A mixture of rejecting overpriced technology and interest in the capability of building this on my own paired with various allergies made me kicking of this project.
I plan to add CFD simulations here as well as 3D-Printable parts to rebuild this Air Purifier, that's why I created an repo.
Goal for this project is to build an air purifier which is considerably quieter than comparable commercial products and does not knock of more than
I decided to go for the air filter below as this one is available quite cheap and has good reviews also from TÜV.
Air filter from Philips 800 Series. HEPA-2 bis
It has an inner diameter around
Just for comparison they are compatible with Philip's air purifier having the following specs:
- rated for an room size up to
$49~m^2$ - airflow-rate of
$190~m^3/h$ - noise emission of
$35~dB$
I put together some fans which have quite promising specs. Note that aboves spec for Philip's air purifier are rated with the filter installed. So while below air flow rate of the fans will easily beat the one specified by Philips, they will drop after the filter being installed. As there is not much spec regarding the filter itself, they would need to be measured afterwards for proper comparability.
| Modelname | Airflow rate |
Noise emission |
Costs p.u. |
|---|---|---|---|
| NB XK-2 | 85.0 | 20 | 9 |
| NB B14-3 | 178.3 | 28.7 | 25 |
| SST AP140 | 109.3 | 30.1 | 18 |
| SST FHP141 | 290.5 | 43 | 19 |
.. was easier than I thought. The filter comes with some foam-ring which initially had the wrong diameter to correctly seal the fan, but was easily removable. Some wooden-screws and due to the stiff filter frame the fans were mounted good enough for a test run.
The fans were installed on both ends in an "Pull-Pull" configuration, as this is the intended airflow direction for this filter.
I used the NB XK-2 which turned out being not hearable at all but producing too less airflow. They are moving an noticeable amount of air, which I would consider being equal to the lowest airflow rate of a commercial product which I tested.
My assumption is that not only the airflow rate, but also the capability of the fan for creating an negative pressure is important for this usecase.
That's why I ordered the NB B14-3 which have a much smaller outer gap between blades and the frame and therefore are capable of producing an higher static pressure.