Air Purifier with single filter and a 120mm Fan

Update: I added  2 variants of the top plate that allows to use a 12 V 4 Pin PWM Fan (+Control Board)

Additionally the middle plate was adjusted to work better with some additional activated carbon compartment, that I designed https://www.printables.com/model/1076490-additional-activated-carbon-for-air-purifier.

Movtivation

For some time now I looked into buying an Air Purifier for at home use. While researching I stumbled upon the model I used as a base model for my remix (see other section for differences). The argument, that basically every Air Purifier out there in the market is not much more than a filter, a fan, and a body, was convincing to me. For me the whole smartphone app control, or automatic mode (based on some air quality sensor) is not really an appeal – I use my own air quality sensors already. 

As a matter of fact, there are a lot of aftermarket filters to replace the originals, and those will do all the work. Additionally a 120 mm fan should also easy to be sourced and so I started to look into parts. 

In the end I tried to get the same filters as the remixed model, but I had to source them differently. Also I wanted a different fan solution, which was more ready out of the box. 

With the update I added a variant that can be used with a 12 V 4 Pin PWM Fan, but needs a PWM Control Board and a 12 V connection. 

Additional Parts:

So I sourced the following parts (no affiliation links):

Filter: (2 pieces)

https://www.amazon.de/dp/B0CDBJVF9G

Bonus: If you get these filters, also have a look at my additional active carbon compartment: https://www.printables.com/model/1076490-additional-activated-carbon-for-air-purifier

Basic Fans including switch and speed control (2 pieces):

https://www.amazon.de/dp/B081SYD24Z

Or (updated): 12V 120mm 4 Pin PWM Fans  + PWM Control Module 

I got myself a Noctua:

https://www.amazon.de/dp/B07CG2PGY6

and this PWM Controller:

https://www.amazon.de/dp/B0D8PRTCV7

and this 12V Power Module (it comes with an additional female connector):

https://www.amazon.de/gp/product/B0CGD23B6G

If you have a different 12V Power, then you may need some female connectors like these:

https://www.amazon.de/gp/product/B0836N82PR

For both type of female connectors there are specific top plate models.

The basic design should fit for most 120 mm fans with height 25mm and standard connections. 

The updated top plate (TopNoctua) is adjusted to have some inside space for cables and PWM Module + external connector. For the external connector there are two variants, one with a rectangular and one with a round female connector. 

Additionally I used some M3x40mm screws (4 per box) and M3 nuts. To hold the thing down I used a kind of rubber band (sourced locally in a shop on a 5m roll) that was cut into 32cm pieces (2 times).

Print / assembly instructions:

For a single unit (you can make two with the filters and fans from above) just print a base part, a middle part and a top part. All three parts can be placed flat on the print bed and can be printed without supports. The “Fresh Air” on the top plate is not part of the model, but was created using the Text Tool in Bambu Studio. 

Put the filter onto the base part with the closed filter side to the bottom. 

Put the fan in the middle part and the top part on top of it. Take care that the “ring” of the middle part faces down, this goes on top of the filter. 

For the usb fan variant:

Put the top part on such that the cable of the fan can go through the opening on the side, and the flat side being on top. 

For the pwm fan variant:

Solder two power wires to bottom side of the PWM control board, facing away from the speed knob. Connect those wires to the female connector. Place the top plate with top side facing bottom on a table, put the PWM control knob through the side wall at the hole, and do the same with female power connector. Put the PWM Fan inside and (if it has a longer connection cable) lay the cable around, connect it to the 4-pin connector on the PWM Control board.

Fix those three parts (middel part, fan, top part) with the M3x40mm screws and nuts and if you prefer, do not forget to also mount the fan grill (I did forget that…). Also put the fan in such that it blows out at the top part. 

Put that on top of the filter. To hold it in place, make two loops out of those two 32cm pieces of rubber band, and align those cavities in the bottom plate and on the middle plate, which you can use to put your rubber band in. 

Connect to a (usb) outlet and switch it on. Enjoy filtered air!