This page sets out the technical specification of Inline Mixed Flow Duct Fan, Low Noise Circular Pipe Ventilation Fan with Check Valve for HVAC Fresh Air Exhaust System as supplied by GUANDE, together with the selection rules that determine which variant suits a given project. It is written for specifiers, estimators and contractors who need to confirm a size, a material build-up and a connection method without waiting on a quotation.
| 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 |
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.
Ventilation ducting almost always has to be modified on site, and the quality of that modification determines the final performance of the run. Cut edges must be square and deburred, because a ragged edge will not seal and will generate turbulence. The correct cutting tool for the material is not optional — using a saw intended for another material typically produces an oval or distorted cut that no connector will seal against. Purpose-made cutters pay for themselves on the first project.
Every concealed ventilation system should have a defined set of inspection points, and these should be decided at design stage rather than improvised on site. At minimum, access is needed at the plant connection, at any damper or regulation device, and at intervals along long runs where debris could accumulate. Access panels are inexpensive; cutting an opening into a finished ceiling to reach a component that should have been serviceable is not.
Increasingly, ventilation systems are specified with humidity or CO2 sensors that modulate fan speed according to actual demand rather than running at a fixed rate. This reduces energy consumption and improves comfort, but it places additional requirements on the ductwork. A system designed for a fixed flow may become noisy at the higher speeds a demand-based control will command, and the accessories in the run must be selected with that operating range in mind.
Quality inspection at GUANDE is not a final gate — it runs through the whole process. Incoming raw material is checked against specification before it enters production. In-process checks monitor dimensions and surface finish at defined intervals during the run. Finished Inline Mixed Flow Duct Fan, Low Noise Circular Pipe Ventilation Fan with Check Valve for HVAC Fresh Air Exhaust System are inspected against the approved sample, and a batch record is kept against every shipment so that any issue can be traced back to its production parameters.
Our plant runs scheduled production for Inline Mixed Flow Duct Fan, Low Noise Circular Pipe Ventilation Fan with Check Valve for HVAC Fresh Air Exhaust System with typical lead times of 15 to 25 days for standard items and 25 to 40 days for custom tooling projects. We load mixed containers directly at the factory, which lets us combine several product lines from your ventilation schedule into one shipment and reduce freight cost per unit. Confirmed lead times are stated on the order acknowledgement, not estimated at enquiry.
Use the following rules when converting a project drawing into an order. They reflect how the product performs in duct runs, plant connections and commissioning points, where the practical limits are usually set by acoustic attenuation, regulation range and durability rather than by the headline dimension.
Size the run from the design air flow and the acceptable pressure drop, not from the fan spigot. Undersizing a duct accessories run is the most common specification error and it cannot be corrected later without re-opening the ceiling.
Where the run passes through an unconditioned space, condensation risk — not mechanical strength — normally decides the specification. In those locations the insulated variant is the correct default and a bare equivalent is a false economy.
Keep one connector family for the whole run. Every change of system introduces an adapter, and every adapter is an additional leak path and pressure loss point.
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. Items are supplied in export cartons with the size and quantity marked on the outer label. For OEM programmes we can apply your own artwork and labelling subject to a minimum order quantity.
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