulting in minimal wear on the trough. This design extends the equipment's lifespan.

4. High-Temperature and Corrosion Resistance

The trough is made of alloy steel plates, enabling it to handle materials that are high-temperature, highly abrasive, or corrosive.

Maintenance Points

1.Regular Inspections: Frequently check the amplitude of the trough and the coil current. Pay attention to any unusual noises. If you notice a sudden increase in noise or any impact sounds, analyze the cause immediately and stop the machine.

2.Maintain Balanced Air Gap: Keep the air gap between the core and the armature balanced. Regularly inspect bolts for looseness and ensure the gap is within normal limits. If the spring bolt is loose or the spring is broken, address these issues promptly.

3.Check the Lifting Device: Regularly inspect the lifting device for looseness. A loose lifting device can cause imbalance at the corners of the feeder, affecting the feeding quality. Tighten it immediately if necessary.

4.Clean the Sealing Cover: Ensure the sealing cover of the vibrator is intact to prevent dust from entering and clogging the gaps between the springs. Regularly clean any dust buildup on the sealing cover.

Common Fault Analysis

1. Machine Does Not Vibrate After Power On

Cause: Blown fuse or shorted coil wires.
Solution: Replace the fuse and check the resistance to repair any breaks.

2. Material Transport Direction Is Off

Cause: The centerline of the trough and the line of excitation force are not in the same vertical plane.
Solution: Adjust them to be in the same vertical plane.

3. Weak Vibration

Cause: The thyristor is damaged or the air gap is blocked.
Solution: Replace the thyristor and remove any blockages.

4. Loud and Irregular Noise

Cause: Broken spring or loose connection bolts.
Solution: Replace the spring and tighten the bolts.

5. Torsional Vibration Occurs

Cause: The line of excitation force is not aligned with the center of the trough.
Solution: Adjust the excitation force line to pass through the center of the trough.

6. Current Fluctuates

Cause: Damaged coil or poor contact.
Solution: Inspect the coil for shorts or loose connections in the control box.

7. Normal Operation with High Current

Cause: The air gap may be too large.
Solution: Adjust the air gap to about 2 mm.

8. Insufficient Feeding

Cause: The trough's vibration does not meet the required amplitude.
Solution: Check if the hopper load directly compresses the feeder trough. Adjust the air gap and ensure proper spring tension.

9. Rectifier Failure During Operation

Cause: Short-circuited coil or leakage (grounding).
Solution: Replace the thyristor and coil, and fix the leakage issue.

10. Excessive Vibration of the Foundation

Cause: The stiffness of the isolation springs may be too high.
Solution: Reduce the stiffness of the isolation springs.

Conclusão

The electromagnetic vibrating feeder offers a simple structure, low noise, and lightweight design. It operates easily and consumes little power. It supports automation in production processes with stepless adjustment capabilities. The feeder can frequently start and operate continuously under rated voltage and amplitude conditions, making it widely applicable across various industries. Regular maintenance and inspections will effectively extend the equipment's lifespan and ensure efficient and stable production.

If you have any questions or need further support, please feel free to contactar-nos. We look forward to providing you with professional service and solutions!

MAIS+

LS Screw Conveyor: Efficient Material Handling Solution

01/03

2025

01/03/2025

O LS screw conveyor is widely used for material transport. The name "LS" stands for "screw" and "horizontal" transport. This equipment comes in various diameters, including 100, 160, 200, 250, 315, 400, 500, 630, 800, 1000, and 1250 mm. The maximum length of a single unit can reach 35 meters (30 meters for LS1000 and LS1250). It operates effectively in temperatures ranging from -20℃ to 50℃ and can transport materials at angles less than 20° and temperatures not exceeding 200℃.

Vantagens

Estrutura simples: The design is compact, and the cross-section is small, leading to lower manufacturing costs.
High Flexibility: It allows for intermediate loading and unloading at multiple locations.
Safe Operation: The design ensures ease of use and safety.
Boa vedação: The cover design effectively isolates materials from the outside, preventing leaks.

Desvantagens

High Power Consumption: Moving materials requires overcoming friction between materials and the casing or screw.
Material Crushing: The screw action may crush materials during transport.
Severe Wear: The screw and casing wear out easily over time.

Due to these pros and cons, the LS screw conveyor suits various powdery, granular, and small block materials, such as coal powder, flour, cimento, sand, grãos, briquettes, and stones. However, it is not suitable for perishable, sticky, or easily clumping materials since they may stick to the screw and cause operational issues.

Additionally, the effective flow cross-section is small, making it unsuitable for large block materials. To ensure normal operation, maintain a uniform feed to avoid material blockages and overloads.

Installation Requirements

The installation of the screw conveyor must meet the following technical conditions to ensure proper operation:

Foundation Requirements: Complete the foundation at least 20 days before installation for stability.
Parts Inventory: Check all components before installation to ensure nothing is missing and clean them.
Symmetrical Installation: Align the casing and end frames symmetrically in the vertical plane.
Horizontal Alignment: Keep the centerline of the casing consistent in the horizontal plane.
Smooth Connections: Ensure there are no significant height differences at the joint surfaces of adjacent casings.
Stable Base: Secure the base after installation and tighten the corner bolts.
Bearing Support: Ensure the intermediate suspension bearing supports the connecting shaft properly to avoid bending or suspension.
Tight Connections: Tighten all connection screws to a reliable degree.
Lubrication Check: Check the oil level after installation to ensure it is sufficient.
No-Load Testing: Conduct at least 4 hours of no-load testing after installation to observe smooth operation and check for leaks, overheating, or looseness.

Address any issues immediately to ensure proper function.

Operation and Maintenance

The LS screw conveyor transports powdery and small block materials. It often operates in harsh environments, making proper operation and maintenance essential:

Uniform Feeding: Ensure consistent feeding to prevent material blockage and overload.
Start Without Material: Start the machine when empty, then add materials.
Stopping Conditions: Only stop the machine after all materials are transported.
Avoid Large Blocks: Prevent hard, large materials from entering to avoid damaging the screw.
Regular Inspections: Check the operational status regularly and ensure all fasteners are secure.
Connection Checks: Pay special attention to bolts connecting the screw pipe flange and the shaft; address any issues promptly.
Safe Operation: Do not remove the cover during operation for safety.
Regular Lubrication: Ensure all moving parts receive regular lubrication.

Daily Maintenance

Perform maintenance at the start of each shift, taking about 10 minutes.
After 720 hours of operation, conduct a primary maintenance check, taking 4 hours.
After 2400 hours of operation, conduct a secondary maintenance check, taking 16 hours.

Use lubricants with the same properties as substitutes. Regularly clean the equipment to ensure the cleanliness of the drive mechanism and other components.

Conclusão

The LS screw conveyor is an efficient material handling device. With proper installation, operation, and maintenance, it can maximize performance and ensure long-term stable operation. For more information or inquiries, please contactar-nos. We are ready to provide you with professional support and services.

MAIS+

Rotary Kiln in Cement: Key Solutions

01/02

2025

01/02/2025

The rotary kiln is one of the most critical pieces of equipment in cimento production. It endures significant thermal loads and operates under a continuous production system. This situation demands high standards for equipment quality and operational practices. The operational condition of the rotary kiln directly affects the normal functioning of the entire production process.

Working Principle of the Rotary Kiln

The rotary kiln's body is theoretically inclined at an angle of 3 to 4 degrees on the supporting rollers. The center lines of the rollers must be parallel to the center line of the kiln. As the kiln rotates, its weight creates a downward force, causing a slow descent. The hydraulic thrust rollers help maintain a stable "floating" state, preventing local wear between the roller and the kiln shell. However, in practice, the kiln may experience abnormal movements due to factors like uneven foundation settlement, cylinder bending, equipment wear, and manufacturing errors.

Consequences of Abnormal Movement

Abnormal movements can lead to several negative consequences:

Temperature Increase: When the axial force on the rollers exceeds a certain limit, the thrust plates apply additional force to the bearing surfaces. This situation causes abnormal friction, leading to temperature increases. High temperatures can damage the oil film, resulting in poor lubrication and increased bearing temperatures.
Local Wear: Uneven contact surfaces between the rollers and the kiln shell may result in localized wear. This wear can cause vibrations in the rollers and may lead to slower rotation. Increased axial force can cause severe dry friction between the bearing surfaces, leading to temporary stops in the rollers and harmful sliding instead of normal rolling.
Hydraulic Thrust Roller Overload: Excessive downward force can overload the hydraulic thrust rollers, reducing their lifespan. Conversely, if the upward movement is too fast, it may damage the kiln’s tail seal, leading to serious accidents.

Soluções

To address abnormal movement in the rotary kiln, companies must pay close attention, identify the causes, and make necessary adjustments. Here are some practical strategies:

1. Comprehensive Inspection and Assessment

Begin with thorough inspections to identify which roller experiences the highest axial thrust. You can use the following methods:

Observe Gaps: Record the gaps between the roller and the guiding iron to determine the axial force direction.

Record Roller Axial Gaps: Check the gaps between the thrust plates and the bearing surfaces to assess the force on each roller.

Lead Wire Method: Use lead wire to check contact conditions between rollers and the kiln shell. Compare the width of the pressed lead wire to determine if the roller axes align with the kiln centerline.

2. Adjusting Friction Coefficient

You can apply different lubricants to the roller surfaces to change the friction coefficient. This adjustment can help control the kiln's movement. While this method is quick, it is not a long-term solution.

3. Adjusting Roller Axes

Use various techniques, such as graphical methods or hand signals, to determine the direction of adjustments needed for roller axes. Be cautious to avoid creating an "eight" shape with the rollers, as this can lead to increased torque and wear.

Conclusão

By observing and recording data carefully, you can identify the underlying issues and implement targeted solutions to resolve abnormal movements in the kiln. Regular inspections and maintenance will ensure the rotary kiln remains in a proper "floating" state. This approach reduces failure rates, extends service life, lowers energy consumption, and ensures production efficiency, ultimately achieving significant economic benefits.For further information or professional support, please feel free to contactar-nos. We look forward to providing you with quality services and solutions!

MAIS+

CONATCT

Dust Control for Screening Equipment

Dust Control for Belt Conveyors

System Control and Safety Measures

Site Survey and Customized Design

Installation and Maintenance

Conclusão

Working Principle of Rotary Unloading Valves

Structure of Rotary Unloading Valves

Maintenance Methods for Rotary Unloading Valves

1. Local Cooling Issues

2. Cement Caking Issues

3. Expansion Box Issues

Conclusão

Quality Control Methods and Experience in the Cement Grinding Process

1. Quality Control Methods

2. Quality Control Experience

2.1 Fineness

2.2 Specific Surface Area

2.3 Particle Distribution

2.4 Grinding Aids

Conclusão

Conditions for Dust Explosion

Anti-Explosion Measures

1. Explosion Prevention Measures

2. Structural Design Measures

3. Equipment Grounding and Explosion-Proof Components

4. Static Electricity Protection Measures

5. Detection and Fire Prevention Measures

6. Explosion Venting Devices

Calculation of Explosion Venting Area

Selection of Accessories

1. Selection of Anti-Static Filter Materials

2. Explosion-Proof Pulse Valves

3. Fire Extinguishing Devices

Causes of Belt Misalignment

1. Misalignment of Centers

2. Incorrect Roller Position

3. Improper Belt Joint

4. Misaligned Roller Frame

5. Belt Damage

6. Improper Discharge Point

7. Impact from Material Drop

8. Accumulated Material

9. Incorrect Roller Angle

10. Belt Quality Issues

11. Tensioning Device Issues

12. Aging from Long-Term Use

13. Frame Inclination

14. Equipment Vibration

15. Small Curvature Radius

Corrective Measures for Belt Misalignment

1. Working Principle and Characteristics of Cartridge Dust Collectors

1.1 Working Principle

1.2 Advantages

1.3 Disadvantages

2. Characteristics of Smoke and Dust in Various Steel Production Processes

2.1 Sintering Raw Material Area

2.2 Sintered Product and Ore Bin Area

2.3 Converter Steelmaking Area

2.4 Rolling Steel Production Area

2.5 Coking Production Area

2.6 Flux Production Area

3. Recommendations for Using Cartridge Dust Collectors in Steel Enterprises

Introdução

Signs of Buildup

Causes of Buildup

Solutions for Buildup

Conclusão

The Arching Phenomenon and Its Impact

Causes of Arching

Preventive Measures

1. Side Discharge Design

2. Reduce Internal Friction

3. Control Moisture

4. Dehumidification and Drying of Compressed Air

5. Increase the Angle of the Conical Section

6. Increase the Diameter of the Silo Outlet

Conclusão

Caraterísticas principais