Coated Polyester Duct Wall
A high-tenacity polyester base with PVC coating provides flexibility, surface cleanability, seam-welding compatibility and resistance to routine moisture and industrial handling.

A finished, collapsible flexible air duct engineered with continuous helix reinforcement to retain its airflow passage under suction, extraction and demanding temporary ventilation duties.
DERFLEX supplies project-configured duct assemblies for mines, tunnels, machinery, factories and mobile ventilation systems. Diameter, section length, wire pitch, coupling, suspension and material treatments can be matched to the operating plan and documented specification.
A spiral wire-reinforced ventilation duct is a flexible cylindrical air passage built around a continuous spring-steel helix. The wire holds the duct wall open when a fan creates negative pressure, while the flexible coated-textile body allows the assembly to bend, compress for transport and adapt to temporary or changing routes.
The distinction matters in underground and industrial ventilation. A layflat duct depends on internal positive pressure to inflate. A spiral-reinforced duct has mechanical support along its length, so the duct can be configured for extraction, suction or combined airflow systems where collapse resistance is required. The pitch and wire diameter influence the balance between flexibility, bend radius, weight and resistance to deformation.
DERFLEX treats the duct as a complete engineered product. The body material, wire, wear strip, seam method, suspension points and end connection are selected together so that the finished assembly corresponds to the installation environment rather than being assembled from unrelated components on site.
The value of a reinforced duct is created by the interaction of its wall, wire, wear protection and connection details.
A high-tenacity polyester base with PVC coating provides flexibility, surface cleanability, seam-welding compatibility and resistance to routine moisture and industrial handling.
The wire provides radial support. Tighter pitch can improve shape retention but also increases stiffness and weight; wider pitch increases flexibility but provides less support per unit length.
A protective strip can cover the wire path to reduce abrasion where the duct contacts the floor, tunnel wall, machinery or repeated handling points.
Zippers, hook-and-loop cuffs, rings, clamps or soft cuffs can be matched with single or double suspension details to suit installation speed and airflow direction.
The following range integrates the requested marketplace attributes with the parameters buyers need to define a finished spiral duct.
Finished flexible duct assembly for industrial, machinery, mining and tunnel ventilation applications.
| Product form | Complete flexible ventilation duct with formed body, spiral reinforcement, suspension details and selected end cuffs. |
|---|---|
| Product applications | Industrial sites, machinery ventilation, mining areas, tunnel construction, dust extraction, fume removal and temporary airflow distribution. |
| Body material | PVC-coated high-tenacity polyester textile; weight, tensile strength and coating formulation are selected by duty. |
| Reinforcement | Continuous spring-steel wire helix. Wire diameter and pitch are configured according to duct diameter, pressure and flexibility requirements. |
| Airflow mode | Configurations for negative-pressure extraction, positive-pressure supply or project-defined reversible operation. |
| Nominal diameter | 300–3000 mm reference range. The final available range depends on pressure, wire specification, section length and handling requirements. |
| Section length | Custom by project. Shorter reinforced sections are commonly selected where routing, bending or frequent relocation is expected. |
| Processing service | Cutting, forming, welding, reinforcement assembly, cuff installation, suspension reinforcement and finished-product packing. |
| Coupling options | Zipper cuff, hook-and-loop cuff, ring-to-ring connection, clamp cuff, wire-rope style connection or soft cuff. |
| Suspension | Single or double suspension line, reinforced tabs, loops or eyelet systems selected by diameter and installation route. |
| Wear protection | Optional external strip over the helix path and additional reinforcement at cuffs, suspension points and contact zones. |
| Color options | Orange, yellow, black and project colors, subject to material grade, order quantity and production confirmation. |
| Optional treatments | Flame-retardant, antistatic, anti-UV, anti-cold and anti-mildew formulations can be specified where relevant. Required standards and test methods must be defined before quotation. |
| Customization | Diameter, length, wire pitch, cuffs, suspension, color, labeling, packing and logo marking can be reviewed for OEM or project orders. |
Industrial buyers should evaluate a duct as part of a ventilation system, not only by fabric weight or diameter.
The helix supports the duct wall against inward deformation. Correct wire gauge and pitch are especially important for extraction lines, dust collectors and negative-pressure tunnel ventilation.
A reinforced duct can negotiate routes and equipment connections, but excessive compression or sharp bends increase pressure loss. The duct should be installed as open and straight as the site permits.
Wear strips and reinforced contact points help protect the duct where the wire path rubs against floors, walls, vehicles or repeated lifting locations.
The cuff affects installation speed, leakage potential, airflow direction and maintenance. It should be selected together with the fan outlet and adjacent duct sections.
The textile body can be compressed between wire turns, reducing storage volume compared with rigid ducting. Compression ratio varies with wire pitch, fabric stiffness and cuff design.
Where flame resistance or antistatic behavior is required, the order should identify the test standard, sample method and documentation expected rather than relying on a generic label.
Spiral reinforcement expands the design options beyond positive-pressure-only layflat ducting.
Fresh or conditioned air is pushed through the duct to a work zone, machine or enclosed area. The reinforcement helps the duct retain a controlled shape during routing and relocation.
Dust, fumes, smoke or contaminated air is drawn toward an extraction point. The steel helix helps resist collapse when pressure inside the duct falls below ambient pressure.
Some projects require airflow direction changes or coordinated supply and exhaust lines. The complete system—including fan behavior, cuffs and duct construction—must be reviewed for the intended reversal conditions.
The correct product depends on airflow direction, installation duration, available headroom and handling frequency.
| Selection factor | Spiral wire-reinforced duct | Layflat positive-pressure duct | Rigid or semi-rigid duct |
|---|---|---|---|
| Typical airflow role | Positive or negative pressure; combined duties by specification. | Mainly positive-pressure air supply. | Supply or extraction depending on system design. |
| Shape without airflow | Held open by wire helix. | Collapses flat when fan is off. | Retains fixed shape. |
| Flexibility | High; influenced by pitch and wire gauge. | Very high when unpressurized. | Lower; elbows and fittings usually required. |
| Transport volume | Compressible between wire turns. | Very compact when folded. | Highest transport and storage volume. |
| Ground contact | Wear strip is recommended for dragging or repeated contact. | Usually suspended; abrasion reinforcement may be added. | Resistant to deformation but heavier to move. |
| Best-fit projects | Extraction, dust collection, machinery links, short mine/tunnel sections and changing routes. | Long positive-pressure runs in mining and tunnel construction. | Permanent routes, high mechanical protection or fixed infrastructure. |
Each application should be matched to airflow volume, fan pressure, contaminants, temperature and movement conditions.
For local exhaust, dust collection and airflow routing where negative pressure may collapse unsupported textile ducting.
Flexible connection between blowers, extraction units, cooling equipment and temporary air-management systems.
Supply or exhaust ducting for factories, workshops, basements, construction zones and confined work areas.
State whether the duct supplies air, extracts air or must work with a reversible fan. Negative pressure and reversal influence the reinforcement and connection design.
Diameter should be determined from required airflow, air velocity, total duct length, bends, fittings and acceptable pressure loss—not selected by tunnel size alone.
A tighter pitch provides more support but creates a stiffer, heavier duct. A wider pitch provides easier movement but may not suit high suction or tight deformation requirements.
Tell us whether the duct will be suspended, dragged, laid on the floor or repeatedly relocated. Wear strip placement and local reinforcement can then be planned.
Zippers and hook-and-loop cuffs support fast assembly, while rings and clamps may suit robust mechanical connections. The cuff must match airflow direction and the adjacent equipment.
Where a flame test, antistatic limit or chemical restriction applies, provide the exact standard, acceptance criteria and documentation format so the correct material grade can be proposed.
DERFLEX combines coated-textile knowledge with custom conversion support for finished industrial flexible products.
Fabric structure, coating formulation and optional treatments are reviewed against the duty rather than selected from a generic description.
Cutting, welding, reinforcement, cuffs and suspension details are coordinated as one bill of materials.
OEM dimensions, colors, markings, packaging and connection details can be evaluated for recurring programs.
Critical dimensions, artwork, performance requirements and packing details can be confirmed before bulk production.
Six related internal resources connect finished duct selection with material, mining and tunnel ventilation topics.
Practical answers for engineers, contractors, distributors and equipment manufacturers.
It is for a finished flexible ventilation duct. The product includes the formed coated-textile body, spiral wire reinforcement, specified wear protection, suspension details and end connections. Fabric-only requirements should be quoted separately.
Yes, when the wire gauge, pitch, duct diameter and pressure rating are configured for the suction duty. The helix supports the duct wall against collapse, which is the key difference from a positive-pressure-only layflat duct.
A 300–3000 mm nominal diameter range is used as the project reference on this page. Final availability depends on pressure, wire reinforcement, section length, handling and production confirmation.
Tighter pitch generally provides more support and reduced deformation, while wider pitch improves flexibility and lowers the number of wire turns. Selection should consider negative pressure, duct diameter, bend radius, weight and relocation frequency.
Zipper, hook-and-loop, ring and clamp systems can all be used in appropriate designs. The best choice depends on installation speed, leakage control, fan connection, airflow direction, section replacement and local project practice.
Optional flame-retardant and antistatic material grades can be reviewed. The inquiry should state the required standard, test method, acceptance value and documentation so DERFLEX can confirm a suitable construction before production.
Yes. Diameter, section length, cuff geometry, clamp location, color, marking, packaging and logo can be evaluated around the fan outlet and the intended airflow system.
Please provide airflow direction, fan airflow and static pressure, duct diameter, total run, section length, bends, temperature, transported air or contaminants, installation method, coupling preference and any required fire or antistatic test standard.
Share your fan data, pressure direction, diameter, length, coupling and site conditions. DERFLEX will review the requested construction and prepare a project quotation based on confirmed specifications.
Fan datasheet, route sketch, duct diameter, section length, photos of the connection and required test standard.
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