| Aspiration cyclone, flexible ducts
Cyclones and Flexible Ducting for Dust Collection Systems
Cyclones and flexible ducting (hoses) are important components of industrial dust collection (aspiration) systems. Cyclones provide primary air cleaning by removing large particles, while flexible ducts are used to conveniently connect equipment to the main line of rigid ductwork.
The correct selection of these elements directly affects the cleaning efficiency, energy consumption of the system, and operational safety, especially when working with combustible dust.
Cyclones
A cyclone is a simple and reliable device for mechanical, inertial air cleaning to remove relatively large and heavy suspended particles (shavings, sawdust, coarse dust).
Operating Principle
Contaminated air is fed tangentially into the cylindrical body of the cyclone, creating a powerful vortex flow. Under the action of centrifugal force, heavier and larger dust particles are thrown against the walls, lose velocity, and settle under gravity into the lower conical collection hopper. Air cleaned of coarse fractions exits through the central exhaust outlet at the top.
Efficiency and Role in the System
Cyclones effectively capture particles larger than 10 μm (with 80-95% efficiency) but capture very little fine, more harmful dust. In modern systems required to meet strict environmental emission standards (IED Directive), cyclones cannot be used as the sole or final cleaning device.
Their main role is pre-cleaning (pre-filtration). Installing a cyclone before the main, finer filter (e.g., a baghouse filter) allows for:
- Reducing the overall dust load on the filter.
- Protecting the filter media from rapid wear caused by large abrasive particles.
- Extending the maintenance intervals for the main filter.
Main Types of Cyclones
Cyclones are classified based on various parameters, including body design (cylindrical, conical), flow rotation direction, and air inlet method. The choice of a specific type depends on the dust characteristics and efficiency requirements.
What to Consider When Choosing a Cyclone
- Capacity (m³/h): Must match the total airflow rate of your dust collection system.
- Type and Size of Particles Captured: Cyclones are most effective for dry, non-sticky dust of coarse and medium fractions.
- Pressure Drop: Affects the overall energy efficiency of the system (lower pressure drop means less load on the fan).
- Body Material: Typically carbon steel or stainless steel; the choice depends on the abrasiveness of the dust and environmental conditions.
- Dimensions and Sediment Discharge Method: Important for integrating the cyclone into the existing workshop space.
Flexible Ducting (Hoses)
Flexible ducts are used to connect end-use equipment (machines, workstations, extraction arms) to the main ductwork of the aspiration system. Their flexibility allows for easy routing in tight spaces, connection to moving parts, and vibration dampening.
Materials and Characteristics
The choice of flexible duct material is critical and depends on the operating conditions:
- Polyurethane (PU): Offers high abrasion resistance and good flexibility. Ideal for extracting wood shavings, chips, granules, and abrasive dust. Available in various wall thicknesses for different loads.
- PVC: Generally less wear-resistant than PU but more resistant to certain chemicals. Suitable for light dust, fumes, gases, and ventilation of air without abrasive particles.
Comparison of Main Flexible Duct Materials (Typical Properties)
| Material |
Abrasion Resistance |
Heat Resistance |
Flexibility |
Chemical Resistance |
| Polyurethane (PU) |
High |
Medium (up to ~100-125°C) |
High |
Good (oils, solvents) |
| PVC |
Medium/Low |
Low (up to ~70-80°C) |
High |
High (acids, alkalis) |
Selection Criteria
- Type of Medium Conveyed: Determines the requirements for abrasion, heat, and chemical resistance.
- Diameter and Length: Must match the system's design parameters.
- Need for Antistatic Properties (ATEX): Mandatory for combustible dust.
- Operating Conditions: UV resistance (for outdoor installation), resistance to oils, etc.
- Bend Radius: Important for installation in confined spaces.
Safety Requirements: Antistatic Execution (ATEX)
When transporting many types of dust (wood, plastic, flour, etc.) through flexible polymer ducts, there is a risk of static electricity accumulation. This can lead to a spark and, consequently, ignition of the dust-air mixture.
ATEX Directive: For operation in potentially explosive atmospheres, all system components, including flexible ducts, must be antistatic and comply with the ATEX Directive 2014/34/EU.
- Conductive Materials: Antistatic ducts are made from special materials that do not accumulate charge or have an integrated copper or steel wire helix to dissipate it to ground.
- Mandatory Grounding: The helix or conductive layer of an antistatic hose must be securely grounded at both ends when connected to the system.
Important: Using standard (non-antistatic) plastic or polyurethane ducts in areas where there is a risk of combustible dust explosion does not comply with safety regulations.
Equipment Selection and Installation
Selection and Special Versions: Our engineers can help select the optimal cyclone model and type of flexible duct for your specific needs. In addition to standard products, we can assist with ordering special versions, such as antistatic (ATEX) hoses or stainless steel cyclones.
Professional Installation: SIA "Akvilon" offers professional installation services for dust collection systems. Our specialists ensure the correct installation of cyclones, connection of flexible ducts, sealing of all joints, and commissioning to guarantee the designed efficiency of the entire system.
Ordering and Selection
Our engineers will help select the appropriate cyclone and type of flexible duct for your dust collection system, considering capacity, dust type, and safety requirements (including ATEX).
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