DERFLEX manufactures flexible ventilation duct assemblies for mining, tunneling, underground construction and temporary industrial air movement. Each quotation is built around the fan, pressure direction, route geometry, connection format and required test method��so the delivered duct can arrive as a coordinated installation package rather than an unspecified tube.
Body material, reinforcement, welding, suspension and end connections are reviewed as one finished product.
Procurement problems often begin when a duct is purchased by diameter alone. Two ducts with the same nominal size can behave very differently when the pressure direction, wire pitch, seam layout, suspension spacing or fan connection changes.
DERFLEX therefore treats the inquiry as an airflow and installation brief. The objective is to translate fan data and site constraints into a repeatable production specification that purchasing teams can approve, installers can understand and future replacement orders can reference.
Confirm whether the system forces fresh air, extracts contaminated air or requires both modes in different sections.
Select a collapsible layflat body, a helix-supported suction duct or an oval geometry for restricted headroom.
Define cuffs, zippers, rings, suspension points, reducers, branches, markings and packing before production.
A flexible ventilation duct manufacturer should help separate forced-air supply from suction duty, because reinforcement and collapse resistance are determined by the operating pressure—not by the product color or a generic “heavy duty” label.
The correct construction depends on how the duct must remain open, how it will be suspended and how frequently the route will change.
A collapsible duct body that inflates when the fan is operating and packs flat for transport and storage.
A continuous steel helix supports the airway when the system is under negative pressure or routed through bends.
A redistributed cross-section that preserves useful airflow area while reducing vertical interference.
Real project supply includes more than a material description. The images below show the variety of flexible duct forms and field conditions supported by DERFLEX.
Use this table to prepare an inquiry. Final values should be confirmed on the approved product datasheet and relevant test documents for the exact construction ordered.
| Supply format | Finished duct sections and optional accessories | Fabric body, seams, suspension, reinforcement and agreed interfaces supplied as a coordinated item. |
|---|---|---|
| Airflow duty | Positive pressure, negative pressure or project combination | Pressure direction determines whether a layflat or shape-supported structure is appropriate. |
| Base construction | Woven or knitted polyester with PVC coating on both sides | Fabric structure and coating formulation are selected around strength, weldability, handling and environment. |
| Reference fabric weight | Approximately 400�C900 g/m2 | Final weight depends on duct type, diameter, pressure demand and safety treatment. |
| Reference diameter | Approximately 300�C3000 mm | Non-standard sizes can be reviewed after airflow and installation data are provided. |
| Section length | Common project options from 5�C300 m | Length selection should balance leakage control, handling, repair strategy and shipping volume. |
| Reinforcement | None continuous, spring-steel helix or oval shape control | Selected according to positive pressure, suction duty, bend radius and available clearance. |
| Connections | Zipper, hook-and-loop, steel ring, eyelet, clamp or soft cuff | Fan interfaces and replacement sections should use one documented connection standard. |
| Suspension | Single row, double row, fins, grommets or custom geometry | Spacing and reinforcement are coordinated with diameter, weight and tunnel alignment. |
| Performance options | Flame-retardant, antistatic, high-visibility color and wear protection | Required test method, limit and certificate format must be stated before quotation. |
| Accessories | Reducers, bends, tees, wyes, fan adapters, patches and repair kits | Accessories can be included on the same bill of materials to simplify installation and future maintenance. |
A useful manufacturing specification controls the parts buyers see in the quotation and the details installers discover only after the shipment arrives.
Polyester structure, PVC formulation, weight and optional treatments are selected around pressure, abrasion, flexibility and market requirements.
Weld layout, overlap width and cuff fabrication are standardized to support airtightness and consistent section geometry.
Wire diameter, pitch, wear strip and suspension reinforcement are coordinated rather than added as unrelated components.
Fan outlet measurements, coupling orientation and accessory dimensions are checked against the approved drawing or sample.
Visual checks, dimensions, connection details and agreed performance documents can be organized around the purchase specification.
Section identification, installation order, OEM marks, packing units and spare parts can be defined for easier jobsite control.
Document the duct type, interfaces, suspension and material treatment once. That record helps procurement teams avoid mixing incompatible sections during maintenance or repeat purchasing.
Flexible ducting is useful when the air route must advance, bend, relocate or connect to temporary equipment without the installation burden of rigid metal ductwork.
Fresh-air delivery and localized extraction for headings, drifts, equipment zones and temporary work areas.
Extendable duct lines for metro, railway, highway, utility, hydropower and water-conveyance projects.
Duct packages aligned with advancing machinery, service routes, cross passages and changing installation clearances.
Temporary transfer of dust, fumes, heat or process air during maintenance, production changes and equipment installation.
Portable air supply or exhaust for tanks, chambers, shipyards, basements and controlled-entry maintenance zones.
Air movement for drying, cooling, heating and enclosure ventilation at construction and industrial sites.
A complete first inquiry reduces quotation assumptions and makes it easier to compare proposals on the same technical basis.
These six DERFLEX resources help buyers move from a general manufacturing inquiry to a pressure-specific product or raw-material specification.
The answers below are intentionally project-focused because flexible ventilation duct performance depends on the confirmed construction and operating conditions.
Send the pressure direction, fan data, diameter, total run, connection preference, site layout and required test standard. DERFLEX will review the manufacturing route and prepare a project-based quotation without using unverified universal performance claims.