October 2024

What is a bucket elevator？

Bucket elevators are popular vertical conveying devices. They primarily elevate powdered, granular, and small block materials. These elevators have high conveying efficiency, a compact structure, and a small footprint. They can lift materials to heights of 40 to 100 meters while remaining reliable. This reliability makes them essential in various industries, such as power generation, cement, metallurgy, machinery, chemicals, light industry, and agriculture.

Moreover, bucket elevators are widely used in the cement industry. Their small footprint, simple structure, large capacity, high lifting height, and low energy consumption contribute to their popularity. They are critical at different stages, including raw material storage, transportation, grinding systems, clinker feeding, cement grinding, and packaging. In modern large-scale cement production lines, bucket elevators are vital components in key positions.

Nantong Darko’s Expertise

Nantong Darko has ten years of experience in machinery manufacturing. We use advanced design principles to create our products. We also select high-quality steel and components. Additionally, we strictly control manufacturing precision to ensure reliable operation of our bucket elevators. Our product range includes NE type, TD type, TH/HL type, and dewatering scooping bucket elevators.

Classification of Bucket Elevators

1. By Layout

Vertical: The most common layout for conveying materials straight up.
Inclined: Suitable for scenarios requiring material elevation at a certain angle.

2. By Discharge Method

Centrifugal: Utilizes centrifugal force for discharge, suitable for conveying small, free-flowing materials, such as dry powders.
Gravitational: Relies on the weight of the material for discharge, suitable for large, heavy, and abrasive materials like ores and stones.
Mixed: Combines characteristics of both centrifugal and gravitational discharge methods, offering a wider application range.

3. By Feeding Method

Scoop: The bucket scoops material from the bottom; commonly used for conveying loose powders, granules, and small blocks.
Injection: Material is directly injected into the bucket, suitable for large and abrasive materials.

4. By Bucket Structure

Shallow Bucket: Wider and shallower bucket suitable for conveying damp, easily clumping, and poorly flowing materials.
Deep Bucket: Narrower and deeper bucket ideal for dry, loose, and easily spilled materials.
Triangular Bucket: With slanted walls, typically used for conveying large items.

5. By Traction Component

Belt: Low cost, light weight, and smooth operation, but with lower strength, not suitable for high-temperature or abrasive materials.
Steel Chain: High strength and wear resistance, suitable for high-temperature, heavy load, and abrasive materials.

Structure of Bucket Elevators

Bucket: Used for loading and elevating materials.
Traction Component: Such as belts or chains, which drive the movement of the buckets.
Drive Device: Provides power, typically including motors and reducers.
Upper and Lower Drums (or Sprockets): Change the direction of motion of the traction component.
Casing: Forms a closed transport channel to prevent material spillage and dust escape.
Tensioning Device: Adjusts the tension of the traction component to ensure normal operation.

Working Principle of Bucket Elevators

Bucket elevators scoop material from the storage area below with the buckets and elevate it to the top as the traction component (such as a conveyor belt or chain) moves. At the top, the bucket flips over and dumps the material into the receiving chute.

In belt-driven bucket elevators, the drive belt is typically made of rubber and installed on the drive drums and redirecting drums. Chain-driven bucket elevators usually have two parallel drive chains, with a pair of driving sprockets on either the top or bottom, and a pair of redirecting sprockets on the opposite side. To reduce dust escape, bucket elevators are typically equipped with a casing.

Precautions for Using Bucket Elevators

Strictly follow the principle of “no-load start, empty stop.” Ensure there is no material load before starting, and only feed materials once the machine is running smoothly. Empty the machine before stopping to avoid overload during the next start.
Feed uniformly to ensure unobstructed discharge. If a blockage is found, immediately stop feeding and address the issue.
Keep the bucket belt centered in the casing. If it drifts or becomes too loose, adjust it promptly using the tensioning device.
Prevent large foreign objects from entering the casing to avoid damaging the buckets. A metal grid can be installed at the feed inlet to block fibrous impurities like straw and rope.
Regularly check the tension of the bucket belt and the connection between buckets and the belt. If any looseness, detachment, misalignment, or damage is found, repair or replace it promptly to avoid more severe failures.
In case of sudden shutdown, first clear any accumulated materials in the casing before restarting to prevent excessive load during startup.

Understanding the classification, structure, principles, and precautions of bucket elevators is crucial. This knowledge ensures safe, efficient, and stable operation. If you have questions or need assistance, please contact us. Over the past ten years, Darko has introduced many innovations in vertical conveying technology. We have achieved significant progress in high-performance bucket elevators. Our experience and pioneering spirit have made us industry leaders in the design and manufacture of these elevators.

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Efficient Roller Press Solutions

10/26

2024

10/26/2024

What is a roller press used for?

The roller press, also known as a squeeze mill, roller mill, or double roller machine.A roller press is a grinding device used in industrial applications, particularly in cement production. It consists of two counter-rotating rollers that compress and grind the material. This process significantly reduces the particle size of the material, making it an efficient alternative to traditional grinding methods.

The roller press has high grinding efficiency, low energy consumption, and high output, making it widely used in the cement industry. However, during operation, various issues arise due to factors such as design, usage, and external conditions. These problems lead to poor working conditions, inadequate feed control, and hydraulic system failures, all of which negatively affect the performance of the roller press. To address these challenges, we analyze the root causes and implement improvements across multiple aspects, including design and usage. As a result, we optimize the modification process, enhance efficiency, and achieve better operational results.

I.Role of the Roller Press in Cement Plants

In cement plants, operators use the roller press to grind clinker and other raw materials into fine powder. Typically, they employ it alongside other grinding systems, such as ball mills, to enhance overall efficiency and reduce energy consumption. Furthermore, the roller press's capacity to manage high pressure and produce fine products makes it an essential component of modern cement production.

II.Differences Between Roller Press and Ball Mill

The primary difference between a roller press and a ball mill lies in their grinding mechanisms. A roller press compresses the material between two rollers under high pressure, resulting in lower energy consumption and higher efficiency. In contrast, a ball mill relies on the impact and friction of balls to grind the material, which typically consumes more energy. Therefore, roller presses usually perform better in terms of energy efficiency and product fineness.

III.Skew Issues in Roller Presses

Skew refers to the misalignment between the rollers of the roller press and may arise from mechanical wear or improper installation. This misalignment can lead to uneven pressure distribution, which ultimately reduces grinding efficiency. Therefore, regular maintenance and proper alignment are crucial for minimizing skew and ensuring the optimal performance of the roller press.

IV.Analysis of Issues with Roller Presses

1. Fine Powder Content at the Outlet

The fine powder content at the outlet of the roller press, also known as first-pass yield, directly reflects the effectiveness of the pressing process. However, many companies overlook this critical aspect. Testing samples from various enterprises revealed that the German BHS roller press achieved an outlet fineness of 33% on a 0.9mm sieve and 64% on a 0.08mm sieve (with 36% below 0.08mm). In contrast, many of these machines do not reach similar results.

2. Working Pressure

The pressing force is the most fundamental parameter determining the effectiveness of the roller press. To calculate the total force (in kN) of the roller press, we use the formula:

where:

n= number of hydraulic cylinders
S= effective area of the hydraulic cylinder (m²)
$P_{r}$ = hydraulic system pressure (MPa)

Moreover, the average roller pressure $P_{c p (in kN/m²) is given by:}$

$P_{c p =2F/}$ D⋅B⋅sinα

Here:

$D$ = diameter of the grinding roller (m)
$B$ = effective width of the grinding roller (m)
= pressure angle, also known as the bite angle (°)

Projected Pressure Calculation

In addition, the projected pressure PT (in kN/m²) is calculated using:

$P_{T} =F/ B \cdot D$

Impact of Maximum Roller Pressure on Pressing Efficiency

In practice, the maximum roller pressure significantly affects the pressing effect. Specifically, when the line connecting the centers of the two rollers is set at 0 degrees, the pressure angle starts at 8.3 degrees and ends at -1.6 degrees. Notably, the maximum peak pressure occurs at 1.5 degrees, slightly exceeding twice the average pressure.

Moreover, the hydraulic system of the roller press plays a crucial role, as it provides the dynamic roller pressure necessary to compress the material. This system consists of various components, including the oil station, hydraulic cylinders, nitrogen bags, solenoid valves, overflow valves, pressure gauges, oil lines, and control cabinet. If the configuration lacks damping adjustment valves and stroke adjustment valves, it cannot achieve optimal pressing results. Therefore, in some cases, adding small nitrogen bags may prevent the displayed pressure from accurately reflecting actual pressure changes.

Nitrogen Bag Configuration and Pressure Management

The size of the nitrogen bags and the piping must be calculated based on the size of the hydraulic cylinders. Furthermore, using pipes that are too small will increase resistance. In a parallel setup, when one large and one small nitrogen bag are used, the small bag activates first, followed by the large bag. As a result, this process repeatedly suppresses the opening of the roller gap, which operates in a cycle of retracting, retracting, and advancing, ultimately resulting in low pressing efficiency.

Moreover, the pressures of the nitrogen bags are set at 8, 10, and 12 MPa, meaning that only one nitrogen bag operates within a specific range while the other two become ineffective. Although this theory of differential pressure was initially proposed by German engineers, it failed to achieve the expected results due to significant variations in material properties. Consequently, the Germans did not pursue this approach further.

In general, it is advisable to set the nitrogen bag pressure at 60-80% of the system’s minimum pressure. This approach ensures that when the system operates at its lowest working pressure, a certain level of safety is maintained between the nitrogen bags and the on-off valve. However, the system’s operational state must be monitored on-site to determine its effectiveness. If the oil temperature is too high or too low, it indicates that the system is not in good working condition, which severely impacts pressing efficiency.

3. Roller Speed

The roller speed of the roller press can be expressed in two ways: one is the circumferential linear speed V of the rollers, and the other is the rotational speed of the rollers. The circumferential linear speed is related to output, power consumption, and operational stability. Generally, higher roller speeds lead to increased output; however, excessively high speeds can cause greater relative sliding between the rollers and the material, resulting in poor engagement and increased wear on the roller surfaces, which negatively impacts the output of the roller press.

Currently, the typical roller speed ranges from 1.0 to 1.75 m/s, with some experts suggesting that it should not exceed 1.5 m/s. The linear speed of the rollers usually falls between 1.0 and 1.7 m/s, with most operating around 1.5 to 1.7 m/s, and some even reaching 2.0 to 2.2 m/s. It is crucial to prioritize the squeezing effect when selecting the speed; this effect should be based on actual sampling. If the speed is too high, the pressing time shortens, leading to increased vibrations in the equipment. The significant variations in force become difficult to control, resulting in excessive power consumption without achieving the desired pressing effect.

4. Operating Gap and Material Properties

The operation of the roller gap is influenced by various factors, including the properties of the material (such as hardness, particle size, and moisture content), the form of the roller surface, the speed, the pressure, and the pressure control method. There are two ways to control the hydraulic cylinder pressure: constant pressure control and constant gap control. However, regardless of the method used, both are fundamentally flawed from a hydraulic perspective because pressure and gap continuously fluctuate.

The pressure gauge has a response time of 200 milliseconds, which complicates the control of the oil pump's pressure adjustments. This, in turn, affects the hydraulic cylinder pressure and subsequently the roller gap. As a result, there are two main issues: first, there is a lag in response; second, excessive pressure differentials occur. These factors hinder the stable operation of the roller press and negatively impact pressing efficiency.

5. Feeding Device

Currently, most roller presses use a feeding device that directs material straight from the hopper into the roller gap, pulling the material between the two rollers. This process is commonly referred to as the "pull-in angle" of the roller press. However, controlling the flow from two directions is not feasible, as the adjustment range is limited, making it difficult to achieve precise and stable control. Additionally, the other two directions cannot be adjusted at all. As a result, issues such as material segregation and roller misalignment frequently occur, leading to unmanageable conditions.

V.Roller Press System Modification Plan

1. Replacement of Feeding Device

Replace the roller press feeding device with a new type of four-direction feeding system (patented technology) to control the material feed. This system allows for adjustment and control from two directions, enabling reasonable control of material flow. The other two directions can be adjusted to correct the lateral gap deviation between the rollers, reducing the impact of the material on the roller press and facilitating the formation of a stable material bed. This approach eliminates issues such as material segregation and roller misalignment, and it operates at a low hopper position, making it easier to adjust and control.

2. Upgrading the Hydraulic System

We replaced the hydraulic system of the roller press, including components such as the oil station, overflow valve, pressure gauge, accumulator (nitrogen bag), and valve assembly. Additionally, we incorporated damping adjustment valves and stroke adjustment valves (patented technology) to make the hydraulic system flexible, rigid, and controllable.

During the research and development process, we conducted extensive field tests using a specialized high-precision pressure measurement device (1000 Hz) to collect and analyze data. We employed dedicated simulation software and complex mathematical models to successfully develop a dual-channel adjustable damping anti-vibration regulation mechanism, achieving a reasonable balance of rigidity and flexibility in the hydraulic system.

3. Implementing PLC Control

We replaced the roller press hydraulic PLC and implemented four-directional control of the feeding device, utilizing a constant power control method for easier centralized operation. We configured the system with Siemens SIMATIC S7-1200, integrating Siemens SINAMICS drive products and SIMATIC human-machine interface products. The CPU comes standard with an Ethernet interface that supports various industrial Ethernet communication protocols, including PROFINET, TCP, UDP, and Modbus TCP.

Our company developed this technology through mathematical modeling, gathering extensive field data during the research and development process. We employed specialized simulation software and complex mathematical models, which have been validated through practical application.

VI.Case Studies

1. Chao Lake Hengxin Cement Co., Ltd.

Since the modification in August 2020, production efficiency has increased from 200 tons/hour to 290 tons/hour, with energy consumption controlled at 22 kWh/ton of cement.

2. Hainan Huaren Cement

In June 2022, the roller press was upgraded, increasing hourly output from 150-160 tons to 180-200 tons, with energy consumption reduced to about 23 kWh/ton.

3. Guizhou Southwest

Through the upgrade, output has risen to 180-190 tons/hour, and energy consumption decreased from 32 kWh/ton to 25 kWh/ton.

4. Jiangxi Sanqing Cement Co., Ltd.

After the modification, the output increased to 270-280 tons/hour, with stable operation and nitrogen bag temperatures maintained at 40-60°C.

VII.Benefits of Roller Press Technology Upgrade and Modification

The stability of the roller press has improved, with virtually no side leakage. There are three methods for adjusting roller skew: first, four-directional feed adjustment; second, hydraulic system adjustments; and third, separate pressure adjustments for left and right. Control is stable, with minimal occurrences of material collapse and roller skew.

The hydraulic system of the roller press is flexibly adjustable and controllable. The fluctuation of the roller gap has changed from slow retraction and fast advance to fast retraction and slow advance, increasing pressing efficiency. The fine powder content at the roller press outlet has increased by 3-7%, the specific surface area of the input material has improved, and hourly output has increased by 10-20%.

A constant power control method is used, with operational power maintained at 85±5% of the rated power. The efficiency of the roller press has two requirements: first, high operational power; second, high first-pass yield. By improving the efficiency of the roller press and reducing mill power consumption, the overall energy consumption has been lowered by 2-5 kWh/ton.

If you have needs regarding the modification and upgrading of roller press systems, please feel free to contact us at Darko. We will provide you with professional solutions and support.

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How To Choose The Right Conveyor System?

10/21

2024

10/21/2024

In industrial production, selecting the right conveyor system is crucial. Each type of conveyor system has its advantages and disadvantages, suiting various materials and process requirements. This article will compare chain conveyors, air slide conveyors, and belt conveyors to help you make informed choices in powder conveying.

1. Chain Conveyor: Efficient Powder Handling

1.1 What is a Chain Conveyor?

The Chain Conveyor (model FU) is a new type of conveyor system designed to replace traditional screw conveyors. Its design overcomes many shortcomings of screw conveyors, particularly in sealing and wear resistance.

1.2 How Does a Chain Conveyor Work?

The FU chain conveyor drags materials using a continuous chain within a wide and high trough. The friction between materials pushes them forward, ensuring efficient transportation. This conveying principle is more advanced than that of screw conveyors and better suits modern production needs.

1.3 Advantages of Chain Conveyors

The rise of large-scale new dry cement creates new demands for powder conveying equipment. The FU chain conveyor can handle transportation needs from dozens to thousands of tons. However, when the transportation distance exceeds thirty or forty meters, power consumption and wear on components increase, making the FU chain conveyor seem less effective as a conveyor system. If you have concerns or needs regarding large-scale production, please contact us for the best solutions.

2.Air Slide Conveyor: An Efficient and Convenient Solution

2.1 What is an Air Slide Conveyor?

An air slide conveyor is used to transport easily fluidized powder materials (such as cement and fly ash). It utilizes airflow to convey granular materials and has three types: suction, pressure, and mixed flow.

2.2 How Does an Air Slide Conveyor Work?

The air slide conveyor uses the kinetic energy of airflow to make granular materials float and transport along the pipeline. When a high-pressure fan injects air into the permeable layer, materials are fluidized, reducing internal friction and enhancing flowability.

2.3 Applications of Air Slide Conveyors

Due to its low energy consumption and high efficiency, the air slide conveyor has become a cost-effective choice in the powder conveying field. It is widely used for transporting easily fluidized powder materials like cement and fly ash. However, installation requires a specific incline angle and must ensure that material moisture and particle size are within appropriate ranges.

3.Belt Conveyor: Versatile Bulk Transport

3.1 What is a Belt Conveyor?

A belt conveyor is ideal for bulk and granular materials. Its simple design and stable structure keep operational resistance low. The rolling friction between the belt and idlers reduces energy consumption and equipment wear.For an example of a successful implementation, see the Inner Mongolia Meifang Energy Co., Ltd DTII Belt Conveyor Project.

3.2 How Does a Belt Conveyor Work?

A belt conveyor transports materials continuously by using the belt and idlers together. It works efficiently for large volumes, long distances, and directional changes, making it widely applicable.

3.3Advantages and Disadvantages of Belt Conveyors

Belt conveyors excel in conveying powder materials. However, they can have challenges, such as sealing issues and high labor intensity for cleaning accumulated materials. These factors make many companies cautious when selecting them. In situations with high volume and long distances, belt conveyors are reasonable choices, but environmental pollution is a concern. If you face these challenges, the Darko team is ready to help.

4.Comparing the Three Major Conveying Equipment

Air slide conveyors, FU chain conveyors, and belt conveyors are the three "gems" in the powder conveying field. Air slide conveyors are preferred due to their low investment and operating costs, especially when material moisture and particle size are suitable. The chain conveyor is suitable for smaller volumes and shorter distances, though it has higher energy consumption. In applications requiring high volume and long distances, belt conveyors are indispensable, but concerns regarding sealing and environmental impact must be addressed.

5.A New Solution: Air Chain Conveyor

Recently, Darko launched the air chain conveyor, which fills the gaps left by traditional conveying equipment. This new design combines the benefits of chain conveyors and air slide conveyors. It adds an air chamber and permeable layer at the bottom. High-pressure air fluidizes materials and reduces internal friction, allowing for high volume and long-distance conveying.

The enclosed design of the air chain conveyor prevents material spillage, solving the problems traditional equipment often faces during operation. As a result, many companies are now choosing this solution.

6.How to Find the Perfect Conveyor System for Your Company’s Needs?

Do you need assistance in using conveying systems to transport bulk materials such as cement, asphalt, and grains? We design, manufacture, and install various types of conveying systems to meet your company’s needs. If you have any questions, please contact Darko.We look forward to providing you with professional services and support.We can provide customized solutions based on your company's requirements.

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Key Tips for Installing Bag Dust Collectors

10/12

2024

10/12/2024

When you install bag dust collectors, keep a few key points in mind. This will help ensure efficient operation and easy maintenance. Ultimately, proper installation improves air quality and boosts productivity in industrial settings.

1. Layout of the Dust Collection System

The layout of your dust collection system is crucial. Therefore, follow these principles for the best results:

Proximity of Dust Sources: First, combine dust sources into one system if they are close together and operate simultaneously. This approach reduces ducting and enhances efficiency.

Different Types of Dust: Additionally, if dust sources produce different types of dust but operate at the same time, create a single system if mixed recovery is possible. This simplification benefits overall operations.

Temperature and Humidity Variations: Moreover, install separate systems for dust-laden gases with varying temperatures and humidity. This can prevent condensation in the ducts, which might lead to operational issues.

When many dust sources exist, set up the dust collection system in concentrated zones. Each system should connect to a limited number of exhaust points. If you cannot achieve hydraulic balance through adjustments, consider installing balancing valves on branches with lower resistance. Furthermore, place these valves on vertical ducts to enhance performance.Talk to us if you are dealing with these challenges.

Calculate the exhaust volume based on the maximum simultaneous exhaust volume and the leakage volume from intermittent points. Ensure each intermittent point has valves linked to the process equipment. Additionally, maintain leakage volume at 15% to 20% of normal exhaust volume when the valves are closed.

Note: When designing multiple exhaust cabinets as one system, determine the system's airflow based on the total airflow of the cabinets used at the same time. Install a valve for airflow regulation at each exhaust cabinet's outlet. Also, ensure that the fan has variable frequency drive capabilities.

2. Types of Dust Collection Systems

Bag dust collectors can be classified into three types based on production processes, equipment layout, and exhaust volume:

Local Dust Collection: For example, install bag dust collectors directly near production equipment. This setup captures and recovers dust on-site. It requires minimal or short ducting, making it efficient.

Dispersed Dust Collection System: In contrast, when exhaust points in a workshop are spread out, combine appropriate exhaust points based on the nature of the conveyed gases. Therefore, position the industrial dust collectors and fans as close as possible to the dust-generating equipment. This approach leads to shorter ducts and easier pressure balance.

Centralized Dust Collection System: This system is suitable for workshops with concentrated dust sources. In this case, centralize all exhaust points or arrange several dust extraction systems together. Centralized systems simplify dust handling and maintenance. However, they often require longer and more complex ducting, which can be a drawback.

Application in Cement Plants

In cement plants, bag dust collectors play a vital role in several areas:

Raw Material Handling: They capture dust generated during the processing and transportation of raw materials like limestone and clay.

Milling Process: During the grinding of cement clinker and other materials, these collectors effectively manage the fine dust produced.

Mixing and Packaging: Bag dust collectors control dust emissions during mixing and packaging, ensuring a clean environment and high product quality.

Kiln Emissions: They help in purifying exhaust gases from the kiln, reducing air pollution and adhering to environmental regulations.

3. Layout Guidelines for Dust Collectors

When laying out your bag dust collectors, follow these principles:

First, position the dust collector above equipment like belt conveyors and hoppers if you can integrate the collected dust into the production process. This improves workflow significantly.

Alternatively, if the collected dust cannot easily integrate, place the dust collector in a suitable location with a dust storage bin. This ensures easy access for maintenance.

Additionally, locate dust collectors in the negative pressure section of the system. If they are in a positive pressure section, use exhaust fans to manage airflow effectively.

Ensure the pressure loss at each exhaust point does not exceed 10%. If you cannot achieve this through adjustments, consider installing airflow regulation devices to maintain efficiency.

Finally, for wet gas purification equipment at risk of freezing, implement anti-freezing measures. In colder regions, install wet gas purification equipment indoors.

Note: Position flue gas dust collectors outdoors to ensure proper operation.

Make sure that the dust discharge pipes of dry dust collectors and the wastewater discharge pipes of wet dust collectors have measures to prevent air leakage. This helps maintain efficiency and safety.

Allowable deviations and inspection methods for dust collector installation

Item No.	Project	Allowed Deviation (mm)	Inspection Method
1	Horizontal Displacement	≤10	Theodolite or cable and ruler inspection
2	Elevation	±10	Level, straight line and ruler inspection
3	Verticality	≤2 per meter	Hanging wire and ruler inspection
4	Total Deviation	≤10

4. Installation Requirements for Bag Dust Collectors

To install your bag dust collectors effectively, follow these requirements:

Confirm that the installation position is correct and that the unit is securely fixed. Allowable deviations should meet relevant standards for safety and performance.

Furthermore, ensure that moving or rotating parts operate flexibly and reliably. This step is essential for long-term reliability.

The installation of ash discharge valves, unloading valves, and sludge discharge valves should be tight for easy operation and maintenance. This facilitates easy access for cleaning and upkeep.

For the on-site assembly of bag dust collectors, meet these requirements:

Seal the outer shell properly. Additionally, ensure the filter bag interfaces are secure to prevent dust leakage.

For compartmentalized reverse-blowing bag dust collectors, install the filter bags straight. Maintain the tension on each filter bag at 30N/m ± 5N/m to ensure optimal performance.

For mechanical rotary flat bag dust collectors, ensure the rotating arms operate smoothly. The top cover of the clean air chamber should be well-sealed.

Finally, for pulse bag dust collectors, align the blowing nozzle with the center of the venturi tube. Allow a deviation of no more than 2mm.

At Darko, we provide high-quality bag dust collectors and dust collection systems tailored to your industrial needs. Our expertise ensures optimal performance, efficiency, and compliance with environmental standards. We are dedicated to helping you maintain a clean and safe working environment.

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How to Effectively Use Cyclone Dust Collectors?

10/07

2024

10/07/2024

Cyclone dust collectors (also referred to as a cyclone separator or simply a cyclone) are essential in various industrial applications for controlling air quality and minimizing dust emissions. The efficiency of these cyclonic systems hinges on the precise dimensions and relationships of their components.

In this blog, we’ll explore the critical factors that influence the performance of cyclone dust collectors, along with best practices for installation and usage.

WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF CYCLONE DUST COLLECTORS?

Advantages

1. Dry Cleaning Method: The dry cleaning method facilitates the centralized treatment and recycling of dust.

2. Corrosive Dust Handling: Cyclone can be used to treat corrosive dust gas.

3. Compact Design: The cyclone separator is small and occupies less space, therefore making it easy to install. Additionally, it has a simple structure and is relatively inexpensive.

4. User-Friendly: The cyclone structure is not complex, making it easy to use.

5. High-Temperature Gas Purification: Cyclone can purify high-temperature dusty gases. The cyclone dust collector made of carbon steel can handle gas temperatures up to 100°C, while those with refractory materials can process gases at 500°C.

Disadvantages

1. Limited Handling Capacity: Due to the small handling capacity of a single cyclone dust collection unit, multiple cyclone collection units need to be connected in parallel for larger volumes.

2. Ineffective on Fine Dust: A cyclone separator is not suitable for treating dust particles smaller than 5μm. For light dust particles and high filtration efficiency, baghouse filters are the preferred choice.

3. Not Suitable for Sticky Dust:The cyclones are ineffective in purifying sticky dust particles.

WHAT ARE THE FACTORS AFFECTING THE EFFICIENCY OF A CYCLONE?

1. Inlet Size

The inlet is a crucial component of a cyclone dust collector, significantly impacting dust removal efficiency. A smaller inlet area increases airflow velocity, which enhances dust separation from other particles.

2. Diameter and Height of the Cyclone Cylinder

The diameter and height of the cylindrical body influence the efficiency of the cyclone.With a constant rotational airflow speed, a larger diameter results in reduced centrifugal force on the dust particles. This leads to lower dust removal efficiency and makes it harder for dust to be drawn into the machine. Therefore, the inlet diameter should not be excessively large or too small. A suitable size is essential to avoid clogging by larger dust particles.

3.Diameter and Depth of the Exhaust Pipe

The diameter and depth of the exhaust pipe also affect cyclone dust removal efficiency. A smaller diameter in the exhaust pipe restricts airflow, making it more difficult for dust to exit. To improve efficiency, it's important to increase the exhaust velocity and the pipe diameter.

HOW DO YOU CHOOSE A CYCLONE SEPARATOR?

1.Matching Purification Capacity

The actual amount of dust-laden gas to be processed should match the capacity of the cyclone dust collector. Therefore, when you select the diameter of the cyclone dust collector, keep it as small as possible. If you require a larger airflow, then you can use several smaller diameter cyclone dust collectors in parallel.

2.Inlet Airspeed

The inlet airflow velocity should be maintained between 18 and 23 m/s. If the velocity is too low, dust removal efficiency will decrease. On the other hand, if the velocity is too high, resistance loss will increase. And power consumption will also rise, resulting in little improvement in dust removal efficiency.

3. Low Resistance Loss

You should select a cyclone dust collector with low resistance loss. Additionally, it should have low power consumption. Finally, it should feature a simple structure for easy maintenance.

4. Minimum Dust Particle Capture

The cyclone dust collector should capture the smallest dust particle size. This size should be slightly smaller than the particle size in the gas being processed.

5. High-Temperature Dust-Laden Gas

When you deal with high-temperature dust-laden gas, you should apply insulation. This prevents moisture from condensing inside the collector. If the dust does not absorb moisture and the dew point is between 30°C and 50°C, you should set the collector temperature at least 30°C higher. If the dust is hygroscopic (such as cement, gypsum, or alkaline dust) and the dew point is between 20°C and 50°C, you should maintain the collector temperature 40°C to 50°C above the dew point.

6. Sealed Structure

You should ensure that the cyclone dust collector has a well-sealed structure to prevent any air leakage, especially during negative pressure operations. Additionally, you should emphasize the reliability of the discharge lock device.

7. Explosion-Proof Measures

For flammable and explosive dust (such as coal dust), explosion-proof measures should be in place. A common practice is to install a safety explosion-proof valve in the inlet pipeline.

8. Dust Concentration Limits

When the dust is less viscous, you can relate the maximum allowable mass concentration of dust to the diameter of the cyclone. Specifically, a larger diameter allows for a higher allowable mass concentration.

WHAT ARE THE INSTALLATION POINTS?

1.Ensure Uniform Airflow Distribution

When combining multiple cyclone dust collectors, it is essential to maintain uniform airflow to prevent short-circuiting. The inlet, hopper, and outlet zones must be properly sealed to avoid air leaks.

2.Material Selection

Depending on the operational conditions, cyclone dust collectors can be constructed from various materials, including steel, organic plastics, and ceramics. Selecting the right material is crucial for ensuring durability and resistance to wear and tear.

3.Positioning in Series

When connecting cyclone dust collectors in series, they should be arranged based on their performance. High-efficiency collectors should be placed first to capture the majority of the dust before it reaches lower-performing units.

HOW DO YOU MAINTAIN YOUR CYCLONE SEPARATOR?

I. Stable Operating Parameters

The operating parameters of a cyclone dust collector mainly include the inlet airflow velocity, the temperature of the gas being processed, and the inlet mass concentration of dust-laden gas.

♦Inlet Airflow Velocity

For a cyclone dust collector of fixed dimensions, increasing the inlet airflow velocity improves the gas handling capacity. It also effectively enhances separation efficiency. However, this increase also raises the pressure drop. Once the inlet airflow velocity reaches a certain value, the separation efficiency may decline. Additionally, wear may increase, and the lifespan of the cyclone dust collector may shorten. Therefore, you should maintain the inlet airflow velocity in the range of 18 to 23 m/s.

♦Temperature of the Processed Gas

As gas temperature increases, its viscosity rises, which increases the centripetal force acting on dust particles, leading to a decrease in separation efficiency. Therefore, cyclone dust collectors operating under high-temperature conditions should have a larger inlet airflow velocity and a smaller cross-sectional flow rate.

♦Inlet Mass Concentration of Dust-Laden Gas

A higher concentration of larger dust particles significantly carries smaller dust particles, which improves separation efficiency.

II. Preventing Air Leakage

Air leakage in a cyclone dust collector can severely impact dust removal efficiency. For instance, experts estimate that a 1% air leak at the lower cone or the discharge valve will decrease dust removal efficiency by 5%. Moreover, if a 5% leak occurs, the efficiency will drop by 30%. You can find air leakage in three areas. These areas are at the inlet and outlet flanges, in the body of the cyclone dust collector, and at the discharge mechanism.

The causes of air leakage include:

Flange Leakage: This is mainly caused by loose bolts, uneven gasket thickness, or irregular flange surfaces.

Body Leakage: The primary reason for leakage in the dust collector body is wear, particularly in the lower cone. Experience shows that when the mass concentration of dust-laden gas exceeds 10 g/m³, a 3 mm thick steel plate can wear out in less than 100 days.

Discharge Mechanism Leakage: This is mainly due to poor sealing in mechanical automatic discharge valves (e.g., weight-operated valves).

III. Preventing Wear in Key Areas

Factors affecting wear in critical areas include load, airflow velocity, and dust particle characteristics. The wear-prone areas include the casing, cone, and discharge outlet. Technical measures to prevent wear include:

Preventing Discharge Outlet Blockage: This mainly involves selecting high-quality discharge valves and regularly adjusting and maintaining them.

Preventing Excessive Gas Backflow into the Discharge Outlet: The discharge valves should be tightly sealed and properly weighted.

Regular Inspections: Frequent checks for air leaks due to wear should be conducted to take timely corrective measures.

Using Replaceable Wear Plates: In high-impact areas, install replaceable wear plates or increase the wear-resistant layer.

Minimizing Welds and Joints: Reduce the number of welds and joints; existing welds should be ground smooth, and flanges should have matching inner diameters and maintain good alignment.

Maintaining Airflow Velocities: The tangential velocity of airflow at the cyclone dust collector wall and the inlet airflow velocity should be kept within the critical range.

IV. Avoiding Dust Blockage and Buildup

Blockages and dust buildup in cyclone dust collectors mainly occur near the discharge outlet and in the intake and exhaust pipelines.

Discharge Outlet Blockage and Prevention Measures: Blockages at the discharge outlet are typically caused by two factors:

large materials or debris (such as shavings, wood chips, plastic bags, shredded paper, rags, etc.) getting stuck at the discharge outlet, leading to dust accumulation around them.
excessive dust accumulation in the hopper that has not been discharged in time. Preventive measures include adding a mesh at the intake and creating access holes above the discharge outlet (with covers and gaskets sealed with adhesive).

Intake and Exhaust Blockage and Prevention Measures: Improper design often causes blockages at the intake and exhaust ports. Rough right angles or slanted angles at the ports can lead to ash adhesion and buildup. This buildup eventually causes blockages.

CONCLUSION

Cyclone dust collectors are a vital component of effective dust management in industrial settings. By understanding the key design elements, adhering to installation best practices, and implementing innovations from Darko, operators can significantly enhance performance and efficiency. Regular maintenance and attention to detail will ensure that these systems operate at their best, providing a cleaner and safer working environment.

If you have any questions or would like to learn more about cyclone dust collectors and their applications, feel free to reach out.

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What is a bucket elevator？

Nantong Darko’s Expertise

Classification of Bucket Elevators

1. By Layout

2. By Discharge Method

3. By Feeding Method

4. By Bucket Structure

5. By Traction Component

Structure of Bucket Elevators

Working Principle of Bucket Elevators

Precautions for Using Bucket Elevators

What is a roller press used for?

I.Role of the Roller Press in Cement Plants

II.Differences Between Roller Press and Ball Mill

III.Skew Issues in Roller Presses

IV.Analysis of Issues with Roller Presses

1. Fine Powder Content at the Outlet

2. Working Pressure

Projected Pressure Calculation

Impact of Maximum Roller Pressure on Pressing Efficiency

Nitrogen Bag Configuration and Pressure Management

3. Roller Speed

4. Operating Gap and Material Properties

5. Feeding Device

V.Roller Press System Modification Plan

1. Replacement of Feeding Device

2. Upgrading the Hydraulic System

3. Implementing PLC Control

VI.Case Studies

1. Chao Lake Hengxin Cement Co., Ltd.

2. Hainan Huaren Cement

3. Guizhou Southwest

4. Jiangxi Sanqing Cement Co., Ltd.

VII.Benefits of Roller Press Technology Upgrade and Modification

1. Chain Conveyor: Efficient Powder Handling

1.1 What is a Chain Conveyor?

1.2 How Does a Chain Conveyor Work?

1.3 Advantages of Chain Conveyors

2.Air Slide Conveyor: An Efficient and Convenient Solution

2.1 What is an Air Slide Conveyor?

2.2 How Does an Air Slide Conveyor Work?

2.3 Applications of Air Slide Conveyors

3.Belt Conveyor: Versatile Bulk Transport

3.1 What is a Belt Conveyor?

3.2 How Does a Belt Conveyor Work?

3.3Advantages and Disadvantages of Belt Conveyors

4.Comparing the Three Major Conveying Equipment

5.A New Solution: Air Chain Conveyor

6.How to Find the Perfect Conveyor System for Your Company’s Needs?

1. Layout of the Dust Collection System

2. Types of Dust Collection Systems

Application in Cement Plants

3. Layout Guidelines for Dust Collectors

4. Installation Requirements for Bag Dust Collectors

WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF CYCLONE DUST COLLECTORS?

Advantages

1. Dry Cleaning Method: The dry cleaning method facilitates the centralized treatment and recycling of dust.

2. Corrosive Dust Handling: Cyclone can be used to treat corrosive dust gas.

3. Compact Design: The cyclone separator is small and occupies less space, therefore making it easy to install. Additionally, it has a simple structure and is relatively inexpensive.

4. User-Friendly: The cyclone structure is not complex, making it easy to use.

5. High-Temperature Gas Purification: Cyclone can purify high-temperature dusty gases. The cyclone dust collector made of carbon steel can handle gas temperatures up to 100°C, while those with refractory materials can process gases at 500°C.

Disadvantages

1. Limited Handling Capacity: Due to the small handling capacity of a single cyclone dust collection unit, multiple cyclone collection units need to be connected in parallel for larger volumes.

2. Ineffective on Fine Dust: A cyclone separator is not suitable for treating dust particles smaller than 5μm. For light dust particles and high filtration efficiency, baghouse filters are the preferred choice.

3. Not Suitable for Sticky Dust:The cyclones are ineffective in purifying sticky dust particles.

WHAT ARE THE FACTORS AFFECTING THE EFFICIENCY OF A CYCLONE?

1. Inlet Size

2. Diameter and Height of the Cyclone Cylinder

3.Diameter and Depth of the Exhaust Pipe

HOW DO YOU CHOOSE A CYCLONE SEPARATOR?

1.Matching Purification Capacity

2.Inlet Airspeed

3. Low Resistance Loss

4. Minimum Dust Particle Capture

5. High-Temperature Dust-Laden Gas

6. Sealed Structure

7. Explosion-Proof Measures

8. Dust Concentration Limits

WHAT ARE THE INSTALLATION POINTS?