Customizable circular mobile HEPA room air filter

Customizable air filter for circular HEPA filters and high pressure computer fans with air duct.

It needs a round replacement HEPA filter for air purifiers (exemplary filter product search) and a high pressure computer fan (exemplary fan product search), and provides three printable parts: A bottom cover for the filter, an adapter of the filter to the fan, and an air-guide to be placed on top of the fan for improved room air exchange and finger protection.

Using the customizer or OpenSCAD, the design can be configured for various filter and fan sizes. The given STL files support 120mm, 140mm or 180mm fans for 103mm, 170mm or 185mm diameter filters as specified in the sections below. With a voltage controlled Step-Up USB power-source for at least 12V at 5W, this air filter can be powered with a USB power bank for mobile use. Of course, any other form of power supply for regulated voltage from 6V up to 12V is an alternative, depending on the desired setup.

The design was inspired by a talk of M. Schieder and T. Osterkamp on 29.12.2020 at #rc3, see their air filter project repository at github.

The design should be printable without support having at most 45° overhang (configurable) or very small openings at screw holes. If you run into trouble printing the air-guide, try disabling retraction, and clean the grid afterwards.