An inline mixed flow duct fan that mounts directly in a circular duct run. The mixed-flow impeller develops enough pressure for a ducted system while staying quiet at domestic speeds, and every model has a built-in check valve to stop backdraughts when the fan is off. Four models cover duct diameters from φ97 mm to φ196 mm and areas from roughly 6 m² to 45 m².
In duct runs, plant connections and commissioning points, duct accessories is rarely the whole system — it is one link in a chain. Getting it wrong shows up later as noise break-through, flow regulation and on-site modification. The selection criteria that actually drive performance are acoustic attenuation, regulation range and durability, and those are the three things a buyer should confirm before placing an order.
A duct silencer reduces noise by absorbing acoustic energy as the air passes through an internally lined section. Its performance is frequency-dependent: a given unit will attenuate some octave bands far more effectively than others. Selecting a silencer purely on its overall attenuation figure, without reference to the frequency content of the noise it has to control, frequently delivers disappointing results in practice. The correct approach is to match the silencer to the dominant frequency band of the fan and system.
Dampers are the commissioning interface of a ventilation system, and their placement determines whether a system can be balanced at all. A damper buried behind a sealed ceiling is effectively an uncommissionable system. Good practice is to locate regulation devices where they can be reached and adjusted, and to prefer a device with a defined and repeatable setting mechanism over one that can only be guessed at. Every damper also adds pressure loss and, if throttled significantly, velocity noise.
Every Inline Mixed Flow Duct Fan, Low Noise Circular Pipe Ventilation Fan with Check Valve for HVAC Fresh Air Exhaust System we ship is produced on our own production line in Dezhou, Shandong, China. Because we control the tooling and the forming equipment directly, we can guarantee that the product you receive in container three is dimensionally identical to the sample you approved in the first order. That consistency is difficult to achieve when production is outsourced, and it is the single most common complaint we hear from buyers who have tried sourcing this category through intermediaries.
Our mould shop supports custom development for Inline Mixed Flow Duct Fan, Low Noise Circular Pipe Ventilation Fan with Check Valve for HVAC Fresh Air Exhaust System. If your project needs a non-standard size, a specific wall thickness, a particular colour or a branded face plate, we can build the tooling and run a trial batch for approval before committing to a full production run. Typical custom development takes two to four weeks from drawing approval to first article, depending on the complexity of the part.
Confirm the exact size or model you need against the specification table below. Where a project mixes sizes on one run, check that every transition is made with a matching reducer rather than by forcing parts together — the latter is the single most common cause of leakage and pressure loss on site.
The material and layer build-up determine how the product behaves over a 15–25 year service life. Read the construction column carefully: two products that look identical on a photograph can differ entirely in wall thickness, insulation layer and fire performance.
| Item | Specification |
|---|---|
| Available Sizes / Models | DJT10-13A / DJT10-23A / DJT15-45A / DJT20-55A; custom specifications supported |
| Description | Available in 4 models with matching duct diameters of φ97mm, φ147mm and φ196mm; most models feature 2 adjustable speed gears (high & low); all units equipped with built-in check valve; inline circular duct mounting design with fixing brackets; complete mounting accessories included; applicable area ranges from 6㎡ to 45 |
| Material / Construction | Flame-retardant ABS plastic housing; high-efficiency energy-saving motor; dynamically balanced impeller |
Fits into flexible duct or rigid circular duct runs, and works with our electric volume damper and external wall vent cap.
GUANDE manufactures Inline Mixed Flow Duct Fan, Low Noise Circular Pipe Ventilation Fan with Check Valve for HVAC Fresh Air Exhaust System at our factory in Dezhou, Shandong, China, and ships direct to HVAC contractors, distributors and project specifiers worldwide. Wholesale, OEM and ODM programmes are welcome. Because we manufacture this product in our own plant, we control the tooling, wall thickness, material grade and quality inspection at every stage — not just the final packing. That means we can produce non-standard sizes, custom colours and private-label versions against your drawings, and we can adjust a production run when a project specification changes. Tell us your target market and we will confirm packaging, labelling and documentation to suit it.
The products below are routinely specified alongside the item discussed in this guide. GUANDE manufactures the full range in our own plant for consolidated shipping:
Q: Which model do I need for my room?
A: Model selection depends on room volume and duct length. The four models cover approximately 6 to 45 m²; see the specification table and confirm with our team.
Q: Does it have a built-in check valve?
A: Yes, all units are supplied with a built-in check valve.
Q: Can the speed be adjusted?
A: Most models offer two speed gears, high and low.
The southeast corner of the private entrepreneurship park in Huadian Town, Qihui County, Dezhou City, Shandong Province