Centrifugal is an impeller principle
A centrifugal wheel receives air near its centre and moves it outwards through the rotating passages. The casing and surrounding arrangement guide the flow and help develop the required pressure. A common scroll-cased arrangement has different inlet and outlet directions.
That principle does not specify the casing material, motor position, speed control or chemical suitability. Those are model-level details. Our explanation of what a centrifugal fan is covers the main components.
Use the manufacturer’s performance curve to establish whether the proposed model meets the required airflow and pressure at a suitable operating point.
Inline describes the duct arrangement
An inline fan is arranged to connect within a duct run, often with inlet and outlet generally along the duct route. The internal aerodynamic design may be axial, mixed-flow or centrifugal.
When a quotation says only inline, ask for the impeller type, materials and performance data. A compact general-ventilation product is not automatically appropriate for chemical extraction, even if its connections fit the duct.
The arrangement also affects access. Consider how the motor, wheel and other service items will be reached, isolated and removed once the fan is installed above a ceiling or within a restricted space.
Inline vs centrifugal fan: compare the actual models
| Question | Information needed |
|---|---|
| Will it meet the duty? | Airflow and pressure curve at the stated speed and density. |
| Will it tolerate the process? | Casing, wheel, seals and motor arrangement against the chemical exposure. |
| Will it fit? | Connections, supports, service envelope and removal route. |
| How will it operate? | Controls, operating range, electrical input and maintenance instructions. |
Compare the same pressure basis. A maximum free-air flow figure cannot substitute for performance against the resistance of the connected duct system.
A centrifugal inline fan is not a contradiction
The two descriptions can both be true: a fan can have an inline duct arrangement and use a centrifugal wheel inside. Internal flow paths and guide components allow different external connection arrangements.
For a layout decision, draw the required route rather than choosing from a category name. A scroll-cased fan may suit one change in direction; an inline arrangement may suit another space. Include the transitions and access needed by the actual product.
Poor connections can reduce delivered performance. The system-effect guide explains why a fan’s inlet and outlet surroundings deserve attention during selection.
Keep chemical-extraction suitability central
List substances, concentrations, air temperature and possible condensate or deposits. Review the complete exhaust path, including duct, joints and fan components. A suitable impeller principle does not make an unsuitable material compatible.
Our chemical exhaust fan guide explains the exposure brief. For our equipment options, use the Fumeflow D250 and TD250 selection guide.
Once selected, retain the drawing, curve, operating settings and commissioning results. Those records support maintenance and make future replacement comparisons more reliable than matching the word inline on a quotation.
Questions about centrifugal fan vs inline fan
Can an inline fan be centrifugal?
Yes. Inline describes the connection arrangement, while centrifugal describes the impeller principle. Read the model’s construction and performance information.
Is a centrifugal fan always better for chemical extraction?
The required duty and compatible construction decide suitability. Check chemical resistance against the proposed construction and assess performance in the installed system.